Moved, renamed, and deleted files

The original directory structure was scattered and unorganized.
Changes are basically to make it look like kernel structure.

28 files changed, 8792 insertions, 0 deletions

diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
new file mode 100644
index 00000000..fdce49c7
--- /dev/null
+++ b/arch/x86/xen/Kconfig
@@ -0,0 +1,52 @@
+#
+# This Kconfig describes xen options
+#
+
+config XEN
+	bool "Xen guest support"
+	select PARAVIRT
+	select PARAVIRT_CLOCK
+	depends on X86_64 || (X86_32 && X86_PAE && !X86_VISWS)
+	depends on X86_CMPXCHG && X86_TSC
+	help
+	  This is the Linux Xen port.  Enabling this will allow the
+	  kernel to boot in a paravirtualized environment under the
+	  Xen hypervisor.
+
+config XEN_DOM0
+	def_bool y
+	depends on XEN && PCI_XEN && SWIOTLB_XEN
+	depends on X86_LOCAL_APIC && X86_IO_APIC && ACPI && PCI
+
+# Dummy symbol since people have come to rely on the PRIVILEGED_GUEST
+# name in tools.
+config XEN_PRIVILEGED_GUEST
+	def_bool XEN_DOM0
+
+config XEN_PVHVM
+	def_bool y
+	depends on XEN && PCI && X86_LOCAL_APIC
+
+config XEN_MAX_DOMAIN_MEMORY
+       int
+       default 500 if X86_64
+       default 64 if X86_32
+       depends on XEN
+       help
+         This only affects the sizing of some bss arrays, the unused
+         portions of which are freed.
+
+config XEN_SAVE_RESTORE
+       bool
+       depends on XEN
+       select HIBERNATE_CALLBACKS
+       default y
+
+config XEN_DEBUG_FS
+	bool "Enable Xen debug and tuning parameters in debugfs"
+	depends on XEN && DEBUG_FS
+	default n
+	help
+	  Enable statistics output and various tuning options in debugfs.
+	  Enabling this option may incur a significant performance overhead.
+
diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
new file mode 100644
index 00000000..add2c2d7
--- /dev/null
+++ b/arch/x86/xen/Makefile
@@ -0,0 +1,24 @@
+ifdef CONFIG_FUNCTION_TRACER
+# Do not profile debug and lowlevel utilities
+CFLAGS_REMOVE_spinlock.o = -pg
+CFLAGS_REMOVE_time.o = -pg
+CFLAGS_REMOVE_irq.o = -pg
+endif
+
+# Make sure early boot has no stackprotector
+nostackp := $(call cc-option, -fno-stack-protector)
+CFLAGS_enlighten.o		:= $(nostackp)
+CFLAGS_mmu.o			:= $(nostackp)
+
+obj-y		:= enlighten.o setup.o multicalls.o mmu.o irq.o \
+			time.o xen-asm.o xen-asm_$(BITS).o \
+			grant-table.o suspend.o platform-pci-unplug.o \
+			p2m.o
+
+obj-$(CONFIG_EVENT_TRACING) += trace.o
+
+obj-$(CONFIG_SMP)		+= smp.o
+obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= spinlock.o
+obj-$(CONFIG_XEN_DEBUG_FS)	+= debugfs.o
+obj-$(CONFIG_XEN_DOM0)		+= vga.o
+obj-$(CONFIG_SWIOTLB_XEN)	+= pci-swiotlb-xen.o
diff --git a/arch/x86/xen/debugfs.c b/arch/x86/xen/debugfs.c
new file mode 100644
index 00000000..ef1db190
--- /dev/null
+++ b/arch/x86/xen/debugfs.c
@@ -0,0 +1,125 @@
+#include <linux/init.h>
+#include <linux/debugfs.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+
+#include "debugfs.h"
+
+static struct dentry *d_xen_debug;
+
+struct dentry * __init xen_init_debugfs(void)
+{
+	if (!d_xen_debug) {
+		d_xen_debug = debugfs_create_dir("xen", NULL);
+
+		if (!d_xen_debug)
+			pr_warning("Could not create 'xen' debugfs directory\n");
+	}
+
+	return d_xen_debug;
+}
+
+struct array_data
+{
+	void *array;
+	unsigned elements;
+};
+
+static int u32_array_open(struct inode *inode, struct file *file)
+{
+	file->private_data = NULL;
+	return nonseekable_open(inode, file);
+}
+
+static size_t format_array(char *buf, size_t bufsize, const char *fmt,
+			   u32 *array, unsigned array_size)
+{
+	size_t ret = 0;
+	unsigned i;
+
+	for(i = 0; i < array_size; i++) {
+		size_t len;
+
+		len = snprintf(buf, bufsize, fmt, array[i]);
+		len++;	/* ' ' or '\n' */
+		ret += len;
+
+		if (buf) {
+			buf += len;
+			bufsize -= len;
+			buf[-1] = (i == array_size-1) ? '\n' : ' ';
+		}
+	}
+
+	ret++;		/* \0 */
+	if (buf)
+		*buf = '\0';
+
+	return ret;
+}
+
+static char *format_array_alloc(const char *fmt, u32 *array, unsigned array_size)
+{
+	size_t len = format_array(NULL, 0, fmt, array, array_size);
+	char *ret;
+
+	ret = kmalloc(len, GFP_KERNEL);
+	if (ret == NULL)
+		return NULL;
+
+	format_array(ret, len, fmt, array, array_size);
+	return ret;
+}
+
+static ssize_t u32_array_read(struct file *file, char __user *buf, size_t len,
+			      loff_t *ppos)
+{
+	struct inode *inode = file->f_path.dentry->d_inode;
+	struct array_data *data = inode->i_private;
+	size_t size;
+
+	if (*ppos == 0) {
+		if (file->private_data) {
+			kfree(file->private_data);
+			file->private_data = NULL;
+		}
+
+		file->private_data = format_array_alloc("%u", data->array, data->elements);
+	}
+
+	size = 0;
+	if (file->private_data)
+		size = strlen(file->private_data);
+
+	return simple_read_from_buffer(buf, len, ppos, file->private_data, size);
+}
+
+static int xen_array_release(struct inode *inode, struct file *file)
+{
+	kfree(file->private_data);
+
+	return 0;
+}
+
+static const struct file_operations u32_array_fops = {
+	.owner	= THIS_MODULE,
+	.open	= u32_array_open,
+	.release= xen_array_release,
+	.read	= u32_array_read,
+	.llseek = no_llseek,
+};
+
+struct dentry *xen_debugfs_create_u32_array(const char *name, umode_t mode,
+					    struct dentry *parent,
+					    u32 *array, unsigned elements)
+{
+	struct array_data *data = kmalloc(sizeof(*data), GFP_KERNEL);
+
+	if (data == NULL)
+		return NULL;
+
+	data->array = array;
+	data->elements = elements;
+
+	return debugfs_create_file(name, mode, parent, data, &u32_array_fops);
+}
diff --git a/arch/x86/xen/debugfs.h b/arch/x86/xen/debugfs.h
new file mode 100644
index 00000000..78d25499
--- /dev/null
+++ b/arch/x86/xen/debugfs.h
@@ -0,0 +1,10 @@
+#ifndef _XEN_DEBUGFS_H
+#define _XEN_DEBUGFS_H
+
+struct dentry * __init xen_init_debugfs(void);
+
+struct dentry *xen_debugfs_create_u32_array(const char *name, umode_t mode,
+					    struct dentry *parent,
+					    u32 *array, unsigned elements);
+
+#endif /* _XEN_DEBUGFS_H */
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
new file mode 100644
index 00000000..40edfc37
--- /dev/null
+++ b/arch/x86/xen/enlighten.c
@@ -0,0 +1,1557 @@
+/*
+ * Core of Xen paravirt_ops implementation.
+ *
+ * This file contains the xen_paravirt_ops structure itself, and the
+ * implementations for:
+ * - privileged instructions
+ * - interrupt flags
+ * - segment operations
+ * - booting and setup
+ *
+ * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
+ */
+
+#include <linux/cpu.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/preempt.h>
+#include <linux/hardirq.h>
+#include <linux/percpu.h>
+#include <linux/delay.h>
+#include <linux/start_kernel.h>
+#include <linux/sched.h>
+#include <linux/kprobes.h>
+#include <linux/bootmem.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/page-flags.h>
+#include <linux/highmem.h>
+#include <linux/console.h>
+#include <linux/pci.h>
+#include <linux/gfp.h>
+#include <linux/memblock.h>
+
+#include <xen/xen.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/version.h>
+#include <xen/interface/physdev.h>
+#include <xen/interface/vcpu.h>
+#include <xen/interface/memory.h>
+#include <xen/features.h>
+#include <xen/page.h>
+#include <xen/hvm.h>
+#include <xen/hvc-console.h>
+
+#include <asm/paravirt.h>
+#include <asm/apic.h>
+#include <asm/page.h>
+#include <asm/xen/pci.h>
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+#include <asm/fixmap.h>
+#include <asm/processor.h>
+#include <asm/proto.h>
+#include <asm/msr-index.h>
+#include <asm/traps.h>
+#include <asm/setup.h>
+#include <asm/desc.h>
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+#include <asm/reboot.h>
+#include <asm/stackprotector.h>
+#include <asm/hypervisor.h>
+#include <asm/mwait.h>
+#include <asm/pci_x86.h>
+
+#ifdef CONFIG_ACPI
+#include <linux/acpi.h>
+#include <asm/acpi.h>
+#include <acpi/pdc_intel.h>
+#include <acpi/processor.h>
+#include <xen/interface/platform.h>
+#endif
+
+#include "xen-ops.h"
+#include "mmu.h"
+#include "multicalls.h"
+
+EXPORT_SYMBOL_GPL(hypercall_page);
+
+DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
+DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info);
+
+enum xen_domain_type xen_domain_type = XEN_NATIVE;
+EXPORT_SYMBOL_GPL(xen_domain_type);
+
+unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START;
+EXPORT_SYMBOL(machine_to_phys_mapping);
+unsigned long  machine_to_phys_nr;
+EXPORT_SYMBOL(machine_to_phys_nr);
+
+struct start_info *xen_start_info;
+EXPORT_SYMBOL_GPL(xen_start_info);
+
+struct shared_info xen_dummy_shared_info;
+
+void *xen_initial_gdt;
+
+RESERVE_BRK(shared_info_page_brk, PAGE_SIZE);
+__read_mostly int xen_have_vector_callback;
+EXPORT_SYMBOL_GPL(xen_have_vector_callback);
+
+/*
+ * Point at some empty memory to start with. We map the real shared_info
+ * page as soon as fixmap is up and running.
+ */
+struct shared_info *HYPERVISOR_shared_info = (void *)&xen_dummy_shared_info;
+
+/*
+ * Flag to determine whether vcpu info placement is available on all
+ * VCPUs.  We assume it is to start with, and then set it to zero on
+ * the first failure.  This is because it can succeed on some VCPUs
+ * and not others, since it can involve hypervisor memory allocation,
+ * or because the guest failed to guarantee all the appropriate
+ * constraints on all VCPUs (ie buffer can't cross a page boundary).
+ *
+ * Note that any particular CPU may be using a placed vcpu structure,
+ * but we can only optimise if the all are.
+ *
+ * 0: not available, 1: available
+ */
+static int have_vcpu_info_placement = 1;
+
+static void clamp_max_cpus(void)
+{
+#ifdef CONFIG_SMP
+	if (setup_max_cpus > MAX_VIRT_CPUS)
+		setup_max_cpus = MAX_VIRT_CPUS;
+#endif
+}
+
+static void xen_vcpu_setup(int cpu)
+{
+	struct vcpu_register_vcpu_info info;
+	int err;
+	struct vcpu_info *vcpup;
+
+	BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
+
+	if (cpu < MAX_VIRT_CPUS)
+		per_cpu(xen_vcpu,cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
+
+	if (!have_vcpu_info_placement) {
+		if (cpu >= MAX_VIRT_CPUS)
+			clamp_max_cpus();
+		return;
+	}
+
+	vcpup = &per_cpu(xen_vcpu_info, cpu);
+	info.mfn = arbitrary_virt_to_mfn(vcpup);
+	info.offset = offset_in_page(vcpup);
+
+	/* Check to see if the hypervisor will put the vcpu_info
+	   structure where we want it, which allows direct access via
+	   a percpu-variable. */
+	err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info);
+
+	if (err) {
+		printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err);
+		have_vcpu_info_placement = 0;
+		clamp_max_cpus();
+	} else {
+		/* This cpu is using the registered vcpu info, even if
+		   later ones fail to. */
+		per_cpu(xen_vcpu, cpu) = vcpup;
+	}
+}
+
+/*
+ * On restore, set the vcpu placement up again.
+ * If it fails, then we're in a bad state, since
+ * we can't back out from using it...
+ */
+void xen_vcpu_restore(void)
+{
+	int cpu;
+
+	for_each_online_cpu(cpu) {
+		bool other_cpu = (cpu != smp_processor_id());
+
+		if (other_cpu &&
+		    HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL))
+			BUG();
+
+		xen_setup_runstate_info(cpu);
+
+		if (have_vcpu_info_placement)
+			xen_vcpu_setup(cpu);
+
+		if (other_cpu &&
+		    HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL))
+			BUG();
+	}
+}
+
+static void __init xen_banner(void)
+{
+	unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
+	struct xen_extraversion extra;
+	HYPERVISOR_xen_version(XENVER_extraversion, &extra);
+
+	printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
+	       pv_info.name);
+	printk(KERN_INFO "Xen version: %d.%d%s%s\n",
+	       version >> 16, version & 0xffff, extra.extraversion,
+	       xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
+}
+
+#define CPUID_THERM_POWER_LEAF 6
+#define APERFMPERF_PRESENT 0
+
+static __read_mostly unsigned int cpuid_leaf1_edx_mask = ~0;
+static __read_mostly unsigned int cpuid_leaf1_ecx_mask = ~0;
+
+static __read_mostly unsigned int cpuid_leaf1_ecx_set_mask;
+static __read_mostly unsigned int cpuid_leaf5_ecx_val;
+static __read_mostly unsigned int cpuid_leaf5_edx_val;
+
+static void xen_cpuid(unsigned int *ax, unsigned int *bx,
+		      unsigned int *cx, unsigned int *dx)
+{
+	unsigned maskebx = ~0;
+	unsigned maskecx = ~0;
+	unsigned maskedx = ~0;
+	unsigned setecx = 0;
+	/*
+	 * Mask out inconvenient features, to try and disable as many
+	 * unsupported kernel subsystems as possible.
+	 */
+	switch (*ax) {
+	case 1:
+		maskecx = cpuid_leaf1_ecx_mask;
+		setecx = cpuid_leaf1_ecx_set_mask;
+		maskedx = cpuid_leaf1_edx_mask;
+		break;
+
+	case CPUID_MWAIT_LEAF:
+		/* Synthesize the values.. */
+		*ax = 0;
+		*bx = 0;
+		*cx = cpuid_leaf5_ecx_val;
+		*dx = cpuid_leaf5_edx_val;
+		return;
+
+	case CPUID_THERM_POWER_LEAF:
+		/* Disabling APERFMPERF for kernel usage */
+		maskecx = ~(1 << APERFMPERF_PRESENT);
+		break;
+
+	case 0xb:
+		/* Suppress extended topology stuff */
+		maskebx = 0;
+		break;
+	}
+
+	asm(XEN_EMULATE_PREFIX "cpuid"
+		: "=a" (*ax),
+		  "=b" (*bx),
+		  "=c" (*cx),
+		  "=d" (*dx)
+		: "0" (*ax), "2" (*cx));
+
+	*bx &= maskebx;
+	*cx &= maskecx;
+	*cx |= setecx;
+	*dx &= maskedx;
+
+}
+
+static bool __init xen_check_mwait(void)
+{
+#if defined(CONFIG_ACPI) && !defined(CONFIG_ACPI_PROCESSOR_AGGREGATOR) && \
+	!defined(CONFIG_ACPI_PROCESSOR_AGGREGATOR_MODULE)
+	struct xen_platform_op op = {
+		.cmd			= XENPF_set_processor_pminfo,
+		.u.set_pminfo.id	= -1,
+		.u.set_pminfo.type	= XEN_PM_PDC,
+	};
+	uint32_t buf[3];
+	unsigned int ax, bx, cx, dx;
+	unsigned int mwait_mask;
+
+	/* We need to determine whether it is OK to expose the MWAIT
+	 * capability to the kernel to harvest deeper than C3 states from ACPI
+	 * _CST using the processor_harvest_xen.c module. For this to work, we
+	 * need to gather the MWAIT_LEAF values (which the cstate.c code
+	 * checks against). The hypervisor won't expose the MWAIT flag because
+	 * it would break backwards compatibility; so we will find out directly
+	 * from the hardware and hypercall.
+	 */
+	if (!xen_initial_domain())
+		return false;
+
+	ax = 1;
+	cx = 0;
+
+	native_cpuid(&ax, &bx, &cx, &dx);
+
+	mwait_mask = (1 << (X86_FEATURE_EST % 32)) |
+		     (1 << (X86_FEATURE_MWAIT % 32));
+
+	if ((cx & mwait_mask) != mwait_mask)
+		return false;
+
+	/* We need to emulate the MWAIT_LEAF and for that we need both
+	 * ecx and edx. The hypercall provides only partial information.
+	 */
+
+	ax = CPUID_MWAIT_LEAF;
+	bx = 0;
+	cx = 0;
+	dx = 0;
+
+	native_cpuid(&ax, &bx, &cx, &dx);
+
+	/* Ask the Hypervisor whether to clear ACPI_PDC_C_C2C3_FFH. If so,
+	 * don't expose MWAIT_LEAF and let ACPI pick the IOPORT version of C3.
+	 */
+	buf[0] = ACPI_PDC_REVISION_ID;
+	buf[1] = 1;
+	buf[2] = (ACPI_PDC_C_CAPABILITY_SMP | ACPI_PDC_EST_CAPABILITY_SWSMP);
+
+	set_xen_guest_handle(op.u.set_pminfo.pdc, buf);
+
+	if ((HYPERVISOR_dom0_op(&op) == 0) &&
+	    (buf[2] & (ACPI_PDC_C_C1_FFH | ACPI_PDC_C_C2C3_FFH))) {
+		cpuid_leaf5_ecx_val = cx;
+		cpuid_leaf5_edx_val = dx;
+	}
+	return true;
+#else
+	return false;
+#endif
+}
+static void __init xen_init_cpuid_mask(void)
+{
+	unsigned int ax, bx, cx, dx;
+	unsigned int xsave_mask;
+
+	cpuid_leaf1_edx_mask =
+		~((1 << X86_FEATURE_MCE)  |  /* disable MCE */
+		  (1 << X86_FEATURE_MCA)  |  /* disable MCA */
+		  (1 << X86_FEATURE_MTRR) |  /* disable MTRR */
+		  (1 << X86_FEATURE_ACC));   /* thermal monitoring */
+
+	if (!xen_initial_domain())
+		cpuid_leaf1_edx_mask &=
+			~((1 << X86_FEATURE_APIC) |  /* disable local APIC */
+			  (1 << X86_FEATURE_ACPI));  /* disable ACPI */
+	ax = 1;
+	cx = 0;
+	xen_cpuid(&ax, &bx, &cx, &dx);
+
+	xsave_mask =
+		(1 << (X86_FEATURE_XSAVE % 32)) |
+		(1 << (X86_FEATURE_OSXSAVE % 32));
+
+	/* Xen will set CR4.OSXSAVE if supported and not disabled by force */
+	if ((cx & xsave_mask) != xsave_mask)
+		cpuid_leaf1_ecx_mask &= ~xsave_mask; /* disable XSAVE & OSXSAVE */
+	if (xen_check_mwait())
+		cpuid_leaf1_ecx_set_mask = (1 << (X86_FEATURE_MWAIT % 32));
+}
+
+static void xen_set_debugreg(int reg, unsigned long val)
+{
+	HYPERVISOR_set_debugreg(reg, val);
+}
+
+static unsigned long xen_get_debugreg(int reg)
+{
+	return HYPERVISOR_get_debugreg(reg);
+}
+
+static void xen_end_context_switch(struct task_struct *next)
+{
+	xen_mc_flush();
+	paravirt_end_context_switch(next);
+}
+
+static unsigned long xen_store_tr(void)
+{
+	return 0;
+}
+
+/*
+ * Set the page permissions for a particular virtual address.  If the
+ * address is a vmalloc mapping (or other non-linear mapping), then
+ * find the linear mapping of the page and also set its protections to
+ * match.
+ */
+static void set_aliased_prot(void *v, pgprot_t prot)
+{
+	int level;
+	pte_t *ptep;
+	pte_t pte;
+	unsigned long pfn;
+	struct page *page;
+
+	ptep = lookup_address((unsigned long)v, &level);
+	BUG_ON(ptep == NULL);
+
+	pfn = pte_pfn(*ptep);
+	page = pfn_to_page(pfn);
+
+	pte = pfn_pte(pfn, prot);
+
+	if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0))
+		BUG();
+
+	if (!PageHighMem(page)) {
+		void *av = __va(PFN_PHYS(pfn));
+
+		if (av != v)
+			if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0))
+				BUG();
+	} else
+		kmap_flush_unused();
+}
+
+static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries)
+{
+	const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
+	int i;
+
+	for(i = 0; i < entries; i += entries_per_page)
+		set_aliased_prot(ldt + i, PAGE_KERNEL_RO);
+}
+
+static void xen_free_ldt(struct desc_struct *ldt, unsigned entries)
+{
+	const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
+	int i;
+
+	for(i = 0; i < entries; i += entries_per_page)
+		set_aliased_prot(ldt + i, PAGE_KERNEL);
+}
+
+static void xen_set_ldt(const void *addr, unsigned entries)
+{
+	struct mmuext_op *op;
+	struct multicall_space mcs = xen_mc_entry(sizeof(*op));
+
+	trace_xen_cpu_set_ldt(addr, entries);
+
+	op = mcs.args;
+	op->cmd = MMUEXT_SET_LDT;
+	op->arg1.linear_addr = (unsigned long)addr;
+	op->arg2.nr_ents = entries;
+
+	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
+
+	xen_mc_issue(PARAVIRT_LAZY_CPU);
+}
+
+static void xen_load_gdt(const struct desc_ptr *dtr)
+{
+	unsigned long va = dtr->address;
+	unsigned int size = dtr->size + 1;
+	unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
+	unsigned long frames[pages];
+	int f;
+
+	/*
+	 * A GDT can be up to 64k in size, which corresponds to 8192
+	 * 8-byte entries, or 16 4k pages..
+	 */
+
+	BUG_ON(size > 65536);
+	BUG_ON(va & ~PAGE_MASK);
+
+	for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
+		int level;
+		pte_t *ptep;
+		unsigned long pfn, mfn;
+		void *virt;
+
+		/*
+		 * The GDT is per-cpu and is in the percpu data area.
+		 * That can be virtually mapped, so we need to do a
+		 * page-walk to get the underlying MFN for the
+		 * hypercall.  The page can also be in the kernel's
+		 * linear range, so we need to RO that mapping too.
+		 */
+		ptep = lookup_address(va, &level);
+		BUG_ON(ptep == NULL);
+
+		pfn = pte_pfn(*ptep);
+		mfn = pfn_to_mfn(pfn);
+		virt = __va(PFN_PHYS(pfn));
+
+		frames[f] = mfn;
+
+		make_lowmem_page_readonly((void *)va);
+		make_lowmem_page_readonly(virt);
+	}
+
+	if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct)))
+		BUG();
+}
+
+/*
+ * load_gdt for early boot, when the gdt is only mapped once
+ */
+static void __init xen_load_gdt_boot(const struct desc_ptr *dtr)
+{
+	unsigned long va = dtr->address;
+	unsigned int size = dtr->size + 1;
+	unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
+	unsigned long frames[pages];
+	int f;
+
+	/*
+	 * A GDT can be up to 64k in size, which corresponds to 8192
+	 * 8-byte entries, or 16 4k pages..
+	 */
+
+	BUG_ON(size > 65536);
+	BUG_ON(va & ~PAGE_MASK);
+
+	for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
+		pte_t pte;
+		unsigned long pfn, mfn;
+
+		pfn = virt_to_pfn(va);
+		mfn = pfn_to_mfn(pfn);
+
+		pte = pfn_pte(pfn, PAGE_KERNEL_RO);
+
+		if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0))
+			BUG();
+
+		frames[f] = mfn;
+	}
+
+	if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct)))
+		BUG();
+}
+
+static void load_TLS_descriptor(struct thread_struct *t,
+				unsigned int cpu, unsigned int i)
+{
+	struct desc_struct *gdt = get_cpu_gdt_table(cpu);
+	xmaddr_t maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]);
+	struct multicall_space mc = __xen_mc_entry(0);
+
+	MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]);
+}
+
+static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
+{
+	/*
+	 * XXX sleazy hack: If we're being called in a lazy-cpu zone
+	 * and lazy gs handling is enabled, it means we're in a
+	 * context switch, and %gs has just been saved.  This means we
+	 * can zero it out to prevent faults on exit from the
+	 * hypervisor if the next process has no %gs.  Either way, it
+	 * has been saved, and the new value will get loaded properly.
+	 * This will go away as soon as Xen has been modified to not
+	 * save/restore %gs for normal hypercalls.
+	 *
+	 * On x86_64, this hack is not used for %gs, because gs points
+	 * to KERNEL_GS_BASE (and uses it for PDA references), so we
+	 * must not zero %gs on x86_64
+	 *
+	 * For x86_64, we need to zero %fs, otherwise we may get an
+	 * exception between the new %fs descriptor being loaded and
+	 * %fs being effectively cleared at __switch_to().
+	 */
+	if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {
+#ifdef CONFIG_X86_32
+		lazy_load_gs(0);
+#else
+		loadsegment(fs, 0);
+#endif
+	}
+
+	xen_mc_batch();
+
+	load_TLS_descriptor(t, cpu, 0);
+	load_TLS_descriptor(t, cpu, 1);
+	load_TLS_descriptor(t, cpu, 2);
+
+	xen_mc_issue(PARAVIRT_LAZY_CPU);
+}
+
+#ifdef CONFIG_X86_64
+static void xen_load_gs_index(unsigned int idx)
+{
+	if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx))
+		BUG();
+}
+#endif
+
+static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
+				const void *ptr)
+{
+	xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]);
+	u64 entry = *(u64 *)ptr;
+
+	trace_xen_cpu_write_ldt_entry(dt, entrynum, entry);
+
+	preempt_disable();
+
+	xen_mc_flush();
+	if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry))
+		BUG();
+
+	preempt_enable();
+}
+
+static int cvt_gate_to_trap(int vector, const gate_desc *val,
+			    struct trap_info *info)
+{
+	unsigned long addr;
+
+	if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT)
+		return 0;
+
+	info->vector = vector;
+
+	addr = gate_offset(*val);
+#ifdef CONFIG_X86_64
+	/*
+	 * Look for known traps using IST, and substitute them
+	 * appropriately.  The debugger ones are the only ones we care
+	 * about.  Xen will handle faults like double_fault and
+	 * machine_check, so we should never see them.  Warn if
+	 * there's an unexpected IST-using fault handler.
+	 */
+	if (addr == (unsigned long)debug)
+		addr = (unsigned long)xen_debug;
+	else if (addr == (unsigned long)int3)
+		addr = (unsigned long)xen_int3;
+	else if (addr == (unsigned long)stack_segment)
+		addr = (unsigned long)xen_stack_segment;
+	else if (addr == (unsigned long)double_fault ||
+		 addr == (unsigned long)nmi) {
+		/* Don't need to handle these */
+		return 0;
+#ifdef CONFIG_X86_MCE
+	} else if (addr == (unsigned long)machine_check) {
+		return 0;
+#endif
+	} else {
+		/* Some other trap using IST? */
+		if (WARN_ON(val->ist != 0))
+			return 0;
+	}
+#endif	/* CONFIG_X86_64 */
+	info->address = addr;
+
+	info->cs = gate_segment(*val);
+	info->flags = val->dpl;
+	/* interrupt gates clear IF */
+	if (val->type == GATE_INTERRUPT)
+		info->flags |= 1 << 2;
+
+	return 1;
+}
+
+/* Locations of each CPU's IDT */
+static DEFINE_PER_CPU(struct desc_ptr, idt_desc);
+
+/* Set an IDT entry.  If the entry is part of the current IDT, then
+   also update Xen. */
+static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g)
+{
+	unsigned long p = (unsigned long)&dt[entrynum];
+	unsigned long start, end;
+
+	trace_xen_cpu_write_idt_entry(dt, entrynum, g);
+
+	preempt_disable();
+
+	start = __this_cpu_read(idt_desc.address);
+	end = start + __this_cpu_read(idt_desc.size) + 1;
+
+	xen_mc_flush();
+
+	native_write_idt_entry(dt, entrynum, g);
+
+	if (p >= start && (p + 8) <= end) {
+		struct trap_info info[2];
+
+		info[1].address = 0;
+
+		if (cvt_gate_to_trap(entrynum, g, &info[0]))
+			if (HYPERVISOR_set_trap_table(info))
+				BUG();
+	}
+
+	preempt_enable();
+}
+
+static void xen_convert_trap_info(const struct desc_ptr *desc,
+				  struct trap_info *traps)
+{
+	unsigned in, out, count;
+
+	count = (desc->size+1) / sizeof(gate_desc);
+	BUG_ON(count > 256);
+
+	for (in = out = 0; in < count; in++) {
+		gate_desc *entry = (gate_desc*)(desc->address) + in;
+
+		if (cvt_gate_to_trap(in, entry, &traps[out]))
+			out++;
+	}
+	traps[out].address = 0;
+}
+
+void xen_copy_trap_info(struct trap_info *traps)
+{
+	const struct desc_ptr *desc = &__get_cpu_var(idt_desc);
+
+	xen_convert_trap_info(desc, traps);
+}
+
+/* Load a new IDT into Xen.  In principle this can be per-CPU, so we
+   hold a spinlock to protect the static traps[] array (static because
+   it avoids allocation, and saves stack space). */
+static void xen_load_idt(const struct desc_ptr *desc)
+{
+	static DEFINE_SPINLOCK(lock);
+	static struct trap_info traps[257];
+
+	trace_xen_cpu_load_idt(desc);
+
+	spin_lock(&lock);
+
+	__get_cpu_var(idt_desc) = *desc;
+
+	xen_convert_trap_info(desc, traps);
+
+	xen_mc_flush();
+	if (HYPERVISOR_set_trap_table(traps))
+		BUG();
+
+	spin_unlock(&lock);
+}
+
+/* Write a GDT descriptor entry.  Ignore LDT descriptors, since
+   they're handled differently. */
+static void xen_write_gdt_entry(struct desc_struct *dt, int entry,
+				const void *desc, int type)
+{
+	trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
+
+	preempt_disable();
+
+	switch (type) {
+	case DESC_LDT:
+	case DESC_TSS:
+		/* ignore */
+		break;
+
+	default: {
+		xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]);
+
+		xen_mc_flush();
+		if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
+			BUG();
+	}
+
+	}
+
+	preempt_enable();
+}
+
+/*
+ * Version of write_gdt_entry for use at early boot-time needed to
+ * update an entry as simply as possible.
+ */
+static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry,
+					    const void *desc, int type)
+{
+	trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
+
+	switch (type) {
+	case DESC_LDT:
+	case DESC_TSS:
+		/* ignore */
+		break;
+
+	default: {
+		xmaddr_t maddr = virt_to_machine(&dt[entry]);
+
+		if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
+			dt[entry] = *(struct desc_struct *)desc;
+	}
+
+	}
+}
+
+static void xen_load_sp0(struct tss_struct *tss,
+			 struct thread_struct *thread)
+{
+	struct multicall_space mcs;
+
+	mcs = xen_mc_entry(0);
+	MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0);
+	xen_mc_issue(PARAVIRT_LAZY_CPU);
+}
+
+static void xen_set_iopl_mask(unsigned mask)
+{
+	struct physdev_set_iopl set_iopl;
+
+	/* Force the change at ring 0. */
+	set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3;
+	HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
+}
+
+static void xen_io_delay(void)
+{
+}
+
+#ifdef CONFIG_X86_LOCAL_APIC
+static unsigned long xen_set_apic_id(unsigned int x)
+{
+	WARN_ON(1);
+	return x;
+}
+static unsigned int xen_get_apic_id(unsigned long x)
+{
+	return ((x)>>24) & 0xFFu;
+}
+static u32 xen_apic_read(u32 reg)
+{
+	struct xen_platform_op op = {
+		.cmd = XENPF_get_cpuinfo,
+		.interface_version = XENPF_INTERFACE_VERSION,
+		.u.pcpu_info.xen_cpuid = 0,
+	};
+	int ret = 0;
+
+	/* Shouldn't need this as APIC is turned off for PV, and we only
+	 * get called on the bootup processor. But just in case. */
+	if (!xen_initial_domain() || smp_processor_id())
+		return 0;
+
+	if (reg == APIC_LVR)
+		return 0x10;
+
+	if (reg != APIC_ID)
+		return 0;
+
+	ret = HYPERVISOR_dom0_op(&op);
+	if (ret)
+		return 0;
+
+	return op.u.pcpu_info.apic_id << 24;
+}
+
+static void xen_apic_write(u32 reg, u32 val)
+{
+	/* Warn to see if there's any stray references */
+	WARN_ON(1);
+}
+
+static u64 xen_apic_icr_read(void)
+{
+	return 0;
+}
+
+static void xen_apic_icr_write(u32 low, u32 id)
+{
+	/* Warn to see if there's any stray references */
+	WARN_ON(1);
+}
+
+static void xen_apic_wait_icr_idle(void)
+{
+        return;
+}
+
+static u32 xen_safe_apic_wait_icr_idle(void)
+{
+        return 0;
+}
+
+static void set_xen_basic_apic_ops(void)
+{
+	apic->read = xen_apic_read;
+	apic->write = xen_apic_write;
+	apic->icr_read = xen_apic_icr_read;
+	apic->icr_write = xen_apic_icr_write;
+	apic->wait_icr_idle = xen_apic_wait_icr_idle;
+	apic->safe_wait_icr_idle = xen_safe_apic_wait_icr_idle;
+	apic->set_apic_id = xen_set_apic_id;
+	apic->get_apic_id = xen_get_apic_id;
+}
+
+#endif
+
+static void xen_clts(void)
+{
+	struct multicall_space mcs;
+
+	mcs = xen_mc_entry(0);
+
+	MULTI_fpu_taskswitch(mcs.mc, 0);
+
+	xen_mc_issue(PARAVIRT_LAZY_CPU);
+}
+
+static DEFINE_PER_CPU(unsigned long, xen_cr0_value);
+
+static unsigned long xen_read_cr0(void)
+{
+	unsigned long cr0 = this_cpu_read(xen_cr0_value);
+
+	if (unlikely(cr0 == 0)) {
+		cr0 = native_read_cr0();
+		this_cpu_write(xen_cr0_value, cr0);
+	}
+
+	return cr0;
+}
+
+static void xen_write_cr0(unsigned long cr0)
+{
+	struct multicall_space mcs;
+
+	this_cpu_write(xen_cr0_value, cr0);
+
+	/* Only pay attention to cr0.TS; everything else is
+	   ignored. */
+	mcs = xen_mc_entry(0);
+
+	MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0);
+
+	xen_mc_issue(PARAVIRT_LAZY_CPU);
+}
+
+static void xen_write_cr4(unsigned long cr4)
+{
+	cr4 &= ~X86_CR4_PGE;
+	cr4 &= ~X86_CR4_PSE;
+
+	native_write_cr4(cr4);
+}
+
+static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
+{
+	int ret;
+
+	ret = 0;
+
+	switch (msr) {
+#ifdef CONFIG_X86_64
+		unsigned which;
+		u64 base;
+
+	case MSR_FS_BASE:		which = SEGBASE_FS; goto set;
+	case MSR_KERNEL_GS_BASE:	which = SEGBASE_GS_USER; goto set;
+	case MSR_GS_BASE:		which = SEGBASE_GS_KERNEL; goto set;
+
+	set:
+		base = ((u64)high << 32) | low;
+		if (HYPERVISOR_set_segment_base(which, base) != 0)
+			ret = -EIO;
+		break;
+#endif
+
+	case MSR_STAR:
+	case MSR_CSTAR:
+	case MSR_LSTAR:
+	case MSR_SYSCALL_MASK:
+	case MSR_IA32_SYSENTER_CS:
+	case MSR_IA32_SYSENTER_ESP:
+	case MSR_IA32_SYSENTER_EIP:
+		/* Fast syscall setup is all done in hypercalls, so
+		   these are all ignored.  Stub them out here to stop
+		   Xen console noise. */
+		break;
+
+	case MSR_IA32_CR_PAT:
+		if (smp_processor_id() == 0)
+			xen_set_pat(((u64)high << 32) | low);
+		break;
+
+	default:
+		ret = native_write_msr_safe(msr, low, high);
+	}
+
+	return ret;
+}
+
+void xen_setup_shared_info(void)
+{
+	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+		set_fixmap(FIX_PARAVIRT_BOOTMAP,
+			   xen_start_info->shared_info);
+
+		HYPERVISOR_shared_info =
+			(struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP);
+	} else
+		HYPERVISOR_shared_info =
+			(struct shared_info *)__va(xen_start_info->shared_info);
+
+#ifndef CONFIG_SMP
+	/* In UP this is as good a place as any to set up shared info */
+	xen_setup_vcpu_info_placement();
+#endif
+
+	xen_setup_mfn_list_list();
+}
+
+/* This is called once we have the cpu_possible_mask */
+void xen_setup_vcpu_info_placement(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		xen_vcpu_setup(cpu);
+
+	/* xen_vcpu_setup managed to place the vcpu_info within the
+	   percpu area for all cpus, so make use of it */
+	if (have_vcpu_info_placement) {
+		pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct);
+		pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct);
+		pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct);
+		pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct);
+		pv_mmu_ops.read_cr2 = xen_read_cr2_direct;
+	}
+}
+
+static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf,
+			  unsigned long addr, unsigned len)
+{
+	char *start, *end, *reloc;
+	unsigned ret;
+
+	start = end = reloc = NULL;
+
+#define SITE(op, x)							\
+	case PARAVIRT_PATCH(op.x):					\
+	if (have_vcpu_info_placement) {					\
+		start = (char *)xen_##x##_direct;			\
+		end = xen_##x##_direct_end;				\
+		reloc = xen_##x##_direct_reloc;				\
+	}								\
+	goto patch_site
+
+	switch (type) {
+		SITE(pv_irq_ops, irq_enable);
+		SITE(pv_irq_ops, irq_disable);
+		SITE(pv_irq_ops, save_fl);
+		SITE(pv_irq_ops, restore_fl);
+#undef SITE
+
+	patch_site:
+		if (start == NULL || (end-start) > len)
+			goto default_patch;
+
+		ret = paravirt_patch_insns(insnbuf, len, start, end);
+
+		/* Note: because reloc is assigned from something that
+		   appears to be an array, gcc assumes it's non-null,
+		   but doesn't know its relationship with start and
+		   end. */
+		if (reloc > start && reloc < end) {
+			int reloc_off = reloc - start;
+			long *relocp = (long *)(insnbuf + reloc_off);
+			long delta = start - (char *)addr;
+
+			*relocp += delta;
+		}
+		break;
+
+	default_patch:
+	default:
+		ret = paravirt_patch_default(type, clobbers, insnbuf,
+					     addr, len);
+		break;
+	}
+
+	return ret;
+}
+
+static const struct pv_info xen_info __initconst = {
+	.paravirt_enabled = 1,
+	.shared_kernel_pmd = 0,
+
+#ifdef CONFIG_X86_64
+	.extra_user_64bit_cs = FLAT_USER_CS64,
+#endif
+
+	.name = "Xen",
+};
+
+static const struct pv_init_ops xen_init_ops __initconst = {
+	.patch = xen_patch,
+};
+
+static const struct pv_cpu_ops xen_cpu_ops __initconst = {
+	.cpuid = xen_cpuid,
+
+	.set_debugreg = xen_set_debugreg,
+	.get_debugreg = xen_get_debugreg,
+
+	.clts = xen_clts,
+
+	.read_cr0 = xen_read_cr0,
+	.write_cr0 = xen_write_cr0,
+
+	.read_cr4 = native_read_cr4,
+	.read_cr4_safe = native_read_cr4_safe,
+	.write_cr4 = xen_write_cr4,
+
+	.wbinvd = native_wbinvd,
+
+	.read_msr = native_read_msr_safe,
+	.rdmsr_regs = native_rdmsr_safe_regs,
+	.write_msr = xen_write_msr_safe,
+	.wrmsr_regs = native_wrmsr_safe_regs,
+
+	.read_tsc = native_read_tsc,
+	.read_pmc = native_read_pmc,
+
+	.iret = xen_iret,
+	.irq_enable_sysexit = xen_sysexit,
+#ifdef CONFIG_X86_64
+	.usergs_sysret32 = xen_sysret32,
+	.usergs_sysret64 = xen_sysret64,
+#endif
+
+	.load_tr_desc = paravirt_nop,
+	.set_ldt = xen_set_ldt,
+	.load_gdt = xen_load_gdt,
+	.load_idt = xen_load_idt,
+	.load_tls = xen_load_tls,
+#ifdef CONFIG_X86_64
+	.load_gs_index = xen_load_gs_index,
+#endif
+
+	.alloc_ldt = xen_alloc_ldt,
+	.free_ldt = xen_free_ldt,
+
+	.store_gdt = native_store_gdt,
+	.store_idt = native_store_idt,
+	.store_tr = xen_store_tr,
+
+	.write_ldt_entry = xen_write_ldt_entry,
+	.write_gdt_entry = xen_write_gdt_entry,
+	.write_idt_entry = xen_write_idt_entry,
+	.load_sp0 = xen_load_sp0,
+
+	.set_iopl_mask = xen_set_iopl_mask,
+	.io_delay = xen_io_delay,
+
+	/* Xen takes care of %gs when switching to usermode for us */
+	.swapgs = paravirt_nop,
+
+	.start_context_switch = paravirt_start_context_switch,
+	.end_context_switch = xen_end_context_switch,
+};
+
+static const struct pv_apic_ops xen_apic_ops __initconst = {
+#ifdef CONFIG_X86_LOCAL_APIC
+	.startup_ipi_hook = paravirt_nop,
+#endif
+};
+
+static void xen_reboot(int reason)
+{
+	struct sched_shutdown r = { .reason = reason };
+
+	if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r))
+		BUG();
+}
+
+static void xen_restart(char *msg)
+{
+	xen_reboot(SHUTDOWN_reboot);
+}
+
+static void xen_emergency_restart(void)
+{
+	xen_reboot(SHUTDOWN_reboot);
+}
+
+static void xen_machine_halt(void)
+{
+	xen_reboot(SHUTDOWN_poweroff);
+}
+
+static void xen_machine_power_off(void)
+{
+	if (pm_power_off)
+		pm_power_off();
+	xen_reboot(SHUTDOWN_poweroff);
+}
+
+static void xen_crash_shutdown(struct pt_regs *regs)
+{
+	xen_reboot(SHUTDOWN_crash);
+}
+
+static int
+xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr)
+{
+	xen_reboot(SHUTDOWN_crash);
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block xen_panic_block = {
+	.notifier_call= xen_panic_event,
+};
+
+int xen_panic_handler_init(void)
+{
+	atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block);
+	return 0;
+}
+
+static const struct machine_ops xen_machine_ops __initconst = {
+	.restart = xen_restart,
+	.halt = xen_machine_halt,
+	.power_off = xen_machine_power_off,
+	.shutdown = xen_machine_halt,
+	.crash_shutdown = xen_crash_shutdown,
+	.emergency_restart = xen_emergency_restart,
+};
+
+/*
+ * Set up the GDT and segment registers for -fstack-protector.  Until
+ * we do this, we have to be careful not to call any stack-protected
+ * function, which is most of the kernel.
+ */
+static void __init xen_setup_stackprotector(void)
+{
+	pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot;
+	pv_cpu_ops.load_gdt = xen_load_gdt_boot;
+
+	setup_stack_canary_segment(0);
+	switch_to_new_gdt(0);
+
+	pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry;
+	pv_cpu_ops.load_gdt = xen_load_gdt;
+}
+
+/* First C function to be called on Xen boot */
+asmlinkage void __init xen_start_kernel(void)
+{
+	struct physdev_set_iopl set_iopl;
+	int rc;
+	pgd_t *pgd;
+
+	if (!xen_start_info)
+		return;
+
+	xen_domain_type = XEN_PV_DOMAIN;
+
+	xen_setup_machphys_mapping();
+
+	/* Install Xen paravirt ops */
+	pv_info = xen_info;
+	pv_init_ops = xen_init_ops;
+	pv_cpu_ops = xen_cpu_ops;
+	pv_apic_ops = xen_apic_ops;
+
+	x86_init.resources.memory_setup = xen_memory_setup;
+	x86_init.oem.arch_setup = xen_arch_setup;
+	x86_init.oem.banner = xen_banner;
+
+	xen_init_time_ops();
+
+	/*
+	 * Set up some pagetable state before starting to set any ptes.
+	 */
+
+	xen_init_mmu_ops();
+
+	/* Prevent unwanted bits from being set in PTEs. */
+	__supported_pte_mask &= ~_PAGE_GLOBAL;
+#if 0
+	if (!xen_initial_domain())
+#endif
+		__supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD);
+
+	__supported_pte_mask |= _PAGE_IOMAP;
+
+	/*
+	 * Prevent page tables from being allocated in highmem, even
+	 * if CONFIG_HIGHPTE is enabled.
+	 */
+	__userpte_alloc_gfp &= ~__GFP_HIGHMEM;
+
+	/* Work out if we support NX */
+	x86_configure_nx();
+
+	xen_setup_features();
+
+	/* Get mfn list */
+	if (!xen_feature(XENFEAT_auto_translated_physmap))
+		xen_build_dynamic_phys_to_machine();
+
+	/*
+	 * Set up kernel GDT and segment registers, mainly so that
+	 * -fstack-protector code can be executed.
+	 */
+	xen_setup_stackprotector();
+
+	xen_init_irq_ops();
+	xen_init_cpuid_mask();
+
+#ifdef CONFIG_X86_LOCAL_APIC
+	/*
+	 * set up the basic apic ops.
+	 */
+	set_xen_basic_apic_ops();
+#endif
+
+	if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) {
+		pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start;
+		pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit;
+	}
+
+	machine_ops = xen_machine_ops;
+
+	/*
+	 * The only reliable way to retain the initial address of the
+	 * percpu gdt_page is to remember it here, so we can go and
+	 * mark it RW later, when the initial percpu area is freed.
+	 */
+	xen_initial_gdt = &per_cpu(gdt_page, 0);
+
+	xen_smp_init();
+
+#ifdef CONFIG_ACPI_NUMA
+	/*
+	 * The pages we from Xen are not related to machine pages, so
+	 * any NUMA information the kernel tries to get from ACPI will
+	 * be meaningless.  Prevent it from trying.
+	 */
+	acpi_numa = -1;
+#endif
+
+	pgd = (pgd_t *)xen_start_info->pt_base;
+
+	/* Don't do the full vcpu_info placement stuff until we have a
+	   possible map and a non-dummy shared_info. */
+	per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
+
+	local_irq_disable();
+	early_boot_irqs_disabled = true;
+
+	xen_raw_console_write("mapping kernel into physical memory\n");
+	pgd = xen_setup_kernel_pagetable(pgd, xen_start_info->nr_pages);
+	xen_ident_map_ISA();
+
+	/* Allocate and initialize top and mid mfn levels for p2m structure */
+	xen_build_mfn_list_list();
+
+	/* keep using Xen gdt for now; no urgent need to change it */
+
+#ifdef CONFIG_X86_32
+	pv_info.kernel_rpl = 1;
+	if (xen_feature(XENFEAT_supervisor_mode_kernel))
+		pv_info.kernel_rpl = 0;
+#else
+	pv_info.kernel_rpl = 0;
+#endif
+	/* set the limit of our address space */
+	xen_reserve_top();
+
+	/* We used to do this in xen_arch_setup, but that is too late on AMD
+	 * were early_cpu_init (run before ->arch_setup()) calls early_amd_init
+	 * which pokes 0xcf8 port.
+	 */
+	set_iopl.iopl = 1;
+	rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
+	if (rc != 0)
+		xen_raw_printk("physdev_op failed %d\n", rc);
+
+#ifdef CONFIG_X86_32
+	/* set up basic CPUID stuff */
+	cpu_detect(&new_cpu_data);
+	new_cpu_data.hard_math = 1;
+	new_cpu_data.wp_works_ok = 1;
+	new_cpu_data.x86_capability[0] = cpuid_edx(1);
+#endif
+
+	/* Poke various useful things into boot_params */
+	boot_params.hdr.type_of_loader = (9 << 4) | 0;
+	boot_params.hdr.ramdisk_image = xen_start_info->mod_start
+		? __pa(xen_start_info->mod_start) : 0;
+	boot_params.hdr.ramdisk_size = xen_start_info->mod_len;
+	boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line);
+
+	if (!xen_initial_domain()) {
+		add_preferred_console("xenboot", 0, NULL);
+		add_preferred_console("tty", 0, NULL);
+		add_preferred_console("hvc", 0, NULL);
+		if (pci_xen)
+			x86_init.pci.arch_init = pci_xen_init;
+	} else {
+		const struct dom0_vga_console_info *info =
+			(void *)((char *)xen_start_info +
+				 xen_start_info->console.dom0.info_off);
+
+		xen_init_vga(info, xen_start_info->console.dom0.info_size);
+		xen_start_info->console.domU.mfn = 0;
+		xen_start_info->console.domU.evtchn = 0;
+
+		/* Make sure ACS will be enabled */
+		pci_request_acs();
+	}
+#ifdef CONFIG_PCI
+	/* PCI BIOS service won't work from a PV guest. */
+	pci_probe &= ~PCI_PROBE_BIOS;
+#endif
+	xen_raw_console_write("about to get started...\n");
+
+	xen_setup_runstate_info(0);
+
+	/* Start the world */
+#ifdef CONFIG_X86_32
+	i386_start_kernel();
+#else
+	x86_64_start_reservations((char *)__pa_symbol(&boot_params));
+#endif
+}
+
+static int init_hvm_pv_info(int *major, int *minor)
+{
+	uint32_t eax, ebx, ecx, edx, pages, msr, base;
+	u64 pfn;
+
+	base = xen_cpuid_base();
+	cpuid(base + 1, &eax, &ebx, &ecx, &edx);
+
+	*major = eax >> 16;
+	*minor = eax & 0xffff;
+	printk(KERN_INFO "Xen version %d.%d.\n", *major, *minor);
+
+	cpuid(base + 2, &pages, &msr, &ecx, &edx);
+
+	pfn = __pa(hypercall_page);
+	wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
+
+	xen_setup_features();
+
+	pv_info.name = "Xen HVM";
+
+	xen_domain_type = XEN_HVM_DOMAIN;
+
+	return 0;
+}
+
+void __ref xen_hvm_init_shared_info(void)
+{
+	int cpu;
+	struct xen_add_to_physmap xatp;
+	static struct shared_info *shared_info_page = 0;
+
+	if (!shared_info_page)
+		shared_info_page = (struct shared_info *)
+			extend_brk(PAGE_SIZE, PAGE_SIZE);
+	xatp.domid = DOMID_SELF;
+	xatp.idx = 0;
+	xatp.space = XENMAPSPACE_shared_info;
+	xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT;
+	if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
+		BUG();
+
+	HYPERVISOR_shared_info = (struct shared_info *)shared_info_page;
+
+	/* xen_vcpu is a pointer to the vcpu_info struct in the shared_info
+	 * page, we use it in the event channel upcall and in some pvclock
+	 * related functions. We don't need the vcpu_info placement
+	 * optimizations because we don't use any pv_mmu or pv_irq op on
+	 * HVM.
+	 * When xen_hvm_init_shared_info is run at boot time only vcpu 0 is
+	 * online but xen_hvm_init_shared_info is run at resume time too and
+	 * in that case multiple vcpus might be online. */
+	for_each_online_cpu(cpu) {
+		per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
+	}
+}
+
+#ifdef CONFIG_XEN_PVHVM
+static int __cpuinit xen_hvm_cpu_notify(struct notifier_block *self,
+				    unsigned long action, void *hcpu)
+{
+	int cpu = (long)hcpu;
+	switch (action) {
+	case CPU_UP_PREPARE:
+		xen_vcpu_setup(cpu);
+		if (xen_have_vector_callback)
+			xen_init_lock_cpu(cpu);
+		break;
+	default:
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block xen_hvm_cpu_notifier __cpuinitdata = {
+	.notifier_call	= xen_hvm_cpu_notify,
+};
+
+static void __init xen_hvm_guest_init(void)
+{
+	int r;
+	int major, minor;
+
+	r = init_hvm_pv_info(&major, &minor);
+	if (r < 0)
+		return;
+
+	xen_hvm_init_shared_info();
+
+	if (xen_feature(XENFEAT_hvm_callback_vector))
+		xen_have_vector_callback = 1;
+	xen_hvm_smp_init();
+	register_cpu_notifier(&xen_hvm_cpu_notifier);
+	xen_unplug_emulated_devices();
+	x86_init.irqs.intr_init = xen_init_IRQ;
+	xen_hvm_init_time_ops();
+	xen_hvm_init_mmu_ops();
+}
+
+static bool __init xen_hvm_platform(void)
+{
+	if (xen_pv_domain())
+		return false;
+
+	if (!xen_cpuid_base())
+		return false;
+
+	return true;
+}
+
+bool xen_hvm_need_lapic(void)
+{
+	if (xen_pv_domain())
+		return false;
+	if (!xen_hvm_domain())
+		return false;
+	if (xen_feature(XENFEAT_hvm_pirqs) && xen_have_vector_callback)
+		return false;
+	return true;
+}
+EXPORT_SYMBOL_GPL(xen_hvm_need_lapic);
+
+const struct hypervisor_x86 x86_hyper_xen_hvm __refconst = {
+	.name			= "Xen HVM",
+	.detect			= xen_hvm_platform,
+	.init_platform		= xen_hvm_guest_init,
+};
+EXPORT_SYMBOL(x86_hyper_xen_hvm);
+#endif
diff --git a/arch/x86/xen/grant-table.c b/arch/x86/xen/grant-table.c
new file mode 100644
index 00000000..3a5f55d5
--- /dev/null
+++ b/arch/x86/xen/grant-table.c
@@ -0,0 +1,127 @@
+/******************************************************************************
+ * grant_table.c
+ * x86 specific part
+ *
+ * Granting foreign access to our memory reservation.
+ *
+ * Copyright (c) 2005-2006, Christopher Clark
+ * Copyright (c) 2004-2005, K A Fraser
+ * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
+ *                    VA Linux Systems Japan. Split out x86 specific part.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+
+#include <xen/interface/xen.h>
+#include <xen/page.h>
+#include <xen/grant_table.h>
+
+#include <asm/pgtable.h>
+
+static int map_pte_fn(pte_t *pte, struct page *pmd_page,
+		      unsigned long addr, void *data)
+{
+	unsigned long **frames = (unsigned long **)data;
+
+	set_pte_at(&init_mm, addr, pte, mfn_pte((*frames)[0], PAGE_KERNEL));
+	(*frames)++;
+	return 0;
+}
+
+/*
+ * This function is used to map shared frames to store grant status. It is
+ * different from map_pte_fn above, the frames type here is uint64_t.
+ */
+static int map_pte_fn_status(pte_t *pte, struct page *pmd_page,
+			     unsigned long addr, void *data)
+{
+	uint64_t **frames = (uint64_t **)data;
+
+	set_pte_at(&init_mm, addr, pte, mfn_pte((*frames)[0], PAGE_KERNEL));
+	(*frames)++;
+	return 0;
+}
+
+static int unmap_pte_fn(pte_t *pte, struct page *pmd_page,
+			unsigned long addr, void *data)
+{
+
+	set_pte_at(&init_mm, addr, pte, __pte(0));
+	return 0;
+}
+
+int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
+			   unsigned long max_nr_gframes,
+			   void **__shared)
+{
+	int rc;
+	void *shared = *__shared;
+
+	if (shared == NULL) {
+		struct vm_struct *area =
+			alloc_vm_area(PAGE_SIZE * max_nr_gframes, NULL);
+		BUG_ON(area == NULL);
+		shared = area->addr;
+		*__shared = shared;
+	}
+
+	rc = apply_to_page_range(&init_mm, (unsigned long)shared,
+				 PAGE_SIZE * nr_gframes,
+				 map_pte_fn, &frames);
+	return rc;
+}
+
+int arch_gnttab_map_status(uint64_t *frames, unsigned long nr_gframes,
+			   unsigned long max_nr_gframes,
+			   grant_status_t **__shared)
+{
+	int rc;
+	grant_status_t *shared = *__shared;
+
+	if (shared == NULL) {
+		/* No need to pass in PTE as we are going to do it
+		 * in apply_to_page_range anyhow. */
+		struct vm_struct *area =
+			alloc_vm_area(PAGE_SIZE * max_nr_gframes, NULL);
+		BUG_ON(area == NULL);
+		shared = area->addr;
+		*__shared = shared;
+	}
+
+	rc = apply_to_page_range(&init_mm, (unsigned long)shared,
+				 PAGE_SIZE * nr_gframes,
+				 map_pte_fn_status, &frames);
+	return rc;
+}
+
+void arch_gnttab_unmap(void *shared, unsigned long nr_gframes)
+{
+	apply_to_page_range(&init_mm, (unsigned long)shared,
+			    PAGE_SIZE * nr_gframes, unmap_pte_fn, NULL);
+}
diff --git a/arch/x86/xen/irq.c b/arch/x86/xen/irq.c
new file mode 100644
index 00000000..15733765
--- /dev/null
+++ b/arch/x86/xen/irq.c
@@ -0,0 +1,133 @@
+#include <linux/hardirq.h>
+
+#include <asm/x86_init.h>
+
+#include <xen/interface/xen.h>
+#include <xen/interface/sched.h>
+#include <xen/interface/vcpu.h>
+
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+
+#include "xen-ops.h"
+
+/*
+ * Force a proper event-channel callback from Xen after clearing the
+ * callback mask. We do this in a very simple manner, by making a call
+ * down into Xen. The pending flag will be checked by Xen on return.
+ */
+void xen_force_evtchn_callback(void)
+{
+	(void)HYPERVISOR_xen_version(0, NULL);
+}
+
+static unsigned long xen_save_fl(void)
+{
+	struct vcpu_info *vcpu;
+	unsigned long flags;
+
+	vcpu = this_cpu_read(xen_vcpu);
+
+	/* flag has opposite sense of mask */
+	flags = !vcpu->evtchn_upcall_mask;
+
+	/* convert to IF type flag
+	   -0 -> 0x00000000
+	   -1 -> 0xffffffff
+	*/
+	return (-flags) & X86_EFLAGS_IF;
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_save_fl);
+
+static void xen_restore_fl(unsigned long flags)
+{
+	struct vcpu_info *vcpu;
+
+	/* convert from IF type flag */
+	flags = !(flags & X86_EFLAGS_IF);
+
+	/* There's a one instruction preempt window here.  We need to
+	   make sure we're don't switch CPUs between getting the vcpu
+	   pointer and updating the mask. */
+	preempt_disable();
+	vcpu = this_cpu_read(xen_vcpu);
+	vcpu->evtchn_upcall_mask = flags;
+	preempt_enable_no_resched();
+
+	/* Doesn't matter if we get preempted here, because any
+	   pending event will get dealt with anyway. */
+
+	if (flags == 0) {
+		preempt_check_resched();
+		barrier(); /* unmask then check (avoid races) */
+		if (unlikely(vcpu->evtchn_upcall_pending))
+			xen_force_evtchn_callback();
+	}
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_restore_fl);
+
+static void xen_irq_disable(void)
+{
+	/* There's a one instruction preempt window here.  We need to
+	   make sure we're don't switch CPUs between getting the vcpu
+	   pointer and updating the mask. */
+	preempt_disable();
+	this_cpu_read(xen_vcpu)->evtchn_upcall_mask = 1;
+	preempt_enable_no_resched();
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_irq_disable);
+
+static void xen_irq_enable(void)
+{
+	struct vcpu_info *vcpu;
+
+	/* We don't need to worry about being preempted here, since
+	   either a) interrupts are disabled, so no preemption, or b)
+	   the caller is confused and is trying to re-enable interrupts
+	   on an indeterminate processor. */
+
+	vcpu = this_cpu_read(xen_vcpu);
+	vcpu->evtchn_upcall_mask = 0;
+
+	/* Doesn't matter if we get preempted here, because any
+	   pending event will get dealt with anyway. */
+
+	barrier(); /* unmask then check (avoid races) */
+	if (unlikely(vcpu->evtchn_upcall_pending))
+		xen_force_evtchn_callback();
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_irq_enable);
+
+static void xen_safe_halt(void)
+{
+	/* Blocking includes an implicit local_irq_enable(). */
+	if (HYPERVISOR_sched_op(SCHEDOP_block, NULL) != 0)
+		BUG();
+}
+
+static void xen_halt(void)
+{
+	if (irqs_disabled())
+		HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
+	else
+		xen_safe_halt();
+}
+
+static const struct pv_irq_ops xen_irq_ops __initconst = {
+	.save_fl = PV_CALLEE_SAVE(xen_save_fl),
+	.restore_fl = PV_CALLEE_SAVE(xen_restore_fl),
+	.irq_disable = PV_CALLEE_SAVE(xen_irq_disable),
+	.irq_enable = PV_CALLEE_SAVE(xen_irq_enable),
+
+	.safe_halt = xen_safe_halt,
+	.halt = xen_halt,
+#ifdef CONFIG_X86_64
+	.adjust_exception_frame = xen_adjust_exception_frame,
+#endif
+};
+
+void __init xen_init_irq_ops(void)
+{
+	pv_irq_ops = xen_irq_ops;
+	x86_init.irqs.intr_init = xen_init_IRQ;
+}
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
new file mode 100644
index 00000000..69f58576
--- /dev/null
+++ b/arch/x86/xen/mmu.c
@@ -0,0 +1,2371 @@
+/*
+ * Xen mmu operations
+ *
+ * This file contains the various mmu fetch and update operations.
+ * The most important job they must perform is the mapping between the
+ * domain's pfn and the overall machine mfns.
+ *
+ * Xen allows guests to directly update the pagetable, in a controlled
+ * fashion.  In other words, the guest modifies the same pagetable
+ * that the CPU actually uses, which eliminates the overhead of having
+ * a separate shadow pagetable.
+ *
+ * In order to allow this, it falls on the guest domain to map its
+ * notion of a "physical" pfn - which is just a domain-local linear
+ * address - into a real "machine address" which the CPU's MMU can
+ * use.
+ *
+ * A pgd_t/pmd_t/pte_t will typically contain an mfn, and so can be
+ * inserted directly into the pagetable.  When creating a new
+ * pte/pmd/pgd, it converts the passed pfn into an mfn.  Conversely,
+ * when reading the content back with __(pgd|pmd|pte)_val, it converts
+ * the mfn back into a pfn.
+ *
+ * The other constraint is that all pages which make up a pagetable
+ * must be mapped read-only in the guest.  This prevents uncontrolled
+ * guest updates to the pagetable.  Xen strictly enforces this, and
+ * will disallow any pagetable update which will end up mapping a
+ * pagetable page RW, and will disallow using any writable page as a
+ * pagetable.
+ *
+ * Naively, when loading %cr3 with the base of a new pagetable, Xen
+ * would need to validate the whole pagetable before going on.
+ * Naturally, this is quite slow.  The solution is to "pin" a
+ * pagetable, which enforces all the constraints on the pagetable even
+ * when it is not actively in use.  This menas that Xen can be assured
+ * that it is still valid when you do load it into %cr3, and doesn't
+ * need to revalidate it.
+ *
+ * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
+ */
+#include <linux/sched.h>
+#include <linux/highmem.h>
+#include <linux/debugfs.h>
+#include <linux/bug.h>
+#include <linux/vmalloc.h>
+#include <linux/module.h>
+#include <linux/gfp.h>
+#include <linux/memblock.h>
+#include <linux/seq_file.h>
+
+#include <trace/events/xen.h>
+
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+#include <asm/fixmap.h>
+#include <asm/mmu_context.h>
+#include <asm/setup.h>
+#include <asm/paravirt.h>
+#include <asm/e820.h>
+#include <asm/linkage.h>
+#include <asm/page.h>
+#include <asm/init.h>
+#include <asm/pat.h>
+#include <asm/smp.h>
+
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+
+#include <xen/xen.h>
+#include <xen/page.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/hvm/hvm_op.h>
+#include <xen/interface/version.h>
+#include <xen/interface/memory.h>
+#include <xen/hvc-console.h>
+
+#include "multicalls.h"
+#include "mmu.h"
+#include "debugfs.h"
+
+/*
+ * Protects atomic reservation decrease/increase against concurrent increases.
+ * Also protects non-atomic updates of current_pages and balloon lists.
+ */
+DEFINE_SPINLOCK(xen_reservation_lock);
+
+/*
+ * Identity map, in addition to plain kernel map.  This needs to be
+ * large enough to allocate page table pages to allocate the rest.
+ * Each page can map 2MB.
+ */
+#define LEVEL1_IDENT_ENTRIES	(PTRS_PER_PTE * 4)
+static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES);
+
+#ifdef CONFIG_X86_64
+/* l3 pud for userspace vsyscall mapping */
+static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
+#endif /* CONFIG_X86_64 */
+
+/*
+ * Note about cr3 (pagetable base) values:
+ *
+ * xen_cr3 contains the current logical cr3 value; it contains the
+ * last set cr3.  This may not be the current effective cr3, because
+ * its update may be being lazily deferred.  However, a vcpu looking
+ * at its own cr3 can use this value knowing that it everything will
+ * be self-consistent.
+ *
+ * xen_current_cr3 contains the actual vcpu cr3; it is set once the
+ * hypercall to set the vcpu cr3 is complete (so it may be a little
+ * out of date, but it will never be set early).  If one vcpu is
+ * looking at another vcpu's cr3 value, it should use this variable.
+ */
+DEFINE_PER_CPU(unsigned long, xen_cr3);	 /* cr3 stored as physaddr */
+DEFINE_PER_CPU(unsigned long, xen_current_cr3);	 /* actual vcpu cr3 */
+
+
+/*
+ * Just beyond the highest usermode address.  STACK_TOP_MAX has a
+ * redzone above it, so round it up to a PGD boundary.
+ */
+#define USER_LIMIT	((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK)
+
+unsigned long arbitrary_virt_to_mfn(void *vaddr)
+{
+	xmaddr_t maddr = arbitrary_virt_to_machine(vaddr);
+
+	return PFN_DOWN(maddr.maddr);
+}
+
+xmaddr_t arbitrary_virt_to_machine(void *vaddr)
+{
+	unsigned long address = (unsigned long)vaddr;
+	unsigned int level;
+	pte_t *pte;
+	unsigned offset;
+
+	/*
+	 * if the PFN is in the linear mapped vaddr range, we can just use
+	 * the (quick) virt_to_machine() p2m lookup
+	 */
+	if (virt_addr_valid(vaddr))
+		return virt_to_machine(vaddr);
+
+	/* otherwise we have to do a (slower) full page-table walk */
+
+	pte = lookup_address(address, &level);
+	BUG_ON(pte == NULL);
+	offset = address & ~PAGE_MASK;
+	return XMADDR(((phys_addr_t)pte_mfn(*pte) << PAGE_SHIFT) + offset);
+}
+EXPORT_SYMBOL_GPL(arbitrary_virt_to_machine);
+
+void make_lowmem_page_readonly(void *vaddr)
+{
+	pte_t *pte, ptev;
+	unsigned long address = (unsigned long)vaddr;
+	unsigned int level;
+
+	pte = lookup_address(address, &level);
+	if (pte == NULL)
+		return;		/* vaddr missing */
+
+	ptev = pte_wrprotect(*pte);
+
+	if (HYPERVISOR_update_va_mapping(address, ptev, 0))
+		BUG();
+}
+
+void make_lowmem_page_readwrite(void *vaddr)
+{
+	pte_t *pte, ptev;
+	unsigned long address = (unsigned long)vaddr;
+	unsigned int level;
+
+	pte = lookup_address(address, &level);
+	if (pte == NULL)
+		return;		/* vaddr missing */
+
+	ptev = pte_mkwrite(*pte);
+
+	if (HYPERVISOR_update_va_mapping(address, ptev, 0))
+		BUG();
+}
+
+
+static bool xen_page_pinned(void *ptr)
+{
+	struct page *page = virt_to_page(ptr);
+
+	return PagePinned(page);
+}
+
+void xen_set_domain_pte(pte_t *ptep, pte_t pteval, unsigned domid)
+{
+	struct multicall_space mcs;
+	struct mmu_update *u;
+
+	trace_xen_mmu_set_domain_pte(ptep, pteval, domid);
+
+	mcs = xen_mc_entry(sizeof(*u));
+	u = mcs.args;
+
+	/* ptep might be kmapped when using 32-bit HIGHPTE */
+	u->ptr = virt_to_machine(ptep).maddr;
+	u->val = pte_val_ma(pteval);
+
+	MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, domid);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+EXPORT_SYMBOL_GPL(xen_set_domain_pte);
+
+static void xen_extend_mmu_update(const struct mmu_update *update)
+{
+	struct multicall_space mcs;
+	struct mmu_update *u;
+
+	mcs = xen_mc_extend_args(__HYPERVISOR_mmu_update, sizeof(*u));
+
+	if (mcs.mc != NULL) {
+		mcs.mc->args[1]++;
+	} else {
+		mcs = __xen_mc_entry(sizeof(*u));
+		MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
+	}
+
+	u = mcs.args;
+	*u = *update;
+}
+
+static void xen_extend_mmuext_op(const struct mmuext_op *op)
+{
+	struct multicall_space mcs;
+	struct mmuext_op *u;
+
+	mcs = xen_mc_extend_args(__HYPERVISOR_mmuext_op, sizeof(*u));
+
+	if (mcs.mc != NULL) {
+		mcs.mc->args[1]++;
+	} else {
+		mcs = __xen_mc_entry(sizeof(*u));
+		MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
+	}
+
+	u = mcs.args;
+	*u = *op;
+}
+
+static void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
+{
+	struct mmu_update u;
+
+	preempt_disable();
+
+	xen_mc_batch();
+
+	/* ptr may be ioremapped for 64-bit pagetable setup */
+	u.ptr = arbitrary_virt_to_machine(ptr).maddr;
+	u.val = pmd_val_ma(val);
+	xen_extend_mmu_update(&u);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+	preempt_enable();
+}
+
+static void xen_set_pmd(pmd_t *ptr, pmd_t val)
+{
+	trace_xen_mmu_set_pmd(ptr, val);
+
+	/* If page is not pinned, we can just update the entry
+	   directly */
+	if (!xen_page_pinned(ptr)) {
+		*ptr = val;
+		return;
+	}
+
+	xen_set_pmd_hyper(ptr, val);
+}
+
+/*
+ * Associate a virtual page frame with a given physical page frame
+ * and protection flags for that frame.
+ */
+void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
+{
+	set_pte_vaddr(vaddr, mfn_pte(mfn, flags));
+}
+
+static bool xen_batched_set_pte(pte_t *ptep, pte_t pteval)
+{
+	struct mmu_update u;
+
+	if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU)
+		return false;
+
+	xen_mc_batch();
+
+	u.ptr = virt_to_machine(ptep).maddr | MMU_NORMAL_PT_UPDATE;
+	u.val = pte_val_ma(pteval);
+	xen_extend_mmu_update(&u);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+	return true;
+}
+
+static inline void __xen_set_pte(pte_t *ptep, pte_t pteval)
+{
+	if (!xen_batched_set_pte(ptep, pteval))
+		native_set_pte(ptep, pteval);
+}
+
+static void xen_set_pte(pte_t *ptep, pte_t pteval)
+{
+	trace_xen_mmu_set_pte(ptep, pteval);
+	__xen_set_pte(ptep, pteval);
+}
+
+static void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
+		    pte_t *ptep, pte_t pteval)
+{
+	trace_xen_mmu_set_pte_at(mm, addr, ptep, pteval);
+	__xen_set_pte(ptep, pteval);
+}
+
+pte_t xen_ptep_modify_prot_start(struct mm_struct *mm,
+				 unsigned long addr, pte_t *ptep)
+{
+	/* Just return the pte as-is.  We preserve the bits on commit */
+	trace_xen_mmu_ptep_modify_prot_start(mm, addr, ptep, *ptep);
+	return *ptep;
+}
+
+void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
+				 pte_t *ptep, pte_t pte)
+{
+	struct mmu_update u;
+
+	trace_xen_mmu_ptep_modify_prot_commit(mm, addr, ptep, pte);
+	xen_mc_batch();
+
+	u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
+	u.val = pte_val_ma(pte);
+	xen_extend_mmu_update(&u);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+
+/* Assume pteval_t is equivalent to all the other *val_t types. */
+static pteval_t pte_mfn_to_pfn(pteval_t val)
+{
+	if (val & _PAGE_PRESENT) {
+		unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
+		unsigned long pfn = mfn_to_pfn(mfn);
+
+		pteval_t flags = val & PTE_FLAGS_MASK;
+		if (unlikely(pfn == ~0))
+			val = flags & ~_PAGE_PRESENT;
+		else
+			val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
+	}
+
+	return val;
+}
+
+static pteval_t pte_pfn_to_mfn(pteval_t val)
+{
+	if (val & _PAGE_PRESENT) {
+		unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
+		pteval_t flags = val & PTE_FLAGS_MASK;
+		unsigned long mfn;
+
+		if (!xen_feature(XENFEAT_auto_translated_physmap))
+			mfn = get_phys_to_machine(pfn);
+		else
+			mfn = pfn;
+		/*
+		 * If there's no mfn for the pfn, then just create an
+		 * empty non-present pte.  Unfortunately this loses
+		 * information about the original pfn, so
+		 * pte_mfn_to_pfn is asymmetric.
+		 */
+		if (unlikely(mfn == INVALID_P2M_ENTRY)) {
+			mfn = 0;
+			flags = 0;
+		} else {
+			/*
+			 * Paramount to do this test _after_ the
+			 * INVALID_P2M_ENTRY as INVALID_P2M_ENTRY &
+			 * IDENTITY_FRAME_BIT resolves to true.
+			 */
+			mfn &= ~FOREIGN_FRAME_BIT;
+			if (mfn & IDENTITY_FRAME_BIT) {
+				mfn &= ~IDENTITY_FRAME_BIT;
+				flags |= _PAGE_IOMAP;
+			}
+		}
+		val = ((pteval_t)mfn << PAGE_SHIFT) | flags;
+	}
+
+	return val;
+}
+
+static pteval_t iomap_pte(pteval_t val)
+{
+	if (val & _PAGE_PRESENT) {
+		unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
+		pteval_t flags = val & PTE_FLAGS_MASK;
+
+		/* We assume the pte frame number is a MFN, so
+		   just use it as-is. */
+		val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
+	}
+
+	return val;
+}
+
+static pteval_t xen_pte_val(pte_t pte)
+{
+	pteval_t pteval = pte.pte;
+#if 0
+	/* If this is a WC pte, convert back from Xen WC to Linux WC */
+	if ((pteval & (_PAGE_PAT | _PAGE_PCD | _PAGE_PWT)) == _PAGE_PAT) {
+		WARN_ON(!pat_enabled);
+		pteval = (pteval & ~_PAGE_PAT) | _PAGE_PWT;
+	}
+#endif
+	if (xen_initial_domain() && (pteval & _PAGE_IOMAP))
+		return pteval;
+
+	return pte_mfn_to_pfn(pteval);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
+
+static pgdval_t xen_pgd_val(pgd_t pgd)
+{
+	return pte_mfn_to_pfn(pgd.pgd);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val);
+
+/*
+ * Xen's PAT setup is part of its ABI, though I assume entries 6 & 7
+ * are reserved for now, to correspond to the Intel-reserved PAT
+ * types.
+ *
+ * We expect Linux's PAT set as follows:
+ *
+ * Idx  PTE flags        Linux    Xen    Default
+ * 0                     WB       WB     WB
+ * 1            PWT      WC       WT     WT
+ * 2        PCD          UC-      UC-    UC-
+ * 3        PCD PWT      UC       UC     UC
+ * 4    PAT              WB       WC     WB
+ * 5    PAT     PWT      WC       WP     WT
+ * 6    PAT PCD          UC-      UC     UC-
+ * 7    PAT PCD PWT      UC       UC     UC
+ */
+
+void xen_set_pat(u64 pat)
+{
+	/* We expect Linux to use a PAT setting of
+	 * UC UC- WC WB (ignoring the PAT flag) */
+	WARN_ON(pat != 0x0007010600070106ull);
+}
+
+static pte_t xen_make_pte(pteval_t pte)
+{
+	phys_addr_t addr = (pte & PTE_PFN_MASK);
+#if 0
+	/* If Linux is trying to set a WC pte, then map to the Xen WC.
+	 * If _PAGE_PAT is set, then it probably means it is really
+	 * _PAGE_PSE, so avoid fiddling with the PAT mapping and hope
+	 * things work out OK...
+	 *
+	 * (We should never see kernel mappings with _PAGE_PSE set,
+	 * but we could see hugetlbfs mappings, I think.).
+	 */
+	if (pat_enabled && !WARN_ON(pte & _PAGE_PAT)) {
+		if ((pte & (_PAGE_PCD | _PAGE_PWT)) == _PAGE_PWT)
+			pte = (pte & ~(_PAGE_PCD | _PAGE_PWT)) | _PAGE_PAT;
+	}
+#endif
+	/*
+	 * Unprivileged domains are allowed to do IOMAPpings for
+	 * PCI passthrough, but not map ISA space.  The ISA
+	 * mappings are just dummy local mappings to keep other
+	 * parts of the kernel happy.
+	 */
+	if (unlikely(pte & _PAGE_IOMAP) &&
+	    (xen_initial_domain() || addr >= ISA_END_ADDRESS)) {
+		pte = iomap_pte(pte);
+	} else {
+		pte &= ~_PAGE_IOMAP;
+		pte = pte_pfn_to_mfn(pte);
+	}
+
+	return native_make_pte(pte);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);
+
+static pgd_t xen_make_pgd(pgdval_t pgd)
+{
+	pgd = pte_pfn_to_mfn(pgd);
+	return native_make_pgd(pgd);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_make_pgd);
+
+static pmdval_t xen_pmd_val(pmd_t pmd)
+{
+	return pte_mfn_to_pfn(pmd.pmd);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_pmd_val);
+
+static void xen_set_pud_hyper(pud_t *ptr, pud_t val)
+{
+	struct mmu_update u;
+
+	preempt_disable();
+
+	xen_mc_batch();
+
+	/* ptr may be ioremapped for 64-bit pagetable setup */
+	u.ptr = arbitrary_virt_to_machine(ptr).maddr;
+	u.val = pud_val_ma(val);
+	xen_extend_mmu_update(&u);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+	preempt_enable();
+}
+
+static void xen_set_pud(pud_t *ptr, pud_t val)
+{
+	trace_xen_mmu_set_pud(ptr, val);
+
+	/* If page is not pinned, we can just update the entry
+	   directly */
+	if (!xen_page_pinned(ptr)) {
+		*ptr = val;
+		return;
+	}
+
+	xen_set_pud_hyper(ptr, val);
+}
+
+#ifdef CONFIG_X86_PAE
+static void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
+{
+	trace_xen_mmu_set_pte_atomic(ptep, pte);
+	set_64bit((u64 *)ptep, native_pte_val(pte));
+}
+
+static void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+{
+	trace_xen_mmu_pte_clear(mm, addr, ptep);
+	if (!xen_batched_set_pte(ptep, native_make_pte(0)))
+		native_pte_clear(mm, addr, ptep);
+}
+
+static void xen_pmd_clear(pmd_t *pmdp)
+{
+	trace_xen_mmu_pmd_clear(pmdp);
+	set_pmd(pmdp, __pmd(0));
+}
+#endif	/* CONFIG_X86_PAE */
+
+static pmd_t xen_make_pmd(pmdval_t pmd)
+{
+	pmd = pte_pfn_to_mfn(pmd);
+	return native_make_pmd(pmd);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);
+
+#if PAGETABLE_LEVELS == 4
+static pudval_t xen_pud_val(pud_t pud)
+{
+	return pte_mfn_to_pfn(pud.pud);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_pud_val);
+
+static pud_t xen_make_pud(pudval_t pud)
+{
+	pud = pte_pfn_to_mfn(pud);
+
+	return native_make_pud(pud);
+}
+PV_CALLEE_SAVE_REGS_THUNK(xen_make_pud);
+
+static pgd_t *xen_get_user_pgd(pgd_t *pgd)
+{
+	pgd_t *pgd_page = (pgd_t *)(((unsigned long)pgd) & PAGE_MASK);
+	unsigned offset = pgd - pgd_page;
+	pgd_t *user_ptr = NULL;
+
+	if (offset < pgd_index(USER_LIMIT)) {
+		struct page *page = virt_to_page(pgd_page);
+		user_ptr = (pgd_t *)page->private;
+		if (user_ptr)
+			user_ptr += offset;
+	}
+
+	return user_ptr;
+}
+
+static void __xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
+{
+	struct mmu_update u;
+
+	u.ptr = virt_to_machine(ptr).maddr;
+	u.val = pgd_val_ma(val);
+	xen_extend_mmu_update(&u);
+}
+
+/*
+ * Raw hypercall-based set_pgd, intended for in early boot before
+ * there's a page structure.  This implies:
+ *  1. The only existing pagetable is the kernel's
+ *  2. It is always pinned
+ *  3. It has no user pagetable attached to it
+ */
+static void __init xen_set_pgd_hyper(pgd_t *ptr, pgd_t val)
+{
+	preempt_disable();
+
+	xen_mc_batch();
+
+	__xen_set_pgd_hyper(ptr, val);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+	preempt_enable();
+}
+
+static void xen_set_pgd(pgd_t *ptr, pgd_t val)
+{
+	pgd_t *user_ptr = xen_get_user_pgd(ptr);
+
+	trace_xen_mmu_set_pgd(ptr, user_ptr, val);
+
+	/* If page is not pinned, we can just update the entry
+	   directly */
+	if (!xen_page_pinned(ptr)) {
+		*ptr = val;
+		if (user_ptr) {
+			WARN_ON(xen_page_pinned(user_ptr));
+			*user_ptr = val;
+		}
+		return;
+	}
+
+	/* If it's pinned, then we can at least batch the kernel and
+	   user updates together. */
+	xen_mc_batch();
+
+	__xen_set_pgd_hyper(ptr, val);
+	if (user_ptr)
+		__xen_set_pgd_hyper(user_ptr, val);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+#endif	/* PAGETABLE_LEVELS == 4 */
+
+/*
+ * (Yet another) pagetable walker.  This one is intended for pinning a
+ * pagetable.  This means that it walks a pagetable and calls the
+ * callback function on each page it finds making up the page table,
+ * at every level.  It walks the entire pagetable, but it only bothers
+ * pinning pte pages which are below limit.  In the normal case this
+ * will be STACK_TOP_MAX, but at boot we need to pin up to
+ * FIXADDR_TOP.
+ *
+ * For 32-bit the important bit is that we don't pin beyond there,
+ * because then we start getting into Xen's ptes.
+ *
+ * For 64-bit, we must skip the Xen hole in the middle of the address
+ * space, just after the big x86-64 virtual hole.
+ */
+static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
+			  int (*func)(struct mm_struct *mm, struct page *,
+				      enum pt_level),
+			  unsigned long limit)
+{
+	int flush = 0;
+	unsigned hole_low, hole_high;
+	unsigned pgdidx_limit, pudidx_limit, pmdidx_limit;
+	unsigned pgdidx, pudidx, pmdidx;
+
+	/* The limit is the last byte to be touched */
+	limit--;
+	BUG_ON(limit >= FIXADDR_TOP);
+
+	if (xen_feature(XENFEAT_auto_translated_physmap))
+		return 0;
+
+	/*
+	 * 64-bit has a great big hole in the middle of the address
+	 * space, which contains the Xen mappings.  On 32-bit these
+	 * will end up making a zero-sized hole and so is a no-op.
+	 */
+	hole_low = pgd_index(USER_LIMIT);
+	hole_high = pgd_index(PAGE_OFFSET);
+
+	pgdidx_limit = pgd_index(limit);
+#if PTRS_PER_PUD > 1
+	pudidx_limit = pud_index(limit);
+#else
+	pudidx_limit = 0;
+#endif
+#if PTRS_PER_PMD > 1
+	pmdidx_limit = pmd_index(limit);
+#else
+	pmdidx_limit = 0;
+#endif
+
+	for (pgdidx = 0; pgdidx <= pgdidx_limit; pgdidx++) {
+		pud_t *pud;
+
+		if (pgdidx >= hole_low && pgdidx < hole_high)
+			continue;
+
+		if (!pgd_val(pgd[pgdidx]))
+			continue;
+
+		pud = pud_offset(&pgd[pgdidx], 0);
+
+		if (PTRS_PER_PUD > 1) /* not folded */
+			flush |= (*func)(mm, virt_to_page(pud), PT_PUD);
+
+		for (pudidx = 0; pudidx < PTRS_PER_PUD; pudidx++) {
+			pmd_t *pmd;
+
+			if (pgdidx == pgdidx_limit &&
+			    pudidx > pudidx_limit)
+				goto out;
+
+			if (pud_none(pud[pudidx]))
+				continue;
+
+			pmd = pmd_offset(&pud[pudidx], 0);
+
+			if (PTRS_PER_PMD > 1) /* not folded */
+				flush |= (*func)(mm, virt_to_page(pmd), PT_PMD);
+
+			for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++) {
+				struct page *pte;
+
+				if (pgdidx == pgdidx_limit &&
+				    pudidx == pudidx_limit &&
+				    pmdidx > pmdidx_limit)
+					goto out;
+
+				if (pmd_none(pmd[pmdidx]))
+					continue;
+
+				pte = pmd_page(pmd[pmdidx]);
+				flush |= (*func)(mm, pte, PT_PTE);
+			}
+		}
+	}
+
+out:
+	/* Do the top level last, so that the callbacks can use it as
+	   a cue to do final things like tlb flushes. */
+	flush |= (*func)(mm, virt_to_page(pgd), PT_PGD);
+
+	return flush;
+}
+
+static int xen_pgd_walk(struct mm_struct *mm,
+			int (*func)(struct mm_struct *mm, struct page *,
+				    enum pt_level),
+			unsigned long limit)
+{
+	return __xen_pgd_walk(mm, mm->pgd, func, limit);
+}
+
+/* If we're using split pte locks, then take the page's lock and
+   return a pointer to it.  Otherwise return NULL. */
+static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
+{
+	spinlock_t *ptl = NULL;
+
+#if USE_SPLIT_PTLOCKS
+	ptl = __pte_lockptr(page);
+	spin_lock_nest_lock(ptl, &mm->page_table_lock);
+#endif
+
+	return ptl;
+}
+
+static void xen_pte_unlock(void *v)
+{
+	spinlock_t *ptl = v;
+	spin_unlock(ptl);
+}
+
+static void xen_do_pin(unsigned level, unsigned long pfn)
+{
+	struct mmuext_op op;
+
+	op.cmd = level;
+	op.arg1.mfn = pfn_to_mfn(pfn);
+
+	xen_extend_mmuext_op(&op);
+}
+
+static int xen_pin_page(struct mm_struct *mm, struct page *page,
+			enum pt_level level)
+{
+	unsigned pgfl = TestSetPagePinned(page);
+	int flush;
+
+	if (pgfl)
+		flush = 0;		/* already pinned */
+	else if (PageHighMem(page))
+		/* kmaps need flushing if we found an unpinned
+		   highpage */
+		flush = 1;
+	else {
+		void *pt = lowmem_page_address(page);
+		unsigned long pfn = page_to_pfn(page);
+		struct multicall_space mcs = __xen_mc_entry(0);
+		spinlock_t *ptl;
+
+		flush = 0;
+
+		/*
+		 * We need to hold the pagetable lock between the time
+		 * we make the pagetable RO and when we actually pin
+		 * it.  If we don't, then other users may come in and
+		 * attempt to update the pagetable by writing it,
+		 * which will fail because the memory is RO but not
+		 * pinned, so Xen won't do the trap'n'emulate.
+		 *
+		 * If we're using split pte locks, we can't hold the
+		 * entire pagetable's worth of locks during the
+		 * traverse, because we may wrap the preempt count (8
+		 * bits).  The solution is to mark RO and pin each PTE
+		 * page while holding the lock.  This means the number
+		 * of locks we end up holding is never more than a
+		 * batch size (~32 entries, at present).
+		 *
+		 * If we're not using split pte locks, we needn't pin
+		 * the PTE pages independently, because we're
+		 * protected by the overall pagetable lock.
+		 */
+		ptl = NULL;
+		if (level == PT_PTE)
+			ptl = xen_pte_lock(page, mm);
+
+		MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
+					pfn_pte(pfn, PAGE_KERNEL_RO),
+					level == PT_PGD ? UVMF_TLB_FLUSH : 0);
+
+		if (ptl) {
+			xen_do_pin(MMUEXT_PIN_L1_TABLE, pfn);
+
+			/* Queue a deferred unlock for when this batch
+			   is completed. */
+			xen_mc_callback(xen_pte_unlock, ptl);
+		}
+	}
+
+	return flush;
+}
+
+/* This is called just after a mm has been created, but it has not
+   been used yet.  We need to make sure that its pagetable is all
+   read-only, and can be pinned. */
+static void __xen_pgd_pin(struct mm_struct *mm, pgd_t *pgd)
+{
+	trace_xen_mmu_pgd_pin(mm, pgd);
+
+	xen_mc_batch();
+
+	if (__xen_pgd_walk(mm, pgd, xen_pin_page, USER_LIMIT)) {
+		/* re-enable interrupts for flushing */
+		xen_mc_issue(0);
+
+		kmap_flush_unused();
+
+		xen_mc_batch();
+	}
+
+#ifdef CONFIG_X86_64
+	{
+		pgd_t *user_pgd = xen_get_user_pgd(pgd);
+
+		xen_do_pin(MMUEXT_PIN_L4_TABLE, PFN_DOWN(__pa(pgd)));
+
+		if (user_pgd) {
+			xen_pin_page(mm, virt_to_page(user_pgd), PT_PGD);
+			xen_do_pin(MMUEXT_PIN_L4_TABLE,
+				   PFN_DOWN(__pa(user_pgd)));
+		}
+	}
+#else /* CONFIG_X86_32 */
+#ifdef CONFIG_X86_PAE
+	/* Need to make sure unshared kernel PMD is pinnable */
+	xen_pin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
+		     PT_PMD);
+#endif
+	xen_do_pin(MMUEXT_PIN_L3_TABLE, PFN_DOWN(__pa(pgd)));
+#endif /* CONFIG_X86_64 */
+	xen_mc_issue(0);
+}
+
+static void xen_pgd_pin(struct mm_struct *mm)
+{
+	__xen_pgd_pin(mm, mm->pgd);
+}
+
+/*
+ * On save, we need to pin all pagetables to make sure they get their
+ * mfns turned into pfns.  Search the list for any unpinned pgds and pin
+ * them (unpinned pgds are not currently in use, probably because the
+ * process is under construction or destruction).
+ *
+ * Expected to be called in stop_machine() ("equivalent to taking
+ * every spinlock in the system"), so the locking doesn't really
+ * matter all that much.
+ */
+void xen_mm_pin_all(void)
+{
+	struct page *page;
+
+	spin_lock(&pgd_lock);
+
+	list_for_each_entry(page, &pgd_list, lru) {
+		if (!PagePinned(page)) {
+			__xen_pgd_pin(&init_mm, (pgd_t *)page_address(page));
+			SetPageSavePinned(page);
+		}
+	}
+
+	spin_unlock(&pgd_lock);
+}
+
+/*
+ * The init_mm pagetable is really pinned as soon as its created, but
+ * that's before we have page structures to store the bits.  So do all
+ * the book-keeping now.
+ */
+static int __init xen_mark_pinned(struct mm_struct *mm, struct page *page,
+				  enum pt_level level)
+{
+	SetPagePinned(page);
+	return 0;
+}
+
+static void __init xen_mark_init_mm_pinned(void)
+{
+	xen_pgd_walk(&init_mm, xen_mark_pinned, FIXADDR_TOP);
+}
+
+static int xen_unpin_page(struct mm_struct *mm, struct page *page,
+			  enum pt_level level)
+{
+	unsigned pgfl = TestClearPagePinned(page);
+
+	if (pgfl && !PageHighMem(page)) {
+		void *pt = lowmem_page_address(page);
+		unsigned long pfn = page_to_pfn(page);
+		spinlock_t *ptl = NULL;
+		struct multicall_space mcs;
+
+		/*
+		 * Do the converse to pin_page.  If we're using split
+		 * pte locks, we must be holding the lock for while
+		 * the pte page is unpinned but still RO to prevent
+		 * concurrent updates from seeing it in this
+		 * partially-pinned state.
+		 */
+		if (level == PT_PTE) {
+			ptl = xen_pte_lock(page, mm);
+
+			if (ptl)
+				xen_do_pin(MMUEXT_UNPIN_TABLE, pfn);
+		}
+
+		mcs = __xen_mc_entry(0);
+
+		MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
+					pfn_pte(pfn, PAGE_KERNEL),
+					level == PT_PGD ? UVMF_TLB_FLUSH : 0);
+
+		if (ptl) {
+			/* unlock when batch completed */
+			xen_mc_callback(xen_pte_unlock, ptl);
+		}
+	}
+
+	return 0;		/* never need to flush on unpin */
+}
+
+/* Release a pagetables pages back as normal RW */
+static void __xen_pgd_unpin(struct mm_struct *mm, pgd_t *pgd)
+{
+	trace_xen_mmu_pgd_unpin(mm, pgd);
+
+	xen_mc_batch();
+
+	xen_do_pin(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
+
+#ifdef CONFIG_X86_64
+	{
+		pgd_t *user_pgd = xen_get_user_pgd(pgd);
+
+		if (user_pgd) {
+			xen_do_pin(MMUEXT_UNPIN_TABLE,
+				   PFN_DOWN(__pa(user_pgd)));
+			xen_unpin_page(mm, virt_to_page(user_pgd), PT_PGD);
+		}
+	}
+#endif
+
+#ifdef CONFIG_X86_PAE
+	/* Need to make sure unshared kernel PMD is unpinned */
+	xen_unpin_page(mm, pgd_page(pgd[pgd_index(TASK_SIZE)]),
+		       PT_PMD);
+#endif
+
+	__xen_pgd_walk(mm, pgd, xen_unpin_page, USER_LIMIT);
+
+	xen_mc_issue(0);
+}
+
+static void xen_pgd_unpin(struct mm_struct *mm)
+{
+	__xen_pgd_unpin(mm, mm->pgd);
+}
+
+/*
+ * On resume, undo any pinning done at save, so that the rest of the
+ * kernel doesn't see any unexpected pinned pagetables.
+ */
+void xen_mm_unpin_all(void)
+{
+	struct page *page;
+
+	spin_lock(&pgd_lock);
+
+	list_for_each_entry(page, &pgd_list, lru) {
+		if (PageSavePinned(page)) {
+			BUG_ON(!PagePinned(page));
+			__xen_pgd_unpin(&init_mm, (pgd_t *)page_address(page));
+			ClearPageSavePinned(page);
+		}
+	}
+
+	spin_unlock(&pgd_lock);
+}
+
+static void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
+{
+	spin_lock(&next->page_table_lock);
+	xen_pgd_pin(next);
+	spin_unlock(&next->page_table_lock);
+}
+
+static void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
+{
+	spin_lock(&mm->page_table_lock);
+	xen_pgd_pin(mm);
+	spin_unlock(&mm->page_table_lock);
+}
+
+
+#ifdef CONFIG_SMP
+/* Another cpu may still have their %cr3 pointing at the pagetable, so
+   we need to repoint it somewhere else before we can unpin it. */
+static void drop_other_mm_ref(void *info)
+{
+	struct mm_struct *mm = info;
+	struct mm_struct *active_mm;
+
+	active_mm = this_cpu_read(cpu_tlbstate.active_mm);
+
+	if (active_mm == mm && this_cpu_read(cpu_tlbstate.state) != TLBSTATE_OK)
+		leave_mm(smp_processor_id());
+
+	/* If this cpu still has a stale cr3 reference, then make sure
+	   it has been flushed. */
+	if (this_cpu_read(xen_current_cr3) == __pa(mm->pgd))
+		load_cr3(swapper_pg_dir);
+}
+
+static void xen_drop_mm_ref(struct mm_struct *mm)
+{
+	cpumask_var_t mask;
+	unsigned cpu;
+
+	if (current->active_mm == mm) {
+		if (current->mm == mm)
+			load_cr3(swapper_pg_dir);
+		else
+			leave_mm(smp_processor_id());
+	}
+
+	/* Get the "official" set of cpus referring to our pagetable. */
+	if (!alloc_cpumask_var(&mask, GFP_ATOMIC)) {
+		for_each_online_cpu(cpu) {
+			if (!cpumask_test_cpu(cpu, mm_cpumask(mm))
+			    && per_cpu(xen_current_cr3, cpu) != __pa(mm->pgd))
+				continue;
+			smp_call_function_single(cpu, drop_other_mm_ref, mm, 1);
+		}
+		return;
+	}
+	cpumask_copy(mask, mm_cpumask(mm));
+
+	/* It's possible that a vcpu may have a stale reference to our
+	   cr3, because its in lazy mode, and it hasn't yet flushed
+	   its set of pending hypercalls yet.  In this case, we can
+	   look at its actual current cr3 value, and force it to flush
+	   if needed. */
+	for_each_online_cpu(cpu) {
+		if (per_cpu(xen_current_cr3, cpu) == __pa(mm->pgd))
+			cpumask_set_cpu(cpu, mask);
+	}
+
+	if (!cpumask_empty(mask))
+		smp_call_function_many(mask, drop_other_mm_ref, mm, 1);
+	free_cpumask_var(mask);
+}
+#else
+static void xen_drop_mm_ref(struct mm_struct *mm)
+{
+	if (current->active_mm == mm)
+		load_cr3(swapper_pg_dir);
+}
+#endif
+
+/*
+ * While a process runs, Xen pins its pagetables, which means that the
+ * hypervisor forces it to be read-only, and it controls all updates
+ * to it.  This means that all pagetable updates have to go via the
+ * hypervisor, which is moderately expensive.
+ *
+ * Since we're pulling the pagetable down, we switch to use init_mm,
+ * unpin old process pagetable and mark it all read-write, which
+ * allows further operations on it to be simple memory accesses.
+ *
+ * The only subtle point is that another CPU may be still using the
+ * pagetable because of lazy tlb flushing.  This means we need need to
+ * switch all CPUs off this pagetable before we can unpin it.
+ */
+static void xen_exit_mmap(struct mm_struct *mm)
+{
+	get_cpu();		/* make sure we don't move around */
+	xen_drop_mm_ref(mm);
+	put_cpu();
+
+	spin_lock(&mm->page_table_lock);
+
+	/* pgd may not be pinned in the error exit path of execve */
+	if (xen_page_pinned(mm->pgd))
+		xen_pgd_unpin(mm);
+
+	spin_unlock(&mm->page_table_lock);
+}
+
+static void __init xen_pagetable_setup_start(pgd_t *base)
+{
+}
+
+static __init void xen_mapping_pagetable_reserve(u64 start, u64 end)
+{
+	/* reserve the range used */
+	native_pagetable_reserve(start, end);
+
+	/* set as RW the rest */
+	printk(KERN_DEBUG "xen: setting RW the range %llx - %llx\n", end,
+			PFN_PHYS(pgt_buf_top));
+	while (end < PFN_PHYS(pgt_buf_top)) {
+		make_lowmem_page_readwrite(__va(end));
+		end += PAGE_SIZE;
+	}
+}
+
+static void xen_post_allocator_init(void);
+
+static void __init xen_pagetable_setup_done(pgd_t *base)
+{
+	xen_setup_shared_info();
+	xen_post_allocator_init();
+}
+
+static void xen_write_cr2(unsigned long cr2)
+{
+	this_cpu_read(xen_vcpu)->arch.cr2 = cr2;
+}
+
+static unsigned long xen_read_cr2(void)
+{
+	return this_cpu_read(xen_vcpu)->arch.cr2;
+}
+
+unsigned long xen_read_cr2_direct(void)
+{
+	return this_cpu_read(xen_vcpu_info.arch.cr2);
+}
+
+static void xen_flush_tlb(void)
+{
+	struct mmuext_op *op;
+	struct multicall_space mcs;
+
+	trace_xen_mmu_flush_tlb(0);
+
+	preempt_disable();
+
+	mcs = xen_mc_entry(sizeof(*op));
+
+	op = mcs.args;
+	op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
+	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+	preempt_enable();
+}
+
+static void xen_flush_tlb_single(unsigned long addr)
+{
+	struct mmuext_op *op;
+	struct multicall_space mcs;
+
+	trace_xen_mmu_flush_tlb_single(addr);
+
+	preempt_disable();
+
+	mcs = xen_mc_entry(sizeof(*op));
+	op = mcs.args;
+	op->cmd = MMUEXT_INVLPG_LOCAL;
+	op->arg1.linear_addr = addr & PAGE_MASK;
+	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+	preempt_enable();
+}
+
+static void xen_flush_tlb_others(const struct cpumask *cpus,
+				 struct mm_struct *mm, unsigned long va)
+{
+	struct {
+		struct mmuext_op op;
+#ifdef CONFIG_SMP
+		DECLARE_BITMAP(mask, num_processors);
+#else
+		DECLARE_BITMAP(mask, NR_CPUS);
+#endif
+	} *args;
+	struct multicall_space mcs;
+
+	trace_xen_mmu_flush_tlb_others(cpus, mm, va);
+
+	if (cpumask_empty(cpus))
+		return;		/* nothing to do */
+
+	mcs = xen_mc_entry(sizeof(*args));
+	args = mcs.args;
+	args->op.arg2.vcpumask = to_cpumask(args->mask);
+
+	/* Remove us, and any offline CPUS. */
+	cpumask_and(to_cpumask(args->mask), cpus, cpu_online_mask);
+	cpumask_clear_cpu(smp_processor_id(), to_cpumask(args->mask));
+
+	if (va == TLB_FLUSH_ALL) {
+		args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
+	} else {
+		args->op.cmd = MMUEXT_INVLPG_MULTI;
+		args->op.arg1.linear_addr = va;
+	}
+
+	MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+
+static unsigned long xen_read_cr3(void)
+{
+	return this_cpu_read(xen_cr3);
+}
+
+static void set_current_cr3(void *v)
+{
+	this_cpu_write(xen_current_cr3, (unsigned long)v);
+}
+
+static void __xen_write_cr3(bool kernel, unsigned long cr3)
+{
+	struct mmuext_op op;
+	unsigned long mfn;
+
+	trace_xen_mmu_write_cr3(kernel, cr3);
+
+	if (cr3)
+		mfn = pfn_to_mfn(PFN_DOWN(cr3));
+	else
+		mfn = 0;
+
+	WARN_ON(mfn == 0 && kernel);
+
+	op.cmd = kernel ? MMUEXT_NEW_BASEPTR : MMUEXT_NEW_USER_BASEPTR;
+	op.arg1.mfn = mfn;
+
+	xen_extend_mmuext_op(&op);
+
+	if (kernel) {
+		this_cpu_write(xen_cr3, cr3);
+
+		/* Update xen_current_cr3 once the batch has actually
+		   been submitted. */
+		xen_mc_callback(set_current_cr3, (void *)cr3);
+	}
+}
+
+static void xen_write_cr3(unsigned long cr3)
+{
+	BUG_ON(preemptible());
+
+	xen_mc_batch();  /* disables interrupts */
+
+	/* Update while interrupts are disabled, so its atomic with
+	   respect to ipis */
+	this_cpu_write(xen_cr3, cr3);
+
+	__xen_write_cr3(true, cr3);
+
+#ifdef CONFIG_X86_64
+	{
+		pgd_t *user_pgd = xen_get_user_pgd(__va(cr3));
+		if (user_pgd)
+			__xen_write_cr3(false, __pa(user_pgd));
+		else
+			__xen_write_cr3(false, 0);
+	}
+#endif
+
+	xen_mc_issue(PARAVIRT_LAZY_CPU);  /* interrupts restored */
+}
+
+static int xen_pgd_alloc(struct mm_struct *mm)
+{
+	pgd_t *pgd = mm->pgd;
+	int ret = 0;
+
+	BUG_ON(PagePinned(virt_to_page(pgd)));
+
+#ifdef CONFIG_X86_64
+	{
+		struct page *page = virt_to_page(pgd);
+		pgd_t *user_pgd;
+
+		BUG_ON(page->private != 0);
+
+		ret = -ENOMEM;
+
+		user_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+		page->private = (unsigned long)user_pgd;
+
+		if (user_pgd != NULL) {
+			user_pgd[pgd_index(VSYSCALL_START)] =
+				__pgd(__pa(level3_user_vsyscall) | _PAGE_TABLE);
+			ret = 0;
+		}
+
+		BUG_ON(PagePinned(virt_to_page(xen_get_user_pgd(pgd))));
+	}
+#endif
+
+	return ret;
+}
+
+static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
+{
+#ifdef CONFIG_X86_64
+	pgd_t *user_pgd = xen_get_user_pgd(pgd);
+
+	if (user_pgd)
+		free_page((unsigned long)user_pgd);
+#endif
+}
+
+#ifdef CONFIG_X86_32
+static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte)
+{
+	/* If there's an existing pte, then don't allow _PAGE_RW to be set */
+	if (pte_val_ma(*ptep) & _PAGE_PRESENT)
+		pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
+			       pte_val_ma(pte));
+
+	return pte;
+}
+#else /* CONFIG_X86_64 */
+static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte)
+{
+	unsigned long pfn = pte_pfn(pte);
+
+	/*
+	 * If the new pfn is within the range of the newly allocated
+	 * kernel pagetable, and it isn't being mapped into an
+	 * early_ioremap fixmap slot as a freshly allocated page, make sure
+	 * it is RO.
+	 */
+	if (((!is_early_ioremap_ptep(ptep) &&
+			pfn >= pgt_buf_start && pfn < pgt_buf_top)) ||
+			(is_early_ioremap_ptep(ptep) && pfn != (pgt_buf_end - 1)))
+		pte = pte_wrprotect(pte);
+
+	return pte;
+}
+#endif /* CONFIG_X86_64 */
+
+/* Init-time set_pte while constructing initial pagetables, which
+   doesn't allow RO pagetable pages to be remapped RW */
+static void __init xen_set_pte_init(pte_t *ptep, pte_t pte)
+{
+	pte = mask_rw_pte(ptep, pte);
+
+	xen_set_pte(ptep, pte);
+}
+
+static void pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
+{
+	struct mmuext_op op;
+	op.cmd = cmd;
+	op.arg1.mfn = pfn_to_mfn(pfn);
+	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
+		BUG();
+}
+
+/* Early in boot, while setting up the initial pagetable, assume
+   everything is pinned. */
+static void __init xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
+{
+#ifdef CONFIG_FLATMEM
+	BUG_ON(mem_map);	/* should only be used early */
+#endif
+	make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
+	pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
+}
+
+/* Used for pmd and pud */
+static void __init xen_alloc_pmd_init(struct mm_struct *mm, unsigned long pfn)
+{
+#ifdef CONFIG_FLATMEM
+	BUG_ON(mem_map);	/* should only be used early */
+#endif
+	make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
+}
+
+/* Early release_pte assumes that all pts are pinned, since there's
+   only init_mm and anything attached to that is pinned. */
+static void __init xen_release_pte_init(unsigned long pfn)
+{
+	pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
+	make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
+}
+
+static void __init xen_release_pmd_init(unsigned long pfn)
+{
+	make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
+}
+
+static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
+{
+	struct multicall_space mcs;
+	struct mmuext_op *op;
+
+	mcs = __xen_mc_entry(sizeof(*op));
+	op = mcs.args;
+	op->cmd = cmd;
+	op->arg1.mfn = pfn_to_mfn(pfn);
+
+	MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
+}
+
+static inline void __set_pfn_prot(unsigned long pfn, pgprot_t prot)
+{
+	struct multicall_space mcs;
+	unsigned long addr = (unsigned long)__va(pfn << PAGE_SHIFT);
+
+	mcs = __xen_mc_entry(0);
+	MULTI_update_va_mapping(mcs.mc, (unsigned long)addr,
+				pfn_pte(pfn, prot), 0);
+}
+
+/* This needs to make sure the new pte page is pinned iff its being
+   attached to a pinned pagetable. */
+static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn,
+				    unsigned level)
+{
+	bool pinned = PagePinned(virt_to_page(mm->pgd));
+
+	trace_xen_mmu_alloc_ptpage(mm, pfn, level, pinned);
+
+	if (pinned) {
+		struct page *page = pfn_to_page(pfn);
+
+		SetPagePinned(page);
+
+		if (!PageHighMem(page)) {
+			xen_mc_batch();
+
+			__set_pfn_prot(pfn, PAGE_KERNEL_RO);
+
+			if (level == PT_PTE && USE_SPLIT_PTLOCKS)
+				__pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
+
+			xen_mc_issue(PARAVIRT_LAZY_MMU);
+		} else {
+			/* make sure there are no stray mappings of
+			   this page */
+			kmap_flush_unused();
+		}
+	}
+}
+
+static void xen_alloc_pte(struct mm_struct *mm, unsigned long pfn)
+{
+	xen_alloc_ptpage(mm, pfn, PT_PTE);
+}
+
+static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn)
+{
+	xen_alloc_ptpage(mm, pfn, PT_PMD);
+}
+
+/* This should never happen until we're OK to use struct page */
+static inline void xen_release_ptpage(unsigned long pfn, unsigned level)
+{
+	struct page *page = pfn_to_page(pfn);
+	bool pinned = PagePinned(page);
+
+	trace_xen_mmu_release_ptpage(pfn, level, pinned);
+
+	if (pinned) {
+		if (!PageHighMem(page)) {
+			xen_mc_batch();
+
+			if (level == PT_PTE && USE_SPLIT_PTLOCKS)
+				__pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
+
+			__set_pfn_prot(pfn, PAGE_KERNEL);
+
+			xen_mc_issue(PARAVIRT_LAZY_MMU);
+		}
+		ClearPagePinned(page);
+	}
+}
+
+static void xen_release_pte(unsigned long pfn)
+{
+	xen_release_ptpage(pfn, PT_PTE);
+}
+
+static void xen_release_pmd(unsigned long pfn)
+{
+	xen_release_ptpage(pfn, PT_PMD);
+}
+
+#if PAGETABLE_LEVELS == 4
+static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn)
+{
+	xen_alloc_ptpage(mm, pfn, PT_PUD);
+}
+
+static void xen_release_pud(unsigned long pfn)
+{
+	xen_release_ptpage(pfn, PT_PUD);
+}
+#endif
+
+void __init xen_reserve_top(void)
+{
+#ifdef CONFIG_X86_32
+	unsigned long top = HYPERVISOR_VIRT_START;
+	struct xen_platform_parameters pp;
+
+	if (HYPERVISOR_xen_version(XENVER_platform_parameters, &pp) == 0)
+		top = pp.virt_start;
+
+	reserve_top_address(-top);
+#endif	/* CONFIG_X86_32 */
+}
+
+/*
+ * Like __va(), but returns address in the kernel mapping (which is
+ * all we have until the physical memory mapping has been set up.
+ */
+static void *__ka(phys_addr_t paddr)
+{
+#ifdef CONFIG_X86_64
+	return (void *)(paddr + __START_KERNEL_map);
+#else
+	return __va(paddr);
+#endif
+}
+
+/* Convert a machine address to physical address */
+static unsigned long m2p(phys_addr_t maddr)
+{
+	phys_addr_t paddr;
+
+	maddr &= PTE_PFN_MASK;
+	paddr = mfn_to_pfn(maddr >> PAGE_SHIFT) << PAGE_SHIFT;
+
+	return paddr;
+}
+
+/* Convert a machine address to kernel virtual */
+static void *m2v(phys_addr_t maddr)
+{
+	return __ka(m2p(maddr));
+}
+
+/* Set the page permissions on an identity-mapped pages */
+static void set_page_prot(void *addr, pgprot_t prot)
+{
+	unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
+	pte_t pte = pfn_pte(pfn, prot);
+
+	if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, 0))
+		BUG();
+}
+
+static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
+{
+	unsigned pmdidx, pteidx;
+	unsigned ident_pte;
+	unsigned long pfn;
+
+	level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES,
+				      PAGE_SIZE);
+
+	ident_pte = 0;
+	pfn = 0;
+	for (pmdidx = 0; pmdidx < PTRS_PER_PMD && pfn < max_pfn; pmdidx++) {
+		pte_t *pte_page;
+
+		/* Reuse or allocate a page of ptes */
+		if (pmd_present(pmd[pmdidx]))
+			pte_page = m2v(pmd[pmdidx].pmd);
+		else {
+			/* Check for free pte pages */
+			if (ident_pte == LEVEL1_IDENT_ENTRIES)
+				break;
+
+			pte_page = &level1_ident_pgt[ident_pte];
+			ident_pte += PTRS_PER_PTE;
+
+			pmd[pmdidx] = __pmd(__pa(pte_page) | _PAGE_TABLE);
+		}
+
+		/* Install mappings */
+		for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
+			pte_t pte;
+
+#ifdef CONFIG_X86_32
+			if (pfn > max_pfn_mapped)
+				max_pfn_mapped = pfn;
+#endif
+
+			if (!pte_none(pte_page[pteidx]))
+				continue;
+
+			pte = pfn_pte(pfn, PAGE_KERNEL_EXEC);
+			pte_page[pteidx] = pte;
+		}
+	}
+
+	for (pteidx = 0; pteidx < ident_pte; pteidx += PTRS_PER_PTE)
+		set_page_prot(&level1_ident_pgt[pteidx], PAGE_KERNEL_RO);
+
+	set_page_prot(pmd, PAGE_KERNEL_RO);
+}
+
+void __init xen_setup_machphys_mapping(void)
+{
+	struct xen_machphys_mapping mapping;
+
+	if (HYPERVISOR_memory_op(XENMEM_machphys_mapping, &mapping) == 0) {
+		machine_to_phys_mapping = (unsigned long *)mapping.v_start;
+		machine_to_phys_nr = mapping.max_mfn + 1;
+	} else {
+		machine_to_phys_nr = MACH2PHYS_NR_ENTRIES;
+	}
+#ifdef CONFIG_X86_32
+	WARN_ON((machine_to_phys_mapping + (machine_to_phys_nr - 1))
+		< machine_to_phys_mapping);
+#endif
+}
+
+#ifdef CONFIG_X86_64
+static void convert_pfn_mfn(void *v)
+{
+	pte_t *pte = v;
+	int i;
+
+	/* All levels are converted the same way, so just treat them
+	   as ptes. */
+	for (i = 0; i < PTRS_PER_PTE; i++)
+		pte[i] = xen_make_pte(pte[i].pte);
+}
+
+/*
+ * Set up the initial kernel pagetable.
+ *
+ * We can construct this by grafting the Xen provided pagetable into
+ * head_64.S's preconstructed pagetables.  We copy the Xen L2's into
+ * level2_ident_pgt, level2_kernel_pgt and level2_fixmap_pgt.  This
+ * means that only the kernel has a physical mapping to start with -
+ * but that's enough to get __va working.  We need to fill in the rest
+ * of the physical mapping once some sort of allocator has been set
+ * up.
+ */
+pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
+					 unsigned long max_pfn)
+{
+	pud_t *l3;
+	pmd_t *l2;
+
+	/* max_pfn_mapped is the last pfn mapped in the initial memory
+	 * mappings. Considering that on Xen after the kernel mappings we
+	 * have the mappings of some pages that don't exist in pfn space, we
+	 * set max_pfn_mapped to the last real pfn mapped. */
+	max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
+
+	/* Zap identity mapping */
+	init_level4_pgt[0] = __pgd(0);
+
+	/* Pre-constructed entries are in pfn, so convert to mfn */
+	convert_pfn_mfn(init_level4_pgt);
+	convert_pfn_mfn(level3_ident_pgt);
+	convert_pfn_mfn(level3_kernel_pgt);
+
+	l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
+	l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);
+
+	memcpy(level2_ident_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
+	memcpy(level2_kernel_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
+
+	l3 = m2v(pgd[pgd_index(__START_KERNEL_map + PMD_SIZE)].pgd);
+	l2 = m2v(l3[pud_index(__START_KERNEL_map + PMD_SIZE)].pud);
+	memcpy(level2_fixmap_pgt, l2, sizeof(pmd_t) * PTRS_PER_PMD);
+
+	/* Set up identity map */
+	xen_map_identity_early(level2_ident_pgt, max_pfn);
+
+	/* Make pagetable pieces RO */
+	set_page_prot(init_level4_pgt, PAGE_KERNEL_RO);
+	set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
+	set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
+	set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
+	set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
+	set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);
+
+	/* Pin down new L4 */
+	pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
+			  PFN_DOWN(__pa_symbol(init_level4_pgt)));
+
+	/* Unpin Xen-provided one */
+	pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
+
+	/* Switch over */
+	pgd = init_level4_pgt;
+
+	/*
+	 * At this stage there can be no user pgd, and no page
+	 * structure to attach it to, so make sure we just set kernel
+	 * pgd.
+	 */
+	xen_mc_batch();
+	__xen_write_cr3(true, __pa(pgd));
+	xen_mc_issue(PARAVIRT_LAZY_CPU);
+
+	memblock_reserve(__pa(xen_start_info->pt_base),
+			 xen_start_info->nr_pt_frames * PAGE_SIZE);
+
+	return pgd;
+}
+#else	/* !CONFIG_X86_64 */
+static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
+static RESERVE_BRK_ARRAY(pmd_t, swapper_kernel_pmd, PTRS_PER_PMD);
+
+static void __init xen_write_cr3_init(unsigned long cr3)
+{
+	unsigned long pfn = PFN_DOWN(__pa(swapper_pg_dir));
+
+	BUG_ON(read_cr3() != __pa(initial_page_table));
+	BUG_ON(cr3 != __pa(swapper_pg_dir));
+
+	/*
+	 * We are switching to swapper_pg_dir for the first time (from
+	 * initial_page_table) and therefore need to mark that page
+	 * read-only and then pin it.
+	 *
+	 * Xen disallows sharing of kernel PMDs for PAE
+	 * guests. Therefore we must copy the kernel PMD from
+	 * initial_page_table into a new kernel PMD to be used in
+	 * swapper_pg_dir.
+	 */
+	swapper_kernel_pmd =
+		extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
+	memcpy(swapper_kernel_pmd, initial_kernel_pmd,
+	       sizeof(pmd_t) * PTRS_PER_PMD);
+	swapper_pg_dir[KERNEL_PGD_BOUNDARY] =
+		__pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT);
+	set_page_prot(swapper_kernel_pmd, PAGE_KERNEL_RO);
+
+	set_page_prot(swapper_pg_dir, PAGE_KERNEL_RO);
+	xen_write_cr3(cr3);
+	pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, pfn);
+
+	pin_pagetable_pfn(MMUEXT_UNPIN_TABLE,
+			  PFN_DOWN(__pa(initial_page_table)));
+	set_page_prot(initial_page_table, PAGE_KERNEL);
+	set_page_prot(initial_kernel_pmd, PAGE_KERNEL);
+
+	pv_mmu_ops.write_cr3 = &xen_write_cr3;
+}
+
+pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
+					 unsigned long max_pfn)
+{
+	pmd_t *kernel_pmd;
+
+	initial_kernel_pmd =
+		extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
+
+	max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) +
+				  xen_start_info->nr_pt_frames * PAGE_SIZE +
+				  512*1024);
+
+	kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
+	memcpy(initial_kernel_pmd, kernel_pmd, sizeof(pmd_t) * PTRS_PER_PMD);
+
+	xen_map_identity_early(initial_kernel_pmd, max_pfn);
+
+	memcpy(initial_page_table, pgd, sizeof(pgd_t) * PTRS_PER_PGD);
+	initial_page_table[KERNEL_PGD_BOUNDARY] =
+		__pgd(__pa(initial_kernel_pmd) | _PAGE_PRESENT);
+
+	set_page_prot(initial_kernel_pmd, PAGE_KERNEL_RO);
+	set_page_prot(initial_page_table, PAGE_KERNEL_RO);
+	set_page_prot(empty_zero_page, PAGE_KERNEL_RO);
+
+	pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
+
+	pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE,
+			  PFN_DOWN(__pa(initial_page_table)));
+	xen_write_cr3(__pa(initial_page_table));
+
+	memblock_reserve(__pa(xen_start_info->pt_base),
+			 xen_start_info->nr_pt_frames * PAGE_SIZE);
+
+	return initial_page_table;
+}
+#endif	/* CONFIG_X86_64 */
+
+static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss;
+static unsigned char fake_ioapic_mapping[PAGE_SIZE] __page_aligned_bss;
+
+static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
+{
+	pte_t pte;
+
+	phys >>= PAGE_SHIFT;
+
+	switch (idx) {
+	case FIX_BTMAP_END ... FIX_BTMAP_BEGIN:
+#ifdef CONFIG_X86_F00F_BUG
+	case FIX_F00F_IDT:
+#endif
+#ifdef CONFIG_X86_32
+	case FIX_WP_TEST:
+	case FIX_VDSO:
+# ifdef CONFIG_HIGHMEM
+	case FIX_KMAP_BEGIN ... FIX_KMAP_END:
+# endif
+#else
+	case VSYSCALL_LAST_PAGE ... VSYSCALL_FIRST_PAGE:
+	case VVAR_PAGE:
+#endif
+	case FIX_TEXT_POKE0:
+	case FIX_TEXT_POKE1:
+		/* All local page mappings */
+		pte = pfn_pte(phys, prot);
+		break;
+
+#ifdef CONFIG_X86_LOCAL_APIC
+	case FIX_APIC_BASE:	/* maps dummy local APIC */
+		pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
+		break;
+#endif
+
+#ifdef CONFIG_X86_IO_APIC
+	case FIX_IO_APIC_BASE_0 ... FIX_IO_APIC_BASE_END:
+		/*
+		 * We just don't map the IO APIC - all access is via
+		 * hypercalls.  Keep the address in the pte for reference.
+		 */
+		pte = pfn_pte(PFN_DOWN(__pa(fake_ioapic_mapping)), PAGE_KERNEL);
+		break;
+#endif
+
+	case FIX_PARAVIRT_BOOTMAP:
+		/* This is an MFN, but it isn't an IO mapping from the
+		   IO domain */
+		pte = mfn_pte(phys, prot);
+		break;
+
+	default:
+		/* By default, set_fixmap is used for hardware mappings */
+		pte = mfn_pte(phys, __pgprot(pgprot_val(prot) | _PAGE_IOMAP));
+		break;
+	}
+
+	__native_set_fixmap(idx, pte);
+
+#ifdef CONFIG_X86_64
+	/* Replicate changes to map the vsyscall page into the user
+	   pagetable vsyscall mapping. */
+	if ((idx >= VSYSCALL_LAST_PAGE && idx <= VSYSCALL_FIRST_PAGE) ||
+	    idx == VVAR_PAGE) {
+		unsigned long vaddr = __fix_to_virt(idx);
+		set_pte_vaddr_pud(level3_user_vsyscall, vaddr, pte);
+	}
+#endif
+}
+
+void __init xen_ident_map_ISA(void)
+{
+	unsigned long pa;
+
+	/*
+	 * If we're dom0, then linear map the ISA machine addresses into
+	 * the kernel's address space.
+	 */
+	if (!xen_initial_domain())
+		return;
+
+	xen_raw_printk("Xen: setup ISA identity maps\n");
+
+	for (pa = ISA_START_ADDRESS; pa < ISA_END_ADDRESS; pa += PAGE_SIZE) {
+		pte_t pte = mfn_pte(PFN_DOWN(pa), PAGE_KERNEL_IO);
+
+		if (HYPERVISOR_update_va_mapping(PAGE_OFFSET + pa, pte, 0))
+			BUG();
+	}
+
+	xen_flush_tlb();
+}
+
+static void __init xen_post_allocator_init(void)
+{
+	pv_mmu_ops.set_pte = xen_set_pte;
+	pv_mmu_ops.set_pmd = xen_set_pmd;
+	pv_mmu_ops.set_pud = xen_set_pud;
+#if PAGETABLE_LEVELS == 4
+	pv_mmu_ops.set_pgd = xen_set_pgd;
+#endif
+
+	/* This will work as long as patching hasn't happened yet
+	   (which it hasn't) */
+	pv_mmu_ops.alloc_pte = xen_alloc_pte;
+	pv_mmu_ops.alloc_pmd = xen_alloc_pmd;
+	pv_mmu_ops.release_pte = xen_release_pte;
+	pv_mmu_ops.release_pmd = xen_release_pmd;
+#if PAGETABLE_LEVELS == 4
+	pv_mmu_ops.alloc_pud = xen_alloc_pud;
+	pv_mmu_ops.release_pud = xen_release_pud;
+#endif
+
+#ifdef CONFIG_X86_64
+	SetPagePinned(virt_to_page(level3_user_vsyscall));
+#endif
+	xen_mark_init_mm_pinned();
+}
+
+static void xen_leave_lazy_mmu(void)
+{
+	preempt_disable();
+	xen_mc_flush();
+	paravirt_leave_lazy_mmu();
+	preempt_enable();
+}
+
+static const struct pv_mmu_ops xen_mmu_ops __initconst = {
+	.read_cr2 = xen_read_cr2,
+	.write_cr2 = xen_write_cr2,
+
+	.read_cr3 = xen_read_cr3,
+#ifdef CONFIG_X86_32
+	.write_cr3 = xen_write_cr3_init,
+#else
+	.write_cr3 = xen_write_cr3,
+#endif
+
+	.flush_tlb_user = xen_flush_tlb,
+	.flush_tlb_kernel = xen_flush_tlb,
+	.flush_tlb_single = xen_flush_tlb_single,
+	.flush_tlb_others = xen_flush_tlb_others,
+
+	.pte_update = paravirt_nop,
+	.pte_update_defer = paravirt_nop,
+
+	.pgd_alloc = xen_pgd_alloc,
+	.pgd_free = xen_pgd_free,
+
+	.alloc_pte = xen_alloc_pte_init,
+	.release_pte = xen_release_pte_init,
+	.alloc_pmd = xen_alloc_pmd_init,
+	.release_pmd = xen_release_pmd_init,
+
+	.set_pte = xen_set_pte_init,
+	.set_pte_at = xen_set_pte_at,
+	.set_pmd = xen_set_pmd_hyper,
+
+	.ptep_modify_prot_start = __ptep_modify_prot_start,
+	.ptep_modify_prot_commit = __ptep_modify_prot_commit,
+
+	.pte_val = PV_CALLEE_SAVE(xen_pte_val),
+	.pgd_val = PV_CALLEE_SAVE(xen_pgd_val),
+
+	.make_pte = PV_CALLEE_SAVE(xen_make_pte),
+	.make_pgd = PV_CALLEE_SAVE(xen_make_pgd),
+
+#ifdef CONFIG_X86_PAE
+	.set_pte_atomic = xen_set_pte_atomic,
+	.pte_clear = xen_pte_clear,
+	.pmd_clear = xen_pmd_clear,
+#endif	/* CONFIG_X86_PAE */
+	.set_pud = xen_set_pud_hyper,
+
+	.make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
+	.pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
+
+#if PAGETABLE_LEVELS == 4
+	.pud_val = PV_CALLEE_SAVE(xen_pud_val),
+	.make_pud = PV_CALLEE_SAVE(xen_make_pud),
+	.set_pgd = xen_set_pgd_hyper,
+
+	.alloc_pud = xen_alloc_pmd_init,
+	.release_pud = xen_release_pmd_init,
+#endif	/* PAGETABLE_LEVELS == 4 */
+
+	.activate_mm = xen_activate_mm,
+	.dup_mmap = xen_dup_mmap,
+	.exit_mmap = xen_exit_mmap,
+
+	.lazy_mode = {
+		.enter = paravirt_enter_lazy_mmu,
+		.leave = xen_leave_lazy_mmu,
+	},
+
+	.set_fixmap = xen_set_fixmap,
+};
+
+void __init xen_init_mmu_ops(void)
+{
+	x86_init.mapping.pagetable_reserve = xen_mapping_pagetable_reserve;
+	x86_init.paging.pagetable_setup_start = xen_pagetable_setup_start;
+	x86_init.paging.pagetable_setup_done = xen_pagetable_setup_done;
+	pv_mmu_ops = xen_mmu_ops;
+
+	memset(dummy_mapping, 0xff, PAGE_SIZE);
+	memset(fake_ioapic_mapping, 0xfd, PAGE_SIZE);
+}
+
+/* Protected by xen_reservation_lock. */
+#define MAX_CONTIG_ORDER 9 /* 2MB */
+static unsigned long discontig_frames[1<<MAX_CONTIG_ORDER];
+
+#define VOID_PTE (mfn_pte(0, __pgprot(0)))
+static void xen_zap_pfn_range(unsigned long vaddr, unsigned int order,
+				unsigned long *in_frames,
+				unsigned long *out_frames)
+{
+	int i;
+	struct multicall_space mcs;
+
+	xen_mc_batch();
+	for (i = 0; i < (1UL<<order); i++, vaddr += PAGE_SIZE) {
+		mcs = __xen_mc_entry(0);
+
+		if (in_frames)
+			in_frames[i] = virt_to_mfn(vaddr);
+
+		MULTI_update_va_mapping(mcs.mc, vaddr, VOID_PTE, 0);
+		__set_phys_to_machine(virt_to_pfn(vaddr), INVALID_P2M_ENTRY);
+
+		if (out_frames)
+			out_frames[i] = virt_to_pfn(vaddr);
+	}
+	xen_mc_issue(0);
+}
+
+/*
+ * Update the pfn-to-mfn mappings for a virtual address range, either to
+ * point to an array of mfns, or contiguously from a single starting
+ * mfn.
+ */
+static void xen_remap_exchanged_ptes(unsigned long vaddr, int order,
+				     unsigned long *mfns,
+				     unsigned long first_mfn)
+{
+	unsigned i, limit;
+	unsigned long mfn;
+
+	xen_mc_batch();
+
+	limit = 1u << order;
+	for (i = 0; i < limit; i++, vaddr += PAGE_SIZE) {
+		struct multicall_space mcs;
+		unsigned flags;
+
+		mcs = __xen_mc_entry(0);
+		if (mfns)
+			mfn = mfns[i];
+		else
+			mfn = first_mfn + i;
+
+		if (i < (limit - 1))
+			flags = 0;
+		else {
+			if (order == 0)
+				flags = UVMF_INVLPG | UVMF_ALL;
+			else
+				flags = UVMF_TLB_FLUSH | UVMF_ALL;
+		}
+
+		MULTI_update_va_mapping(mcs.mc, vaddr,
+				mfn_pte(mfn, PAGE_KERNEL), flags);
+
+		set_phys_to_machine(virt_to_pfn(vaddr), mfn);
+	}
+
+	xen_mc_issue(0);
+}
+
+/*
+ * Perform the hypercall to exchange a region of our pfns to point to
+ * memory with the required contiguous alignment.  Takes the pfns as
+ * input, and populates mfns as output.
+ *
+ * Returns a success code indicating whether the hypervisor was able to
+ * satisfy the request or not.
+ */
+static int xen_exchange_memory(unsigned long extents_in, unsigned int order_in,
+			       unsigned long *pfns_in,
+			       unsigned long extents_out,
+			       unsigned int order_out,
+			       unsigned long *mfns_out,
+			       unsigned int address_bits)
+{
+	long rc;
+	int success;
+
+	struct xen_memory_exchange exchange = {
+		.in = {
+			.nr_extents   = extents_in,
+			.extent_order = order_in,
+			.extent_start = pfns_in,
+			.domid        = DOMID_SELF
+		},
+		.out = {
+			.nr_extents   = extents_out,
+			.extent_order = order_out,
+			.extent_start = mfns_out,
+			.address_bits = address_bits,
+			.domid        = DOMID_SELF
+		}
+	};
+
+	BUG_ON(extents_in << order_in != extents_out << order_out);
+
+	rc = HYPERVISOR_memory_op(XENMEM_exchange, &exchange);
+	success = (exchange.nr_exchanged == extents_in);
+
+	BUG_ON(!success && ((exchange.nr_exchanged != 0) || (rc == 0)));
+	BUG_ON(success && (rc != 0));
+
+	return success;
+}
+
+int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
+				 unsigned int address_bits)
+{
+	unsigned long *in_frames = discontig_frames, out_frame;
+	unsigned long  flags;
+	int            success;
+
+	/*
+	 * Currently an auto-translated guest will not perform I/O, nor will
+	 * it require PAE page directories below 4GB. Therefore any calls to
+	 * this function are redundant and can be ignored.
+	 */
+
+	if (xen_feature(XENFEAT_auto_translated_physmap))
+		return 0;
+
+	if (unlikely(order > MAX_CONTIG_ORDER))
+		return -ENOMEM;
+
+	memset((void *) vstart, 0, PAGE_SIZE << order);
+
+	spin_lock_irqsave(&xen_reservation_lock, flags);
+
+	/* 1. Zap current PTEs, remembering MFNs. */
+	xen_zap_pfn_range(vstart, order, in_frames, NULL);
+
+	/* 2. Get a new contiguous memory extent. */
+	out_frame = virt_to_pfn(vstart);
+	success = xen_exchange_memory(1UL << order, 0, in_frames,
+				      1, order, &out_frame,
+				      address_bits);
+
+	/* 3. Map the new extent in place of old pages. */
+	if (success)
+		xen_remap_exchanged_ptes(vstart, order, NULL, out_frame);
+	else
+		xen_remap_exchanged_ptes(vstart, order, in_frames, 0);
+
+	spin_unlock_irqrestore(&xen_reservation_lock, flags);
+
+	return success ? 0 : -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
+
+void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)
+{
+	unsigned long *out_frames = discontig_frames, in_frame;
+	unsigned long  flags;
+	int success;
+
+	if (xen_feature(XENFEAT_auto_translated_physmap))
+		return;
+
+	if (unlikely(order > MAX_CONTIG_ORDER))
+		return;
+
+	memset((void *) vstart, 0, PAGE_SIZE << order);
+
+	spin_lock_irqsave(&xen_reservation_lock, flags);
+
+	/* 1. Find start MFN of contiguous extent. */
+	in_frame = virt_to_mfn(vstart);
+
+	/* 2. Zap current PTEs. */
+	xen_zap_pfn_range(vstart, order, NULL, out_frames);
+
+	/* 3. Do the exchange for non-contiguous MFNs. */
+	success = xen_exchange_memory(1, order, &in_frame, 1UL << order,
+					0, out_frames, 0);
+
+	/* 4. Map new pages in place of old pages. */
+	if (success)
+		xen_remap_exchanged_ptes(vstart, order, out_frames, 0);
+	else
+		xen_remap_exchanged_ptes(vstart, order, NULL, in_frame);
+
+	spin_unlock_irqrestore(&xen_reservation_lock, flags);
+}
+EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
+
+#ifdef CONFIG_XEN_PVHVM
+static void xen_hvm_exit_mmap(struct mm_struct *mm)
+{
+	struct xen_hvm_pagetable_dying a;
+	int rc;
+
+	a.domid = DOMID_SELF;
+	a.gpa = __pa(mm->pgd);
+	rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
+	WARN_ON_ONCE(rc < 0);
+}
+
+static int is_pagetable_dying_supported(void)
+{
+	struct xen_hvm_pagetable_dying a;
+	int rc = 0;
+
+	a.domid = DOMID_SELF;
+	a.gpa = 0x00;
+	rc = HYPERVISOR_hvm_op(HVMOP_pagetable_dying, &a);
+	if (rc < 0) {
+		printk(KERN_DEBUG "HVMOP_pagetable_dying not supported\n");
+		return 0;
+	}
+	return 1;
+}
+
+void __init xen_hvm_init_mmu_ops(void)
+{
+	if (is_pagetable_dying_supported())
+		pv_mmu_ops.exit_mmap = xen_hvm_exit_mmap;
+}
+#endif
+
+#define REMAP_BATCH_SIZE 16
+
+struct remap_data {
+	unsigned long mfn;
+	pgprot_t prot;
+	struct mmu_update *mmu_update;
+};
+
+static int remap_area_mfn_pte_fn(pte_t *ptep, pgtable_t token,
+				 unsigned long addr, void *data)
+{
+	struct remap_data *rmd = data;
+	pte_t pte = pte_mkspecial(pfn_pte(rmd->mfn++, rmd->prot));
+
+	rmd->mmu_update->ptr = virt_to_machine(ptep).maddr;
+	rmd->mmu_update->val = pte_val_ma(pte);
+	rmd->mmu_update++;
+
+	return 0;
+}
+
+int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
+			       unsigned long addr,
+			       unsigned long mfn, int nr,
+			       pgprot_t prot, unsigned domid)
+{
+	struct remap_data rmd;
+	struct mmu_update mmu_update[REMAP_BATCH_SIZE];
+	int batch;
+	unsigned long range;
+	int err = 0;
+
+	prot = __pgprot(pgprot_val(prot) | _PAGE_IOMAP);
+
+	BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_RESERVED | VM_IO)) ==
+				(VM_PFNMAP | VM_RESERVED | VM_IO)));
+
+	rmd.mfn = mfn;
+	rmd.prot = prot;
+
+	while (nr) {
+		batch = min(REMAP_BATCH_SIZE, nr);
+		range = (unsigned long)batch << PAGE_SHIFT;
+
+		rmd.mmu_update = mmu_update;
+		err = apply_to_page_range(vma->vm_mm, addr, range,
+					  remap_area_mfn_pte_fn, &rmd);
+		if (err)
+			goto out;
+
+		err = -EFAULT;
+		if (HYPERVISOR_mmu_update(mmu_update, batch, NULL, domid) < 0)
+			goto out;
+
+		nr -= batch;
+		addr += range;
+	}
+
+	err = 0;
+out:
+
+	flush_tlb_all();
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);
diff --git a/arch/x86/xen/mmu.h b/arch/x86/xen/mmu.h
new file mode 100644
index 00000000..73809bb9
--- /dev/null
+++ b/arch/x86/xen/mmu.h
@@ -0,0 +1,26 @@
+#ifndef _XEN_MMU_H
+
+#include <linux/linkage.h>
+#include <asm/page.h>
+
+enum pt_level {
+	PT_PGD,
+	PT_PUD,
+	PT_PMD,
+	PT_PTE
+};
+
+
+bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn);
+
+void set_pte_mfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags);
+
+pte_t xen_ptep_modify_prot_start(struct mm_struct *mm, unsigned long addr, pte_t *ptep);
+void  xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
+				  pte_t *ptep, pte_t pte);
+
+unsigned long xen_read_cr2_direct(void);
+
+extern void xen_init_mmu_ops(void);
+extern void xen_hvm_init_mmu_ops(void);
+#endif	/* _XEN_MMU_H */
diff --git a/arch/x86/xen/multicalls.c b/arch/x86/xen/multicalls.c
new file mode 100644
index 00000000..0d82003e
--- /dev/null
+++ b/arch/x86/xen/multicalls.c
@@ -0,0 +1,208 @@
+/*
+ * Xen hypercall batching.
+ *
+ * Xen allows multiple hypercalls to be issued at once, using the
+ * multicall interface.  This allows the cost of trapping into the
+ * hypervisor to be amortized over several calls.
+ *
+ * This file implements a simple interface for multicalls.  There's a
+ * per-cpu buffer of outstanding multicalls.  When you want to queue a
+ * multicall for issuing, you can allocate a multicall slot for the
+ * call and its arguments, along with storage for space which is
+ * pointed to by the arguments (for passing pointers to structures,
+ * etc).  When the multicall is actually issued, all the space for the
+ * commands and allocated memory is freed for reuse.
+ *
+ * Multicalls are flushed whenever any of the buffers get full, or
+ * when explicitly requested.  There's no way to get per-multicall
+ * return results back.  It will BUG if any of the multicalls fail.
+ *
+ * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
+ */
+#include <linux/percpu.h>
+#include <linux/hardirq.h>
+#include <linux/debugfs.h>
+
+#include <asm/xen/hypercall.h>
+
+#include "multicalls.h"
+#include "debugfs.h"
+
+#define MC_BATCH	32
+
+#define MC_DEBUG	0
+
+#define MC_ARGS		(MC_BATCH * 16)
+
+
+struct mc_buffer {
+	unsigned mcidx, argidx, cbidx;
+	struct multicall_entry entries[MC_BATCH];
+#if MC_DEBUG
+	struct multicall_entry debug[MC_BATCH];
+	void *caller[MC_BATCH];
+#endif
+	unsigned char args[MC_ARGS];
+	struct callback {
+		void (*fn)(void *);
+		void *data;
+	} callbacks[MC_BATCH];
+};
+
+static DEFINE_PER_CPU(struct mc_buffer, mc_buffer);
+DEFINE_PER_CPU(unsigned long, xen_mc_irq_flags);
+
+void xen_mc_flush(void)
+{
+	struct mc_buffer *b = &__get_cpu_var(mc_buffer);
+	struct multicall_entry *mc;
+	int ret = 0;
+	unsigned long flags;
+	int i;
+
+	BUG_ON(preemptible());
+
+	/* Disable interrupts in case someone comes in and queues
+	   something in the middle */
+	local_irq_save(flags);
+
+	trace_xen_mc_flush(b->mcidx, b->argidx, b->cbidx);
+
+	switch (b->mcidx) {
+	case 0:
+		/* no-op */
+		BUG_ON(b->argidx != 0);
+		break;
+
+	case 1:
+		/* Singleton multicall - bypass multicall machinery
+		   and just do the call directly. */
+		mc = &b->entries[0];
+
+		mc->result = privcmd_call(mc->op,
+					  mc->args[0], mc->args[1], mc->args[2], 
+					  mc->args[3], mc->args[4]);
+		ret = mc->result < 0;
+		break;
+
+	default:
+#if MC_DEBUG
+		memcpy(b->debug, b->entries,
+		       b->mcidx * sizeof(struct multicall_entry));
+#endif
+
+		if (HYPERVISOR_multicall(b->entries, b->mcidx) != 0)
+			BUG();
+		for (i = 0; i < b->mcidx; i++)
+			if (b->entries[i].result < 0)
+				ret++;
+
+#if MC_DEBUG
+		if (ret) {
+			printk(KERN_ERR "%d multicall(s) failed: cpu %d\n",
+			       ret, smp_processor_id());
+			dump_stack();
+			for (i = 0; i < b->mcidx; i++) {
+				printk(KERN_DEBUG "  call %2d/%d: op=%lu arg=[%lx] result=%ld\t%pF\n",
+				       i+1, b->mcidx,
+				       b->debug[i].op,
+				       b->debug[i].args[0],
+				       b->entries[i].result,
+				       b->caller[i]);
+			}
+		}
+#endif
+	}
+
+	b->mcidx = 0;
+	b->argidx = 0;
+
+	for (i = 0; i < b->cbidx; i++) {
+		struct callback *cb = &b->callbacks[i];
+
+		(*cb->fn)(cb->data);
+	}
+	b->cbidx = 0;
+
+	local_irq_restore(flags);
+
+	WARN_ON(ret);
+}
+
+struct multicall_space __xen_mc_entry(size_t args)
+{
+	struct mc_buffer *b = &__get_cpu_var(mc_buffer);
+	struct multicall_space ret;
+	unsigned argidx = roundup(b->argidx, sizeof(u64));
+
+	trace_xen_mc_entry_alloc(args);
+
+	BUG_ON(preemptible());
+	BUG_ON(b->argidx >= MC_ARGS);
+
+	if (unlikely(b->mcidx == MC_BATCH ||
+		     (argidx + args) >= MC_ARGS)) {
+		trace_xen_mc_flush_reason((b->mcidx == MC_BATCH) ?
+					  XEN_MC_FL_BATCH : XEN_MC_FL_ARGS);
+		xen_mc_flush();
+		argidx = roundup(b->argidx, sizeof(u64));
+	}
+
+	ret.mc = &b->entries[b->mcidx];
+#if MC_DEBUG
+	b->caller[b->mcidx] = __builtin_return_address(0);
+#endif
+	b->mcidx++;
+	ret.args = &b->args[argidx];
+	b->argidx = argidx + args;
+
+	BUG_ON(b->argidx >= MC_ARGS);
+	return ret;
+}
+
+struct multicall_space xen_mc_extend_args(unsigned long op, size_t size)
+{
+	struct mc_buffer *b = &__get_cpu_var(mc_buffer);
+	struct multicall_space ret = { NULL, NULL };
+
+	BUG_ON(preemptible());
+	BUG_ON(b->argidx >= MC_ARGS);
+
+	if (unlikely(b->mcidx == 0 ||
+		     b->entries[b->mcidx - 1].op != op)) {
+		trace_xen_mc_extend_args(op, size, XEN_MC_XE_BAD_OP);
+		goto out;
+	}
+
+	if (unlikely((b->argidx + size) >= MC_ARGS)) {
+		trace_xen_mc_extend_args(op, size, XEN_MC_XE_NO_SPACE);
+		goto out;
+	}
+
+	ret.mc = &b->entries[b->mcidx - 1];
+	ret.args = &b->args[b->argidx];
+	b->argidx += size;
+
+	BUG_ON(b->argidx >= MC_ARGS);
+
+	trace_xen_mc_extend_args(op, size, XEN_MC_XE_OK);
+out:
+	return ret;
+}
+
+void xen_mc_callback(void (*fn)(void *), void *data)
+{
+	struct mc_buffer *b = &__get_cpu_var(mc_buffer);
+	struct callback *cb;
+
+	if (b->cbidx == MC_BATCH) {
+		trace_xen_mc_flush_reason(XEN_MC_FL_CALLBACK);
+		xen_mc_flush();
+	}
+
+	trace_xen_mc_callback(fn, data);
+
+	cb = &b->callbacks[b->cbidx++];
+	cb->fn = fn;
+	cb->data = data;
+}
diff --git a/arch/x86/xen/multicalls.h b/arch/x86/xen/multicalls.h
new file mode 100644
index 00000000..9c2e74f9
--- /dev/null
+++ b/arch/x86/xen/multicalls.h
@@ -0,0 +1,68 @@
+#ifndef _XEN_MULTICALLS_H
+#define _XEN_MULTICALLS_H
+
+#include <trace/events/xen.h>
+
+#include "xen-ops.h"
+
+/* Multicalls */
+struct multicall_space
+{
+	struct multicall_entry *mc;
+	void *args;
+};
+
+/* Allocate room for a multicall and its args */
+struct multicall_space __xen_mc_entry(size_t args);
+
+DECLARE_PER_CPU(unsigned long, xen_mc_irq_flags);
+
+/* Call to start a batch of multiple __xen_mc_entry()s.  Must be
+   paired with xen_mc_issue() */
+static inline void xen_mc_batch(void)
+{
+	unsigned long flags;
+
+	/* need to disable interrupts until this entry is complete */
+	local_irq_save(flags);
+	trace_xen_mc_batch(paravirt_get_lazy_mode());
+	__this_cpu_write(xen_mc_irq_flags, flags);
+}
+
+static inline struct multicall_space xen_mc_entry(size_t args)
+{
+	xen_mc_batch();
+	return __xen_mc_entry(args);
+}
+
+/* Flush all pending multicalls */
+void xen_mc_flush(void);
+
+/* Issue a multicall if we're not in a lazy mode */
+static inline void xen_mc_issue(unsigned mode)
+{
+	trace_xen_mc_issue(mode);
+
+	if ((paravirt_get_lazy_mode() & mode) == 0)
+		xen_mc_flush();
+
+	/* restore flags saved in xen_mc_batch */
+	local_irq_restore(this_cpu_read(xen_mc_irq_flags));
+}
+
+/* Set up a callback to be called when the current batch is flushed */
+void xen_mc_callback(void (*fn)(void *), void *data);
+
+/*
+ * Try to extend the arguments of the previous multicall command.  The
+ * previous command's op must match.  If it does, then it attempts to
+ * extend the argument space allocated to the multicall entry by
+ * arg_size bytes.
+ *
+ * The returned multicall_space will return with mc pointing to the
+ * command on success, or NULL on failure, and args pointing to the
+ * newly allocated space.
+ */
+struct multicall_space xen_mc_extend_args(unsigned long op, size_t arg_size);
+
+#endif /* _XEN_MULTICALLS_H */
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
new file mode 100644
index 00000000..1b267e75
--- /dev/null
+++ b/arch/x86/xen/p2m.c
@@ -0,0 +1,949 @@
+/*
+ * Xen leaves the responsibility for maintaining p2m mappings to the
+ * guests themselves, but it must also access and update the p2m array
+ * during suspend/resume when all the pages are reallocated.
+ *
+ * The p2m table is logically a flat array, but we implement it as a
+ * three-level tree to allow the address space to be sparse.
+ *
+ *                               Xen
+ *                                |
+ *     p2m_top              p2m_top_mfn
+ *       /  \                   /   \
+ * p2m_mid p2m_mid	p2m_mid_mfn p2m_mid_mfn
+ *    / \      / \         /           /
+ *  p2m p2m p2m p2m p2m p2m p2m ...
+ *
+ * The p2m_mid_mfn pages are mapped by p2m_top_mfn_p.
+ *
+ * The p2m_top and p2m_top_mfn levels are limited to 1 page, so the
+ * maximum representable pseudo-physical address space is:
+ *  P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE pages
+ *
+ * P2M_PER_PAGE depends on the architecture, as a mfn is always
+ * unsigned long (8 bytes on 64-bit, 4 bytes on 32), leading to
+ * 512 and 1024 entries respectively. 
+ *
+ * In short, these structures contain the Machine Frame Number (MFN) of the PFN.
+ *
+ * However not all entries are filled with MFNs. Specifically for all other
+ * leaf entries, or for the top  root, or middle one, for which there is a void
+ * entry, we assume it is  "missing". So (for example)
+ *  pfn_to_mfn(0x90909090)=INVALID_P2M_ENTRY.
+ *
+ * We also have the possibility of setting 1-1 mappings on certain regions, so
+ * that:
+ *  pfn_to_mfn(0xc0000)=0xc0000
+ *
+ * The benefit of this is, that we can assume for non-RAM regions (think
+ * PCI BARs, or ACPI spaces), we can create mappings easily b/c we
+ * get the PFN value to match the MFN.
+ *
+ * For this to work efficiently we have one new page p2m_identity and
+ * allocate (via reserved_brk) any other pages we need to cover the sides
+ * (1GB or 4MB boundary violations). All entries in p2m_identity are set to
+ * INVALID_P2M_ENTRY type (Xen toolstack only recognizes that and MFNs,
+ * no other fancy value).
+ *
+ * On lookup we spot that the entry points to p2m_identity and return the
+ * identity value instead of dereferencing and returning INVALID_P2M_ENTRY.
+ * If the entry points to an allocated page, we just proceed as before and
+ * return the PFN.  If the PFN has IDENTITY_FRAME_BIT set we unmask that in
+ * appropriate functions (pfn_to_mfn).
+ *
+ * The reason for having the IDENTITY_FRAME_BIT instead of just returning the
+ * PFN is that we could find ourselves where pfn_to_mfn(pfn)==pfn for a
+ * non-identity pfn. To protect ourselves against we elect to set (and get) the
+ * IDENTITY_FRAME_BIT on all identity mapped PFNs.
+ *
+ * This simplistic diagram is used to explain the more subtle piece of code.
+ * There is also a digram of the P2M at the end that can help.
+ * Imagine your E820 looking as so:
+ *
+ *                    1GB                                           2GB
+ * /-------------------+---------\/----\         /----------\    /---+-----\
+ * | System RAM        | Sys RAM ||ACPI|         | reserved |    | Sys RAM |
+ * \-------------------+---------/\----/         \----------/    \---+-----/
+ *                               ^- 1029MB                       ^- 2001MB
+ *
+ * [1029MB = 263424 (0x40500), 2001MB = 512256 (0x7D100),
+ *  2048MB = 524288 (0x80000)]
+ *
+ * And dom0_mem=max:3GB,1GB is passed in to the guest, meaning memory past 1GB
+ * is actually not present (would have to kick the balloon driver to put it in).
+ *
+ * When we are told to set the PFNs for identity mapping (see patch: "xen/setup:
+ * Set identity mapping for non-RAM E820 and E820 gaps.") we pass in the start
+ * of the PFN and the end PFN (263424 and 512256 respectively). The first step
+ * is to reserve_brk a top leaf page if the p2m[1] is missing. The top leaf page
+ * covers 512^2 of page estate (1GB) and in case the start or end PFN is not
+ * aligned on 512^2*PAGE_SIZE (1GB) we loop on aligned 1GB PFNs from start pfn
+ * to end pfn.  We reserve_brk top leaf pages if they are missing (means they
+ * point to p2m_mid_missing).
+ *
+ * With the E820 example above, 263424 is not 1GB aligned so we allocate a
+ * reserve_brk page which will cover the PFNs estate from 0x40000 to 0x80000.
+ * Each entry in the allocate page is "missing" (points to p2m_missing).
+ *
+ * Next stage is to determine if we need to do a more granular boundary check
+ * on the 4MB (or 2MB depending on architecture) off the start and end pfn's.
+ * We check if the start pfn and end pfn violate that boundary check, and if
+ * so reserve_brk a middle (p2m[x][y]) leaf page. This way we have a much finer
+ * granularity of setting which PFNs are missing and which ones are identity.
+ * In our example 263424 and 512256 both fail the check so we reserve_brk two
+ * pages. Populate them with INVALID_P2M_ENTRY (so they both have "missing"
+ * values) and assign them to p2m[1][2] and p2m[1][488] respectively.
+ *
+ * At this point we would at minimum reserve_brk one page, but could be up to
+ * three. Each call to set_phys_range_identity has at maximum a three page
+ * cost. If we were to query the P2M at this stage, all those entries from
+ * start PFN through end PFN (so 1029MB -> 2001MB) would return
+ * INVALID_P2M_ENTRY ("missing").
+ *
+ * The next step is to walk from the start pfn to the end pfn setting
+ * the IDENTITY_FRAME_BIT on each PFN. This is done in set_phys_range_identity.
+ * If we find that the middle leaf is pointing to p2m_missing we can swap it
+ * over to p2m_identity - this way covering 4MB (or 2MB) PFN space.  At this
+ * point we do not need to worry about boundary aligment (so no need to
+ * reserve_brk a middle page, figure out which PFNs are "missing" and which
+ * ones are identity), as that has been done earlier.  If we find that the
+ * middle leaf is not occupied by p2m_identity or p2m_missing, we dereference
+ * that page (which covers 512 PFNs) and set the appropriate PFN with
+ * IDENTITY_FRAME_BIT. In our example 263424 and 512256 end up there, and we
+ * set from p2m[1][2][256->511] and p2m[1][488][0->256] with
+ * IDENTITY_FRAME_BIT set.
+ *
+ * All other regions that are void (or not filled) either point to p2m_missing
+ * (considered missing) or have the default value of INVALID_P2M_ENTRY (also
+ * considered missing). In our case, p2m[1][2][0->255] and p2m[1][488][257->511]
+ * contain the INVALID_P2M_ENTRY value and are considered "missing."
+ *
+ * This is what the p2m ends up looking (for the E820 above) with this
+ * fabulous drawing:
+ *
+ *    p2m         /--------------\
+ *  /-----\       | &mfn_list[0],|                           /-----------------\
+ *  |  0  |------>| &mfn_list[1],|    /---------------\      | ~0, ~0, ..      |
+ *  |-----|       |  ..., ~0, ~0 |    | ~0, ~0, [x]---+----->| IDENTITY [@256] |
+ *  |  1  |---\   \--------------/    | [p2m_identity]+\     | IDENTITY [@257] |
+ *  |-----|    \                      | [p2m_identity]+\\    | ....            |
+ *  |  2  |--\  \-------------------->|  ...          | \\   \----------------/
+ *  |-----|   \                       \---------------/  \\
+ *  |  3  |\   \                                          \\  p2m_identity
+ *  |-----| \   \-------------------->/---------------\   /-----------------\
+ *  | ..  +->+                        | [p2m_identity]+-->| ~0, ~0, ~0, ... |
+ *  \-----/ /                         | [p2m_identity]+-->| ..., ~0         |
+ *         / /---------------\        | ....          |   \-----------------/
+ *        /  | IDENTITY[@0]  |      /-+-[x], ~0, ~0.. |
+ *       /   | IDENTITY[@256]|<----/  \---------------/
+ *      /    | ~0, ~0, ....  |
+ *     |     \---------------/
+ *     |
+ *     p2m_missing             p2m_missing
+ * /------------------\     /------------\
+ * | [p2m_mid_missing]+---->| ~0, ~0, ~0 |
+ * | [p2m_mid_missing]+---->| ..., ~0    |
+ * \------------------/     \------------/
+ *
+ * where ~0 is INVALID_P2M_ENTRY. IDENTITY is (PFN | IDENTITY_BIT)
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/hash.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+
+#include <asm/cache.h>
+#include <asm/setup.h>
+
+#include <asm/xen/page.h>
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+#include <xen/grant_table.h>
+
+#include "multicalls.h"
+#include "xen-ops.h"
+
+static void __init m2p_override_init(void);
+
+unsigned long xen_max_p2m_pfn __read_mostly;
+
+#define P2M_PER_PAGE		(PAGE_SIZE / sizeof(unsigned long))
+#define P2M_MID_PER_PAGE	(PAGE_SIZE / sizeof(unsigned long *))
+#define P2M_TOP_PER_PAGE	(PAGE_SIZE / sizeof(unsigned long **))
+
+#define MAX_P2M_PFN		(P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE)
+
+/* Placeholders for holes in the address space */
+static RESERVE_BRK_ARRAY(unsigned long, p2m_missing, P2M_PER_PAGE);
+static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_missing, P2M_MID_PER_PAGE);
+static RESERVE_BRK_ARRAY(unsigned long, p2m_mid_missing_mfn, P2M_MID_PER_PAGE);
+
+static RESERVE_BRK_ARRAY(unsigned long **, p2m_top, P2M_TOP_PER_PAGE);
+static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn, P2M_TOP_PER_PAGE);
+static RESERVE_BRK_ARRAY(unsigned long *, p2m_top_mfn_p, P2M_TOP_PER_PAGE);
+
+static RESERVE_BRK_ARRAY(unsigned long, p2m_identity, P2M_PER_PAGE);
+
+RESERVE_BRK(p2m_mid, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));
+RESERVE_BRK(p2m_mid_mfn, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));
+
+/* We might hit two boundary violations at the start and end, at max each
+ * boundary violation will require three middle nodes. */
+RESERVE_BRK(p2m_mid_identity, PAGE_SIZE * 2 * 3);
+
+static inline unsigned p2m_top_index(unsigned long pfn)
+{
+	BUG_ON(pfn >= MAX_P2M_PFN);
+	return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE);
+}
+
+static inline unsigned p2m_mid_index(unsigned long pfn)
+{
+	return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE;
+}
+
+static inline unsigned p2m_index(unsigned long pfn)
+{
+	return pfn % P2M_PER_PAGE;
+}
+
+static void p2m_top_init(unsigned long ***top)
+{
+	unsigned i;
+
+	for (i = 0; i < P2M_TOP_PER_PAGE; i++)
+		top[i] = p2m_mid_missing;
+}
+
+static void p2m_top_mfn_init(unsigned long *top)
+{
+	unsigned i;
+
+	for (i = 0; i < P2M_TOP_PER_PAGE; i++)
+		top[i] = virt_to_mfn(p2m_mid_missing_mfn);
+}
+
+static void p2m_top_mfn_p_init(unsigned long **top)
+{
+	unsigned i;
+
+	for (i = 0; i < P2M_TOP_PER_PAGE; i++)
+		top[i] = p2m_mid_missing_mfn;
+}
+
+static void p2m_mid_init(unsigned long **mid)
+{
+	unsigned i;
+
+	for (i = 0; i < P2M_MID_PER_PAGE; i++)
+		mid[i] = p2m_missing;
+}
+
+static void p2m_mid_mfn_init(unsigned long *mid)
+{
+	unsigned i;
+
+	for (i = 0; i < P2M_MID_PER_PAGE; i++)
+		mid[i] = virt_to_mfn(p2m_missing);
+}
+
+static void p2m_init(unsigned long *p2m)
+{
+	unsigned i;
+
+	for (i = 0; i < P2M_MID_PER_PAGE; i++)
+		p2m[i] = INVALID_P2M_ENTRY;
+}
+
+/*
+ * Build the parallel p2m_top_mfn and p2m_mid_mfn structures
+ *
+ * This is called both at boot time, and after resuming from suspend:
+ * - At boot time we're called very early, and must use extend_brk()
+ *   to allocate memory.
+ *
+ * - After resume we're called from within stop_machine, but the mfn
+ *   tree should alreay be completely allocated.
+ */
+void __ref xen_build_mfn_list_list(void)
+{
+	unsigned long pfn;
+
+	/* Pre-initialize p2m_top_mfn to be completely missing */
+	if (p2m_top_mfn == NULL) {
+		p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE);
+		p2m_mid_mfn_init(p2m_mid_missing_mfn);
+
+		p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);
+		p2m_top_mfn_p_init(p2m_top_mfn_p);
+
+		p2m_top_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE);
+		p2m_top_mfn_init(p2m_top_mfn);
+	} else {
+		/* Reinitialise, mfn's all change after migration */
+		p2m_mid_mfn_init(p2m_mid_missing_mfn);
+	}
+
+	for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += P2M_PER_PAGE) {
+		unsigned topidx = p2m_top_index(pfn);
+		unsigned mididx = p2m_mid_index(pfn);
+		unsigned long **mid;
+		unsigned long *mid_mfn_p;
+
+		mid = p2m_top[topidx];
+		mid_mfn_p = p2m_top_mfn_p[topidx];
+
+		/* Don't bother allocating any mfn mid levels if
+		 * they're just missing, just update the stored mfn,
+		 * since all could have changed over a migrate.
+		 */
+		if (mid == p2m_mid_missing) {
+			BUG_ON(mididx);
+			BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
+			p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn);
+			pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE;
+			continue;
+		}
+
+		if (mid_mfn_p == p2m_mid_missing_mfn) {
+			/*
+			 * XXX boot-time only!  We should never find
+			 * missing parts of the mfn tree after
+			 * runtime.  extend_brk() will BUG if we call
+			 * it too late.
+			 */
+			mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);
+			p2m_mid_mfn_init(mid_mfn_p);
+
+			p2m_top_mfn_p[topidx] = mid_mfn_p;
+		}
+
+		p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
+		mid_mfn_p[mididx] = virt_to_mfn(mid[mididx]);
+	}
+}
+
+void xen_setup_mfn_list_list(void)
+{
+	BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
+
+	HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
+		virt_to_mfn(p2m_top_mfn);
+	HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn;
+}
+
+/* Set up p2m_top to point to the domain-builder provided p2m pages */
+void __init xen_build_dynamic_phys_to_machine(void)
+{
+	unsigned long *mfn_list = (unsigned long *)xen_start_info->mfn_list;
+	unsigned long max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages);
+	unsigned long pfn;
+
+	xen_max_p2m_pfn = max_pfn;
+
+	p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE);
+	p2m_init(p2m_missing);
+
+	p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE);
+	p2m_mid_init(p2m_mid_missing);
+
+	p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE);
+	p2m_top_init(p2m_top);
+
+	p2m_identity = extend_brk(PAGE_SIZE, PAGE_SIZE);
+	p2m_init(p2m_identity);
+
+	/*
+	 * The domain builder gives us a pre-constructed p2m array in
+	 * mfn_list for all the pages initially given to us, so we just
+	 * need to graft that into our tree structure.
+	 */
+	for (pfn = 0; pfn < max_pfn; pfn += P2M_PER_PAGE) {
+		unsigned topidx = p2m_top_index(pfn);
+		unsigned mididx = p2m_mid_index(pfn);
+
+		if (p2m_top[topidx] == p2m_mid_missing) {
+			unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE);
+			p2m_mid_init(mid);
+
+			p2m_top[topidx] = mid;
+		}
+
+		/*
+		 * As long as the mfn_list has enough entries to completely
+		 * fill a p2m page, pointing into the array is ok. But if
+		 * not the entries beyond the last pfn will be undefined.
+		 */
+		if (unlikely(pfn + P2M_PER_PAGE > max_pfn)) {
+			unsigned long p2midx;
+
+			p2midx = max_pfn % P2M_PER_PAGE;
+			for ( ; p2midx < P2M_PER_PAGE; p2midx++)
+				mfn_list[pfn + p2midx] = INVALID_P2M_ENTRY;
+		}
+		p2m_top[topidx][mididx] = &mfn_list[pfn];
+	}
+
+	m2p_override_init();
+}
+
+unsigned long get_phys_to_machine(unsigned long pfn)
+{
+	unsigned topidx, mididx, idx;
+
+	if (unlikely(pfn >= MAX_P2M_PFN))
+		return INVALID_P2M_ENTRY;
+
+	topidx = p2m_top_index(pfn);
+	mididx = p2m_mid_index(pfn);
+	idx = p2m_index(pfn);
+
+	/*
+	 * The INVALID_P2M_ENTRY is filled in both p2m_*identity
+	 * and in p2m_*missing, so returning the INVALID_P2M_ENTRY
+	 * would be wrong.
+	 */
+	if (p2m_top[topidx][mididx] == p2m_identity)
+		return IDENTITY_FRAME(pfn);
+
+	return p2m_top[topidx][mididx][idx];
+}
+EXPORT_SYMBOL_GPL(get_phys_to_machine);
+
+static void *alloc_p2m_page(void)
+{
+	return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT);
+}
+
+static void free_p2m_page(void *p)
+{
+	free_page((unsigned long)p);
+}
+
+/* 
+ * Fully allocate the p2m structure for a given pfn.  We need to check
+ * that both the top and mid levels are allocated, and make sure the
+ * parallel mfn tree is kept in sync.  We may race with other cpus, so
+ * the new pages are installed with cmpxchg; if we lose the race then
+ * simply free the page we allocated and use the one that's there.
+ */
+static bool alloc_p2m(unsigned long pfn)
+{
+	unsigned topidx, mididx;
+	unsigned long ***top_p, **mid;
+	unsigned long *top_mfn_p, *mid_mfn;
+
+	topidx = p2m_top_index(pfn);
+	mididx = p2m_mid_index(pfn);
+
+	top_p = &p2m_top[topidx];
+	mid = *top_p;
+
+	if (mid == p2m_mid_missing) {
+		/* Mid level is missing, allocate a new one */
+		mid = alloc_p2m_page();
+		if (!mid)
+			return false;
+
+		p2m_mid_init(mid);
+
+		if (cmpxchg(top_p, p2m_mid_missing, mid) != p2m_mid_missing)
+			free_p2m_page(mid);
+	}
+
+	top_mfn_p = &p2m_top_mfn[topidx];
+	mid_mfn = p2m_top_mfn_p[topidx];
+
+	BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p);
+
+	if (mid_mfn == p2m_mid_missing_mfn) {
+		/* Separately check the mid mfn level */
+		unsigned long missing_mfn;
+		unsigned long mid_mfn_mfn;
+
+		mid_mfn = alloc_p2m_page();
+		if (!mid_mfn)
+			return false;
+
+		p2m_mid_mfn_init(mid_mfn);
+
+		missing_mfn = virt_to_mfn(p2m_mid_missing_mfn);
+		mid_mfn_mfn = virt_to_mfn(mid_mfn);
+		if (cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn) != missing_mfn)
+			free_p2m_page(mid_mfn);
+		else
+			p2m_top_mfn_p[topidx] = mid_mfn;
+	}
+
+	if (p2m_top[topidx][mididx] == p2m_identity ||
+	    p2m_top[topidx][mididx] == p2m_missing) {
+		/* p2m leaf page is missing */
+		unsigned long *p2m;
+		unsigned long *p2m_orig = p2m_top[topidx][mididx];
+
+		p2m = alloc_p2m_page();
+		if (!p2m)
+			return false;
+
+		p2m_init(p2m);
+
+		if (cmpxchg(&mid[mididx], p2m_orig, p2m) != p2m_orig)
+			free_p2m_page(p2m);
+		else
+			mid_mfn[mididx] = virt_to_mfn(p2m);
+	}
+
+	return true;
+}
+
+static bool __init __early_alloc_p2m(unsigned long pfn)
+{
+	unsigned topidx, mididx, idx;
+
+	topidx = p2m_top_index(pfn);
+	mididx = p2m_mid_index(pfn);
+	idx = p2m_index(pfn);
+
+	/* Pfff.. No boundary cross-over, lets get out. */
+	if (!idx)
+		return false;
+
+	WARN(p2m_top[topidx][mididx] == p2m_identity,
+		"P2M[%d][%d] == IDENTITY, should be MISSING (or alloced)!\n",
+		topidx, mididx);
+
+	/*
+	 * Could be done by xen_build_dynamic_phys_to_machine..
+	 */
+	if (p2m_top[topidx][mididx] != p2m_missing)
+		return false;
+
+	/* Boundary cross-over for the edges: */
+	if (idx) {
+		unsigned long *p2m = extend_brk(PAGE_SIZE, PAGE_SIZE);
+		unsigned long *mid_mfn_p;
+
+		p2m_init(p2m);
+
+		p2m_top[topidx][mididx] = p2m;
+
+		/* For save/restore we need to MFN of the P2M saved */
+		
+		mid_mfn_p = p2m_top_mfn_p[topidx];
+		WARN(mid_mfn_p[mididx] != virt_to_mfn(p2m_missing),
+			"P2M_TOP_P[%d][%d] != MFN of p2m_missing!\n",
+			topidx, mididx);
+		mid_mfn_p[mididx] = virt_to_mfn(p2m);
+
+	}
+	return idx != 0;
+}
+unsigned long __init set_phys_range_identity(unsigned long pfn_s,
+				      unsigned long pfn_e)
+{
+	unsigned long pfn;
+
+	if (unlikely(pfn_s >= MAX_P2M_PFN || pfn_e >= MAX_P2M_PFN))
+		return 0;
+
+	if (unlikely(xen_feature(XENFEAT_auto_translated_physmap)))
+		return pfn_e - pfn_s;
+
+	if (pfn_s > pfn_e)
+		return 0;
+
+	for (pfn = (pfn_s & ~(P2M_MID_PER_PAGE * P2M_PER_PAGE - 1));
+		pfn < ALIGN(pfn_e, (P2M_MID_PER_PAGE * P2M_PER_PAGE));
+		pfn += P2M_MID_PER_PAGE * P2M_PER_PAGE)
+	{
+		unsigned topidx = p2m_top_index(pfn);
+		unsigned long *mid_mfn_p;
+		unsigned long **mid;
+
+		mid = p2m_top[topidx];
+		mid_mfn_p = p2m_top_mfn_p[topidx];
+		if (mid == p2m_mid_missing) {
+			mid = extend_brk(PAGE_SIZE, PAGE_SIZE);
+
+			p2m_mid_init(mid);
+
+			p2m_top[topidx] = mid;
+
+			BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
+		}
+		/* And the save/restore P2M tables.. */
+		if (mid_mfn_p == p2m_mid_missing_mfn) {
+			mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);
+			p2m_mid_mfn_init(mid_mfn_p);
+
+			p2m_top_mfn_p[topidx] = mid_mfn_p;
+			p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
+			/* Note: we don't set mid_mfn_p[midix] here,
+		 	 * look in __early_alloc_p2m */
+		}
+	}
+
+	__early_alloc_p2m(pfn_s);
+	__early_alloc_p2m(pfn_e);
+
+	for (pfn = pfn_s; pfn < pfn_e; pfn++)
+		if (!__set_phys_to_machine(pfn, IDENTITY_FRAME(pfn)))
+			break;
+
+	if (!WARN((pfn - pfn_s) != (pfn_e - pfn_s),
+		"Identity mapping failed. We are %ld short of 1-1 mappings!\n",
+		(pfn_e - pfn_s) - (pfn - pfn_s)))
+		printk(KERN_DEBUG "1-1 mapping on %lx->%lx\n", pfn_s, pfn);
+
+	return pfn - pfn_s;
+}
+
+/* Try to install p2m mapping; fail if intermediate bits missing */
+bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
+{
+	unsigned topidx, mididx, idx;
+
+	if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {
+		BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
+		return true;
+	}
+	if (unlikely(pfn >= MAX_P2M_PFN)) {
+		BUG_ON(mfn != INVALID_P2M_ENTRY);
+		return true;
+	}
+
+	topidx = p2m_top_index(pfn);
+	mididx = p2m_mid_index(pfn);
+	idx = p2m_index(pfn);
+
+	/* For sparse holes were the p2m leaf has real PFN along with
+	 * PCI holes, stick in the PFN as the MFN value.
+	 */
+	if (mfn != INVALID_P2M_ENTRY && (mfn & IDENTITY_FRAME_BIT)) {
+		if (p2m_top[topidx][mididx] == p2m_identity)
+			return true;
+
+		/* Swap over from MISSING to IDENTITY if needed. */
+		if (p2m_top[topidx][mididx] == p2m_missing) {
+			WARN_ON(cmpxchg(&p2m_top[topidx][mididx], p2m_missing,
+				p2m_identity) != p2m_missing);
+			return true;
+		}
+	}
+
+	if (p2m_top[topidx][mididx] == p2m_missing)
+		return mfn == INVALID_P2M_ENTRY;
+
+	p2m_top[topidx][mididx][idx] = mfn;
+
+	return true;
+}
+
+bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
+{
+	if (unlikely(!__set_phys_to_machine(pfn, mfn)))  {
+		if (!alloc_p2m(pfn))
+			return false;
+
+		if (!__set_phys_to_machine(pfn, mfn))
+			return false;
+	}
+
+	return true;
+}
+
+#define M2P_OVERRIDE_HASH_SHIFT	10
+#define M2P_OVERRIDE_HASH	(1 << M2P_OVERRIDE_HASH_SHIFT)
+
+static RESERVE_BRK_ARRAY(struct list_head, m2p_overrides, M2P_OVERRIDE_HASH);
+static DEFINE_SPINLOCK(m2p_override_lock);
+
+static void __init m2p_override_init(void)
+{
+	unsigned i;
+
+	m2p_overrides = extend_brk(sizeof(*m2p_overrides) * M2P_OVERRIDE_HASH,
+				   sizeof(unsigned long));
+
+	for (i = 0; i < M2P_OVERRIDE_HASH; i++)
+		INIT_LIST_HEAD(&m2p_overrides[i]);
+}
+
+static unsigned long mfn_hash(unsigned long mfn)
+{
+	return hash_long(mfn, M2P_OVERRIDE_HASH_SHIFT);
+}
+
+/* Add an MFN override for a particular page */
+int m2p_add_override(unsigned long mfn, struct page *page,
+		struct gnttab_map_grant_ref *kmap_op)
+{
+	unsigned long flags;
+	unsigned long pfn;
+	unsigned long uninitialized_var(address);
+	unsigned level;
+	pte_t *ptep = NULL;
+
+	pfn = page_to_pfn(page);
+	if (!PageHighMem(page)) {
+		address = (unsigned long)__va(pfn << PAGE_SHIFT);
+		ptep = lookup_address(address, &level);
+		if (WARN(ptep == NULL || level != PG_LEVEL_4K,
+					"m2p_add_override: pfn %lx not mapped", pfn))
+			return -EINVAL;
+	}
+	WARN_ON(PagePrivate(page));
+	SetPagePrivate(page);
+	set_page_private(page, mfn);
+	page->index = pfn_to_mfn(pfn);
+
+	if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn))))
+		return -ENOMEM;
+
+	if (kmap_op != NULL) {
+		if (!PageHighMem(page)) {
+			struct multicall_space mcs =
+				xen_mc_entry(sizeof(*kmap_op));
+
+			MULTI_grant_table_op(mcs.mc,
+					GNTTABOP_map_grant_ref, kmap_op, 1);
+
+			xen_mc_issue(PARAVIRT_LAZY_MMU);
+		}
+		/* let's use dev_bus_addr to record the old mfn instead */
+		kmap_op->dev_bus_addr = page->index;
+		page->index = (unsigned long) kmap_op;
+	}
+	spin_lock_irqsave(&m2p_override_lock, flags);
+	list_add(&page->lru,  &m2p_overrides[mfn_hash(mfn)]);
+	spin_unlock_irqrestore(&m2p_override_lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(m2p_add_override);
+int m2p_remove_override(struct page *page, bool clear_pte)
+{
+	unsigned long flags;
+	unsigned long mfn;
+	unsigned long pfn;
+	unsigned long uninitialized_var(address);
+	unsigned level;
+	pte_t *ptep = NULL;
+
+	pfn = page_to_pfn(page);
+	mfn = get_phys_to_machine(pfn);
+	if (mfn == INVALID_P2M_ENTRY || !(mfn & FOREIGN_FRAME_BIT))
+		return -EINVAL;
+
+	if (!PageHighMem(page)) {
+		address = (unsigned long)__va(pfn << PAGE_SHIFT);
+		ptep = lookup_address(address, &level);
+
+		if (WARN(ptep == NULL || level != PG_LEVEL_4K,
+					"m2p_remove_override: pfn %lx not mapped", pfn))
+			return -EINVAL;
+	}
+
+	spin_lock_irqsave(&m2p_override_lock, flags);
+	list_del(&page->lru);
+	spin_unlock_irqrestore(&m2p_override_lock, flags);
+	WARN_ON(!PagePrivate(page));
+	ClearPagePrivate(page);
+
+	if (clear_pte) {
+		struct gnttab_map_grant_ref *map_op =
+			(struct gnttab_map_grant_ref *) page->index;
+		set_phys_to_machine(pfn, map_op->dev_bus_addr);
+		if (!PageHighMem(page)) {
+			struct multicall_space mcs;
+			struct gnttab_unmap_grant_ref *unmap_op;
+
+			/*
+			 * It might be that we queued all the m2p grant table
+			 * hypercalls in a multicall, then m2p_remove_override
+			 * get called before the multicall has actually been
+			 * issued. In this case handle is going to -1 because
+			 * it hasn't been modified yet.
+			 */
+			if (map_op->handle == -1)
+				xen_mc_flush();
+			/*
+			 * Now if map_op->handle is negative it means that the
+			 * hypercall actually returned an error.
+			 */
+			if (map_op->handle == GNTST_general_error) {
+				printk(KERN_WARNING "m2p_remove_override: "
+						"pfn %lx mfn %lx, failed to modify kernel mappings",
+						pfn, mfn);
+				return -1;
+			}
+
+			mcs = xen_mc_entry(
+					sizeof(struct gnttab_unmap_grant_ref));
+			unmap_op = mcs.args;
+			unmap_op->host_addr = map_op->host_addr;
+			unmap_op->handle = map_op->handle;
+			unmap_op->dev_bus_addr = 0;
+
+			MULTI_grant_table_op(mcs.mc,
+					GNTTABOP_unmap_grant_ref, unmap_op, 1);
+
+			xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+			set_pte_at(&init_mm, address, ptep,
+					pfn_pte(pfn, PAGE_KERNEL));
+			__flush_tlb_single(address);
+			map_op->host_addr = 0;
+		}
+	} else
+		set_phys_to_machine(pfn, page->index);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(m2p_remove_override);
+
+struct page *m2p_find_override(unsigned long mfn)
+{
+	unsigned long flags;
+	struct list_head *bucket = &m2p_overrides[mfn_hash(mfn)];
+	struct page *p, *ret;
+
+	ret = NULL;
+
+	spin_lock_irqsave(&m2p_override_lock, flags);
+
+	list_for_each_entry(p, bucket, lru) {
+		if (page_private(p) == mfn) {
+			ret = p;
+			break;
+		}
+	}
+
+	spin_unlock_irqrestore(&m2p_override_lock, flags);
+
+	return ret;
+}
+
+unsigned long m2p_find_override_pfn(unsigned long mfn, unsigned long pfn)
+{
+	struct page *p = m2p_find_override(mfn);
+	unsigned long ret = pfn;
+
+	if (p)
+		ret = page_to_pfn(p);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(m2p_find_override_pfn);
+
+#ifdef CONFIG_XEN_DEBUG_FS
+#include <linux/debugfs.h>
+#include "debugfs.h"
+static int p2m_dump_show(struct seq_file *m, void *v)
+{
+	static const char * const level_name[] = { "top", "middle",
+						"entry", "abnormal", "error"};
+#define TYPE_IDENTITY 0
+#define TYPE_MISSING 1
+#define TYPE_PFN 2
+#define TYPE_UNKNOWN 3
+	static const char * const type_name[] = {
+				[TYPE_IDENTITY] = "identity",
+				[TYPE_MISSING] = "missing",
+				[TYPE_PFN] = "pfn",
+				[TYPE_UNKNOWN] = "abnormal"};
+	unsigned long pfn, prev_pfn_type = 0, prev_pfn_level = 0;
+	unsigned int uninitialized_var(prev_level);
+	unsigned int uninitialized_var(prev_type);
+
+	if (!p2m_top)
+		return 0;
+
+	for (pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn++) {
+		unsigned topidx = p2m_top_index(pfn);
+		unsigned mididx = p2m_mid_index(pfn);
+		unsigned idx = p2m_index(pfn);
+		unsigned lvl, type;
+
+		lvl = 4;
+		type = TYPE_UNKNOWN;
+		if (p2m_top[topidx] == p2m_mid_missing) {
+			lvl = 0; type = TYPE_MISSING;
+		} else if (p2m_top[topidx] == NULL) {
+			lvl = 0; type = TYPE_UNKNOWN;
+		} else if (p2m_top[topidx][mididx] == NULL) {
+			lvl = 1; type = TYPE_UNKNOWN;
+		} else if (p2m_top[topidx][mididx] == p2m_identity) {
+			lvl = 1; type = TYPE_IDENTITY;
+		} else if (p2m_top[topidx][mididx] == p2m_missing) {
+			lvl = 1; type = TYPE_MISSING;
+		} else if (p2m_top[topidx][mididx][idx] == 0) {
+			lvl = 2; type = TYPE_UNKNOWN;
+		} else if (p2m_top[topidx][mididx][idx] == IDENTITY_FRAME(pfn)) {
+			lvl = 2; type = TYPE_IDENTITY;
+		} else if (p2m_top[topidx][mididx][idx] == INVALID_P2M_ENTRY) {
+			lvl = 2; type = TYPE_MISSING;
+		} else if (p2m_top[topidx][mididx][idx] == pfn) {
+			lvl = 2; type = TYPE_PFN;
+		} else if (p2m_top[topidx][mididx][idx] != pfn) {
+			lvl = 2; type = TYPE_PFN;
+		}
+		if (pfn == 0) {
+			prev_level = lvl;
+			prev_type = type;
+		}
+		if (pfn == MAX_DOMAIN_PAGES-1) {
+			lvl = 3;
+			type = TYPE_UNKNOWN;
+		}
+		if (prev_type != type) {
+			seq_printf(m, " [0x%lx->0x%lx] %s\n",
+				prev_pfn_type, pfn, type_name[prev_type]);
+			prev_pfn_type = pfn;
+			prev_type = type;
+		}
+		if (prev_level != lvl) {
+			seq_printf(m, " [0x%lx->0x%lx] level %s\n",
+				prev_pfn_level, pfn, level_name[prev_level]);
+			prev_pfn_level = pfn;
+			prev_level = lvl;
+		}
+	}
+	return 0;
+#undef TYPE_IDENTITY
+#undef TYPE_MISSING
+#undef TYPE_PFN
+#undef TYPE_UNKNOWN
+}
+
+static int p2m_dump_open(struct inode *inode, struct file *filp)
+{
+	return single_open(filp, p2m_dump_show, NULL);
+}
+
+static const struct file_operations p2m_dump_fops = {
+	.open		= p2m_dump_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static struct dentry *d_mmu_debug;
+
+static int __init xen_p2m_debugfs(void)
+{
+	struct dentry *d_xen = xen_init_debugfs();
+
+	if (d_xen == NULL)
+		return -ENOMEM;
+
+	d_mmu_debug = debugfs_create_dir("mmu", d_xen);
+
+	debugfs_create_file("p2m", 0600, d_mmu_debug, NULL, &p2m_dump_fops);
+	return 0;
+}
+fs_initcall(xen_p2m_debugfs);
+#endif /* CONFIG_XEN_DEBUG_FS */
diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c
new file mode 100644
index 00000000..967633ad
--- /dev/null
+++ b/arch/x86/xen/pci-swiotlb-xen.c
@@ -0,0 +1,67 @@
+/* Glue code to lib/swiotlb-xen.c */
+
+#include <linux/dma-mapping.h>
+#include <linux/pci.h>
+#include <xen/swiotlb-xen.h>
+
+#include <asm/xen/hypervisor.h>
+#include <xen/xen.h>
+#include <asm/iommu_table.h>
+
+int xen_swiotlb __read_mostly;
+
+static struct dma_map_ops xen_swiotlb_dma_ops = {
+	.mapping_error = xen_swiotlb_dma_mapping_error,
+	.alloc = xen_swiotlb_alloc_coherent,
+	.free = xen_swiotlb_free_coherent,
+	.sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu,
+	.sync_single_for_device = xen_swiotlb_sync_single_for_device,
+	.sync_sg_for_cpu = xen_swiotlb_sync_sg_for_cpu,
+	.sync_sg_for_device = xen_swiotlb_sync_sg_for_device,
+	.map_sg = xen_swiotlb_map_sg_attrs,
+	.unmap_sg = xen_swiotlb_unmap_sg_attrs,
+	.map_page = xen_swiotlb_map_page,
+	.unmap_page = xen_swiotlb_unmap_page,
+	.dma_supported = xen_swiotlb_dma_supported,
+};
+
+/*
+ * pci_xen_swiotlb_detect - set xen_swiotlb to 1 if necessary
+ *
+ * This returns non-zero if we are forced to use xen_swiotlb (by the boot
+ * option).
+ */
+int __init pci_xen_swiotlb_detect(void)
+{
+
+	/* If running as PV guest, either iommu=soft, or swiotlb=force will
+	 * activate this IOMMU. If running as PV privileged, activate it
+	 * irregardless.
+	 */
+	if ((xen_initial_domain() || swiotlb || swiotlb_force) &&
+	    (xen_pv_domain()))
+		xen_swiotlb = 1;
+
+	/* If we are running under Xen, we MUST disable the native SWIOTLB.
+	 * Don't worry about swiotlb_force flag activating the native, as
+	 * the 'swiotlb' flag is the only one turning it on. */
+	if (xen_pv_domain())
+		swiotlb = 0;
+
+	return xen_swiotlb;
+}
+
+void __init pci_xen_swiotlb_init(void)
+{
+	if (xen_swiotlb) {
+		xen_swiotlb_init(1);
+		dma_ops = &xen_swiotlb_dma_ops;
+
+		/* Make sure ACS will be enabled */
+		pci_request_acs();
+	}
+}
+IOMMU_INIT_FINISH(pci_xen_swiotlb_detect,
+		  0,
+		  pci_xen_swiotlb_init,
+		  0);
diff --git a/arch/x86/xen/platform-pci-unplug.c b/arch/x86/xen/platform-pci-unplug.c
new file mode 100644
index 00000000..ffcf2615
--- /dev/null
+++ b/arch/x86/xen/platform-pci-unplug.c
@@ -0,0 +1,143 @@
+/******************************************************************************
+ * platform-pci-unplug.c
+ *
+ * Xen platform PCI device driver
+ * Copyright (c) 2010, Citrix
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/module.h>
+
+#include <xen/platform_pci.h>
+
+#define XEN_PLATFORM_ERR_MAGIC -1
+#define XEN_PLATFORM_ERR_PROTOCOL -2
+#define XEN_PLATFORM_ERR_BLACKLIST -3
+
+/* store the value of xen_emul_unplug after the unplug is done */
+int xen_platform_pci_unplug;
+EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);
+#ifdef CONFIG_XEN_PVHVM
+static int xen_emul_unplug;
+
+static int check_platform_magic(void)
+{
+	short magic;
+	char protocol;
+
+	magic = inw(XEN_IOPORT_MAGIC);
+	if (magic != XEN_IOPORT_MAGIC_VAL) {
+		printk(KERN_ERR "Xen Platform PCI: unrecognised magic value\n");
+		return XEN_PLATFORM_ERR_MAGIC;
+	}
+
+	protocol = inb(XEN_IOPORT_PROTOVER);
+
+	printk(KERN_DEBUG "Xen Platform PCI: I/O protocol version %d\n",
+			protocol);
+
+	switch (protocol) {
+	case 1:
+		outw(XEN_IOPORT_LINUX_PRODNUM, XEN_IOPORT_PRODNUM);
+		outl(XEN_IOPORT_LINUX_DRVVER, XEN_IOPORT_DRVVER);
+		if (inw(XEN_IOPORT_MAGIC) != XEN_IOPORT_MAGIC_VAL) {
+			printk(KERN_ERR "Xen Platform: blacklisted by host\n");
+			return XEN_PLATFORM_ERR_BLACKLIST;
+		}
+		break;
+	default:
+		printk(KERN_WARNING "Xen Platform PCI: unknown I/O protocol version");
+		return XEN_PLATFORM_ERR_PROTOCOL;
+	}
+
+	return 0;
+}
+
+void xen_unplug_emulated_devices(void)
+{
+	int r;
+
+	/* user explicitly requested no unplug */
+	if (xen_emul_unplug & XEN_UNPLUG_NEVER)
+		return;
+	/* check the version of the xen platform PCI device */
+	r = check_platform_magic();
+	/* If the version matches enable the Xen platform PCI driver.
+	 * Also enable the Xen platform PCI driver if the host does
+	 * not support the unplug protocol (XEN_PLATFORM_ERR_MAGIC)
+	 * but the user told us that unplugging is unnecessary. */
+	if (r && !(r == XEN_PLATFORM_ERR_MAGIC &&
+			(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY)))
+		return;
+	/* Set the default value of xen_emul_unplug depending on whether or
+	 * not the Xen PV frontends and the Xen platform PCI driver have
+	 * been compiled for this kernel (modules or built-in are both OK). */
+	if (!xen_emul_unplug) {
+		if (xen_must_unplug_nics()) {
+			printk(KERN_INFO "Netfront and the Xen platform PCI driver have "
+					"been compiled for this kernel: unplug emulated NICs.\n");
+			xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
+		}
+		if (xen_must_unplug_disks()) {
+			printk(KERN_INFO "Blkfront and the Xen platform PCI driver have "
+					"been compiled for this kernel: unplug emulated disks.\n"
+					"You might have to change the root device\n"
+					"from /dev/hd[a-d] to /dev/xvd[a-d]\n"
+					"in your root= kernel command line option\n");
+			xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
+		}
+	}
+	/* Now unplug the emulated devices */
+	if (!(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY))
+		outw(xen_emul_unplug, XEN_IOPORT_UNPLUG);
+	xen_platform_pci_unplug = xen_emul_unplug;
+}
+
+static int __init parse_xen_emul_unplug(char *arg)
+{
+	char *p, *q;
+	int l;
+
+	for (p = arg; p; p = q) {
+		q = strchr(p, ',');
+		if (q) {
+			l = q - p;
+			q++;
+		} else {
+			l = strlen(p);
+		}
+		if (!strncmp(p, "all", l))
+			xen_emul_unplug |= XEN_UNPLUG_ALL;
+		else if (!strncmp(p, "ide-disks", l))
+			xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
+		else if (!strncmp(p, "aux-ide-disks", l))
+			xen_emul_unplug |= XEN_UNPLUG_AUX_IDE_DISKS;
+		else if (!strncmp(p, "nics", l))
+			xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
+		else if (!strncmp(p, "unnecessary", l))
+			xen_emul_unplug |= XEN_UNPLUG_UNNECESSARY;
+		else if (!strncmp(p, "never", l))
+			xen_emul_unplug |= XEN_UNPLUG_NEVER;
+		else
+			printk(KERN_WARNING "unrecognised option '%s' "
+				 "in parameter 'xen_emul_unplug'\n", p);
+	}
+	return 0;
+}
+early_param("xen_emul_unplug", parse_xen_emul_unplug);
+#endif
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
new file mode 100644
index 00000000..1ba8dff2
--- /dev/null
+++ b/arch/x86/xen/setup.c
@@ -0,0 +1,427 @@
+/*
+ * Machine specific setup for xen
+ *
+ * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
+ */
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/pm.h>
+#include <linux/memblock.h>
+#include <linux/cpuidle.h>
+#include <linux/cpufreq.h>
+
+#include <asm/elf.h>
+#include <asm/vdso.h>
+#include <asm/e820.h>
+#include <asm/setup.h>
+#include <asm/acpi.h>
+#include <asm/xen/hypervisor.h>
+#include <asm/xen/hypercall.h>
+
+#include <xen/xen.h>
+#include <xen/page.h>
+#include <xen/interface/callback.h>
+#include <xen/interface/memory.h>
+#include <xen/interface/physdev.h>
+#include <xen/features.h>
+
+#include "xen-ops.h"
+#include "vdso.h"
+
+/* These are code, but not functions.  Defined in entry.S */
+extern const char xen_hypervisor_callback[];
+extern const char xen_failsafe_callback[];
+extern void xen_sysenter_target(void);
+extern void xen_syscall_target(void);
+extern void xen_syscall32_target(void);
+
+/* Amount of extra memory space we add to the e820 ranges */
+struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;
+
+/* Number of pages released from the initial allocation. */
+unsigned long xen_released_pages;
+
+/* 
+ * The maximum amount of extra memory compared to the base size.  The
+ * main scaling factor is the size of struct page.  At extreme ratios
+ * of base:extra, all the base memory can be filled with page
+ * structures for the extra memory, leaving no space for anything
+ * else.
+ * 
+ * 10x seems like a reasonable balance between scaling flexibility and
+ * leaving a practically usable system.
+ */
+#define EXTRA_MEM_RATIO		(10)
+
+static void __init xen_add_extra_mem(u64 start, u64 size)
+{
+	unsigned long pfn;
+	int i;
+
+	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
+		/* Add new region. */
+		if (xen_extra_mem[i].size == 0) {
+			xen_extra_mem[i].start = start;
+			xen_extra_mem[i].size  = size;
+			break;
+		}
+		/* Append to existing region. */
+		if (xen_extra_mem[i].start + xen_extra_mem[i].size == start) {
+			xen_extra_mem[i].size += size;
+			break;
+		}
+	}
+	if (i == XEN_EXTRA_MEM_MAX_REGIONS)
+		printk(KERN_WARNING "Warning: not enough extra memory regions\n");
+
+	memblock_reserve(start, size);
+
+	xen_max_p2m_pfn = PFN_DOWN(start + size);
+
+	for (pfn = PFN_DOWN(start); pfn <= xen_max_p2m_pfn; pfn++)
+		__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
+}
+
+static unsigned long __init xen_release_chunk(unsigned long start,
+					      unsigned long end)
+{
+	struct xen_memory_reservation reservation = {
+		.address_bits = 0,
+		.extent_order = 0,
+		.domid        = DOMID_SELF
+	};
+	unsigned long len = 0;
+	unsigned long pfn;
+	int ret;
+
+	for(pfn = start; pfn < end; pfn++) {
+		unsigned long mfn = pfn_to_mfn(pfn);
+
+		/* Make sure pfn exists to start with */
+		if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn)
+			continue;
+
+		set_xen_guest_handle(reservation.extent_start, &mfn);
+		reservation.nr_extents = 1;
+
+		ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation,
+					   &reservation);
+		WARN(ret != 1, "Failed to release pfn %lx err=%d\n", pfn, ret);
+		if (ret == 1) {
+			__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
+			len++;
+		}
+	}
+	printk(KERN_INFO "Freeing  %lx-%lx pfn range: %lu pages freed\n",
+	       start, end, len);
+
+	return len;
+}
+
+static unsigned long __init xen_set_identity_and_release(
+	const struct e820entry *list, size_t map_size, unsigned long nr_pages)
+{
+	phys_addr_t start = 0;
+	unsigned long released = 0;
+	unsigned long identity = 0;
+	const struct e820entry *entry;
+	int i;
+
+	/*
+	 * Combine non-RAM regions and gaps until a RAM region (or the
+	 * end of the map) is reached, then set the 1:1 map and
+	 * release the pages (if available) in those non-RAM regions.
+	 *
+	 * The combined non-RAM regions are rounded to a whole number
+	 * of pages so any partial pages are accessible via the 1:1
+	 * mapping.  This is needed for some BIOSes that put (for
+	 * example) the DMI tables in a reserved region that begins on
+	 * a non-page boundary.
+	 */
+	for (i = 0, entry = list; i < map_size; i++, entry++) {
+		phys_addr_t end = entry->addr + entry->size;
+
+		if (entry->type == E820_RAM || i == map_size - 1) {
+			unsigned long start_pfn = PFN_DOWN(start);
+			unsigned long end_pfn = PFN_UP(end);
+
+			if (entry->type == E820_RAM)
+				end_pfn = PFN_UP(entry->addr);
+
+			if (start_pfn < end_pfn) {
+				if (start_pfn < nr_pages)
+					released += xen_release_chunk(
+						start_pfn, min(end_pfn, nr_pages));
+
+				identity += set_phys_range_identity(
+					start_pfn, end_pfn);
+			}
+			start = end;
+		}
+	}
+
+	printk(KERN_INFO "Released %lu pages of unused memory\n", released);
+	printk(KERN_INFO "Set %ld page(s) to 1-1 mapping\n", identity);
+
+	return released;
+}
+
+static unsigned long __init xen_get_max_pages(void)
+{
+	unsigned long max_pages = MAX_DOMAIN_PAGES;
+	domid_t domid = DOMID_SELF;
+	int ret;
+
+	/*
+	 * For the initial domain we use the maximum reservation as
+	 * the maximum page.
+	 *
+	 * For guest domains the current maximum reservation reflects
+	 * the current maximum rather than the static maximum. In this
+	 * case the e820 map provided to us will cover the static
+	 * maximum region.
+	 */
+	if (xen_initial_domain()) {
+		ret = HYPERVISOR_memory_op(XENMEM_maximum_reservation, &domid);
+		if (ret > 0)
+			max_pages = ret;
+	}
+
+	return min(max_pages, MAX_DOMAIN_PAGES);
+}
+
+static void xen_align_and_add_e820_region(u64 start, u64 size, int type)
+{
+	u64 end = start + size;
+
+	/* Align RAM regions to page boundaries. */
+	if (type == E820_RAM) {
+		start = PAGE_ALIGN(start);
+		end &= ~((u64)PAGE_SIZE - 1);
+	}
+
+	e820_add_region(start, end - start, type);
+}
+
+/**
+ * machine_specific_memory_setup - Hook for machine specific memory setup.
+ **/
+char * __init xen_memory_setup(void)
+{
+	static struct e820entry map[E820MAX] __initdata;
+
+	unsigned long max_pfn = xen_start_info->nr_pages;
+	unsigned long long mem_end;
+	int rc;
+	struct xen_memory_map memmap;
+	unsigned long max_pages;
+	unsigned long extra_pages = 0;
+	int i;
+	int op;
+
+	max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
+	mem_end = PFN_PHYS(max_pfn);
+
+	memmap.nr_entries = E820MAX;
+	set_xen_guest_handle(memmap.buffer, map);
+
+	op = xen_initial_domain() ?
+		XENMEM_machine_memory_map :
+		XENMEM_memory_map;
+	rc = HYPERVISOR_memory_op(op, &memmap);
+	if (rc == -ENOSYS) {
+		BUG_ON(xen_initial_domain());
+		memmap.nr_entries = 1;
+		map[0].addr = 0ULL;
+		map[0].size = mem_end;
+		/* 8MB slack (to balance backend allocations). */
+		map[0].size += 8ULL << 20;
+		map[0].type = E820_RAM;
+		rc = 0;
+	}
+	BUG_ON(rc);
+
+	/* Make sure the Xen-supplied memory map is well-ordered. */
+	sanitize_e820_map(map, memmap.nr_entries, &memmap.nr_entries);
+
+	max_pages = xen_get_max_pages();
+	if (max_pages > max_pfn)
+		extra_pages += max_pages - max_pfn;
+
+	/*
+	 * Set P2M for all non-RAM pages and E820 gaps to be identity
+	 * type PFNs.  Any RAM pages that would be made inaccesible by
+	 * this are first released.
+	 */
+	xen_released_pages = xen_set_identity_and_release(
+		map, memmap.nr_entries, max_pfn);
+	extra_pages += xen_released_pages;
+
+	/*
+	 * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
+	 * factor the base size.  On non-highmem systems, the base
+	 * size is the full initial memory allocation; on highmem it
+	 * is limited to the max size of lowmem, so that it doesn't
+	 * get completely filled.
+	 *
+	 * In principle there could be a problem in lowmem systems if
+	 * the initial memory is also very large with respect to
+	 * lowmem, but we won't try to deal with that here.
+	 */
+	extra_pages = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
+			  extra_pages);
+
+	i = 0;
+	while (i < memmap.nr_entries) {
+		u64 addr = map[i].addr;
+		u64 size = map[i].size;
+		u32 type = map[i].type;
+
+		if (type == E820_RAM) {
+			if (addr < mem_end) {
+				size = min(size, mem_end - addr);
+			} else if (extra_pages) {
+				size = min(size, (u64)extra_pages * PAGE_SIZE);
+				extra_pages -= size / PAGE_SIZE;
+				xen_add_extra_mem(addr, size);
+			} else
+				type = E820_UNUSABLE;
+		}
+
+		xen_align_and_add_e820_region(addr, size, type);
+
+		map[i].addr += size;
+		map[i].size -= size;
+		if (map[i].size == 0)
+			i++;
+	}
+
+	/*
+	 * In domU, the ISA region is normal, usable memory, but we
+	 * reserve ISA memory anyway because too many things poke
+	 * about in there.
+	 */
+	e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
+			E820_RESERVED);
+
+	/*
+	 * Reserve Xen bits:
+	 *  - mfn_list
+	 *  - xen_start_info
+	 * See comment above "struct start_info" in <xen/interface/xen.h>
+	 */
+	memblock_reserve(__pa(xen_start_info->mfn_list),
+			 xen_start_info->pt_base - xen_start_info->mfn_list);
+
+	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
+
+	return "Xen";
+}
+
+/*
+ * Set the bit indicating "nosegneg" library variants should be used.
+ * We only need to bother in pure 32-bit mode; compat 32-bit processes
+ * can have un-truncated segments, so wrapping around is allowed.
+ */
+static void __init fiddle_vdso(void)
+{
+#ifdef CONFIG_X86_32
+	u32 *mask;
+	mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
+	*mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
+	mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
+	*mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
+#endif
+}
+
+static int __cpuinit register_callback(unsigned type, const void *func)
+{
+	struct callback_register callback = {
+		.type = type,
+		.address = XEN_CALLBACK(__KERNEL_CS, func),
+		.flags = CALLBACKF_mask_events,
+	};
+
+	return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
+}
+
+void __cpuinit xen_enable_sysenter(void)
+{
+	int ret;
+	unsigned sysenter_feature;
+
+#ifdef CONFIG_X86_32
+	sysenter_feature = X86_FEATURE_SEP;
+#else
+	sysenter_feature = X86_FEATURE_SYSENTER32;
+#endif
+
+	if (!boot_cpu_has(sysenter_feature))
+		return;
+
+	ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
+	if(ret != 0)
+		setup_clear_cpu_cap(sysenter_feature);
+}
+
+void __cpuinit xen_enable_syscall(void)
+{
+#ifdef CONFIG_X86_64
+	int ret;
+
+	ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
+	if (ret != 0) {
+		printk(KERN_ERR "Failed to set syscall callback: %d\n", ret);
+		/* Pretty fatal; 64-bit userspace has no other
+		   mechanism for syscalls. */
+	}
+
+	if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
+		ret = register_callback(CALLBACKTYPE_syscall32,
+					xen_syscall32_target);
+		if (ret != 0)
+			setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
+	}
+#endif /* CONFIG_X86_64 */
+}
+
+void __init xen_arch_setup(void)
+{
+	xen_panic_handler_init();
+
+	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
+	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);
+
+	if (!xen_feature(XENFEAT_auto_translated_physmap))
+		HYPERVISOR_vm_assist(VMASST_CMD_enable,
+				     VMASST_TYPE_pae_extended_cr3);
+
+	if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
+	    register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
+		BUG();
+
+	xen_enable_sysenter();
+	xen_enable_syscall();
+
+#ifdef CONFIG_ACPI
+	if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
+		printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
+		disable_acpi();
+	}
+#endif
+
+	memcpy(boot_command_line, xen_start_info->cmd_line,
+	       MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
+	       COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
+
+	/* Set up idle, making sure it calls safe_halt() pvop */
+#ifdef CONFIG_X86_32
+	boot_cpu_data.hlt_works_ok = 1;
+#endif
+	disable_cpuidle();
+	disable_cpufreq();
+	WARN_ON(set_pm_idle_to_default());
+	fiddle_vdso();
+}
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
new file mode 100644
index 00000000..0503c0c4
--- /dev/null
+++ b/arch/x86/xen/smp.c
@@ -0,0 +1,592 @@
+/*
+ * Xen SMP support
+ *
+ * This file implements the Xen versions of smp_ops.  SMP under Xen is
+ * very straightforward.  Bringing a CPU up is simply a matter of
+ * loading its initial context and setting it running.
+ *
+ * IPIs are handled through the Xen event mechanism.
+ *
+ * Because virtual CPUs can be scheduled onto any real CPU, there's no
+ * useful topology information for the kernel to make use of.  As a
+ * result, all CPUs are treated as if they're single-core and
+ * single-threaded.
+ */
+#include <linux/sched.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/smp.h>
+
+#include <asm/paravirt.h>
+#include <asm/desc.h>
+#include <asm/pgtable.h>
+#include <asm/cpu.h>
+
+#include <xen/interface/xen.h>
+#include <xen/interface/vcpu.h>
+
+#include <asm/xen/interface.h>
+#include <asm/xen/hypercall.h>
+
+#include <xen/xen.h>
+#include <xen/page.h>
+#include <xen/events.h>
+
+#include <xen/hvc-console.h>
+#include "xen-ops.h"
+#include "mmu.h"
+
+cpumask_var_t xen_cpu_initialized_map;
+
+static DEFINE_PER_CPU(int, xen_resched_irq);
+static DEFINE_PER_CPU(int, xen_callfunc_irq);
+static DEFINE_PER_CPU(int, xen_callfuncsingle_irq);
+static DEFINE_PER_CPU(int, xen_debug_irq) = -1;
+
+static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id);
+static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id);
+
+/*
+ * Reschedule call back.
+ */
+static irqreturn_t xen_reschedule_interrupt(int irq, void *dev_id)
+{
+	inc_irq_stat(irq_resched_count);
+	scheduler_ipi();
+
+	return IRQ_HANDLED;
+}
+
+static void __cpuinit cpu_bringup(void)
+{
+	int cpu;
+
+	cpu_init();
+	touch_softlockup_watchdog();
+	preempt_disable();
+
+	xen_enable_sysenter();
+	xen_enable_syscall();
+
+	cpu = smp_processor_id();
+	smp_store_cpu_info(cpu);
+	cpu_data(cpu).x86_max_cores = 1;
+	set_cpu_sibling_map(cpu);
+
+	xen_setup_cpu_clockevents();
+
+	notify_cpu_starting(cpu);
+
+	ipi_call_lock();
+	set_cpu_online(cpu, true);
+	ipi_call_unlock();
+
+	this_cpu_write(cpu_state, CPU_ONLINE);
+
+	wmb();
+
+	/* We can take interrupts now: we're officially "up". */
+	local_irq_enable();
+
+	wmb();			/* make sure everything is out */
+}
+
+static void __cpuinit cpu_bringup_and_idle(void)
+{
+	cpu_bringup();
+	cpu_idle();
+}
+
+static int xen_smp_intr_init(unsigned int cpu)
+{
+	int rc;
+	const char *resched_name, *callfunc_name, *debug_name;
+
+	resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
+	rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
+				    cpu,
+				    xen_reschedule_interrupt,
+				    IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
+				    resched_name,
+				    NULL);
+	if (rc < 0)
+		goto fail;
+	per_cpu(xen_resched_irq, cpu) = rc;
+
+	callfunc_name = kasprintf(GFP_KERNEL, "callfunc%d", cpu);
+	rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR,
+				    cpu,
+				    xen_call_function_interrupt,
+				    IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
+				    callfunc_name,
+				    NULL);
+	if (rc < 0)
+		goto fail;
+	per_cpu(xen_callfunc_irq, cpu) = rc;
+
+	debug_name = kasprintf(GFP_KERNEL, "debug%d", cpu);
+	rc = bind_virq_to_irqhandler(VIRQ_DEBUG, cpu, xen_debug_interrupt,
+				     IRQF_DISABLED | IRQF_PERCPU | IRQF_NOBALANCING,
+				     debug_name, NULL);
+	if (rc < 0)
+		goto fail;
+	per_cpu(xen_debug_irq, cpu) = rc;
+
+	callfunc_name = kasprintf(GFP_KERNEL, "callfuncsingle%d", cpu);
+	rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_SINGLE_VECTOR,
+				    cpu,
+				    xen_call_function_single_interrupt,
+				    IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
+				    callfunc_name,
+				    NULL);
+	if (rc < 0)
+		goto fail;
+	per_cpu(xen_callfuncsingle_irq, cpu) = rc;
+
+	return 0;
+
+ fail:
+	if (per_cpu(xen_resched_irq, cpu) >= 0)
+		unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu), NULL);
+	if (per_cpu(xen_callfunc_irq, cpu) >= 0)
+		unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu), NULL);
+	if (per_cpu(xen_debug_irq, cpu) >= 0)
+		unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu), NULL);
+	if (per_cpu(xen_callfuncsingle_irq, cpu) >= 0)
+		unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu),
+				       NULL);
+
+	return rc;
+}
+
+static void __init xen_fill_possible_map(void)
+{
+	int i, rc;
+
+	if (xen_initial_domain())
+		return;
+
+	for (i = 0; i < nr_cpu_ids; i++) {
+		rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);
+		if (rc >= 0) {
+			num_processors++;
+			set_cpu_possible(i, true);
+		}
+	}
+}
+
+static void __init xen_filter_cpu_maps(void)
+{
+	int i, rc;
+	unsigned int subtract = 0;
+
+	if (!xen_initial_domain())
+		return;
+
+	num_processors = 0;
+	disabled_cpus = 0;
+	for (i = 0; i < nr_cpu_ids; i++) {
+		rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);
+		if (rc >= 0) {
+			num_processors++;
+			set_cpu_possible(i, true);
+		} else {
+			set_cpu_possible(i, false);
+			set_cpu_present(i, false);
+			subtract++;
+		}
+	}
+#ifdef CONFIG_HOTPLUG_CPU
+	/* This is akin to using 'nr_cpus' on the Linux command line.
+	 * Which is OK as when we use 'dom0_max_vcpus=X' we can only
+	 * have up to X, while nr_cpu_ids is greater than X. This
+	 * normally is not a problem, except when CPU hotplugging
+	 * is involved and then there might be more than X CPUs
+	 * in the guest - which will not work as there is no
+	 * hypercall to expand the max number of VCPUs an already
+	 * running guest has. So cap it up to X. */
+	if (subtract)
+		nr_cpu_ids = nr_cpu_ids - subtract;
+#endif
+
+}
+
+static void __init xen_smp_prepare_boot_cpu(void)
+{
+	BUG_ON(smp_processor_id() != 0);
+	native_smp_prepare_boot_cpu();
+
+	/* We've switched to the "real" per-cpu gdt, so make sure the
+	   old memory can be recycled */
+	make_lowmem_page_readwrite(xen_initial_gdt);
+
+	xen_filter_cpu_maps();
+	xen_setup_vcpu_info_placement();
+}
+
+static void __init xen_smp_prepare_cpus(unsigned int max_cpus)
+{
+	unsigned cpu;
+	unsigned int i;
+
+	if (skip_ioapic_setup) {
+		char *m = (max_cpus == 0) ?
+			"The nosmp parameter is incompatible with Xen; " \
+			"use Xen dom0_max_vcpus=1 parameter" :
+			"The noapic parameter is incompatible with Xen";
+
+		xen_raw_printk(m);
+		panic(m);
+	}
+	xen_init_lock_cpu(0);
+
+	smp_store_cpu_info(0);
+	cpu_data(0).x86_max_cores = 1;
+
+	for_each_possible_cpu(i) {
+		zalloc_cpumask_var(&per_cpu(cpu_sibling_map, i), GFP_KERNEL);
+		zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL);
+		zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL);
+	}
+	set_cpu_sibling_map(0);
+
+	if (xen_smp_intr_init(0))
+		BUG();
+
+	if (!alloc_cpumask_var(&xen_cpu_initialized_map, GFP_KERNEL))
+		panic("could not allocate xen_cpu_initialized_map\n");
+
+	cpumask_copy(xen_cpu_initialized_map, cpumask_of(0));
+
+	/* Restrict the possible_map according to max_cpus. */
+	while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus)) {
+		for (cpu = nr_cpu_ids - 1; !cpu_possible(cpu); cpu--)
+			continue;
+		set_cpu_possible(cpu, false);
+	}
+
+	for_each_possible_cpu (cpu) {
+		struct task_struct *idle;
+
+		if (cpu == 0)
+			continue;
+
+		idle = fork_idle(cpu);
+		if (IS_ERR(idle))
+			panic("failed fork for CPU %d", cpu);
+
+		set_cpu_present(cpu, true);
+	}
+}
+
+static int __cpuinit
+cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
+{
+	struct vcpu_guest_context *ctxt;
+	struct desc_struct *gdt;
+	unsigned long gdt_mfn;
+
+	if (cpumask_test_and_set_cpu(cpu, xen_cpu_initialized_map))
+		return 0;
+
+	ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
+	if (ctxt == NULL)
+		return -ENOMEM;
+
+	gdt = get_cpu_gdt_table(cpu);
+
+	ctxt->flags = VGCF_IN_KERNEL;
+	ctxt->user_regs.ds = __USER_DS;
+	ctxt->user_regs.es = __USER_DS;
+	ctxt->user_regs.ss = __KERNEL_DS;
+#ifdef CONFIG_X86_32
+	ctxt->user_regs.fs = __KERNEL_PERCPU;
+	ctxt->user_regs.gs = __KERNEL_STACK_CANARY;
+#else
+	ctxt->gs_base_kernel = per_cpu_offset(cpu);
+#endif
+	ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle;
+	ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */
+
+	memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));
+
+	xen_copy_trap_info(ctxt->trap_ctxt);
+
+	ctxt->ldt_ents = 0;
+
+	BUG_ON((unsigned long)gdt & ~PAGE_MASK);
+
+	gdt_mfn = arbitrary_virt_to_mfn(gdt);
+	make_lowmem_page_readonly(gdt);
+	make_lowmem_page_readonly(mfn_to_virt(gdt_mfn));
+
+	ctxt->gdt_frames[0] = gdt_mfn;
+	ctxt->gdt_ents      = GDT_ENTRIES;
+
+	ctxt->user_regs.cs = __KERNEL_CS;
+	ctxt->user_regs.esp = idle->thread.sp0 - sizeof(struct pt_regs);
+
+	ctxt->kernel_ss = __KERNEL_DS;
+	ctxt->kernel_sp = idle->thread.sp0;
+
+#ifdef CONFIG_X86_32
+	ctxt->event_callback_cs     = __KERNEL_CS;
+	ctxt->failsafe_callback_cs  = __KERNEL_CS;
+#endif
+	ctxt->event_callback_eip    = (unsigned long)xen_hypervisor_callback;
+	ctxt->failsafe_callback_eip = (unsigned long)xen_failsafe_callback;
+
+	per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
+	ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));
+
+	if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
+		BUG();
+
+	kfree(ctxt);
+	return 0;
+}
+
+static int __cpuinit xen_cpu_up(unsigned int cpu)
+{
+	struct task_struct *idle = idle_task(cpu);
+	int rc;
+
+	per_cpu(current_task, cpu) = idle;
+#ifdef CONFIG_X86_32
+	irq_ctx_init(cpu);
+#else
+	clear_tsk_thread_flag(idle, TIF_FORK);
+	per_cpu(kernel_stack, cpu) =
+		(unsigned long)task_stack_page(idle) -
+		KERNEL_STACK_OFFSET + THREAD_SIZE;
+#endif
+	xen_setup_runstate_info(cpu);
+	xen_setup_timer(cpu);
+	xen_init_lock_cpu(cpu);
+
+	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
+
+	/* make sure interrupts start blocked */
+	per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1;
+
+	rc = cpu_initialize_context(cpu, idle);
+	if (rc)
+		return rc;
+
+	if (num_online_cpus() == 1)
+		alternatives_smp_switch(1);
+
+	rc = xen_smp_intr_init(cpu);
+	if (rc)
+		return rc;
+
+	rc = HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL);
+	BUG_ON(rc);
+
+	while(per_cpu(cpu_state, cpu) != CPU_ONLINE) {
+		HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
+		barrier();
+	}
+
+	return 0;
+}
+
+static void xen_smp_cpus_done(unsigned int max_cpus)
+{
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static int xen_cpu_disable(void)
+{
+	unsigned int cpu = smp_processor_id();
+	if (cpu == 0)
+		return -EBUSY;
+
+	cpu_disable_common();
+
+	load_cr3(swapper_pg_dir);
+	return 0;
+}
+
+static void xen_cpu_die(unsigned int cpu)
+{
+	while (HYPERVISOR_vcpu_op(VCPUOP_is_up, cpu, NULL)) {
+		current->state = TASK_UNINTERRUPTIBLE;
+		schedule_timeout(HZ/10);
+	}
+	unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu), NULL);
+	unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu), NULL);
+	unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu), NULL);
+	unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu), NULL);
+	xen_uninit_lock_cpu(cpu);
+	xen_teardown_timer(cpu);
+
+	if (num_online_cpus() == 1)
+		alternatives_smp_switch(0);
+}
+
+static void __cpuinit xen_play_dead(void) /* used only with HOTPLUG_CPU */
+{
+	play_dead_common();
+	HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
+	cpu_bringup();
+	/*
+	 * Balance out the preempt calls - as we are running in cpu_idle
+	 * loop which has been called at bootup from cpu_bringup_and_idle.
+	 * The cpucpu_bringup_and_idle called cpu_bringup which made a
+	 * preempt_disable() So this preempt_enable will balance it out.
+	 */
+	preempt_enable();
+}
+
+#else /* !CONFIG_HOTPLUG_CPU */
+static int xen_cpu_disable(void)
+{
+	return -ENOSYS;
+}
+
+static void xen_cpu_die(unsigned int cpu)
+{
+	BUG();
+}
+
+static void xen_play_dead(void)
+{
+	BUG();
+}
+
+#endif
+static void stop_self(void *v)
+{
+	int cpu = smp_processor_id();
+
+	/* make sure we're not pinning something down */
+	load_cr3(swapper_pg_dir);
+	/* should set up a minimal gdt */
+
+	set_cpu_online(cpu, false);
+
+	HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL);
+	BUG();
+}
+
+static void xen_stop_other_cpus(int wait)
+{
+	smp_call_function(stop_self, NULL, wait);
+}
+
+static void xen_smp_send_reschedule(int cpu)
+{
+	xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);
+}
+
+static void xen_send_IPI_mask(const struct cpumask *mask,
+			      enum ipi_vector vector)
+{
+	unsigned cpu;
+
+	for_each_cpu_and(cpu, mask, cpu_online_mask)
+		xen_send_IPI_one(cpu, vector);
+}
+
+static void xen_smp_send_call_function_ipi(const struct cpumask *mask)
+{
+	int cpu;
+
+	xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR);
+
+	/* Make sure other vcpus get a chance to run if they need to. */
+	for_each_cpu(cpu, mask) {
+		if (xen_vcpu_stolen(cpu)) {
+			HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
+			break;
+		}
+	}
+}
+
+static void xen_smp_send_call_function_single_ipi(int cpu)
+{
+	xen_send_IPI_mask(cpumask_of(cpu),
+			  XEN_CALL_FUNCTION_SINGLE_VECTOR);
+}
+
+static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id)
+{
+	irq_enter();
+	generic_smp_call_function_interrupt();
+	inc_irq_stat(irq_call_count);
+	irq_exit();
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id)
+{
+	irq_enter();
+	generic_smp_call_function_single_interrupt();
+	inc_irq_stat(irq_call_count);
+	irq_exit();
+
+	return IRQ_HANDLED;
+}
+
+static const struct smp_ops xen_smp_ops __initconst = {
+	.smp_prepare_boot_cpu = xen_smp_prepare_boot_cpu,
+	.smp_prepare_cpus = xen_smp_prepare_cpus,
+	.smp_cpus_done = xen_smp_cpus_done,
+
+	.cpu_up = xen_cpu_up,
+	.cpu_die = xen_cpu_die,
+	.cpu_disable = xen_cpu_disable,
+	.play_dead = xen_play_dead,
+
+	.stop_other_cpus = xen_stop_other_cpus,
+	.smp_send_reschedule = xen_smp_send_reschedule,
+
+	.send_call_func_ipi = xen_smp_send_call_function_ipi,
+	.send_call_func_single_ipi = xen_smp_send_call_function_single_ipi,
+};
+
+void __init xen_smp_init(void)
+{
+	smp_ops = xen_smp_ops;
+	xen_fill_possible_map();
+	xen_init_spinlocks();
+}
+
+static void __init xen_hvm_smp_prepare_cpus(unsigned int max_cpus)
+{
+	native_smp_prepare_cpus(max_cpus);
+	WARN_ON(xen_smp_intr_init(0));
+
+	xen_init_lock_cpu(0);
+}
+
+static int __cpuinit xen_hvm_cpu_up(unsigned int cpu)
+{
+	int rc;
+	rc = native_cpu_up(cpu);
+	WARN_ON (xen_smp_intr_init(cpu));
+	return rc;
+}
+
+static void xen_hvm_cpu_die(unsigned int cpu)
+{
+	unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu), NULL);
+	unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu), NULL);
+	unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu), NULL);
+	unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu), NULL);
+	native_cpu_die(cpu);
+}
+
+void __init xen_hvm_smp_init(void)
+{
+	if (!xen_have_vector_callback)
+		return;
+	smp_ops.smp_prepare_cpus = xen_hvm_smp_prepare_cpus;
+	smp_ops.smp_send_reschedule = xen_smp_send_reschedule;
+	smp_ops.cpu_up = xen_hvm_cpu_up;
+	smp_ops.cpu_die = xen_hvm_cpu_die;
+	smp_ops.send_call_func_ipi = xen_smp_send_call_function_ipi;
+	smp_ops.send_call_func_single_ipi = xen_smp_send_call_function_single_ipi;
+}
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
new file mode 100644
index 00000000..d69cc6c3
--- /dev/null
+++ b/arch/x86/xen/spinlock.c
@@ -0,0 +1,454 @@
+/*
+ * Split spinlock implementation out into its own file, so it can be
+ * compiled in a FTRACE-compatible way.
+ */
+#include <linux/kernel_stat.h>
+#include <linux/spinlock.h>
+#include <linux/debugfs.h>
+#include <linux/log2.h>
+#include <linux/gfp.h>
+
+#include <asm/paravirt.h>
+
+#include <xen/interface/xen.h>
+#include <xen/events.h>
+
+#include "xen-ops.h"
+#include "debugfs.h"
+
+#ifdef CONFIG_XEN_DEBUG_FS
+static struct xen_spinlock_stats
+{
+	u64 taken;
+	u32 taken_slow;
+	u32 taken_slow_nested;
+	u32 taken_slow_pickup;
+	u32 taken_slow_spurious;
+	u32 taken_slow_irqenable;
+
+	u64 released;
+	u32 released_slow;
+	u32 released_slow_kicked;
+
+#define HISTO_BUCKETS	30
+	u32 histo_spin_total[HISTO_BUCKETS+1];
+	u32 histo_spin_spinning[HISTO_BUCKETS+1];
+	u32 histo_spin_blocked[HISTO_BUCKETS+1];
+
+	u64 time_total;
+	u64 time_spinning;
+	u64 time_blocked;
+} spinlock_stats;
+
+static u8 zero_stats;
+
+static unsigned lock_timeout = 1 << 10;
+#define TIMEOUT lock_timeout
+
+static inline void check_zero(void)
+{
+	if (unlikely(zero_stats)) {
+		memset(&spinlock_stats, 0, sizeof(spinlock_stats));
+		zero_stats = 0;
+	}
+}
+
+#define ADD_STATS(elem, val)			\
+	do { check_zero(); spinlock_stats.elem += (val); } while(0)
+
+static inline u64 spin_time_start(void)
+{
+	return xen_clocksource_read();
+}
+
+static void __spin_time_accum(u64 delta, u32 *array)
+{
+	unsigned index = ilog2(delta);
+
+	check_zero();
+
+	if (index < HISTO_BUCKETS)
+		array[index]++;
+	else
+		array[HISTO_BUCKETS]++;
+}
+
+static inline void spin_time_accum_spinning(u64 start)
+{
+	u32 delta = xen_clocksource_read() - start;
+
+	__spin_time_accum(delta, spinlock_stats.histo_spin_spinning);
+	spinlock_stats.time_spinning += delta;
+}
+
+static inline void spin_time_accum_total(u64 start)
+{
+	u32 delta = xen_clocksource_read() - start;
+
+	__spin_time_accum(delta, spinlock_stats.histo_spin_total);
+	spinlock_stats.time_total += delta;
+}
+
+static inline void spin_time_accum_blocked(u64 start)
+{
+	u32 delta = xen_clocksource_read() - start;
+
+	__spin_time_accum(delta, spinlock_stats.histo_spin_blocked);
+	spinlock_stats.time_blocked += delta;
+}
+#else  /* !CONFIG_XEN_DEBUG_FS */
+#define TIMEOUT			(1 << 10)
+#define ADD_STATS(elem, val)	do { (void)(val); } while(0)
+
+static inline u64 spin_time_start(void)
+{
+	return 0;
+}
+
+static inline void spin_time_accum_total(u64 start)
+{
+}
+static inline void spin_time_accum_spinning(u64 start)
+{
+}
+static inline void spin_time_accum_blocked(u64 start)
+{
+}
+#endif  /* CONFIG_XEN_DEBUG_FS */
+
+/*
+ * Size struct xen_spinlock so it's the same as arch_spinlock_t.
+ */
+#if NR_CPUS < 256
+typedef u8 xen_spinners_t;
+# define inc_spinners(xl) \
+	asm(LOCK_PREFIX " incb %0" : "+m" ((xl)->spinners) : : "memory");
+# define dec_spinners(xl) \
+	asm(LOCK_PREFIX " decb %0" : "+m" ((xl)->spinners) : : "memory");
+#else
+typedef u16 xen_spinners_t;
+# define inc_spinners(xl) \
+	asm(LOCK_PREFIX " incw %0" : "+m" ((xl)->spinners) : : "memory");
+# define dec_spinners(xl) \
+	asm(LOCK_PREFIX " decw %0" : "+m" ((xl)->spinners) : : "memory");
+#endif
+
+struct xen_spinlock {
+	unsigned char lock;		/* 0 -> free; 1 -> locked */
+	xen_spinners_t spinners;	/* count of waiting cpus */
+};
+
+static int xen_spin_is_locked(struct arch_spinlock *lock)
+{
+	struct xen_spinlock *xl = (struct xen_spinlock *)lock;
+
+	return xl->lock != 0;
+}
+
+static int xen_spin_is_contended(struct arch_spinlock *lock)
+{
+	struct xen_spinlock *xl = (struct xen_spinlock *)lock;
+
+	/* Not strictly true; this is only the count of contended
+	   lock-takers entering the slow path. */
+	return xl->spinners != 0;
+}
+
+static int xen_spin_trylock(struct arch_spinlock *lock)
+{
+	struct xen_spinlock *xl = (struct xen_spinlock *)lock;
+	u8 old = 1;
+
+	asm("xchgb %b0,%1"
+	    : "+q" (old), "+m" (xl->lock) : : "memory");
+
+	return old == 0;
+}
+
+static DEFINE_PER_CPU(int, lock_kicker_irq) = -1;
+static DEFINE_PER_CPU(struct xen_spinlock *, lock_spinners);
+
+/*
+ * Mark a cpu as interested in a lock.  Returns the CPU's previous
+ * lock of interest, in case we got preempted by an interrupt.
+ */
+static inline struct xen_spinlock *spinning_lock(struct xen_spinlock *xl)
+{
+	struct xen_spinlock *prev;
+
+	prev = __this_cpu_read(lock_spinners);
+	__this_cpu_write(lock_spinners, xl);
+
+	wmb();			/* set lock of interest before count */
+
+	inc_spinners(xl);
+
+	return prev;
+}
+
+/*
+ * Mark a cpu as no longer interested in a lock.  Restores previous
+ * lock of interest (NULL for none).
+ */
+static inline void unspinning_lock(struct xen_spinlock *xl, struct xen_spinlock *prev)
+{
+	dec_spinners(xl);
+	wmb();			/* decrement count before restoring lock */
+	__this_cpu_write(lock_spinners, prev);
+}
+
+static noinline int xen_spin_lock_slow(struct arch_spinlock *lock, bool irq_enable)
+{
+	struct xen_spinlock *xl = (struct xen_spinlock *)lock;
+	struct xen_spinlock *prev;
+	int irq = __this_cpu_read(lock_kicker_irq);
+	int ret;
+	u64 start;
+
+	/* If kicker interrupts not initialized yet, just spin */
+	if (irq == -1)
+		return 0;
+
+	start = spin_time_start();
+
+	/* announce we're spinning */
+	prev = spinning_lock(xl);
+
+	ADD_STATS(taken_slow, 1);
+	ADD_STATS(taken_slow_nested, prev != NULL);
+
+	do {
+		unsigned long flags;
+
+		/* clear pending */
+		xen_clear_irq_pending(irq);
+
+		/* check again make sure it didn't become free while
+		   we weren't looking  */
+		ret = xen_spin_trylock(lock);
+		if (ret) {
+			ADD_STATS(taken_slow_pickup, 1);
+
+			/*
+			 * If we interrupted another spinlock while it
+			 * was blocking, make sure it doesn't block
+			 * without rechecking the lock.
+			 */
+			if (prev != NULL)
+				xen_set_irq_pending(irq);
+			goto out;
+		}
+
+		flags = arch_local_save_flags();
+		if (irq_enable) {
+			ADD_STATS(taken_slow_irqenable, 1);
+			raw_local_irq_enable();
+		}
+
+		/*
+		 * Block until irq becomes pending.  If we're
+		 * interrupted at this point (after the trylock but
+		 * before entering the block), then the nested lock
+		 * handler guarantees that the irq will be left
+		 * pending if there's any chance the lock became free;
+		 * xen_poll_irq() returns immediately if the irq is
+		 * pending.
+		 */
+		xen_poll_irq(irq);
+
+		raw_local_irq_restore(flags);
+
+		ADD_STATS(taken_slow_spurious, !xen_test_irq_pending(irq));
+	} while (!xen_test_irq_pending(irq)); /* check for spurious wakeups */
+
+	kstat_incr_irqs_this_cpu(irq, irq_to_desc(irq));
+
+out:
+	unspinning_lock(xl, prev);
+	spin_time_accum_blocked(start);
+
+	return ret;
+}
+
+static inline void __xen_spin_lock(struct arch_spinlock *lock, bool irq_enable)
+{
+	struct xen_spinlock *xl = (struct xen_spinlock *)lock;
+	unsigned timeout;
+	u8 oldval;
+	u64 start_spin;
+
+	ADD_STATS(taken, 1);
+
+	start_spin = spin_time_start();
+
+	do {
+		u64 start_spin_fast = spin_time_start();
+
+		timeout = TIMEOUT;
+
+		asm("1: xchgb %1,%0\n"
+		    "   testb %1,%1\n"
+		    "   jz 3f\n"
+		    "2: rep;nop\n"
+		    "   cmpb $0,%0\n"
+		    "   je 1b\n"
+		    "   dec %2\n"
+		    "   jnz 2b\n"
+		    "3:\n"
+		    : "+m" (xl->lock), "=q" (oldval), "+r" (timeout)
+		    : "1" (1)
+		    : "memory");
+
+		spin_time_accum_spinning(start_spin_fast);
+
+	} while (unlikely(oldval != 0 &&
+			  (TIMEOUT == ~0 || !xen_spin_lock_slow(lock, irq_enable))));
+
+	spin_time_accum_total(start_spin);
+}
+
+static void xen_spin_lock(struct arch_spinlock *lock)
+{
+	__xen_spin_lock(lock, false);
+}
+
+static void xen_spin_lock_flags(struct arch_spinlock *lock, unsigned long flags)
+{
+	__xen_spin_lock(lock, !raw_irqs_disabled_flags(flags));
+}
+
+static noinline void xen_spin_unlock_slow(struct xen_spinlock *xl)
+{
+	int cpu;
+
+	ADD_STATS(released_slow, 1);
+
+	for_each_online_cpu(cpu) {
+		/* XXX should mix up next cpu selection */
+		if (per_cpu(lock_spinners, cpu) == xl) {
+			ADD_STATS(released_slow_kicked, 1);
+			xen_send_IPI_one(cpu, XEN_SPIN_UNLOCK_VECTOR);
+			break;
+		}
+	}
+}
+
+static void xen_spin_unlock(struct arch_spinlock *lock)
+{
+	struct xen_spinlock *xl = (struct xen_spinlock *)lock;
+
+	ADD_STATS(released, 1);
+
+	smp_wmb();		/* make sure no writes get moved after unlock */
+	xl->lock = 0;		/* release lock */
+
+	/*
+	 * Make sure unlock happens before checking for waiting
+	 * spinners.  We need a strong barrier to enforce the
+	 * write-read ordering to different memory locations, as the
+	 * CPU makes no implied guarantees about their ordering.
+	 */
+	mb();
+
+	if (unlikely(xl->spinners))
+		xen_spin_unlock_slow(xl);
+}
+
+static irqreturn_t dummy_handler(int irq, void *dev_id)
+{
+	BUG();
+	return IRQ_HANDLED;
+}
+
+void __cpuinit xen_init_lock_cpu(int cpu)
+{
+	int irq;
+	const char *name;
+
+	name = kasprintf(GFP_KERNEL, "spinlock%d", cpu);
+	irq = bind_ipi_to_irqhandler(XEN_SPIN_UNLOCK_VECTOR,
+				     cpu,
+				     dummy_handler,
+				     IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
+				     name,
+				     NULL);
+
+	if (irq >= 0) {
+		disable_irq(irq); /* make sure it's never delivered */
+		per_cpu(lock_kicker_irq, cpu) = irq;
+	}
+
+	printk("cpu %d spinlock event irq %d\n", cpu, irq);
+}
+
+void xen_uninit_lock_cpu(int cpu)
+{
+	unbind_from_irqhandler(per_cpu(lock_kicker_irq, cpu), NULL);
+}
+
+void __init xen_init_spinlocks(void)
+{
+	BUILD_BUG_ON(sizeof(struct xen_spinlock) > sizeof(arch_spinlock_t));
+
+	pv_lock_ops.spin_is_locked = xen_spin_is_locked;
+	pv_lock_ops.spin_is_contended = xen_spin_is_contended;
+	pv_lock_ops.spin_lock = xen_spin_lock;
+	pv_lock_ops.spin_lock_flags = xen_spin_lock_flags;
+	pv_lock_ops.spin_trylock = xen_spin_trylock;
+	pv_lock_ops.spin_unlock = xen_spin_unlock;
+}
+
+#ifdef CONFIG_XEN_DEBUG_FS
+
+static struct dentry *d_spin_debug;
+
+static int __init xen_spinlock_debugfs(void)
+{
+	struct dentry *d_xen = xen_init_debugfs();
+
+	if (d_xen == NULL)
+		return -ENOMEM;
+
+	d_spin_debug = debugfs_create_dir("spinlocks", d_xen);
+
+	debugfs_create_u8("zero_stats", 0644, d_spin_debug, &zero_stats);
+
+	debugfs_create_u32("timeout", 0644, d_spin_debug, &lock_timeout);
+
+	debugfs_create_u64("taken", 0444, d_spin_debug, &spinlock_stats.taken);
+	debugfs_create_u32("taken_slow", 0444, d_spin_debug,
+			   &spinlock_stats.taken_slow);
+	debugfs_create_u32("taken_slow_nested", 0444, d_spin_debug,
+			   &spinlock_stats.taken_slow_nested);
+	debugfs_create_u32("taken_slow_pickup", 0444, d_spin_debug,
+			   &spinlock_stats.taken_slow_pickup);
+	debugfs_create_u32("taken_slow_spurious", 0444, d_spin_debug,
+			   &spinlock_stats.taken_slow_spurious);
+	debugfs_create_u32("taken_slow_irqenable", 0444, d_spin_debug,
+			   &spinlock_stats.taken_slow_irqenable);
+
+	debugfs_create_u64("released", 0444, d_spin_debug, &spinlock_stats.released);
+	debugfs_create_u32("released_slow", 0444, d_spin_debug,
+			   &spinlock_stats.released_slow);
+	debugfs_create_u32("released_slow_kicked", 0444, d_spin_debug,
+			   &spinlock_stats.released_slow_kicked);
+
+	debugfs_create_u64("time_spinning", 0444, d_spin_debug,
+			   &spinlock_stats.time_spinning);
+	debugfs_create_u64("time_blocked", 0444, d_spin_debug,
+			   &spinlock_stats.time_blocked);
+	debugfs_create_u64("time_total", 0444, d_spin_debug,
+			   &spinlock_stats.time_total);
+
+	xen_debugfs_create_u32_array("histo_total", 0444, d_spin_debug,
+				     spinlock_stats.histo_spin_total, HISTO_BUCKETS + 1);
+	xen_debugfs_create_u32_array("histo_spinning", 0444, d_spin_debug,
+				     spinlock_stats.histo_spin_spinning, HISTO_BUCKETS + 1);
+	xen_debugfs_create_u32_array("histo_blocked", 0444, d_spin_debug,
+				     spinlock_stats.histo_spin_blocked, HISTO_BUCKETS + 1);
+
+	return 0;
+}
+fs_initcall(xen_spinlock_debugfs);
+
+#endif	/* CONFIG_XEN_DEBUG_FS */
diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c
new file mode 100644
index 00000000..45329c8c
--- /dev/null
+++ b/arch/x86/xen/suspend.c
@@ -0,0 +1,80 @@
+#include <linux/types.h>
+#include <linux/clockchips.h>
+
+#include <xen/interface/xen.h>
+#include <xen/grant_table.h>
+#include <xen/events.h>
+
+#include <asm/xen/hypercall.h>
+#include <asm/xen/page.h>
+#include <asm/fixmap.h>
+
+#include "xen-ops.h"
+#include "mmu.h"
+
+void xen_arch_pre_suspend(void)
+{
+	xen_start_info->store_mfn = mfn_to_pfn(xen_start_info->store_mfn);
+	xen_start_info->console.domU.mfn =
+		mfn_to_pfn(xen_start_info->console.domU.mfn);
+
+	BUG_ON(!irqs_disabled());
+
+	HYPERVISOR_shared_info = &xen_dummy_shared_info;
+	if (HYPERVISOR_update_va_mapping(fix_to_virt(FIX_PARAVIRT_BOOTMAP),
+					 __pte_ma(0), 0))
+		BUG();
+}
+
+void xen_arch_hvm_post_suspend(int suspend_cancelled)
+{
+#ifdef CONFIG_XEN_PVHVM
+	int cpu;
+	xen_hvm_init_shared_info();
+	xen_callback_vector();
+	xen_unplug_emulated_devices();
+	if (xen_feature(XENFEAT_hvm_safe_pvclock)) {
+		for_each_online_cpu(cpu) {
+			xen_setup_runstate_info(cpu);
+		}
+	}
+#endif
+}
+
+void xen_arch_post_suspend(int suspend_cancelled)
+{
+	xen_build_mfn_list_list();
+
+	xen_setup_shared_info();
+
+	if (suspend_cancelled) {
+		xen_start_info->store_mfn =
+			pfn_to_mfn(xen_start_info->store_mfn);
+		xen_start_info->console.domU.mfn =
+			pfn_to_mfn(xen_start_info->console.domU.mfn);
+	} else {
+#ifdef CONFIG_SMP
+		BUG_ON(xen_cpu_initialized_map == NULL);
+		cpumask_copy(xen_cpu_initialized_map, cpu_online_mask);
+#endif
+		xen_vcpu_restore();
+	}
+
+}
+
+static void xen_vcpu_notify_restore(void *data)
+{
+	unsigned long reason = (unsigned long)data;
+
+	/* Boot processor notified via generic timekeeping_resume() */
+	if ( smp_processor_id() == 0)
+		return;
+
+	clockevents_notify(reason, NULL);
+}
+
+void xen_arch_resume(void)
+{
+	on_each_cpu(xen_vcpu_notify_restore,
+		    (void *)CLOCK_EVT_NOTIFY_RESUME, 1);
+}
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
new file mode 100644
index 00000000..0296a952
--- /dev/null
+++ b/arch/x86/xen/time.c
@@ -0,0 +1,525 @@
+/*
+ * Xen time implementation.
+ *
+ * This is implemented in terms of a clocksource driver which uses
+ * the hypervisor clock as a nanosecond timebase, and a clockevent
+ * driver which uses the hypervisor's timer mechanism.
+ *
+ * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
+ */
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/kernel_stat.h>
+#include <linux/math64.h>
+#include <linux/gfp.h>
+
+#include <asm/pvclock.h>
+#include <asm/xen/hypervisor.h>
+#include <asm/xen/hypercall.h>
+
+#include <xen/events.h>
+#include <xen/features.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/vcpu.h>
+
+#include "xen-ops.h"
+
+/* Xen may fire a timer up to this many ns early */
+#define TIMER_SLOP	100000
+#define NS_PER_TICK	(1000000000LL / HZ)
+
+/* runstate info updated by Xen */
+static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate);
+
+/* snapshots of runstate info */
+static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate_snapshot);
+
+/* unused ns of stolen and blocked time */
+static DEFINE_PER_CPU(u64, xen_residual_stolen);
+static DEFINE_PER_CPU(u64, xen_residual_blocked);
+
+/* return an consistent snapshot of 64-bit time/counter value */
+static u64 get64(const u64 *p)
+{
+	u64 ret;
+
+	if (BITS_PER_LONG < 64) {
+		u32 *p32 = (u32 *)p;
+		u32 h, l;
+
+		/*
+		 * Read high then low, and then make sure high is
+		 * still the same; this will only loop if low wraps
+		 * and carries into high.
+		 * XXX some clean way to make this endian-proof?
+		 */
+		do {
+			h = p32[1];
+			barrier();
+			l = p32[0];
+			barrier();
+		} while (p32[1] != h);
+
+		ret = (((u64)h) << 32) | l;
+	} else
+		ret = *p;
+
+	return ret;
+}
+
+/*
+ * Runstate accounting
+ */
+static void get_runstate_snapshot(struct vcpu_runstate_info *res)
+{
+	u64 state_time;
+	struct vcpu_runstate_info *state;
+
+	BUG_ON(preemptible());
+
+	state = &__get_cpu_var(xen_runstate);
+
+	/*
+	 * The runstate info is always updated by the hypervisor on
+	 * the current CPU, so there's no need to use anything
+	 * stronger than a compiler barrier when fetching it.
+	 */
+	do {
+		state_time = get64(&state->state_entry_time);
+		barrier();
+		*res = *state;
+		barrier();
+	} while (get64(&state->state_entry_time) != state_time);
+}
+
+/* return true when a vcpu could run but has no real cpu to run on */
+bool xen_vcpu_stolen(int vcpu)
+{
+	return per_cpu(xen_runstate, vcpu).state == RUNSTATE_runnable;
+}
+
+void xen_setup_runstate_info(int cpu)
+{
+	struct vcpu_register_runstate_memory_area area;
+
+	area.addr.v = &per_cpu(xen_runstate, cpu);
+
+	if (HYPERVISOR_vcpu_op(VCPUOP_register_runstate_memory_area,
+			       cpu, &area))
+		BUG();
+}
+
+static void do_stolen_accounting(void)
+{
+	struct vcpu_runstate_info state;
+	struct vcpu_runstate_info *snap;
+	s64 blocked, runnable, offline, stolen;
+	cputime_t ticks;
+
+	get_runstate_snapshot(&state);
+
+	WARN_ON(state.state != RUNSTATE_running);
+
+	snap = &__get_cpu_var(xen_runstate_snapshot);
+
+	/* work out how much time the VCPU has not been runn*ing*  */
+	blocked = state.time[RUNSTATE_blocked] - snap->time[RUNSTATE_blocked];
+	runnable = state.time[RUNSTATE_runnable] - snap->time[RUNSTATE_runnable];
+	offline = state.time[RUNSTATE_offline] - snap->time[RUNSTATE_offline];
+
+	*snap = state;
+
+	/* Add the appropriate number of ticks of stolen time,
+	   including any left-overs from last time. */
+	stolen = runnable + offline + __this_cpu_read(xen_residual_stolen);
+
+	if (stolen < 0)
+		stolen = 0;
+
+	ticks = iter_div_u64_rem(stolen, NS_PER_TICK, &stolen);
+	__this_cpu_write(xen_residual_stolen, stolen);
+	account_steal_ticks(ticks);
+
+	/* Add the appropriate number of ticks of blocked time,
+	   including any left-overs from last time. */
+	blocked += __this_cpu_read(xen_residual_blocked);
+
+	if (blocked < 0)
+		blocked = 0;
+
+	ticks = iter_div_u64_rem(blocked, NS_PER_TICK, &blocked);
+	__this_cpu_write(xen_residual_blocked, blocked);
+	account_idle_ticks(ticks);
+}
+
+/* Get the TSC speed from Xen */
+static unsigned long xen_tsc_khz(void)
+{
+	struct pvclock_vcpu_time_info *info =
+		&HYPERVISOR_shared_info->vcpu_info[0].time;
+
+	return pvclock_tsc_khz(info);
+}
+
+cycle_t xen_clocksource_read(void)
+{
+        struct pvclock_vcpu_time_info *src;
+	cycle_t ret;
+
+	preempt_disable_notrace();
+	src = &__get_cpu_var(xen_vcpu)->time;
+	ret = pvclock_clocksource_read(src);
+	preempt_enable_notrace();
+	return ret;
+}
+
+static cycle_t xen_clocksource_get_cycles(struct clocksource *cs)
+{
+	return xen_clocksource_read();
+}
+
+static void xen_read_wallclock(struct timespec *ts)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	struct pvclock_wall_clock *wall_clock = &(s->wc);
+        struct pvclock_vcpu_time_info *vcpu_time;
+
+	vcpu_time = &get_cpu_var(xen_vcpu)->time;
+	pvclock_read_wallclock(wall_clock, vcpu_time, ts);
+	put_cpu_var(xen_vcpu);
+}
+
+static unsigned long xen_get_wallclock(void)
+{
+	struct timespec ts;
+
+	xen_read_wallclock(&ts);
+	return ts.tv_sec;
+}
+
+static int xen_set_wallclock(unsigned long now)
+{
+	struct xen_platform_op op;
+	int rc;
+
+	/* do nothing for domU */
+	if (!xen_initial_domain())
+		return -1;
+
+	op.cmd = XENPF_settime;
+	op.u.settime.secs = now;
+	op.u.settime.nsecs = 0;
+	op.u.settime.system_time = xen_clocksource_read();
+
+	rc = HYPERVISOR_dom0_op(&op);
+	WARN(rc != 0, "XENPF_settime failed: now=%ld\n", now);
+
+	return rc;
+}
+
+static struct clocksource xen_clocksource __read_mostly = {
+	.name = "xen",
+	.rating = 400,
+	.read = xen_clocksource_get_cycles,
+	.mask = ~0,
+	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+/*
+   Xen clockevent implementation
+
+   Xen has two clockevent implementations:
+
+   The old timer_op one works with all released versions of Xen prior
+   to version 3.0.4.  This version of the hypervisor provides a
+   single-shot timer with nanosecond resolution.  However, sharing the
+   same event channel is a 100Hz tick which is delivered while the
+   vcpu is running.  We don't care about or use this tick, but it will
+   cause the core time code to think the timer fired too soon, and
+   will end up resetting it each time.  It could be filtered, but
+   doing so has complications when the ktime clocksource is not yet
+   the xen clocksource (ie, at boot time).
+
+   The new vcpu_op-based timer interface allows the tick timer period
+   to be changed or turned off.  The tick timer is not useful as a
+   periodic timer because events are only delivered to running vcpus.
+   The one-shot timer can report when a timeout is in the past, so
+   set_next_event is capable of returning -ETIME when appropriate.
+   This interface is used when available.
+*/
+
+
+/*
+  Get a hypervisor absolute time.  In theory we could maintain an
+  offset between the kernel's time and the hypervisor's time, and
+  apply that to a kernel's absolute timeout.  Unfortunately the
+  hypervisor and kernel times can drift even if the kernel is using
+  the Xen clocksource, because ntp can warp the kernel's clocksource.
+*/
+static s64 get_abs_timeout(unsigned long delta)
+{
+	return xen_clocksource_read() + delta;
+}
+
+static void xen_timerop_set_mode(enum clock_event_mode mode,
+				 struct clock_event_device *evt)
+{
+	switch (mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		/* unsupported */
+		WARN_ON(1);
+		break;
+
+	case CLOCK_EVT_MODE_ONESHOT:
+	case CLOCK_EVT_MODE_RESUME:
+		break;
+
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+		HYPERVISOR_set_timer_op(0);  /* cancel timeout */
+		break;
+	}
+}
+
+static int xen_timerop_set_next_event(unsigned long delta,
+				      struct clock_event_device *evt)
+{
+	WARN_ON(evt->mode != CLOCK_EVT_MODE_ONESHOT);
+
+	if (HYPERVISOR_set_timer_op(get_abs_timeout(delta)) < 0)
+		BUG();
+
+	/* We may have missed the deadline, but there's no real way of
+	   knowing for sure.  If the event was in the past, then we'll
+	   get an immediate interrupt. */
+
+	return 0;
+}
+
+static const struct clock_event_device xen_timerop_clockevent = {
+	.name = "xen",
+	.features = CLOCK_EVT_FEAT_ONESHOT,
+
+	.max_delta_ns = 0xffffffff,
+	.min_delta_ns = TIMER_SLOP,
+
+	.mult = 1,
+	.shift = 0,
+	.rating = 500,
+
+	.set_mode = xen_timerop_set_mode,
+	.set_next_event = xen_timerop_set_next_event,
+};
+
+
+
+static void xen_vcpuop_set_mode(enum clock_event_mode mode,
+				struct clock_event_device *evt)
+{
+	int cpu = smp_processor_id();
+
+	switch (mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		WARN_ON(1);	/* unsupported */
+		break;
+
+	case CLOCK_EVT_MODE_ONESHOT:
+		if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL))
+			BUG();
+		break;
+
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+		if (HYPERVISOR_vcpu_op(VCPUOP_stop_singleshot_timer, cpu, NULL) ||
+		    HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL))
+			BUG();
+		break;
+	case CLOCK_EVT_MODE_RESUME:
+		break;
+	}
+}
+
+static int xen_vcpuop_set_next_event(unsigned long delta,
+				     struct clock_event_device *evt)
+{
+	int cpu = smp_processor_id();
+	struct vcpu_set_singleshot_timer single;
+	int ret;
+
+	WARN_ON(evt->mode != CLOCK_EVT_MODE_ONESHOT);
+
+	single.timeout_abs_ns = get_abs_timeout(delta);
+	single.flags = VCPU_SSHOTTMR_future;
+
+	ret = HYPERVISOR_vcpu_op(VCPUOP_set_singleshot_timer, cpu, &single);
+
+	BUG_ON(ret != 0 && ret != -ETIME);
+
+	return ret;
+}
+
+static const struct clock_event_device xen_vcpuop_clockevent = {
+	.name = "xen",
+	.features = CLOCK_EVT_FEAT_ONESHOT,
+
+	.max_delta_ns = 0xffffffff,
+	.min_delta_ns = TIMER_SLOP,
+
+	.mult = 1,
+	.shift = 0,
+	.rating = 500,
+
+	.set_mode = xen_vcpuop_set_mode,
+	.set_next_event = xen_vcpuop_set_next_event,
+};
+
+static const struct clock_event_device *xen_clockevent =
+	&xen_timerop_clockevent;
+static DEFINE_PER_CPU(struct clock_event_device, xen_clock_events);
+
+static irqreturn_t xen_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = &__get_cpu_var(xen_clock_events);
+	irqreturn_t ret;
+
+	ret = IRQ_NONE;
+	if (evt->event_handler) {
+		evt->event_handler(evt);
+		ret = IRQ_HANDLED;
+	}
+
+	do_stolen_accounting();
+
+	return ret;
+}
+
+void xen_setup_timer(int cpu)
+{
+	const char *name;
+	struct clock_event_device *evt;
+	int irq;
+
+	printk(KERN_INFO "installing Xen timer for CPU %d\n", cpu);
+
+	name = kasprintf(GFP_KERNEL, "timer%d", cpu);
+	if (!name)
+		name = "<timer kasprintf failed>";
+
+	irq = bind_virq_to_irqhandler(VIRQ_TIMER, cpu, xen_timer_interrupt,
+				      IRQF_DISABLED|IRQF_PERCPU|
+				      IRQF_NOBALANCING|IRQF_TIMER|
+				      IRQF_FORCE_RESUME,
+				      name, NULL);
+
+	evt = &per_cpu(xen_clock_events, cpu);
+	memcpy(evt, xen_clockevent, sizeof(*evt));
+
+	evt->cpumask = cpumask_of(cpu);
+	evt->irq = irq;
+}
+
+void xen_teardown_timer(int cpu)
+{
+	struct clock_event_device *evt;
+	BUG_ON(cpu == 0);
+	evt = &per_cpu(xen_clock_events, cpu);
+	unbind_from_irqhandler(evt->irq, NULL);
+}
+
+void xen_setup_cpu_clockevents(void)
+{
+	BUG_ON(preemptible());
+
+	clockevents_register_device(&__get_cpu_var(xen_clock_events));
+}
+
+void xen_timer_resume(void)
+{
+	int cpu;
+
+	pvclock_resume();
+
+	if (xen_clockevent != &xen_vcpuop_clockevent)
+		return;
+
+	for_each_online_cpu(cpu) {
+		if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL))
+			BUG();
+	}
+}
+
+static const struct pv_time_ops xen_time_ops __initconst = {
+	.sched_clock = xen_clocksource_read,
+};
+
+static void __init xen_time_init(void)
+{
+	int cpu = smp_processor_id();
+	struct timespec tp;
+
+	clocksource_register_hz(&xen_clocksource, NSEC_PER_SEC);
+
+	if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL) == 0) {
+		/* Successfully turned off 100Hz tick, so we have the
+		   vcpuop-based timer interface */
+		printk(KERN_DEBUG "Xen: using vcpuop timer interface\n");
+		xen_clockevent = &xen_vcpuop_clockevent;
+	}
+
+	/* Set initial system time with full resolution */
+	xen_read_wallclock(&tp);
+	do_settimeofday(&tp);
+
+	setup_force_cpu_cap(X86_FEATURE_TSC);
+
+	xen_setup_runstate_info(cpu);
+	xen_setup_timer(cpu);
+	xen_setup_cpu_clockevents();
+}
+
+void __init xen_init_time_ops(void)
+{
+	pv_time_ops = xen_time_ops;
+
+	x86_init.timers.timer_init = xen_time_init;
+	x86_init.timers.setup_percpu_clockev = x86_init_noop;
+	x86_cpuinit.setup_percpu_clockev = x86_init_noop;
+
+	x86_platform.calibrate_tsc = xen_tsc_khz;
+	x86_platform.get_wallclock = xen_get_wallclock;
+	x86_platform.set_wallclock = xen_set_wallclock;
+}
+
+#ifdef CONFIG_XEN_PVHVM
+static void xen_hvm_setup_cpu_clockevents(void)
+{
+	int cpu = smp_processor_id();
+	xen_setup_runstate_info(cpu);
+	xen_setup_timer(cpu);
+	xen_setup_cpu_clockevents();
+}
+
+void __init xen_hvm_init_time_ops(void)
+{
+	/* vector callback is needed otherwise we cannot receive interrupts
+	 * on cpu > 0 and at this point we don't know how many cpus are
+	 * available */
+	if (!xen_have_vector_callback)
+		return;
+	if (!xen_feature(XENFEAT_hvm_safe_pvclock)) {
+		printk(KERN_INFO "Xen doesn't support pvclock on HVM,"
+				"disable pv timer\n");
+		return;
+	}
+
+	pv_time_ops = xen_time_ops;
+	x86_init.timers.setup_percpu_clockev = xen_time_init;
+	x86_cpuinit.setup_percpu_clockev = xen_hvm_setup_cpu_clockevents;
+
+	x86_platform.calibrate_tsc = xen_tsc_khz;
+	x86_platform.get_wallclock = xen_get_wallclock;
+	x86_platform.set_wallclock = xen_set_wallclock;
+}
+#endif
diff --git a/arch/x86/xen/trace.c b/arch/x86/xen/trace.c
new file mode 100644
index 00000000..520022d1
--- /dev/null
+++ b/arch/x86/xen/trace.c
@@ -0,0 +1,62 @@
+#include <linux/ftrace.h>
+#include <xen/interface/xen.h>
+
+#define N(x)	[__HYPERVISOR_##x] = "("#x")"
+static const char *xen_hypercall_names[] = {
+	N(set_trap_table),
+	N(mmu_update),
+	N(set_gdt),
+	N(stack_switch),
+	N(set_callbacks),
+	N(fpu_taskswitch),
+	N(sched_op_compat),
+	N(dom0_op),
+	N(set_debugreg),
+	N(get_debugreg),
+	N(update_descriptor),
+	N(memory_op),
+	N(multicall),
+	N(update_va_mapping),
+	N(set_timer_op),
+	N(event_channel_op_compat),
+	N(xen_version),
+	N(console_io),
+	N(physdev_op_compat),
+	N(grant_table_op),
+	N(vm_assist),
+	N(update_va_mapping_otherdomain),
+	N(iret),
+	N(vcpu_op),
+	N(set_segment_base),
+	N(mmuext_op),
+	N(acm_op),
+	N(nmi_op),
+	N(sched_op),
+	N(callback_op),
+	N(xenoprof_op),
+	N(event_channel_op),
+	N(physdev_op),
+	N(hvm_op),
+
+/* Architecture-specific hypercall definitions. */
+	N(arch_0),
+	N(arch_1),
+	N(arch_2),
+	N(arch_3),
+	N(arch_4),
+	N(arch_5),
+	N(arch_6),
+	N(arch_7),
+};
+#undef N
+
+static const char *xen_hypercall_name(unsigned op)
+{
+	if (op < ARRAY_SIZE(xen_hypercall_names) && xen_hypercall_names[op] != NULL)
+		return xen_hypercall_names[op];
+
+	return "";
+}
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/xen.h>
diff --git a/arch/x86/xen/vdso.h b/arch/x86/xen/vdso.h
new file mode 100644
index 00000000..861fedfe
--- /dev/null
+++ b/arch/x86/xen/vdso.h
@@ -0,0 +1,4 @@
+/* Bit used for the pseudo-hwcap for non-negative segments.  We use
+   bit 1 to avoid bugs in some versions of glibc when bit 0 is
+   used; the choice is otherwise arbitrary. */
+#define VDSO_NOTE_NONEGSEG_BIT	1
diff --git a/arch/x86/xen/vga.c b/arch/x86/xen/vga.c
new file mode 100644
index 00000000..1cd7f4d1
--- /dev/null
+++ b/arch/x86/xen/vga.c
@@ -0,0 +1,67 @@
+#include <linux/screen_info.h>
+#include <linux/init.h>
+
+#include <asm/bootparam.h>
+#include <asm/setup.h>
+
+#include <xen/interface/xen.h>
+
+#include "xen-ops.h"
+
+void __init xen_init_vga(const struct dom0_vga_console_info *info, size_t size)
+{
+	struct screen_info *screen_info = &boot_params.screen_info;
+
+	/* This is drawn from a dump from vgacon:startup in
+	 * standard Linux. */
+	screen_info->orig_video_mode = 3;
+	screen_info->orig_video_isVGA = 1;
+	screen_info->orig_video_lines = 25;
+	screen_info->orig_video_cols = 80;
+	screen_info->orig_video_ega_bx = 3;
+	screen_info->orig_video_points = 16;
+	screen_info->orig_y = screen_info->orig_video_lines - 1;
+
+	switch (info->video_type) {
+	case XEN_VGATYPE_TEXT_MODE_3:
+		if (size < offsetof(struct dom0_vga_console_info, u.text_mode_3)
+		    + sizeof(info->u.text_mode_3))
+			break;
+		screen_info->orig_video_lines = info->u.text_mode_3.rows;
+		screen_info->orig_video_cols = info->u.text_mode_3.columns;
+		screen_info->orig_x = info->u.text_mode_3.cursor_x;
+		screen_info->orig_y = info->u.text_mode_3.cursor_y;
+		screen_info->orig_video_points =
+			info->u.text_mode_3.font_height;
+		break;
+
+	case XEN_VGATYPE_VESA_LFB:
+		if (size < offsetof(struct dom0_vga_console_info,
+				    u.vesa_lfb.gbl_caps))
+			break;
+		screen_info->orig_video_isVGA = VIDEO_TYPE_VLFB;
+		screen_info->lfb_width = info->u.vesa_lfb.width;
+		screen_info->lfb_height = info->u.vesa_lfb.height;
+		screen_info->lfb_depth = info->u.vesa_lfb.bits_per_pixel;
+		screen_info->lfb_base = info->u.vesa_lfb.lfb_base;
+		screen_info->lfb_size = info->u.vesa_lfb.lfb_size;
+		screen_info->lfb_linelength = info->u.vesa_lfb.bytes_per_line;
+		screen_info->red_size = info->u.vesa_lfb.red_size;
+		screen_info->red_pos = info->u.vesa_lfb.red_pos;
+		screen_info->green_size = info->u.vesa_lfb.green_size;
+		screen_info->green_pos = info->u.vesa_lfb.green_pos;
+		screen_info->blue_size = info->u.vesa_lfb.blue_size;
+		screen_info->blue_pos = info->u.vesa_lfb.blue_pos;
+		screen_info->rsvd_size = info->u.vesa_lfb.rsvd_size;
+		screen_info->rsvd_pos = info->u.vesa_lfb.rsvd_pos;
+		if (size >= offsetof(struct dom0_vga_console_info,
+				     u.vesa_lfb.gbl_caps)
+		    + sizeof(info->u.vesa_lfb.gbl_caps))
+			screen_info->capabilities = info->u.vesa_lfb.gbl_caps;
+		if (size >= offsetof(struct dom0_vga_console_info,
+				     u.vesa_lfb.mode_attrs)
+		    + sizeof(info->u.vesa_lfb.mode_attrs))
+			screen_info->vesa_attributes = info->u.vesa_lfb.mode_attrs;
+		break;
+	}
+}
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S
new file mode 100644
index 00000000..3e45aa00
--- /dev/null
+++ b/arch/x86/xen/xen-asm.S
@@ -0,0 +1,142 @@
+/*
+ * Asm versions of Xen pv-ops, suitable for either direct use or
+ * inlining.  The inline versions are the same as the direct-use
+ * versions, with the pre- and post-amble chopped off.
+ *
+ * This code is encoded for size rather than absolute efficiency, with
+ * a view to being able to inline as much as possible.
+ *
+ * We only bother with direct forms (ie, vcpu in percpu data) of the
+ * operations here; the indirect forms are better handled in C, since
+ * they're generally too large to inline anyway.
+ */
+
+#include <asm/asm-offsets.h>
+#include <asm/percpu.h>
+#include <asm/processor-flags.h>
+
+#include "xen-asm.h"
+
+/*
+ * Enable events.  This clears the event mask and tests the pending
+ * event status with one and operation.  If there are pending events,
+ * then enter the hypervisor to get them handled.
+ */
+ENTRY(xen_irq_enable_direct)
+	/* Unmask events */
+	movb $0, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
+
+	/*
+	 * Preempt here doesn't matter because that will deal with any
+	 * pending interrupts.  The pending check may end up being run
+	 * on the wrong CPU, but that doesn't hurt.
+	 */
+
+	/* Test for pending */
+	testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_pending
+	jz 1f
+
+2:	call check_events
+1:
+ENDPATCH(xen_irq_enable_direct)
+	ret
+	ENDPROC(xen_irq_enable_direct)
+	RELOC(xen_irq_enable_direct, 2b+1)
+
+
+/*
+ * Disabling events is simply a matter of making the event mask
+ * non-zero.
+ */
+ENTRY(xen_irq_disable_direct)
+	movb $1, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
+ENDPATCH(xen_irq_disable_direct)
+	ret
+	ENDPROC(xen_irq_disable_direct)
+	RELOC(xen_irq_disable_direct, 0)
+
+/*
+ * (xen_)save_fl is used to get the current interrupt enable status.
+ * Callers expect the status to be in X86_EFLAGS_IF, and other bits
+ * may be set in the return value.  We take advantage of this by
+ * making sure that X86_EFLAGS_IF has the right value (and other bits
+ * in that byte are 0), but other bits in the return value are
+ * undefined.  We need to toggle the state of the bit, because Xen and
+ * x86 use opposite senses (mask vs enable).
+ */
+ENTRY(xen_save_fl_direct)
+	testb $0xff, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
+	setz %ah
+	addb %ah, %ah
+ENDPATCH(xen_save_fl_direct)
+	ret
+	ENDPROC(xen_save_fl_direct)
+	RELOC(xen_save_fl_direct, 0)
+
+
+/*
+ * In principle the caller should be passing us a value return from
+ * xen_save_fl_direct, but for robustness sake we test only the
+ * X86_EFLAGS_IF flag rather than the whole byte. After setting the
+ * interrupt mask state, it checks for unmasked pending events and
+ * enters the hypervisor to get them delivered if so.
+ */
+ENTRY(xen_restore_fl_direct)
+#ifdef CONFIG_X86_64
+	testw $X86_EFLAGS_IF, %di
+#else
+	testb $X86_EFLAGS_IF>>8, %ah
+#endif
+	setz PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_mask
+	/*
+	 * Preempt here doesn't matter because that will deal with any
+	 * pending interrupts.  The pending check may end up being run
+	 * on the wrong CPU, but that doesn't hurt.
+	 */
+
+	/* check for unmasked and pending */
+	cmpw $0x0001, PER_CPU_VAR(xen_vcpu_info) + XEN_vcpu_info_pending
+	jnz 1f
+2:	call check_events
+1:
+ENDPATCH(xen_restore_fl_direct)
+	ret
+	ENDPROC(xen_restore_fl_direct)
+	RELOC(xen_restore_fl_direct, 2b+1)
+
+
+/*
+ * Force an event check by making a hypercall, but preserve regs
+ * before making the call.
+ */
+check_events:
+#ifdef CONFIG_X86_32
+	push %eax
+	push %ecx
+	push %edx
+	call xen_force_evtchn_callback
+	pop %edx
+	pop %ecx
+	pop %eax
+#else
+	push %rax
+	push %rcx
+	push %rdx
+	push %rsi
+	push %rdi
+	push %r8
+	push %r9
+	push %r10
+	push %r11
+	call xen_force_evtchn_callback
+	pop %r11
+	pop %r10
+	pop %r9
+	pop %r8
+	pop %rdi
+	pop %rsi
+	pop %rdx
+	pop %rcx
+	pop %rax
+#endif
+	ret
diff --git a/arch/x86/xen/xen-asm.h b/arch/x86/xen/xen-asm.h
new file mode 100644
index 00000000..46527646
--- /dev/null
+++ b/arch/x86/xen/xen-asm.h
@@ -0,0 +1,12 @@
+#ifndef _XEN_XEN_ASM_H
+#define _XEN_XEN_ASM_H
+
+#include <linux/linkage.h>
+
+#define RELOC(x, v)	.globl x##_reloc; x##_reloc=v
+#define ENDPATCH(x)	.globl x##_end; x##_end=.
+
+/* Pseudo-flag used for virtual NMI, which we don't implement yet */
+#define XEN_EFLAGS_NMI	0x80000000
+
+#endif
diff --git a/arch/x86/xen/xen-asm_32.S b/arch/x86/xen/xen-asm_32.S
new file mode 100644
index 00000000..b040b0e5
--- /dev/null
+++ b/arch/x86/xen/xen-asm_32.S
@@ -0,0 +1,230 @@
+/*
+ * Asm versions of Xen pv-ops, suitable for either direct use or
+ * inlining.  The inline versions are the same as the direct-use
+ * versions, with the pre- and post-amble chopped off.
+ *
+ * This code is encoded for size rather than absolute efficiency, with
+ * a view to being able to inline as much as possible.
+ *
+ * We only bother with direct forms (ie, vcpu in pda) of the
+ * operations here; the indirect forms are better handled in C, since
+ * they're generally too large to inline anyway.
+ */
+
+#include <asm/thread_info.h>
+#include <asm/processor-flags.h>
+#include <asm/segment.h>
+
+#include <xen/interface/xen.h>
+
+#include "xen-asm.h"
+
+/*
+ * Force an event check by making a hypercall, but preserve regs
+ * before making the call.
+ */
+check_events:
+	push %eax
+	push %ecx
+	push %edx
+	call xen_force_evtchn_callback
+	pop %edx
+	pop %ecx
+	pop %eax
+	ret
+
+/*
+ * We can't use sysexit directly, because we're not running in ring0.
+ * But we can easily fake it up using iret.  Assuming xen_sysexit is
+ * jumped to with a standard stack frame, we can just strip it back to
+ * a standard iret frame and use iret.
+ */
+ENTRY(xen_sysexit)
+	movl PT_EAX(%esp), %eax			/* Shouldn't be necessary? */
+	orl $X86_EFLAGS_IF, PT_EFLAGS(%esp)
+	lea PT_EIP(%esp), %esp
+
+	jmp xen_iret
+ENDPROC(xen_sysexit)
+
+/*
+ * This is run where a normal iret would be run, with the same stack setup:
+ *	8: eflags
+ *	4: cs
+ *	esp-> 0: eip
+ *
+ * This attempts to make sure that any pending events are dealt with
+ * on return to usermode, but there is a small window in which an
+ * event can happen just before entering usermode.  If the nested
+ * interrupt ends up setting one of the TIF_WORK_MASK pending work
+ * flags, they will not be tested again before returning to
+ * usermode. This means that a process can end up with pending work,
+ * which will be unprocessed until the process enters and leaves the
+ * kernel again, which could be an unbounded amount of time.  This
+ * means that a pending signal or reschedule event could be
+ * indefinitely delayed.
+ *
+ * The fix is to notice a nested interrupt in the critical window, and
+ * if one occurs, then fold the nested interrupt into the current
+ * interrupt stack frame, and re-process it iteratively rather than
+ * recursively.  This means that it will exit via the normal path, and
+ * all pending work will be dealt with appropriately.
+ *
+ * Because the nested interrupt handler needs to deal with the current
+ * stack state in whatever form its in, we keep things simple by only
+ * using a single register which is pushed/popped on the stack.
+ */
+ENTRY(xen_iret)
+	/* test eflags for special cases */
+	testl $(X86_EFLAGS_VM | XEN_EFLAGS_NMI), 8(%esp)
+	jnz hyper_iret
+
+	push %eax
+	ESP_OFFSET=4	# bytes pushed onto stack
+
+	/*
+	 * Store vcpu_info pointer for easy access.  Do it this way to
+	 * avoid having to reload %fs
+	 */
+#ifdef CONFIG_SMP
+	GET_THREAD_INFO(%eax)
+	movl TI_cpu(%eax), %eax
+	movl __per_cpu_offset(,%eax,4), %eax
+	mov xen_vcpu(%eax), %eax
+#else
+	movl xen_vcpu, %eax
+#endif
+
+	/* check IF state we're restoring */
+	testb $X86_EFLAGS_IF>>8, 8+1+ESP_OFFSET(%esp)
+
+	/*
+	 * Maybe enable events.  Once this happens we could get a
+	 * recursive event, so the critical region starts immediately
+	 * afterwards.  However, if that happens we don't end up
+	 * resuming the code, so we don't have to be worried about
+	 * being preempted to another CPU.
+	 */
+	setz XEN_vcpu_info_mask(%eax)
+xen_iret_start_crit:
+
+	/* check for unmasked and pending */
+	cmpw $0x0001, XEN_vcpu_info_pending(%eax)
+
+	/*
+	 * If there's something pending, mask events again so we can
+	 * jump back into xen_hypervisor_callback. Otherwise do not
+	 * touch XEN_vcpu_info_mask.
+	 */
+	jne 1f
+	movb $1, XEN_vcpu_info_mask(%eax)
+
+1:	popl %eax
+
+	/*
+	 * From this point on the registers are restored and the stack
+	 * updated, so we don't need to worry about it if we're
+	 * preempted
+	 */
+iret_restore_end:
+
+	/*
+	 * Jump to hypervisor_callback after fixing up the stack.
+	 * Events are masked, so jumping out of the critical region is
+	 * OK.
+	 */
+	je xen_hypervisor_callback
+
+1:	iret
+xen_iret_end_crit:
+.section __ex_table, "a"
+	.align 4
+	.long 1b, iret_exc
+.previous
+
+hyper_iret:
+	/* put this out of line since its very rarely used */
+	jmp hypercall_page + __HYPERVISOR_iret * 32
+
+	.globl xen_iret_start_crit, xen_iret_end_crit
+
+/*
+ * This is called by xen_hypervisor_callback in entry.S when it sees
+ * that the EIP at the time of interrupt was between
+ * xen_iret_start_crit and xen_iret_end_crit.  We're passed the EIP in
+ * %eax so we can do a more refined determination of what to do.
+ *
+ * The stack format at this point is:
+ *	----------------
+ *	 ss		: (ss/esp may be present if we came from usermode)
+ *	 esp		:
+ *	 eflags		}  outer exception info
+ *	 cs		}
+ *	 eip		}
+ *	---------------- <- edi (copy dest)
+ *	 eax		:  outer eax if it hasn't been restored
+ *	----------------
+ *	 eflags		}  nested exception info
+ *	 cs		}   (no ss/esp because we're nested
+ *	 eip		}    from the same ring)
+ *	 orig_eax	}<- esi (copy src)
+ *	 - - - - - - - -
+ *	 fs		}
+ *	 es		}
+ *	 ds		}  SAVE_ALL state
+ *	 eax		}
+ *	  :		:
+ *	 ebx		}<- esp
+ *	----------------
+ *
+ * In order to deliver the nested exception properly, we need to shift
+ * everything from the return addr up to the error code so it sits
+ * just under the outer exception info.  This means that when we
+ * handle the exception, we do it in the context of the outer
+ * exception rather than starting a new one.
+ *
+ * The only caveat is that if the outer eax hasn't been restored yet
+ * (ie, it's still on stack), we need to insert its value into the
+ * SAVE_ALL state before going on, since it's usermode state which we
+ * eventually need to restore.
+ */
+ENTRY(xen_iret_crit_fixup)
+	/*
+	 * Paranoia: Make sure we're really coming from kernel space.
+	 * One could imagine a case where userspace jumps into the
+	 * critical range address, but just before the CPU delivers a
+	 * GP, it decides to deliver an interrupt instead.  Unlikely?
+	 * Definitely.  Easy to avoid?  Yes.  The Intel documents
+	 * explicitly say that the reported EIP for a bad jump is the
+	 * jump instruction itself, not the destination, but some
+	 * virtual environments get this wrong.
+	 */
+	movl PT_CS(%esp), %ecx
+	andl $SEGMENT_RPL_MASK, %ecx
+	cmpl $USER_RPL, %ecx
+	je 2f
+
+	lea PT_ORIG_EAX(%esp), %esi
+	lea PT_EFLAGS(%esp), %edi
+
+	/*
+	 * If eip is before iret_restore_end then stack
+	 * hasn't been restored yet.
+	 */
+	cmp $iret_restore_end, %eax
+	jae 1f
+
+	movl 0+4(%edi), %eax		/* copy EAX (just above top of frame) */
+	movl %eax, PT_EAX(%esp)
+
+	lea ESP_OFFSET(%edi), %edi	/* move dest up over saved regs */
+
+	/* set up the copy */
+1:	std
+	mov $PT_EIP / 4, %ecx		/* saved regs up to orig_eax */
+	rep movsl
+	cld
+
+	lea 4(%edi), %esp		/* point esp to new frame */
+2:	jmp xen_do_upcall
+
diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
new file mode 100644
index 00000000..53adefda
--- /dev/null
+++ b/arch/x86/xen/xen-asm_64.S
@@ -0,0 +1,159 @@
+/*
+ * Asm versions of Xen pv-ops, suitable for either direct use or
+ * inlining.  The inline versions are the same as the direct-use
+ * versions, with the pre- and post-amble chopped off.
+ *
+ * This code is encoded for size rather than absolute efficiency, with
+ * a view to being able to inline as much as possible.
+ *
+ * We only bother with direct forms (ie, vcpu in pda) of the
+ * operations here; the indirect forms are better handled in C, since
+ * they're generally too large to inline anyway.
+ */
+
+#include <asm/errno.h>
+#include <asm/percpu.h>
+#include <asm/processor-flags.h>
+#include <asm/segment.h>
+
+#include <xen/interface/xen.h>
+
+#include "xen-asm.h"
+
+ENTRY(xen_adjust_exception_frame)
+	mov 8+0(%rsp), %rcx
+	mov 8+8(%rsp), %r11
+	ret $16
+
+hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32
+/*
+ * Xen64 iret frame:
+ *
+ *	ss
+ *	rsp
+ *	rflags
+ *	cs
+ *	rip		<-- standard iret frame
+ *
+ *	flags
+ *
+ *	rcx		}
+ *	r11		}<-- pushed by hypercall page
+ * rsp->rax		}
+ */
+ENTRY(xen_iret)
+	pushq $0
+1:	jmp hypercall_iret
+ENDPATCH(xen_iret)
+RELOC(xen_iret, 1b+1)
+
+/*
+ * sysexit is not used for 64-bit processes, so it's only ever used to
+ * return to 32-bit compat userspace.
+ */
+ENTRY(xen_sysexit)
+	pushq $__USER32_DS
+	pushq %rcx
+	pushq $X86_EFLAGS_IF
+	pushq $__USER32_CS
+	pushq %rdx
+
+	pushq $0
+1:	jmp hypercall_iret
+ENDPATCH(xen_sysexit)
+RELOC(xen_sysexit, 1b+1)
+
+ENTRY(xen_sysret64)
+	/*
+	 * We're already on the usermode stack at this point, but
+	 * still with the kernel gs, so we can easily switch back
+	 */
+	movq %rsp, PER_CPU_VAR(old_rsp)
+	movq PER_CPU_VAR(kernel_stack), %rsp
+
+	pushq $__USER_DS
+	pushq PER_CPU_VAR(old_rsp)
+	pushq %r11
+	pushq $__USER_CS
+	pushq %rcx
+
+	pushq $VGCF_in_syscall
+1:	jmp hypercall_iret
+ENDPATCH(xen_sysret64)
+RELOC(xen_sysret64, 1b+1)
+
+ENTRY(xen_sysret32)
+	/*
+	 * We're already on the usermode stack at this point, but
+	 * still with the kernel gs, so we can easily switch back
+	 */
+	movq %rsp, PER_CPU_VAR(old_rsp)
+	movq PER_CPU_VAR(kernel_stack), %rsp
+
+	pushq $__USER32_DS
+	pushq PER_CPU_VAR(old_rsp)
+	pushq %r11
+	pushq $__USER32_CS
+	pushq %rcx
+
+	pushq $0
+1:	jmp hypercall_iret
+ENDPATCH(xen_sysret32)
+RELOC(xen_sysret32, 1b+1)
+
+/*
+ * Xen handles syscall callbacks much like ordinary exceptions, which
+ * means we have:
+ * - kernel gs
+ * - kernel rsp
+ * - an iret-like stack frame on the stack (including rcx and r11):
+ *	ss
+ *	rsp
+ *	rflags
+ *	cs
+ *	rip
+ *	r11
+ * rsp->rcx
+ *
+ * In all the entrypoints, we undo all that to make it look like a
+ * CPU-generated syscall/sysenter and jump to the normal entrypoint.
+ */
+
+.macro undo_xen_syscall
+	mov 0*8(%rsp), %rcx
+	mov 1*8(%rsp), %r11
+	mov 5*8(%rsp), %rsp
+.endm
+
+/* Normal 64-bit system call target */
+ENTRY(xen_syscall_target)
+	undo_xen_syscall
+	jmp system_call_after_swapgs
+ENDPROC(xen_syscall_target)
+
+#ifdef CONFIG_IA32_EMULATION
+
+/* 32-bit compat syscall target */
+ENTRY(xen_syscall32_target)
+	undo_xen_syscall
+	jmp ia32_cstar_target
+ENDPROC(xen_syscall32_target)
+
+/* 32-bit compat sysenter target */
+ENTRY(xen_sysenter_target)
+	undo_xen_syscall
+	jmp ia32_sysenter_target
+ENDPROC(xen_sysenter_target)
+
+#else /* !CONFIG_IA32_EMULATION */
+
+ENTRY(xen_syscall32_target)
+ENTRY(xen_sysenter_target)
+	lea 16(%rsp), %rsp	/* strip %rcx, %r11 */
+	mov $-ENOSYS, %rax
+	pushq $0
+	jmp hypercall_iret
+ENDPROC(xen_syscall32_target)
+ENDPROC(xen_sysenter_target)
+
+#endif	/* CONFIG_IA32_EMULATION */
diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
new file mode 100644
index 00000000..aaa7291c
--- /dev/null
+++ b/arch/x86/xen/xen-head.S
@@ -0,0 +1,55 @@
+/* Xen-specific pieces of head.S, intended to be included in the right
+	place in head.S */
+
+#ifdef CONFIG_XEN
+
+#include <linux/elfnote.h>
+#include <linux/init.h>
+
+#include <asm/boot.h>
+#include <asm/asm.h>
+#include <asm/page_types.h>
+
+#include <xen/interface/elfnote.h>
+#include <asm/xen/interface.h>
+
+	__INIT
+ENTRY(startup_xen)
+	cld
+#ifdef CONFIG_X86_32
+	mov %esi,xen_start_info
+	mov $init_thread_union+THREAD_SIZE,%esp
+#else
+	mov %rsi,xen_start_info
+	mov $init_thread_union+THREAD_SIZE,%rsp
+#endif
+	jmp xen_start_kernel
+
+	__FINIT
+
+.pushsection .text
+	.align PAGE_SIZE
+ENTRY(hypercall_page)
+	.skip PAGE_SIZE
+.popsection
+
+	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS,       .asciz "linux")
+	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION,  .asciz "2.6")
+	ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION,    .asciz "xen-3.0")
+#ifdef CONFIG_X86_32
+	ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE,      _ASM_PTR __PAGE_OFFSET)
+#else
+	ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE,      _ASM_PTR __START_KERNEL_map)
+#endif
+	ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,          _ASM_PTR startup_xen)
+	ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, _ASM_PTR hypercall_page)
+	ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .asciz "!writable_page_tables|pae_pgdir_above_4gb")
+	ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE,       .asciz "yes")
+	ELFNOTE(Xen, XEN_ELFNOTE_LOADER,         .asciz "generic")
+	ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,
+		.quad _PAGE_PRESENT; .quad _PAGE_PRESENT)
+	ELFNOTE(Xen, XEN_ELFNOTE_SUSPEND_CANCEL, .long 1)
+	ELFNOTE(Xen, XEN_ELFNOTE_HV_START_LOW,   _ASM_PTR __HYPERVISOR_VIRT_START)
+	ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET,   _ASM_PTR 0)
+
+#endif /*CONFIG_XEN */
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
new file mode 100644
index 00000000..b095739c
--- /dev/null
+++ b/arch/x86/xen/xen-ops.h
@@ -0,0 +1,123 @@
+#ifndef XEN_OPS_H
+#define XEN_OPS_H
+
+#include <linux/init.h>
+#include <linux/clocksource.h>
+#include <linux/irqreturn.h>
+#include <xen/xen-ops.h>
+
+/* These are code, but not functions.  Defined in entry.S */
+extern const char xen_hypervisor_callback[];
+extern const char xen_failsafe_callback[];
+
+extern void *xen_initial_gdt;
+
+struct trap_info;
+void xen_copy_trap_info(struct trap_info *traps);
+
+DECLARE_PER_CPU(struct vcpu_info, xen_vcpu_info);
+DECLARE_PER_CPU(unsigned long, xen_cr3);
+DECLARE_PER_CPU(unsigned long, xen_current_cr3);
+
+extern struct start_info *xen_start_info;
+extern struct shared_info xen_dummy_shared_info;
+extern struct shared_info *HYPERVISOR_shared_info;
+
+void xen_setup_mfn_list_list(void);
+void xen_setup_shared_info(void);
+void xen_build_mfn_list_list(void);
+void xen_setup_machphys_mapping(void);
+pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn);
+void xen_ident_map_ISA(void);
+void xen_reserve_top(void);
+extern unsigned long xen_max_p2m_pfn;
+
+void xen_set_pat(u64);
+
+char * __init xen_memory_setup(void);
+void __init xen_arch_setup(void);
+void __init xen_init_IRQ(void);
+void xen_enable_sysenter(void);
+void xen_enable_syscall(void);
+void xen_vcpu_restore(void);
+
+void xen_callback_vector(void);
+void xen_hvm_init_shared_info(void);
+void xen_unplug_emulated_devices(void);
+
+void __init xen_build_dynamic_phys_to_machine(void);
+
+void xen_init_irq_ops(void);
+void xen_setup_timer(int cpu);
+void xen_setup_runstate_info(int cpu);
+void xen_teardown_timer(int cpu);
+cycle_t xen_clocksource_read(void);
+void xen_setup_cpu_clockevents(void);
+void __init xen_init_time_ops(void);
+void __init xen_hvm_init_time_ops(void);
+
+irqreturn_t xen_debug_interrupt(int irq, void *dev_id);
+
+bool xen_vcpu_stolen(int vcpu);
+
+void xen_setup_vcpu_info_placement(void);
+
+#ifdef CONFIG_SMP
+void xen_smp_init(void);
+void __init xen_hvm_smp_init(void);
+
+extern cpumask_var_t xen_cpu_initialized_map;
+#else
+static inline void xen_smp_init(void) {}
+static inline void xen_hvm_smp_init(void) {}
+#endif
+
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+void __init xen_init_spinlocks(void);
+void __cpuinit xen_init_lock_cpu(int cpu);
+void xen_uninit_lock_cpu(int cpu);
+#else
+static inline void xen_init_spinlocks(void)
+{
+}
+static inline void xen_init_lock_cpu(int cpu)
+{
+}
+static inline void xen_uninit_lock_cpu(int cpu)
+{
+}
+#endif
+
+struct dom0_vga_console_info;
+
+#ifdef CONFIG_XEN_DOM0
+void __init xen_init_vga(const struct dom0_vga_console_info *, size_t size);
+#else
+static inline void __init xen_init_vga(const struct dom0_vga_console_info *info,
+				       size_t size)
+{
+}
+#endif
+
+/* Declare an asm function, along with symbols needed to make it
+   inlineable */
+#define DECL_ASM(ret, name, ...)		\
+	ret name(__VA_ARGS__);			\
+	extern char name##_end[];		\
+	extern char name##_reloc[]		\
+
+DECL_ASM(void, xen_irq_enable_direct, void);
+DECL_ASM(void, xen_irq_disable_direct, void);
+DECL_ASM(unsigned long, xen_save_fl_direct, void);
+DECL_ASM(void, xen_restore_fl_direct, unsigned long);
+
+/* These are not functions, and cannot be called normally */
+void xen_iret(void);
+void xen_sysexit(void);
+void xen_sysret32(void);
+void xen_sysret64(void);
+void xen_adjust_exception_frame(void);
+
+extern int xen_panic_handler_init(void);
+
+#endif /* XEN_OPS_H */