1 files changed, 79 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
new file mode 100644
index 00000000..0a630dd4
--- /dev/null
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -0,0 +1,79 @@
+/*
+ * HyperV  Detection code.
+ *
+ * Copyright (C) 2010, Novell, Inc.
+ * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/time.h>
+#include <linux/clocksource.h>
+#include <linux/module.h>
+#include <asm/processor.h>
+#include <asm/hypervisor.h>
+#include <asm/hyperv.h>
+#include <asm/mshyperv.h>
+
+struct ms_hyperv_info ms_hyperv;
+EXPORT_SYMBOL_GPL(ms_hyperv);
+
+static bool __init ms_hyperv_platform(void)
+{
+	u32 eax;
+	u32 hyp_signature[3];
+
+	if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
+		return false;
+
+	cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
+	      &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
+
+	return eax >= HYPERV_CPUID_MIN &&
+		eax <= HYPERV_CPUID_MAX &&
+		!memcmp("Microsoft Hv", hyp_signature, 12);
+}
+
+static cycle_t read_hv_clock(struct clocksource *arg)
+{
+	cycle_t current_tick;
+	/*
+	 * Read the partition counter to get the current tick count. This count
+	 * is set to 0 when the partition is created and is incremented in
+	 * 100 nanosecond units.
+	 */
+	rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
+	return current_tick;
+}
+
+static struct clocksource hyperv_cs = {
+	.name		= "hyperv_clocksource",
+	.rating		= 400, /* use this when running on Hyperv*/
+	.read		= read_hv_clock,
+	.mask		= CLOCKSOURCE_MASK(64),
+};
+
+static void __init ms_hyperv_init_platform(void)
+{
+	/*
+	 * Extract the features and hints
+	 */
+	ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
+	ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
+
+	printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n",
+	       ms_hyperv.features, ms_hyperv.hints);
+
+	clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
+}
+
+const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
+	.name			= "Microsoft HyperV",
+	.detect			= ms_hyperv_platform,
+	.init_platform		= ms_hyperv_init_platform,
+};
+EXPORT_SYMBOL(x86_hyper_ms_hyperv);