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author | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
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committer | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
commit | 871480933a1c28f8a9fed4c4d34d06c439a7a422 (patch) | |
tree | 8718f573808810c2a1e8cb8fb6ac469093ca2784 /arch/x86/kernel/kvmclock.c | |
parent | 9d40ac5867b9aefe0722bc1f110b965ff294d30d (diff) | |
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Moved, renamed, and deleted files
The original directory structure was scattered and unorganized.
Changes are basically to make it look like kernel structure.
Diffstat (limited to 'arch/x86/kernel/kvmclock.c')
-rw-r--r-- | arch/x86/kernel/kvmclock.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c new file mode 100644 index 00000000..f8492da6 --- /dev/null +++ b/arch/x86/kernel/kvmclock.c @@ -0,0 +1,220 @@ +/* KVM paravirtual clock driver. A clocksource implementation + Copyright (C) 2008 Glauber de Oliveira Costa, Red Hat Inc. + + 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; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA +*/ + +#include <linux/clocksource.h> +#include <linux/kvm_para.h> +#include <asm/pvclock.h> +#include <asm/msr.h> +#include <asm/apic.h> +#include <linux/percpu.h> + +#include <asm/x86_init.h> +#include <asm/reboot.h> + +static int kvmclock = 1; +static int msr_kvm_system_time = MSR_KVM_SYSTEM_TIME; +static int msr_kvm_wall_clock = MSR_KVM_WALL_CLOCK; + +static int parse_no_kvmclock(char *arg) +{ + kvmclock = 0; + return 0; +} +early_param("no-kvmclock", parse_no_kvmclock); + +/* The hypervisor will put information about time periodically here */ +static DEFINE_PER_CPU_SHARED_ALIGNED(struct pvclock_vcpu_time_info, hv_clock); +static struct pvclock_wall_clock wall_clock; + +/* + * The wallclock is the time of day when we booted. Since then, some time may + * have elapsed since the hypervisor wrote the data. So we try to account for + * that with system time + */ +static unsigned long kvm_get_wallclock(void) +{ + struct pvclock_vcpu_time_info *vcpu_time; + struct timespec ts; + int low, high; + + low = (int)__pa_symbol(&wall_clock); + high = ((u64)__pa_symbol(&wall_clock) >> 32); + + native_write_msr(msr_kvm_wall_clock, low, high); + + vcpu_time = &get_cpu_var(hv_clock); + pvclock_read_wallclock(&wall_clock, vcpu_time, &ts); + put_cpu_var(hv_clock); + + return ts.tv_sec; +} + +static int kvm_set_wallclock(unsigned long now) +{ + return -1; +} + +static cycle_t kvm_clock_read(void) +{ + struct pvclock_vcpu_time_info *src; + cycle_t ret; + + preempt_disable_notrace(); + src = &__get_cpu_var(hv_clock); + ret = pvclock_clocksource_read(src); + preempt_enable_notrace(); + return ret; +} + +static cycle_t kvm_clock_get_cycles(struct clocksource *cs) +{ + return kvm_clock_read(); +} + +/* + * If we don't do that, there is the possibility that the guest + * will calibrate under heavy load - thus, getting a lower lpj - + * and execute the delays themselves without load. This is wrong, + * because no delay loop can finish beforehand. + * Any heuristics is subject to fail, because ultimately, a large + * poll of guests can be running and trouble each other. So we preset + * lpj here + */ +static unsigned long kvm_get_tsc_khz(void) +{ + struct pvclock_vcpu_time_info *src; + src = &per_cpu(hv_clock, 0); + return pvclock_tsc_khz(src); +} + +static void kvm_get_preset_lpj(void) +{ + unsigned long khz; + u64 lpj; + + khz = kvm_get_tsc_khz(); + + lpj = ((u64)khz * 1000); + do_div(lpj, HZ); + preset_lpj = lpj; +} + +static struct clocksource kvm_clock = { + .name = "kvm-clock", + .read = kvm_clock_get_cycles, + .rating = 400, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +int kvm_register_clock(char *txt) +{ + int cpu = smp_processor_id(); + int low, high, ret; + + low = (int)__pa(&per_cpu(hv_clock, cpu)) | 1; + high = ((u64)__pa(&per_cpu(hv_clock, cpu)) >> 32); + ret = native_write_msr_safe(msr_kvm_system_time, low, high); + printk(KERN_INFO "kvm-clock: cpu %d, msr %x:%x, %s\n", + cpu, high, low, txt); + + return ret; +} + +static void kvm_save_sched_clock_state(void) +{ +} + +static void kvm_restore_sched_clock_state(void) +{ + kvm_register_clock("primary cpu clock, resume"); +} + +#ifdef CONFIG_X86_LOCAL_APIC +static void __cpuinit kvm_setup_secondary_clock(void) +{ + /* + * Now that the first cpu already had this clocksource initialized, + * we shouldn't fail. + */ + WARN_ON(kvm_register_clock("secondary cpu clock")); +} +#endif + +/* + * After the clock is registered, the host will keep writing to the + * registered memory location. If the guest happens to shutdown, this memory + * won't be valid. In cases like kexec, in which you install a new kernel, this + * means a random memory location will be kept being written. So before any + * kind of shutdown from our side, we unregister the clock by writting anything + * that does not have the 'enable' bit set in the msr + */ +#ifdef CONFIG_KEXEC +static void kvm_crash_shutdown(struct pt_regs *regs) +{ + native_write_msr(msr_kvm_system_time, 0, 0); + kvm_disable_steal_time(); + native_machine_crash_shutdown(regs); +} +#endif + +static void kvm_shutdown(void) +{ + native_write_msr(msr_kvm_system_time, 0, 0); + kvm_disable_steal_time(); + native_machine_shutdown(); +} + +void __init kvmclock_init(void) +{ + if (!kvm_para_available()) + return; + + if (kvmclock && kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE2)) { + msr_kvm_system_time = MSR_KVM_SYSTEM_TIME_NEW; + msr_kvm_wall_clock = MSR_KVM_WALL_CLOCK_NEW; + } else if (!(kvmclock && kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE))) + return; + + printk(KERN_INFO "kvm-clock: Using msrs %x and %x", + msr_kvm_system_time, msr_kvm_wall_clock); + + if (kvm_register_clock("boot clock")) + return; + pv_time_ops.sched_clock = kvm_clock_read; + x86_platform.calibrate_tsc = kvm_get_tsc_khz; + x86_platform.get_wallclock = kvm_get_wallclock; + x86_platform.set_wallclock = kvm_set_wallclock; +#ifdef CONFIG_X86_LOCAL_APIC + x86_cpuinit.early_percpu_clock_init = + kvm_setup_secondary_clock; +#endif + x86_platform.save_sched_clock_state = kvm_save_sched_clock_state; + x86_platform.restore_sched_clock_state = kvm_restore_sched_clock_state; + machine_ops.shutdown = kvm_shutdown; +#ifdef CONFIG_KEXEC + machine_ops.crash_shutdown = kvm_crash_shutdown; +#endif + kvm_get_preset_lpj(); + clocksource_register_hz(&kvm_clock, NSEC_PER_SEC); + pv_info.paravirt_enabled = 1; + pv_info.name = "KVM"; + + if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE_STABLE_BIT)) + pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT); +} |