From: Jeremy Fitzhardinge Date: Mon, 25 Oct 2010 23:53:46 +0000 (-0700) Subject: x86/pvclock: Zero last_value on resume X-Git-Tag: v2.6.35.12~158 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ac9a0f1a28f560f2c65ee6e2ae5b750fac9f14cb;p=thirdparty%2Fkernel%2Fstable.git x86/pvclock: Zero last_value on resume commit e7a3481c0246c8e45e79c629efd63b168e91fcda upstream. If the guest domain has been suspend/resumed or migrated, then the system clock backing the pvclock clocksource may revert to a smaller value (ie, can be non-monotonic across the migration/save-restore). Make sure we zero last_value in that case so that the domain continues to see clock updates. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman Signed-off-by: Andi Kleen --- diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h index cd02f324aa6b3..6226870d11cde 100644 --- a/arch/x86/include/asm/pvclock.h +++ b/arch/x86/include/asm/pvclock.h @@ -11,5 +11,6 @@ unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src); void pvclock_read_wallclock(struct pvclock_wall_clock *wall, struct pvclock_vcpu_time_info *vcpu, struct timespec *ts); +void pvclock_resume(void); #endif /* _ASM_X86_PVCLOCK_H */ diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c index 239427ca02af0..a4f07c1cfc87a 100644 --- a/arch/x86/kernel/pvclock.c +++ b/arch/x86/kernel/pvclock.c @@ -120,6 +120,11 @@ unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src) static atomic64_t last_value = ATOMIC64_INIT(0); +void pvclock_resume(void) +{ + atomic64_set(&last_value, 0); +} + cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src) { struct pvclock_shadow_time shadow; diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c index a86df42e46adb..41eb583adc8dc 100644 --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -425,6 +425,8 @@ void xen_timer_resume(void) { int cpu; + pvclock_resume(); + if (xen_clockevent != &xen_vcpuop_clockevent) return;