Messages in this thread Patch in this message | | | Date | Mon, 28 Feb 2011 08:22:32 -0800 | From | Greg KH <> | Subject | [11/68] x86/pvclock: Zero last_value on resume |
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2.6.32-longterm review patch. If anyone has any objections, please let us know.
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From: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
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 <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- arch/x86/include/asm/pvclock.h | 1 + arch/x86/kernel/pvclock.c | 5 +++++ arch/x86/xen/time.c | 2 ++ 3 files changed, 8 insertions(+)
--- a/arch/x86/include/asm/pvclock.h +++ b/arch/x86/include/asm/pvclock.h @@ -10,5 +10,6 @@ unsigned long pvclock_tsc_khz(struct pvc 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 */ --- a/arch/x86/kernel/pvclock.c +++ b/arch/x86/kernel/pvclock.c @@ -111,6 +111,11 @@ unsigned long pvclock_tsc_khz(struct pvc 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; --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -424,6 +424,8 @@ void xen_timer_resume(void) { int cpu; + pvclock_resume(); + if (xen_clockevent != &xen_vcpuop_clockevent) return;
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