x86/pvclock: Zero last_value on resume (e7a3481c) · Commits · 戴 / test

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>

arch/x86/include/asm/pvclock.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -11,6 +11,7 @@ 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);

		/*
		* Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,

arch/x86/kernel/pvclock.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -83,6 +83,11 @@ 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;

arch/x86/xen/time.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -426,6 +426,8 @@ void xen_timer_resume(void)
		{
		int cpu;

		pvclock_resume();

		if (xen_clockevent != &xen_vcpuop_clockevent)
		return;

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