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authorJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>2010-10-25 16:53:46 -0700
committerPaul Gortmaker <paul.gortmaker@windriver.com>2011-06-26 12:46:41 -0400
commit7d328bebd36bd80ade9e15e7bd12349b607aa97b (patch)
treeaee39695d5f6cc0fcde6024579a99c9d11653d1c /arch
parent021a4a6c35951860fd978badd6018ccf4878db9e (diff)
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 <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/asm/pvclock.h1
-rw-r--r--arch/x86/kernel/pvclock.c5
-rw-r--r--arch/x86/xen/time.c2
3 files changed, 8 insertions, 0 deletions
diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h
index 53235fd5f8ce..daaacab89143 100644
--- a/arch/x86/include/asm/pvclock.h
+++ b/arch/x86/include/asm/pvclock.h
@@ -10,5 +10,6 @@ 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 dfdfe4662e05..b12fe8de6652 100644
--- a/arch/x86/kernel/pvclock.c
+++ b/arch/x86/kernel/pvclock.c
@@ -111,6 +111,11 @@ 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 e90360ff4a08..a05bda6bf1ef 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;