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Diffstat (limited to 'arch/x86/kernel/pvclock.c')
-rw-r--r--arch/x86/kernel/pvclock.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c
index 99bfc025111d..06c58ce46762 100644
--- a/arch/x86/kernel/pvclock.c
+++ b/arch/x86/kernel/pvclock.c
@@ -61,11 +61,16 @@ void pvclock_resume(void)
u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src)
{
unsigned version;
- cycle_t ret;
u8 flags;
do {
- version = __pvclock_read_cycles(src, &ret, &flags);
+ version = src->version;
+ /* Make the latest version visible */
+ smp_rmb();
+
+ flags = src->flags;
+ /* Make sure that the version double-check is last. */
+ smp_rmb();
} while ((src->version & 1) || version != src->version);
return flags & valid_flags;
@@ -80,6 +85,8 @@ cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src)
do {
version = __pvclock_read_cycles(src, &ret, &flags);
+ /* Make sure that the version double-check is last. */
+ smp_rmb();
} while ((src->version & 1) || version != src->version);
if (unlikely((flags & PVCLOCK_GUEST_STOPPED) != 0)) {