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Diffstat (limited to 'arch/x86/kernel/kvm.c')
-rw-r--r--arch/x86/kernel/kvm.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 94f643484300..e354cc6446ab 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -609,7 +609,7 @@ static inline void check_zero(void)
u8 ret;
u8 old;
- old = ACCESS_ONCE(zero_stats);
+ old = READ_ONCE(zero_stats);
if (unlikely(old)) {
ret = cmpxchg(&zero_stats, old, 0);
/* This ensures only one fellow resets the stat */
@@ -727,6 +727,7 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
int cpu;
u64 start;
unsigned long flags;
+ __ticket_t head;
if (in_nmi())
return;
@@ -768,11 +769,15 @@ __visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
*/
__ticket_enter_slowpath(lock);
+ /* make sure enter_slowpath, which is atomic does not cross the read */
+ smp_mb__after_atomic();
+
/*
* check again make sure it didn't become free while
* we weren't looking.
*/
- if (ACCESS_ONCE(lock->tickets.head) == want) {
+ head = READ_ONCE(lock->tickets.head);
+ if (__tickets_equal(head, want)) {
add_stats(TAKEN_SLOW_PICKUP, 1);
goto out;
}
@@ -803,8 +808,8 @@ static void kvm_unlock_kick(struct arch_spinlock *lock, __ticket_t ticket)
add_stats(RELEASED_SLOW, 1);
for_each_cpu(cpu, &waiting_cpus) {
const struct kvm_lock_waiting *w = &per_cpu(klock_waiting, cpu);
- if (ACCESS_ONCE(w->lock) == lock &&
- ACCESS_ONCE(w->want) == ticket) {
+ if (READ_ONCE(w->lock) == lock &&
+ READ_ONCE(w->want) == ticket) {
add_stats(RELEASED_SLOW_KICKED, 1);
kvm_kick_cpu(cpu);
break;