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-rw-r--r--arch/x86/kvm/timer.c16
1 files changed, 10 insertions, 6 deletions
diff --git a/arch/x86/kvm/timer.c b/arch/x86/kvm/timer.c
index 85cc743a8203..1baed414b57a 100644
--- a/arch/x86/kvm/timer.c
+++ b/arch/x86/kvm/timer.c
@@ -9,12 +9,16 @@ static int __kvm_timer_fn(struct kvm_vcpu *vcpu, struct kvm_timer *ktimer)
int restart_timer = 0;
wait_queue_head_t *q = &vcpu->wq;
- /* FIXME: this code should not know anything about vcpus */
- if (!atomic_inc_and_test(&ktimer->pending))
- set_bit(KVM_REQ_PENDING_TIMER, &vcpu->requests);
-
- if (!ktimer->reinject)
- atomic_set(&ktimer->pending, 1);
+ /*
+ * There is a race window between reading and incrementing, but we do
+ * not care about potentially loosing timer events in the !reinject
+ * case anyway.
+ */
+ if (ktimer->reinject || !atomic_read(&ktimer->pending)) {
+ /* FIXME: this code should not know anything about vcpus */
+ if (!atomic_inc_and_test(&ktimer->pending))
+ set_bit(KVM_REQ_PENDING_TIMER, &vcpu->requests);
+ }
if (waitqueue_active(q))
wake_up_interruptible(q);