KVM: only abort guest entry if timer count goes from 0->1

[linux-2.6-omap-h63xx.git] / arch / x86 / kvm / i8254.c

diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 9e3391e9a1b7bd45cd6965f8ab9bb03dab317dba..c0f7872a9124873ac9c01937bd4400ca2f3fe47b 100644 (file)
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -198,14 +198,11 @@ static int __pit_timer_fn(struct kvm_kpit_state *ps)
        struct kvm_vcpu *vcpu0 = ps->pit->kvm->vcpus[0];
        struct kvm_kpit_timer *pt = &ps->pit_timer;
 
-       atomic_inc(&pt->pending);
-       smp_mb__after_atomic_inc();
-       if (vcpu0) {
+       if (!atomic_inc_and_test(&pt->pending))
                set_bit(KVM_REQ_PENDING_TIMER, &vcpu0->requests);
-               if (waitqueue_active(&vcpu0->wq)) {
-                       vcpu0->arch.mp_state = KVM_MP_STATE_RUNNABLE;
-                       wake_up_interruptible(&vcpu0->wq);
-               }
+       if (vcpu0 && waitqueue_active(&vcpu0->wq)) {
+               vcpu0->arch.mp_state = KVM_MP_STATE_RUNNABLE;
+               wake_up_interruptible(&vcpu0->wq);
        }
 
        pt->timer.expires = ktime_add_ns(pt->timer.expires, pt->period);