1 files changed, 24 insertions, 14 deletions

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index bd13fdddbdc4..4924f83ed4f3 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1454,7 +1454,7 @@ static void apic_timer_expired(struct kvm_lapic *apic)
 	if (swait_active(q))
 		swake_up_one(q);
 
-	if (apic_lvtt_tscdeadline(apic))
+	if (apic_lvtt_tscdeadline(apic) || ktimer->hv_timer_in_use)
 		ktimer->expired_tscdeadline = ktimer->tscdeadline;
 }
 
@@ -1696,37 +1696,42 @@ static void cancel_hv_timer(struct kvm_lapic *apic)
 static bool start_hv_timer(struct kvm_lapic *apic)
 {
 	struct kvm_timer *ktimer = &apic->lapic_timer;
-	int r;
+	struct kvm_vcpu *vcpu = apic->vcpu;
+	bool expired;
 
 	WARN_ON(preemptible());
 	if (!kvm_x86_ops->set_hv_timer)
 		return false;
 
-	if (!apic_lvtt_period(apic) && atomic_read(&ktimer->pending))
-		return false;
-
 	if (!ktimer->tscdeadline)
 		return false;
 
-	r = kvm_x86_ops->set_hv_timer(apic->vcpu, ktimer->tscdeadline);
-	if (r < 0)
+	if (kvm_x86_ops->set_hv_timer(vcpu, ktimer->tscdeadline, &expired))
 		return false;
 
 	ktimer->hv_timer_in_use = true;
 	hrtimer_cancel(&ktimer->timer);
 
 	/*
-	 * Also recheck ktimer->pending, in case the sw timer triggered in
-	 * the window.  For periodic timer, leave the hv timer running for
-	 * simplicity, and the deadline will be recomputed on the next vmexit.
+	 * To simplify handling the periodic timer, leave the hv timer running
+	 * even if the deadline timer has expired, i.e. rely on the resulting
+	 * VM-Exit to recompute the periodic timer's target expiration.
 	 */
-	if (!apic_lvtt_period(apic) && (r || atomic_read(&ktimer->pending))) {
-		if (r)
+	if (!apic_lvtt_period(apic)) {
+		/*
+		 * Cancel the hv timer if the sw timer fired while the hv timer
+		 * was being programmed, or if the hv timer itself expired.
+		 */
+		if (atomic_read(&ktimer->pending)) {
+			cancel_hv_timer(apic);
+		} else if (expired) {
 			apic_timer_expired(apic);
-		return false;
+			cancel_hv_timer(apic);
+		}
 	}
 
-	trace_kvm_hv_timer_state(apic->vcpu->vcpu_id, true);
+	trace_kvm_hv_timer_state(vcpu->vcpu_id, ktimer->hv_timer_in_use);
+
 	return true;
 }
 
@@ -1750,8 +1755,13 @@ static void start_sw_timer(struct kvm_lapic *apic)
 static void restart_apic_timer(struct kvm_lapic *apic)
 {
 	preempt_disable();
+
+	if (!apic_lvtt_period(apic) && atomic_read(&apic->lapic_timer.pending))
+		goto out;
+
 	if (!start_hv_timer(apic))
 		start_sw_timer(apic);
+out:
 	preempt_enable();
 }