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Commit 5d87db71 authored by Radim Krčmář's avatar Radim Krčmář Committed by Paolo Bonzini
Browse files

KVM: x86: add apic_timer_expired() 



Make the code reusable.

If the timer was already pending, we shouldn't be waiting in a queue,
so wake_up can be skipped, simplifying the path.

There is no 'reinject' case => the comment is removed.
Current race behaves correctly.

Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 91690bf3

arch/x86/kvm/lapic.c

+21 −16
Original line number Diff line number Diff line
@@ -1050,6 +1050,26 @@ static void update_divide_count(struct kvm_lapic *apic) 
				   apic->divide_count);

}



static void apic_timer_expired(struct kvm_lapic *apic)

{

	struct kvm_vcpu *vcpu = apic->vcpu;

	wait_queue_head_t *q = &vcpu->wq;



	/*

	 * Note: KVM_REQ_PENDING_TIMER is implicitly checked in

	 * vcpu_enter_guest.

	 */

	if (atomic_read(&apic->lapic_timer.pending))

		return;



	atomic_inc(&apic->lapic_timer.pending);

	/* FIXME: this code should not know anything about vcpus */

	kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu);



	if (waitqueue_active(q))

		wake_up_interruptible(q);

}



static void start_apic_timer(struct kvm_lapic *apic)

{

	ktime_t now;
@@ -1554,23 +1574,8 @@ static enum hrtimer_restart apic_timer_fn(struct hrtimer *data) 
{

	struct kvm_timer *ktimer = container_of(data, struct kvm_timer, timer);

	struct kvm_lapic *apic = container_of(ktimer, struct kvm_lapic, lapic_timer);

	struct kvm_vcpu *vcpu = apic->vcpu;

	wait_queue_head_t *q = &vcpu->wq;



	/*

	 * There is a race window between reading and incrementing, but we do

	 * not care about potentially losing timer events in the !reinject

	 * case anyway. Note: KVM_REQ_PENDING_TIMER is implicitly checked

	 * in vcpu_enter_guest.

	 */

	if (!atomic_read(&ktimer->pending)) {

		atomic_inc(&ktimer->pending);

		/* FIXME: this code should not know anything about vcpus */

		kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu);

	}



	if (waitqueue_active(q))

		wake_up_interruptible(q);

	apic_timer_expired(apic);



	if (lapic_is_periodic(apic)) {

		hrtimer_add_expires_ns(&ktimer->timer, ktimer->period);