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Commit b6a114d2 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin Committed by Marcelo Tosatti
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KVM: fix spurious interrupt with irqfd 



kvm didn't clear irqfd counter on deassign, as a result we could get a
spurious interrupt when irqfd is assigned back. this leads to poor
performance and, in theory, guest crash.

Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent cb289d62

virt/kvm/eventfd.c

+2 −1
Original line number Diff line number Diff line
@@ -72,12 +72,13 @@ static void 
irqfd_shutdown(struct work_struct *work)

{

	struct _irqfd *irqfd = container_of(work, struct _irqfd, shutdown);

	u64 cnt;



	/*

	 * Synchronize with the wait-queue and unhook ourselves to prevent

	 * further events.

	 */

	remove_wait_queue(irqfd->wqh, &irqfd->wait);

	eventfd_ctx_remove_wait_queue(irqfd->eventfd, &irqfd->wait, &cnt);



	/*

	 * We know no new events will be scheduled at this point, so block