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: Michael S. Tsirkin <[email protected]> Signed-off-by: Avi Kivity <[email protected]>
cail · Jan 25, 2010 · b6a114d · b6a114d
1 parent cb289d6
commit b6a114d
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
@@ -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