Index: sys/dev/virtio/virtqueue.h
===================================================================
--- sys/dev/virtio/virtqueue.h
+++ sys/dev/virtio/virtqueue.h
@@ -98,6 +98,8 @@
 int	 virtqueue_enqueue(struct virtqueue *vq, void *cookie,
 	     struct sglist *sg, int readable, int writable);
 void	*virtqueue_dequeue(struct virtqueue *vq, uint32_t *len);
+void	*virtqueue_poll_timeout(struct virtqueue *vq, uint32_t *len,
+	    sbintime_t sbt);
 void	*virtqueue_poll(struct virtqueue *vq, uint32_t *len);
 
 #endif /* _VIRTIO_VIRTQUEUE_H */
Index: sys/dev/virtio/virtqueue.c
===================================================================
--- sys/dev/virtio/virtqueue.c
+++ sys/dev/virtio/virtqueue.c
@@ -604,12 +604,15 @@
 }
 
 void *
-virtqueue_poll(struct virtqueue *vq, uint32_t *len)
+virtqueue_poll_timeout(struct virtqueue *vq, uint32_t *len, sbintime_t sbt)
 {
 	void *cookie;
+	sbintime_t timeout_at;
 
+	timeout_at = sbt == 0 ? 0 : getsbinuptime() + sbt;
 	VIRTIO_BUS_POLL(vq->vq_dev);
-	while ((cookie = virtqueue_dequeue(vq, len)) == NULL) {
+	while ((cookie = virtqueue_dequeue(vq, len)) == NULL &&
+	    (timeout_at == 0 || getsbinuptime() < timeout_at)) {
 		cpu_spinwait();
 		VIRTIO_BUS_POLL(vq->vq_dev);
 	}
@@ -617,6 +620,17 @@
 	return (cookie);
 }
 
+void *
+virtqueue_poll(struct virtqueue *vq, uint32_t *len)
+{
+	void *cookie;
+
+	cookie = virtqueue_poll_timeout(vq, len, 0);
+	/* No reason for this to have failed. */
+	MPASS(cookie != NULL);
+	return (cookie);
+}
+
 void *
 virtqueue_drain(struct virtqueue *vq, int *last)
 {