diff --git a/virtio-don-t-enable-notifications-during-polling.patch b/virtio-don-t-enable-notifications-during-polling.patch
new file mode 100644
index 0000000..cb77429
--- /dev/null
+++ b/virtio-don-t-enable-notifications-during-polling.patch
@@ -0,0 +1,146 @@
+From 0592b1e444e8ef7f00fb04a637dba72b732b70e4 Mon Sep 17 00:00:00 2001
+From: Stefan Hajnoczi <stefanha@redhat.com>
+Date: Mon, 9 Dec 2019 21:09:57 +0000
+Subject: [PATCH] virtio: don't enable notifications during polling
+
+Virtqueue notifications are not necessary during polling, so we disable
+them.  This allows the guest driver to avoid MMIO vmexits.
+Unfortunately the virtio-blk and virtio-scsi handler functions re-enable
+notifications, defeating this optimization.
+
+Fix virtio-blk and virtio-scsi emulation so they leave notifications
+disabled.  The key thing to remember for correctness is that polling
+always checks one last time after ending its loop, therefore it's safe
+to lose the race when re-enabling notifications at the end of polling.
+
+There is a measurable performance improvement of 5-10% with the null-co
+block driver.  Real-life storage configurations will see a smaller
+improvement because the MMIO vmexit overhead contributes less to
+latency.
+
+Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Message-Id: <20191209210957.65087-1-stefanha@redhat.com>
+Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
+Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
+---
+ hw/block/virtio-blk.c      |  9 +++++++--
+ hw/scsi/virtio-scsi.c      |  9 +++++++--
+ hw/virtio/virtio.c         | 12 ++++++------
+ include/hw/virtio/virtio.h |  1 +
+ 4 files changed, 21 insertions(+), 10 deletions(-)
+
+diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
+index 2db9804cfe..fbe2ed6779 100644
+--- a/hw/block/virtio-blk.c
++++ b/hw/block/virtio-blk.c
+@@ -766,13 +766,16 @@ bool virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq)
+ {
+     VirtIOBlockReq *req;
+     MultiReqBuffer mrb = {};
++    bool suppress_notifications = virtio_queue_get_notification(vq);
+     bool progress = false;
+ 
+     aio_context_acquire(blk_get_aio_context(s->blk));
+     blk_io_plug(s->blk);
+ 
+     do {
+-        virtio_queue_set_notification(vq, 0);
++        if (suppress_notifications) {
++            virtio_queue_set_notification(vq, 0);
++        }
+ 
+         while ((req = virtio_blk_get_request(s, vq))) {
+             progress = true;
+@@ -783,7 +786,9 @@ bool virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq)
+             }
+         }
+ 
+-        virtio_queue_set_notification(vq, 1);
++        if (suppress_notifications) {
++            virtio_queue_set_notification(vq, 1);
++        }
+     } while (!virtio_queue_empty(vq));
+ 
+     if (mrb.num_reqs) {
+diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
+index 8b9e5e2b49..eddb13e7c6 100644
+--- a/hw/scsi/virtio-scsi.c
++++ b/hw/scsi/virtio-scsi.c
+@@ -594,12 +594,15 @@ bool virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
+ {
+     VirtIOSCSIReq *req, *next;
+     int ret = 0;
++    bool suppress_notifications = virtio_queue_get_notification(vq);
+     bool progress = false;
+ 
+     QTAILQ_HEAD(, VirtIOSCSIReq) reqs = QTAILQ_HEAD_INITIALIZER(reqs);
+ 
+     do {
+-        virtio_queue_set_notification(vq, 0);
++        if (suppress_notifications) {
++            virtio_queue_set_notification(vq, 0);
++        }
+ 
+         while ((req = virtio_scsi_pop_req(s, vq))) {
+             progress = true;
+@@ -619,7 +622,9 @@ bool virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
+             }
+         }
+ 
+-        virtio_queue_set_notification(vq, 1);
++        if (suppress_notifications) {
++            virtio_queue_set_notification(vq, 1);
++        }
+     } while (ret != -EINVAL && !virtio_queue_empty(vq));
+ 
+     QTAILQ_FOREACH_SAFE(req, &reqs, next, next) {
+diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
+index 90971f4afa..daa8250332 100644
+--- a/hw/virtio/virtio.c
++++ b/hw/virtio/virtio.c
+@@ -390,6 +390,11 @@ void virtio_queue_set_notification(VirtQueue *vq, int enable)
+     rcu_read_unlock();
+ }
+ 
++bool virtio_queue_get_notification(VirtQueue *vq)
++{
++    return vq->notification;
++}
++
+ int virtio_queue_ready(VirtQueue *vq)
+ {
+     return vq->vring.avail != 0;
+@@ -2572,17 +2577,12 @@ static bool virtio_queue_host_notifier_aio_poll(void *opaque)
+ {
+     EventNotifier *n = opaque;
+     VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
+-    bool progress;
+ 
+     if (!vq->vring.desc || virtio_queue_empty(vq)) {
+         return false;
+     }
+ 
+-    progress = virtio_queue_notify_aio_vq(vq);
+-
+-    /* In case the handler function re-enabled notifications */
+-    virtio_queue_set_notification(vq, 0);
+-    return progress;
++    return virtio_queue_notify_aio_vq(vq);
+ }
+ 
+ static void virtio_queue_host_notifier_aio_poll_end(EventNotifier *n)
+diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
+index ca2fbaeb35..7394715407 100644
+--- a/include/hw/virtio/virtio.h
++++ b/include/hw/virtio/virtio.h
+@@ -229,6 +229,7 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id);
+ 
+ void virtio_notify_config(VirtIODevice *vdev);
+ 
++bool virtio_queue_get_notification(VirtQueue *vq);
+ void virtio_queue_set_notification(VirtQueue *vq, int enable);
+ 
+ int virtio_queue_ready(VirtQueue *vq);
+-- 
+2.27.0
+