From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Mon, 12 Aug 2013 09:08:09 +0000 (+0200)
Subject: virtio: clear signalled_used_valid when switching from dataplane
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=6793dfd1b6a99a79b9f2e3c4d6625ccd6513f240;p=qemu.git

virtio: clear signalled_used_valid when switching from dataplane

When the dataplane thread stops, its vring.c implementation synchronizes
vring state back to virtio.c so we can continue emulating the virtio
device.

This patch ensures that virtio.c's signalled_used_valid flag is reset so
that we do not suppress guest notifications due to stale signalled_used
values.

Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---

diff --git a/hw/virtio/dataplane/vring.c b/hw/virtio/dataplane/vring.c
index 82cc151b17..351a343806 100644
--- a/hw/virtio/dataplane/vring.c
+++ b/hw/virtio/dataplane/vring.c
@@ -52,6 +52,7 @@ bool vring_setup(Vring *vring, VirtIODevice *vdev, int n)
 void vring_teardown(Vring *vring, VirtIODevice *vdev, int n)
 {
     virtio_queue_set_last_avail_idx(vdev, n, vring->last_avail_idx);
+    virtio_queue_invalidate_signalled_used(vdev, n);
 
     hostmem_finalize(&vring->hostmem);
 }
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 09f62c6c70..706bdf4c46 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -1059,6 +1059,11 @@ void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx)
     vdev->vq[n].last_avail_idx = idx;
 }
 
+void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n)
+{
+    vdev->vq[n].signalled_used_valid = false;
+}
+
 VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n)
 {
     return vdev->vq + n;
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index d7e9e0fc8a..a90522d6d6 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -237,6 +237,7 @@ hwaddr virtio_queue_get_used_size(VirtIODevice *vdev, int n);
 hwaddr virtio_queue_get_ring_size(VirtIODevice *vdev, int n);
 uint16_t virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n);
 void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx);
+void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n);
 VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n);
 uint16_t virtio_get_queue_index(VirtQueue *vq);
 int virtio_queue_get_id(VirtQueue *vq);