vhost-user: save features if the char dev is closed

That way the state can be correctly restored when the device is opened
again. This might happen if the backend is restarted.

Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1738768
Reported-by: Pei Zhang <pezhang@redhat.com>
Fixes: 6ab79a20af3a ("do not call vhost_net_cleanup() on running net from char user event")
Cc: ddstreet@canonical.com
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Adrian Moreno <amorenoz@redhat.com>
Message-Id: <20190924162044.11414-1-amorenoz@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit c6beefd674fff8d41b90365dfccad32e53a5abcb)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

diff --git a/net/vhost-user.c b/net/vhost-user.c
index 51921de443996a06574aa81425693da290ba1f97..014199d6008f380ef0f296655339356b4753a6d3 100644 (file)
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -235,6 +235,10 @@ static void chr_closed_bh(void *opaque)
 
     s = DO_UPCAST(NetVhostUserState, nc, ncs[0]);
 
+    if (s->vhost_net) {
+        s->acked_features = vhost_net_get_acked_features(s->vhost_net);
+    }
+
     qmp_set_link(name, false, &err);
 
     qemu_chr_fe_set_handlers(&s->chr, NULL, NULL, net_vhost_user_event,