1 files changed, 16 insertions, 1 deletions

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 98bd683f31..9a3d769aa2 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -589,7 +589,15 @@ static uint64_t virtio_net_get_features(VirtIODevice *vdev, uint64_t features,
     if (!get_vhost_net(nc->peer)) {
         return features;
     }
-    return vhost_net_get_features(get_vhost_net(nc->peer), features);
+    features = vhost_net_get_features(get_vhost_net(nc->peer), features);
+    vdev->backend_features = features;
+
+    if (n->mtu_bypass_backend &&
+            (n->host_features & 1ULL << VIRTIO_NET_F_MTU)) {
+        features |= (1ULL << VIRTIO_NET_F_MTU);
+    }
+
+    return features;
 }
 
 static uint64_t virtio_net_bad_features(VirtIODevice *vdev)
@@ -640,6 +648,11 @@ static void virtio_net_set_features(VirtIODevice *vdev, uint64_t features)
     VirtIONet *n = VIRTIO_NET(vdev);
     int i;
 
+    if (n->mtu_bypass_backend &&
+            !virtio_has_feature(vdev->backend_features, VIRTIO_NET_F_MTU)) {
+        features &= ~(1ULL << VIRTIO_NET_F_MTU);
+    }
+
     virtio_net_set_multiqueue(n,
                               virtio_has_feature(features, VIRTIO_NET_F_MQ));
 
@@ -2093,6 +2106,8 @@ static Property virtio_net_properties[] = {
     DEFINE_PROP_UINT16("rx_queue_size", VirtIONet, net_conf.rx_queue_size,
                        VIRTIO_NET_RX_QUEUE_DEFAULT_SIZE),
     DEFINE_PROP_UINT16("host_mtu", VirtIONet, net_conf.mtu, 0),
+    DEFINE_PROP_BOOL("x-mtu-bypass-backend", VirtIONet, mtu_bypass_backend,
+                     true),
     DEFINE_PROP_END_OF_LIST(),
 };