virtio_net: Update xdp_features with xdp multi-buff

Now virtio-net supports xdp multi-buffer so add it to xdp_features.
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/bpf/60c76cd63a0246db785606e8891b925fd5c9bf06.1675763384.git.lorenzo@kernel.org

drivers/net/virtio_net.c

@@ -3281,7 +3281,7 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
 				virtnet_clear_guest_offloads(vi);
 		}
 		if (!old_prog)
-			xdp_features_set_redirect_target(dev, false);
+			xdp_features_set_redirect_target(dev, true);
 	} else {
 		xdp_features_clear_redirect_target(dev);
 		vi->xdp_enabled = false;
@@ -3940,8 +3940,10 @@ static int virtnet_probe(struct virtio_device *vdev)
 	INIT_WORK(&vi->config_work, virtnet_config_changed_work);
 	spin_lock_init(&vi->refill_lock);
 
-	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
+	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF)) {
 		vi->mergeable_rx_bufs = true;
+		dev->xdp_features |= NETDEV_XDP_ACT_RX_SG;
+	}
 
 	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_NOTF_COAL)) {
 		vi->rx_usecs = 0;