vdpa/mlx5: Return error on vlan ctrl commands if not supported

Check if VIRTIO_NET_F_CTRL_VLAN is negotiated and return error if
control VQ command is received.
Signed-off-by: NEli Cohen <elic@nvidia.com>
Message-Id: <20221114131759.57883-3-elic@nvidia.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NJason Wang <jasowang@redhat.com>
Acked-by: NEugenio Pérez <eperezma@redhat.com>

drivers/vdpa/mlx5/net/mlx5_vnet.c

@@ -1823,6 +1823,9 @@ static virtio_net_ctrl_ack handle_ctrl_vlan(struct mlx5_vdpa_dev *mvdev, u8 cmd)
 	size_t read;
 	u16 id;
 
+	if (!(ndev->mvdev.actual_features & BIT_ULL(VIRTIO_NET_F_CTRL_VLAN)))
+		return status;
+
 	switch (cmd) {
 	case VIRTIO_NET_CTRL_VLAN_ADD:
 		read = vringh_iov_pull_iotlb(&cvq->vring, &cvq->riov, &vlan, sizeof(vlan));