net/virtio: reject unsupported Rx multi-queue modes

This driver supports none of DCB, RSS or VMDQ modes, therefore must
check and return error if configured incorrectly.

Virtio can distribute Rx packets across multi-queue, but there is
no controls (algorithm, redirection table, hash function) except
number of Rx queues and ETH_MQ_RX_NONE is the best fit meaning
no method is enforced on how to route packets to MQs.

Fixes: c1f8630 ("virtio: add new driver")
Cc: stable@dpdk.org

Signed-off-by: Dilshod Urazov <dilshod.urazov@oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

drivers/net/virtio/virtio_ethdev.c

@@ -2066,6 +2066,13 @@ virtio_dev_configure(struct rte_eth_dev *dev)
 	PMD_INIT_LOG(DEBUG, "configure");
 	req_features = VIRTIO_PMD_DEFAULT_GUEST_FEATURES;
 
+	if (rxmode->mq_mode != ETH_MQ_RX_NONE) {
+		PMD_DRV_LOG(ERR,
+			"Unsupported Rx multi queue mode %d",
+			rxmode->mq_mode);
+		return -EINVAL;
+	}
+
 	if (dev->data->dev_conf.intr_conf.rxq) {
 		ret = virtio_init_device(dev, hw->req_guest_features);
 		if (ret < 0)