vhost: enable packed virtqueues

This patch enables the code do enqueue and dequeue packed to/from a
packed virtqueue.  Add feature bit for packed virtqueues as defined in
Virtio 1.1 draft.

Signed-off-by: Jens Freimann <jfreimann@redhat.com>
Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>

lib/librte_vhost/vhost.h

@@ -181,6 +181,7 @@ struct vhost_msg {
 				(1ULL << VIRTIO_NET_F_GUEST_ANNOUNCE) | \
 				(1ULL << VIRTIO_NET_F_MQ)      | \
 				(1ULL << VIRTIO_F_VERSION_1)   | \
+				(1ULL << VIRTIO_F_PACKED)      | \
 				(1ULL << VHOST_F_LOG_ALL)      | \
 				(1ULL << VHOST_USER_F_PROTOCOL_FEATURES) | \
 				(1ULL << VIRTIO_NET_F_GSO) | \

lib/librte_vhost/virtio_net.c

@@ -824,7 +824,9 @@ rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
 	if (!dev)
 		return 0;
 
-	if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF))
+	if (dev->features & (1ULL << VIRTIO_F_PACKED))
+		return vhost_enqueue_burst_1_1(dev, queue_id, pkts, count);
+	else if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF))
 		return virtio_dev_merge_rx(dev, queue_id, pkts, count);
 	else
 		return virtio_dev_rx(dev, queue_id, pkts, count);
@@ -1456,6 +1458,9 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
 	if (unlikely(vq->enabled == 0))
 		goto out_access_unlock;
 
+	if (dev->features & (1ULL << VIRTIO_F_PACKED))
+		return vhost_dequeue_burst_1_1(dev, vq, mbuf_pool, pkts, count);
+
 	vq->batch_copy_nb_elems = 0;
 
 	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))