[PATCH v4 20/20] vhost: by default disable packed virtqueues

[Jens Freimann <jfreimann@redhat.com>]

From: Yuanhan Liu <yuanhan.liu@linux.intel.com>

Add a built-time config option to enable packed virtqueues.
This config option activates 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>
---
 config/common_base            |  1 +
 lib/librte_vhost/socket.c     |  5 +++++
 lib/librte_vhost/vhost.h      |  1 +
 lib/librte_vhost/virtio_net.c | 16 +++++++++++-----
 4 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/config/common_base b/config/common_base
index 538cc520d..83a8d6e67 100644
--- a/config/common_base
+++ b/config/common_base
@@ -802,6 +802,7 @@ CONFIG_RTE_LIBRTE_PDUMP=y
 CONFIG_RTE_LIBRTE_VHOST=n
 CONFIG_RTE_LIBRTE_VHOST_NUMA=n
 CONFIG_RTE_LIBRTE_VHOST_DEBUG=n
+CONFIG_RTE_LIBRTE_VHOST_PQ=n
 
 #
 # Compile vhost PMD
diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c
index 636fc25c6..024fd26b8 100644
--- a/lib/librte_vhost/socket.c
+++ b/lib/librte_vhost/socket.c
@@ -850,6 +850,11 @@ rte_vhost_driver_register(const char *path, uint64_t flags)
 		vsocket->features &= ~(1ULL << VIRTIO_F_IOMMU_PLATFORM);
 	}
 
+#ifdef RTE_LIBRTE_VHOST_PQ
+		vsocket->features |= (1ULL << VIRTIO_F_RING_PACKED);
+		vsocket->features &= ~(1ULL << VIRTIO_RING_F_INDIRECT_DESC);
+#endif
+
 	if ((flags & RTE_VHOST_USER_CLIENT) != 0) {
 		vsocket->reconnect = !(flags & RTE_VHOST_USER_NO_RECONNECT);
 		if (vsocket->reconnect && reconn_tid == 0) {
diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 3e189f22a..1728f9f23 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -209,6 +209,7 @@ struct vhost_msg {
 				(1ULL << VIRTIO_NET_F_GUEST_ANNOUNCE) | \
 				(1ULL << VIRTIO_NET_F_MQ)      | \
 				(1ULL << VIRTIO_F_VERSION_1)   | \
+				(1ULL << VIRTIO_F_RING_PACKED) | \
 				(1ULL << VHOST_F_LOG_ALL)      | \
 				(1ULL << VHOST_USER_F_PROTOCOL_FEATURES) | \
 				(1ULL << VIRTIO_NET_F_GSO) | \
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 523e7d9f6..d670751ea 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -928,12 +928,14 @@ rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
 		return 0;
 	}
 
-	if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF))
-		return virtio_dev_merge_rx(dev, queue_id, pkts, count);
-	else if (vq_is_packed(dev))
-		return vhost_enqueue_burst_packed(dev, queue_id, pkts, count);
-	else
+	if (vq_is_packed(dev)) {
+		if (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF))
+			return virtio_dev_merge_rx(dev, queue_id, pkts, count);
+		else
+			return vhost_enqueue_burst_packed(dev, queue_id, pkts, count);
+	} else {
 		return virtio_dev_rx(dev, queue_id, pkts, count);
+	}
 }
 
 static inline bool
@@ -1595,6 +1597,10 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
 	if (unlikely(vq->enabled == 0))
 		goto out_access_unlock;
 
+	if (vq_is_packed(dev))
+		return vhost_dequeue_burst_packed(dev, vq, mbuf_pool, pkts,
+						  count);
+
 	vq->batch_copy_nb_elems = 0;
 
 	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
-- 
2.14.3