[dpdk-dev] [PATCH] vhost-user: fix enabling of queue pair

[Victor Kaplansky <victork@redhat.com>]

The VHOST_USER_SET_VRING_ENABLE request is sent for each queue in
queue-pair separately. So, a queue-pair should be considered
enabled only when both RX and TX queues are enabled.

The old code caused segfault when last TX queue was enabled.

Signed-off-by: Victor Kaplansky <victork@redhat.com>
---
 lib/librte_vhost/vhost_user/virtio-net-user.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/lib/librte_vhost/vhost_user/virtio-net-user.c b/lib/librte_vhost/vhost_user/virtio-net-user.c
index d07452a..c06e53e 100644
--- a/lib/librte_vhost/vhost_user/virtio-net-user.c
+++ b/lib/librte_vhost/vhost_user/virtio-net-user.c
@@ -317,21 +317,25 @@ user_set_vring_enable(struct vhost_device_ctx ctx,
 		      struct vhost_vring_state *state)
 {
 	struct virtio_net *dev = get_device(ctx);
-	uint16_t base_idx = state->index;
+	uint16_t idx = state->index;
+	uint16_t base_idx = (idx / VIRTIO_QNUM) * VIRTIO_QNUM;
 	int enable = (int)state->num;
+	int qpair_enabled;
 
 	RTE_LOG(INFO, VHOST_CONFIG,
 		"set queue enable: %d to qp idx: %d\n",
 		enable, state->index);
 
+	dev->virtqueue[idx]->enabled = enable;
+	qpair_enabled =
+		dev->virtqueue[base_idx + VIRTIO_RXQ]->enabled &&
+		dev->virtqueue[base_idx + VIRTIO_TXQ]->enabled;
+
 	if (notify_ops->vring_state_changed) {
 		notify_ops->vring_state_changed(dev, base_idx / VIRTIO_QNUM,
-						enable);
+						qpair_enabled);
 	}
 
-	dev->virtqueue[base_idx + VIRTIO_RXQ]->enabled = enable;
-	dev->virtqueue[base_idx + VIRTIO_TXQ]->enabled = enable;
-
 	return 0;
 }
 
-- 
--Victor