[dpdk-dev] [PATCH v2] vhost-user: fix enabling of queue pair

[Yuanhan Liu <yuanhan.liu@linux.intel.com>]

From: Victor Kaplansky <victork@redhat.com>

The VHOST_USER_SET_VRING_ENABLE request was sent for each queue-pair.
However, it's changed to be sent per queue in the queue-pair by QEMU
commit dc3db6ad ("vhost-user: start/stop all rings"). The change
is reasonable, as we send all other request per queue, instead of
queue-pair.

Hence we should do proper changes to adapt to the QEMU change here.
Otherwise, a segfault will be triggered when last TX queue was enabled.

[ commit log reword --  Yuanhan Liu ]

Signed-off-by: Victor Kaplansky <victork@redhat.com>
Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
---

v2: invoke vring_state_changed() callback per-vring as well

This fixes a fatal issue, without that MQ will not work properly.
Seems that Victor is busy at something else (or out of office so
far), hence I sent v2 on behalf of him.

---
 lib/librte_vhost/vhost_user/virtio-net-user.c | 7 ++-----
 1 file changed, 2 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..b2ada9f 100644
--- a/lib/librte_vhost/vhost_user/virtio-net-user.c
+++ b/lib/librte_vhost/vhost_user/virtio-net-user.c
@@ -317,7 +317,6 @@ 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;
 	int enable = (int)state->num;
 
 	RTE_LOG(INFO, VHOST_CONFIG,
@@ -325,12 +324,10 @@ user_set_vring_enable(struct vhost_device_ctx ctx,
 		enable, state->index);
 
 	if (notify_ops->vring_state_changed) {
-		notify_ops->vring_state_changed(dev, base_idx / VIRTIO_QNUM,
-						enable);
+		notify_ops->vring_state_changed(dev, state->index, enable);
 	}
 
-	dev->virtqueue[base_idx + VIRTIO_RXQ]->enabled = enable;
-	dev->virtqueue[base_idx + VIRTIO_TXQ]->enabled = enable;
+	dev->virtqueue[state->index]->enabled = enable;
 
 	return 0;
 }
-- 
1.9.3