[dpdk-dev] [RFC 1/2] vhost: add packed ring support to vring base requests

[Maxime Coquelin]

For consistency with Vhost kernel backend, save the wrap
counter value into bit 31 of num's vring state field.

Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
---
 lib/librte_vhost/vhost_user.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index a2d4c9ffc..31cfdf163 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -648,10 +648,15 @@ static int
 vhost_user_set_vring_base(struct virtio_net *dev,
                          VhostUserMsg *msg)
 {
-       dev->virtqueue[msg->payload.state.index]->last_used_idx  =
-                       msg->payload.state.num;
-       dev->virtqueue[msg->payload.state.index]->last_avail_idx =
-                       msg->payload.state.num;
+       struct vhost_virtqueue *vq = dev->virtqueue[msg->payload.state.index];
+       if (dev->features & (1ULL << VIRTIO_F_RING_PACKED)) {
+               vq->avail_wrap_counter = msg->payload.state.num >> 31;
+               vq->used_wrap_counter = vq->avail_wrap_counter;
+               msg->payload.state.num &= ~(1 << 31);
+       }
+
+       vq->last_used_idx = msg->payload.state.num;
+       vq->last_avail_idx = msg->payload.state.num;
 
        return 0;
 }
@@ -1083,6 +1088,9 @@ vhost_user_get_vring_base(struct virtio_net *dev,
        /* Here we are safe to get the last avail index */
        msg->payload.state.num = vq->last_avail_idx;
 
+       if (dev->features & (1ULL << VIRTIO_F_RING_PACKED))
+               msg->payload.state.num |= vq->avail_wrap_counter << 31;
+
        RTE_LOG(INFO, VHOST_CONFIG,
                "vring base idx:%d file:%d\n", msg->payload.state.index,
                msg->payload.state.num);
-- 
2.17.1