[dpdk-dev] [PATCH v3 1/2] vhost: add packed ring support to vring base requests

[Maxime Coquelin <maxime.coquelin@redhat.com>]

For packed ring layout, we need save and restore avail and
used indexes, and their wrap counter values.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 lib/librte_vhost/vhost_user.c | 41 ++++++++++++++++++++++++++++++-----
 1 file changed, 35 insertions(+), 6 deletions(-)

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 508228a3c..ff80bef8e 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -696,10 +696,24 @@ vhost_user_set_vring_base(struct virtio_net **pdev,
 			int main_fd __rte_unused)
 {
 	struct virtio_net *dev = *pdev;
-	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];
+	uint64_t val = msg->payload.state.num;
+
+	if (vq_is_packed(dev)) {
+		/*
+		 * Bit[0:14]: avail index
+		 * Bit[15]: avail wrap counter
+		 * Bit[16:30]: used index
+		 * Bit[31]: used wrap counter
+		 */
+		vq->last_avail_idx = val & 0x7fff;
+		vq->avail_wrap_counter = (val & (0x1 << 15)) >> 15;
+		vq->last_used_idx = (val & (0x7fff << 16)) >> 16;
+		vq->used_wrap_counter = (val & (0x1 << 31)) >> 31;
+	} else {
+		vq->last_used_idx = msg->payload.state.num;
+		vq->last_avail_idx = msg->payload.state.num;
+	}
 
 	return VH_RESULT_OK;
 }
@@ -1208,6 +1222,7 @@ vhost_user_get_vring_base(struct virtio_net **pdev,
 {
 	struct virtio_net *dev = *pdev;
 	struct vhost_virtqueue *vq = dev->virtqueue[msg->payload.state.index];
+	uint64_t val;
 
 	/* We have to stop the queue (virtio) if it is running. */
 	vhost_destroy_device_notify(dev);
@@ -1215,8 +1230,22 @@ vhost_user_get_vring_base(struct virtio_net **pdev,
 	dev->flags &= ~VIRTIO_DEV_READY;
 	dev->flags &= ~VIRTIO_DEV_VDPA_CONFIGURED;
 
-	/* Here we are safe to get the last avail index */
-	msg->payload.state.num = vq->last_avail_idx;
+	/* Here we are safe to get the indexes */
+	if (vq_is_packed(dev)) {
+		/*
+		 * Bit[0:14]: avail index
+		 * Bit[15]: avail wrap counter
+		 * Bit[16:30]: used index
+		 * Bit[31]: used wrap counter
+		 */
+		val = vq->last_avail_idx & 0x7fff;
+		val |= vq->avail_wrap_counter << 15;
+		val |= (vq->last_used_idx & 0x7fff) << 16;
+		val |= vq->used_wrap_counter << 31;
+		msg->payload.state.num = val;
+	} else {
+		msg->payload.state.num = vq->last_avail_idx;
+	}
 
 	RTE_LOG(INFO, VHOST_CONFIG,
 		"vring base idx:%d file:%d\n", msg->payload.state.index,
-- 
2.17.1