[dpdk-stable] [DPDK] net/virtio-user: fix server mode packed ring

[Xuan Ding <xuan.ding@intel.com>]

This patch fixes the packed ring support for virtio server mode.

Currently, virtio and vhost share memory of vring,
virtio server mode with split ring is already supported by
reading the information of avail ring and used ring directly.

For packed ring, the information of discriptor ring cannot
indicate where is the start when back-end reconnects to front-end.
By resetting Tx and Rx queues, the datapath can continue.

Fixes: bd8f50a45d0f ("net/virtio-user: support server mode")
Cc: stable@dpdk.org

Signed-off-by: Xuan Ding <xuan.ding@intel.com>
---
 drivers/net/virtio/virtio_ethdev.c      | 90 +++++++++++++++++++++++++
 drivers/net/virtio/virtio_ethdev.h      |  2 +
 drivers/net/virtio/virtio_user_ethdev.c |  7 ++
 3 files changed, 99 insertions(+)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index 044eb10a7..d53289327 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -433,6 +433,78 @@ virtio_init_vring(struct virtqueue *vq)
 	virtqueue_disable_intr(vq);
 }
 
+static int
+virtio_user_reset_rx_queues(struct rte_eth_dev *dev, uint16_t queue_idx)
+{
+	uint16_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_RQ_QUEUE_IDX;
+	struct virtio_hw *hw = dev->data->dev_private;
+	struct virtqueue *vq = hw->vqs[vtpci_queue_idx];
+	struct virtnet_rx *rxvq;
+
+	vq->vq_packed.used_wrap_counter = 1;
+	vq->vq_packed.cached_flags = VRING_PACKED_DESC_F_AVAIL;
+	vq->vq_packed.event_flags_shadow = 0;
+	vq->vq_packed.cached_flags |= VRING_DESC_F_WRITE;
+
+	rxvq = &vq->rxq;
+	memset(rxvq->mz->addr, 0, rxvq->mz->len);
+
+	virtio_init_vring(vq);
+
+	return 0;
+}
+
+static int
+virtio_user_reset_tx_queues(struct rte_eth_dev *dev, uint16_t queue_idx)
+{
+	uint8_t vtpci_queue_idx = 2 * queue_idx + VTNET_SQ_TQ_QUEUE_IDX;
+	struct virtio_hw *hw = dev->data->dev_private;
+	struct virtqueue *vq = hw->vqs[vtpci_queue_idx];
+	struct virtnet_tx *txvq;
+	struct vq_desc_extra *dxp;
+	unsigned int vq_size;
+	uint16_t desc_idx;
+
+	vq_size = VTPCI_OPS(hw)->get_queue_num(hw, vtpci_queue_idx);
+
+	vq->vq_packed.used_wrap_counter = 1;
+	vq->vq_packed.cached_flags = VRING_PACKED_DESC_F_AVAIL;
+	vq->vq_packed.event_flags_shadow = 0;
+
+	txvq = &vq->txq;
+	memset(txvq->mz->addr, 0, txvq->mz->len);
+	memset(txvq->virtio_net_hdr_mz->addr, 0,
+		txvq->virtio_net_hdr_mz->len);
+
+	/* Mbuf free for TX queues */
+	for (desc_idx = 0; desc_idx < vq_size; desc_idx++) {
+		dxp = &vq->vq_descx[desc_idx];
+
+		if (dxp->cookie != NULL) {
+			rte_pktmbuf_free(dxp->cookie);
+			dxp->cookie = NULL;
+		}
+	}
+
+	virtio_init_vring(vq);
+
+	return 0;
+}
+
+static int
+virtio_user_reset_queues(struct rte_eth_dev *eth_dev)
+{
+	uint16_t i;
+
+	/* Vring memory free for each Tx queue and Rx queue */
+	for (i = 0; i < eth_dev->data->nb_rx_queues; i++)
+		virtio_user_reset_rx_queues(eth_dev, i);
+	for (i = 0; i < eth_dev->data->nb_rx_queues; i++)
+		virtio_user_reset_tx_queues(eth_dev, i);
+
+	return 0;
+}
+
 static int
 virtio_init_queue(struct rte_eth_dev *dev, uint16_t vtpci_queue_idx)
 {
@@ -1913,6 +1985,8 @@ eth_virtio_dev_init(struct rte_eth_dev *eth_dev)
 			goto err_vtpci_init;
 	}
 
+	rte_spinlock_init(&hw->state_lock);
+
 	/* reset device and negotiate default features */
 	ret = virtio_init_device(eth_dev, VIRTIO_PMD_DEFAULT_GUEST_FEATURES);
 	if (ret < 0)
@@ -2421,6 +2495,22 @@ virtio_dev_vlan_offload_set(struct rte_eth_dev *dev, int mask)
 	return 0;
 }
 
+int
+virtio_user_reset_device(struct rte_eth_dev *eth_dev, struct virtio_hw *hw)
+{
+	/* Waitting for datapath to complete before resetting queues */
+	virtio_dev_pause(eth_dev);
+
+	virtio_user_reset_queues(eth_dev);
+
+	virtio_dev_resume(eth_dev);
+
+	for (uint16_t i = 0; i < hw->max_queue_pairs; i++)
+		virtio_dev_rx_queue_setup_finish(eth_dev, i);
+
+	return 0;
+}
+
 static int
 virtio_dev_info_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info)
 {
diff --git a/drivers/net/virtio/virtio_ethdev.h b/drivers/net/virtio/virtio_ethdev.h
index a10111758..004dfa643 100644
--- a/drivers/net/virtio/virtio_ethdev.h
+++ b/drivers/net/virtio/virtio_ethdev.h
@@ -49,6 +49,8 @@
 
 extern const struct eth_dev_ops virtio_user_secondary_eth_dev_ops;
 
+int virtio_user_reset_device(struct rte_eth_dev *eth_dev, struct virtio_hw *hw);
+
 /*
  * CQ function prototype
  */
diff --git a/drivers/net/virtio/virtio_user_ethdev.c b/drivers/net/virtio/virtio_user_ethdev.c
index 3fc172573..ffb9a5a59 100644
--- a/drivers/net/virtio/virtio_user_ethdev.c
+++ b/drivers/net/virtio/virtio_user_ethdev.c
@@ -31,6 +31,7 @@ virtio_user_server_reconnect(struct virtio_user_dev *dev)
 	int ret;
 	int connectfd;
 	struct rte_eth_dev *eth_dev = &rte_eth_devices[dev->port_id];
+	struct virtio_hw *hw = eth_dev->data->dev_private;
 
 	connectfd = accept(dev->listenfd, NULL, NULL);
 	if (connectfd < 0)
@@ -51,6 +52,12 @@ virtio_user_server_reconnect(struct virtio_user_dev *dev)
 
 	dev->features &= dev->device_features;
 
+	/* For packed virtqueue, resetting queues
+	 * is required in reconnection.
+	 */
+	if (vtpci_packed_queue(hw))
+		virtio_user_reset_device(eth_dev, hw);
+
 	ret = virtio_user_start_device(dev);
 	if (ret < 0)
 		return -1;
-- 
2.17.1