[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, the back-end can
directly read the status of discriptors from avail-ring and used-ring
when enable server mode with split ring. Therefore, the datapath can
continue.

But for packed ring, it is hard to obtain the status of discriptors just
from descriptor ring when back-end reconnects to front-end. By resetting
Tx and Rx queues, the datapath can restart from the beginning.

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      | 96 +++++++++++++++++++++++++
 drivers/net/virtio/virtio_ethdev.h      |  3 +
 drivers/net/virtio/virtio_user_ethdev.c |  7 ++
 3 files changed, 106 insertions(+)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index 044eb10a7..3dd3b7718 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -433,6 +433,77 @@ 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);
+
+	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 reset 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 +1984,8 @@ 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 +2494,29 @@ 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)
+{
+	hw->started = 0;
+	/*
+	 * Waitting for datapath to complete before resetting queues.
+	 * 1 ms should be enough for the ongoing Tx/Rx function to finish.
+	 */
+	rte_delay_ms(1);
+
+	/* Add lock to avoid queue contention */
+	rte_spinlock_lock(&hw->state_lock);
+
+	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..72e9e3ff8 100644
--- a/drivers/net/virtio/virtio_ethdev.h
+++ b/drivers/net/virtio/virtio_ethdev.h
@@ -49,6 +49,9 @@
 
 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..d3fbf2c5f 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 ring, 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