Re: [dpdk-dev] [PATCH] net/virtio: fix crash when device reconnecting

["Liu, Yong" <yong.liu@intel.com>]

> -----Original Message-----
> From: Ye, Xiaolong <xiaolong.ye@intel.com>
> Sent: Wednesday, April 15, 2020 3:24 PM
> To: Liu, Yong <yong.liu@intel.com>
> Cc: maxime.coquelin@redhat.com; Wang, Zhihong
> <zhihong.wang@intel.com>; dev@dpdk.org; Ding, Xuan
> <xuan.ding@intel.com>
> Subject: Re: [PATCH] net/virtio: fix crash when device reconnecting
> 
> Hi, Marvin
> 
> On 04/14, Marvin Liu wrote:
> >When doing virtio device initialization, virtqueues will be reset in
> >server mode if ring type is packed. This will cause issue because queues
> >have been freed in the beginning of device initialization.
> >
> >Fix this issue by splitting device initial process and device reinit
> >process. Virt queues won't be freed or realloc in reinit process. Also
> >moved virtio device initialization from configuration to start stage,
> >which can reduce number of reinitialization times.
> >
> >Fixes: 6ebbf4109f35 ("net/virtio-user: fix packed ring server mode")
> 
> I think it also needs to cc stable.
> 

Hi Xiaolong,
Packed ring server mode fix was merged in 20.02 release. So there's no stable branch for it. 

Thanks,
Marvin

> >
> >Signed-off-by: Marvin Liu <yong.liu@intel.com>
> >
> >diff --git a/drivers/net/virtio/virtio_ethdev.c
> b/drivers/net/virtio/virtio_ethdev.c
> >index 21570e5cf..8c84bfe91 100644
> >--- a/drivers/net/virtio/virtio_ethdev.c
> >+++ b/drivers/net/virtio/virtio_ethdev.c
> >@@ -1670,7 +1670,9 @@ virtio_configure_intr(struct rte_eth_dev *dev)
> >
> > /* reset device and renegotiate features if needed */
> > static int
> >-virtio_init_device(struct rte_eth_dev *eth_dev, uint64_t req_features)
> >+virtio_init_device(struct rte_eth_dev *eth_dev,
> >+		   uint64_t req_features,
> >+		   bool reinit)
> > {
> > 	struct virtio_hw *hw = eth_dev->data->dev_private;
> > 	struct virtio_net_config *config;
> >@@ -1681,7 +1683,7 @@ virtio_init_device(struct rte_eth_dev *eth_dev,
> uint64_t req_features)
> > 	/* Reset the device although not necessary at startup */
> > 	vtpci_reset(hw);
> >
> >-	if (hw->vqs) {
> >+	if (hw->vqs && !reinit) {
> > 		virtio_dev_free_mbufs(eth_dev);
> > 		virtio_free_queues(hw);
> > 	}
> >@@ -1794,9 +1796,11 @@ virtio_init_device(struct rte_eth_dev *eth_dev,
> uint64_t req_features)
> > 			VLAN_TAG_LEN - hw->vtnet_hdr_size;
> > 	}
> >
> >-	ret = virtio_alloc_queues(eth_dev);
> >-	if (ret < 0)
> >-		return ret;
> >+	if (!reinit) {
> >+		ret = virtio_alloc_queues(eth_dev);
> >+		if (ret < 0)
> >+			return ret;
> >+	}
> >
> > 	if (eth_dev->data->dev_conf.intr_conf.rxq) {
> > 		if (virtio_configure_intr(eth_dev) < 0) {
> >@@ -1925,7 +1929,8 @@ eth_virtio_dev_init(struct rte_eth_dev *eth_dev)
> > 	rte_spinlock_init(&hw->state_lock);
> >
> > 	/* reset device and negotiate default features */
> >-	ret = virtio_init_device(eth_dev,
> VIRTIO_PMD_DEFAULT_GUEST_FEATURES);
> >+	ret = virtio_init_device(eth_dev,
> VIRTIO_PMD_DEFAULT_GUEST_FEATURES,
> >+			false);
> > 	if (ret < 0)
> > 		goto err_virtio_init;
> >
> >@@ -2091,12 +2096,6 @@ virtio_dev_configure(struct rte_eth_dev *dev)
> > 		return -EINVAL;
> > 	}
> >
> >-	if (dev->data->dev_conf.intr_conf.rxq) {
> >-		ret = virtio_init_device(dev, hw->req_guest_features);
> >-		if (ret < 0)
> >-			return ret;
> >-	}
> >-
> > 	if (rxmode->max_rx_pkt_len > hw->max_mtu + ether_hdr_len)
> > 		req_features &= ~(1ULL << VIRTIO_NET_F_MTU);
> >
> >@@ -2120,7 +2119,7 @@ virtio_dev_configure(struct rte_eth_dev *dev)
> >
> > 	/* if request features changed, reinit the device */
> > 	if (req_features != hw->req_guest_features) {
> >-		ret = virtio_init_device(dev, req_features);
> >+		ret = virtio_negotiate_features(hw, req_features);
> 
> Why do we need to change virtio_init_device to virtio_negotiate_features
> here?
> 
> Thanks,
> Xiaolong
> 
> > 		if (ret < 0)
> > 			return ret;
> > 	}
> >@@ -2235,6 +2234,11 @@ virtio_dev_start(struct rte_eth_dev *dev)
> > 	struct virtio_hw *hw = dev->data->dev_private;
> > 	int ret;
> >
> >+	/* reinit the device */
> >+	ret = virtio_init_device(dev, hw->req_guest_features, true);
> >+	if (ret < 0)
> >+		return ret;
> >+
> > 	/* Finish the initialization of the queues */
> > 	for (i = 0; i < dev->data->nb_rx_queues; i++) {
> > 		ret = virtio_dev_rx_queue_setup_finish(dev, i);
> >--
> >2.17.1
> >