Re: [dpdk-dev] [PATCH v2] net/vhost: fix vhost invalid state

["Tan, Jianfeng" <jianfeng.tan@intel.com>]

On 4/11/2018 4:35 PM, Chen, Junjie J wrote:
>>
>> On 4/11/2018 6:53 PM, Junjie Chen wrote:
>>> dev_start sets *dev_attached* after setup queues, this sets device to
>>> invalid state since no frontend is attached. Also destroy_device set
>>> *started* to zero which makes *allow_queuing* always zero until
>>> dev_start get called again. Actually, we should not determine queues
>>> existence by
>>> *dev_attached* but by queues pointers or other separated variable(s).
>> I see two issues from your description:
>>
>> - We shall fix the wrong use of dev_attached by commit 30a701a53737.
>> - The allow_queuing is not set correctly. But I doubt if it's a real issue, as we do
>> update the queue status in dev_start(), dev_stop(), and new_device(). Can you
>> explain more?
> The started is set to 0 in destroy_device in 30a701a53737 commit, so allow_queuing is always
> set to 0 once update_queuing_status get called. We have to use "port start" to reset to 1.

OK, that means it is also due to the wrong use of dev_attached?

>>> Fixes: 30a701a53737 ("net/vhost: fix crash when creating vdev
>>> dynamically")
>>>
>>> Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>
>>> ---
>>> Changes in v2:
>>> - use started to determine vhost queues readiness
>>> - revert setting started to zero in destroy_device
>>>    drivers/net/vhost/rte_eth_vhost.c | 61
>> ++++++++++++++++++++-------------------
>>>    1 file changed, 31 insertions(+), 30 deletions(-)
>>>
>>> diff --git a/drivers/net/vhost/rte_eth_vhost.c
>> b/drivers/net/vhost/rte_eth_vhost.c
>>> index 11b6076..ff462b3 100644
>>> --- a/drivers/net/vhost/rte_eth_vhost.c
>>> +++ b/drivers/net/vhost/rte_eth_vhost.c
>>> @@ -528,10 +528,13 @@ update_queuing_status(struct rte_eth_dev *dev)
>>>    	unsigned int i;
>>>    	int allow_queuing = 1;
>>>
>>> -	if (rte_atomic32_read(&internal->dev_attached) == 0)
>>> +	if (!dev->data->rx_queues || !dev->data->tx_queues) {
>>> +		RTE_LOG(ERR, PMD, "RX/TX queues not exist yet\n");
>> Even it's not introduced in this patch, but I think we shall not report
>> error log here.
> if you attach one port with "port attach" (no vhost queue setup yet), and then execute
> "port stop", the queue status is not exist yet, right?

My point is that we allow a dev is not started but attached, so it's not 
an error, and we shall not print error log.

>>>    		return;
>>> +	}
>>>
>>> -	if (rte_atomic32_read(&internal->started) == 0)
>>> +	if (rte_atomic32_read(&internal->started) == 0 ||
>>> +	    rte_atomic32_read(&internal->dev_attached) == 0)
>>>    		allow_queuing = 0;
>>>
>>>    	/* Wait until rx/tx_pkt_burst stops accessing vhost device */
>>> @@ -607,13 +610,10 @@ new_device(int vid)
>>>    #endif
>>>
>>>    	internal->vid = vid;
>>> -	if (eth_dev->data->rx_queues && eth_dev->data->tx_queues) {
>>> +	if (rte_atomic32_read(&internal->started) == 1)
>>>    		queue_setup(eth_dev, internal);
>>> -		rte_atomic32_set(&internal->dev_attached, 1);
>>> -	} else {
>>> -		RTE_LOG(INFO, PMD, "RX/TX queues have not setup yet\n");
>>> -		rte_atomic32_set(&internal->dev_attached, 0);
>>> -	}
>>> +	else
>>> +		RTE_LOG(INFO, PMD, "RX/TX queues not exist yet\n");
>>>
>>>    	for (i = 0; i < rte_vhost_get_vring_num(vid); i++)
>>>    		rte_vhost_enable_guest_notification(vid, i, 0);
>>> @@ -622,6 +622,7 @@ new_device(int vid)
>>>
>>>    	eth_dev->data->dev_link.link_status = ETH_LINK_UP;
>>>
>>> +	rte_atomic32_set(&internal->dev_attached, 1);
>>>    	update_queuing_status(eth_dev);
>>>
>>>    	RTE_LOG(INFO, PMD, "Vhost device %d created\n", vid);
>>> @@ -651,23 +652,24 @@ destroy_device(int vid)
>>>    	eth_dev = list->eth_dev;
>>>    	internal = eth_dev->data->dev_private;
>>>
>>> -	rte_atomic32_set(&internal->started, 0);
>>> -	update_queuing_status(eth_dev);
>>>    	rte_atomic32_set(&internal->dev_attached, 0);
>>> +	update_queuing_status(eth_dev);
>>>
>>>    	eth_dev->data->dev_link.link_status = ETH_LINK_DOWN;
>>>
>>> -	for (i = 0; i < eth_dev->data->nb_rx_queues; i++) {
>>> -		vq = eth_dev->data->rx_queues[i];
>>> -		if (vq == NULL)
>>> -			continue;
>>> -		vq->vid = -1;
>>> -	}
>>> -	for (i = 0; i < eth_dev->data->nb_tx_queues; i++) {
>>> -		vq = eth_dev->data->tx_queues[i];
>>> -		if (vq == NULL)
>>> -			continue;
>>> -		vq->vid = -1;
>>> +	if (eth_dev->data->rx_queues && eth_dev->data->tx_queues) {
>>> +		for (i = 0; i < eth_dev->data->nb_rx_queues; i++) {
>>> +			vq = eth_dev->data->rx_queues[i];
>>> +			if (!vq)
>>> +				continue;
>>> +			vq->vid = -1;
>>> +		}
>>> +		for (i = 0; i < eth_dev->data->nb_tx_queues; i++) {
>>> +			vq = eth_dev->data->tx_queues[i];
>>> +			if (!vq)
>>> +				continue;
>>> +			vq->vid = -1;
>>> +		}
>>>    	}
>>>
>>>    	state = vring_states[eth_dev->data->port_id];
>>> @@ -792,11 +794,7 @@ eth_dev_start(struct rte_eth_dev *eth_dev)
>>>    {
>>>    	struct pmd_internal *internal = eth_dev->data->dev_private;
>>>
>>> -	if (unlikely(rte_atomic32_read(&internal->dev_attached) == 0)) {
>>> -		queue_setup(eth_dev, internal);
>>> -		rte_atomic32_set(&internal->dev_attached, 1);
>>> -	}
>>> -
>>> +	queue_setup(eth_dev, internal);
>>>    	rte_atomic32_set(&internal->started, 1);
>>>    	update_queuing_status(eth_dev);
>>>
>>> @@ -836,10 +834,13 @@ eth_dev_close(struct rte_eth_dev *dev)
>>>    	pthread_mutex_unlock(&internal_list_lock);
>>>    	rte_free(list);
>>>
>>> -	for (i = 0; i < dev->data->nb_rx_queues; i++)
>>> -		rte_free(dev->data->rx_queues[i]);
>>> -	for (i = 0; i < dev->data->nb_tx_queues; i++)
>>> -		rte_free(dev->data->tx_queues[i]);
>>> +	if (dev->data->rx_queues)
>>> +		for (i = 0; i < dev->data->nb_rx_queues; i++)
>>> +			rte_free(dev->data->rx_queues[i]);
>>> +
>>> +	if (dev->data->tx_queues)
>>> +		for (i = 0; i < dev->data->nb_tx_queues; i++)
>>> +			rte_free(dev->data->tx_queues[i]);
>>>
>>>    	rte_free(dev->data->mac_addrs);
>>>    	free(internal->dev_name);