Re: [dpdk-dev] [PATCH v3] net/vhost: fix vhost invalid state

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

On 04/12/2018 09:34 AM, Chen, Junjie J wrote:
>>
>>
>>
>> On 04/12/2018 09:21 AM, Tan, Jianfeng wrote:
>>>
>>>
>>> On 4/12/2018 1:02 AM, 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).
>>>>
>>>> Fixes: 30a701a53737 ("net/vhost: fix crash when creating vdev
>>>> dynamically")
>>>>
>>>> Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>
>>>> Tested-by: Jens Freimann <jfreimann@redhat.com>
>>>
>>> Overall, looks great to me except a nit below.
>>>
>>> Reviewed-by: Jianfeng Tan <jianfeng.tan@intel.com>
>>
>> Thanks Jianfeng, I can handle the small change while applying.
>>
>> Can you confirm that it is implied that the queue are already allocated, else we
>> wouldn't find the internal resource and quit earlier (in case of eth_dev_close
>> called twice for example)?
> 
> That is required, otherwise it generate segfault if we close device before queue setup. For example we
> execute following steps in testpmd:
> 1. port attach
> 2. ctrl+D

Thanks for confirming Junjie, I will apply it as is then.

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime

>>
>> Thanks,
>> Maxime
>>
>>>
>>>> ---
>>>> Changes in v3:
>>>> - remove useless log in queue status showing 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 | 59
>>>> +++++++++++++++++++--------------------
>>>>    1 file changed, 29 insertions(+), 30 deletions(-)
>>>>
>>>> diff --git a/drivers/net/vhost/rte_eth_vhost.c
>>>> b/drivers/net/vhost/rte_eth_vhost.c
>>>> index 11b6076..e392d71 100644
>>>> --- a/drivers/net/vhost/rte_eth_vhost.c
>>>> +++ b/drivers/net/vhost/rte_eth_vhost.c
>>>> @@ -528,10 +528,11 @@ 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)
>>>>            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 +608,10 @@ 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
>>>> +620,7 @@ 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 +650,24 @@ 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 +792,7 @@ 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 +832,13 @@
>>>> 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)
>>>
>>> This is implied that rx_queues is already allocated. So I don't think
>>> we need this.
>>>
>>>> +        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);
>>>