Re: [dpdk-dev] [PATCH] net/i40e: force promiscuous state after VF reset

["Eelco Chaudron" <echaudro@redhat.com>]

On 29 Oct 2019, at 8:39, Zhang, Xiao wrote:

>> -----Original Message-----
>> From: Eelco Chaudron <echaudro@redhat.com>
>> Sent: Friday, October 25, 2019 5:24 PM
>> To: Xing, Beilei <beilei.xing@intel.com>; Zhang, Xiao 
>> <xiao.zhang@intel.com>
>> Cc: Zhang, Qi Z <qi.z.zhang@intel.com>; dev@dpdk.org
>> Subject: Re: [dpdk-dev] [PATCH] net/i40e: force promiscuous state 
>> after VF
>> reset
>>
>>
>>
>> On 17 Oct 2019, at 8:34, Xing, Beilei wrote:
>>
>>>> On 17 Sep 2019, at 9:40, Eelco Chaudron wrote:
>>>>
>>>>> Even though the device reset is successful, disabling promiscuous
>>>>> mode might not always succeed, causing enabling it after reset to
>>>>> fail.
>>>>> This would happen when the kernel driver requires a reset of the 
>>>>> VF.
>>>>>
>>>>> This patch resets the internal state, so next time promiscuous 
>>>>> mode
>>>>> is configured it will be enabled.
>>>>>
>>>>> Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
>>>>> ---
>>>>>  drivers/net/i40e/i40e_ethdev_vf.c | 10 ++++++++++
>>>>>  1 file changed, 10 insertions(+)
>>>>>
>>>>> diff --git a/drivers/net/i40e/i40e_ethdev_vf.c
>>>>> b/drivers/net/i40e/i40e_ethdev_vf.c
>>>>> index 551f6fa..e0f99a4 100644
>>>>> --- a/drivers/net/i40e/i40e_ethdev_vf.c
>>>>> +++ b/drivers/net/i40e/i40e_ethdev_vf.c
>>>>> @@ -2276,11 +2276,21 @@ static int eth_i40evf_pci_remove(struct
>>>>> rte_pci_device *pci_dev)  i40evf_dev_reset(struct rte_eth_dev 
>>>>> *dev)
>>>>> {
>>>>>  	int ret;
>>>>> +	struct i40e_vf *vf =
>>>>> I40EVF_DEV_PRIVATE_TO_VF(dev->data->dev_private);
>>>>>
>>>>>  	ret = i40evf_dev_uninit(dev);
>>>>>  	if (ret)
>>>>>  		return ret;
>>>>>
>>>>> +	/*
>>>>> +	 * Even though the device reset is successful disabling
>>>>> promiscuous
>>>>> +	 * mode might not always succeed, causing enabling it after 
>>>>> reset
>>>>> to
>>>
>>> I think we need to root cause why fail to disable promiscuous mode 
>>> and
>>> try to fix it first.
>>
>> I’ve copied in Xiao who helped me identify the issue in your 
>> driver.
>>
>> The issue is because the change from kernel pf was not synced to DPDK 
>> vf during
>> the closing period of reset, so we get this failure. Xiao can you add 
>> more details?
>>
>
> The root cause is when kernel pf generate DPDK vf reset event, the 
> flag
> vf->promisc_unicast_enabled will not be cleared but promiscuous mode 
> is
> disabled. When trying to enable promiscuous mode next time by calling
> i40evf_dev_promiscuous_enable won't work because it will check the
> vf->promisc_unicast_enabled flag first.
>
> static int
> i40evf_dev_promiscuous_enable(struct rte_eth_dev *dev)
> {
> ...
>     /* If enabled, just return */
>     if (vf->promisc_unicast_enabled)
>         return 0;
> ...
> }
>
> Hi Eelco,
>
> I think you may need add more detailed message in the commit log or 
> comments.

My interpretation of the request was that Beilei wanted to know why 
disabling promiscuous mode in HW was failing. Beilei can you comment, is 
the additional description from Xiao enough?

>>
>>>>> +	 * fail. This would happen when the kernel driver requires a 
>>>>> reset
>>>>> +	 * of the VF.
>>>>> +	 */
>>>>> +	if (rte_eal_process_type() == RTE_PROC_PRIMARY)
>>>>> +		vf->promisc_unicast_enabled = FALSE;
>>>>> +
>>>>>  	ret = i40evf_dev_init(dev);
>>>>>
>>>>>  	return ret;
>>>>> --
>>>>> 1.8.3.1