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

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

On 13 Nov 2019, at 2:14, Zhang, Xiao wrote:

>> -----Original Message-----
>> From: Eelco Chaudron [mailto:echaudro@redhat.com]
>> Sent: Tuesday, November 12, 2019 7:09 PM
>> To: Zhang, Xiao <xiao.zhang@intel.com>
>> Cc: Zhang, Qi Z <qi.z.zhang@intel.com>; dev@dpdk.org; Xing, Beilei
>> <beilei.xing@intel.com>
>> Subject: Re: [dpdk-dev] [PATCH] net/i40e: force promiscuous state 
>> after VF
>> reset
>>
>>
>>
>> On 12 Nov 2019, at 1:52, Zhang, Xiao wrote:
>>
>>> Hi Eelco,
>>>
>>> Seems you missed this mail.
>>
>> Not sure why I missed this email, as it does not show up in my email 
>> client :( See
>> below…
>>
>>
>> <SNIP>
>>>>>>>> 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?
>>>>>>
>>>>>> Yes, promisc_unicast_enabled flag is not cleared during vf reset
>>>>>> because fail to disable promiscuous mode, So I think we need to
>>>>>> root
>>>>>> cause why fail to  disable promiscuous mode first.
>>>>>> This patch looks like a workaround but not a fix.
>>>>>>
>>>>>
>>>>> This was debugged together with Xiao and from what I understand is
>>>>> that DPDK fails to reset promiscuous mode in hardware as PF and VF
>>>>> operations are not synced between kernel and DPDK.
>>>>>
>>>>> Xiao told me this could not be fixed in another way, Xiao can you
>>>>> comment?
>>>>>
>>>>
>>>> Checked again, the root cause is not synced issue between kernel 
>>>> and
>>>> DPDK
>>>> during reset.
>>
>> What is the root cause, so I can update the patch description for the
>> next revision.
>
> Kernel PF do reset once VF mac changed and send reset event to VF,
> VF do reset once received even if reset task not done by PF, so admin 
> q message will not get response.

Thanks, added this to the v2 commit message.

>>
>>>> Suggest to remove the checking and setting of 
>>>> promisc_unicast_enabled
>>>> flag,
>>>> since this flag is only used when enable/disable promiscuous mode.
>>>> Considering the un-synced issue, it will be more clean if remove 
>>>> the
>>>> flag.
>>>> Also same with flag promisc_multicast_enabled.
>>
>> So if I understand it correctly remove the following code:
>>
>> 2203  	/* If enabled, just return */
>> 2204  	if (vf->promisc_multicast_enabled)
>> 2205  		return 0;
>>
>> and
>>
>> 2222  	/* If enabled, just return */
>> 2223  	if (!vf->promisc_multicast_enabled)
>> 2224  		return 0;
>>
>> Or to remove the flags from the i40e_vf structure (and relative  
>> code):
>>
>> 1051  	bool promisc_unicast_enabled;
>> 1052  	bool promisc_multicast_enabled;
>>
>> Let me know and I craft up a patch…
>
> You can remove promisc_unicast_enabled/promisc_multicast_enabled and 
> related code.

Removing the flags did not work, as they are needed for programming one 
or the other, so I kept them.
In the end, I removed the “If enabled” checks above, see the v2 
patch with the name
“[PATCH v2] net/i40e: always re-program promiscuous mode on VF 
interface”