Re: [dpdk-dev] [PATCH] net/virtio-user: add unsupported features mask

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

On 06/26/2018 11:02 AM, Liu, Yong wrote:
> 
> 
>> -----Original Message-----
>> From: Maxime Coquelin [mailto:maxime.coquelin@redhat.com]
>> Sent: Tuesday, June 26, 2018 4:08 PM
>> To: Liu, Yong <yong.liu@intel.com>; Bie, Tiwei <tiwei.bie@intel.com>
>> Cc: Wang, Zhihong <zhihong.wang@intel.com>; dev@dpdk.org
>> Subject: Re: [PATCH] net/virtio-user: add unsupported features mask
>>
>>
>>
>> On 06/25/2018 03:10 PM, Marvin Liu wrote:
>>> This patch introduces unsupported features mask for virtio-user device.
>>> For virtio-user server mode, when reconnecting virtio-user will
>>> retrieve vhost devcie features as base and then unmask unsupported
>> s/devcie/device/
>>> features.
>>
>> I am not sure to understand why you are doing it like this.
>>
>> Shouldn't you just:
>>    1. Don't advertise features you don't want to support
>>    2. In server mode, save the negotiated features, and re-use it when
>>       reconnect happens?
>>
> Maxime,
> I think our vhost reconnect design is following qemu vhost-user server mode. Virtio-user will try to support connected vhost device.
> So device_features of virtio user just retrieve from vhost device.
> And in server mode, we have recorded previous feature bits and used it for later negotiation. But virtio user device_features which may has changed by vdev parameters. This mask will guaranty device_features correct.

Ok, get it now, thanks for the clarification.

Please reword the variable name as I proposed, and pick this patch
directly in your in_order series.

With name change, feel free to add:
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime

> Thanks,
> Marvin
> 
>> Also, I find "unmask" a bit misleading, why not something like "unsupp"
>> or "unsupported"?
>>
>> Thanks,
>> Maxime