Re: [PATCH 4/4] virtio-net: add linkspeed and duplex settings to virtio-net

[Jason Baron <jbaron@akamai.com>]

On 03/02/2018 02:14 AM, Jason Wang wrote:
> 
> 
> On 2018年03月02日 11:46, Jason Baron wrote:
>> Although linkspeed and duplex can be set in a linux guest via 'ethtool
>> -s',
>> this requires custom ethtool commands for virtio-net by default.
>>
>> Introduce a new feature flag, VIRTIO_NET_F_SPEED_DUPLEX, which allows
>> the hypervisor to export a linkspeed and duplex setting. The user can
>> subsequently overwrite it later if desired via: 'ethtool -s'.
>>
>> Linkspeed and duplex settings can be set as:
>> '-device virtio-net,speed=10000,duplex=full'
> 
> I was thinking whether or not it's better to decide the duplex by the
> type of backends.
> 
> E.g userspace and vhost-kernel implement a in fact half duplex. But dpdk
> implement a full duplex.

Interesting - could this be derived only from the backend 'type'. IE:
NET_CLIENT_DRIVER_TAP, NET_CLIENT_DRIVER_VHOST_USER...


I was also thinking this could be specified as 'duplex=backend', in
addition to the proposed 'duplex=full' or 'duplex=half'?

Thanks,

-Jason

> 
> Thanks
> 
>>
>> where speed is [0...INT_MAX], and duplex is ["half"|"full"].
>>
>> Signed-off-by: Jason Baron<jbaron@akamai.com>
>> Cc: "Michael S. Tsirkin"<mst@redhat.com>
>> Cc: Jason Wang<jasowang@redhat.com>
>> Cc:virtio-dev@lists.oasis-open.org
>> ---
>