Re: [PATCH V2] virtio-net: introduce admin control virtqueue

[Jason Wang <jasowang@redhat.com>]

On 2021/1/29 äå6:57, Cornelia Huck wrote:
> On Thu, 28 Jan 2021 10:58:49 +0800
> Jason Wang <jasowang@redhat.com> wrote:
>
> > On 2021/1/27 äå6:59, Michael S. Tsirkin wrote:
> > > Thus, an idea. How about controlling features instead?
> > >
> > > And with that, the interface becomes generic and applicable
> > > to all devices not just net ...
> >
> > Yes, so I think we probably need more than this e.g I had plan to
> > introduce a general admin virtqueue which could be use to replace the
> > transport specific way to configure/probe virtual devices. I think we
> > can add this new features controlling command via that virtqueue.
> >
> > So if this makes sense. I will drop the trust command in this patch and
> > let admin cvq go first. Then I can post general admin virtqueue patch.
> >
> > Does this make sense?
> So, you'd introduce a generic admin virtqueue and give individual
> device types the possibility to use it for device type specific
> commands?


This is mainly for the trust command. The idea is to have a admin 
virtqueue that is used to manage the features that belongs to a virtual 
device. And in the admin virtqueue, we can introduce a command like:

VIRTIO_ADMIN_CTRL_DEV_FEATURES

that is used to control the features set of a specific virtual device. 
Then there's no need for a specialized trust command in the admin 
control vq for virtio-net.

E.g we can filter out VIRTIO_NET_F_CTRL_MAC_ADDR if we don't want to set 
mac address via control virtqueue, then the virtual device can't see 
this feature via cvq (or admin cvq).

Thanks