Re: [PATCH 2/3] vdpa: load vlan configuration at NIC startup

[Michael S. Tsirkin]

On Wed, Sep 21, 2022 at 04:00:58PM -0700, Si-Wei Liu wrote:
> > > >    The spec doesn't explicitly say anything about that
> > > > as far as I see.
> > > Here the spec is totally ruled by the (software artifact of)
> > > implementation rather than what a real device is expected to work with
> > > VLAN rx filters. Are we sure we'd stick to this flawed device
> > > implementation? The guest driver seems to be agnostic with this broken
> > > spec behavior so far, and I am afraid it's an overkill to add another
> > > feature bit or ctrl command to VLAN filter in clean way.
> > > 
> > I agree with all of the above. So, double checking, all vlan should be
> > allowed by default at device start?
> That is true only when VIRTIO_NET_F_CTRL_VLAN is not negotiated. If the
> guest already negotiated VIRTIO_NET_F_CTRL_VLAN before being migrated,
> device should resume with all VLANs filtered/disallowed.
> 
> >   Maybe the spec needs to be more
> > clear in that regard?
> Yes, I think this is crucial. Otherwise we can't get consistent behavior,
> either from software to vDPA, or cross various vDPA vendors.

OK. Can you open a github issue for the spec? We'll try to address.
Also, is it ok if we make it a SHOULD, i.e. best effort filtering?

-- 
MST