Re: [virtio-dev] Re: [PATCH v6 4/4] transport-pci: Introduce group legacy group member config region access

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Jun 21, 2023 at 01:09:40AM +0000, Parav Pandit wrote:
> 
> 
> > From: Michael S. Tsirkin <mst@redhat.com>
> > Sent: Tuesday, June 20, 2023 6:22 AM
> > 
> > On Tue, Jun 20, 2023 at 12:14:16AM +0000, Parav Pandit wrote:
> > >
> > >
> > > > From: virtio-dev@lists.oasis-open.org
> > > > <virtio-dev@lists.oasis-open.org> On Behalf Of Michael S. Tsirkin
> > > > Sent: Monday, June 19, 2023 1:46 PM
> > >
> > > > These devices have a legacy interface yes?
> > > Yes. partially.
> > >
> > > > So they should be transitional to avoid breaking assumption.
> > > >
> > > >
> > > > But they are not *exactly*
> > > > in that they don't have a transitional device ID.
> > > >
> > > Right. They do not have transitional device ID.
> > 
> > I was trying to think whether we need a conformance statement stating so. I
> > guess this is up to the device?
> > Then let's make it clear. Something like:
> > 	For the SR-IOV group type,
> > 	the owner device supporting legacy configuration access commands
> > 	[assuming this is the term - do we define it somewhere? or just
> > 	list the commands]
> This term is largely defined as section name currently.

Right. A sentence saying "the following legacy configuration access
commands allow access to the legacy interface of a member device through
the owner device ..."  at the beginning of the section might be a good idea.

> > 	MAY follow the rules for the PCI Device ID, Revision ID
> > 	and Subsystem Device ID for the non-transitional devices
> > 	documented in
> > 	{Virtio Transport Options / Virtio Over PCI Bus / PCI Device Discovery}
> > 
> > or do you want to make it a SHOULD?
> >
> SHOULD seems fine to me as one cannot build PCI VF hw practically with IOBAR anyway.
> So better to extended above line as,
> 
> For the SR-IOV group type, the owner device ... and member device SHOULD fllow the rules for...


ok

> > 
> > > > At least the device id section needs extra text then to explain this?
> > > >
> > > We don't modify any of the transitional device attributes.
> > > In respective conformance section, it is described what requirements of
> > legacy interface to follow.
> > > > Or do you just want to make them have transitional ID?
> > > Don't want to do that.
> > > Non transitional device id with the extension is just fine.