Re: [virtio] [OASIS Issue Tracker] Created: (VIRTIO-35) race condition with multi-dword config accesses

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

On Thu, Oct 10, 2013 at 03:53:46PM +0100, Pawel Moll wrote:
> On Thu, 2013-10-10 at 12:26 +0100, Michael S. Tsirkin wrote:
> > I think a transitional device should report version 1.
> > In legacy drivers version is checked before features are probed
> > so as far as I can see there's no way for device to detect a legacy driver and
> > switch that to 1 dynamically.
> > 
> > I'm not saying spec should force anyone to implement
> > transitional devices, but I don't see why it should
> > make this completely impossible.
> > 
> > So I think that a device compliant with the spec can report versions 1 or 2.
> 
> I'll repeat myself. The version register defines the registers layout.
> Different register layout, different version number. And let me put this
> thing clear - you will not convince my otherwise. You can vote me wrong.
> 
> Paweł
> 

Two questions:
- What's wrong with feature bits as a way to
  select a different layout? That's what they were
  designed for.
- So what's the plan for transitional devices?

-- 
MST