Re: [virtio-dev] Re: [virtio] [PATCH] pci: strengthen requirement of the correct subsystem id

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

On Mon, Nov 25, 2019 at 11:14:20AM +0100, Cornelia Huck wrote:
> On Mon, 25 Nov 2019 03:22:13 -0500
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> 
> > On Mon, Nov 25, 2019 at 07:41:09AM +0100, Jan Kiszka wrote:
> > > On 28.10.19 17:12, Michael S. Tsirkin wrote:  
> > > > If a hardware implementation of virtio does not have
> > > > the correct subsystem id, then drivers can't report
> > > > ir properly, or detect and work around bugs.  
> > > 
> > > s/ir/it.
> > > 
> > > Jan
> > >   
> > > > Change the requirement from MAY to SHOULD.
> > > > 
> > > > We can't make it a MUST since we did not require this
> > > > historically.
> > > > 
> > > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>  
> > 
> > 
> > One thing I noticed is that for transitional devices, windows drivers
> > bind to a specific vendor id. I guess we need to make this
> > SHOULD for non-transitional only?
> 
> So, they have different binding behaviour for transitional vs
> non-transitional devices? Or transitional vs non-transitional drivers?

Transitional vs non-transitional have different IDs, sure.
That's in the spec.

> > 
> > 
> > > > ---
> > > >   content.tex | 2 +-
> > > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > > > 
> > > > diff --git a/content.tex b/content.tex
> > > > index 4bcb728..8f1518c 100644
> > > > --- a/content.tex
> > > > +++ b/content.tex
> > > > @@ -562,7 +562,7 @@ \subsection{PCI Device Discovery}\label{sec:Virtio Transport Options / Virtio Ov
> > > >   For example, the network card device with the Virtio Device ID 1
> > > >   has the PCI Device ID 0x1041 or the Transitional PCI Device ID 0x1000.
> > > > -The PCI Subsystem Vendor ID and the PCI Subsystem Device ID MAY reflect
> > > > +The PCI Subsystem Vendor ID and the PCI Subsystem Device ID SHOULD reflect
> > > >   the PCI Vendor and Device ID of the environment (for informational purposes by the driver).
> > > >   Non-transitional devices SHOULD have a PCI Device ID in the range
> 
> 
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