Re: [virtio] Feedback: PCI device spec

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

On Tue, Jan 28, 2014 at 04:52:12PM +0100, Paolo Bonzini wrote:
> Il 28/01/2014 15:00, Pawel Moll ha scritto:
> >I had a look at the spec and appendix D. "Class Codes" defines "00h
> >Device was built before Class Code definitions were finalized" and a
> >brief look at Linux kernel shows that it would work. At the same time
> >native KVM tools use "01h Mass storage controller" with
> >subclass/interface "80h 00h Other mass storage controller" which
> >probably makes sense.
> 
> Here is what QEMU uses:
> 
> virtio-9p			??? (0x2)
> virtio-blk			storage/SCSI (0x01/0x00)
> virtio-scsi			storage/SCSI (0x01/0x00)
> virtio-balloon			other (0xff)
> virtio-serial			communication/other (0x07/0x80)
> virtio-net			network/Ethernet (0x02/0x00)
> virtio-rng			other (0xff)
> 
> The choice for virtio-blk is because Microsoft Windows logo program
> has a rather stupid requirement that devices must use 0x01/0x00.  It
> would probably be just as stupid to put 0x01/00 in the spec, but
> it's an issue that vendors will face.
> 
> Perhaps we can specify 0x01 for virtio-blk and 0x07 for
> virtio-serial, and leave the choice of subclass to the
> implementation?
> 
> Paolo

If it's not a virtio requirement, I'm not sure we should put this
in spec - also logo requirements change.
I think it's best for drivers to ignore class, if we document
it this invites drivers to check class.

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