Re: [virtio-dev] [PATCH 0/1] Add "Group Identifier" to virtio PCI capabilities.

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

On Fri, Jun 01, 2018 at 01:36:34PM -0700, Siwei Liu wrote:
> On Fri, Jun 1, 2018 at 1:03 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
> > On Fri, Jun 01, 2018 at 12:01:26PM -0500, Venu Busireddy wrote:
> >> On 2018-06-01 18:42:06 +0300, Michael S. Tsirkin wrote:
> >> > On Wed, May 23, 2018 at 11:16:12AM -0400, Venu Busireddy wrote:
> >> > > During live migration involving passthrough devices, the guest needs
> >> > > to know which virtio device will be a fail-over device for a given
> >> > > passthrough device.
> >> > >
> >> > > Extending the virtio specification with a new "Group Identifier"
> >> > > capability allows qemu to set up the grouping at the time the guest
> >> > > is created. The "Group Identifier" can be as simple as a number, or an
> >> > > UUID. The driver can use the group identifier to pair the virtio device
> >> > > with the passthrough device. The passthrough device can contain the
> >> > > group identifier in the PCIe bridge to which it is attached.
> >> > >
> >> > > Venu Busireddy (1):
> >> > >   Add "Group Identifier" to virtio PCI capabilities.
> >> > >
> >> > >  content.tex | 43 +++++++++++++++++++++++++++++++++++++++++++
> >> > >  1 file changed, 43 insertions(+)
> >> >
> >> > Is this a PCI thing, or can this somehow be used with non-PCI
> >>
> >> This is applicable to all virtio PCI devices, but not to non-PCI
> >> devices.
> >>
> >> > devices? If PCI, we can just add a PCI UUID capability to
> >> > virtio without need to worry about the spec.
> >>
> >> What is a "PCI UUID capability?" "PCI Local Bus Specification
> >> Revision 3.0, Appendix H" does not list any such capability.
> >>
> >> Regards,
> >>
> >> Venu
> >
> > Sorry that I'm unclear. What I meant is the
> > PCI Express serial number capability (0003h).
> 
> Then what's on legacy PCI bridge device with i440fx chipset? VPD capability?

Or just limit this to Express.
At this point main benefit of legacy PCI is to support legacy virtio
and that won't support this new feature.

> >
> > --
> > MST
> >
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