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Date: Wed, 17 Jun 2009 12:51:02 +0100
From: Jamie Lokier <jamie@shareable.org>
Subject: Re: Configuration vs. compat hints [was Re: [Qemu-devel] [PATCHv3
	03/13] qemu: add routines to manage PCI capabilities]
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To: Avi Kivity <avi@redhat.com>
Cc: Carsten Otte <cotte@de.ibm.com>, Rusty Russell <rusty@rustcorp.com.au>, kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>, Glauber Costa <glommer@redhat.com>, dlaor@redhat.com, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, Blue Swirl <blauwirbel@gmail.com>, Christian Borntraeger <borntraeger@de.ibm.com>, Paul Brook <paul@codesourcery.com>, Mark McLoughlin <markmc@redhat.com>

Avi Kivity wrote:
> On 06/16/2009 09:32 PM, Jamie Lokier wrote:
> >Avi Kivity wrote:
> >   
> >>Another issue is enumeration.  Guests will present their devices in the
> >>order they find them on the pci bus (of course enumeration is guest
> >>specific).  So if I have 2 virtio controllers the only way I can
> >>distinguish between them is using their pci slots.
> >
> >virtio controllers really should have a user-suppliable string or UUID
> >to identify them to the guest.  Don't they?
> 
> virtio controllers don't exist.  When they do, they may have a UUID or 
> not, but in either case guest infrastructure is in place for reporting 
> the PCI slot, not the UUID.
> 
> virtio disks do have a UUID.  I don't think older versions of Windows 
> will use it though, so if you reorder your slots you'll see your drive 
> letters change.  Same with Linux if you don't use udev by-uuid rules.

I guess I meant virtio disks, so that's ok.

-- Jamie