From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mark McLoughlin <markmc@redhat.com>
Subject: Re: Configuration vs. compat hints [was Re: [Qemu-devel] [PATCHv3
 03/13] qemu: add routines to manage PCI capabilities]
Date: Fri, 12 Jun 2009 16:53:27 +0100
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Cc: Jamie Lokier <jamie@shareable.org>,
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	Carsten Otte <cotte@de.ibm.com>, kvm@vger.kernel.org,
	Glauber Costa <glommer@redhat.com>,
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	Blue Swirl <blauwirbel@gmail.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Paul Brook <paul@codesourcery.com>, Avi Kivity <avi@redhat.com>
To: Anthony Liguori <anthony@codemonkey.ws>
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On Fri, 2009-06-12 at 09:55 -0500, Anthony Liguori wrote:
> Mark McLoughlin wrote:
> > On Wed, 2009-06-10 at 20:27 +0100, Jamie Lokier wrote:
> >   
> > = Solution - Separate configuration from compat hints =
> >
> > As I suggested before:
> >
> >   - Allow the VM manager to dump compat hints; this would be an opaque 
> >     file format, more like the savevm format than a config file
> >   
> 
> How is compat hints different from a device tree?
> 
> In my mind, that's what compat hints is.  I don't see another sane way 
> to implement it.

A device tree with a different purpose than a config file.

In its simplest form it could be a device tree with a version number for
each device[1]. 

The other obvious piece to add to it would be PCI addresses, so that
even if you remove a device, the addresses assigned to existing devices
don't change.

Cheers,
Mark.

[1] - Adding such a per-device version number to the config file would
solve problem (2)