Re: Configuration vs. compat hints [was Re: [Qemu-devel] [PATCHv3 03/13] qemu: add routines to manage PCI capabilities]

[Mark McLoughlin]

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)