[Libvir] Fix handling of HVM boot parameters

[Daniel P. Berrange]

On Thu, Aug 10, 2006 at 05:08:58AM -0400, Daniel Veillard wrote:
> On Wed, Aug 09, 2006 at 09:33:11PM -0400, Jeremy Katz wrote:
> > On Thu, 2006-08-10 at 01:00 +0100, Daniel P. Berrange wrote:
> > > I meant to include a complete example XML doc showing the changes in
> > > place, so here is a XML dump from a HVM domain which has been booted
> > > off a CDROM:
> > [snip]
> > >     <disk type='file'>
> > >       <source file='/root/foo.img'/>
> > >       <target dev='ioemu:hda'/>
> > >     </disk>
> > 
> > Given what we know is coming, does it make sense to drop the ioemu: here
> > and just have it be implied for HVM guests?  Accept it if it's there
> > (and then drop it if we're on xend 3.0.3), but not really show it?
> 
>   Sound sensible, the problem is detecting the version of xend, 
> of course you can ask xend, you will get the exact version of the
> compiler used to compile it, but when it comes to xen version itself
>   (xen_major 3) (xen_minor 0) (xen_extra -unstable)
> which makes things a bit hard to distinguish 3.0.2 from 3.0.3 :-\

Basically trying to hook off version number is not ever really going
to be reliable because we need libvirt to be able to work against
development snapshots - features may be introduced during dev that need
detecting before the version number is incremented.

> We could try to use the changest but it's not available in our build
> either.

Hooking off changeset looks & smells like a nasty hack.

What is really needed is a version number for the SEXPR format returned
by XenD. A simple incrementing integer digit would suffice really.

  (xen_sexpr_format 4)

Which could be incremented each time a new capability is introduced,or
an existing one changed. Something to propose upstream asap ?

Regards,
Dan.
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