Re: [Qemu-devel] [Xen-devel] [PATCH] Remove hardcoded xen-platform device initialization

[Paolo Bonzini]

Il 19/06/2013 10:56, Ian Campbell ha scritto:
> The case with xl is more like your example 5:

Ok, that's what I remembered. :)

> > Example 5: you use "virsh create" to start a VM based on an XML file,
> > rather than "virsh define"+"virsh start" as in examples 1-2.  You lose
> > any guarantee that hardware does not change.  Not frowned upon as much
> > as example 4, since the VM is supposed to be transient.
> 
> For something like xapi we'd likely want to support some sort of model
> similar to libvirt, so whatever we do at the libxl layer needs to
> consider both approaches.

I think xapi can itself query qemu if this is the case (in this respect,
libvirt is somewhat in the middle between xl and xapi, depending on
whether you use transient or persistent domains).  Or perhaps you can
add an xl command to query qemu and provide capabilities.

xl can default to some "blessed" old-enough machine if it is available
or just the newest "pc" if the blessed machine is unavailable.  And of
course it can be overridden by the guest config.

Paolo