[libvirt] [PATCH 2/3 v4] [UPDATED] PowerPC : Add support for launching VMs in 'compat' mode.

[Daniel P. Berrange]

On Tue, Oct 28, 2014 at 04:43:59PM +0530, Prerna Saxena wrote:
> Apologies, I accidentally posted the older version. Pls ignore the
> previously posted patch 2/3. The updated patch is here :
> 
> >From a98d6787dc4f1d39ae36d78799ecf36018377ec7 Mon Sep 17 00:00:00 2001
> From: Prerna Saxena <prerna at linux.vnet.ibm.com>
> Date: Tue, 28 Oct 2014 15:05:59 +0530
> Subject: [PATCH 2/3] PowerPC : Add support for launching VMs in 'compat' mode.
> 
> PowerISA allows processors to run VMs in binary compatibility ("compat")
> mode supporting an older version of ISA. QEMU has recently added support to
> explicitly denote a VM running in compatibility mode through commit 6d9412ea
> & 8dfa3a5e85.
> Now, a "compat" mode VM can be run by invoking this qemu commandline on a
> POWER8 host:  -cpu host,compat=power7.
> 
> This patch allows libvirt to extend the "fallback" semantics of cpu model to
> describe this new mode for PowerKVM guests.
> As an example:
> When a user wants to request a power7 vm to run in compatibility mode on
> a Power8 host, this can be described in XML as follows :
>   <cpu mode='host-model' match='exact'>
>     <model fallback='compat'>power7</model>

I don't really see any point in adding the fallback='compat' 
attribute. That is  basically always implied if you use
mode=host-model in combination with a named model.

Regards,
Daniel
-- 
|: http://berrange.com      -o-    http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org              -o-             http://virt-manager.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org       -o-       http://live.gnome.org/gtk-vnc :|