[libvirt] [PATCH 3/3] qemu: Adapt to changed ppc64 CPU model names

[Andrea Bolognani]

On Thu, 2018-05-17 at 17:33 +0200, Jiri Denemark wrote:
[...]
> --- a/tests/domaincapsschemadata/qemu_2.12.0.ppc64.xml
> +++ b/tests/domaincapsschemadata/qemu_2.12.0.ppc64.xml
> @@ -25,7 +25,11 @@
>      <mode name='host-model' supported='yes'>
>        <model fallback='allow'>POWER8</model>
>      </mode>

This is quite suspicious - it looks like a proper CPU model, but
it's really a compatibility mode, so it should be lowercase rather
than uppercase. You certainly won't be able to use

  <cpu mode='host-model>
    <model>POWER8</model>
  </cpu>

so why are we advertising the uppercase variant here? Am I missing
something?

> -    <mode name='custom' supported='no'/>
> +    <mode name='custom' supported='yes'>
> +      <model usable='unknown'>POWER9</model>
> +      <model usable='unknown'>POWER8</model>
> +      <model usable='unknown'>POWER7</model>
> +    </mode>

This is of course an improvement, but I'm not sure we want to keep
exposing uppercase model names to users.

I understand we need to keep accepting them for compatibility
reasons, but since QEMU has moved to lowercase CPU model names
wouldn't it make sense for libvirt to follow suit?

Doing so would have the interesting side effect of making the whole
mess with compat modes somewhat sane, at least when it comes to not
having two entirely separate set of names differing only in case.

Then again, I might just be missing some very obvious issues
preventing us from using lowercase names :)

-- 
Andrea Bolognani / Red Hat / Virtualization