[libvirt] CLZERO support for AMD

[Daniel P. Berrangé]

On Wed, Nov 27, 2019 at 11:10:21AM +0000, Ani Sinha wrote:
> Hi :
> 
> I see a commit in qemu that adds support for CLZERO but in CPUIDs. :
> 
> commit e900135dcfb676a4019dc206395e02db5d1de0d6
> Author: Sebastian Andrzej Siewior <bigeasy at linutronix.de>
> Date: Wed Sep 25 23:49:48 2019 +0200
> 
> i386: Add CPUID bit for CLZERO and XSAVEERPTR
> 
> The CPUID bits CLZERO and XSAVEERPTR are availble on AMD's ZEN platform
> and could be passed to the guest.
> 
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy at linutronix.de>
> Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
> 
> Is there a corresponding change in libvirt adding this capability? Libvirt complains when I add it manually in the vm xml:
> 
> # virsh create newvm.xml 
> error: Failed to create domain from newvm.xml
> error: unsupported configuration: unknown CPU feature: clzero
> 
> # grep clzero newvm.xml 
>     <feature policy='require' name='clzero'/>
> 
> Should we add it?

Yes, if it is supported by QEMU to expose to a guest, then it should be
added to libvirt too.

Presumably only needs add an addition to src/cpu_maps/x86_features.xml

Regards,
Daniel
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