[PATCH] conf: cpu: Add <signature family=X model=X stepping=X/>

[Daniel P. Berrangé]

On Sat, Jun 11, 2022 at 12:46:26PM -0400, Cole Robinson wrote:
> Internally we already collect x86 host family + model + stepping
> numeric values. This exposed them in capabilities CPU output.
> Example:
> 
> $ sudo virsh capabilities | grep -A1 -B1 signature
>       <microcode version='240'/>
>       <signature family='6' model='94' stepping='3'/>
>       <counter name='tsc' frequency='3408010000' scaling='no'/>
> 
> Users need to know these values to calculate an expected.
> SEV-ES/SEV-SNP launch measurement.

More specifically, the VMSA register dumps contain a field that
encodes the family+model+stepping. So given a generic machine
portable VMSA blob, we need to be able to update it with the
family+model+stepping of the specific host executing a VM to
get a machine specific VMSA blob. This is then used in the
launjch measurement validation.


With regards,
Daniel
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