Re: [PATCH] x86/cpu-policy: Extend the guest max policy max leaf/subleaves

["Alejandro Vallejo" <alejandro.vallejo@xxxxxxxxx>]

On Tue Oct 29, 2024 at 5:55 PM GMT, Andrew Cooper wrote:
> We already have one migration case opencoded (feat.max_subleaf).  A more
> recent discovery is that we advertise x2APIC to guests without ensuring that
> we provide max_leaf >= 0xb.
>
> In general, any leaf known to Xen can be safely configured by the toolstack if
> it doesn't violate other constraints.
>
> Therefore, introduce guest_common_{max,default}_leaves() to generalise the
> special case we currently have for feat.max_subleaf, in preparation to be able
> to provide x2APIC topology in leaf 0xb even on older hardware.
>
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Reviewed-by: Alejandro Vallejo <alejandro.vallejo@xxxxxxxxx>

Cheers,
Alejandro