Re: [PATCH 8/9] x86/cpuid: Introduce missing feature adjustment in calculate_pv_def_policy()

[Jan Beulich <jbeulich@xxxxxxxx>]

On 15.06.2020 16:15, Andrew Cooper wrote:
> This was an accidental asymmetry with the HVM side.
> 
> No change in behaviour at this point.
> 
> Fixes: 83b387382 ("x86/cpuid: Introduce and use default CPUID policies")
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
with a remark:

> --- a/xen/arch/x86/cpuid.c
> +++ b/xen/arch/x86/cpuid.c
> @@ -402,6 +402,8 @@ static void __init calculate_pv_def_policy(void)
>      for ( i = 0; i < ARRAY_SIZE(pv_featureset); ++i )
>          pv_featureset[i] &= pv_def_featuremask[i];
>  
> +    guest_common_feature_adjustments(pv_featureset);
> +
>      sanitise_featureset(pv_featureset);
>      cpuid_featureset_to_policy(pv_featureset, p);
>      recalculate_xstate(p);

These four calls are common to all three callers of the function.
Perhaps them going out of sync would be less likely if all four
called the same helper to carry out these four steps?

Jan