Re: [PATCH v2 2/8] x86/mtrr: support setting MTRR state for software defined MTRRs

[Juergen Gross]

On 13.02.23 16:11, Borislav Petkov wrote:
> On Mon, Feb 13, 2023 at 04:03:07PM +0100, Borislav Petkov wrote:
> > > Wouldn't !cpu_feature_enabled(X86_FEATURE_HYPERVISOR) be enough?
> > >
> > > I'm not sure we won't need that for TDX guests, too.
> >
> > See, that's the problem. I wanna have it simple too. Lemme check with
> > dhansen.
>
> He says MTRRs are enabled in TDX guests: "X86_FEATURE_MTRR is fixed to
> 1 in TDX guests."
>
> So we will have to do the more finer-grained check I guess.

Isn't the check for !X86_FEATURE_MTRR && X86_FEATURE_HYPERVISOR enough
then?

Yes, you still could construct cases where it would go wrong, but I don't
think we should over-engineer it.


Juergen

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