Re: [EXTERNAL] Re: [PATCH 5/9] x86/hyperv: Use vmmcall to implement Hyper-V hypercall in sev-snp enlightened guest

From: Borislav Petkov
Date: Tue Jun 27 2023 - 08:05:38 EST


On Tue, Jun 27, 2023 at 01:50:02PM +0200, Peter Zijlstra wrote:
> On Tue, Jun 27, 2023 at 06:57:28PM +0800, Tianyu Lan wrote:
>
> > > "There is no x86 SEV SNP feature(X86_FEATURE_SEV_SNP) flag
>
> I'm sure we can arrange such a feature if we need it, this isn't rocket
> science. Boris?

https://lore.kernel.org/r/20230612042559.375660-7-michael.roth@xxxxxxx

> This seems to work; it's a bit magical for having a nested ALTERNATIVE
> but the output seems correct (the outer alternative comes last in
> .altinstructions and thus has precedence). Sure the [thunk_target] input
> goes unsed in one of the alteratives, but who cares.

I'd like to avoid the nested alternative if not really necessary. I.e.,
a static_call should work here too no?

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette