Re: [PATCH v8 20/40] x86/sev: Use SEV-SNP AP creation to start secondary CPUs

Borislav Petkov
2022-01-13T12:22:06Z

On Wed, Jan 12, 2022 at 10:33:40AM -0600, Brijesh Singh wrote:
> Yes, the SEV-SNP feature is required. Anyway, I will improve a check. We
> will reach to AP creation only after SEV-SNP feature is checked, so, in AP
> creation routine we just need to check for the AP_CREATION specific feature
> flag; I will add comment about it.

Right, at least a comment explaining why the bits are ORed.
>
> > You can still enforce that requirement in the test though.
> >
> > Or all those SEV features should not be bits but masks -
> > GHCB_HV_FT_SNP_AP_CREATION_MASK for example, seeing how the others
> > require the previous bits to be set too.

Thinking about this more, calling it a "mask" might not be optimal here
as you use masks usually to, well, mask out bits, etc. So I guess a
comment explaning why the OR-in of bit 0...

--
Regards/Gruss,
Boris.