On 1/7/25 06:37, Borislav Petkov wrote: > On Tue, Jan 07, 2025 at 05:13:03PM +0530, Nikunj A. Dadhania wrote: >>>> + case CC_ATTR_GUEST_SNP_SECURE_TSC: >>>> + return (sev_status & MSR_AMD64_SEV_SNP_ENABLED) && >>> >>> This is new here? >> >> Yes, this was suggested by Tom here [1] > > Either of you care to explain why this is needed? > >>>> + (sev_status & MSR_AMD64_SNP_SECURE_TSC); > > I would strongly assume that whatever sets MSR_AMD64_SNP_SECURE_TSC will have > checked/set MSR_AMD64_SEV_SNP_ENABLED already. Yes, but from a readability point of view this makes it perfectly clear that Secure TSC is only for SNP guests. It's not on a fast path, so I don't think it hurts anything by having the extra check. But if you prefer the previous check, I'm ok with that. Thanks, Tom >
