Re: [PATCH kernel v3 3/3] x86/sev: Do not handle #VC for DR7 read/write

[Alexey Kardashevskiy]

On 20/1/23 16:12, Nikunj A. Dadhania wrote:
> On 20/01/23 08:40, Alexey Kardashevskiy wrote:
> > With MSR_AMD64_SEV_DEBUG_SWAP enabled, the VM should not get #VC
> > events for DR7 read/write which it rather avoided.
>
> SNP guest feature negotiation patch is part of tip now: https://lore.kernel.org/lkml/167414649850.4906.1693185384677559889.tip-bot2@tip-bot2/

Worth mentioning it is tip/x86/urgent (which does not have 
X86_FEATURE_NO_NESTED_DATA_BP), not tip/master (which has 
X86_FEATURE_NO_NESTED_DATA_BP).

> MSR_AMD64_SNP_DEBUG_SWAP is already defined. As this requires guest side changes, please add MSR_AMD64_SNP_DEBUG_SWAP as part of SNP_FEATURES_PRESENT bit mask.

It is MSR_AMD64_SEV_DEBUG_SWAP (SEV, not SNP), it is an SEV-ES thing. 
Why is that feature negotiation SNP-only and not SEV?


--
Alexey