linux-kernel - Re: [PATCH 5/5] x86/CPU/AMD: Track SNP host status with cc_platform

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Date: Thu, 28 Mar 2024 14:41:09 +0100
From: Borislav Petkov <bp@...en8.de>
To: Jeremi Piotrowski <jpiotrowski@...ux.microsoft.com>
Cc: X86 ML <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>,
	KVM <kvm@...r.kernel.org>, Ashish Kalra <ashish.kalra@....com>,
	Joerg Roedel <joro@...tes.org>, Michael Roth <michael.roth@....com>,
	Tom Lendacky <thomas.lendacky@....com>
Subject: Re: [PATCH 5/5] x86/CPU/AMD: Track SNP host status with
 cc_platform_*()

On Thu, Mar 28, 2024 at 12:51:17PM +0100, Jeremi Piotrowski wrote:
> Shouldn't this line be inside the cpu_has(c, X86_FEATURE_SEV_SNP) check?

The cc_vendor is not dependent on X86_FEATURE_SEV_SNP.

> How about turning this into a more specific check:
> 
>   if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP) &&

Why?

The check is "am I running as a hypervisor on baremetal".

-- 
Regards/Gruss,
    Boris.

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