Re: [PATCH v5 04/15] x86/mtrr: support setting MTRR state for software defined MTRRs

From: Borislav Petkov
Date: Tue Apr 11 2023 - 13:16:11 EST


On Tue, Apr 11, 2023 at 05:57:07PM +0200, Juergen Gross wrote:
> Short answer: You asked me to add it in V2 of the series.
>
> Longer answer: SEV_SNP guests and TDX guests would cause #VE when writing
> MTRR MSRs.

Ah, sorry. Let's extend the comment then and use your original check:

/*
* Only allowed for special virtualization cases:
* - when running as Hyper-V, SEV-SNP guest using vTOM
* - when running as Xen PV guest
* - when running as SEV-SNP or TSX guest to avoid unnecessary
* VMM communication/Virtualization exceptions (#VC, #VE)
*/
if (!hv_is_isolation_supported() &&
!cpu_feature_enabled(X86_FEATURE_XENPV) &&
!cc_platform_has(CC_ATTR_GUEST_SEV_SNP) &&
!cpu_feature_enabled(X86_FEATURE_TDX_GUEST))
return;

Thx.

--
Regards/Gruss,
Boris.

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