linux-kernel - Re: [PATCH 07/26] x86/tdx: Handle CPUID via #VE

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Message-ID: <Yc87mpjSNbgUtqKV@zn.tnic>
Date:   Fri, 31 Dec 2021 18:19:35 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc:     tglx@...utronix.de, mingo@...hat.com, dave.hansen@...el.com,
        luto@...nel.org, peterz@...radead.org,
        sathyanarayanan.kuppuswamy@...ux.intel.com, aarcange@...hat.com,
        ak@...ux.intel.com, dan.j.williams@...el.com, david@...hat.com,
        hpa@...or.com, jgross@...e.com, jmattson@...gle.com,
        joro@...tes.org, jpoimboe@...hat.com, knsathya@...nel.org,
        pbonzini@...hat.com, sdeep@...are.com, seanjc@...gle.com,
        tony.luck@...el.com, vkuznets@...hat.com, wanpengli@...cent.com,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 07/26] x86/tdx: Handle CPUID via #VE

On Tue, Dec 14, 2021 at 06:02:45PM +0300, Kirill A. Shutemov wrote:
> In TDX guests, most CPUID leaf/sub-leaf combinations are virtualized
> by the TDX module while some trigger #VE.
> 
> Implement the #VE handling for EXIT_REASON_CPUID by handing it through
> the hypercall, which in turn lets the TDX module handle it by invoking
> the host VMM.
> 
> More details on CPUID Virtualization can be found in the TDX module
> specification [1], the section titled "CPUID Virtualization".

The exact name and section should be enough to find the spec document
because...

> 
> [1] - https://software.intel.com/content/dam/develop/external/us/en/documents/tdx-module-1.0-public-spec-v0.931.pdf

... those links are never stable and become stale eventually. Just save
yourself the effort of adding them to commit messages.

-- 
Regards/Gruss,
    Boris.

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