linux-kernel - Re: [PATCHv5 01/30] x86/tdx: Detect running as a TDX guest in early boot

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Message-ID: <YiIzgg3Ql81He0X9@nazgul.tnic>
Date:   Fri, 4 Mar 2022 16:43:11 +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,
        thomas.lendacky@....com, brijesh.singh@....com, x86@...nel.org,
        linux-kernel@...r.kernel.org,
        Dave Hansen <dave.hansen@...ux.intel.com>
Subject: Re: [PATCHv5 01/30] x86/tdx: Detect running as a TDX guest in early
 boot

On Wed, Mar 02, 2022 at 05:27:37PM +0300, Kirill A. Shutemov wrote:
> +void __init tdx_early_init(void)
> +{
> +	u32 eax, sig[3];
> +
> +	cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, &sig[0], &sig[2],  &sig[1]);
> +
> +	BUILD_BUG_ON(sizeof(sig) != sizeof(TDX_IDENT) - 1);

That's new.

Is that pure paranoia or what are you protecting here against?

-- 
Regards/Gruss,
    Boris.

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