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

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Message-ID: <YiI4GXQt5YOXr4qW@nazgul.tnic>
Date:   Fri, 4 Mar 2022 17:02:33 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Dave Hansen <dave.hansen@...el.com>
Cc:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        tglx@...utronix.de, mingo@...hat.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 Fri, Mar 04, 2022 at 07:47:37AM -0800, Dave Hansen wrote:
> Pure reviewer paranoia. :)
> 
>   https://lore.kernel.org/all/YhN5edJQ+LkVc0us@grain/

This is one of those things where when you look at them months, years
from now, you'd go "WTF was that added for?". Because it clearly is
there to catch, well, something you'll catch anyway in testing. Because
if you fail detecting you're running as a TDX guest, you'll know pretty
early about it.

So if it is pure paranoia, you should drop it. Or if there's at least
some merit for it being there, then slap a comment above it why that
check is happening.

Thx.

-- 
Regards/Gruss,
    Boris.

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