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

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Message-ID: <4de457b3-eec9-5415-7e7f-0d5abd4ca08b@intel.com>
Date:   Fri, 4 Mar 2022 07:47:37 -0800
From:   Dave Hansen <dave.hansen@...el.com>
To:     Borislav Petkov <bp@...en8.de>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc:     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 3/4/22 07:43, Borislav Petkov wrote:
> 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?

Pure reviewer paranoia. :)

  https://lore.kernel.org/all/YhN5edJQ+LkVc0us@grain/