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Date:   Mon, 21 Feb 2022 16:53:34 +0300
From:   "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To:     Cyrill Gorcunov <gorcunov@gmail.com>
Cc:     tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
        dave.hansen@intel.com, luto@kernel.org, peterz@infradead.org,
        sathyanarayanan.kuppuswamy@linux.intel.com, aarcange@redhat.com,
        ak@linux.intel.com, dan.j.williams@intel.com, david@redhat.com,
        hpa@zytor.com, jgross@suse.com, jmattson@google.com,
        joro@8bytes.org, jpoimboe@redhat.com, knsathya@kernel.org,
        pbonzini@redhat.com, sdeep@vmware.com, seanjc@google.com,
        tony.luck@intel.com, vkuznets@redhat.com, wanpengli@tencent.com,
        x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCHv3 13/32] x86/tdx: Detect TDX at early kernel
 decompression time
Message-ID: <20220221135334.zzcozxu6vyskxjzo@black.fi.intel.com>
References: <20220218161718.67148-1-kirill.shutemov@linux.intel.com>
 <20220218161718.67148-14-kirill.shutemov@linux.intel.com>
 <YhN5edJQ+LkVc0us@grain>
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On Mon, Feb 21, 2022 at 02:37:29PM +0300, Cyrill Gorcunov wrote:
> On Fri, Feb 18, 2022 at 07:16:59PM +0300, Kirill A. Shutemov wrote:
> ...
> > 
> > +
> > +void early_tdx_detect(void)
> > +{
> > +	u32 eax, sig[3];
> > +
> > +	cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, &sig[0], &sig[2],  &sig[1]);
> > +
> > +	if (memcmp(TDX_IDENT, sig, 12))
> > +		return;
> 
> Maybe worth to guard ourself, like
> 
> 	BUILD_BUG_ON(sizeof(sig) != (sizeof(TDX_IDENT)-1));
> 	if (memcmp(TDX_IDENT, sig, sizeof(sig))
> 		return;

Sure. Will do.

-- 
 Kirill A. Shutemov