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Date: Fri, 7 Jan 2022 12:54:25 +0100
From: Borislav Petkov <bp@alien8.de>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>, x86@kernel.org,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org,
	linux-coco@lists.linux.dev, linux-mm@kvack.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Joerg Roedel <jroedel@suse.de>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	"H. Peter Anvin" <hpa@zytor.com>, Ard Biesheuvel <ardb@kernel.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Jim Mattson <jmattson@google.com>,
	Andy Lutomirski <luto@kernel.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Sergio Lopez <slp@redhat.com>, Peter Gonda <pgonda@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
	David Rientjes <rientjes@google.com>,
	Dov Murik <dovmurik@linux.ibm.com>,
	Tobin Feldman-Fitzthum <tobin@ibm.com>,
	Michael Roth <michael.roth@amd.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	"Kirill A . Shutemov" <kirill@shutemov.name>,
	Andi Kleen <ak@linux.intel.com>,
	"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
	tony.luck@intel.com, marcorr@google.com,
	sathyanarayanan.kuppuswamy@linux.intel.com
Subject: Re: [PATCH v8 27/40] x86/boot: Add Confidential Computing type to
 setup_data
Message-ID: <Ydgp8bjPdFTpD9KC@zn.tnic>
References: <20211210154332.11526-1-brijesh.singh@amd.com>
 <20211210154332.11526-28-brijesh.singh@amd.com>
 <1fdaca61-884a-ac13-fb33-a47db198f050@intel.com>
 <ba485a09-9c35-4115-decc-1b9c25519358@amd.com>
 <2a5cfbd0-865c-2a8b-b70b-f8f64aba5575@intel.com>
 <f442ca7f-4530-1443-27eb-206d6ca0e7a4@amd.com>
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In-Reply-To: <48625a39-9e31-d7f2-dccf-74e9c27126f5@intel.com>

On Mon, Dec 13, 2021 at 07:08:07AM -0800, Dave Hansen wrote:
> Could you please make the structure's size invariant?  That's great if
> there's no problem in today's implementation, but it's best no to leave
> little land mines like this around.  Let's say someone copies your code
> as an example of something that interacts with a firmware table a few
> years or months down the road.

Btw, about that cc blob thing: is TDX going to need something like that
too and if so, can they use it too?

-- 
Regards/Gruss,
    Boris.

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