From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 62C20C433F5 for ; Fri, 28 Jan 2022 22:58:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241961AbiA1W6n (ORCPT ); Fri, 28 Jan 2022 17:58:43 -0500 Received: from mail.skyhub.de ([5.9.137.197]:53298 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229658AbiA1W6n (ORCPT ); Fri, 28 Jan 2022 17:58:43 -0500 Received: from zn.tnic (dslb-088-067-221-104.088.067.pools.vodafone-ip.de [88.67.221.104]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 782941EC0541; Fri, 28 Jan 2022 23:58:37 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1643410717; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=YiDtT4AmBwaBafxN19hikHkQnXHuV/Zji75Dg4d6z9o=; b=JeMERGTf8a8RMw2DrlfHpHUsES5/Meq6ySSpY6TOuLfyFrvzNtDn7lveOsMTQ4SU6arz+m vxDfM4FJAPWYkgfWaV36naGgiPVOxezlLHTHlm1xJzgUAY1EVilAiIfwlzUYOoK9QYfL72 YM+sGX1caWZrfkO6VxwW0DyxEL2P9J8= Date: Fri, 28 Jan 2022 23:58:32 +0100 From: Borislav Petkov To: Michael Roth Cc: Brijesh Singh , 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 , Ingo Molnar , Joerg Roedel , Tom Lendacky , "H. Peter Anvin" , Ard Biesheuvel , Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Jim Mattson , Andy Lutomirski , Dave Hansen , Sergio Lopez , Peter Gonda , Peter Zijlstra , Srinivas Pandruvada , David Rientjes , Dov Murik , Tobin Feldman-Fitzthum , Vlastimil Babka , "Kirill A . Shutemov" , Andi Kleen , "Dr . David Alan Gilbert" , tony.luck@intel.com, marcorr@google.com, sathyanarayanan.kuppuswamy@linux.intel.com Subject: Re: [PATCH v8 29/40] x86/compressed/64: add support for SEV-SNP CPUID table in #VC handlers Message-ID: References: <20220118142345.65wuub2p3alavhpb@amd.com> <20220118143238.lu22npcktxuvadwk@amd.com> <20220118143730.wenhm2bbityq7wwy@amd.com> <20220118172043.djhy3dwg4fhhfqfs@amd.com> <20220118184930.nnwbgrfr723qabnq@amd.com> <20220119011806.av5rtxfv4et2sfkl@amd.com> <20220119162747.ewgxirwcnrcajazm@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220119162747.ewgxirwcnrcajazm@amd.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, Jan 19, 2022 at 10:27:47AM -0600, Michael Roth wrote: > At that point it's much easier for the guest owner to just check the > CPUID values directly against known good values for a particular > configuration as part of their attestation process and leave the > untrusted cloud vendor out of it completely. So not measuring the > CPUID page as part of SNP attestation allows for that flexibility. Well, in that case, I guess you don't need the sanity-checking in the guest either - you simply add it to the attestation TODO-list for the guest owner to go through: Upon booting, the guest owner should compare the CPUID leafs the guest sees with the ones supplied during boot. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette