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Thu, 27 Aug 2026 22:22:49 +0000 Date: Thu, 27 Aug 2026 15:22:46 -0700 From: Peter Fang To: "Edgecombe, Rick P" CC: "sathyanarayanan.kuppuswamy@linux.intel.com" , "kas@kernel.org" , "dave.hansen@linux.intel.com" , "bp@alien8.de" , "x86@kernel.org" , "binbin.wu@linux.intel.com" , "hpa@zytor.com" , "mingo@redhat.com" , "linux-kernel@vger.kernel.org" , "Li, Xiaoyao" , "tglx@kernel.org" , "kvm@vger.kernel.org" , "linux-coco@lists.linux.dev" Subject: Re: [PATCH v3 0/4] tdx-guest: Make Quote buffer size dynamic Message-ID: <20260827222246.GE33657@pedri> References: <20260729122939.1340412-1-peter.fang@intel.com> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: SJ0PR13CA0024.namprd13.prod.outlook.com (2603:10b6:a03:2c0::29) To CH3PR11MB435924.namprd11.prod.outlook.com (2603:10b6:610:34a::8) Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PR11MB435924:EE_|PH0PR11MB4885:EE_ X-MS-Office365-Filtering-Correlation-Id: 9fbf7191-000e-4b40-a263-08df0489ba16 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|376014|1800799024|23010399003|366016|56012099006|10067099003|22082099003|11063799006|4143699003|18002099003; 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As > > cryptographic algorithms evolve, TD Quote sizes also grow. A previous > > commit [2] increased the guest driver's fixed-size Quote buffer to 128 > > KB to accommodate DICE Quotes, but it may still be insufficient when > > those Quotes use post-quantum cryptography (PQC). PQC certificate chains > > are roughly 10x-15x larger than conventional ones, which can increase > > Quote sizes significantly. > > For the DICE host changes, the reason given for why the host side quote > operation is TD scoped was to avoid changing the guest by increasing the report > size. But actually, as this coverletter points out, the guest buffer sizes do > get changed. So I think we should pause this series until we sort out the This thread has led to a lot of great discussion, and I think perhaps we can resume reviewing this series? The main open topics now seem to be the guest report and potential alternatives to GetQuote, but none of them change the fact that the quote size is growing as crypto stuff evolves... So this series applies to all the options on the table right now. > inconsistencies in the reasoning. Depending, we may want to circle back with KVM > folks on what the options actually are for the DICE quote operation.