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Mon, 28 Sep 2026 21:00:30 +0000 Date: Mon, 28 Sep 2026 14:00:27 -0700 From: Peter Fang To: "Edgecombe, Rick P" CC: "sathyanarayanan.kuppuswamy@linux.intel.com" , "kas@kernel.org" , "dave.hansen@linux.intel.com" , "seanjc@google.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" , "Bityutskiy, Artem" , "tony.lindgren@linux.intel.com" Subject: Re: [PATCH v5 5/6] x86/tdx: Add a helper to query maximum Quote size Message-ID: References: <20260928100913.2265687-1-peter.fang@intel.com> <20260928100913.2265687-6-peter.fang@intel.com> <8c573cf624eab4c76098f1ccc21afc3e9e40849c.camel@intel.com> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <8c573cf624eab4c76098f1ccc21afc3e9e40849c.camel@intel.com> X-ClientProxiedBy: BY3PR10CA0030.namprd10.prod.outlook.com (2603:10b6:a03:255::35) To CH3PR11MB435924.namprd11.prod.outlook.com (2603:10b6:610:34a::8) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PR11MB435924:EE_|LV3PR11MB8553:EE_ X-MS-Office365-Filtering-Correlation-Id: 3aea1505-4d8c-4902-22d3-08df1da38767 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|23010399003|1800799024|7416014|366016|376014|10067099003|11063799006|22082099003|18002099003|4143699003|56012099006; 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Add a helper to query the size instead of > > exposing tdg_vm_rd() directly, as it can read arbitrary metadata fields. > > > > The reported size covers every Quote type the platform can produce, > > including SGX-based Quotes. > > > > Thanks to Xu Yilun for suggesting this in an off-list discussion. > > Suggesting what? Suggesting using another helper instead of exposing tdg_vm_rd() directly. I'll clarify it in the next version. > > > diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c > > index bcaf4180a8db..323e1efc78ea 100644 > > --- a/arch/x86/coco/tdx/tdx.c > > +++ b/arch/x86/coco/tdx/tdx.c > > @@ -198,6 +198,22 @@ u64 tdx_hcall_get_quote(void *buf, size_t size) > > } > > EXPORT_SYMBOL_GPL(tdx_hcall_get_quote); > > > > +/* > > + * Ask the TDX module what the largest possible Quote might be. > > How about adding the "largest on the host platform" detail to this comment. I'll do that. Thanks. >