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Tue, 14 Jul 2026 05:54:22 +0000 Date: Mon, 13 Jul 2026 22:54:21 -0700 From: Peter Fang To: Binbin Wu CC: Kiryl Shutsemau , Dave Hansen , Rick Edgecombe , Kuppuswamy Sathyanarayanan , Thomas Gleixner , Ingo Molnar , "Borislav Petkov" , , "H. Peter Anvin" , , , Subject: Re: [PATCH 1/2] x86/tdx: Add helper to query maximum TD Quote size Message-ID: <20260714055421.GB3178326@pedri> References: <20260612110853.3188196-1-peter.fang@intel.com> <20260612110853.3188196-2-peter.fang@intel.com> Content-Type: text/plain; charset="utf-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-ClientProxiedBy: SJ0PR13CA0189.namprd13.prod.outlook.com (2603:10b6:a03:2c3::14) To SJ0PR11MB5645.namprd11.prod.outlook.com (2603:10b6:a03:3b9::19) Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SJ0PR11MB5645:EE_|SJ5PPF77D28E3C2:EE_ X-MS-Office365-Filtering-Correlation-Id: 05b84c5b-2371-4681-0c92-08dee16c5a60 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|7416014|376014|23010399003|366016|22082099003|18002099003|4143699003|56012099006|11063799006; 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The TDX > >> + * guest driver uses it to size the buffer for Quote retrieval. Older TDX > >> + * modules do not support this field and return an error. > >> + * > >> + * Return: Maximum Quote size in bytes on success, or 0 on failure. > >> + */ > >> +u32 tdx_get_max_quote_size(void) > >> +{ > >> + u64 val, ret; > >> + > >> + ret = tdg_vm_rd(TDCS_QUOTE_MAX_SIZE, &val); > >> + > >> + return ret ? 0 : (u32)val; > > > > Cast is redundant. > > I thought in Linux kernel, the explicit cast is often preferred? > E.g. as documentation of the metadata field’s width here? Hm... I asked AI to find some patterns in arch/x86, and looks like the explicit cast is more common... Kiryl are you okay with me keeping the cast? >