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Mon, 18 May 2026 11:29:31 +0000 Date: Mon, 18 May 2026 19:29:11 +0800 From: Chao Gao To: Dave Hansen CC: , , , , , , , , , , , , , , , , , , , , , , Thomas Gleixner , Ingo Molnar , Borislav Petkov , , "H. Peter Anvin" Subject: Re: [PATCH v9 05/23] coco/tdx-host: Expose TDX module version Message-ID: References: <20260513151045.1420990-1-chao.gao@intel.com> <20260513151045.1420990-6-chao.gao@intel.com> <5e097cb0-362a-4dee-af68-9ce583312c97@intel.com> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <5e097cb0-362a-4dee-af68-9ce583312c97@intel.com> X-ClientProxiedBy: KUZPR02CA0014.apcprd02.prod.outlook.com (2603:1096:d10:33::12) To BN7PR11MB2836.namprd11.prod.outlook.com (2603:10b6:406:ad::26) 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: BN7PR11MB2836:EE_|MW4PR11MB6862:EE_ X-MS-Office365-Filtering-Correlation-Id: 0f3a3c23-87da-4b90-da1b-08deb4d0b880 X-LD-Processed: 46c98d88-e344-4ed4-8496-4ed7712e255d,ExtAddr X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|7416014|1800799024|3023799003|4143699003|11063799003|18002099003|22082099003|56012099003; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?K2ZziMeNxvoq5Cjpsnv7rQGolXrh/fScx8RUUgAXPGfQP1nIlajNs8/WyGo8?= =?us-ascii?Q?69EOg7I4+SLTkAYa7GVWgUNRqY+P9nAVLSKfARxeKCe7ZebWza21VyYXKJC8?= =?us-ascii?Q?c4r51+gaa9/EQmY0t2ytGEf1GEWn/bHARGXzEyWbtRTuhSA/iQ42upHC1LNC?= =?us-ascii?Q?54QIfQpCGDAYIvYFT01lMvtgNJXnunY8Z2VQpmO3Gc7eLBY0GWtDzEdYpm6x?= =?us-ascii?Q?swPM1gKVn5hUXdQT2/+Tbb30VqhDXv0Yzz0Xo+DeEwAni8oL+Wt1WlG5JojZ?= =?us-ascii?Q?0Ybb61KO5dAJuLvCJELw/NNIhRbmKh//KcLzmlskjBeWz1Jcw6d0WVOuXfRD?= =?us-ascii?Q?2elD5sUMzZPg9zROaHWF/Qj6Br2ECbeSGeul/HotA4ra400YJ6kmCUe84dPT?= =?us-ascii?Q?Vn8H5NkLA3BYlmS7UjHmENKXh2YooRNA0bqOXTRETiG/HgBzLiJWlsa+eotY?= =?us-ascii?Q?iIjIxPzNbCx5RSAMXNpZegqjT4wVGny48ObLKQvSuQu6hBDTQ6ugL1pNPAY8?= =?us-ascii?Q?qX11YoIUwu/MaDkhRuJCxtlk3lNcjk1lx4+g3RN+EVR10iE7xtW8Wn7FyFLi?= =?us-ascii?Q?YQHIXUr1VIgkaezaoXTTeGMNxfLDGaMinoa5Usupj51vj8Owc5O+/7vVJ1W9?= =?us-ascii?Q?ffe3NUqnNz7QBLrD+2a6exynRVpEo+Xe7umjTPjL0Vex+hmIuxAyXtJgCdV9?= =?us-ascii?Q?4rhI2F7Lgz41DWPb/Cpa6bw4f45wJUde2OJzmMS4QbbQ+36Dj5j6I/ytJ9ba?= =?us-ascii?Q?8DGD8VNT/W1f3n4kUnRCrVZ0PDWR0zE5qBrX5U6++gi+dyP1xV6E6gDkUZS8?= =?us-ascii?Q?7oYb/MGE8VwXwFxSqwGCW/9JetLTnrjYnE5Y0NEipu34jbrZHwyZuLIUkIwU?= =?us-ascii?Q?HXpI2F81GHz5AMKm9a8ElR60ugaIq2w2kBzuuV3zlFql+9xbea2DD7ml9moO?= =?us-ascii?Q?98lqpB5+9pL8q611l9/T0IC42gYsXfGWRWU9RuvEMcH5/V8XN2FCnj9/fLKp?= =?us-ascii?Q?1SoErV0B3WI5SGYf62bB2KS+F/Ho6UcLYZ4LemK2ivv9akow2+pDj8e64dCV?= =?us-ascii?Q?kFNoFPMHzKysqfsY4GJr3qjqTGQgXoV1DUHaM28w3QEnMFkerAIVW8Uh0W4n?= =?us-ascii?Q?fK31NhLpd+NQURRw2fvDV69Oc2VSOkz+mXKF/apyuhFt0cLfKOGgows35tPm?= =?us-ascii?Q?jSW6C2nvjdiyNw0Piv6Y70F7gmUgHaoPUhX9JgQxoYKHA4xaWplML/x4TKLE?= =?us-ascii?Q?UMJRCfRV4EtuOkg99D6Ml2d9AFurtdw9oybeUI1wEHzH3x1hyNci9iStdyn7?= =?us-ascii?Q?gsu/CHdlGOybouaCWMCr3NorDiaJN+DXLRWE/yBI7rhi/Zg+a645nI9+q+Zt?= =?us-ascii?Q?TI2S0DgAaIw9qpxAESBon7alioPJBjKefcRKXuLtXGXPlWJ9f6JmatJ6CjwJ?= =?us-ascii?Q?RrePzOaM+zB3aq3n8RJz2eu8d3o21bzR597UMdVdzDcGWKhozBsDMHBBummG?= =?us-ascii?Q?ON8x4s2j75k342nxaJSJ2dqL5R1LtfTBntFWsKrT81mHDGKiND4M7hmHv/Qi?= =?us-ascii?Q?ud9Mbzn5lN8ReNAvIYj595jOr/gutJ8bO50q2/yYUu2xRDnAo8EWL4LgAscw?= =?us-ascii?Q?9R045qeOBRC/s+0jPlL/SnRT45Jvoxc/BNlDmhZ1q6gg3qfGENRvROnuwNPS?= =?us-ascii?Q?HfPARHkdgGywQxK/1AoD7EFk2YXN0Ag60uIG55pt0zJu4/bOeL5Vl18uugWd?= =?us-ascii?Q?Slwa77ttJA=3D=3D?= X-Exchange-RoutingPolicyChecked: TPnxOMMnskLZ/v7uRG9j+yAnq2Pz8osRjbaA/TVk+XAiEuSqkH0aDfkabj8U3hSgYpcOdnnNGe25wZ7KNgbnhGmVL7FMXaONGyY+lPVIBbdic0N/IcuBgkZj5mZN/vEWPoz3gFamAzkwIvVKneZ/XxbIKTzenSIAElHSADfcfYpTu5aUbu4GV52flzvcSj+cBGiHOYuiIZjtY5SgtXBhBr73diQZar2O7yWadI0Jt/VTQzcseMy/O/q1Mp2Lu4X1O3qSlaCP2AM2VpiYqiavJFJ8G6kG4FZQdKivnp1uY0P/CrZVjQWdb5deocECmwbXuv+vmRi0Kp8E1cWatKHr7w== X-MS-Exchange-CrossTenant-Network-Message-Id: 0f3a3c23-87da-4b90-da1b-08deb4d0b880 X-MS-Exchange-CrossTenant-AuthSource: BN7PR11MB2836.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 May 2026 11:29:30.9490 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 1yBSiUsz5bOAG3ci8un/zqOU3uIbutczjq4J6rnI3byP6CYXIdb16avA4AxIkIFDEV61KK6UCQXaNb7HILTXKQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW4PR11MB6862 X-OriginatorOrg: intel.com On Fri, May 15, 2026 at 09:53:59AM -0700, Dave Hansen wrote: >On 5/13/26 08:09, Chao Gao wrote: >> For TDX module updates, userspace needs to select compatible update >> versions based on the current module version. This design delegates >> module selection complexity to userspace because TDX module update >> policies are complex and version series are platform-specific. > >I'm not sure exactly what a "version series" is. By "version series" I meant release lines such as 1.5.x, 2.0.x, and 3.0.x, but that is not clear from the changelog. >Do you need to say more >than that the policy is complex? I will tighten it up and just say that the update policy is complex. > >> For example, the 1.5.x series is for certain platform generations, while >> the 2.0.x series is intended for others. And TDX module 1.5.x may be >> updated to 1.5.y but not to 1.5.y+1. > >That's not much of an example, IMNHO. How about: > > For example, the 1.5.x series runs on Sapphire Rapids but not > Granite Rapids, which needs 2.0.x. Updates are also constrained > by version distance, so a 1.5.6 module might permit updates to > 1.5.7 but not to 1.5.20. Yes, that is much better than my version. > >> Expose the TDX module version to userspace via sysfs to aid module >> selection. Since the TDX faux device will drive module updates, expose >> the version as its attribute. >> >> One bonus of exposing TDX module version via sysfs is: TDX module >> version information remains available even after dmesg logs are cleared. > >I honestly wouldn't even mention this bit. You don't need a bonus. Sure, I will drop that part. > >> +++ b/Documentation/ABI/testing/sysfs-devices-faux-tdx-host >> @@ -0,0 +1,6 @@ >> +What: /sys/devices/faux/tdx_host/version >> +Contact: linux-coco@lists.linux.dev >> +Description: (RO) Report the version of the loaded TDX module. The TDX module >> + version is formatted as x.y.z, where "x" is the major version, >> + "y" is the minor version and "z" is the update version. Versions >> + are used for bug reporting, TDX module updates etc. > >The "etc." is silly. Just zap it. > >Description: (RO) Report the version of the loaded TDX module. > Formatted as "major.minor.update". Used by TDX module > update tooling. Example: "1.2.03" > >That's at least a wee bit of warning to folks about the leading 0 so if >they are parsing it they are a wee bit careful with it. Thanks, this wording is much better and more concise.