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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?1BVNU6fhNrYAqIeTNYhnaVbNho0CkKnCE+DeHoYVUJ4e+rN3WU/UTCKQoWlk?= =?us-ascii?Q?vRlTp6wZP9aT9zbeAHY+Qr7bMpWEaB78U5SddU+UZeUfZMI/wr/6USMeEtTa?= =?us-ascii?Q?X8wi5p/dfU/sCDXEpcSCyQ76Jt9/QJnoS2QUHIIlYHytzYQkz6fAdQcfDUp+?= =?us-ascii?Q?XYc5dm0uiam5QsdkMN5RmCIKoZrzvqxeVd+joDXZeTuRQU7bd941eEDsStuH?= =?us-ascii?Q?42TmgMzWwfj2e1dbkga9oaEoyeemohhFDnSjaIDTwNXlboK6OHCm3nKXKhzK?= =?us-ascii?Q?8y403CLxThUs2NLg1d5raxHAhN3eUnb05FquXQ2r7QkzuaFvowtfPjN5itDP?= =?us-ascii?Q?oILLzNKnBgrqLzMubtKNwEnq51wA/67vHQ2S75Yyj+6ULen7B1o5yyu9qBa4?= =?us-ascii?Q?GmQ+dPrOKp7b8KiGXLxKV3RxHyEWiYe+kYXVf/fZkUxNbXglK8ZaUQwpvGhP?= =?us-ascii?Q?9qANMcBRXD71fw5B4Qiyvwwvvui+7rq4OvmND/iqJ5V8Ir5/w5DcB+Op9mYq?= =?us-ascii?Q?82RV472ID/GwlwU5PBppOq5GOD7eNmXH8a/ClBIX2jlL9RR2SpNd9BPqf/2w?= =?us-ascii?Q?+s0nVutzQlaZmg4C8tZIBV4mW2Mj1Voe3AgjcE2woHdR02Zq9SuoSVOSPPoo?= =?us-ascii?Q?1GnJTToakaKdMFdXrMK2uHwJ+Of6Jezzx/uOyqiHta5W1d3RBUH7xArSmAAP?= =?us-ascii?Q?IRrWTpYD2+Nqya0T2uPsD14BlDt/j2bd6BN+GV+j99MX8j0ZZu22qI9EIBc+?= =?us-ascii?Q?8tQvDVMAAITZHI+JGD7SqlRfqW5/hFpW/FERnwklVr+fj4GRha2C/PFndBgK?= =?us-ascii?Q?f4YB6vkEMODmnECecs21QOmUgrQZsSHoTOn3IO3kB08ss+ES6gvtYyJ+/E87?= =?us-ascii?Q?FBM+buEj67TcnI7Mwfn5z3cB02L07zGid/0HiHxEVS6VRlWH03R6z/GXH1Is?= =?us-ascii?Q?KWMZFp/Flkkem4CeMzmFb7YSvqNXxmex2nrCf5d4lP4YksJ0vbNkJuysbC9m?= =?us-ascii?Q?Vkt9dpUK9NidQnc7T9v/40jUvzuJi7PLsqGCCpNCBfBIiy4A0BV/sOFd41Cw?= =?us-ascii?Q?tUM+YxTu1rSTXPQvhbjqwY8Q9BKHff7e7nf5hIlbr+GE2p/35P5mRhBQigyC?= =?us-ascii?Q?u64q6qpSGiRATZA1ABDtap8MjSojQJNbHpexhae3KrQ0iJ4XHqgxRRBya9Xj?= =?us-ascii?Q?IVspFmK8r08olaHSntbyT2ukE6r5awmJhqbWqNbM7Lmsw69puIhkwfOxAKbW?= =?us-ascii?Q?p1o8GkUppSDdLIl0A7UKVdMDO6VAgWBX94t7vF5P9D6tsAPP+E+e8GSiVX50?= =?us-ascii?Q?WLB8mlrEWAey9L9IEMooez//4osZqs9IKMzm6MrG/LRpcX7Rohm1Ui3F8Brr?= =?us-ascii?Q?o/pb/3/EcZZMsRe1bNaMZIpTUyj9m7Mccxfr2D4sVmMCs0Vzt3VyBuFwYYgY?= =?us-ascii?Q?erA22QXqDZqNQYK5jt4dj8d1DM4yJZomgBdH8tqy1FHczPj7GaHMe1RI56tC?= =?us-ascii?Q?1Dt4h5+SULL/1os4ty3I9vwTdSxCP39vbnW0UWzPg3SBA0AngvHjeKIUOkEw?= =?us-ascii?Q?m5f7kuJOMuAftDHZcEcid/uXi8+2l1WcWnwHDt7jnH2IrKojOi7PSY6gUPJJ?= =?us-ascii?Q?xw=3D=3D?= X-MS-Exchange-CrossTenant-Network-Message-Id: 3700f782-b477-4398-bed2-08da84f886e6 X-MS-Exchange-CrossTenant-AuthSource: SJ1PR11MB6201.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 23 Aug 2022 11:13:37.7621 (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: ny/Sxl/zXTvKVsfc3U3F4n/SR8fsb8LKl8V28Sg2Yh/JnQqSDREuQfIJbGnqo263FrLKyEF1tlCNDIfJKDjRUg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN6PR1101MB2147 X-OriginatorOrg: intel.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 19, 2022 at 12:24:41PM +0200, Borislav Petkov wrote: > On Wed, Aug 17, 2022 at 05:11:23AM +0000, Ashok Raj wrote: > > When save_microcode_patch() is looking to replace an existing microcode in > > the cache, current code is *only* checks the CPU sig/pf in the main > > Write those "sig/pf" things out once so that it is clear what that is. Thanks, will do. > > > header. Microcode can carry additional sig/pf combinations in the extended > > signature table, which is completely missed today. > > > > For e.g. Current patch is a multi-stepping patch and new incoming patch is > > a specific patch just for this CPUs stepping. > > > > patch1: > > fms3 <--- header FMS > > ... > > ext_sig: > > fms1 > > fms2 > > > > patch2: new > > fms2 <--- header FMS > > > > Current code takes only fms3 and checks with patch2 fms2. > > So, find_matching_signature() does all the signatures matching and > scanning already. If anything, that function should tell its callers > whether the patch it is looking at - the fms2 one - should replace the > current one or not. > > I.e., all the logic to say how strong a patch match is, should be > concentrated there. And then the caller will do the according action. I updated the commit log accordingly. Basically find_matching_signature() is only intended to find a CPU's sig/pf against a microcode image and not intended to compare between two different images. > > > saved_patch.header.fms3 != new_patch.header.fms2, so save_microcode_patch > > saves it to the end of list instead of replacing patch1 with patch2. > > > > There is no functional user observable issue since find_patch() skips > > patch versions that are <= current_patch and will land on patch2 properly. > > > > Nevertheless this will just end up storing every patch that isn't required. > > Kernel just needs to store the latest patch. Otherwise its a memory leak > > that sits in kernel and never used. > > Oh well. > > > Cc: stable@vger.kernel.org > > Why? We have some code to support model specific microcode rollback support. This code is just internal. That codebase triggered the bug. I'll drop the Cc next time. Cheers, Ashok