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Wed, 18 Mar 2026 16:49:27 +0000 Message-ID: <1ecd023d-2bd4-4a94-b315-65b9d140030f@intel.com> Date: Wed, 18 Mar 2026 09:49:25 -0700 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/3] x86/cpu: Enable FSGSBASE early in cpu_init_exception_handling() Content-Language: en-US To: Dave Hansen , Borislav Petkov CC: Nikunj A Dadhania , , , , , , , , , , , , , References: <20260318075654.1792916-1-nikunj@amd.com> <20260318075654.1792916-2-nikunj@amd.com> <20260318153918.GBabrHJjRA6T2crJbK@fat_crate.local> <09fd1a56-71bc-4fd0-8d07-724ca1c830f6@intel.com> From: Sohil Mehta In-Reply-To: <09fd1a56-71bc-4fd0-8d07-724ca1c830f6@intel.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: SJ0PR03CA0344.namprd03.prod.outlook.com (2603:10b6:a03:39c::19) To DS0PR11MB7997.namprd11.prod.outlook.com (2603:10b6:8:125::14) 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: DS0PR11MB7997:EE_|SJ2PR11MB8452:EE_ X-MS-Office365-Filtering-Correlation-Id: 04d7f6fb-5ced-4028-f4c1-08de850e514d X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|366016|1800799024|22082099003|18002099003|56012099003; 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I'm OK leaving it like > Nikunj's original version. Sorry about the churn. While reviewing the patch, I was trying to understand the difference between the early exception handlers and the one setup by cpu_init_exception_handling() on BSP and APs. It caught my attention that the code comment said, "Enable the feature (FSGSBASE) before any exceptions occur." I got a bit carried away with the technicalities!