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Thu, 30 Oct 2025 17:24:27 +0000 Message-ID: Date: Thu, 30 Oct 2025 10:24:24 -0700 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v11 9/9] x86/cpu: Enable LASS by default during CPU initialization Content-Language: en-US To: Andy Lutomirski , "H. Peter Anvin" , "the arch/x86 maintainers" , Dave Hansen , Thomas Gleixner , "Ingo Molnar" , Borislav Petkov CC: Jonathan Corbet , Josh Poimboeuf , "Peter Zijlstra (Intel)" , Ard Biesheuvel , "Kirill A . Shutemov" , Xin Li , David Woodhouse , Sean Christopherson , Rick P Edgecombe , "Vegard Nossum" , Andrew Cooper , Randy Dunlap , Geert Uytterhoeven , Kees Cook , Tony Luck , Alexander Shishkin , , "Linux Kernel Mailing List" , References: <20251029210310.1155449-1-sohil.mehta@intel.com> <20251029210310.1155449-10-sohil.mehta@intel.com> <789ADBB5-F7AC-4B08-B343-F23260FB8FBC@zytor.com> <13681100-ddc3-4ef0-bd13-744282324ff1@app.fastmail.com> From: Sohil Mehta In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: SJ0PR05CA0062.namprd05.prod.outlook.com (2603:10b6:a03:332::7) To DS0PR11MB7997.namprd11.prod.outlook.com (2603:10b6:8:125::14) Precedence: bulk X-Mailing-List: linux-efi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS0PR11MB7997:EE_|IA1PR11MB9470:EE_ X-MS-Office365-Filtering-Correlation-Id: 4c4be5dc-33ba-4acb-cd5c-08de17d92d9d 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|376014|7416014|1800799024|366016; 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I meant the full emulation mode where the Vsyscall page is readable. It is only available via vsyscall=emulate. No one should be using that one, right? I thought you and Linus agreed on removing EMULATE mode completely: https://lore.kernel.org/all/CALCETrXHJ7837+cmahg-wjR3iRHbDJ6JtVGaoDFC4dx-L8r8OA@mail.gmail.com/ I agree that it would be worthwhile (and relatively easy) to support the execute (XONLY) mode (that only does instruction fetches). That is what the separate vsyscall series would do once the LASS base is in.