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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-doc@vger.kernel.org, "Linux Kernel Mailing List" , linux-efi@vger.kernel.org Message-Id: <202682ea-304d-43b2-8a69-c8bc9d8e3e2c@app.fastmail.com> In-Reply-To: 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> Subject: Re: [PATCH v11 9/9] x86/cpu: Enable LASS by default during CPU initialization Content-Type: text/plain Content-Transfer-Encoding: 7bit On Thu, Oct 30, 2025, at 10:24 AM, Sohil Mehta wrote: > On 10/30/2025 9:53 AM, Andy Lutomirski wrote: > >>> On the other hand, supporting EMULATE mode during a #GP is a bit tricky, >>> which isn't worth the effort. >> >> I would say it's definitely worth the effort, but it probably does make sense to get the rest of the series in a mergeable condition such that it only works with vsyscall=none. > > 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. Ah, I misunderstood you. I agree.