From: Dave Hansen <dave.hansen@intel.com>
To: David Laight <david.laight.linux@gmail.com>,
Sohil Mehta <sohil.mehta@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
the arch/x86 maintainers <x86@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Jonathan Corbet <corbet@lwn.net>,
Josh Poimboeuf <jpoimboe@kernel.org>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Ard Biesheuvel <ardb@kernel.org>,
"Kirill A . Shutemov" <kas@kernel.org>, Xin Li <xin@zytor.com>,
David Woodhouse <dwmw@amazon.co.uk>,
Sean Christopherson <seanjc@google.com>,
Rick P Edgecombe <rick.p.edgecombe@intel.com>,
Vegard Nossum <vegard.nossum@oracle.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Randy Dunlap <rdunlap@infradead.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Kees Cook <kees@kernel.org>, Tony Luck <tony.luck@intel.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
linux-doc@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-efi@vger.kernel.org
Subject: Re: [PATCH v11 9/9] x86/cpu: Enable LASS by default during CPU initialization
Date: Fri, 31 Oct 2025 09:55:01 -0700 [thread overview]
Message-ID: <f559e1fa-dfc6-435f-9337-30315891a394@intel.com> (raw)
In-Reply-To: <20251030211318.74d90c3f@pumpkin>
On 10/30/25 14:13, David Laight wrote:
>> Unfortunately, CONFIG_X86_VSYSCALL_EMULATION defaults to y. Also, the
>> default Vsyscall mode is XONLY. So even if vsyscalls are deprecated,
>> there is a non-zero possibility someone would complain about it.
> Presumably a command line parameter could be used to disable LASS
> in order to enable vsyscall emulation?
>
> That might let LASS be enabled by default.
Sure... There are a million ways to skin this cat. That's the problem.
The compile switch is the smallest amount of code with the fewest
implications to ABI or documentation that we can muster. All I'm saying
is we should _start_ here, not _end_ here.
If anyone agrees with that approach, acks would be appreciated.
next prev parent reply other threads:[~2025-10-31 16:55 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-29 21:03 [PATCH v11 0/9] x86: Enable Linear Address Space Separation support Sohil Mehta
2025-10-29 21:03 ` [PATCH v11 1/9] x86/cpufeatures: Enumerate the LASS feature bits Sohil Mehta
2025-10-31 17:03 ` Dave Hansen
2025-10-29 21:03 ` [PATCH v11 2/9] x86/cpu: Add an LASS dependency on SMAP Sohil Mehta
2025-10-31 17:04 ` Dave Hansen
2025-10-29 21:03 ` [PATCH v11 3/9] x86/asm: Introduce inline memcpy and memset Sohil Mehta
2025-10-31 17:06 ` Dave Hansen
2025-10-29 21:03 ` [PATCH v11 4/9] x86/alternatives: Disable LASS when patching kernel code Sohil Mehta
2025-10-31 17:10 ` Dave Hansen
2025-11-10 18:15 ` Sohil Mehta
2025-11-10 19:09 ` H. Peter Anvin
2025-11-10 19:24 ` Borislav Petkov
2025-11-12 13:56 ` Ard Biesheuvel
2025-11-12 14:51 ` Dave Hansen
2025-11-12 14:57 ` H. Peter Anvin
2025-11-12 15:18 ` Ard Biesheuvel
2025-11-12 15:23 ` H. Peter Anvin
2025-11-12 15:28 ` Ard Biesheuvel
2025-11-12 15:47 ` H. Peter Anvin
2025-11-12 16:18 ` Sohil Mehta
2025-11-12 16:26 ` H. Peter Anvin
2025-11-12 16:29 ` H. Peter Anvin
2025-10-29 21:03 ` [PATCH v11 5/9] x86/efi: Disable LASS while mapping the EFI runtime services Sohil Mehta
2025-10-31 17:11 ` Dave Hansen
2025-10-31 17:38 ` Andy Lutomirski
2025-10-31 17:41 ` Dave Hansen
2025-10-31 18:03 ` Sohil Mehta
2025-10-31 18:12 ` Dave Hansen
2025-11-07 9:04 ` Peter Zijlstra
2025-11-07 9:22 ` Ard Biesheuvel
2025-11-07 9:27 ` H. Peter Anvin
2025-11-07 9:35 ` Ard Biesheuvel
2025-11-07 9:40 ` Peter Zijlstra
2025-11-07 10:09 ` Ard Biesheuvel
2025-11-07 10:27 ` Peter Zijlstra
2025-11-08 0:48 ` Andy Lutomirski
2025-11-08 16:18 ` H. Peter Anvin
2025-11-08 22:50 ` H. Peter Anvin
2025-11-07 10:10 ` Peter Zijlstra
2025-11-07 10:17 ` Ard Biesheuvel
2025-10-31 19:04 ` Sohil Mehta
2025-11-07 7:36 ` Sohil Mehta
2025-10-31 18:32 ` Sohil Mehta
2025-10-29 21:03 ` [PATCH v11 6/9] x86/kexec: Disable LASS during relocate kernel Sohil Mehta
2025-10-31 17:14 ` Dave Hansen
2025-10-29 21:03 ` [PATCH v11 7/9] x86/traps: Communicate a LASS violation in #GP message Sohil Mehta
2025-10-31 17:16 ` Dave Hansen
2025-10-31 19:59 ` Sohil Mehta
2025-10-31 20:03 ` Andy Lutomirski
2025-10-31 20:56 ` Dave Hansen
2025-10-29 21:03 ` [PATCH v11 8/9] selftests/x86: Update the negative vsyscall tests to expect a #GP Sohil Mehta
2025-10-31 17:20 ` Dave Hansen
2025-10-29 21:03 ` [PATCH v11 9/9] x86/cpu: Enable LASS by default during CPU initialization Sohil Mehta
2025-10-30 8:40 ` H. Peter Anvin
2025-10-30 15:45 ` Andy Lutomirski
2025-10-30 16:44 ` Sohil Mehta
2025-10-30 16:53 ` Andy Lutomirski
2025-10-30 17:24 ` Sohil Mehta
2025-10-30 17:31 ` Andy Lutomirski
2025-10-30 21:13 ` David Laight
2025-10-31 6:41 ` H. Peter Anvin
2025-10-31 16:55 ` Dave Hansen [this message]
2025-10-30 16:27 ` Dave Hansen
2025-11-07 8:01 ` H. Peter Anvin
2025-11-07 20:08 ` Sohil Mehta
2025-10-31 17:21 ` Dave Hansen
2025-10-31 20:04 ` Sohil Mehta
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