From: David Laight <david.laight.linux@gmail.com>
To: 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: Thu, 30 Oct 2025 21:13:18 +0000 [thread overview]
Message-ID: <20251030211318.74d90c3f@pumpkin> (raw)
In-Reply-To: <d1b5698e-94ab-45a2-a472-4488895d55bb@intel.com>
On Thu, 30 Oct 2025 09:44:02 -0700
Sohil Mehta <sohil.mehta@intel.com> wrote:
> On 10/30/2025 8:45 AM, Andy Lutomirski wrote:
> > On Thu, Oct 30, 2025, at 1:40 AM, H. Peter Anvin wrote:
> >> Legacy vsyscalls have been obsolete for how long now?
> >
> > A looooong time.
> >
> > I would suggest defaulting LASS to on and *maybe* decoding just enough to log, once per boot, that a legacy vsyscall may have been attempted. It’s too bad that #GP doesn’t report the faulting address.
> >
>
> 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.
David
next prev parent reply other threads:[~2025-10-30 21:13 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 [this message]
2025-10-31 6:41 ` H. Peter Anvin
2025-10-31 16:55 ` Dave Hansen
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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