From: "Luck, Tony" <tony.luck@intel.com>
To: Sohil Mehta <sohil.mehta@intel.com>
Cc: <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>,
Ard Biesheuvel <ardb@kernel.org>,
"H . Peter Anvin" <hpa@zytor.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
"Kirill A . Shutemov" <kas@kernel.org>,
"Rick Edgecombe" <rick.p.edgecombe@intel.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
<linux-kernel@vger.kernel.org>, <linux-efi@vger.kernel.org>
Subject: Re: [PATCH v2 0/3] x86: Extend LASS support to EFI configurations
Date: Thu, 5 Feb 2026 09:47:41 -0800 [thread overview]
Message-ID: <aYTXvX24FuBT49bd@agluck-desk3> (raw)
In-Reply-To: <20260120234730.2215498-1-sohil.mehta@intel.com>
On Tue, Jan 20, 2026 at 03:47:27PM -0800, Sohil Mehta wrote:
> Linear Address Space Separation (LASS) is currently disabled [1] when
> support for vsyscall emulation or EFI is compiled in. This series
> extends LASS support to EFI-enabled configurations.
I tried these patches on a LASS-capable system with a kernel built with
CONFIG_X86_VSYSCALL_EMULATION disabled, and traces added to efi_disable_lass()
and efi_enable_lass().
System boots OK (with a bunch of my trace messages showing that CR4.LASS
was disabled/enabled around EFI calls from several CPUs).
Just for grins I commented out the CR4 changes from the efi_disable_lass()
and efi_enable_lass(). System still boots OK, so it seems the EFI runtime
calls during boot don't have any of the BIOS bugs that require LASS disable.
Tested-by: Tony Luck <tony.luck@intel.com>
-Tony
next prev parent reply other threads:[~2026-02-05 17:47 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-20 23:47 [PATCH v2 0/3] x86: Extend LASS support to EFI configurations Sohil Mehta
2026-01-20 23:47 ` [PATCH v2 1/3] x86/cpu: Defer LASS enabling until userspace comes up Sohil Mehta
2026-02-19 21:02 ` Sohil Mehta
2026-03-03 17:41 ` Dave Hansen
2026-01-20 23:47 ` [PATCH v2 2/3] x86/efi: Disable LASS while executing runtime services Sohil Mehta
2026-01-20 23:47 ` [PATCH v2 3/3] x86/cpu: Remove LASS restriction on EFI Sohil Mehta
2026-02-04 17:08 ` [PATCH v2 0/3] x86: Extend LASS support to EFI configurations Maciej Wieczor-Retman
2026-02-05 17:47 ` Luck, Tony [this message]
2026-02-24 18:45 ` Sohil Mehta
2026-02-24 18:49 ` Ard Biesheuvel
2026-03-03 17:42 ` Dave Hansen
-- strict thread matches above, loose matches on Subject: below --
2026-02-04 17:03 Maciej Wieczor-Retman
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