From: Sohil Mehta <sohil.mehta@intel.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
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Cc: Jonathan Corbet <corbet@lwn.net>, Ingo Molnar <mingo@kernel.org>,
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<linux-efi@vger.kernel.org>, <linux-mm@kvack.org>
Subject: Re: [PATCHv9 16/16] x86: Re-enable Linear Address Masking
Date: Tue, 8 Jul 2025 22:31:05 -0700 [thread overview]
Message-ID: <b1408df7-abb4-4ac5-aff7-c04fda7dec7c@intel.com> (raw)
In-Reply-To: <20250707080317.3791624-17-kirill.shutemov@linux.intel.com>
On 7/7/2025 1:03 AM, Kirill A. Shutemov wrote:
> This reverts commit 3267cb6d3a174ff83d6287dcd5b0047bbd912452.
>
> LASS mitigates the Spectre based on LAM (SLAM) [1] and the previous
> commit made LAM depend on LASS, so we no longer need to disable LAM at
> compile time, so revert the commit that disables LAM.
>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
You may have missed my comments in the previous revision.
https://lore.kernel.org/all/af709ffa-eb11-4de5-9ae8-a179cb99750c@intel.com/
Mainly, x86 maintainers prefer imperative tone and references such as
"previous commit" can be confusing sometimes.
> Adjust USER_PTR_MAX if LAM enabled, allowing tag bits to be set for
> userspace pointers. The value for the constant is defined in a way to
> avoid overflow compiler warning on 32-bit config.
>
> [1] https://download.vusec.net/papers/slam_sp24.pdf
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
> ---
> arch/x86/Kconfig | 1 -
> arch/x86/kernel/cpu/common.c | 5 +----
> 2 files changed, 1 insertion(+), 5 deletions(-)
>
next prev parent reply other threads:[~2025-07-09 5:32 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-07 8:03 [PATCHv9 00/16] x86: Enable Linear Address Space Separation support Kirill A. Shutemov
2025-07-07 8:03 ` [PATCHv9 01/16] x86/cpu: Enumerate the LASS feature bits Kirill A. Shutemov
2025-07-07 8:03 ` [PATCHv9 02/16] x86/alternatives: Disable LASS when patching kernel alternatives Kirill A. Shutemov
2025-07-09 1:08 ` Sohil Mehta
2025-07-09 9:35 ` Kirill A. Shutemov
2025-07-09 16:58 ` Dave Hansen
2025-07-25 2:35 ` Sohil Mehta
2025-07-28 19:11 ` David Laight
2025-07-28 19:28 ` H. Peter Anvin
2025-07-28 19:38 ` David Laight
2025-08-01 0:15 ` Sohil Mehta
2025-07-07 8:03 ` [PATCHv9 03/16] x86/cpu: Set LASS CR4 bit as pinning sensitive Kirill A. Shutemov
2025-07-07 8:03 ` [PATCHv9 04/16] x86/cpu: Defer CR pinning setup until core initcall Kirill A. Shutemov
2025-07-09 1:19 ` Sohil Mehta
2025-07-09 9:38 ` Kirill A. Shutemov
2025-07-09 17:00 ` Dave Hansen
2025-07-31 23:45 ` Sohil Mehta
2025-08-01 0:01 ` Dave Hansen
2025-08-01 4:43 ` Sohil Mehta
2025-08-01 14:22 ` Dave Hansen
2025-08-02 18:51 ` Kees Cook
2025-08-04 6:55 ` H. Peter Anvin
2025-07-07 8:03 ` [PATCHv9 05/16] efi: Disable LASS around set_virtual_address_map() EFI call Kirill A. Shutemov
2025-07-09 1:27 ` Sohil Mehta
2025-07-07 8:03 ` [PATCHv9 06/16] x86/vsyscall: Do not require X86_PF_INSTR to emulate vsyscall Kirill A. Shutemov
2025-07-07 8:03 ` [PATCHv9 07/16] x86/vsyscall: Reorganize the #PF emulation code Kirill A. Shutemov
2025-07-07 8:03 ` [PATCHv9 08/16] x86/traps: Consolidate user fixups in exc_general_protection() Kirill A. Shutemov
2025-07-07 8:03 ` [PATCHv9 09/16] x86/vsyscall: Add vsyscall emulation for #GP Kirill A. Shutemov
2025-07-07 8:03 ` [PATCHv9 10/16] x86/vsyscall: Disable LASS if vsyscall mode is set to EMULATE Kirill A. Shutemov
2025-07-07 8:03 ` [PATCHv9 11/16] x86/traps: Communicate a LASS violation in #GP message Kirill A. Shutemov
2025-07-09 2:40 ` Sohil Mehta
2025-07-09 9:31 ` Kirill A. Shutemov
2025-07-09 9:36 ` Geert Uytterhoeven
2025-07-09 9:51 ` Kirill A. Shutemov
2025-07-07 8:03 ` [PATCHv9 12/16] x86/traps: Generalize #GP address decode and hint code Kirill A. Shutemov
2025-07-09 4:59 ` Sohil Mehta
2025-07-07 8:03 ` [PATCHv9 13/16] x86/traps: Handle LASS thrown #SS Kirill A. Shutemov
2025-07-09 5:12 ` Sohil Mehta
2025-07-09 10:38 ` Kirill A. Shutemov
2025-07-11 1:22 ` Sohil Mehta
2025-07-11 1:23 ` Sohil Mehta
2025-07-07 8:03 ` [PATCHv9 14/16] x86/cpu: Enable LASS during CPU initialization Kirill A. Shutemov
2025-07-07 8:03 ` [PATCHv9 15/16] x86/cpu: Make LAM depend on LASS Kirill A. Shutemov
2025-07-07 8:03 ` [PATCHv9 16/16] x86: Re-enable Linear Address Masking Kirill A. Shutemov
2025-07-09 5:31 ` Sohil Mehta [this message]
2025-07-09 11:00 ` Kirill A. Shutemov
2025-07-11 0:42 ` Sohil Mehta
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