From: Sohil Mehta <sohil.mehta@intel.com>
To: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
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Subject: Re: [PATCH v10 01/15] x86/cpu: Enumerate the LASS feature bits
Date: Tue, 7 Oct 2025 13:49:12 -0700 [thread overview]
Message-ID: <e82b48b9-5566-4bf2-9b9e-ee529d59e9b5@intel.com> (raw)
In-Reply-To: <47fb7efd89698f46a305ca446d0e4471d1f24fbb.camel@intel.com>
On 10/7/2025 11:19 AM, Edgecombe, Rick P wrote:
>> LASS provides the same mode-based protections as paging but without
>> traversing the paging structures. Because the protections are enforced
>> pre-paging, an attacker will not be able to derive paging-based timing
>
> Nit: pre-page walk maybe? Otherwise it could sound like before paging is enabled
> during boot.
>
How about: ... protections are enforced prior to page walks, an ...
>>
>> +config X86_DISABLED_FEATURE_LASS
>> + def_bool y
>> + depends on X86_32
>> +
>
> All the other ones in the file are !X86_64. Why do this one X86_32?
>
The double negation (DISABLED and !X86_64) was harder to follow when
this was initially posted.
https://lore.kernel.org/lkml/73796800-819b-4433-b0ef-db852336d7a4@zytor.com/
https://lore.kernel.org/lkml/756e93a2-7e42-4323-ae21-a5437e71148e@infradead.org/
I don't have a strong preference. I guess the inconsistency makes it
confusing as well. Will change it back to !X86_64 unless Xin objects.
next prev parent reply other threads:[~2025-10-07 20:49 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-07 6:51 [PATCH v10 00/15] x86: Enable Linear Address Space Separation support Sohil Mehta
2025-10-07 6:51 ` [PATCH v10 01/15] x86/cpu: Enumerate the LASS feature bits Sohil Mehta
2025-10-07 18:19 ` Edgecombe, Rick P
2025-10-07 18:28 ` Dave Hansen
2025-10-07 20:20 ` Sohil Mehta
2025-10-07 20:38 ` Edgecombe, Rick P
2025-10-07 20:53 ` Sohil Mehta
2025-10-16 3:10 ` H. Peter Anvin
2025-10-07 20:49 ` Sohil Mehta [this message]
2025-10-07 23:16 ` Xin Li
2025-10-08 16:00 ` Edgecombe, Rick P
2025-10-16 15:35 ` Borislav Petkov
2025-10-21 18:03 ` Sohil Mehta
2025-10-07 6:51 ` [PATCH v10 02/15] x86/asm: Introduce inline memcpy and memset Sohil Mehta
2025-10-21 12:47 ` Borislav Petkov
2025-10-21 13:48 ` David Laight
2025-10-21 18:06 ` Sohil Mehta
2025-10-07 6:51 ` [PATCH v10 03/15] x86/alternatives: Disable LASS when patching kernel alternatives Sohil Mehta
2025-10-07 16:55 ` Edgecombe, Rick P
2025-10-07 22:28 ` Sohil Mehta
2025-10-08 16:22 ` Edgecombe, Rick P
2025-10-10 17:10 ` Sohil Mehta
2025-10-21 20:03 ` Borislav Petkov
2025-10-21 20:55 ` Sohil Mehta
2025-10-22 9:56 ` Borislav Petkov
2025-10-22 19:49 ` Sohil Mehta
2025-10-22 20:03 ` Luck, Tony
2025-10-22 8:25 ` Peter Zijlstra
2025-10-22 9:40 ` Borislav Petkov
2025-10-22 10:22 ` Peter Zijlstra
2025-10-22 10:52 ` Borislav Petkov
2025-10-07 6:51 ` [PATCH v10 04/15] x86/cpu: Set LASS CR4 bit as pinning sensitive Sohil Mehta
2025-10-07 18:24 ` Edgecombe, Rick P
2025-10-07 23:11 ` Sohil Mehta
2025-10-08 16:52 ` Edgecombe, Rick P
2025-10-10 19:03 ` Sohil Mehta
2025-10-07 6:51 ` [PATCH v10 05/15] x86/cpu: Defer CR pinning enforcement until late_initcall() Sohil Mehta
2025-10-07 17:23 ` Edgecombe, Rick P
2025-10-07 23:05 ` Sohil Mehta
2025-10-08 17:36 ` Edgecombe, Rick P
2025-10-10 20:45 ` Sohil Mehta
2025-10-15 21:17 ` Sohil Mehta
2025-10-17 19:28 ` Sohil Mehta
2025-10-07 6:51 ` [PATCH v10 06/15] x86/efi: Disable LASS while mapping the EFI runtime services Sohil Mehta
2025-10-07 6:51 ` [PATCH v10 07/15] x86/kexec: Disable LASS during relocate kernel Sohil Mehta
2025-10-07 17:43 ` Edgecombe, Rick P
2025-10-07 22:33 ` Sohil Mehta
2025-10-07 6:51 ` [PATCH v10 08/15] x86/vsyscall: Reorganize the page fault emulation code Sohil Mehta
2025-10-07 18:37 ` Edgecombe, Rick P
2025-10-07 18:48 ` Dave Hansen
2025-10-07 19:53 ` Edgecombe, Rick P
2025-10-07 22:52 ` Sohil Mehta
2025-10-08 17:42 ` Edgecombe, Rick P
2025-10-30 16:58 ` Andy Lutomirski
2025-10-30 17:22 ` H. Peter Anvin
2025-10-30 17:35 ` Andy Lutomirski
2025-10-30 19:28 ` Sohil Mehta
2025-10-30 21:37 ` David Laight
2025-10-07 6:51 ` [PATCH v10 09/15] x86/traps: Consolidate user fixups in exc_general_protection() Sohil Mehta
2025-10-07 17:46 ` Edgecombe, Rick P
2025-10-07 22:41 ` Sohil Mehta
2025-10-08 17:43 ` Edgecombe, Rick P
2025-10-07 6:51 ` [PATCH v10 10/15] x86/vsyscall: Add vsyscall emulation for #GP Sohil Mehta
2025-10-07 6:51 ` [PATCH v10 11/15] x86/vsyscall: Disable LASS if vsyscall mode is set to EMULATE Sohil Mehta
2025-10-07 18:43 ` Edgecombe, Rick P
2025-10-07 6:51 ` [PATCH v10 12/15] x86/traps: Communicate a LASS violation in #GP message Sohil Mehta
2025-10-07 18:07 ` Edgecombe, Rick P
2025-10-07 6:51 ` [PATCH v10 13/15] x86/traps: Generalize #GP address decode and hint code Sohil Mehta
2025-10-07 18:43 ` Edgecombe, Rick P
2025-10-07 6:51 ` [PATCH v10 14/15] x86/traps: Provide additional hints for a kernel stack segment fault Sohil Mehta
2025-10-07 6:51 ` [PATCH v10 15/15] x86/cpu: Enable LASS by default during CPU initialization Sohil Mehta
2025-10-07 18:42 ` Edgecombe, Rick P
2025-10-07 16:23 ` [PATCH v10 00/15] x86: Enable Linear Address Space Separation support Edgecombe, Rick P
2025-10-17 19:52 ` Sohil Mehta
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