linux-kernel - Re: [PATCH 0/3] x86: Extend LASS support to EFI configurations

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Message-ID: <98ca1e1a-4bc7-4a6c-b587-b6c2a60db7bc@intel.com>
Date: Fri, 12 Dec 2025 16:21:06 -0800
From: Sohil Mehta <sohil.mehta@...el.com>
To: Ard Biesheuvel <ardb@...nel.org>, "H. Peter Anvin" <hpa@...or.com>
CC: <x86@...nel.org>, Dave Hansen <dave.hansen@...ux.intel.com>, "Thomas
 Gleixner" <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, "Borislav
 Petkov" <bp@...en8.de>, Andy Lutomirski <luto@...nel.org>, Peter Zijlstra
	<peterz@...radead.org>, Kiryl Shutsemau <kas@...nel.org>, Rick Edgecombe
	<rick.p.edgecombe@...el.com>, Andrew Cooper <andrew.cooper3@...rix.com>,
	"Tony Luck" <tony.luck@...el.com>, Alexander Shishkin
	<alexander.shishkin@...ux.intel.com>, <linux-kernel@...r.kernel.org>,
	<linux-efi@...r.kernel.org>
Subject: Re: [PATCH 0/3] x86: Extend LASS support to EFI configurations

On 12/4/2025 11:58 AM, Ard Biesheuvel wrote:
> On Thu, 4 Dec 2025 at 20:51, H. Peter Anvin <hpa@...or.com> wrote:
>> 
>> But your underlying assumption is that disabling LASS around EFI
>> calls is a problem. It isn't, because the efi_mm has explicitly
>> unmapped any memory EFI isn't allowed to touch. In other words, we
>> are already doing the equivalent of LASS "manually."
>> 
> 
> I must have misunderstood then - there was some pushback on this
> IIRC but if en/disabling LASS is fine then sure.
Thanks for the feedback! I'll leave the patches as-is then and wait for
additional comments.