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Date: Wed, 22 Oct 2025 12:22:53 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Borislav Petkov <bp@alien8.de>
Cc: Sohil Mehta <sohil.mehta@intel.com>, x86@kernel.org,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Jonathan Corbet <corbet@lwn.net>,
	"H . Peter Anvin" <hpa@zytor.com>,
	Andy Lutomirski <luto@kernel.org>,
	Josh Poimboeuf <jpoimboe@kernel.org>,
	Ard Biesheuvel <ardb@kernel.org>,
	"Kirill A . Shutemov" <kas@kernel.org>, Xin Li <xin@zytor.com>,
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	linux-efi@vger.kernel.org
Subject: Re: [PATCH v10 03/15] x86/alternatives: Disable LASS when patching
 kernel alternatives
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References: <20251007065119.148605-1-sohil.mehta@intel.com>
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On Wed, Oct 22, 2025 at 11:40:19AM +0200, Borislav Petkov wrote:

> > But that's not the same, stac() and clac() are FEATURE_SMAP, these are
> > FEATURE_LASS.
> 
> So?

That's confusing. Just keep them separate alternatives.

> Are you thinking of toggling features and then something else getting disabled
> in the process?

I'm thinking that machines without LASS don't need the clac/stac in
these places. And when reading the asm, the FEATURE_LASS is a clue.