From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.alien8.de (mail.alien8.de [65.109.113.108]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3F4582D5A0C; Wed, 22 Oct 2025 10:53:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=65.109.113.108 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761130406; cv=none; b=rF/bNsEWEO1BUDRzN3oBsonghq78fvg4idqzmPwdGFA5Y178sr9J1Oi1t2TYAt2M0jkQSqn0kdgvgLpf8i7OAD32e87Q4aI1U6EX4DG8c9x9p9T+GB8nR5pPDfa8bTS4mN+mssN2EdpUf8kDaNFCAsFk9VD4GNCPbDW30Isu4Oc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761130406; c=relaxed/simple; bh=wa9y6VC6nk+UaFLQfO+kcz1XNqHz+k0Uix1DKdIowCk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fgWmpOXFZHhe1yy/gDWcVAvW0J3hhBJfzGEa+DGucDtLsI0ZNXU5kbDNEHRG/koYi6yah/rwwdwbA+4JuWEJwCOcKDZ0mNzxMU0sQMQ2DFjVnNN9ZPaPg8+qrOKJUXCyGKnrlRizMMuaIUKgiYDvXjdMBK8cvfAkEikiA5evBjc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de; spf=pass smtp.mailfrom=alien8.de; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b=YYjqdxr0; arc=none smtp.client-ip=65.109.113.108 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=alien8.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=alien8.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (4096-bit key) header.d=alien8.de header.i=@alien8.de header.b="YYjqdxr0" Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTP id 8093B40E021B; Wed, 22 Oct 2025 10:53:21 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at mail.alien8.de Authentication-Results: mail.alien8.de (amavisd-new); dkim=pass (4096-bit key) header.d=alien8.de Received: from mail.alien8.de ([127.0.0.1]) by localhost (mail.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id UucJL8v8e33A; Wed, 22 Oct 2025 10:53:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=alien8; t=1761130396; bh=tCEcUCjHKCWYK1KKFqmFTHqeTyI6CWgRfbOF0mFOCRc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YYjqdxr0iJWnmBGWsR289Yr46Ha/4xxosopgB1DtB+anVpBZmGJpo0+LwXYMN5IxJ AryrzlrJjYuK27UEMFJmd8/WrEvrm0h3DEPNBpq4y8rsVvdzYP+Yw08rqgczR7CEuz ncnU0Xt/3QVtBXCJZzMNju1a/CW3izjiHbpGNTj3dfRpyrehVACrvkK0RVsbjdvmhi jmrX//NTjBB8AjJdYesDYcbFwbVSiHxZ1jbnKI2j5X/pDDYt7kl0eNmjQAiOZAbIKr 5fo8/wtfyvxSE4f8s5+6iXDprREY+3BtSUt594uNddfuk3n0cCVsip1pVKyNvcAG5X WEsTX67vOTcbDEwS0G5Ck3UTL4Bo3lPiWohPgq6SPVRLlN2MkDZnCaC+biVWPsxyK2 CfZ2TTuNhnaTTmmnOBKIHRTulYZ85cDjezkv2fyWOr1lmjztW4qnxt85l7wROADKAf sjpErQjdLwZJ+fF7p3ziO2G+iTrs3CTT+DlLk8ictJe78x+dTdhhkrXHY+Y5cwbkZN ko4VEZEISFW8U+8ExZyH4ECjiOH/nulbCZ/AYSynBAia6PcQGm4dwb4MqW2+vLEXjP 4BB3tA3dOZ+aK0nmaTzBAYteBQCo+yQnjdUQYnclNQtbHyjkapMuvuaSeXR9AgvA9/ P9TkY7gWgcJT/b0wzE7ZBPc8= Received: from zn.tnic (pd9530da1.dip0.t-ipconnect.de [217.83.13.161]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-256) server-digest SHA256) (No client certificate requested) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with UTF8SMTPSA id C26E240E0200; Wed, 22 Oct 2025 10:52:48 +0000 (UTC) Date: Wed, 22 Oct 2025 12:52:42 +0200 From: Borislav Petkov To: Peter Zijlstra Cc: Sohil Mehta , x86@kernel.org, Dave Hansen , Thomas Gleixner , Ingo Molnar , Jonathan Corbet , "H . Peter Anvin" , Andy Lutomirski , Josh Poimboeuf , Ard Biesheuvel , "Kirill A . Shutemov" , Xin Li , David Woodhouse , Sean Christopherson , Rick Edgecombe , Vegard Nossum , Andrew Cooper , David Laight , Randy Dunlap , Geert Uytterhoeven , Kees Cook , Tony Luck , Alexander Shishkin , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org Subject: Re: [PATCH v10 03/15] x86/alternatives: Disable LASS when patching kernel alternatives Message-ID: <20251022105242.GCaPi3eps1PdAWEXOh@fat_crate.local> References: <20251007065119.148605-1-sohil.mehta@intel.com> <20251007065119.148605-4-sohil.mehta@intel.com> <20251021200328.GMaPfnEDibnBrhNTmQ@fat_crate.local> <20251022082541.GL4067720@noisy.programming.kicks-ass.net> <20251022094019.GAaPimg3VCgRu6eELd@fat_crate.local> <20251022102253.GW3419281@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: linux-efi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20251022102253.GW3419281@noisy.programming.kicks-ass.net> On Wed, Oct 22, 2025 at 12:22:53PM +0200, Peter Zijlstra wrote: > 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. Yeah, makes sense. The second alternative with LASS sounds like the optimal thing. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette