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 D031423CE; Thu, 11 Jul 2024 01:24:40 +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=1720661084; cv=none; b=tLiu9PRhzkWD3JY2PyiNg/mlFmg2goudIBLpYkDasv/jucKSPNsyMDdX+vKcxYPBstSqKUGZy6Liw5DUSwHKSXXlV7QAhWa10uZ/16slEWfaVh7gSVCe7hv/B1w7+KgZ8N5GTZS37IlsTzVn2VipbZzJaGej2OKv2scZdtAcZQY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720661084; c=relaxed/simple; bh=WqUc+50yatqec/bDZPWg223qG82aa7ffR9EbPqWYqiE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NcpihtUB1xp/nUrmopkys0xrhpOSGuVpKac/gMXJ9CrhZ8AD2cIW48rqelNEgFv/pJiaE1kqLMuOVXK97yyJz3LzH0Z+dK/mSRMVs+7y8jt30DpvBITyp2xR3lz2etUIPTxZXccQB6Dl2ZMnX5ynVaNAfEGDc7jAGe0cHNK3OX0= 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=iUx4xrVf; 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="iUx4xrVf" Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTP id 3DF3E40E0206; Thu, 11 Jul 2024 01:24:37 +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 bZpwJXXJsqwJ; Thu, 11 Jul 2024 01:24:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=alien8; t=1720661072; bh=0ivUAjF+gH7cy3ad9SGegCyTH8sP11rPRTgqRJ5uBdE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=iUx4xrVfYT6hRqeHWPrTHUQNQvN7/SsR9BrcwyDOxS/pZGAbDkbTQSPBY4U9khXoO L/yMcukpwPEli97wKwnyxu41q3pK+cFpMz/gOGFcoh5PleAvuqE+7ceaFmh0eHRfC9 RBgtlSII3GbPGP5551p5hzWHej9gFKKu/U8YbV96OZavc9f2+Wi3tHLa2XZ45srCDM grXPnXvmUROV+0T3xSGubGq2ntBWtBsC5MabrFeiqe9rH0N0q+7+e8MXHWwBB9SFuf KGDbGS10RvPfuLZnAb8vk1Slr6AVN7URb109PSBB83bjL8kAVI1LonY3n3J8Ix+MYr BJftN1Z+8hTAKdoGjm/nwmg0xdCpCLOl7Wjt+XZeS29CppenSs/6m4H7t6Tp6PXf5E E/C20NPCHLlh/VFT880vmxXy5lbDR8bfO8vTUqz8dJH7/zDbgxL6GPBjOWuiB267uS 8cknKtl/8/BSSa87DA7RBzo3cm1wwMplZBDaCb2zqxT96Yo0/v1I45/PtjmUfYhvJ7 a64aSB8Eeodbb71qBWwZuAkcBvKtZzTEDW5VXkGS/MRSq3VnLQyRTcI2mQe3XG3BR2 ANH70NwERMx05P8cVwb2TD9Q17KTUiHD8Y3SXEFf66iRef2/C7/8NMOuXq1vWdyUHC VuGxSkmTcQ5A4ULzpwd9eSjE= Received: from zn.tnic (p5de8ee85.dip0.t-ipconnect.de [93.232.238.133]) (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 ESMTPSA id D09D440E0194; Thu, 11 Jul 2024 01:23:40 +0000 (UTC) Date: Thu, 11 Jul 2024 03:23:33 +0200 From: Borislav Petkov To: "Kirill A. Shutemov" Cc: Alexander Shishkin , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Peter Zijlstra , Ard Biesheuvel , "Paul E. McKenney" , Josh Poimboeuf , Xiongwei Song , Xin Li , "Mike Rapoport (IBM)" , Brijesh Singh , Michael Roth , Tony Luck , Alexey Kardashevskiy , Jonathan Corbet , Sohil Mehta , Ingo Molnar , Pawan Gupta , Daniel Sneddon , Kai Huang , Sandipan Das , Breno Leitao , Rick Edgecombe , Yian Chen , Alexei Starovoitov , Hou Tao , Juergen Gross , Vegard Nossum , Kees Cook , Eric Biggers , Jason Gunthorpe , "Masami Hiramatsu (Google)" , Andrew Morton , Luis Chamberlain , Yuntao Wang , Rasmus Villemoes , Christophe Leroy , Tejun Heo , Changbin Du , Huang Shijie , Geert Uytterhoeven , Namhyung Kim , Arnaldo Carvalho de Melo , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org Subject: Re: [PATCH v4 03/16] x86/alternatives: Disable LASS when patching kernel alternatives Message-ID: <20240711012333.GAZo80FU30_x77otP4@fat_crate.local> References: <20240710160655.3402786-1-alexander.shishkin@linux.intel.com> <20240710160655.3402786-4-alexander.shishkin@linux.intel.com> <20240710171836.GGZo7CbFJeZwLCZUAt@fat_crate.local> Precedence: bulk X-Mailing-List: linux-doc@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: On Thu, Jul 11, 2024 at 01:33:23AM +0300, Kirill A. Shutemov wrote: > Hm. Do we have text_poke() in hot path? > > Even if we do, I doubt flipping AC flag would make any performance > difference in context of all locking and TLB flushing we do in this > codepath. $ dmesg | grep text_poke | wc -l 237 In a silly guest. And regardless, we don't do unnecessary toggling of rFLAGS.AC. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette