From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 318CEC83038 for ; Wed, 2 Jul 2025 17:11:58 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A0D3B6B00C7; Wed, 2 Jul 2025 13:11:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9BDD26B00C9; Wed, 2 Jul 2025 13:11:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8AC8A6B00CA; Wed, 2 Jul 2025 13:11:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 76F236B00C7 for ; Wed, 2 Jul 2025 13:11:57 -0400 (EDT) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 21448C0345 for ; Wed, 2 Jul 2025 17:11:57 +0000 (UTC) X-FDA: 83619967074.20.460854B Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) by imf26.hostedemail.com (Postfix) with ESMTP id AE808140006 for ; Wed, 2 Jul 2025 17:11:53 +0000 (UTC) Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=zytor.com header.s=2025062101 header.b=Hjeif9o6; dmarc=pass (policy=none) header.from=zytor.com; spf=pass (imf26.hostedemail.com: domain of hpa@zytor.com designates 198.137.202.136 as permitted sender) smtp.mailfrom=hpa@zytor.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1751476314; a=rsa-sha256; cv=none; b=DTDpzghWl8s5irtruGu5NpvKRmo7UQVGJMlA+odw5G/xCsH/XIDK/7zYXiTfO9BcWJSHsv 28YUXjzL8fJcNKTPj4Pcg+0lu3c0NOvyZVtIy5GdYybsv3s7IxjQURkiJiQhydrLdITQHy 5LmvBFmNa2VcxcC1XNktkjF0lkh2Juw= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=pass header.d=zytor.com header.s=2025062101 header.b=Hjeif9o6; dmarc=pass (policy=none) header.from=zytor.com; spf=pass (imf26.hostedemail.com: domain of hpa@zytor.com designates 198.137.202.136 as permitted sender) smtp.mailfrom=hpa@zytor.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1751476314; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=kNg/g5ljt7nOKC7WSIlXA9rxszXt9xhQVAALjJf2IYA=; b=3KXdmOL4ZvrkmOP6UEDjLTByLOz1vKGT1iGyw7zfGWFDJZU2ijGrWQcv/JkQoGf6uLoFfA q/3QixmEyOgQd2/8kmKchy9GuWaYQDyinSs3NppfSRP3xzs98Qgyh1nXH8fJzIyNTRnFyY KFCh+CWxAwFCKzZfzpPS8cQpP1dVcqA= Received: from [127.0.0.1] (c-76-133-66-138.hsd1.ca.comcast.net [76.133.66.138]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 562HB06T746462 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Wed, 2 Jul 2025 10:11:00 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 562HB06T746462 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2025062101; t=1751476264; bh=kNg/g5ljt7nOKC7WSIlXA9rxszXt9xhQVAALjJf2IYA=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=Hjeif9o6GyWihjdMk5Hc7VaQ50WO7uLC7HzqhSUd/55fcAhpCapeTKEfyaM12BtdP gz0aCmWronOAjPiG8PFmpiKZLUUgms/EB+TluNZQGC0t+htsKumiZnB19lwpJm1lxd XipDNLBIhgIcXXTJhTEB18mKX4956sMHLlVhGHa3qP/+Tiib0YjFSP0gCwRtwX3qxg H7VtggQXp62qQ8Jqi8JutBAsT2f6+dw6WmZeAyLVZxFy8adB2lc64rl5Z9r44BAKHM PNEhOVUevuJ8BvcGjrd/U9juT59nGLE4xRb5fFJw+aOnp+kFWiq/gGuEEHgXZCkIF+ GnxnsUEIyZMbQ== Date: Wed, 02 Jul 2025 10:10:58 -0700 From: "H. Peter Anvin" To: "Kirill A. Shutemov" CC: Sohil Mehta , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Peter Zijlstra , Ard Biesheuvel , "Paul E. McKenney" , Josh Poimboeuf , Xiongwei Song , Xin Li , "Mike Rapoport (IBM)" , Brijesh Singh , Michael Roth , Tony Luck , Alexey Kardashevskiy , Alexander Shishkin , Jonathan Corbet , Ingo Molnar , Pawan Gupta , Daniel Sneddon , Kai Huang , Sandipan Das , Breno Leitao , Rick Edgecombe , 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, linux-mm@kvack.org Subject: Re: [PATCHv8 14/17] x86/traps: Handle LASS thrown #SS User-Agent: K-9 Mail for Android In-Reply-To: <6vihhfk5z33nrpy53ck2c6tkscjas4fhi6hqorenknbnjo4k3j@ywybd4obx76m> References: <20250701095849.2360685-1-kirill.shutemov@linux.intel.com> <20250701095849.2360685-15-kirill.shutemov@linux.intel.com> <95dc18fd-73b0-4019-92d2-c0e6aaf22c96@intel.com> <4DE45AFD-C1E0-4FB8-BE01-44A72C5C6E1E@zytor.com> <5q2zbkzyjknusd3feqolycqialetqfe52yfyzasnr6zp24pmej@4cg2r2hi4pf2> <6vihhfk5z33nrpy53ck2c6tkscjas4fhi6hqorenknbnjo4k3j@ywybd4obx76m> Message-ID: <498F5590-2711-47E9-A58F-CC9EB41D71AA@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: AE808140006 X-Stat-Signature: xa3crukt5ehox88aatmrqrsoa4tzj4td X-HE-Tag: 1751476313-732014 X-HE-Meta: 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 0mPPuSRx Yt9MJZK+KiB5HN13zsxp4KUI1UtMLxrfSWr2vbQf4q+NaRFyZJOdbYp49lpfxXsgf4zWwD3SdX4DZfX6Yaj0472uzHry7mqUbUFKuFMs0lkc3FWcsRA8RuyZ7816iG2yeTm4LkRlRJMqP7eol5fhGeHBm1rEkvD6s2qFZpBlLxkojzMLCBtYOZ943opC/ScB+uNoPH3ZDpR/E/OJM6CboqH/LkZOqpOXj8dpyTCkgyEZZXkrpNLHaFvZbsMnr3oWX5lhFF244eQ3HAyryqp+GOUAIOxWtNTiduV3tOisq6593HGcFcn1yjbyI/xwMjmHl04inSzAROJPUoAeCFo6nkjYdJhnvde+V+QuIAPoBNOEGqo6430GfsG/0zOa8rQ48sZWyOPtStS7o4LvXWhyW4u5eFlC4ajcjkT29 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On July 2, 2025 7:47:30 AM PDT, "Kirill A=2E Shutemov" wrote: >On Wed, Jul 02, 2025 at 07:37:12AM -0700, H=2E Peter Anvin wrote: >> A LASS violation of any kind in the kernel (unless handled by fixup, >> including user access fixup) ought to be fatal, correct? > >Yes, LASS violation is fatal for !user_mode(regs), unless addressed by >fixups=2E > >For user_mode(regs), emulate_vsyscall_gp() is the notable exception=2E > Note also that for FRED we can have separate kernel and user space paths b= asically "for free"=2E I'm not sure if we do that yet (if the infrastructur= e is there), but we could=2E=20 Not that it matters for this case=2E This is a slow path=2E