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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B27ABC433ED for ; Tue, 18 May 2021 13:33:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 43D7A611AD for ; Tue, 18 May 2021 13:33:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 43D7A611AD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A54DB8E0028; Tue, 18 May 2021 09:33:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A05128E0023; Tue, 18 May 2021 09:33:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8B97D8E0028; Tue, 18 May 2021 09:33:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0064.hostedemail.com [216.40.44.64]) by kanga.kvack.org (Postfix) with ESMTP id 57B108E0023 for ; Tue, 18 May 2021 09:33:23 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id EC7614FEC for ; Tue, 18 May 2021 13:33:22 +0000 (UTC) X-FDA: 78154443444.21.9BAF267 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by imf01.hostedemail.com (Postfix) with ESMTP id E4C2A500152D for ; Tue, 18 May 2021 13:33:17 +0000 (UTC) IronPort-SDR: qWBr442ePcnQs08c5CuwHrGbzi2u529EAfAN+b415bqPcdG42b1D+ynEdiyTGDWDiZXohb56Zq eBORPYwQYhIQ== X-IronPort-AV: E=McAfee;i="6200,9189,9987"; a="180314165" X-IronPort-AV: E=Sophos;i="5.82,310,1613462400"; d="scan'208";a="180314165" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 May 2021 06:33:18 -0700 IronPort-SDR: JD1KVpOLoXzO9+IeWZmr5Vy+CCysqoXN/qIswodanwS1ndGx6ikR3RlmKh+B7FFgVag35gnd6F JHMYFcFN+NuQ== X-IronPort-AV: E=Sophos;i="5.82,310,1613462400"; d="scan'208";a="438664467" Received: from cmutgix-mobl.gar.corp.intel.com (HELO [10.249.254.195]) ([10.249.254.195]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 May 2021 06:33:16 -0700 Subject: Re: [Intel-gfx] [PATCH 4/4] i915: fix remap_io_sg to verify the pgprot To: Christoph Hellwig Cc: Serge Belyshev , Peter Zijlstra , Daniel Vetter , intel-gfx@lists.freedesktop.org, Chris Wilson , linux-mm@kvack.org, dri-devel@lists.freedesktop.org, Andrew Morton References: <20210326055505.1424432-1-hch@lst.de> <20210326055505.1424432-5-hch@lst.de> <87pmxqiry6.fsf@depni.sinp.msu.ru> <20210517123716.GD15150@lst.de> <87lf8dik15.fsf@depni.sinp.msu.ru> <20210517131137.GA19451@lst.de> <976fb38a-7780-6ca6-d602-a5f02c0938c9@linux.intel.com> <6adf9658-25b7-16ef-4b88-fa3911d06b74@linux.intel.com> <20210518132428.GD2617@lst.de> From: =?UTF-8?Q?Thomas_Hellstr=c3=b6m?= Message-ID: <114520ed-6d61-a2a1-b753-fb169ef6ecea@linux.intel.com> Date: Tue, 18 May 2021 15:33:14 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210518132428.GD2617@lst.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-Rspamd-Queue-Id: E4C2A500152D Authentication-Results: imf01.hostedemail.com; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=intel.com (policy=none); spf=none (imf01.hostedemail.com: domain of thomas.hellstrom@linux.intel.com has no SPF policy when checking 192.55.52.136) smtp.mailfrom=thomas.hellstrom@linux.intel.com X-Rspamd-Server: rspam04 X-Stat-Signature: 6rgxbq5zutu4bk8a8abqsq7zizreuyc8 X-HE-Tag: 1621344797-677743 Content-Transfer-Encoding: quoted-printable 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: On 5/18/21 3:24 PM, Christoph Hellwig wrote: > On Tue, May 18, 2021 at 08:46:44AM +0200, Thomas Hellstr=C3=B6m wrote: >> And worse, if we prefault a user-space buffer object map using >> remap_io_sg() and then zap some ptes using madvise(), the next time th= ose >> ptes are accessed, we'd trigger a new call to remap_io_sg() which woul= d now >> find already populated ptes. While the old code looks to just silently >> overwrite those, it looks like the new code would BUG in remap_pte_ran= ge()? > How can you zap the PTEs using madvise? Hmm, that's not possible with VM_PFNMAP. My bad. Should be OK then. /Thomas