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 42592C433B4 for ; Wed, 19 May 2021 05:52:15 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B201661244 for ; Wed, 19 May 2021 05:52:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B201661244 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 4588D6B0092; Wed, 19 May 2021 01:52:14 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 407846B0093; Wed, 19 May 2021 01:52:14 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2A89E6B0095; Wed, 19 May 2021 01:52:14 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0219.hostedemail.com [216.40.44.219]) by kanga.kvack.org (Postfix) with ESMTP id F0A026B0092 for ; Wed, 19 May 2021 01:52:13 -0400 (EDT) Received: from smtpin36.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 8E4D3612F for ; Wed, 19 May 2021 05:52:13 +0000 (UTC) X-FDA: 78156910146.36.7C88559 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by imf18.hostedemail.com (Postfix) with ESMTP id 7E61820007D7 for ; Wed, 19 May 2021 05:52:10 +0000 (UTC) IronPort-SDR: S99QxjH2Nv4d9WVKyoO7n0Cy/Cb4F18hitppZ+GfAQdrRgEDdeW5BflHZ7OyvNMX8E3sVytm4c 0XLiQrxoq6xQ== X-IronPort-AV: E=McAfee;i="6200,9189,9988"; a="180499148" X-IronPort-AV: E=Sophos;i="5.82,312,1613462400"; d="scan'208";a="180499148" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 May 2021 22:52:00 -0700 IronPort-SDR: bsmntiYDgDjdyOsRgCHKijC45Hwgr2cG1dWGAJjSezNCb8JW+Qm4sMcYZIyvemyybZIoOT7s80 qJZK2t3ie0OQ== X-IronPort-AV: E=Sophos;i="5.82,312,1613462400"; d="scan'208";a="627483643" Received: from clanggaa-mobl1.ger.corp.intel.com (HELO [10.249.254.222]) ([10.249.254.222]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 May 2021 22:51:58 -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> <20210518132333.GC2617@lst.de> From: =?UTF-8?Q?Thomas_Hellstr=c3=b6m?= Message-ID: <1d6cc36a-cce9-92d3-4ca9-67d1450232a3@linux.intel.com> Date: Wed, 19 May 2021 07:51:55 +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: <20210518132333.GC2617@lst.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-Rspamd-Queue-Id: 7E61820007D7 Authentication-Results: imf18.hostedemail.com; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=intel.com (policy=none); spf=none (imf18.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: qnejbq9uaywcb89q57ky8e5eckzouq1q X-HE-Tag: 1621403530-627421 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 3:23 PM, Christoph Hellwig wrote: > On Mon, May 17, 2021 at 11:46:35PM +0200, Thomas Hellstr=C3=B6m wrote: >> Apart from the caching aliasing Mattew brought up, doesn't the >> remap_pfn_range_xxx() family require the mmap_sem held in write mode s= ince >> it modifies the vma structure? remap_io_sg() is called from the fault >> handler with the mmap_sem held in read mode only. > Only for vma->vm_flags, and remap_sg already asserts all the interestin= g > flags are set, although it does not assert VM_IO. > > We could move the assignment out of remap_pfn_range_notrack and > into remap_pfn_range and just assert that the proper flags are set, > though. That to me sounds like a way forward. It sound like in general a gpu=20 prefaulting helper that in the long run also supports faulting huge ptes=20 is desired also by TTM. Although it looks like that BUG_ON() I pointed=20 out was hit anyway.... /Thomas