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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 51181C56201 for ; Wed, 21 Oct 2020 19:24:23 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B07F92417E for ; Wed, 21 Oct 2020 19:24:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="UcRTFA71" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B07F92417E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id CB6C66F4B6; Wed, 21 Oct 2020 19:24:21 +0000 (UTC) Received: from mail-ot1-x343.google.com (mail-ot1-x343.google.com [IPv6:2607:f8b0:4864:20::343]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2B4466F4B4 for ; Wed, 21 Oct 2020 19:24:20 +0000 (UTC) Received: by mail-ot1-x343.google.com with SMTP id l4so2891745ota.7 for ; Wed, 21 Oct 2020 12:24:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=sYM9cUyMSOj9mKCWCe707+J8b20m45BOShUil5OYiuY=; b=UcRTFA71oa+ZohVvqr5nTk2VrlQIDJZuL8YbFFB6slZWA8umJ/bN/qbSbMlqTB7z0q bIxgy64Kmi9zqOgOlY5HP3Sd823hLvIZ4IY3eeEDdvu0znOIz4Dey+GMkJlQfrWVVWss 6QNEH9JVNXJd4SlM1j+HDRzTJLUTR8870k28s= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=sYM9cUyMSOj9mKCWCe707+J8b20m45BOShUil5OYiuY=; b=R/KZ95fXvePqcO8UPgrfiBwZXUDoKMrPUysnb7psZ58EDPqS8x2uQWXkAPHoZcN81x fibaHKDNmk/zNEzoyrwMUMJaggNvFGJdcm8tjVkPU8RU24/oiVo9pjd2SQyMs/xPhYDy D2tiAnKrxODpN5IqNybZdhRGB05MasMq7Psv3HgjTQPqwZnUsAEMhVzTiJvh3/LYD1/v bPogWJavHn7X2KhaVkasJsA86vHBVVujUuXK+3fOHXD0AUctKsV5lhaviykUV8W3jH3b C7gnbG5cE9oZgc8tAhjo5HeaVfSM/1md52f27s5ANK7hZuKnqx6PFzhesLmqRAMJK0js FUZg== X-Gm-Message-State: AOAM5338+sTvU+RK3fNcjk0Pc3OEEbcqLTtcgt0sv8qwyUBRM5fLMT2i Gl06zfce9nZuiEFTbJr97KJ0fNw3ewKGQI/NKiTNLQ== X-Google-Smtp-Source: ABdhPJwJGiQE46eBJclvgjHXJJ+j87WJ+7cjHqpCSH7v0fZi8HkcRkC+gln/SdoBFVWEgA88/UYBf7mOSQSqgr0L7bk= X-Received: by 2002:a05:6830:1647:: with SMTP id h7mr3877970otr.281.1603308259478; Wed, 21 Oct 2020 12:24:19 -0700 (PDT) MIME-Version: 1.0 References: <20201021085655.1192025-1-daniel.vetter@ffwll.ch> <20201021085655.1192025-13-daniel.vetter@ffwll.ch> <20201021125030.GK36674@ziepe.ca> <20201021151352.GL36674@ziepe.ca> <20201021163702.GM36674@ziepe.ca> In-Reply-To: <20201021163702.GM36674@ziepe.ca> From: Daniel Vetter Date: Wed, 21 Oct 2020 21:24:08 +0200 Message-ID: Subject: Re: [PATCH v3 12/16] PCI: Obey iomem restrictions for procfs mmap To: Jason Gunthorpe X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-s390 , linux-samsung-soc , Jan Kara , Kees Cook , KVM list , Daniel Vetter , John Hubbard , LKML , DRI Development , Linux MM , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Linux PCI , Bjorn Helgaas , Daniel Vetter , Dan Williams , Andrew Morton , Linux ARM , "open list:DMA BUFFER SHARING FRAMEWORK" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Wed, Oct 21, 2020 at 6:37 PM Jason Gunthorpe wrote: > > On Wed, Oct 21, 2020 at 05:54:54PM +0200, Daniel Vetter wrote: > > > The trouble is that io_remap_pfn adjust vma->pgoff, so we'd need to > > split that. So ideally ->mmap would never set up any ptes. > > /dev/mem makes pgoff == pfn so it doesn't get changed by remap. > > pgoff doesn't get touched for MAP_SHARED either, so there are other > users that could work like this - eg anyone mmaping IO memory is > probably OK. I was more generally thinking for io_remap_pfn_users because of the mkwrite use-case we might have in fbdev emulation in drm. > > I guess one option would be if remap_pfn_range would steal the > > vma->vm_ops pointer for itself, then it could set up the correct > > ->install_ptes hook. But there's tons of callers for that, so not sure > > that's a bright idea. > > The caller has to check that the mapping is still live, and I think > hold a lock across the remap? Auto-defering it doesn't seem feasible. Right auto-defering reopens the race, so making this work automatically is a bit much. I guess just splitting this into a setup/install part and then doing the install of all the ptes at first fault should be good enough. We don't really need a new install_pages for that, just an io_remap_pfn_range that's split in two parts. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel