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=-14.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 AF211C433DB for ; Thu, 25 Mar 2021 21:36:19 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 4A2ED61A1E for ; Thu, 25 Mar 2021 21:36:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4A2ED61A1E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Cc:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=umpp9LFrjpE5zXW7MwLLkE9vzte6AVG4poEW9a8XVfY=; b=ECaKGA3TzKP4/gkLnau45Xn2O XzvDVhf0YIJwn66dB0UqVqS25i0j1xhC/aoc6Xj2QROXuNOG0VcPOrA5Ldg0va4uaRNgPbMbK9bLU piZ4VIeuCTLR6ttpZDK7bONbyXD4hLjPchL/MzMjYtVfcjhyFeyMjn64xpKBkpgX33EC7aMiOMqSZ iVyi5hy+jTQg7+pem50KelUa1Ct99x/l3T48Ep/DZZ+2Dna07HY2JUzql1RdFNLRhsq5tsTM2UkOb 8N4WOtmrnHOyzzGpxtfye6omAqAKO/TvX19vE+lzVDEM02cGl3xUhuf0+3Oe0HYIWCPuSyoMKVPIt fD09QmRyQ==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lPXcE-002Dqe-Nb; Thu, 25 Mar 2021 21:34:06 +0000 Received: from mail-wr1-x433.google.com ([2a00:1450:4864:20::433]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lPXc8-002Dpg-Dn for linux-arm-kernel@lists.infradead.org; Thu, 25 Mar 2021 21:34:03 +0000 Received: by mail-wr1-x433.google.com with SMTP id x7so3702693wrw.10 for ; Thu, 25 Mar 2021 14:33:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=date:from:to:subject:message-id:mail-followup-to:references :mime-version:content-disposition:in-reply-to; bh=TXHI1OxX+D4iSzKCuoMMss3yjiQz/+KLKVrP99q3G2I=; b=frvH/QuNUnODqvtDdusaUFppblhOygLUWsC1ixB43GNG2Cc+yxM2WFbRWpgjN4Ju8Y 95PeIsuDNMn98oqagJ3ef1Nu2yOkiL1vvMi/6inWwQyeTtLH5DD3GrBLCXNufjRYGMCK r/gFSHALeS9GIhicmr/nrrhcB3MijIi/RQZtU= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:subject:message-id:mail-followup-to :references:mime-version:content-disposition:in-reply-to; bh=TXHI1OxX+D4iSzKCuoMMss3yjiQz/+KLKVrP99q3G2I=; b=GoS0JTXtOK0Z+1qN13l8ofZVgkl6NLcqCNePo72zlwbnvccedXE816x4wp5kHWIikC Pslb1ZAg2bCoX6kC1bLnNT4DkvUKC88XwkhMVy6KWvvHreOEBK3UaSFSyPDJkv+lJgZ0 NpdG1jPQdtPL2jZ4CgEurMvzW3NiYf3G8Cs54ItLx2FGM0HojCVpvlgBmZl3eR1ef/Fh DViiQZCIWLbQju1OiiOQuW0y4DcCLA+cOweMlkuq/Tzx8QSRy7/OWqGDE6/7X8RIJBdL LysY87CbZOSNzcm3yzdPwFFs54Ra8N54sLD9ChMbTu6Vs6gHAHsC1giUsMKHtGGpVpfc +0LQ== X-Gm-Message-State: AOAM531xKdhT9uvaNBxDNvCCIepp2CCCxvqOLwM/ZU4I0WIGuGp5VdBt vkC07mbqtgwHwt6eU7EabP2v3ar72fc9zJHH X-Google-Smtp-Source: ABdhPJwn8UAApYENGs0EsRiOl6kaa4IOv1NsIwYwvHs5ZhbA+T+EIOa3Ak0sCs/YbuNvp+I4gerYDg== X-Received: by 2002:adf:e8c9:: with SMTP id k9mr10992298wrn.315.1616708036367; Thu, 25 Mar 2021 14:33:56 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id x13sm1115693wmp.39.2021.03.25.14.33.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Mar 2021 14:33:55 -0700 (PDT) Date: Thu, 25 Mar 2021 22:33:53 +0100 From: Daniel Vetter To: Jason Gunthorpe , DRI Development , LKML , kvm@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-media@vger.kernel.org, 3pvd@google.com, Jann Horn , Paolo Bonzini , Cornelia Huck , Peter Xu , Alex Williamson , Daniel Vetter Subject: Re: [PATCH 3/3] mm: unexport follow_pfn Message-ID: Mail-Followup-To: Jason Gunthorpe , DRI Development , LKML , kvm@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-media@vger.kernel.org, 3pvd@google.com, Jann Horn , Paolo Bonzini , Cornelia Huck , Peter Xu , Alex Williamson , Daniel Vetter References: <20210316153303.3216674-1-daniel.vetter@ffwll.ch> <20210316153303.3216674-4-daniel.vetter@ffwll.ch> <20210324125211.GA2356281@nvidia.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Operating-System: Linux phenom 5.7.0-1-amd64 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210325_213400_624333_8B80BA97 X-CRM114-Status: GOOD ( 28.67 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Mar 24, 2021 at 08:17:10PM +0100, Daniel Vetter wrote: > On Wed, Mar 24, 2021 at 09:52:11AM -0300, Jason Gunthorpe wrote: > > On Tue, Mar 16, 2021 at 04:33:03PM +0100, Daniel Vetter wrote: > > > Both kvm (in bd2fae8da794 ("KVM: do not assume PTE is writable after > > > follow_pfn")) and vfio (in 07956b6269d3 ("vfio/type1: Use > > > follow_pte()")) have lost their callsites of follow_pfn(). All the > > > other ones have been switched over to unsafe_follow_pfn because they > > > cannot be fixed without breaking userspace api. > > > > > > Argueably the vfio code is still racy, but that's kinda a bigger > > > picture. But since it does leak the pte beyond where it drops the pt > > > lock, without anything else like an mmu notifier guaranteeing > > > coherence, the problem is at least clearly visible in the vfio code. > > > So good enough with me. > > > > > > I've decided to keep the explanation that after dropping the pt lock > > > you must have an mmu notifier if you keep using the pte somehow by > > > adjusting it and moving it into the kerneldoc for the new follow_pte() > > > function. > > > > > > Cc: 3pvd@google.com > > > Cc: Jann Horn > > > Cc: Paolo Bonzini > > > Cc: Jason Gunthorpe > > > Cc: Cornelia Huck > > > Cc: Peter Xu > > > Cc: Alex Williamson > > > Cc: linux-mm@kvack.org > > > Cc: linux-arm-kernel@lists.infradead.org > > > Cc: linux-samsung-soc@vger.kernel.org > > > Cc: linux-media@vger.kernel.org > > > Cc: kvm@vger.kernel.org > > > Signed-off-by: Daniel Vetter > > > --- > > > include/linux/mm.h | 2 -- > > > mm/memory.c | 26 +++++--------------------- > > > mm/nommu.c | 13 +------------ > > > 3 files changed, 6 insertions(+), 35 deletions(-) > > > > I think this is the right thing to do. > > Was just about to smash this into the topic branch for testing in > linux-next. Feel like an ack on the series, or at least the two mm > patches? Pushed them to my topic branch for a bit of testing in linux-next, hopefully goes all fine for a pull for 5.13. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel