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,DKIM_INVALID, DKIM_SIGNED,MAILING_LIST_MULTI,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 93410C07E99 for ; Mon, 5 Jul 2021 19:04:33 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 E948961982 for ; Mon, 5 Jul 2021 19:04:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E948961982 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4GJZqg2mWsz3bYN for ; Tue, 6 Jul 2021 05:04:31 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=GRwf1cGa; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=will@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=GRwf1cGa; dkim-atps=neutral Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4GJZqB70MRz2yx2 for ; Tue, 6 Jul 2021 05:04:06 +1000 (AEST) Received: by mail.kernel.org (Postfix) with ESMTPSA id 3D07161978; Mon, 5 Jul 2021 19:03:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625511844; bh=o012umLuvyjggdb73nB1nx1kOYsPv1SNeUIs18hDcAw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=GRwf1cGaUQnGNSK48BMiS8/L53RP5G/QW+0L7WarqJg3vdXhPi76IMHEfxJBcIPa3 O/IVWGS61Gw63qZ6P/lu+E1G7lOjBRQgMMYZUlxciRBcXpXeaEm0Nt8VlI20vyORW0 5Yt77iWQoVMzfxA0eNrndYooJS41ndFVzjZWCxmusBkktvSuT3rDjxcvXFg+FyE3zq Tiys8WKwLxyKU0wwkmXs/VX0V/xsNc/cZvd76dhCDw80UkiEfPmHKQyUCziEG4n9+X zngjj2Bp6GquWJbjoHo8XOCLo60dYdheBX5hvWTEA+kb21c5xQf9Khdj2j/E3DZMQq mzeeqFIjv4raA== Date: Mon, 5 Jul 2021 20:03:52 +0100 From: Will Deacon To: Nathan Chancellor Subject: Re: [PATCH v15 06/12] swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing Message-ID: <20210705190352.GA19461@willie-the-truck> References: <20210624155526.2775863-7-tientzu@chromium.org> <20210630114348.GA8383@willie-the-truck> <20210701074045.GA9436@willie-the-truck> <20210702135856.GB11132@willie-the-truck> <0f7bd903-e309-94a0-21d7-f0e8e9546018@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: heikki.krogerus@linux.intel.com, thomas.hellstrom@linux.intel.com, peterz@infradead.org, joonas.lahtinen@linux.intel.com, dri-devel@lists.freedesktop.org, chris@chris-wilson.co.uk, grant.likely@arm.com, paulus@samba.org, Frank Rowand , mingo@kernel.org, Marek Szyprowski , Stefano Stabellini , Saravana Kannan , xypron.glpk@gmx.de, Joerg Roedel , "Rafael J . Wysocki" , Christoph Hellwig , Bartosz Golaszewski , bskeggs@redhat.com, linux-pci@vger.kernel.org, xen-devel@lists.xenproject.org, Thierry Reding , intel-gfx@lists.freedesktop.org, matthew.auld@intel.com, linux-devicetree , Jianxiong Gao , Daniel Vetter , Konrad Rzeszutek Wilk , maarten.lankhorst@linux.intel.com, airlied@linux.ie, Dan Williams , linuxppc-dev@lists.ozlabs.org, jani.nikula@linux.intel.com, Rob Herring , rodrigo.vivi@intel.com, Bjorn Helgaas , Claire Chang , boris.ostrovsky@oracle.com, Andy Shevchenko , jgross@suse.com, Nicolas Boichat , Greg KH , Randy Dunlap , Qian Cai , lkml , Tomasz Figa , "list@263.net:IOMMU DRIVERS" , Jim Quinlan , Tom Lendacky , Robin Murphy , bauerman@linux.ibm.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Hi Nathan, I may have just spotted something in these logs... On Fri, Jul 02, 2021 at 10:55:17PM -0700, Nathan Chancellor wrote: > [ 2.340956] pci 0000:0c:00.1: Adding to iommu group 4 > [ 2.340996] pci 0000:0c:00.2: Adding to iommu group 4 > [ 2.341038] pci 0000:0c:00.3: Adding to iommu group 4 > [ 2.341078] pci 0000:0c:00.4: Adding to iommu group 4 > [ 2.341122] pci 0000:0c:00.6: Adding to iommu group 4 > [ 2.341163] pci 0000:0d:00.0: Adding to iommu group 4 > [ 2.341203] pci 0000:0d:00.1: Adding to iommu group 4 > [ 2.361821] pci 0000:00:00.2: AMD-Vi: Found IOMMU cap 0x40 > [ 2.361839] pci 0000:00:00.2: AMD-Vi: Extended features (0x206d73ef22254ade): > [ 2.361846] PPR X2APIC NX GT IA GA PC GA_vAPIC > [ 2.361861] AMD-Vi: Interrupt remapping enabled > [ 2.361865] AMD-Vi: Virtual APIC enabled > [ 2.361870] AMD-Vi: X2APIC enabled > [ 2.362272] AMD-Vi: Lazy IO/TLB flushing enabled So at this point, the AMD IOMMU driver does: swiotlb = (iommu_default_passthrough() || sme_me_mask) ? 1 : 0; where 'swiotlb' is a global variable indicating whether or not swiotlb is in use. It's picked up a bit later on by pci_swiotlb_late_init(), which will call swiotlb_exit() if 'swiotlb' is false. Now, that used to work fine, because swiotlb_exit() clears 'io_tlb_default_mem' to NULL, but now with the restricted DMA changes, I think that all the devices which have successfully probed beforehand will have stale pointers to the freed structure in their 'dev->dma_io_tlb_mem' field. Will