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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 22A0EC433E1 for ; Fri, 21 Aug 2020 18:33:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 05B9B20720 for ; Fri, 21 Aug 2020 18:33:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726701AbgHUSdg convert rfc822-to-8bit (ORCPT ); Fri, 21 Aug 2020 14:33:36 -0400 Received: from mail.fireflyinternet.com ([77.68.26.236]:54387 "EHLO fireflyinternet.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726666AbgHUSdc (ORCPT ); Fri, 21 Aug 2020 14:33:32 -0400 X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from localhost (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP (TLS) id 22202502-1500050 for multiple; Fri, 21 Aug 2020 19:33:12 +0100 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT In-Reply-To: <20190525054136.27810-8-baolu.lu@linux.intel.com> References: <20190525054136.27810-1-baolu.lu@linux.intel.com> <20190525054136.27810-8-baolu.lu@linux.intel.com> Subject: Re: [PATCH v4 07/15] iommu/vt-d: Delegate the dma domain to upper layer From: Chris Wilson Cc: ashok.raj@intel.com, jacob.jun.pan@intel.com, kevin.tian@intel.com, jamessewart@arista.com, tmurphy@arista.com, dima@arista.com, sai.praneeth.prakhya@intel.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Lu Baolu To: David Woodhouse , Joerg Roedel , Lu Baolu Date: Fri, 21 Aug 2020 19:33:10 +0100 Message-ID: <159803479017.29194.1359332295829225843@build.alporthouse.com> User-Agent: alot/0.9 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Quoting Lu Baolu (2019-05-25 06:41:28) > This allows the iommu generic layer to allocate a dma domain and > attach it to a device through the iommu api's. With all types of > domains being delegated to upper layer, we can remove an internal > flag which was used to distinguish domains mananged internally or > externally. I'm seeing some really strange behaviour with this patch on a 32b Skylake system (and still present on mainline). Before this patch everything is peaceful and appears to work correctly. Applying this patch, and we fail to initialise the GPU with a few DMAR errors reported, e.g. [ 20.279445] DMAR: DRHD: handling fault status reg 3 [ 20.279508] DMAR: [DMA Read] Request device [00:02.0] fault addr 8900a000 [fault reason 05] PTE Write access is not set Setting an identity map for the igfx made the DMAR errors disappear, but the GPU still failed to initialise. There's no difference in the DMAR configuration dmesg between working and the upset patch. And the really strange part is that switching to a 64b kernel with this patch, it's working. Any suggestions on what I should look for? -Chris