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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 E4F2EC43381 for ; Fri, 15 Mar 2019 03:18:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BBF4421873 for ; Fri, 15 Mar 2019 03:18:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727143AbfCODSu (ORCPT ); Thu, 14 Mar 2019 23:18:50 -0400 Received: from mga09.intel.com ([134.134.136.24]:15673 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726571AbfCODSu (ORCPT ); Thu, 14 Mar 2019 23:18:50 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 14 Mar 2019 20:18:49 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,480,1544515200"; d="scan'208";a="127118324" Received: from allen-box.sh.intel.com (HELO [10.239.159.136]) ([10.239.159.136]) by orsmga006.jf.intel.com with ESMTP; 14 Mar 2019 20:18:47 -0700 Cc: baolu.lu@linux.intel.com, Tom Murphy , Dmitry Safonov , Jacob Pan , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 0/7] iommu/vt-d: Fix-up device-domain relationship by refactoring to use iommu group default domain. To: James Sewart , iommu@lists.linux-foundation.org References: <0F0C82BE-86E5-4BAC-938C-6F7629E18D27@arista.com> <83B82113-8AE5-4B0C-A079-F389520525BD@arista.com> From: Lu Baolu Message-ID: <0e74cc54-bb90-a620-5763-466cb11aaef7@linux.intel.com> Date: Fri, 15 Mar 2019 11:13:22 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <83B82113-8AE5-4B0C-A079-F389520525BD@arista.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi James, On 3/14/19 7:56 PM, James Sewart wrote: > Patches 1 and 2 are the same as v1. > > v1-v2: > Refactored ISA direct mappings to be returned by iommu_get_resv_regions. > Integrated patch by Lu to defer turning on DMAR until iommu.c has mapped > reserved regions. > Integrated patches by Lu to remove more unused code in cleanup. > > Lu: I didn't integrate your patch to set the default domain type as it > isn't directly related to the aim of this patchset. Instead patch 4 Without those patches, user experience will be affected and some devices will not work on Intel platforms anymore. For a long time, Intel IOMMU driver has its own logic to determine whether a device requires an identity domain. For example, when user specifies "iommu=pt" in kernel parameter, all device will be attached with the identity domain. Further more, some quirky devices require an identity domain to be used before enabling DMA remapping, otherwise, it will not work. This was done by adding quirk bits in Intel IOMMU driver. So from my point of view, one way is porting all those quirks and kernel parameters into IOMMU generic layer, or opening a door for vendor IOMMU driver to determine the default domain type by their own. I prefer the latter option since it will not impact any behaviors on other architectures. > addresses the issue of a device requiring an identity domain by ignoring > the domain param in attach_device and printing a warning. This will not work as I commented in that thread. > > I booted some of our devices with this patchset and haven't seen any > issues. It doesn't look like we have any devices with RMRR's though so > those codepaths aren't tested. > > James Sewart (7): > iommu: Move iommu_group_create_direct_mappings to after device_attach > iommu/vt-d: Implement apply_resv_region for reserving IOVA ranges > iommu/vt-d: Expose ISA direct mapping region via > iommu_get_resv_regions > iommu/vt-d: Ignore domain parameter in attach_device if device > requires identity map > iommu/vt-d: Allow IOMMU_DOMAIN_DMA to be allocated by iommu_ops > iommu/vt-d: Remove lazy allocation of domains > > Lu Baolu (1): > iommu/vt-d: Enable DMA remapping after rmrr mapped > > drivers/iommu/intel-iommu.c | 444 +++++++++++------------------------- > drivers/iommu/iommu.c | 4 +- > 2 files changed, 131 insertions(+), 317 deletions(-) > Best regards, Lu Baolu