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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 99606C2D0E4 for ; Mon, 23 Nov 2020 13:55:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4F72F20729 for ; Mon, 23 Nov 2020 13:55:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388815AbgKWNy5 (ORCPT ); Mon, 23 Nov 2020 08:54:57 -0500 Received: from mga12.intel.com ([192.55.52.136]:47964 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733086AbgKWNy4 (ORCPT ); Mon, 23 Nov 2020 08:54:56 -0500 IronPort-SDR: P5u1POPLGhOGC7LP3R1NL81LikzlBTvHKqs3M2ghLBPLl1FHszmNEjjKcKeBjGqmXGg4C4WkoB Skqlxs+nCLrA== X-IronPort-AV: E=McAfee;i="6000,8403,9813"; a="151027269" X-IronPort-AV: E=Sophos;i="5.78,363,1599548400"; d="scan'208";a="151027269" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Nov 2020 05:54:54 -0800 IronPort-SDR: ujcBQ6RvfszZYenJ8xid3jLrnvKfurOLfhNZE08oJqQlaw5VQnzKnrOUCgYi+g8M8VkawmKZFb jB9SXcg5o/dw== X-IronPort-AV: E=Sophos;i="5.78,363,1599548400"; d="scan'208";a="546420754" Received: from blu2-mobl3.ccr.corp.intel.com (HELO [10.254.210.240]) ([10.254.210.240]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Nov 2020 05:54:51 -0800 Cc: baolu.lu@linux.intel.com, Joerg Roedel , Ashok Raj , Christoph Hellwig , Sohil Mehta , Robin Murphy , Jacob Pan , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Shameerali Kolothum Thodi Subject: Re: [PATCH v9 1/4] iommu: Move def_domain type check for untrusted device into core To: Will Deacon References: <20201121135620.3496419-1-baolu.lu@linux.intel.com> <20201121135620.3496419-2-baolu.lu@linux.intel.com> <20201123120449.GB10233@willie-the-truck> <5f6f0d5e-0cfc-2274-b186-180f50b8b1df@linux.intel.com> <20201123130335.GD10233@willie-the-truck> From: Lu Baolu Message-ID: Date: Mon, 23 Nov 2020 21:54:49 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <20201123130335.GD10233@willie-the-truck> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Will, On 2020/11/23 21:03, Will Deacon wrote: > Hi Baolu, > > On Mon, Nov 23, 2020 at 08:55:17PM +0800, Lu Baolu wrote: >> On 2020/11/23 20:04, Will Deacon wrote: >>> On Sat, Nov 21, 2020 at 09:56:17PM +0800, Lu Baolu wrote: >>>> @@ -1645,13 +1655,10 @@ struct __group_domain_type { >>>> static int probe_get_default_domain_type(struct device *dev, void *data) >>>> { >>>> - const struct iommu_ops *ops = dev->bus->iommu_ops; >>>> struct __group_domain_type *gtype = data; >>>> unsigned int type = 0; >>>> - if (ops->def_domain_type) >>>> - type = ops->def_domain_type(dev); >>>> - >>>> + type = iommu_get_mandatory_def_domain_type(dev); >>> >>> afaict, this code is only called from probe_alloc_default_domain(), which >>> has: >>> >>> /* Ask for default domain requirements of all devices in the group */ >>> __iommu_group_for_each_dev(group, >ype, >>> probe_get_default_domain_type); >>> >>> if (!gtype.type) >>> gtype.type = iommu_def_domain_type; >>> >>> so is there actually a need to introduce the new >>> iommu_get_mandatory_def_domain_type() function, given that a type of 0 >>> always ends up resolving to the default domain type? >> >> Another consumer of this helper is in the next patch: >> >> + dev_def_dom = iommu_get_mandatory_def_domain_type(dev); >> + >> + /* Check if user requested domain is supported by the device or not */ >> + if (!type) { >> + /* >> + * If the user hasn't requested any specific type of domain and >> + * if the device supports both the domains, then default to the >> + * domain the device was booted with >> + */ >> + type = iommu_get_def_domain_type(dev); >> + } else if (dev_def_dom && type != dev_def_dom) { >> + dev_err_ratelimited(prev_dev, "Device cannot be in %s domain\n", >> + iommu_domain_type_str(type)); >> + ret = -EINVAL; >> + goto out; >> + } >> >> I also added the untrusted device check in >> iommu_get_mandatory_def_domain_type(), so that we don't need to care >> about this in multiple places. > > I see, but isn't this also setting the default domain type in the case that > it gets back a type of 0? I think it would be nice to avoid having both > iommu_get_mandatory_def_domain_type() and iommu_get_def_domain_type() of we > can, as it's really not clear which one to use when and what is meant by > "mandatory" imo. Yes, agreed. I will remove iommu_get_mandatory_def_domain_type() and keep iommu_get_def_domain_type() as the only helper in the next version. Best regards, baolu