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=-12.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 741DEC433E7 for ; Thu, 15 Oct 2020 09:55:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0F02F206D4 for ; Thu, 15 Oct 2020 09:55:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731095AbgJOJz5 (ORCPT ); Thu, 15 Oct 2020 05:55:57 -0400 Received: from foss.arm.com ([217.140.110.172]:53614 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727165AbgJOJzz (ORCPT ); Thu, 15 Oct 2020 05:55:55 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5ED2FD6E; Thu, 15 Oct 2020 02:55:54 -0700 (PDT) Received: from [10.57.48.76] (unknown [10.57.48.76]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 01A7C3F66B; Thu, 15 Oct 2020 02:55:52 -0700 (PDT) Subject: Re: [PATCH v7 3/3] iommu/tegra-smmu: Add PCI support To: Nicolin Chen Cc: thierry.reding@gmail.com, joro@8bytes.org, digetx@gmail.com, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, jonathanh@nvidia.com References: <20201009161936.23122-1-nicoleotsuka@gmail.com> <20201009161936.23122-4-nicoleotsuka@gmail.com> <20201015041346.GA13936@Asurada-Nvidia> From: Robin Murphy Message-ID: <340afbc0-5513-0742-d2d2-1ab908248af3@arm.com> Date: Thu, 15 Oct 2020 10:55:52 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Thunderbird/78.3.2 MIME-Version: 1.0 In-Reply-To: <20201015041346.GA13936@Asurada-Nvidia> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org On 2020-10-15 05:13, Nicolin Chen wrote: > On Wed, Oct 14, 2020 at 06:42:36PM +0100, Robin Murphy wrote: >> On 2020-10-09 17:19, Nicolin Chen wrote: >>> This patch simply adds support for PCI devices. >>> >>> Reviewed-by: Dmitry Osipenko >>> Tested-by: Dmitry Osipenko >>> Signed-off-by: Nicolin Chen >>> --- >>> >>> Changelog >>> v6->v7 >>> * Renamed goto labels, suggested by Thierry. >>> v5->v6 >>> * Added Dmitry's Reviewed-by and Tested-by. >>> v4->v5 >>> * Added Dmitry's Reviewed-by >>> v3->v4 >>> * Dropped !iommu_present() check >>> * Added CONFIG_PCI check in the exit path >>> v2->v3 >>> * Replaced ternary conditional operator with if-else in .device_group() >>> * Dropped change in tegra_smmu_remove() >>> v1->v2 >>> * Added error-out labels in tegra_smmu_probe() >>> * Dropped pci_request_acs() since IOMMU core would call it. >>> >>> drivers/iommu/tegra-smmu.c | 35 +++++++++++++++++++++++++---------- >>> 1 file changed, 25 insertions(+), 10 deletions(-) >>> >>> diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c >>> index be29f5977145..2941d6459076 100644 >>> --- a/drivers/iommu/tegra-smmu.c >>> +++ b/drivers/iommu/tegra-smmu.c >>> @@ -10,6 +10,7 @@ >>> #include >>> #include >>> #include >>> +#include >>> #include >>> #include >>> #include >>> @@ -865,7 +866,11 @@ static struct iommu_group *tegra_smmu_device_group(struct device *dev) >>> group->smmu = smmu; >>> group->soc = soc; >>> - group->group = iommu_group_alloc(); >>> + if (dev_is_pci(dev)) >>> + group->group = pci_device_group(dev); >> >> Just to check, is it OK to have two or more swgroups "owning" the same >> iommu_group if an existing one gets returned here? It looks like that might >> not play nice with the use of iommu_group_set_iommudata(). > > Do you mean by "gets returned here" the "IS_ERR" check below? I mean that unlike iommu_group_alloc()/generic_device_group(), pci_device_group() may give you back a group that already contains another device and has already been set up from that device's perspective. This can happen for topological reasons like requester ID aliasing through a PCI-PCIe bridge or lack of isolation between functions. Robin. >>> + else >>> + group->group = generic_device_group(dev); >>> + >>> if (IS_ERR(group->group)) { >>> devm_kfree(smmu->dev, group); >>> mutex_unlock(&smmu->lock);