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Thu, 15 Oct 2020 09:55:56 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id EGeGcatLBx4U for ; Thu, 15 Oct 2020 09:55:55 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by whitealder.osuosl.org (Postfix) with ESMTP id 17BC18850C for ; Thu, 15 Oct 2020 09:55:55 +0000 (UTC) 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 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-Language: en-GB Cc: linux-kernel@vger.kernel.org, jonathanh@nvidia.com, iommu@lists.linux-foundation.org, thierry.reding@gmail.com, linux-tegra@vger.kernel.org, digetx@gmail.com X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" 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); _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu