From: Robin Murphy <robin.murphy@arm.com>
To: "Tian, Kevin" <kevin.tian@intel.com>,
"joro@8bytes.org" <joro@8bytes.org>
Cc: "will@kernel.org" <will@kernel.org>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"baolu.lu@linux.intel.com" <baolu.lu@linux.intel.com>,
"suravee.suthikulpanit@amd.com" <suravee.suthikulpanit@amd.com>,
"vasant.hegde@amd.com" <vasant.hegde@amd.com>,
"mjrosato@linux.ibm.com" <mjrosato@linux.ibm.com>,
"gerald.schaefer@linux.ibm.com" <gerald.schaefer@linux.ibm.com>,
"schnelle@linux.ibm.com" <schnelle@linux.ibm.com>,
"linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 03/15] iommu: Always register bus notifiers
Date: Thu, 7 Jul 2022 10:58:56 +0100 [thread overview]
Message-ID: <f3a7143c-5e89-817a-a33d-7353d51a987d@arm.com> (raw)
In-Reply-To: <BN9PR11MB5276B6689D88D3D5D57915908C839@BN9PR11MB5276.namprd11.prod.outlook.com>
On 2022-07-07 07:31, Tian, Kevin wrote:
>> From: Robin Murphy <robin.murphy@arm.com>
>> Sent: Wednesday, July 6, 2022 1:08 AM
>>
>> The number of bus types that the IOMMU subsystem deals with is small and
>> manageable, so pull that list into core code as a first step towards
>> cleaning up all the boilerplate bus-awareness from drivers. Calling
>> iommu_probe_device() before bus->iommu_ops is set will simply return
>> -ENODEV and not break the notifier call chain, so there should be no
>> harm in proactively registering all our bus notifiers at init time.
>>
>
> Suppose we miss a check on iommu ops in iommu_release_device():
>
> if (!dev->iommu) <<<<<<<
> return;
>
> iommu_device_unlink(dev->iommu->iommu_dev, dev);
>
> ops = dev_iommu_ops(dev);
> ops->release_device(dev);
>
> following the rationale in patch01 a device could be removed when
> it's associated with a known but not registered instance.
No, because at that point the instance is only known internally to the
driver. As long as it isn't erroneously returned from
->probe_device(dev), dev->iommu will remain NULL and the rest of the
core code works as expected.
Thanks,
Robin.
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next prev parent reply other threads:[~2022-07-07 10:00 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-05 17:08 [PATCH v3 00/15] iommu: Retire bus_set_iommu() Robin Murphy
2022-07-05 17:08 ` [PATCH v3 01/15] iommu/vt-d: Handle race between registration and device probe Robin Murphy
2022-07-06 1:39 ` Baolu Lu
2022-07-07 6:51 ` Tian, Kevin
2022-07-08 7:52 ` Baolu Lu
2022-07-15 12:37 ` Robin Murphy
2022-07-19 0:06 ` Lu Baolu
2022-07-05 17:08 ` [PATCH v3 02/15] iommu/amd: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 03/15] iommu: Always register bus notifiers Robin Murphy
2022-07-06 1:53 ` Baolu Lu
2022-07-06 13:43 ` Robin Murphy
2022-07-07 0:20 ` Baolu Lu
2022-07-07 6:34 ` Tian, Kevin
2022-07-07 9:38 ` Robin Murphy
2022-07-07 6:31 ` Tian, Kevin
2022-07-07 9:58 ` Robin Murphy [this message]
2022-07-08 5:50 ` Tian, Kevin
2022-07-05 17:08 ` [PATCH v3 04/15] iommu: Move bus setup to IOMMU device registration Robin Murphy
2022-07-06 2:35 ` Baolu Lu
2022-07-06 14:37 ` Robin Murphy
2022-07-07 1:19 ` Baolu Lu
2022-07-07 6:51 ` Tian, Kevin
2022-07-07 10:58 ` Robin Murphy
2022-07-08 5:52 ` Tian, Kevin
2022-07-05 17:08 ` [PATCH v3 05/15] iommu/amd: Clean up bus_set_iommu() Robin Murphy
2022-07-05 17:08 ` [PATCH v3 06/15] iommu/arm-smmu: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 07/15] iommu/arm-smmu-v3: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 08/15] iommu/dart: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 09/15] iommu/exynos: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 10/15] iommu/ipmmu-vmsa: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 11/15] iommu/mtk: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 12/15] iommu/omap: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 13/15] iommu/tegra-smmu: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 14/15] iommu/virtio: " Robin Murphy
2022-07-05 17:08 ` [PATCH v3 15/15] iommu: " Robin Murphy
2022-07-07 7:45 ` Tian, Kevin
2022-07-07 12:49 ` Matthew Rosato
2022-07-07 12:54 ` Matthew Rosato
2022-07-07 14:58 ` Robin Murphy
2022-07-07 16:42 ` Matthew Rosato
2022-07-08 8:14 ` [PATCH] iommu/s390: fail probe for non-pci device Niklas Schnelle
2022-07-08 8:17 ` [PATCH v3 00/15] iommu: Retire bus_set_iommu() Niklas Schnelle
2022-07-15 13:12 ` Robin Murphy
2022-07-21 7:17 ` Tian, Kevin
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