Messages in this thread | | | From | Lu Baolu <> | Subject | [PATCH v4 0/6] iommu: Extend changing default domain to normal group | Date | Wed, 22 Mar 2023 14:49:50 +0800 |
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The IOMMU group sysfs interface allows users to change the default domain of a group. The current implementation uses device_lock() to make sure that the devices in the group are not bound to any driver and won't be bound during the process of changing the default domain. In order to avoid a possible deadlock caused by lock order of device_lock and group->mutex, it limits the functionality to singleton groups only.
The recently implemented DMA ownership framework can be applied here to replace device_lock(). In addition, use group->mutex to ensure that the iommu ops of the device are always valid during the process of changing default domain.
With above replacement and enhancement, the device_lock() could be removed and the singleton-group-only limitation could be removed.
This series is based on v6.3-rc3, and I also have it on github: https://github.com/LuBaolu/intel-iommu/commits/iommu-sysfs-default-domain-extension-v4
Change log: v4: - Whole series reviewed by Jason. - Robin suggested further simplification of using arm_iommu_release_mapping() directly. https://lore.kernel.org/linux-iommu/7b248ba1-3967-5cd8-82e9-0268c706d320@arm.com/ - Rebase the whole series to v6.3-rc3.
v3: - https://lore.kernel.org/linux-iommu/20230306025804.13912-1-baolu.lu@linux.intel.com/ - "arm_iommu_detach_device() is a noop" is not entirely right. It is used to make the iommu driver stop using the domain that it is about to free. It cannot be a NOP or it is a UAF. [Jason] - Use Jason's new arm_iommu_release_device() proposal instead.
v2: - https://lore.kernel.org/linux-iommu/20230217094736.159005-1-baolu.lu@linux.intel.com/ - Use group->mutex instead of an additional rw lock.
v1: initial post - https://lore.kernel.org/linux-iommu/20230213074941.919324-1-baolu.lu@linux.intel.com/
Lu Baolu (6): iommu/ipmmu-vmsa: Call arm_iommu_release_mapping() in release path iommu: Split iommu_group_remove_device() into helpers iommu: Same critical region for device release and removal iommu: Move lock from iommu_change_dev_def_domain() to its caller iommu: Replace device_lock() with group->mutex iommu: Cleanup iommu_change_dev_def_domain()
drivers/iommu/iommu.c | 273 ++++++++---------- drivers/iommu/ipmmu-vmsa.c | 14 +- .../ABI/testing/sysfs-kernel-iommu_groups | 1 - 3 files changed, 130 insertions(+), 158 deletions(-)
-- 2.34.1
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