Messages in this thread | | | From | Lu Baolu <> | Subject | [PATCH v4 00/19] iommu: Retire detach_dev callback | Date | Wed, 4 Jan 2023 20:57:06 +0800 |
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Hi folks,
The iommu core calls the driver's detach_dev domain op callback only when a device is finished assigning to user space and iommu_group_release_dma_owner() is called to return the device to the kernel, where iommu core wants to set the default domain to the device but the driver didn't provide one. The code looks like:
/* * New drivers should support default domains and so the detach_dev() op * will never be called. Otherwise the NULL domain represents some * platform specific behavior. */ if (!new_domain) { if (WARN_ON(!group->domain->ops->detach_dev)) return -EINVAL; __iommu_group_for_each_dev(group, group->domain, iommu_group_do_detach_device); group->domain = NULL; return 0; }
In other words, if the iommu driver provides default domains, the .detach_dev callback will never be called; Otherwise, the .detach_dev callback is actually called to return control back to the platform DMA ops, other than detaching the domain from device.
This series cleanups this by:
- If the IOMMU driver provides default domains, remove .detach_dev callback. - Adds a new set_platform_dma iommu op. Any IOMMU driver that doesn't provide default domain should implement set_platform_dma callback instead. - Retire .detach_dev callback.
This series originates from various discussion in the community. Thank Jason, Robin and all others for their ideas. This series looks very long. It is necessary because I hope that change in each driver has a confirmation from its stakeholder. I will then be able to merge some of them to make the series cute.
The whole series is available on github: https://github.com/LuBaolu/intel-iommu/commits/iommu-retire-detach_dev-v4
Please review and suggest.
Change log: v4: - Drop the patch which renamed .attach_dev to .set_dev. As Robin said, "... I also wouldn't say that "attach" loses its meaning in a context where an equivalent "detach" operation is only ever implicit in reattaching to something else...". If we have a better name in the future, we can do it in other series. - Adjust the patch of "iommu: Add set_platform_dma_ops iommu ops" according to Jason's following suggestion " ... This is a bit ugly, it would be better to make the previous patch call set_platform_dma if it is set instead of detach_dev and then these patches should just rename the driver's fsl_pamu_detach_device to fsl_pamu_set_platform_dma ..." - Add a new patch to remove deferred attach check from __iommu_detach_domain() path. Make it a separate patch as the prerequisite to remove __iommu_detach_device() helper. - Rename set_platform_dma to set_platform_dma_ops to make it more meaningful.
v3: - https://lore.kernel.org/linux-iommu/20221128064648.1934720-1-baolu.lu@linux.intel.com/ - Setting blocking domain is not conceptually equal to detach_dev. Dropped all blocking domain related staffs in the previous version.
v2: - https://lore.kernel.org/linux-iommu/20220826123014.52709-1-baolu.lu@linux.intel.com/ - Replace .detach_dev callback with static block domain ops; - Rename .attach_dev to .set_dev.
v1: - https://lore.kernel.org/linux-iommu/20220516015759.2952771-1-baolu.lu@linux.intel.com/
Jason Gunthorpe (1): iommu: Remove deferred attach check from __iommu_detach_device()
Lu Baolu (18): iommu/amd: Remove detach_dev callback iommu/apple-dart: Remove detach_dev callback iommu/qcom: Remove detach_dev callback iommu/exynos: Remove detach_dev callback iommu/ipmmu: Remove detach_dev callback iommu/mtk: Remove detach_dev callback iommu/rockchip: Remove detach_dev callback iommu/sprd: Remove detach_dev callback iommu/sun50i: Remove detach_dev callback iommu: Add set_platform_dma_ops iommu ops iommu/fsl_pamu: Add set_platform_dma_ops callback iommu/msm: Add set_platform_dma_ops callback iommu/mtk_v1: Add set_platform_dma_ops callback iommu/omap: Add set_platform_dma_ops callback iommu/s390: Add set_platform_dma_ops callback iommu/gart: Add set_platform_dma_ops callback iommu/tegra: Add set_platform_dma_ops callback iommu: Remove detach_dev callback
include/linux/iommu.h | 8 +- include/trace/events/iommu.h | 7 -- drivers/iommu/amd/iommu.c | 26 ------- drivers/iommu/apple-dart.c | 24 ------ drivers/iommu/arm/arm-smmu/qcom_iommu.c | 23 ------ drivers/iommu/exynos-iommu.c | 1 - drivers/iommu/fsl_pamu_domain.c | 6 +- drivers/iommu/iommu-traces.c | 1 - drivers/iommu/iommu.c | 98 ++++++++++++------------- drivers/iommu/ipmmu-vmsa.c | 16 ---- drivers/iommu/msm_iommu.c | 6 +- drivers/iommu/mtk_iommu.c | 9 --- drivers/iommu/mtk_iommu_v1.c | 4 +- drivers/iommu/omap-iommu.c | 6 +- drivers/iommu/rockchip-iommu.c | 1 - drivers/iommu/s390-iommu.c | 7 +- drivers/iommu/sprd-iommu.c | 16 ---- drivers/iommu/sun50i-iommu.c | 1 - drivers/iommu/tegra-gart.c | 6 +- drivers/iommu/tegra-smmu.c | 5 +- 20 files changed, 73 insertions(+), 198 deletions(-)
-- 2.34.1
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