[PATCH 00/20] iommu: Refactoring domain allocation interface

Lu Baolu
2024-05-29T05:36:09Z

The IOMMU subsystem has undergone some changes, including the removal
of iommu_ops from the bus structure. Consequently, the existing domain
allocation interface, which relies on a bus type argument, is no longer
relevant:

struct iommu_domain *iommu_domain_alloc(struct bus_type *bus)

This series is designed to refactor the use of this interface. It
proposes two new interfaces to replace iommu_domain_alloc():

- iommu_user_domain_alloc(): This interface is intended for allocating
iommu domains managed by userspace for device passthrough scenarios,
such as those used by iommufd, vfio, and vdpa. It clearly indicates
that the domain is for user-managed device DMA.

If an IOMMU driver does not implement iommu_ops->domain_alloc_user,
this interface will rollback to the generic paging domain allocation.

- iommu_paging_domain_alloc(): This interface is for allocating iommu
domains managed by kernel drivers for kernel DMA purposes. It takes a
device pointer as a parameter, which better reflects the current
design of the IOMMU subsystem.

The majority of device drivers currently using iommu_domain_alloc() do
so to allocate a domain for a specific device and then attach that
domain to the device. These cases can be straightforwardly migrated to
the new interfaces.

However, there are some drivers with more complex use cases that do
not fit neatly into this new scheme. For example:

$ git grep "= iommu_domain_alloc"
arch/arm/mm/dma-mapping.c: mapping->domain = iommu_domain_alloc(bus);
drivers/gpu/drm/rockchip/rockchip_drm_drv.c: private->domain = iommu_domain_alloc(private->iommu_dev->bus);
drivers/gpu/drm/tegra/drm.c: tegra->domain = iommu_domain_alloc(&platform_bus_type);
drivers/infiniband/hw/usnic/usnic_uiom.c: pd->domain = domain = iommu_domain_alloc(dev->bus);

This series leave those cases unchanged and keep iommu_domain_alloc()
for their usage. But new drivers should not use it anymore.

The whole series is also available on GitHub:
https://github.com/LuBaolu/intel-iommu/commits/iommu-domain-allocation-refactor-v1

Lu Baolu (20):
iommu: Add iommu_user_domain_alloc() interface
iommufd: Use iommu_user_domain_alloc()
vfio/type1: Use iommu_paging_domain_alloc()
vhost-vdpa: Use iommu_user_domain_alloc()
iommu: Add iommu_paging_domain_alloc() interface
drm/msm: Use iommu_paging_domain_alloc()
drm/nouveau/tegra: Use iommu_paging_domain_alloc()
gpu: host1x: Use iommu_paging_domain_alloc()
media: nvidia: tegra: Use iommu_paging_domain_alloc()
media: venus: firmware: Use iommu_paging_domain_alloc()
ath10k: Use iommu_paging_domain_alloc()
wifi: ath11k: Use iommu_paging_domain_alloc()
remoteproc: Use iommu_paging_domain_alloc()
soc/fsl/qbman: Use iommu_paging_domain_alloc()
iommu/vt-d: Add helper to allocate paging domain
iommu/vt-d: Add domain_alloc_paging support
iommu/vt-d: Simplify compatibility check for identity domain
iommu/vt-d: Enhance compatibility check for paging domain attach
iommu/vt-d: Remove domain_update_iommu_cap()
iommu/vt-d: Remove domain_update_iommu_superpage()

include/linux/iommu.h | 12 +
drivers/gpu/drm/msm/msm_iommu.c | 8 +-
.../drm/nouveau/nvkm/engine/device/tegra.c | 4 +-
drivers/gpu/host1x/dev.c | 6 +-
drivers/iommu/intel/iommu.c | 319 ++++++++----------
drivers/iommu/intel/pasid.c | 28 +-
drivers/iommu/iommu.c | 62 ++++
drivers/iommu/iommufd/hw_pagetable.c | 20 +-
.../media/platform/nvidia/tegra-vde/iommu.c | 6 +-
drivers/media/platform/qcom/venus/firmware.c | 6 +-
drivers/net/wireless/ath/ath10k/snoc.c | 6 +-
drivers/net/wireless/ath/ath11k/ahb.c | 6 +-
drivers/remoteproc/remoteproc_core.c | 6 +-
drivers/soc/fsl/qbman/qman_portal.c | 4 +-
drivers/vfio/vfio_iommu_type1.c | 7 +-
drivers/vhost/vdpa.c | 11 +-
16 files changed, 253 insertions(+), 258 deletions(-)

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2.34.1