This is the basic functionality for iommufd to support iommufd_device_replace() and IOMMU_HWPT_ALLOC for physical devices.
iommufd_device_replace() allows changing the HWPT associated with the device to a new IOAS or HWPT. Replace does this in way that failure leaves things unchanged, and utilizes the iommu iommu_group_replace_domain() API to allow the iommu driver to perform an optional non-disruptive change.
IOMMU_HWPT_ALLOC allows HWPTs to be explicitly allocated by the user and used by attach or replace. At this point it isn't very useful since the HWPT is the same as the automatically managed HWPT from the IOAS. However a following series will allow userspace to customize the created HWPT.
The implementation is complicated because we have to introduce some per-iommu_group memory in iommufd and redo how we think about multi-device groups to be more explicit. This solves all the locking problems in the prior attempts.
This series is infrastructure work for the following series which: - Add replace for attach - Expose replace through VFIO APIs - Implement driver parameters for HWPT creation (nesting)
Once review of this is complete I will keep it on a side branch and accumulate the following series when they are ready so we can have a stable base and make more incremental progress. When we have all the parts together to get a full implementation it can go to Linus.
I have this on github:
https://github.com/jgunthorpe/linux/commits/iommufd_hwpt
Jason Gunthorpe (12): iommufd: Move isolated msi enforcement to iommufd_device_bind() iommufd: Add iommufd_group iommufd: Replace the hwpt->devices list with iommufd_group iommufd: Use the iommufd_group to avoid duplicate reserved groups and msi setup iommufd: Make sw_msi_start a group global iommufd: Move putting a hwpt to a helper function iommufd: Add enforced_cache_coherency to iommufd_hw_pagetable_alloc() iommufd: Add iommufd_device_replace() iommufd: Make destroy_rwsem use a lock class per object type iommufd: Add IOMMU_HWPT_ALLOC iommufd/selftest: Return the real idev id from selftest mock_domain iommufd/selftest: Add a selftest for IOMMU_HWPT_ALLOC
Nicolin Chen (2): iommu: Introduce a new iommu_group_replace_domain() API iommufd/selftest: Test iommufd_device_replace()
drivers/iommu/iommu-priv.h | 10 + drivers/iommu/iommu.c | 30 ++ drivers/iommu/iommufd/device.c | 482 +++++++++++++----- drivers/iommu/iommufd/hw_pagetable.c | 96 +++- drivers/iommu/iommufd/io_pagetable.c | 5 +- drivers/iommu/iommufd/iommufd_private.h | 44 +- drivers/iommu/iommufd/iommufd_test.h | 7 + drivers/iommu/iommufd/main.c | 17 +- drivers/iommu/iommufd/selftest.c | 40 ++ include/linux/iommufd.h | 1 + include/uapi/linux/iommufd.h | 26 + tools/testing/selftests/iommu/iommufd.c | 64 ++- .../selftests/iommu/iommufd_fail_nth.c | 57 ++- tools/testing/selftests/iommu/iommufd_utils.h | 59 ++- 14 files changed, 758 insertions(+), 180 deletions(-) create mode 100644 drivers/iommu/iommu-priv.h
base-commit: ac395958f9156733246b5bc3a481c6d38c321a7a