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[v7,00/10] iommufd: Add vIOMMU infrastructure (Part-2: vDEVICE)

Message ID cover.1730836308.git.nicolinc@nvidia.com (mailing list archive)
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Series iommufd: Add vIOMMU infrastructure (Part-2: vDEVICE) | expand

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Nicolin Chen Nov. 5, 2024, 8:05 p.m. UTC 
Following the previous vIOMMU series, this adds another vDEVICE structure,
representing the association from an iommufd_device to an iommufd_viommu.
This gives the whole architecture a new "v" layer:
  _______________________________________________________________________
 |                      iommufd (with vIOMMU/vDEVICE)                    |
 |                        _____________      _____________               |
 |                       |             |    |             |              |
 |      |----------------|    vIOMMU   |<---|   vDEVICE   |<------|      |
 |      |                |             |    |_____________|       |      |
 |      |     ______     |             |     _____________     ___|____  |
 |      |    |      |    |             |    |             |   |        | |
 |      |    | IOAS |<---|(HWPT_PAGING)|<---| HWPT_NESTED |<--| DEVICE | |
 |      |    |______|    |_____________|    |_____________|   |________| |
 |______|________|______________|__________________|_______________|_____|
        |        |              |                  |               |
  ______v_____   |        ______v_____       ______v_____       ___v__
 |   struct   |  |  PFN  |  (paging)  |     |  (nested)  |     |struct|
 |iommu_device|  |------>|iommu_domain|<----|iommu_domain|<----|device|
 |____________|   storage|____________|     |____________|     |______|

This vDEVICE object is used to collect and store all vIOMMU-related device
information/attributes in a VM. As an initial series for vDEVICE, add only
the virt_id to the vDEVICE, which is a vIOMMU specific device ID in a VM:
e.g. vSID of ARM SMMUv3, vDeviceID of AMD IOMMU, and vRID of Intel VT-d to
a Context Table. This virt_id helps IOMMU drivers to link the vID to a pID
of the device against the physical IOMMU instance. This is essential for a
vIOMMU-based invalidation, where the request contains a device's vID for a
device cache flush, e.g. ATC invalidation.

Therefore, with this vDEVICE object, support a vIOMMU-based invalidation,
by reusing IOMMUFD_CMD_HWPT_INVALIDATE for a vIOMMU object to flush cache
with a given driver data.

As for the implementation of the series, add driver support in ARM SMMUv3
for a real world use case.

This series is on Github:
https://github.com/nicolinc/iommufd/commits/iommufd_viommu_p2-v7
(QEMU branch for testing will be provided in Jason's nesting series)

Changelog
v7
 * Added "Reviewed-by" from Jason
 * Corrected a line of comments in iommufd_vdevice_destroy()
v6
 https://lore.kernel.org/all/cover.1730313494.git.nicolinc@nvidia.com/
 * Fixed kdoc in the uAPI header
 * Fixed indentations in iommufd.rst
 * Replaced vdev->idev with vdev->dev
 * Added "Reviewed-by" from Kevin and Jason
 * Updated kdoc of struct iommu_vdevice_alloc
 * Fixed lockdep function call in iommufd_viommu_find_dev
 * Added missing iommu_dev validation between viommu and idev
 * Skipped SMMUv3 driver changes (to post in a separate series)
 * Replaced !cache_invalidate_user in WARN_ON of the allocation path
   with cache_invalidate_user validation in iommufd_hwpt_invalidate
v5
 https://lore.kernel.org/all/cover.1729897278.git.nicolinc@nvidia.com/
 * Dropped driver-allocated vDEVICE support
 * Changed vdev_to_dev helper to iommufd_viommu_find_dev
v4
 https://lore.kernel.org/all/cover.1729555967.git.nicolinc@nvidia.com/
 * Added missing brackets in switch-case
 * Fixed the unreleased idev refcount issue
 * Reworked the iommufd_vdevice_alloc allocator
 * Dropped support for IOMMU_VIOMMU_TYPE_DEFAULT
 * Added missing TEST_LENGTH and fail_nth coverages
 * Added a verification to the driver-allocated vDEVICE object
 * Added an iommufd_vdevice_abort for a missing mutex protection
 * Added a u64 structure arm_vsmmu_invalidation_cmd for user command
   conversion
v3
 https://lore.kernel.org/all/cover.1728491532.git.nicolinc@nvidia.com/
 * Added Jason's Reviewed-by
 * Split this invalidation part out of the part-1 series
 * Repurposed VDEV_ID ioctl to a wider vDEVICE structure and ioctl
 * Reduced viommu_api functions by allowing drivers to access viommu
   and vdevice structure directly
 * Dropped vdevs_rwsem by using xa_lock instead
 * Dropped arm_smmu_cache_invalidate_user
v2
 https://lore.kernel.org/all/cover.1724776335.git.nicolinc@nvidia.com/
 * Limited vdev_id to one per idev
 * Added a rw_sem to protect the vdev_id list
 * Reworked driver-level APIs with proper lockings
 * Added a new viommu_api file for IOMMUFD_DRIVER config
 * Dropped useless iommu_dev point from the viommu structure
 * Added missing index numnbers to new types in the uAPI header
 * Dropped IOMMU_VIOMMU_INVALIDATE uAPI; Instead, reuse the HWPT one
 * Reworked mock_viommu_cache_invalidate() using the new iommu helper
 * Reordered details of set/unset_vdev_id handlers for proper lockings
v1
 https://lore.kernel.org/all/cover.1723061377.git.nicolinc@nvidia.com/

Thanks!
Nicolin

Jason Gunthorpe (1):
  iommu: Add iommu_copy_struct_from_full_user_array helper

Nicolin Chen (9):
  iommufd/viommu: Add IOMMUFD_OBJ_VDEVICE and IOMMU_VDEVICE_ALLOC ioctl
  iommufd/selftest: Add IOMMU_VDEVICE_ALLOC test coverage
  iommu/viommu: Add cache_invalidate to iommufd_viommu_ops
  iommufd: Allow hwpt_id to carry viommu_id for IOMMU_HWPT_INVALIDATE
  iommufd/viommu: Add iommufd_viommu_find_dev helper
  iommufd/selftest: Add mock_viommu_cache_invalidate
  iommufd/selftest: Add IOMMU_TEST_OP_DEV_CHECK_CACHE test command
  iommufd/selftest: Add vIOMMU coverage for IOMMU_HWPT_INVALIDATE ioctl
  Documentation: userspace-api: iommufd: Update vDEVICE

 drivers/iommu/iommufd/iommufd_private.h       |  18 ++
 drivers/iommu/iommufd/iommufd_test.h          |  30 +++
 include/linux/iommu.h                         |  48 ++++-
 include/linux/iommufd.h                       |  22 ++
 include/uapi/linux/iommufd.h                  |  31 ++-
 tools/testing/selftests/iommu/iommufd_utils.h |  83 +++++++
 drivers/iommu/iommufd/driver.c                |  13 ++
 drivers/iommu/iommufd/hw_pagetable.c          |  40 +++-
 drivers/iommu/iommufd/main.c                  |   6 +
 drivers/iommu/iommufd/selftest.c              |  98 ++++++++-
 drivers/iommu/iommufd/viommu.c                |  76 +++++++
 tools/testing/selftests/iommu/iommufd.c       | 204 +++++++++++++++++-
 .../selftests/iommu/iommufd_fail_nth.c        |   4 +
 Documentation/userspace-api/iommufd.rst       |  41 +++-
 14 files changed, 688 insertions(+), 26 deletions(-)


base-commit: 0780dd4af09a5360392f5c376c35ffc2599a9c0e