[PATCH v3 00/16] cover-letter: iommufd: Add vIOMMU infrastructure (Part-2: vDEVICE)

[Nicolin Chen]

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 vID 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-v3
Paring QEMU branch for testing:
https://github.com/nicolinc/qemu/commits/wip/for_iommufd_viommu_p2-v3

Changelog
v3
 * 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 (3):
  iommu: Add iommu_copy_struct_from_full_user_array helper
  iommu/arm-smmu-v3: Allow ATS for IOMMU_DOMAIN_NESTED
  iommu/arm-smmu-v3: Update comments about ATS and bypass

Nicolin Chen (13):
  iommufd/viommu: Introduce IOMMUFD_OBJ_VDEVICE and its related struct
  iommufd/viommu: Add a default_viommu_ops for IOMMU_VIOMMU_TYPE_DEFAULT
  iommufd/viommu: Add IOMMU_VDEVICE_ALLOC ioctl
  iommufd/selftest: Add IOMMU_VDEVICE_ALLOC test coverage
  iommu/viommu: Add cache_invalidate for IOMMU_VIOMMU_TYPE_DEFAULT
  iommufd/hw_pagetable: Allow viommu->ops->cache_invalidate for
    hwpt_nested
  iommufd: Allow hwpt_id to carry viommu_id for IOMMU_HWPT_INVALIDATE
  iommufd/viommu: Add vdev_to_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
  iommu/arm-smmu-v3: Add arm_vsmmu_cache_invalidate

 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |   9 +-
 drivers/iommu/iommufd/iommufd_private.h       |  12 ++
 drivers/iommu/iommufd/iommufd_test.h          |  30 +++
 include/linux/iommu.h                         |  53 ++++-
 include/linux/iommufd.h                       |  50 +++++
 include/uapi/linux/iommufd.h                  |  61 +++++-
 tools/testing/selftests/iommu/iommufd_utils.h |  83 +++++++
 .../arm/arm-smmu-v3/arm-smmu-v3-iommufd.c     | 162 +++++++++++++-
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   |  50 +++--
 drivers/iommu/iommufd/hw_pagetable.c          |  45 +++-
 drivers/iommu/iommufd/main.c                  |   6 +
 drivers/iommu/iommufd/selftest.c              | 122 ++++++++++-
 drivers/iommu/iommufd/viommu.c                |  93 +++++++-
 drivers/iommu/iommufd/viommu_api.c            |  21 ++
 tools/testing/selftests/iommu/iommufd.c       | 204 +++++++++++++++++-
 Documentation/userspace-api/iommufd.rst       |  58 +++--
 16 files changed, 1007 insertions(+), 52 deletions(-)

-- 
2.43.0