[PATCH v2 0/6] iommu/amd: Add Generic IO Page Table Framework Support for v2 Page Table

[Vasant Hegde <vasant.hegde@amd.com>]

This series introduces a new usage model for the v2 page table, where it
can be used to implement support for DMA-API by adopting the generic
IO page table framework.

One of the target usecases is to support nested IO page tables
where the guest uses the guest IO page table (v2) for translating
GVA to GPA, and the hypervisor uses the host I/O page table (v1) for
translating GPA to SPA. This is a pre-requisite for supporting the new
HW-assisted vIOMMU presented at the KVM Forum 2020.

  https://static.sched.com/hosted_files/kvmforum2020/26/vIOMMU%20KVM%20Forum%202020.pdf

The following components are introduced in this series:

- Part 1 (patch 1-3 and 5)
  Refactor the current IOMMU page table code to adopt the generic IO page
  table framework, and add AMD IOMMU Guest (v2) page table management code.

- Part 2 (patch 4)
  Add support for the AMD IOMMU Guest IO Protection feature (GIOV)
  where requests from the I/O device without a PASID are treated as
  if they have PASID of 0.

- Part 3 (patch 6)
  Introduce new "amd_iommu_pgtable" command-line to allow users
  to select the mode of operation (v1 or v2).

See AMD I/O Virtualization Technology Specification for more detail.

  http://www.amd.com/system/files/TechDocs/48882_IOMMU_3.05_PUB.pdf

@Robin,
   We are not addressing your comment on cleaning up pgsize_bitmap in
   this series. As mentioned in other thread [1] we can work on that
   as separate cleanup series.

   [1] https://lore.kernel.org/linux-iommu/15337b9f-48d7-d956-5d6c-b40319ba38ad@amd.com/


Thanks,
Vasant

Changes from v1 -> v2 :
  - Allow v2 page table only when FEATURE_GT is enabled
  - V2 page table doesn't support IOMMU passthrough mode. Hence added
    check to fall back to v1 mode if system is booted with iommu=pt
  - Overloaded amd_iommu command line option (removed amd_iommu_pgtable option)
  - Override supported page sizes dynamically instead of selecting at boot time.

V1 patchset : https://lore.kernel.org/linux-iommu/20220603112107.8603-1-vasant.hegde@amd.com/T/#t

Changes from RFC -> v1:
  - Addressed review comments from Joerg
  - Reimplemented v2 page table

RFC patchset : https://lore.kernel.org/linux-iommu/20210312090411.6030-1-suravee.suthikulpanit@amd.com/T/#t

Suravee Suthikulpanit (4):
  iommu/amd: Refactor amd_iommu_domain_enable_v2 to remove locking
  iommu/amd: Update sanity check when enable PRI/ATS for IOMMU v1 table
  iommu/amd: Add support for Guest IO protection
  iommu/amd: Add support for using AMD IOMMU v2 page table for DMA-API

Vasant Hegde (2):
  iommu/amd: Initial support for AMD IOMMU v2 page table
  iommu/amd: Add command-line option to enable different page table

 .../admin-guide/kernel-parameters.txt         |   2 +
 drivers/iommu/amd/Makefile                    |   2 +-
 drivers/iommu/amd/amd_iommu_types.h           |   8 +-
 drivers/iommu/amd/init.c                      |  36 +-
 drivers/iommu/amd/io_pgtable_v2.c             | 407 ++++++++++++++++++
 drivers/iommu/amd/iommu.c                     |  89 +++-
 drivers/iommu/io-pgtable.c                    |   1 +
 include/linux/io-pgtable.h                    |   2 +
 8 files changed, 518 insertions(+), 29 deletions(-)
 create mode 100644 drivers/iommu/amd/io_pgtable_v2.c

-- 
2.31.1