[PATCH v6 00/13] iommu/amd: Introduce Nested Translation support

Suravee Suthikulpanit
2026-01-15T06:08:41Z

This series introduces support for AMD IOMMU nested page table translation
with the host (v1) and guest (v2) page tables.

In this mode, the AMD IOMMU driver configures the Device Table Entry (DTE)
with host page table root pointer, which is configured by allocating domain
with page table type IOMMU_HWPT_ALLOC_NEST_PARENT.

The guest page tables and Guest CR3 (GCR3) tables are managed by Guest OS,
and stored in the guest DTE (gDTE) in guest memory. VMM is responsible for
passing gDTE information to the host IOMMU driver using struct
iommu_hwpt_amd_guest when allocating a domain type IOMMU_DOMAIN_NESTED.
Then, the gDTE is parsed and program onto host DTE by the AMD IOMMU driver.

In addition, this series introduces base code for IOMMUFD vIOMMU for AMD
IOMMU, and implements vIOMMU-based nested domain allocation interface.
The struct nested_domain to store nested domain information, and
set_dte_nested() helper function to handle DTE programing for the nested
domain.

The series is separated into two parts:
* Patch 1 adds support for hw_info for AMD IOMMU
* Patch 2-4 are preparatory patches.
* Patch 5-13 implement nested translation support

Please note that this is a preparatory series for nested translation w/
AMD vIOMMU support. Currently, the amd_iommu_alloc_domain_nested() has not
been hooked with the struct iommufd_viommu_ops.alloc_domain_nested.
This will be fully enabled in subsequent series, which will introduce
the support for IOMMUFD vIOMMU for AMD.

Changes from V5:
(https://lore.kernel.org/linux-iommu/20251112182506.7165-1-suravee.suthikulpanit@amd.com/)
* This series is rebased on top of
Git repo: git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux.git
Branch: next
Commit: c7fe9384c85d ("amd/iommu: Make protection domain ID functions non-static")

* Rebase on top of Linux v6.19-rc1, and adopt the new gen_pt framework.

* Remove patch "iommu/amd: Make amd_iommu_pdom_id_alloc() non-static"
since it has been accepted from another series.

* Remove patch "iommu/amd: Make amd_iommu_pdom_id_free() non-static"
since it has been accepted from another series.

* Patch 1:
- Rebase "[PATCH v5] iommu/amd: Add support for hw_info for iommu capability query"
(https://lore.kernel.org/linux-iommu/20250926141901.511313-1-suravee.suthikulpanit@amd.com/)

* Patch 10:
- Fix race condition using xa_lock()/xa_unlock() per Nicolin comment
- Introduce gdom_info_load_or_alloc_locked() per Jason suggestion

* Patch 12:
- Rework logic for set_dte_v1() / amd_iommu_set_dte_v1()
- Remove check for snp enabled and domid=0 since no longer applicable.

* Patch 13:
- Move amd_iommu_update_dte() to nested_attach_device().
- Add WARN_ON for PASID enabled.

Thanks,
Suravee

Suravee Suthikulpanit (13):
iommu/amd: Add support for hw_info for iommu capability query
iommu/amd: Rename DEV_DOMID_MASK to DTE_DOMID_MASK
iommu/amd: Make amd_iommu_make_clear_dte() non-static inline
iommu/amd: Introduce helper function amd_iommu_update_dte()
iommufd: Introduce data struct for AMD nested domain allocation
iommu/amd: Always enable GCR3TRPMode when supported.
iommu/amd: Add support for nest parent domain allocation
iommu/amd: Introduce struct amd_iommu_viommu
iommu/amd: Add support for nested domain allocation
iommu/amd: Introduce gDomID-to-hDomID Mapping and handle parent domain
invalidation
iommu/amd: Refactor persistent DTE bits programming into
amd_iommu_make_clear_dte()
iommu/amd: Refactor logic to program the host page table in DTE
iommu/amd: Add support for nested domain attach/detach

drivers/iommu/amd/Kconfig | 10 +
drivers/iommu/amd/Makefile | 1 +
drivers/iommu/amd/amd_iommu.h | 33 ++++
drivers/iommu/amd/amd_iommu_types.h | 48 ++++-
drivers/iommu/amd/init.c | 10 +-
drivers/iommu/amd/iommu.c | 264 +++++++++++++++----------
drivers/iommu/amd/iommufd.c | 78 ++++++++
drivers/iommu/amd/iommufd.h | 20 ++
drivers/iommu/amd/nested.c | 294 ++++++++++++++++++++++++++++
include/uapi/linux/iommufd.h | 39 ++++
10 files changed, 692 insertions(+), 105 deletions(-)
create mode 100644 drivers/iommu/amd/iommufd.c
create mode 100644 drivers/iommu/amd/iommufd.h
create mode 100644 drivers/iommu/amd/nested.c

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2.34.1