OVERVIEW
--------
AMD IOMMU Hardware Accelerated Virtualized IOMMU (HW-vIOMMU) feature
provides partial hardware acceleration for implementing guest IOMMUs.
When the feature is enabled, the following components are virtualized:
* Guest Command Buffer
* Guest Event Log (work-in-progress)
* Guest PPR Log (work-in-progress))
In addition, this feature can be used in combination with nested IOMMU page
tables to accelerated address translation from GIOVA to GPA. In this case,
the host page table (a.k.a stage2 or v1) is managed by the hypervisor
(i.e. KVM/VFIO) and the guest page table (a.k.a stage1 or v2) is managed
by the guest IOMMU driver (e.g. when booting guest kernel with
amd_iommu=pgtable_v2 mode).
Since the IOMMU hardware virtualizes the guest command buffer, this allows
IOMMU operations to be accelerated such as invalidation of guest pages
(i.e. stage1) when the command is issued by the guest kernel without
intervention from the hypervisor.
This series is implemented on top of the IOMMUFD framework. It leverages
the exisiting APIs and ioctls for providing guest iommu information
(i.e. struct iommu_hw_info_amd), and allowing guest to provide guest page
table information (i.e. struct iommu_hwpt_amd_v2) for setting up user
domain.
Please see the [4],[5], and [6] for more detail on the AMD HW-vIOMMU.
NOTES
-----
This series is organized into two parts:
* Part1: Preparing IOMMU driver for HW-vIOMMU support (Patch 1-8).
* Part2: Introducing HW-vIOMMU support (Patch 9-21).
* Patch 12 and 21 extends the existing IOMMUFD ioctls to support
additional opterations, which can be categorized into:
- Ioctls to init/destroy AMD HW-vIOMMU instance
- Ioctls to attach/detach guest devices to the AMD HW-vIOMMU instance.
- Ioctls to attach/detach guest domains to the AMD HW-vIOMMU instance.
- Ioctls to trap certain AMD HW-vIOMMU MMIO register accesses.
- Ioctls to trap AMD HW-vIOMMU command buffer initialization.
Since these are specific to AMD HW-vIOMMU implementation but still
want to leverage /dev/iommu, they are separated from existing VFIO-related
ioctls.
* Initial revision only supports 1 pasid in the guest (i.e. pasid 0).
Multiple pasids support will be added in subsequent revision.
GITHUB
------
* Working Linux kernel prototype of this series [1] is based on [3].
* This sereis is tested with QEMU [2] (work-in-progress)
REFERENCES
----------
[1] Linux Github branch for this series
https://github.com/AMDESE/linux/tree/wip/iommufd_nesting-06192023-yi_amd_viommu_20230621
[2] QEMU Github branch to be used for testing this series.
https://github.com/AMDESE/qemu/tree/wip/iommufd_rfcv4.mig.reset.v4_var3%2Bnesting_amd_viommu_202300621
[3] Base Github branch from Yi Lui.
https://github.com/yiliu1765/iommufd/tree/wip/iommufd_nesting-06192023-yi
[4] AMD IOMMU Specification
https://www.amd.com/system/files/TechDocs/48882_3.07_PUB.pdf
[5] KVM Forum 2020 Presentation
https://tinyurl.com/2p8b543c
[6] KVM Forum 2021 Presentation
https://tinyurl.com/49sy42ry
Thank you,
Suravee Suthikulpanit
Suravee Suthikulpanit (21):
iommu/amd: Declare helper functions as extern
iommu/amd: Clean up spacing in amd_iommu_ops declaration
iommu/amd: Update PASID, GATS, and GLX feature related macros
iommu/amd: Modify domain_enable_v2() to add giov parameter
iommu/amd: Refactor set_dte_entry() helper function
iommu/amd: Modify set_dte_entry() to add gcr3 input parameter
iommu/amd: Modify set_dte_entry() to add user domain input parameter
iommu/amd: Allow nested IOMMU page tables
iommu/amd: Add support for hw_info for iommu capability query
iommu/amd: Introduce vIOMMU-specific events and event info
iommu/amd: Introduce Reset vMMIO Command
iommu/amd: Introduce AMD vIOMMU-specific UAPI
iommu/amd: Introduce vIOMMU command-line option
iommu/amd: Initialize vIOMMU private address space regions
iommu/amd: Introduce vIOMMU vminit and vmdestroy ioctl
iommu/amd: Introduce vIOMMU ioctl for updating device mapping table
iommu/amd: Introduce vIOMMU ioctl for updating domain mapping
iommu/amd: Introduce vIOMMU ioctl for handling guest MMIO accesses
iommu/amd: Introduce vIOMMU ioctl for handling command buffer mapping
iommu/amd: Introduce vIOMMU ioctl for setting up guest CR3
iommufd: Introduce AMD HW-vIOMMU IOCTL
drivers/iommu/amd/Makefile | 2 +-
drivers/iommu/amd/amd_iommu.h | 40 +-
drivers/iommu/amd/amd_iommu_types.h | 62 +-
drivers/iommu/amd/amd_viommu.h | 57 ++
drivers/iommu/amd/init.c | 29 +-
drivers/iommu/amd/io_pgtable.c | 18 +-
drivers/iommu/amd/iommu.c | 370 +++++++--
drivers/iommu/amd/iommu_v2.c | 2 +-
drivers/iommu/amd/viommu.c | 1110 +++++++++++++++++++++++++++
drivers/iommu/iommufd/Makefile | 3 +-
drivers/iommu/iommufd/amd_viommu.c | 158 ++++
drivers/iommu/iommufd/main.c | 17 +-
include/linux/amd-viommu.h | 26 +
include/linux/iommu.h | 1 +
include/linux/iommufd.h | 8 +
include/uapi/linux/amd_viommu.h | 145 ++++
include/uapi/linux/iommufd.h | 31 +
17 files changed, 1964 insertions(+), 115 deletions(-)
create mode 100644 drivers/iommu/amd/amd_viommu.h
create mode 100644 drivers/iommu/amd/viommu.c
create mode 100644 drivers/iommu/iommufd/amd_viommu.c
create mode 100644 include/linux/amd-viommu.h
create mode 100644 include/uapi/linux/amd_viommu.h
--
2.34.1
