Re: [PATCH v6 00/12] iommu: Prepare to deliver page faults to user space

[Yan Zhao]

Tested and verified that IOPF requests and responses are triggered and
handled successfully with SVM enabled on DSA on SPR platform. 

Tested-by: Yan Zhao <yan.y.zhao@xxxxxxxxx>

On Thu, Sep 28, 2023 at 12:27:22PM +0800, Lu Baolu wrote:
> When a user-managed page table is attached to an IOMMU, it is necessary
> to deliver IO page faults to user space so that they can be handled
> appropriately. One use case for this is nested translation, which is
> currently being discussed in the mailing list.
> 
> I have posted a RFC series [1] that describes the implementation of
> delivering page faults to user space through IOMMUFD. This series has
> received several comments on the IOMMU refactoring, which I am trying to
> address in this series.
> 
> The major refactoring includes:
> 
> - [PATCH 01 ~ 04] Move include/uapi/linux/iommu.h to
>   include/linux/iommu.h. Remove the unrecoverable fault data definition.
> - [PATCH 05 ~ 06] Remove iommu_[un]register_device_fault_handler().
> - [PATCH 07 ~ 10] Separate SVA and IOPF. Make IOPF a generic page fault
>   handling framework.
> - [PATCH 11 ~ 12] Improve iopf framework for iommufd use.
> 
> This is also available at github [2].
> 
> [1] https://lore.kernel.org/linux-iommu/20230530053724.232765-1-baolu.lu@xxxxxxxxxxxxxxx/
> [2] https://github.com/LuBaolu/intel-iommu/commits/preparatory-io-pgfault-delivery-v6
> 
> Change log:
> v6:
>  - [PATCH 09/12] Check IS_ERR() against the iommu domain. [Jingqi/Jason]
>  - [PATCH 12/12] Rename the comments and name of iopf_queue_flush_dev(),
>    no functionality changes. [Kevin]
>  - All patches rebased on the latest iommu/core branch.
> 
> v5: https://lore.kernel.org/linux-iommu/20230914085638.17307-1-baolu.lu@xxxxxxxxxxxxxxx/
>  - Consolidate per-device fault data management. (New patch 11)
>  - Improve iopf_queue_flush_dev(). (New patch 12)
> 
> v4: https://lore.kernel.org/linux-iommu/20230825023026.132919-1-baolu.lu@xxxxxxxxxxxxxxx/
>  - Merge iommu_fault_event and iopf_fault. They are duplicate.
>  - Move iommu_report_device_fault() and iommu_page_response() to
>    io-pgfault.c.
>  - Move iommu_sva_domain_alloc() to iommu-sva.c.
>  - Add group->domain and use it directly in sva fault handler.
>  - Misc code refactoring and refining.
> 
> v3: https://lore.kernel.org/linux-iommu/20230817234047.195194-1-baolu.lu@xxxxxxxxxxxxxxx/
>  - Convert the fault data structures from uAPI to kAPI.
>  - Merge iopf_device_param into iommu_fault_param.
>  - Add debugging on domain lifetime for iopf.
>  - Remove patch "iommu: Change the return value of dev_iommu_get()".
>  - Remove patch "iommu: Add helper to set iopf handler for domain".
>  - Misc code refactoring and refining.
> 
> v2: https://lore.kernel.org/linux-iommu/20230727054837.147050-1-baolu.lu@xxxxxxxxxxxxxxx/
>  - Remove unrecoverable fault data definition as suggested by Kevin.
>  - Drop the per-device fault cookie code considering that doesn't make
>    much sense for SVA.
>  - Make the IOMMU page fault handling framework generic. So that it can
>    available for use cases other than SVA.
> 
> v1: https://lore.kernel.org/linux-iommu/20230711010642.19707-1-baolu.lu@xxxxxxxxxxxxxxx/
> 
> Lu Baolu (12):
>   iommu: Move iommu fault data to linux/iommu.h
>   iommu/arm-smmu-v3: Remove unrecoverable faults reporting
>   iommu: Remove unrecoverable fault data
>   iommu: Cleanup iopf data structure definitions
>   iommu: Merge iopf_device_param into iommu_fault_param
>   iommu: Remove iommu_[un]register_device_fault_handler()
>   iommu: Merge iommu_fault_event and iopf_fault
>   iommu: Prepare for separating SVA and IOPF
>   iommu: Make iommu_queue_iopf() more generic
>   iommu: Separate SVA and IOPF
>   iommu: Consolidate per-device fault data management
>   iommu: Improve iopf_queue_flush_dev()
> 
>  include/linux/iommu.h                         | 258 ++++++++---
>  drivers/iommu/intel/iommu.h                   |   2 +-
>  drivers/iommu/iommu-sva.h                     |  71 ---
>  include/uapi/linux/iommu.h                    | 161 -------
>  .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c   |  14 +-
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   |  51 +-
>  drivers/iommu/intel/iommu.c                   |  25 +-
>  drivers/iommu/intel/svm.c                     |   8 +-
>  drivers/iommu/io-pgfault.c                    | 438 +++++++++++-------
>  drivers/iommu/iommu-sva.c                     |  82 +++-
>  drivers/iommu/iommu.c                         | 232 ----------
>  MAINTAINERS                                   |   1 -
>  drivers/iommu/Kconfig                         |   4 +
>  drivers/iommu/Makefile                        |   3 +-
>  drivers/iommu/intel/Kconfig                   |   1 +
>  15 files changed, 578 insertions(+), 773 deletions(-)
>  delete mode 100644 drivers/iommu/iommu-sva.h
>  delete mode 100644 include/uapi/linux/iommu.h
> 
> -- 
> 2.34.1
>