Re: [PATCH v8 0/7] IOMMU user API enhancement

2020-09-08 Thread Jacob Pan
Hi Joerg, Alex, and all.

Just wondering if there are any more comments? We have discussed this
at LPC, there are other patches depending on this set.

Thanks,

Jacob

On Mon, 31 Aug 2020 11:24:53 -0700
Jacob Pan  wrote:

> IOMMU user API header was introduced to support nested DMA
> translation and related fault handling. The current UAPI data
> structures consist of three areas that cover the interactions between
> host kernel and guest:
>  - fault handling
>  - cache invalidation
>  - bind guest page tables, i.e. guest PASID
> 
> Future extensions are likely to support more architectures and vIOMMU
> features.
> 
> In the previous discussion, using user-filled data size and feature
> flags is made a preferred approach over a unified version number.
> https://lkml.org/lkml/2020/1/29/45
> 
> In addition to introduce argsz field to data structures, this
> patchset is also trying to document the UAPI design, usage, and
> extension rules. VT-d driver changes to utilize the new argsz field
> is included, VFIO usage is to follow.
> 
> This set is available at:
> https://github.com/jacobpan/linux.git vsva_v5.8_uapi_v8
> 
> Thanks,
> 
> Jacob
> 
> 
> Changelog:
> v8
>   - Rebased to v5.9-rc2
>   - Addressed review comments from Eric Auger
> 1. added a check for the unused vendor flags
> 2. commit message improvements
> v7
>   - Added PASID data format enum for range checking
>   - Tidy up based on reviews from Alex W.
>   - Removed doc section for vIOMMU fault handling
> v6
>   - Renamed all UAPI functions with iommu_uapi_ prefix
>   - Replaced argsz maxsz checking with flag specific size checks
>   - Documentation improvements based on suggestions by Eric
> Auger Replaced example code with a pointer to the actual code
>   - Added more checks for illegal flags combinations
>   - Added doc file to MAINTAINERS
> v5
>   - Addjusted paddings in UAPI data to be 8 byte aligned
>   - Do not clobber argsz in IOMMU core before passing on to
> vendor driver
>   - Removed pr_warn_ for invalid UAPI data check, just return
> -EINVAL
>   - Clarified VFIO responsibility in UAPI data handling
>   - Use iommu_uapi prefix to differentiate APIs has in-kernel
> caller
>   - Added comment for unchecked flags of invalidation
> granularity
>   - Added example in doc to show vendor data checking
> 
> v4
>   - Added checks of UAPI data for reserved fields, version, and
> flags.
>   - Removed version check from vendor driver (vt-d)
>   - Relaxed argsz check to match the UAPI struct size instead
> of variable union size
>   - Updated documentation
> 
> v3:
>   - Rewrote backward compatibility rule to support existing code
> re-compiled with newer kernel UAPI header that runs on older
> kernel. Based on review comment from Alex W.
> https://lore.kernel.org/linux-iommu/20200611094741.6d118...@w520.home/
>   - Take user pointer directly in UAPI functions. Perform argsz
> check and copy_from_user() in IOMMU driver. Eliminate the need for
> VFIO or other upper layer to parse IOMMU data.
>   - Create wrapper function for in-kernel users of UAPI
> functions v2:
>   - Removed unified API version and helper
>   - Introduced argsz for each UAPI data
>   - Introduced UAPI doc
> 
> 
> Jacob Pan (7):
>   docs: IOMMU user API
>   iommu/uapi: Add argsz for user filled data
>   iommu/uapi: Introduce enum type for PASID data format
>   iommu/uapi: Use named union for user data
>   iommu/uapi: Rename uapi functions
>   iommu/uapi: Handle data and argsz filled by users
>   iommu/vt-d: Check UAPI data processed by IOMMU core
> 
>  Documentation/userspace-api/iommu.rst | 211
> ++
> MAINTAINERS   |   1 +
> drivers/iommu/intel/iommu.c   |  25 ++--
> drivers/iommu/intel/svm.c |  13 ++-
> drivers/iommu/iommu.c | 205
> +++--
> include/linux/iommu.h |  35 --
> include/uapi/linux/iommu.h|  25 ++-- 7 files changed, 470
> insertions(+), 45 deletions(-) create mode 100644
> Documentation/userspace-api/iommu.rst
> 

[Jacob Pan]
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[PATCH v8 0/7] IOMMU user API enhancement

2020-08-31 Thread Jacob Pan
IOMMU user API header was introduced to support nested DMA translation and
related fault handling. The current UAPI data structures consist of three
areas that cover the interactions between host kernel and guest:
 - fault handling
 - cache invalidation
 - bind guest page tables, i.e. guest PASID

Future extensions are likely to support more architectures and vIOMMU features.

In the previous discussion, using user-filled data size and feature flags is
made a preferred approach over a unified version number.
https://lkml.org/lkml/2020/1/29/45

In addition to introduce argsz field to data structures, this patchset is also
trying to document the UAPI design, usage, and extension rules. VT-d driver
changes to utilize the new argsz field is included, VFIO usage is to follow.

This set is available at:
https://github.com/jacobpan/linux.git vsva_v5.8_uapi_v8

Thanks,

Jacob


Changelog:
v8
- Rebased to v5.9-rc2
- Addressed review comments from Eric Auger
  1. added a check for the unused vendor flags
  2. commit message improvements
v7
- Added PASID data format enum for range checking
- Tidy up based on reviews from Alex W.
- Removed doc section for vIOMMU fault handling
v6
- Renamed all UAPI functions with iommu_uapi_ prefix
- Replaced argsz maxsz checking with flag specific size checks
- Documentation improvements based on suggestions by Eric Auger
  Replaced example code with a pointer to the actual code
- Added more checks for illegal flags combinations
- Added doc file to MAINTAINERS
v5
- Addjusted paddings in UAPI data to be 8 byte aligned
- Do not clobber argsz in IOMMU core before passing on to vendor driver
- Removed pr_warn_ for invalid UAPI data check, just return -EINVAL
- Clarified VFIO responsibility in UAPI data handling
- Use iommu_uapi prefix to differentiate APIs has in-kernel caller
- Added comment for unchecked flags of invalidation granularity
- Added example in doc to show vendor data checking

v4
- Added checks of UAPI data for reserved fields, version, and flags.
- Removed version check from vendor driver (vt-d)
- Relaxed argsz check to match the UAPI struct size instead of variable
  union size
- Updated documentation

v3:
- Rewrote backward compatibility rule to support existing code
  re-compiled with newer kernel UAPI header that runs on older
  kernel. Based on review comment from Alex W.
  https://lore.kernel.org/linux-iommu/20200611094741.6d118...@w520.home/
- Take user pointer directly in UAPI functions. Perform argsz check
  and copy_from_user() in IOMMU driver. Eliminate the need for
  VFIO or other upper layer to parse IOMMU data.
- Create wrapper function for in-kernel users of UAPI functions
v2:
- Removed unified API version and helper
- Introduced argsz for each UAPI data
- Introduced UAPI doc


Jacob Pan (7):
  docs: IOMMU user API
  iommu/uapi: Add argsz for user filled data
  iommu/uapi: Introduce enum type for PASID data format
  iommu/uapi: Use named union for user data
  iommu/uapi: Rename uapi functions
  iommu/uapi: Handle data and argsz filled by users
  iommu/vt-d: Check UAPI data processed by IOMMU core

 Documentation/userspace-api/iommu.rst | 211 ++
 MAINTAINERS   |   1 +
 drivers/iommu/intel/iommu.c   |  25 ++--
 drivers/iommu/intel/svm.c |  13 ++-
 drivers/iommu/iommu.c | 205 +++--
 include/linux/iommu.h |  35 --
 include/uapi/linux/iommu.h|  25 ++--
 7 files changed, 470 insertions(+), 45 deletions(-)
 create mode 100644 Documentation/userspace-api/iommu.rst

-- 
2.7.4

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