Re: [PATCH v4 10/17] iommufd: Support IOMMU_HWPT_ALLOC allocation with user data

[Jason Gunthorpe]

On Thu, Sep 21, 2023 at 12:51:31AM -0700, Yi Liu wrote:
> IOMMU_HWPT_ALLOC already supports iommu_domain allocation for usersapce.
> But it can only allocate a hw_pagetable that associates to a given IOAS,
> i.e. only a kernel-managed hw_pagetable of IOMMU_HWPT_TYPE_DEFAULT type.
> 
> IOMMU drivers can now support user-managed hw_pagetables, for two-stage
> translation use cases, that require user data input from the user space.
> 
> Extend the IOMMU_HWPT_ALLOC ioctl to accept non-default hwpt_type with a
> type specified user data. Also, update the @pt_id to accept hwpt_id too
> besides an ioas_id. Then, pass them to the downstream alloc_fn().
> 
> Co-developed-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
> Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
> Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
> ---
>  drivers/iommu/iommufd/hw_pagetable.c | 19 ++++++++++++++++++-
>  include/uapi/linux/iommufd.h         | 23 +++++++++++++++++++++--
>  2 files changed, 39 insertions(+), 3 deletions(-)

Can we also come with a small vt-d patch that does implement an op for
this? Or is it too big?

It would be nice if we could wrap IOMMU_HWPT_ALLOC into one
self-contained series and another series for invalidate.

Jason