Re: [PATCH v2 0/6] IOMMUFD: Deliver IO page faults to user space

[Baolu Lu]

On 2024/1/13 5:56, Joel Granados wrote:
> On Thu, Oct 26, 2023 at 10:49:24AM +0800, Lu Baolu wrote:
> > Hi folks,
> >
> > This series implements the functionality of delivering IO page faults to
> > user space through the IOMMUFD framework for nested translation. Nested
> > translation is a hardware feature that supports two-stage translation
> > tables for IOMMU. The second-stage translation table is managed by the
> > host VMM, while the first-stage translation table is owned by user
> > space. This allows user space to control the IOMMU mappings for its
> > devices.
> >
> > When an IO page fault occurs on the first-stage translation table, the
> > IOMMU hardware can deliver the page fault to user space through the
> > IOMMUFD framework. User space can then handle the page fault and respond
> > to the device top-down through the IOMMUFD. This allows user space to
> > implement its own IO page fault handling policies.
> >
> > User space indicates its capability of handling IO page faults by
> > setting the IOMMU_HWPT_ALLOC_IOPF_CAPABLE flag when allocating a
> > hardware page table (HWPT). IOMMUFD will then set up its infrastructure
> > for page fault delivery. On a successful return of HWPT allocation, the
> > user can retrieve and respond to page faults by reading and writing to
> > the file descriptor (FD) returned in out_fault_fd.
> >
> > The iommu selftest framework has been updated to test the IO page fault
> > delivery and response functionality.
> >
> > This series is based on the latest implementation of nested translation
> > under discussion [1] and the page fault handling framework refactoring in
> > the IOMMU core [2].
> >
> > The series and related patches are available on GitHub: [3]
> >
> > [1]https://lore.kernel.org/linux-iommu/20230921075138.124099-1-yi.l.liu@xxxxxxxxx/
> > [2]https://lore.kernel.org/linux-iommu/20230928042734.16134-1-baolu.lu@xxxxxxxxxxxxxxx/
> > [3]https://github.com/LuBaolu/intel-iommu/commits/iommufd-io-pgfault-delivery-v2
> I was working with this branch that included Yi Liu's
> wip/iommufd_nesting branch. Now Yi Lui has updated his work in this post
> https://lore.kernel.org/all/20240102143834.146165-1-yi.l.liu@xxxxxxxxx.
> Is there an updated version of the page fault work that is rebased on
> top of Liu's new version?

Yes. I am preparing the new version and will post it for discussion
after the merge window.

Best regards,
baolu