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 Does this mean the IOPF_CAPABLE HWPT needs to be parented by a HWPT created with IOMMU_HWPT_ALLOC_NEST_PARENT set? > 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 > > Best regards, > baolu > > Change log: > v2: > - Move all iommu refactoring patches into a sparated series and discuss > it in a different thread. The latest patch series [v6] is available at > https://lore.kernel.org/linux-iommu/20230928042734.16134-1-baolu.lu@xxxxxxxxxxxxxxx/ > - We discussed the timeout of the pending page fault messages. We > agreed that we shouldn't apply any timeout policy for the page fault > handling in user space. > https://lore.kernel.org/linux-iommu/20230616113232.GA84678@myrica/ > - Jason suggested that we adopt a simple file descriptor interface for > reading and responding to I/O page requests, so that user space > applications can improve performance using io_uring. > https://lore.kernel.org/linux-iommu/ZJWjD1ajeem6pK3I@xxxxxxxx/ > > v1: https://lore.kernel.org/linux-iommu/20230530053724.232765-1-baolu.lu@xxxxxxxxxxxxxxx/ > > Lu Baolu (6): > iommu: Add iommu page fault cookie helpers > iommufd: Add iommu page fault uapi data > iommufd: Initializing and releasing IO page fault data > iommufd: Deliver fault messages to user space > iommufd/selftest: Add IOMMU_TEST_OP_TRIGGER_IOPF test support > iommufd/selftest: Add coverage for IOMMU_TEST_OP_TRIGGER_IOPF > > include/linux/iommu.h | 9 + > drivers/iommu/iommu-priv.h | 15 + > drivers/iommu/iommufd/iommufd_private.h | 12 + > drivers/iommu/iommufd/iommufd_test.h | 8 + > include/uapi/linux/iommufd.h | 65 +++++ > tools/testing/selftests/iommu/iommufd_utils.h | 66 ++++- > drivers/iommu/io-pgfault.c | 50 ++++ > drivers/iommu/iommufd/device.c | 69 ++++- > drivers/iommu/iommufd/hw_pagetable.c | 260 +++++++++++++++++- > drivers/iommu/iommufd/selftest.c | 56 ++++ > tools/testing/selftests/iommu/iommufd.c | 24 +- > .../selftests/iommu/iommufd_fail_nth.c | 2 +- > 12 files changed, 620 insertions(+), 16 deletions(-) > > -- > 2.34.1 > -- Joel Granados
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