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Message-ID: <20240112215606.36sth724y6zcj43k@localhost>
Date: Fri, 12 Jan 2024 22:56:06 +0100
From: Joel Granados <j.granados@...sung.com>
To: Lu Baolu <baolu.lu@...ux.intel.com>
CC: Jason Gunthorpe <jgg@...pe.ca>, Kevin Tian <kevin.tian@...el.com>,
"Joerg Roedel" <joro@...tes.org>, Will Deacon <will@...nel.org>, Robin
Murphy <robin.murphy@....com>, Jean-Philippe Brucker
<jean-philippe@...aro.org>, Nicolin Chen <nicolinc@...dia.com>, Yi Liu
<yi.l.liu@...el.com>, Jacob Pan <jacob.jun.pan@...ux.intel.com>,
<iommu@...ts.linux.dev>, <linux-kselftest@...r.kernel.org>,
<virtualization@...ts.linux-foundation.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 0/6] IOMMUFD: Deliver IO page faults to user space
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@intel.com/
> [2] https://lore.kernel.org/linux-iommu/20230928042734.16134-1-baolu.lu@linux.intel.com/
> [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@intel.com.
Is there an updated version of the page fault work that is rebased on
top of Liu's new version?
Thx in advance
Best
>
> 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@linux.intel.com/
> - 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@ziepe.ca/
>
> v1: https://lore.kernel.org/linux-iommu/20230530053724.232765-1-baolu.lu@linux.intel.com/
>
> 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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