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    Subject[PATCH v6 0/6] iommufd: Add nesting infrastructure (part 2/2)
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    Nested translation is a hardware feature that is supported by many modern
    IOMMU hardwares. It has two stages (stage-1, stage-2) address translation
    to get access to the physical address. stage-1 translation table is owned
    by userspace (e.g. by a guest OS), while stage-2 is owned by kernel. Changes
    to stage-1 translation table should be followed by an IOTLB invalidation.

    Take Intel VT-d as an example, the stage-1 translation table is I/O page
    table. As the below diagram shows, guest I/O page table pointer in GPA
    (guest physical address) is passed to host and be used to perform the stage-1
    address translation. Along with it, modifications to present mappings in the
    guest I/O page table should be followed with an IOTLB invalidation.

    .-------------. .---------------------------.
    | vIOMMU | | Guest I/O page table |
    | | '---------------------------'
    .----------------/
    | PASID Entry |--- PASID cache flush --+
    '-------------' |
    | | V
    | | I/O page table pointer in GPA
    '-------------'
    Guest
    ------| Shadow |---------------------------|--------
    v v v
    Host
    .-------------. .------------------------.
    | pIOMMU | | FS for GIOVA->GPA |
    | | '------------------------'
    .----------------/ |
    | PASID Entry | V (Nested xlate)
    '----------------\.----------------------------------.
    | | | SS for GPA->HPA, unmanaged domain|
    | | '----------------------------------'
    '-------------'
    Where:
    - FS = First stage page tables
    - SS = Second stage page tables
    <Intel VT-d Nested translation>

    This series adds the cache invalidation path for the userspace to invalidate
    cache after modifying the stage-1 page table. This is based on the first part
    of nesting [1]

    Complete code can be found in [2], QEMU could can be found in [3].

    At last, this is a team work together with Nicolin Chen, Lu Baolu. Thanks
    them for the help. ^_^. Look forward to your feedbacks.

    [1] https://lore.kernel.org/linux-iommu/20231026044216.64964-1-yi.l.liu@intel.com/ - merged
    [2] https://github.com/yiliu1765/iommufd/tree/iommufd_nesting
    [3] https://github.com/yiliu1765/qemu/tree/zhenzhong/wip/iommufd_nesting_rfcv1

    Change log:

    v6:
    - No much change, just rebase on top of 6.7-rc1 as part 1/2 is merged

    v5: https://lore.kernel.org/linux-iommu/20231020092426.13907-1-yi.l.liu@intel.com/#t
    - Split the iommufd nesting series into two parts of alloc_user and
    invalidation (Jason)
    - Split IOMMUFD_OBJ_HW_PAGETABLE to IOMMUFD_OBJ_HWPT_PAGING/_NESTED, and
    do the same with the structures/alloc()/abort()/destroy(). Reworked the
    selftest accordingly too. (Jason)
    - Move hwpt/data_type into struct iommu_user_data from standalone op
    arguments. (Jason)
    - Rename hwpt_type to be data_type, the HWPT_TYPE to be HWPT_ALLOC_DATA,
    _TYPE_DEFAULT to be _ALLOC_DATA_NONE (Jason, Kevin)
    - Rename iommu_copy_user_data() to iommu_copy_struct_from_user() (Kevin)
    - Add macro to the iommu_copy_struct_from_user() to calculate min_size
    (Jason)
    - Fix two bugs spotted by ZhaoYan

    v4: https://lore.kernel.org/linux-iommu/20230921075138.124099-1-yi.l.liu@intel.com/
    - Separate HWPT alloc/destroy/abort functions between user-managed HWPTs
    and kernel-managed HWPTs
    - Rework invalidate uAPI to be a multi-request array-based design
    - Add a struct iommu_user_data_array and a helper for driver to sanitize
    and copy the entry data from user space invalidation array
    - Add a patch fixing TEST_LENGTH() in selftest program
    - Drop IOMMU_RESV_IOVA_RANGES patches
    - Update kdoc and inline comments
    - Drop the code to add IOMMU_RESV_SW_MSI to kernel-managed HWPT in nested translation,
    this does not change the rule that resv regions should only be added to the
    kernel-managed HWPT. The IOMMU_RESV_SW_MSI stuff will be added in later series
    as it is needed only by SMMU so far.

    v3: https://lore.kernel.org/linux-iommu/20230724110406.107212-1-yi.l.liu@intel.com/
    - Add new uAPI things in alphabetical order
    - Pass in "enum iommu_hwpt_type hwpt_type" to op->domain_alloc_user for
    sanity, replacing the previous op->domain_alloc_user_data_len solution
    - Return ERR_PTR from domain_alloc_user instead of NULL
    - Only add IOMMU_RESV_SW_MSI to kernel-managed HWPT in nested translation (Kevin)
    - Add IOMMU_RESV_IOVA_RANGES to report resv iova ranges to userspace hence
    userspace is able to exclude the ranges in the stage-1 HWPT (e.g. guest I/O
    page table). (Kevin)
    - Add selftest coverage for the new IOMMU_RESV_IOVA_RANGES ioctl
    - Minor changes per Kevin's inputs

    v2: https://lore.kernel.org/linux-iommu/20230511143844.22693-1-yi.l.liu@intel.com/
    - Add union iommu_domain_user_data to include all user data structures to avoid
    passing void * in kernel APIs.
    - Add iommu op to return user data length for user domain allocation
    - Rename struct iommu_hwpt_alloc::data_type to be hwpt_type
    - Store the invalidation data length in iommu_domain_ops::cache_invalidate_user_data_len
    - Convert cache_invalidate_user op to be int instead of void
    - Remove @data_type in struct iommu_hwpt_invalidate
    - Remove out_hwpt_type_bitmap in struct iommu_hw_info hence drop patch 08 of v1

    v1: https://lore.kernel.org/linux-iommu/20230309080910.607396-1-yi.l.liu@intel.com/

    Thanks,
    Yi Liu

    Lu Baolu (1):
    iommu: Add cache_invalidate_user op

    Nicolin Chen (4):
    iommu: Add iommu_copy_struct_from_user_array helper
    iommufd/selftest: Add mock_domain_cache_invalidate_user support
    iommufd/selftest: Add IOMMU_TEST_OP_MD_CHECK_IOTLB test op
    iommufd/selftest: Add coverage for IOMMU_HWPT_INVALIDATE ioctl

    Yi Liu (1):
    iommufd: Add IOMMU_HWPT_INVALIDATE

    drivers/iommu/iommufd/hw_pagetable.c | 35 ++++++++
    drivers/iommu/iommufd/iommufd_private.h | 9 ++
    drivers/iommu/iommufd/iommufd_test.h | 22 +++++
    drivers/iommu/iommufd/main.c | 3 +
    drivers/iommu/iommufd/selftest.c | 69 +++++++++++++++
    include/linux/iommu.h | 84 +++++++++++++++++++
    include/uapi/linux/iommufd.h | 35 ++++++++
    tools/testing/selftests/iommu/iommufd.c | 75 +++++++++++++++++
    tools/testing/selftests/iommu/iommufd_utils.h | 63 ++++++++++++++
    9 files changed, 395 insertions(+)

    --
    2.34.1

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