iommufd gives userspace the capability to manipulate iommu subsytem. e.g. DMA map/unmap etc. In the near future, it will support iommu nested translation. Different platform vendors have different implementations for the nested translation. For example, Intel VT-d supports using guest I/O page table as the stage-1 translation table. This requires guest I/O page table be compatible with hardware IOMMU. So before set up nested translation, userspace needs to know the hardware iommu information to understand the nested translation requirements.
This series reports the iommu hardware information for a given device which has been bound to iommufd. It is preparation work for userspace to allocate hwpt for given device. Like the nested translation support[1].
This series introduces an iommu op to report the iommu hardware info, and an ioctl IOMMU_GET_HW_INFO is added to report such hardware info to user. enum iommu_hw_info_type is defined to differentiate the iommu hardware info reported to user hence user can decode them. This series adds the framework for iommu hw info reporting, and adds the vtd implementation. The complete code is available in [1].
[1] https://github.com/yiliu1765/iommufd/tree/iommufd_hw_info-v8
Change log:
v8: - Updated the uAPI by allowing a 0 value at the input @data_len - Changed to always report the kernel supported data length instead of the length that kernel filled in the user space buffer - Updated uAPI doc accordingly - Add one more selftest for 0 value @data_len and also check the output @data_len with the size kernel supports - Fix the usage of clear_user() - Rebase on top of Jason's for-next branch (base: 65aaca1 iommufd: Remove iommufd_ref_to_users()) - Include the vtd hw_info implementation from vtd nesting series https://lore.kernel.org/r/20230724111335.107427-12-yi.l.liu@intel.com
v7: https://lore.kernel.org/linux-iommu/20230811071501.4126-1-yi.l.liu@intel.com... - Use clear_user() (Jason) - Add fail_nth for hw_ifo (Jason)
v6: https://lore.kernel.org/linux-iommu/20230808153510.4170-1-yi.l.liu@intel.com... - Add Jingqi's comment on patch 02 - Add Baolu's r-b to patch 03 - Address Jason's comment on patch 03
v5: https://lore.kernel.org/linux-iommu/20230803143144.200945-1-yi.l.liu@intel.c... - Return hw_info_type in the .hw_info op, hence drop hw_info_type field in iommu_ops (Kevin) - Add Jason's r-b for patch 01 - Address coding style comments from Jason and Kevin w.r.t. patch 02, 03 and 04
v4: https://lore.kernel.org/linux-iommu/20230724105936.107042-1-yi.l.liu@intel.c... - Rename ioctl to IOMMU_GET_HW_INFO and structure to iommu_hw_info - Move the iommufd_get_hw_info handler to main.c - Place iommu_hw_info prior to iommu_hwpt_alloc - Update the function namings accordingly - Update uapi kdocs
v3: https://lore.kernel.org/linux-iommu/20230511143024.19542-1-yi.l.liu@intel.co... - Add r-b from Baolu - Rename IOMMU_HW_INFO_TYPE_DEFAULT to be IOMMU_HW_INFO_TYPE_NONE to better suit what it means - Let IOMMU_DEVICE_GET_HW_INFO succeed even the underlying iommu driver does not have driver-specific data to report per below remark. https://lore.kernel.org/kvm/ZAcwJSK%2F9UVI9LXu@nvidia.com/
v2: https://lore.kernel.org/linux-iommu/20230309075358.571567-1-yi.l.liu@intel.c... - Drop patch 05 of v1 as it is already covered by other series - Rename the capability info to be iommu hardware info
v1: https://lore.kernel.org/linux-iommu/20230209041642.9346-1-yi.l.liu@intel.com...
Regards, Yi Liu
Lu Baolu (1): iommu: Add new iommu op to get iommu hardware information
Nicolin Chen (1): iommufd/selftest: Add coverage for IOMMU_GET_HW_INFO ioctl
Yi Liu (3): iommu: Move dev_iommu_ops() to private header iommufd: Add IOMMU_GET_HW_INFO iommu/vt-d: Implement hw_info for iommu capability query
drivers/iommu/intel/iommu.c | 19 +++++ drivers/iommu/iommu-priv.h | 11 +++ drivers/iommu/iommufd/device.c | 73 ++++++++++++++++++ drivers/iommu/iommufd/iommufd_private.h | 1 + drivers/iommu/iommufd/iommufd_test.h | 9 +++ drivers/iommu/iommufd/main.c | 3 + drivers/iommu/iommufd/selftest.c | 16 ++++ include/linux/iommu.h | 20 +++-- include/uapi/linux/iommufd.h | 74 +++++++++++++++++++ tools/testing/selftests/iommu/iommufd.c | 30 +++++++- .../selftests/iommu/iommufd_fail_nth.c | 4 + tools/testing/selftests/iommu/iommufd_utils.h | 56 ++++++++++++++ 12 files changed, 304 insertions(+), 12 deletions(-)