This is to add Intel VT-d nested translation based on IOMMUFD nesting infrastructure. As the iommufd nesting infrastructure series[1], iommu core supports new ops to report iommu hardware information, allocate domains with user data and sync stage-1 IOTLB. The data required in the three paths are vendor-specific, so 1) IOMMU_HW_INFO_TYPE_INTEL_VTD and struct iommu_device_info_vtd are defined to report iommu hardware information for Intel VT-d . 2) IOMMU_HWPT_DATA_VTD_S1 is defined for the Intel VT-d stage-1 page table, it will be used in the stage-1 domain allocation and IOTLB syncing path. struct iommu_hwpt_intel_vtd is defined to pass user_data for the Intel VT-d stage-1 domain allocation. struct iommu_hwpt_invalidate_intel_vtd is defined to pass the data for the Intel VT-d stage-1 IOTLB invalidation. With above IOMMUFD extensions, the intel iommu driver implements the three paths to support nested translation. The first Intel platform supporting nested translation is Sapphire Rapids which, unfortunately, has a hardware errata [2] requiring special treatment. This errata happens when a stage-1 page table page (either level) is located in a stage-2 read-only region. In that case the IOMMU hardware may ignore the stage-2 RO permission and still set the A/D bit in stage-1 page table entries during page table walking. A flag IOMMU_HW_INFO_VTD_ERRATA_772415_SPR17 is introduced to report this errata to userspace. With that restriction the user should either disable nested translation to favor RO stage-2 mappings or ensure no RO stage-2 mapping to enable nested translation. Intel-iommu driver is armed with necessary checks to prevent such mix in patch10 of this series. Qemu currently does add RO mappings though. The vfio agent in Qemu simply maps all valid regions in the GPA address space which certainly includes RO regions e.g. vbios. In reality we don't know a usage relying on DMA reads from the BIOS region. Hence finding a way to allow user opt-out RO mappings in Qemu might be an acceptable tradeoff. But how to achieve it cleanly needs more discussion in Qemu community. For now we just hacked Qemu to test. Complete code can be found in [3], QEMU could can be found in [4]. base-commit: ce9b593b1f74ccd090edc5d2ad397da84baa9946 [1] https://lore.kernel.org/linux-iommu/20230511143844.22693-1-yi.l.liu@xxxxxxxxx/ [2] https://www.intel.com/content/www/us/en/content-details/772415/content-details.html [3] https://github.com/yiliu1765/iommufd/tree/iommufd_nesting [4] https://github.com/yiliu1765/qemu/tree/wip/iommufd_rfcv4.mig.reset.v4_var3%2Bnesting Change log: v3: - Further split the patches into an order of adding helpers for nested domain, iotlb flush, nested domain attachment and nested domain allocation callback, then report the hw_info to userspace. - Add batch support in cache invalidation from userspace - Disallow nested translation usage if RO mappings exists in stage-2 domain due to errata on readonly mappings on Sapphire Rapids platform. v2: https://lore.kernel.org/linux-iommu/20230309082207.612346-1-yi.l.liu@xxxxxxxxx/ - The iommufd infrastructure is split to be separate series. v1: https://lore.kernel.org/linux-iommu/20230209043153.14964-1-yi.l.liu@xxxxxxxxx/ Regards, Yi Liu Lu Baolu (5): iommu/vt-d: Extend dmar_domain to support nested domain iommu/vt-d: Add helper for nested domain allocation iommu/vt-d: Add helper to setup pasid nested translation iommu/vt-d: Add nested domain allocation iommu/vt-d: Disallow nesting on domains with read-only mappings Yi Liu (5): iommufd: Add data structure for Intel VT-d stage-1 domain allocation iommu/vt-d: Make domain attach helpers to be extern iommu/vt-d: Set the nested domain to a device iommu/vt-d: Add iotlb flush for nested domain iommu/vt-d: Implement hw_info for iommu capability query drivers/iommu/intel/Makefile | 2 +- drivers/iommu/intel/iommu.c | 78 ++++++++++++--- drivers/iommu/intel/iommu.h | 55 +++++++++-- drivers/iommu/intel/nested.c | 181 +++++++++++++++++++++++++++++++++++ drivers/iommu/intel/pasid.c | 151 +++++++++++++++++++++++++++++ drivers/iommu/intel/pasid.h | 2 + drivers/iommu/iommufd/main.c | 6 ++ include/linux/iommu.h | 1 + include/uapi/linux/iommufd.h | 149 ++++++++++++++++++++++++++++ 9 files changed, 603 insertions(+), 22 deletions(-) create mode 100644 drivers/iommu/intel/nested.c -- 2.34.1
