Add substreams and PCI PASID support to the SMMUv3 driver. At the moment the driver supports a single address space per device. PASID enables multiple address spaces per device, up to a million in theory (1 << 20). Two kernel features will make use of PASIDs, auxiliary domains (AUXD) and Shared Virtual Addressing (SVA). Auxiliary domains allow to program PASID contexts using IOMMU domains. SVA allows to bind process address spaces to device contexts and relieve device drivers of DMA management. Since SVA support for SMMUv3 has a lot more dependencies (new fault API, ASID pinning, generic bind, PRI or stall support, and so on), introducing PASID support to the SMMUv3 driver is easier with auxiliary domains. The AUXD API allows device drivers to easily test PASID support of their devices, although they need to allocate IOVA and pages themselves because the DMA API doesn't support AUXD for the moment: iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_AUX); domain = iommu_domain_alloc(dev->bus); iommu_aux_attach_device(domain, dev); iommu_map(domain, iova, phys_addr, size, prot); pasid = iommu_aux_get_pasid(domain); /* Then launch DMA with the PASID and IOVA */ Auxiliary domains also allow to split devices into multiple contexts assignable to guest, with vfio-mdev. Past discussions for these patches: * Auxiliary domains (patch 6) [RFC PATCH 0/6] Auxiliary IOMMU domains and Arm SMMUv3 https://www.spinics.net/lists/iommu/msg30637.html * SSID support for the SMMU (patches 2, 3, 4, 5, 7 and 8) [PATCH v2 00/40] Shared Virtual Addressing for the IOMMU https://lists.linuxfoundation.org/pipermail/iommu/2018-May/027595.html * I/O ASID (patch 1) [PATCH v3 00/16] Shared virtual address IOMMU and VT-d support https://lkml.kernel.org/lkml/1556922737-76313-4-git-send-email-jacob.jun.pan@xxxxxxxxxxxxxxx/ Jean-Philippe Brucker (8): iommu: Add I/O ASID allocator dt-bindings: document PASID property for IOMMU masters iommu/arm-smmu-v3: Support platform SSID iommu/arm-smmu-v3: Add support for Substream IDs iommu/arm-smmu-v3: Add second level of context descriptor table iommu/arm-smmu-v3: Support auxiliary domains iommu/arm-smmu-v3: Improve add_device() error handling iommu/arm-smmu-v3: Add support for PCI PASID .../devicetree/bindings/iommu/iommu.txt | 6 + drivers/iommu/Kconfig | 5 + drivers/iommu/Makefile | 1 + drivers/iommu/arm-smmu-v3.c | 714 ++++++++++++++++-- drivers/iommu/ioasid.c | 150 ++++ drivers/iommu/of_iommu.c | 6 +- include/linux/ioasid.h | 49 ++ include/linux/iommu.h | 1 + 8 files changed, 865 insertions(+), 67 deletions(-) create mode 100644 drivers/iommu/ioasid.c create mode 100644 include/linux/ioasid.h -- 2.21.0
