This series introduces the dma-reserved-iommu api used to: - create/destroy an iova domain dedicated to reserved iova bindings - map/unmap physical addresses onto reserved IOVAs. - unmap and destroy all IOVA reserved bindings Currently reserved IOVAs are meant to map MSI physical doorbells. A single reserved domain does exit per domain. Also a new domain attribute is introduced to signal whether the MSI addresses must be mapped in the IOMMU VFIO subsystem is supposed to create/destroy the iommu reserved domain. When the MSI sub-system is about to handle an MSI physical address that needs to be bound, it uses the dma-reserved_iommu API to map/unmap the address. Since several drivers are likely to use the same doorbell, a reference counting must exist on the bindings. An RB-tree indexed by PA is used. More details & context can be found at: http://www.linaro.org/blog/core-dump/kvm-pciemsi-passthrough-armarm64/ Best Regards Eric Git: complete series available at https://git.linaro.org/people/eric.auger/linux.git/shortlog/refs/heads/v4.6-rc1-pcie-passthrough-v6 History: RFC v5 -> patch v6: - split to ease the review process - in dma-reserved-api use a spin lock instead of a mutex (reported by Jean-Philippe) - revisit iommu_get_reserved_iova API to pass a size parameter upon Marc's request - Consistently use the page order passed when creating the iova domain. - init reserved_binding_list (reported by Julien) RFC v4 -> RFC v5: - take into account Thomas' comments on MSI related patches - split "msi: IOMMU map the doorbell address when needed" - increase readability and add comments - fix style issues - split "iommu: Add DOMAIN_ATTR_MSI_MAPPING attribute" - platform ITS now advertises IOMMU_CAP_INTR_REMAP - fix compilation issue with CONFIG_IOMMU API unset - arm-smmu-v3 now advertises DOMAIN_ATTR_MSI_MAPPING RFC v3 -> v4: - Move doorbell mapping/unmapping in msi.c - fix ref count issue on set_affinity: in case of a change in the address the previous address is decremented - doorbell map/unmap now is done on msi composition. Should allow the use case for platform MSI controllers - create dma-reserved-iommu.h/c exposing/implementing a new API dedicated to reserved IOVA management (looking like dma-iommu glue) - series reordering to ease the review: - first part is related to IOMMU - second related to MSI sub-system - third related to VFIO (except arm-smmu IOMMU_CAP_INTR_REMAP removal) - expose the number of requested IOVA pages through VFIO_IOMMU_GET_INFO [this partially addresses Marc's comments on iommu_get/put_single_reserved size/alignment problematic - which I did not ignore - but I don't know how much I can do at the moment] RFC v2 -> RFC v3: - should fix wrong handling of some CONFIG combinations: CONFIG_IOVA, CONFIG_IOMMU_API, CONFIG_PCI_MSI_IRQ_DOMAIN - fix MSI_FLAG_IRQ_REMAPPING setting in GICv3 ITS (although not tested) PATCH v1 -> RFC v2: - reverted to RFC since it looks more reasonable ;-) the code is split between VFIO, IOMMU, MSI controller and I am not sure I did the right choices. Also API need to be further discussed. - iova API usage in arm-smmu.c. - MSI controller natively programs the MSI addr with either the PA or IOVA. This is not done anymore in vfio-pci driver as suggested by Alex. - check irq remapping capability of the group RFC v1 [2] -> PATCH v1: - use the existing dma map/unmap ioctl interface with a flag to register a reserved IOVA range. Use the legacy Rb to store this special vfio_dma. - a single reserved IOVA contiguous region now is allowed - use of an RB tree indexed by PA to store allocated reserved slots - use of a vfio_domain iova_domain to manage iova allocation within the window provided by the userspace - vfio alloc_map/unmap_free take a vfio_group handle - vfio_group handle is cached in vfio_pci_device - add ref counting to bindings - user modality enabled at the end of the series Eric Auger (7): iommu: Add DOMAIN_ATTR_MSI_MAPPING attribute iommu/arm-smmu: advertise DOMAIN_ATTR_MSI_MAPPING attribute iommu: introduce a reserved iova cookie dma-reserved-iommu: alloc/free_reserved_iova_domain dma-reserved-iommu: reserved binding rb-tree and helpers dma-reserved-iommu: iommu_get/put_single_reserved dma-reserved-iommu: iommu_unmap_reserved drivers/iommu/Kconfig | 8 + drivers/iommu/Makefile | 1 + drivers/iommu/arm-smmu-v3.c | 2 + drivers/iommu/arm-smmu.c | 2 + drivers/iommu/dma-reserved-iommu.c | 321 +++++++++++++++++++++++++++++++++++++ drivers/iommu/iommu.c | 2 + include/linux/dma-reserved-iommu.h | 80 +++++++++ include/linux/iommu.h | 7 + 8 files changed, 423 insertions(+) create mode 100644 drivers/iommu/dma-reserved-iommu.c create mode 100644 include/linux/dma-reserved-iommu.h -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
