Messages in this thread | | | From | Eric Auger <> | Subject | [PATCH v8 0/7] KVM PCIe/MSI passthrough on ARM/ARM64: kernel part 3/3: vfio changes | Date | Thu, 28 Apr 2016 08:28:31 +0000 |
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This series allows the user-space to register a reserved IOVA domain. This completes the kernel integration of the whole functionality on top of part 1 & 2.
It also depends on [PATCH 1/3] iommu: Add MMIO mapping type series, http://comments.gmane.org/gmane.linux.kernel.iommu/12869
We reuse the VFIO DMA MAP ioctl with a new flag to bridge to the msi-iommu API. The need for provisioning such MSI IOVA range is reported through the VFIO_IOMMU_GET_INFO iotcl.
vfio_iommu_type1 checks if the MSI mapping is safe when attaching the vfio group to the container (allow_unsafe_interrupts modality).
On ARM/ARM64, the IOMMU does not astract IRQ remapping. the modality is abstracted on MSI controller side. The GICv3 ITS is the first controller advertising the modality.
More details & context can be found at: http://www.linaro.org/blog/core-dump/kvm-pciemsi-passthrough-armarm64/
Best Regards
Eric
Testing: - functional on ARM64 AMD Overdrive HW (single GICv2m frame) with Intel X540-T2 (SR-IOV capable) - Not tested: ARM GICv3 ITS
References: [1] [RFC 0/2] VFIO: Add virtual MSI doorbell support (https://lkml.org/lkml/2015/7/24/135) [2] [RFC PATCH 0/6] vfio: Add interface to map MSI pages (https://lists.cs.columbia.edu/pipermail/kvmarm/2015-September/016607.html) [3] [PATCH v2 0/3] Introduce MSI hardware mapping for VFIO (http://permalink.gmane.org/gmane.comp.emulators.kvm.arm.devel/3858)
Git: complete series available at https://git.linaro.org/people/eric.auger/linux.git/shortlog/refs/heads/v4.6-rc5-pcie-passthrough-v8
previous version at https://git.linaro.org/people/eric.auger/linux.git/shortlog/refs/heads/v4.6-rc4-pcie-passthrough-v7
QEMU Integration: [RFC v2 0/8] KVM PCI/MSI passthrough with mach-virt (http://lists.gnu.org/archive/html/qemu-arm/2016-01/msg00444.html) https://git.linaro.org/people/eric.auger/qemu.git/shortlog/refs/heads/v2.5.0-pci-passthrough-rfc-v2
History: v7 -> v8: - use renamed msi-iommu API - VFIO only responsible for setting the IOVA aperture - use new DOMAIN_ATTR_MSI_GEOMETRY iommu domain attribute
v6 -> v7: - vfio_find_dma now accepts a dma_type argument. - should have recovered the capability to unmap the whole user IOVA range - remove computation of nb IOVA pages -> will post a separate RFC for that while respinning the QEMU part
RFC v5 -> patch v6: - split to ease the review process
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): vfio: introduce a vfio_dma type field vfio/type1: vfio_find_dma accepting a type argument vfio/type1: bypass unmap/unpin and replay for VFIO_IOVA_RESERVED slots vfio: allow reserved msi iova registration vfio/type1: also check IRQ remapping capability at msi domain iommu/arm-smmu: do not advertise IOMMU_CAP_INTR_REMAP vfio/type1: return MSI mapping requirements with VFIO_IOMMU_GET_INFO
drivers/iommu/arm-smmu-v3.c | 3 +- drivers/iommu/arm-smmu.c | 3 +- drivers/vfio/vfio_iommu_type1.c | 227 +++++++++++++++++++++++++++++++++++++--- include/uapi/linux/vfio.h | 14 ++- 4 files changed, 230 insertions(+), 17 deletions(-)
-- 1.9.1
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