> From: Alex Williamson > Sent: Wednesday, September 1, 2021 12:16 AM > > On Mon, 30 Aug 2021 19:59:10 -0700 > Nicolin Chen <nicolinc@xxxxxxxxxx> wrote: > > > The SMMUv3 devices implemented in the Grace SoC support NVIDIA's > custom > > CMDQ-Virtualization (CMDQV) hardware. Like the new ECMDQ feature first > > introduced in the ARM SMMUv3.3 specification, CMDQV adds multiple > VCMDQ > > interfaces to supplement the single architected SMMU_CMDQ in an effort > > to reduce contention. > > > > This series of patches add CMDQV support with its preparational changes: > > > > * PATCH-1 to PATCH-8 are related to shared VMID feature: they are used > > first to improve TLB utilization, second to bind a shared VMID with a > > VCMDQ interface for hardware configuring requirement. > > The vfio changes would need to be implemented in alignment with the > /dev/iommu proposals[1]. AIUI, the VMID is essentially binding > multiple containers together for TLB invalidation, which I expect in > the proposal below is largely already taken care of in that a single > iommu-fd can support multiple I/O address spaces and it's largely > expected that a hypervisor would use a single iommu-fd so this explicit > connection by userspace across containers wouldn't be necessary. Agree. VMID is equivalent to DID (domain id) in other vendor iommus. with /dev/iommu multiple I/O address spaces can share the same VMID via nesting. No need of exposing VMID to userspace to build the connection. Thanks, Kevin > > We're expecting to talk more about the /dev/iommu approach at Plumbers > in few weeks. Thanks, > > Alex > > [1]https://lore.kernel.org/kvm/BN9PR11MB5433B1E4AE5B0480369F97178C1 > 89@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ > > > > * PATCH-9 and PATCH-10 are to accommodate the NVIDIA implementation > with > > the existing arm-smmu-v3 driver. > > > > * PATCH-11 borrows the "implementation infrastructure" from the arm- > smmu > > driver so later change can build upon it. > > > > * PATCH-12 adds an initial NVIDIA implementation related to host feature, > > and also adds implementation specific ->device_reset() and ->get_cmdq() > > callback functions. > > > > * PATCH-13 adds virtualization features using VFIO mdev interface, which > > allows user space hypervisor to map and get access to one of the VCMDQ > > interfaces of CMDQV module. > > > > ( Thinking that reviewers can get a better view of this implementation, > > I am attaching QEMU changes here for reference purpose: > > https://github.com/nicolinc/qemu/commits/dev/cmdqv_v6.0.0-rc2 > > The branch has all preparational changes, while I'm still integrating > > device model and ARM-VIRT changes, and will push them these two days, > > although they might not be in a good shape of being sent to review yet ) > > > > Above all, I marked RFC for this series, as I feel that we may come up > > some better solution. So please kindly share your reviews and insights. > > > > Thank you! > > > > Changelog > > v1->v2: > > * Added mdev interface support for hypervisor and VMs. > > * Added preparational changes for mdev interface implementation. > > * PATCH-12 Changed ->issue_cmdlist() to ->get_cmdq() for a better > > integration with recently merged ECMDQ-related changes. > > > > Nate Watterson (3): > > iommu/arm-smmu-v3: Add implementation infrastructure > > iommu/arm-smmu-v3: Add support for NVIDIA CMDQ-Virtualization hw > > iommu/nvidia-smmu-v3: Add mdev interface support > > > > Nicolin Chen (10): > > iommu: Add set_nesting_vmid/get_nesting_vmid functions > > vfio: add VFIO_IOMMU_GET_VMID and VFIO_IOMMU_SET_VMID > > vfio: Document VMID control for IOMMU Virtualization > > vfio: add set_vmid and get_vmid for vfio_iommu_type1 > > vfio/type1: Implement set_vmid and get_vmid > > vfio/type1: Set/get VMID to/from iommu driver > > iommu/arm-smmu-v3: Add shared VMID support for NESTING > > iommu/arm-smmu-v3: Add VMID alloc/free helpers > > iommu/arm-smmu-v3: Pass dev pointer to arm_smmu_detach_dev > > iommu/arm-smmu-v3: Pass cmdq pointer in > arm_smmu_cmdq_issue_cmdlist() > > > > Documentation/driver-api/vfio.rst | 34 + > > MAINTAINERS | 2 + > > drivers/iommu/arm/arm-smmu-v3/Makefile | 2 +- > > .../iommu/arm/arm-smmu-v3/arm-smmu-v3-impl.c | 15 + > > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 121 +- > > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 18 + > > .../iommu/arm/arm-smmu-v3/nvidia-smmu-v3.c | 1249 > +++++++++++++++++ > > drivers/iommu/iommu.c | 20 + > > drivers/vfio/vfio.c | 25 + > > drivers/vfio/vfio_iommu_type1.c | 37 + > > include/linux/iommu.h | 5 + > > include/linux/vfio.h | 2 + > > include/uapi/linux/vfio.h | 26 + > > 13 files changed, 1537 insertions(+), 19 deletions(-) > > create mode 100644 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3- > impl.c > > create mode 100644 drivers/iommu/arm/arm-smmu-v3/nvidia-smmu-v3.c > > > > _______________________________________________ > iommu mailing list > iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx > https://lists.linuxfoundation.org/mailman/listinfo/iommu
