From: Alex Williamson <alex.williamson@redhat.com>
To: Nicolin Chen <nicolinc@nvidia.com>
Cc: kvm@vger.kernel.org, linux-doc@vger.kernel.org,
thierry.reding@gmail.com, will@kernel.org,
jean-philippe@linaro.org, corbet@lwn.net,
Jason Gunthorpe <jgg@nvidia.com>,
"Tian, Kevin" <kevin.tian@intel.com>,
linux-tegra@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, cohuck@redhat.com,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
robin.murphy@arm.com
Subject: Re: [RFC][PATCH v2 00/13] iommu/arm-smmu-v3: Add NVIDIA implementation
Date: Tue, 31 Aug 2021 10:15:49 -0600 [thread overview]
Message-ID: <20210831101549.237151fa.alex.williamson@redhat.com> (raw)
In-Reply-To: <20210831025923.15812-1-nicolinc@nvidia.com>
On Mon, 30 Aug 2021 19:59:10 -0700
Nicolin Chen <nicolinc@nvidia.com> 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.
We're expecting to talk more about the /dev/iommu approach at Plumbers
in few weeks. Thanks,
Alex
[1]https://lore.kernel.org/kvm/BN9PR11MB5433B1E4AE5B0480369F97178C189@BN9PR11MB5433.namprd11.prod.outlook.com/
> * 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
>
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next prev parent reply other threads:[~2021-08-31 16:16 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-31 2:59 [RFC][PATCH v2 00/13] iommu/arm-smmu-v3: Add NVIDIA implementation Nicolin Chen via iommu
2021-08-31 2:59 ` [RFC][PATCH v2 01/13] iommu: Add set_nesting_vmid/get_nesting_vmid functions Nicolin Chen via iommu
2021-08-31 2:59 ` [RFC][PATCH v2 02/13] vfio: add VFIO_IOMMU_GET_VMID and VFIO_IOMMU_SET_VMID Nicolin Chen via iommu
2021-08-31 2:59 ` [RFC][PATCH v2 03/13] vfio: Document VMID control for IOMMU Virtualization Nicolin Chen via iommu
2021-08-31 2:59 ` [RFC][PATCH v2 04/13] vfio: add set_vmid and get_vmid for vfio_iommu_type1 Nicolin Chen via iommu
2021-08-31 2:59 ` [RFC][PATCH v2 05/13] vfio/type1: Implement set_vmid and get_vmid Nicolin Chen via iommu
2021-08-31 2:59 ` [RFC][PATCH v2 06/13] vfio/type1: Set/get VMID to/from iommu driver Nicolin Chen via iommu
2021-08-31 2:59 ` [RFC][PATCH v2 07/13] iommu/arm-smmu-v3: Add shared VMID support for NESTING Nicolin Chen via iommu
2021-08-31 2:59 ` [RFC][PATCH v2 08/13] iommu/arm-smmu-v3: Add VMID alloc/free helpers Nicolin Chen via iommu
2021-08-31 2:59 ` [RFC][PATCH v2 09/13] iommu/arm-smmu-v3: Pass dev pointer to arm_smmu_detach_dev Nicolin Chen via iommu
2021-08-31 2:59 ` [RFC][PATCH v2 10/13] iommu/arm-smmu-v3: Pass cmdq pointer in arm_smmu_cmdq_issue_cmdlist() Nicolin Chen via iommu
2021-08-31 2:59 ` [RFC][PATCH v2 11/13] iommu/arm-smmu-v3: Add implementation infrastructure Nicolin Chen via iommu
2021-08-31 2:59 ` [RFC][PATCH v2 12/13] iommu/arm-smmu-v3: Add support for NVIDIA CMDQ-Virtualization hw Nicolin Chen via iommu
2021-08-31 2:59 ` [RFC][PATCH v2 13/13] iommu/nvidia-smmu-v3: Add mdev interface support Nicolin Chen via iommu
2021-08-31 16:15 ` Alex Williamson [this message]
2021-09-01 6:55 ` [RFC][PATCH v2 00/13] iommu/arm-smmu-v3: Add NVIDIA implementation Tian, Kevin
2021-09-02 14:45 ` Jason Gunthorpe via iommu
2021-09-02 22:27 ` Tian, Kevin
2021-09-16 18:21 ` Nicolin Chen via iommu
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