Re: [PATCH RFC v1 00/15] iommu/virtio: Nested stage support with Arm

Auger Eric
2021-01-19T09:08:25Z

Hi Vivek,

On 1/15/21 1:13 PM, Vivek Gautam wrote:
> This patch-series aims at enabling Nested stage translation in guests
> using virtio-iommu as the paravirtualized iommu. The backend is supported
> with Arm SMMU-v3 that provides nested stage-1 and stage-2 translation.
>
> This series derives its purpose from various efforts happening to add
> support for Shared Virtual Addressing (SVA) in host and guest. On Arm,
> most of the support for SVA has already landed. The support for nested
> stage translation and fault reporting to guest has been proposed [1].
> The related changes required in VFIO [2] framework have also been put
> forward.
>
> This series proposes changes in virtio-iommu to program PASID tables
> and related stage-1 page tables. A simple iommu-pasid-table library
> is added for this purpose that interacts with vendor drivers to
> allocate and populate PASID tables.
> In Arm SMMUv3 we propose to pull the Context Descriptor (CD) management
> code out of the arm-smmu-v3 driver and add that as a glue vendor layer
> to support allocating CD tables, and populating them with right values.
> These CD tables are essentially the PASID tables and contain stage-1
> page table configurations too.
> A request to setup these CD tables come from virtio-iommu driver using
> the iommu-pasid-table library when running on Arm. The virtio-iommu
> then pass these PASID tables to the host using the right virtio backend
> and support in VMM.
>
> For testing we have added necessary support in kvmtool. The changes in
> kvmtool are based on virtio-iommu development branch by Jean-Philippe
> Brucker [3].
>
> The tested kernel branch contains following in the order bottom to top
> on the git hash -
> a) v5.11-rc3
> b) arm-smmu-v3 [1] and vfio [2] changes from Eric to add nested page
> table support for Arm.
> c) Smmu test engine patches from Jean-Philippe's branch [4]
> d) This series
> e) Domain nesting info patches [5][6][7].
> f) Changes to add arm-smmu-v3 specific nesting info (to be sent to
> the list).
>
> This kernel is tested on Neoverse reference software stack with
> Fixed virtual platform. Public version of the software stack and
> FVP is available here[8][9].
>
> A big thanks to Jean-Philippe for his contributions towards this work
> and for his valuable guidance.
>
> [1] https://lore.kernel.org/linux-iommu/20201118112151.25412-1-eric.auger@redhat.com/T/
> [2] https://lore.kernel.org/kvmarm/20201116110030.32335-12-eric.auger@redhat.com/T/
> [3] https://jpbrucker.net/git/kvmtool/log/?h=virtio-iommu/devel
> [4] https://jpbrucker.net/git/linux/log/?h=sva/smmute
> [5] https://lore.kernel.org/kvm/1599734733-6431-2-git-send-email-yi.l.liu@intel.com/
> [6] https://lore.kernel.org/kvm/1599734733-6431-3-git-send-email-yi.l.liu@intel.com/
> [7] https://lore.kernel.org/kvm/1599734733-6431-4-git-send-email-yi.l.liu@intel.com/
> [8] https://developer.arm.com/tools-and-software/open-source-software/arm-platforms-software/arm-ecosystem-fvps
> [9] https://git.linaro.org/landing-teams/working/arm/arm-reference-platforms.git/about/docs/rdn1edge/user-guide.rst

Could you share a public branch where we could find all the kernel pieces.

Thank you in advance

Best Regards

Eric
>
> Jean-Philippe Brucker (6):
> iommu/virtio: Add headers for table format probing
> iommu/virtio: Add table format probing
> iommu/virtio: Add headers for binding pasid table in iommu
> iommu/virtio: Add support for INVALIDATE request
> iommu/virtio: Attach Arm PASID tables when available
> iommu/virtio: Add support for Arm LPAE page table format
>
> Vivek Gautam (9):
> iommu/arm-smmu-v3: Create a Context Descriptor library
> iommu: Add a simple PASID table library
> iommu/arm-smmu-v3: Update drivers to work with iommu-pasid-table
> iommu/arm-smmu-v3: Update CD base address info for user-space
> iommu/arm-smmu-v3: Set sync op from consumer driver of cd-lib
> iommu: Add asid_bits to arm smmu-v3 stage1 table info
> iommu/virtio: Update table format probing header
> iommu/virtio: Prepare to add attach pasid table infrastructure
> iommu/virtio: Update fault type and reason info for viommu fault
>
> drivers/iommu/arm/arm-smmu-v3/Makefile | 2 +-
> .../arm/arm-smmu-v3/arm-smmu-v3-cd-lib.c | 283 +++++++
> .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 16 +-
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 268 +------
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 4 +-
> drivers/iommu/iommu-pasid-table.h | 140 ++++
> drivers/iommu/virtio-iommu.c | 692 +++++++++++++++++-
> include/uapi/linux/iommu.h | 2 +-
> include/uapi/linux/virtio_iommu.h | 158 +++-
> 9 files changed, 1303 insertions(+), 262 deletions(-)
> create mode 100644 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-cd-lib.c
> create mode 100644 drivers/iommu/iommu-pasid-table.h
>