Re: [PATCH 0/5] Convert virtio-iommu to domain_alloc_paging()

Jacob Pan
2025-02-12T00:41:54Z

Hi Jason,

On Fri, 7 Feb 2025 10:46:00 -0400
Jason Gunthorpe <jgg@nvidia.com> wrote:

> virtio-iommu and fsl_pamu are the only two drivers left that still
> rely on ops.domain_alloc()
>
> Update virtio-iommu to have a global static identity domain, implement
> domain_alloc_paging(), and finalize its domain during allocation
> instead of on first attach.
>
> As virtio-iommu was the last real iommu driver using domain_alloc()
> update the core code to isolate the remains to fsl_pamu.
>
> I tested this using qemu x86 7.0.0 and 9.2.0 with a mlx5 VFIO PCI
> device. The kernel behaves the same after this series.
>
> However, there seem to be some unrelated qemu bugs. 7.0.0 does not
> have working VIRTIO_IOMMU_F_BYPASS_CONFIG and neither qemu works with
> an IDENTITY domain using !VIRTIO_IOMMU_F_BYPASS_CONFIG. It prints:
>
> qemu-system-x86_64: iommu has granularity incompatible with target AS
> qemu-system-x86_64: iommu map to non memory area 80000000
> qemu-system-x86_64: iommu map to non memory area c0000000
> qemu-system-x86_64: iommu map to non memory area e0000000
> qemu-system-x86_64: iommu map to non memory area f0000000
> qemu-system-x86_64: iommu map to non memory area f8000000
> qemu-system-x86_64: iommu map to non memory area fc000000
> qemu-system-x86_64: iommu map to non memory area fe000000
> qemu-system-x86_64: iommu map to non memory area fe800000
> qemu-system-x86_64: iommu map to non memory area 0
> qemu-system-x86_64: iommu map to non memory area fef00000
> qemu-system-x86_64: iommu map to non memory area ff000000
> qemu-system-x86_64: iommu has granularity incompatible with target AS
> qemu-system-x86_64: iommu map to non memory area 200000000
> qemu-system-x86_64: iommu map to non memory area 400000000
> qemu-system-x86_64: iommu map to non memory area 800000000
> qemu-system-x86_64: iommu map to non memory area 1000000000
> qemu-system-x86_64: iommu map to non memory area 2000000000
> qemu-system-x86_64: iommu map to non memory area 4000000000

I see the same on arm64 with v9.0, assigned an ixgbe nic via VFIO.

qemu-system-aarch64: iommu map to non memory area 0
qemu-system-aarch64: iommu map to non memory area 8100000
qemu-system-aarch64: iommu map to non memory area 8200000
qemu-system-aarch64: iommu map to non memory area 8400000
qemu-system-aarch64: iommu map to non memory area 8800000
qemu-system-aarch64: iommu map to non memory area 0
qemu-system-aarch64: iommu map to non memory area 0
qemu-system-aarch64: iommu map to non memory area c000000
qemu-system-aarch64: iommu map to non memory area 10000000
qemu-system-aarch64: iommu map to non memory area 20000000
qemu-system-aarch64: iommu has granularity incompatible with target AS
qemu-system-aarch64: iommu map to non memory area 200000000
qemu-system-aarch64: iommu map to non memory area 400000000
qemu-system-aarch64: iommu map to non memory area 800000000
qemu-system-aarch64: iommu map to non memory area 1000000000
qemu-system-aarch64: iommu map to non memory area 2000000000
qemu-system-aarch64: iommu map to non memory area 4000000000
qemu-system-aarch64: iommu map to non memory area 8000000000
qemu-system-aarch64: iommu map to non memory area 10000000000
qemu-system-aarch64: iommu map to non memory area 20000000000
qemu-system-aarch64: iommu map to non memory area 40000000000
qemu-system-aarch64: iommu map to non memory area 80000000000
qemu-system-aarch64: iommu map to non memory area 100000000000
qemu-system-aarch64: iommu map to non memory area 200000000000
qemu-system-aarch64: iommu map to non memory area 400000000000
qemu-system-aarch64: iommu map to non memory area 800000000000

> Jason Gunthorpe (5):
> iommu/virtio: Break out bypass identity support into a global static
> iommu: Add domain_alloc_identity()
> iommu/virtio: Move to domain_alloc_paging()
> iommu: Do not call domain_alloc() in iommu_sva_domain_alloc()
> iommu: Hide ops.domain_alloc behind CONFIG_FSL_PAMU
>
> drivers/iommu/iommu-sva.c | 15 ++-
> drivers/iommu/iommu.c | 16 +--
> drivers/iommu/virtio-iommu.c | 200
> +++++++++++++++++++++-------------- include/linux/iommu.h |
> 10 +- 4 files changed, 141 insertions(+), 100 deletions(-)
>
>
> base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b