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

Jason Gunthorpe
2025-02-07T14:46:10Z

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

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
--
2.43.0