On Thu, May 08, 2025 at 08:02:38PM -0700, Nicolin Chen wrote:
An impl driver might want to allocate its own type of vIOMMU object or the standard IOMMU_VIOMMU_TYPE_ARM_SMMUV3 by setting up its own SW/HW bits, as the tegra241-cmdqv driver will add IOMMU_VIOMMU_TYPE_TEGRA241_CMDQV.
Add a vsmmu_alloc op and prioritize it in arm_vsmmu_alloc().
Reviewed-by: Pranjal Shrivastava praan@google.com Signed-off-by: Nicolin Chen nicolinc@nvidia.com
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 6 ++++++ .../iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c | 17 +++++++++++------ 2 files changed, 17 insertions(+), 6 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h index 6b8f0d20dac3..a5835af72417 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h @@ -16,6 +16,7 @@ #include <linux/sizes.h> struct arm_smmu_device; +struct arm_smmu_domain; /* MMIO registers */ #define ARM_SMMU_IDR0 0x0 @@ -720,6 +721,11 @@ struct arm_smmu_impl_ops { int (*init_structures)(struct arm_smmu_device *smmu); struct arm_smmu_cmdq *(*get_secondary_cmdq)( struct arm_smmu_device *smmu, struct arm_smmu_cmdq_ent *ent);
- struct arm_vsmmu *(*vsmmu_alloc)(
struct arm_smmu_device *smmu,struct arm_smmu_domain *smmu_domain, struct iommufd_ctx *ictx,unsigned int viommu_type,const struct iommu_user_data *user_data);};
I think you should put the supported viommu type here in the ops struct and match it here:
- /* Prioritize the impl that may support IOMMU_VIOMMU_TYPE_ARM_SMMUV3 */
- if (master->smmu->impl_ops && master->smmu->impl_ops->vsmmu_alloc)
vsmmu = master->smmu->impl_ops->vsmmu_alloc(master->smmu, s2_parent, ictx, viommu_type, user_data);
instead of the EOPNOTSUPP dance. Either the impl_ops supports the requested viommu as an extension or we are running in the normal mode?
Is there a reason to allocate a different viommu if the userspace does not enable the implementation specific features?
Jason