[PATCH v4 09/12] iommu/arm-smmu-v3: Support IOMMU_DOMAIN_NESTED

[Zhangfei Gao]

On Mon, 4 Nov 2024 at 17:19, Jason Gunthorpe <jgg at nvidia.com> wrote:
>
> On Thu, Oct 31, 2024 at 02:21:11PM +0800, Zhangfei Gao wrote:
>
> > > +static struct iommu_domain *
> > > +arm_vsmmu_alloc_domain_nested(struct iommufd_viommu *viommu, u32 flags,
> > > +                             const struct iommu_user_data *user_data)
> > > +{
> > > +       struct arm_vsmmu *vsmmu = container_of(viommu, struct arm_vsmmu, core);
> > > +       struct arm_smmu_nested_domain *nested_domain;
> > > +       struct iommu_hwpt_arm_smmuv3 arg;
> > > +       int ret;
> > > +
> > > +       if (flags)
> > > +               return ERR_PTR(-EOPNOTSUPP);
> >
> > This check fails when using user page fault, with flags =
> > IOMMU_HWPT_FAULT_ID_VALID (4)
> > Strange, the check is not exist in last version?
> >
> > iommufd_viommu_alloc_hwpt_nested ->
> > viommu->ops->alloc_domain_nested(viommu, flags, user_data) ->
> > arm_vsmmu_alloc_domain_nested
>
> It should permit IOMMU_HWPT_FAULT_ID_VALID, I'll add this hunk:
>
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c
> @@ -178,12 +178,18 @@ arm_vsmmu_alloc_domain_nested(struct iommufd_viommu *viommu, u32 flags,
>                               const struct iommu_user_data *user_data)
>  {
>         struct arm_vsmmu *vsmmu = container_of(viommu, struct arm_vsmmu, core);
> +       const u32 SUPPORTED_FLAGS = IOMMU_HWPT_FAULT_ID_VALID;
>         struct arm_smmu_nested_domain *nested_domain;
>         struct iommu_hwpt_arm_smmuv3 arg;
>         bool enable_ats = false;
>         int ret;
>
> -       if (flags)
> +       /*
> +        * Faults delivered to the nested domain are faults that originated by
> +        * the S1 in the domain. The core code will match all PASIDs when
> +        * delivering the fault due to user_pasid_table
> +        */
> +       if (flags & ~SUPPORTED_FLAGS)
>                 return ERR_PTR(-EOPNOTSUPP);

Thanks Jason, this works