[PATCH v8 20/24] iommu: Require a default_domain for all iommu drivers

[Dmitry Baryshkov]

On Tue, 3 Oct 2023 at 02:00, Jason Gunthorpe <jgg at nvidia.com> wrote:
>
> On Tue, Oct 03, 2023 at 12:21:59AM +0300, Dmitry Baryshkov wrote:
> > On Wed, 13 Sept 2023 at 16:45, Jason Gunthorpe <jgg at nvidia.com> wrote:
> > >
> > > At this point every iommu driver will cause a default_domain to be
> > > selected, so we can finally remove this gap from the core code.
> > >
> > > The following table explains what each driver supports and what the
> > > resulting default_domain will be:
> > >
> > >                                         ops->defaut_domain
> > >                     IDENTITY   DMA  PLATFORM    v      ARM32          dma-iommu  ARCH
> > > amd/iommu.c             Y       Y                       N/A             either
> > > apple-dart.c            Y       Y                       N/A             either
> > > arm-smmu.c              Y       Y                       IDENTITY        either
> > > qcom_iommu.c            G       Y                       IDENTITY        either
> > > arm-smmu-v3.c           Y       Y                       N/A             either
> > > exynos-iommu.c          G       Y                       IDENTITY        either
> > > fsl_pamu_domain.c                       Y       Y       N/A             N/A     PLATFORM
> > > intel/iommu.c           Y       Y                       N/A             either
> > > ipmmu-vmsa.c            G       Y                       IDENTITY        either
> > > msm_iommu.c             G                               IDENTITY        N/A
> >
> > Unfortunately this patch breaks msm_iommu platforms. This driver
> > doesn't select ARM_DMA_USE_IOMMU, so iommu_get_default_domain_type()
> > returns 0, bus_iommu_probe() fails with -ENODEV.
> > If I make MSM_IOMMU select ARM_DMA_USE_IOMMU, then GPU probing fails
> > with -EBUSY.
>
> Oh, OK.
>
> Does this fix it?

It indeed fixes the issue, so could you please post it, adding:
Tested-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>

> diff --git a/drivers/iommu/msm_iommu.c b/drivers/iommu/msm_iommu.c
> index cdc7b730192a35..f7ef081c33dcb2 100644
> --- a/drivers/iommu/msm_iommu.c
> +++ b/drivers/iommu/msm_iommu.c
> @@ -685,10 +685,16 @@ irqreturn_t msm_iommu_fault_handler(int irq, void *dev_id)
>         return 0;
>  }
>
> +static int msm_iommu_def_domain_type(struct device *dev)
> +{
> +       return IOMMU_DOMAIN_IDENTITY;
> +}
> +
>  static struct iommu_ops msm_iommu_ops = {
>         .identity_domain = &msm_iommu_identity_domain,
>         .domain_alloc_paging = msm_iommu_domain_alloc_paging,
>         .probe_device = msm_iommu_probe_device,
> +       .def_domain_type = msm_iommu_def_domain_type,
>         .device_group = generic_device_group,
>         .pgsize_bitmap = MSM_IOMMU_PGSIZES,
>         .of_xlate = qcom_iommu_of_xlate,

-- 
With best wishes
Dmitry