RE: [PATCH 6/6] iommu: Make set_dev_pasid op support domain replacement

Tian, Kevin
2024-07-15T08:02:29Z

> From: Liu, Yi L <yi.l.liu@intel.com>
> Sent: Friday, June 28, 2024 4:56 PM
>
> The iommu core is going to support domain replacement for pasid, it needs
> to make the set_dev_pasid op support replacing domain and keep the old
> domain config in the failure case.
>
> Currently only the Intel iommu driver supports the latest set_dev_pasid
> op definition. ARM and AMD iommu driver do not support domain
> replacement
> for pasid yet, both drivers would fail the set_dev_pasid op to keep the
> old config if the input @old is non-NULL.

why splitting this from patch01?

>
> Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> ---
> drivers/iommu/amd/pasid.c | 3 +++
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 3 +++
> include/linux/iommu.h | 3 ++-
> 3 files changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/amd/pasid.c b/drivers/iommu/amd/pasid.c
> index 77bf5f5f947a..30e27bda3fac 100644
> --- a/drivers/iommu/amd/pasid.c
> +++ b/drivers/iommu/amd/pasid.c
> @@ -109,6 +109,9 @@ int iommu_sva_set_dev_pasid(struct iommu_domain
> *domain,
> unsigned long flags;
> int ret = -EINVAL;
>
> + if (old)
> + return -EOPNOTSUPP;
> +
> /* PASID zero is used for requests from the I/O device without PASID
> */
> if (!is_pasid_valid(dev_data, pasid))
> return ret;
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> index c058949749cb..a1e411c71efa 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> @@ -637,6 +637,9 @@ static int arm_smmu_sva_set_dev_pasid(struct
> iommu_domain *domain,
> int ret = 0;
> struct mm_struct *mm = domain->mm;
>
> + if (old)
> + return -EOPNOTSUPP;
> +
> if (mm_get_enqcmd_pasid(mm) != id)
> return -EINVAL;
>
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index a33f53aab61b..3259f77ff2e3 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -607,7 +607,8 @@ struct iommu_ops {
> * * EBUSY - device is attached to a domain and cannot be changed
> * * ENODEV - device specific errors, not able to be attached
> * * <others> - treated as ENODEV by the caller. Use is discouraged
> - * @set_dev_pasid: set an iommu domain to a pasid of device
> + * @set_dev_pasid: set or replace an iommu domain to a pasid of device.
> The pasid of
> + * the device should be left in the old config in error case.
> * @map_pages: map a physically contiguous set of pages of the same size
> to
> * an iommu domain.
> * @unmap_pages: unmap a number of pages of the same size from an
> iommu domain
> --
> 2.34.1