Re: [PATCH 01/12] iommu: Add new iommu op to create domains owned by userspace

[Jason Gunthorpe <jgg@nvidia.com>]

On Thu, Mar 09, 2023 at 12:08:59AM -0800, Yi Liu wrote:
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index 3ef84ee359d2..a269bc62a31c 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -229,6 +229,7 @@ struct iommu_iotlb_gather {
>   *           after use. Return the data buffer if success, or ERR_PTR on
>   *           failure.
>   * @domain_alloc: allocate iommu domain
> + * @domain_alloc_user: allocate user iommu domain
>   * @probe_device: Add device to iommu driver handling
>   * @release_device: Remove device from iommu driver handling
>   * @probe_finalize: Do final setup work after the device is added to an IOMMU
> @@ -266,6 +267,9 @@ struct iommu_ops {
>  
>  	/* Domain allocation and freeing by the iommu driver */
>  	struct iommu_domain *(*domain_alloc)(unsigned iommu_domain_type);
> +	struct iommu_domain *(*domain_alloc_user)(struct device *dev,
> +						  struct iommu_domain *parent,
> +						  const void *user_data);

Since the kernel does the copy from user and manages the zero fill
compat maybe this user_data have a union like Robin suggested.

But yes, this is the idea.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason