Re: [PATCH v2 3/8] iommu: Add new flag to explictly request PASID capable domain

[Jason Gunthorpe <jgg@ziepe.ca>]

On Wed, Sep 11, 2024 at 10:19:06AM +0000, Vasant Hegde wrote:
> +static struct iommu_domain *__iommu_paging_domain_alloc_flags(struct device *dev,
> +						       unsigned int type,
> +						       unsigned int flags)
>  {
>  	const struct iommu_ops *ops;
>  	struct iommu_domain *domain;
> @@ -2059,9 +2067,24 @@ struct iommu_domain *iommu_paging_domain_alloc_flags(struct device *dev,
>  	if (!domain)
>  		return ERR_PTR(-ENOMEM);
>  
> -	iommu_domain_init(domain, IOMMU_DOMAIN_UNMANAGED, ops);
> +	iommu_domain_init(domain, type, ops);
>  	return domain;
>  }
> +
> +/**
> + * iommu_paging_domain_alloc_flags() - Allocate a paging domain
> + * @dev: device for which the domain is allocated
> + * @flags: Bitmap of iommufd_hwpt_alloc_flags
> + *
> + * Allocate a paging domain which will be managed by a kernel driver. Return
> + * allocated domain if successful, or a ERR pointer for failure.
> + */
> +struct iommu_domain *iommu_paging_domain_alloc_flags(struct device *dev,
> +						     unsigned int flags)
> +{
> +	return __iommu_paging_domain_alloc_flags(dev,
> +					 IOMMU_DOMAIN_UNMANAGED, flags);

Can we get rid of the type parameter here? Like this:

       if (req_type & __IOMMU_DOMAIN_PAGING) {
               dom =  __iommu_paging_domain_alloc_flags(dev,
                               dev->iommu->max_pasids ?
			       IOMMU_HWPT_ALLOC_PASID : 0);
		if (IS_ERR(dom))
		   return dom;
		dom->type = req_type;
       }

Maybe at the end of the series, I guess you want AMD to not have a
bisection issue?

I think this looks OK otherwise

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

Jason