Re: [PATCH v4 09/12] iommu/amd: Enhance amd_iommu_domain_alloc_user()

[Jason Gunthorpe <jgg@ziepe.ca>]

On Wed, Oct 23, 2024 at 10:42:04AM +0000, Vasant Hegde wrote:
> Previous patch enhanced core layer to check device PASID capability and
> pass right flags to ops->domain_alloc_user().
> 
> Enhance amd_iommu_domain_alloc_user() to allocate domain with
> appropriate page table based on flags parameter.
>   - If flags is empty then allocate domain with default page table type.
>     This will eventually replace ops->domain_alloc().
>     For UNMANAGED domain, core will call this interface with flags=0. So
>     AMD driver will continue to allocate V1 page table.
> 
>   - If IOMMU_HWPT_ALLOC_PASID flags is passed then allocate domain with v2
>     page table.
> 
> Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
> ---
>  drivers/iommu/amd/iommu.c | 18 +++++++++++++++++-
>  1 file changed, 17 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
> index cb6a72564c23..cdc93c794eff 100644
> --- a/drivers/iommu/amd/iommu.c
> +++ b/drivers/iommu/amd/iommu.c
> @@ -2403,10 +2403,26 @@ amd_iommu_domain_alloc_user(struct device *dev, u32 flags,
>  
>  {
>  	unsigned int type = IOMMU_DOMAIN_UNMANAGED;
> +	const u32 supported_flags = IOMMU_HWPT_ALLOC_DIRTY_TRACKING |
> +						IOMMU_HWPT_ALLOC_PASID;
>  
> -	if ((flags & ~IOMMU_HWPT_ALLOC_DIRTY_TRACKING) || parent || user_data)
> +	if ((flags & ~supported_flags) || parent || user_data)
>  		return ERR_PTR(-EOPNOTSUPP);
>  
> +	/* Allocate domain with default page table */
> +	if (!flags) {
> +		return do_iommu_domain_alloc(IOMMU_DOMAIN_DMA,
> +					     dev, 0, amd_iommu_pgtable);
> +	}
> +
> +	/* Allocate domain with v2 page table if IOMMU supports PASID. */
> +	if (flags & IOMMU_HWPT_ALLOC_PASID) {
> +		if (!amd_iommu_pasid_supported())
> +			return ERR_PTR(-EOPNOTSUPP);
> +
> +		return do_iommu_domain_alloc(type, dev, flags, AMD_IOMMU_V2);
> +	}
> +
>  	return do_iommu_domain_alloc(type, dev, flags, AMD_IOMMU_V1);

This should be more specific about what the dirty_tracking
configuration needs:

	if (flags & IOMMU_HWPT_ALLOC_DIRTY_TRACKING) {
		if (!amd_iommu_hd_support(iommu) ||
		    (flags & IOMMU_HWPT_ALLOC_PASID))
			return ERR_PTR(-EOPNOTSUPP);
		return do_iommu_domain_alloc(type, dev, flags, AMD_IOMMU_V1);
	}

	if (flags & IOMMU_HWPT_ALLOC_PASID) {
		if (!amd_iommu_pasid_supported())
			return ERR_PTR(-EOPNOTSUPP);
		return do_iommu_domain_alloc(type, dev, flags, AMD_IOMMU_V2);
	}

	/* If nothing specific is required use the kernel commandline default */
	return do_iommu_domain_alloc(IOMMU_DOMAIN_DMA, dev, 0,
				     amd_iommu_pgtable);

Jason