Re: [PATCH v2 6/8] iommu/amd: Enhance domain_alloc_user() to allocate PASID capable domain

[Jason Gunthorpe <jgg@ziepe.ca>]

On Wed, Sep 11, 2024 at 10:19:09AM +0000, Vasant Hegde wrote:
> Allocate domain with v2 page table if IOMMU_HWPT_ALLOC_PASID flag is
> passed to ops->domain_alloc_user().
> 
> Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
> ---
>  drivers/iommu/amd/iommu.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
> index cfeb3202ceee..1c9e539f15a7 100644
> --- a/drivers/iommu/amd/iommu.c
> +++ b/drivers/iommu/amd/iommu.c
> @@ -2401,12 +2401,23 @@ amd_iommu_domain_alloc_user(struct device *dev, u32 flags,
>  			    const struct iommu_user_data *user_data)
>  
>  {
> +	struct iommu_dev_data *dev_data = dev_iommu_priv_get(dev);
>  	unsigned int type = IOMMU_DOMAIN_UNMANAGED;
> +	int pgtable = AMD_IOMMU_V1;
>  
>  	if ((flags & ~IOMMU_HWPT_ALLOC_DIRTY_TRACKING) || parent || user_data)
>  		return ERR_PTR(-EOPNOTSUPP);
>  
> -	return do_iommu_domain_alloc(type, dev, flags, AMD_IOMMU_V1);
> +	/* Allocate v2 page table if IOMMU and device supports PASID. */
> +	if (flags & IOMMU_HWPT_ALLOC_PASID) {
> +		if (!amd_iommu_pasid_supported() ||
> +		    !pdev_pasid_supported(dev_data))

The test to disable v2 support uses:

	if (!check_feature(FEATURE_GIOSUP) ||
	    !check_feature(FEATURE_GT)) {

But this doesn't check FEATURE_GIOSUP, just GT? Is it OK?

Jason