Re: [PATCH 04/12] iommufd: Pass parent hwpt and user_data to iommufd_hw_pagetable_alloc()

On Fri, Mar 10, 2023 at 10:10:56AM +0800, Baolu Lu wrote:

...

@@ -54,14 +58,20 @@ int iommufd_hw_pagetable_enforce_cc(struct iommufd_hw_pagetable *hwpt) */ struct iommufd_hw_pagetable * iommufd_hw_pagetable_alloc(struct iommufd_ctx *ictx, struct iommufd_ioas *ioas,

• 	   struct iommufd_device *idev, bool immediate_attach)
  

• 	   struct iommufd_device *idev,
  

• 	   struct iommufd_hw_pagetable *parent,
  

• 	   void *user_data, bool immediate_attach)
  

  { const struct iommu_ops *ops = dev_iommu_ops(idev->dev);
• struct iommu_domain *parent_domain = NULL; struct iommufd_hw_pagetable *hwpt; int rc; lockdep_assert_held(&ioas->mutex);
• if (parent && !ops->domain_alloc_user)

• return ERR_PTR(-EOPNOTSUPP);
  

My understanding here is that we are checking whether domain_alloc_user is required. It seems that as long as the caller inputs a valid user_data or parent, domain_alloc_user is required. If so,

if ((user_data || parent) && !ops->domain_alloc_user) return ERR_PTR(-EOPNOTSUPP);

Yes

Jason