iommufd: Check the domain owner of the parent before creating a nesting domain

This check was missed, before we can pass a struct iommu_domain to a
driver callback we need to validate that the domain was created by that
driver.

Fixes: bd529db ("iommufd: Add a nested HW pagetable object")
Link: https://patch.msgid.link/r/0-v1-c8770519edde+1a-iommufd_nesting_ops_jgg@nvidia.com
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

Author: jgunthorpe

drivers/iommu/iommufd/hw_pagetable.c

@@ -225,7 +225,8 @@ iommufd_hwpt_nested_alloc(struct iommufd_ctx *ictx,
 	if ((flags & ~IOMMU_HWPT_FAULT_ID_VALID) ||
 	    !user_data->len || !ops->domain_alloc_user)
 		return ERR_PTR(-EOPNOTSUPP);
-	if (parent->auto_domain || !parent->nest_parent)
+	if (parent->auto_domain || !parent->nest_parent ||
+	    parent->common.domain->owner != ops)
 		return ERR_PTR(-EINVAL);
 
 	hwpt_nested = __iommufd_object_alloc(