On 3/13/23 5:11 PM, Liu, Jingqi wrote:

...

+struct iommu_domain *intel_nested_domain_alloc(struct iommu_domain *s2_domain,

• 			       const void *user_data)
  

+{

• const struct iommu_hwpt_intel_vtd *vtd = user_data;
• struct dmar_domain *domain;

Would it be better to add the following check ?

if (WARN_ON(!user_data)) return NULL;

The iommufd has already done the sanity check. Considering that this callback is only for iommufd purpose, the individual driver has no need to check it.

Best regards, baolu