Re: [PATCH v2 5/5] iommu/vt-d: Add nested domain support

[Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx>]

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