On Sat, Jun 10, 2023 at 05:08:31PM +0800, Baolu Lu wrote:

quoted

@@ -1992,8 +1993,13 @@ static struct iommu_domain *__iommu_domain_alloc(const struct iommu_ops *ops,
  	if (alloc_type == IOMMU_DOMAIN_IDENTITY && ops->identity_domain)
  		return ops->identity_domain;
+	else if (type & __IOMMU_DOMAIN_PAGING) {
+		domain = ops->domain_alloc_paging(dev);

This might be problematic because not all IOMMU drivers implement this
callback now. In the missing cases, the code will always result in a
null pointer reference issue?

Ah, thank you that is a rebasing error :(

quoted

  struct iommu_domain *iommu_domain_alloc(const struct bus_type *bus)
  {
  	if (bus == NULL || bus->iommu_ops == NULL)
  		return NULL;
-	return __iommu_domain_alloc(bus->iommu_ops, IOMMU_DOMAIN_UNMANAGED);
+	return __iommu_domain_alloc(bus->iommu_ops, NULL,
+				    IOMMU_DOMAIN_UNMANAGED);

Suppose that iommu_domain_alloc() is always called from device drivers
where device pointer is always available. Is it possible to convert it
to a real device pointer?

Yes, Robin has a series for that

Jason