void (*iommu_data_release)(void *iommu_data);
        char *name;
        int id;
+       struct iommu_domain *default_domain;
 };
 
 struct iommu_device {
 #define to_iommu_group(_kobj)          \
        container_of(_kobj, struct iommu_group, kobj)
 
+static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,
+                                                unsigned type);
+
 static ssize_t iommu_group_attr_show(struct kobject *kobj,
                                     struct attribute *__attr, char *buf)
 {
        ida_remove(&iommu_group_ida, group->id);
        mutex_unlock(&iommu_group_mutex);
 
+       if (group->default_domain)
+               iommu_domain_free(group->default_domain);
+
        kfree(group->name);
        kfree(group);
 }
                return group;
 
        /* No shared group found, allocate new */
-       return iommu_group_alloc();
+       group = iommu_group_alloc();
+       if (group) {
+               /*
+                * Try to allocate a default domain - needs support from the
+                * IOMMU driver.
+                */
+               group->default_domain = __iommu_domain_alloc(pdev->dev.bus,
+                                                            IOMMU_DOMAIN_DMA);
+       }
+
+       return group;
 }
 
 /**
 }
 EXPORT_SYMBOL_GPL(iommu_set_fault_handler);
 
-struct iommu_domain *iommu_domain_alloc(struct bus_type *bus)
+static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,
+                                                unsigned type)
 {
        struct iommu_domain *domain;
 
        if (bus == NULL || bus->iommu_ops == NULL)
                return NULL;
 
-       domain = bus->iommu_ops->domain_alloc(IOMMU_DOMAIN_UNMANAGED);
+       domain = bus->iommu_ops->domain_alloc(type);
        if (!domain)
                return NULL;
 
        domain->ops  = bus->iommu_ops;
-       domain->type = IOMMU_DOMAIN_UNMANAGED;
+       domain->type = type;
 
        return domain;
 }
+
+struct iommu_domain *iommu_domain_alloc(struct bus_type *bus)
+{
+       return __iommu_domain_alloc(bus, IOMMU_DOMAIN_UNMANAGED);
+}
 EXPORT_SYMBOL_GPL(iommu_domain_alloc);
 
 void iommu_domain_free(struct iommu_domain *domain)