2 files changed, 26 insertions, 0 deletions

diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index bc2f5719dace..188eced6813e 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -222,6 +222,7 @@ struct irq_domain *irq_domain_add_legacy(struct device_node *of_node,
                                          void *host_data);
 extern struct irq_domain *irq_find_matching_fwspec(struct irq_fwspec *fwspec,
                                                    enum irq_domain_bus_token bus_token);
+extern bool irq_domain_check_msi_remap(void);
 extern void irq_set_default_host(struct irq_domain *host);
 extern int irq_domain_alloc_descs(int virq, unsigned int nr_irqs,
                                   irq_hw_number_t hwirq, int node,
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 876e13172dc8..80c4f9312187 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -278,6 +278,31 @@ struct irq_domain *irq_find_matching_fwspec(struct irq_fwspec *fwspec,
 EXPORT_SYMBOL_GPL(irq_find_matching_fwspec);
 
 /**
+ * irq_domain_check_msi_remap - Check whether all MSI irq domains implement
+ * IRQ remapping
+ *
+ * Return: false if any MSI irq domain does not support IRQ remapping,
+ * true otherwise (including if there is no MSI irq domain)
+ */
+bool irq_domain_check_msi_remap(void)
+{
+        struct irq_domain *h;
+        bool ret = true;
+
+        mutex_lock(&irq_domain_mutex);
+        list_for_each_entry(h, &irq_domain_list, link) {
+                if (irq_domain_is_msi(h) &&
+                    !irq_domain_hierarchical_is_msi_remap(h)) {
+                        ret = false;
+                        break;
+                }
+        }
+        mutex_unlock(&irq_domain_mutex);
+        return ret;
+}
+EXPORT_SYMBOL_GPL(irq_domain_check_msi_remap);
+
+/**
  * irq_set_default_host() - Set a "default" irq domain
  * @domain: default domain pointer
  *