diff --git a/arch/sim/include/irq.h b/arch/sim/include/irq.h
index 93397018d6..05942e5232 100644
--- a/arch/sim/include/irq.h
+++ b/arch/sim/include/irq.h
@@ -118,6 +118,7 @@ int up_cpu_index(void);
 irqstate_t up_irq_flags(void);
 irqstate_t up_irq_save(void);
 void up_irq_restore(irqstate_t flags);
+void up_irq_enable(void);
 
 /****************************************************************************
  * Inline functions
diff --git a/arch/sim/src/sim/posix/sim_hostirq.c b/arch/sim/src/sim/posix/sim_hostirq.c
index 8b6086c3cd..4bcc050859 100644
--- a/arch/sim/src/sim/posix/sim_hostirq.c
+++ b/arch/sim/src/sim/posix/sim_hostirq.c
@@ -118,6 +118,19 @@ void up_irq_restore(uint64_t flags)
   pthread_sigmask(SIG_SETMASK, &nmask.sigset, NULL);
 }
 
+/****************************************************************************
+ * Name: up_irq_enable
+ *
+ * Description:
+ *   Enable interrupts.
+ *
+ ****************************************************************************/
+
+void up_irq_enable(void)
+{
+  up_irq_restore(0);
+}
+
 /****************************************************************************
  * Name: up_irqinitialize
  ****************************************************************************/