Index: kernel/arch/mips32/src/mach/msim/msim.c
===================================================================
--- kernel/arch/mips32/src/mach/msim/msim.c	(revision e064102b80157d447412b71a989a3c26c6447a20)
+++ kernel/arch/mips32/src/mach/msim/msim.c	(revision 3e828ea40985ce126affd5d7faa6ba679802b4db)
@@ -41,4 +41,5 @@
 #include <genarch/drivers/dsrln/dsrlnout.h>
 #include <genarch/srln/srln.h>
+#include <stdbool.h>
 
 static void msim_init(void);
@@ -60,6 +61,28 @@
 };
 
+static void msim_irq_handler(unsigned int i)
+{
+	irq_t *irq = irq_dispatch_and_lock(i);
+	if (irq) {
+		irq->handler(irq);
+		irq_spinlock_unlock(&irq->lock, false);
+	} else {
+#ifdef CONFIG_DEBUG
+		log(LF_ARCH, LVL_DEBUG, "cpu%u: spurious IRQ (irq=%u)",
+		    CPU->id, i);
+#endif
+	}
+}
+
 void msim_init(void)
 {
+	irq_init(HW_INTERRUPTS, HW_INTERRUPTS);
+
+	int_handler[INT_HW0] = msim_irq_handler;
+	int_handler[INT_HW1] = msim_irq_handler;
+	int_handler[INT_HW2] = msim_irq_handler;
+	int_handler[INT_HW3] = msim_irq_handler;
+	int_handler[INT_HW4] = msim_irq_handler;
+
 	dorder_init();
 	cp0_unmask_int(MSIM_DDISK_IRQ);