diff --git a/sys/kern/subr_intr.c b/sys/kern/subr_intr.c
--- a/sys/kern/subr_intr.c
+++ b/sys/kern/subr_intr.c
@@ -415,6 +415,18 @@
 	return (EINVAL);
 }
 
+/*
+ *  Lookup an interrupt source by number.
+ */
+interrupt_t *
+intrtab_lookup(u_int irq)
+{
+
+	if (irq >= intr_nirq)
+		return (NULL);
+	return (irq_sources[irq]);
+}
+
 /*
  *  Alloc unique interrupt number (resource handle) for interrupt source.
  *
diff --git a/sys/powerpc/include/intr.h b/sys/powerpc/include/intr.h
--- a/sys/powerpc/include/intr.h
+++ b/sys/powerpc/include/intr.h
@@ -28,6 +28,17 @@
 #ifndef	_MACHINE_INTR_MACHDEP_H_
 #define	_MACHINE_INTR_MACHDEP_H_
 
+/* FreeBSD standard interrupt controller interface */
+
+typedef struct powerpc_intr interrupt_t;
+
+extern interrupt_t *intrtab_lookup(u_int intr) __pure;
+
+extern struct intr_event *_intr2event(interrupt_t *intr);
+#define	intr2event(intr)	((intr) != NULL ? _intr2event(intr) : NULL)
+
+/* FreeBSD standard interrupt controller interface */
+
 #define	INTR_VECTORS	256
 
 #define	MAX_PICS		32
diff --git a/sys/powerpc/powerpc/intr_machdep.c b/sys/powerpc/powerpc/intr_machdep.c
--- a/sys/powerpc/powerpc/intr_machdep.c
+++ b/sys/powerpc/powerpc/intr_machdep.c
@@ -291,6 +291,28 @@
 	return (i);
 }
 
+interrupt_t *
+intrtab_lookup(u_int intr)
+{
+	struct powerpc_intr *i;
+	int vector;
+
+	for (vector = 0; vector < nvectors; vector++) {
+		i = powerpc_intrs[vector];
+		if (i != NULL && i->irq == intr)
+			return (i);
+	}
+
+	return (NULL);
+}
+
+struct intr_event *
+_intr2event(interrupt_t *intr)
+{
+
+	return (intr->event);
+}
+
 static int
 powerpc_map_irq(struct powerpc_intr *i)
 {
diff --git a/sys/sys/intr.h b/sys/sys/intr.h
--- a/sys/sys/intr.h
+++ b/sys/sys/intr.h
@@ -35,6 +35,17 @@
 
 #include <sys/systm.h>
 
+/* FreeBSD standard interrupt controller interface */
+
+typedef struct intr_irqsrc interrupt_t;
+
+extern interrupt_t *intrtab_lookup(u_int irq) __pure;
+
+#define	_intr2event(intr)	((intr)->isrc_event)
+#define	intr2event(intr)	((intr) != NULL ? _intr2event(intr) : NULL)
+
+/* FreeBSD standard interrupt controller interface */
+
 #define	INTR_IRQ_INVALID	0xFFFFFFFF
 
 enum intr_map_data_type {
diff --git a/sys/x86/include/intr.h b/sys/x86/include/intr.h
--- a/sys/x86/include/intr.h
+++ b/sys/x86/include/intr.h
@@ -30,6 +30,17 @@
 
 #ifdef _KERNEL
 
+/* FreeBSD standard interrupt controller interface */
+
+typedef struct intsrc interrupt_t;
+
+extern interrupt_t *intrtab_lookup(u_int irq) __pure;
+
+#define	_intr2event(intr)	((intr)->is_event)
+#define	intr2event(intr)	((intr) != NULL ? _intr2event(intr) : NULL)
+
+/* FreeBSD standard interrupt controller interface */
+
 /*
  * Values used in determining the allocation of IRQ values among
  * different types of I/O interrupts.  These values are used as
@@ -146,7 +157,6 @@
 int	intr_describe(struct intsrc *isrc, void *ih, const char *descr);
 void	intr_execute_handlers(struct intsrc *isrc, struct trapframe *frame);
 u_int	intr_next_cpu(int domain);
-struct intsrc *intr_lookup_source(int vector);
 int	intr_register_pic(struct pic *pic);
 int	intr_register_source(struct intsrc *isrc);
 int	intr_remove_handler(void *cookie);
diff --git a/sys/x86/isa/atpic.c b/sys/x86/isa/atpic.c
--- a/sys/x86/isa/atpic.c
+++ b/sys/x86/isa/atpic.c
@@ -228,7 +228,7 @@
 	if (ap != &atpics[MASTER])
 		return;
 	for (i = 0; i < NUM_ISA_IRQS; i++)
-		if (intr_lookup_source(i) != NULL)
+		if (intrtab_lookup(i) != NULL)
 			return;
 
 	/* Loop through all interrupt sources and add them. */
diff --git a/sys/x86/isa/clock.c b/sys/x86/isa/clock.c
--- a/sys/x86/isa/clock.c
+++ b/sys/x86/isa/clock.c
@@ -579,7 +579,7 @@
 	if (!(sc->port_res = bus_alloc_resource(dev, SYS_RES_IOPORT,
 	    &sc->port_rid, IO_TIMER1, IO_TIMER1 + 3, 4, RF_ACTIVE)))
 		device_printf(dev,"Warning: Couldn't map I/O.\n");
-	i8254_intsrc = intr_lookup_source(0);
+	i8254_intsrc = intrtab_lookup(0);
 	if (i8254_intsrc != NULL)
 		i8254_pending = i8254_intsrc->is_pic->pic_source_pending;
 	resource_int_value(device_get_name(dev), device_get_unit(dev),
diff --git a/sys/x86/x86/intr_machdep.c b/sys/x86/x86/intr_machdep.c
--- a/sys/x86/x86/intr_machdep.c
+++ b/sys/x86/x86/intr_machdep.c
@@ -245,11 +245,11 @@
 	return (0);
 }
 
-struct intsrc *
-intr_lookup_source(int vector)
+interrupt_t *
+intrtab_lookup(u_int vector)
 {
 
-	if (vector < 0 || vector >= num_io_irqs)
+	if (vector >= num_io_irqs)
 		return (NULL);
 	return (interrupt_sources[vector]);
 }
diff --git a/sys/x86/x86/local_apic.c b/sys/x86/x86/local_apic.c
--- a/sys/x86/x86/local_apic.c
+++ b/sys/x86/x86/local_apic.c
@@ -1296,8 +1296,7 @@
 	kmsan_mark(frame, sizeof(*frame), KMSAN_STATE_INITED);
 	trap_check_kstack();
 
-	isrc = intr_lookup_source(apic_idt_to_irq(PCPU_GET(apic_id),
-	    vector));
+	isrc = intrtab_lookup(apic_idt_to_irq(PCPU_GET(apic_id), vector));
 	intr_execute_handlers(isrc, frame);
 }
 
@@ -1741,7 +1740,7 @@
 			if (irq == IRQ_TIMER)
 				db_printf("lapic timer\n");
 			else if (irq < num_io_irqs) {
-				isrc = intr_lookup_source(irq);
+				isrc = intrtab_lookup(irq);
 				if (isrc == NULL || verbose == 0)
 					db_printf("IRQ %u\n", irq);
 				else
diff --git a/sys/x86/x86/msi.c b/sys/x86/x86/msi.c
--- a/sys/x86/x86/msi.c
+++ b/sys/x86/x86/msi.c
@@ -280,7 +280,7 @@
 	if (msi->msi_intsrc.is_handlers > 0)
 		apic_enable_vector(msi->msi_cpu, msi->msi_vector);
 	for (i = 1; i < msi->msi_count; i++) {
-		sib = (struct msi_intsrc *)intr_lookup_source(msi->msi_irqs[i]);
+		sib = (struct msi_intsrc *)intrtab_lookup(msi->msi_irqs[i]);
 		if (sib->msi_intsrc.is_handlers > 0)
 			apic_enable_vector(apic_id, vector + i);
 	}
@@ -293,7 +293,7 @@
 			    msi->msi_cpu, msi->msi_vector);
 		}
 		for (i = 1; i < msi->msi_count; i++) {
-			sib = (struct msi_intsrc *)intr_lookup_source(
+			sib = (struct msi_intsrc *)intrtab_lookup(
 			    msi->msi_irqs[i]);
 			sib->msi_cpu = apic_id;
 			sib->msi_vector = vector + i;
@@ -321,7 +321,7 @@
 		apic_disable_vector(old_id, old_vector);
 	apic_free_vector(old_id, old_vector, msi->msi_irq);
 	for (i = 1; i < msi->msi_count; i++) {
-		sib = (struct msi_intsrc *)intr_lookup_source(msi->msi_irqs[i]);
+		sib = (struct msi_intsrc *)intrtab_lookup(msi->msi_irqs[i]);
 		if (sib->msi_intsrc.is_handlers > 0)
 			apic_disable_vector(old_id, old_vector + i);
 		apic_free_vector(old_id, old_vector + i, msi->msi_irqs[i]);
@@ -420,7 +420,7 @@
 	/* Try to find 'count' free IRQs. */
 	cnt = 0;
 	for (i = first_msi_irq; i < first_msi_irq + num_msi_irqs; i++) {
-		msi = (struct msi_intsrc *)intr_lookup_source(i);
+		msi = (struct msi_intsrc *)intrtab_lookup(i);
 
 		/* End of allocated sources, so break. */
 		if (msi == NULL)
@@ -478,15 +478,15 @@
 		return (error);
 	}
 	for (i = 0; i < count; i++) {
-		msi = (struct msi_intsrc *)intr_lookup_source(irqs[i]);
+		msi = (struct msi_intsrc *)intrtab_lookup(irqs[i]);
 		msi->msi_remap_cookie = cookies[i];
 	}
 #endif
 
 	/* Assign IDT vectors and make these messages owned by 'dev'. */
-	fsrc = (struct msi_intsrc *)intr_lookup_source(irqs[0]);
+	fsrc = (struct msi_intsrc *)intrtab_lookup(irqs[0]);
 	for (i = 0; i < count; i++) {
-		msi = (struct msi_intsrc *)intr_lookup_source(irqs[i]);
+		msi = (struct msi_intsrc *)intrtab_lookup(irqs[i]);
 		msi->msi_cpu = cpu;
 		msi->msi_dev = dev;
 		msi->msi_vector = vector + i;
@@ -514,7 +514,7 @@
 	int i;
 
 	mtx_lock(&msi_lock);
-	first = (struct msi_intsrc *)intr_lookup_source(irqs[0]);
+	first = (struct msi_intsrc *)intrtab_lookup(irqs[0]);
 	if (first == NULL) {
 		mtx_unlock(&msi_lock);
 		return (ENOENT);
@@ -544,7 +544,7 @@
 
 	/* Clear all the extra messages in the group. */
 	for (i = 1; i < count; i++) {
-		msi = (struct msi_intsrc *)intr_lookup_source(irqs[i]);
+		msi = (struct msi_intsrc *)intrtab_lookup(irqs[i]);
 		KASSERT(msi->msi_first == first, ("message not in group"));
 		KASSERT(msi->msi_dev == first->msi_dev, ("owner mismatch"));
 #ifdef IOMMU
@@ -586,7 +586,7 @@
 #endif
 
 	mtx_lock(&msi_lock);
-	msi = (struct msi_intsrc *)intr_lookup_source(irq);
+	msi = (struct msi_intsrc *)intrtab_lookup(irq);
 	if (msi == NULL) {
 		mtx_unlock(&msi_lock);
 		return (ENOENT);
@@ -617,7 +617,7 @@
 		    i < first_msi_irq + num_msi_irqs; i++) {
 			if (i == msi->msi_irq)
 				continue;
-			msi1 = (struct msi_intsrc *)intr_lookup_source(i);
+			msi1 = (struct msi_intsrc *)intrtab_lookup(i);
 			if (!msi1->msi_msix && msi1->msi_first == msi) {
 				mtx_unlock(&msi_lock);
 				iommu_map_msi_intr(msi1->msi_dev,
@@ -670,7 +670,7 @@
 
 	/* Find a free IRQ. */
 	for (i = first_msi_irq; i < first_msi_irq + num_msi_irqs; i++) {
-		msi = (struct msi_intsrc *)intr_lookup_source(i);
+		msi = (struct msi_intsrc *)intrtab_lookup(i);
 
 		/* End of allocated sources, so break. */
 		if (msi == NULL)
@@ -745,7 +745,7 @@
 	struct msi_intsrc *msi;
 
 	mtx_lock(&msi_lock);
-	msi = (struct msi_intsrc *)intr_lookup_source(irq);
+	msi = (struct msi_intsrc *)intrtab_lookup(irq);
 	if (msi == NULL) {
 		mtx_unlock(&msi_lock);
 		return (ENOENT);
diff --git a/sys/x86/x86/nexus.c b/sys/x86/x86/nexus.c
--- a/sys/x86/x86/nexus.c
+++ b/sys/x86/x86/nexus.c
@@ -221,7 +221,7 @@
 	 * resource manager.
 	 */
 	for (irq = 0; irq < num_io_irqs; irq++)
-		if (intr_lookup_source(irq) != NULL)
+		if (intrtab_lookup(irq) != NULL)
 			if (rman_manage_region(&irq_rman, irq, irq) != 0)
 				panic("nexus_init_resources irq_rman add");
 
@@ -579,7 +579,7 @@
 	if (bus_get_domain(child, &domain) != 0)
 		domain = 0;
 
-	isrc = intr_lookup_source(rman_get_start(irq));
+	isrc = intrtab_lookup(rman_get_start(irq));
 	if (isrc == NULL)
 		return (EINVAL);
 	error = intr_add_handler(device_get_nameunit(child), isrc,
@@ -619,7 +619,7 @@
 {
 	struct intsrc *isrc;
 
-	isrc = intr_lookup_source(rman_get_start(irq));
+	isrc = intrtab_lookup(rman_get_start(irq));
 	if (isrc == NULL)
 		return (EINVAL);
 	return (intr_event_bind(isrc->is_event, cpu));
@@ -632,7 +632,7 @@
 {
 	struct intsrc *isrc;
 
-	isrc = intr_lookup_source(irq);
+	isrc = intrtab_lookup(irq);
 	if (isrc == NULL)
 		return (EINVAL);
 	return (intr_config_intr(isrc, trig, pol));
@@ -644,7 +644,7 @@
 {
 	struct intsrc *isrc;
 
-	isrc = intr_lookup_source(rman_get_start(irq));
+	isrc = intrtab_lookup(rman_get_start(irq));
 	if (isrc == NULL)
 		return (EINVAL);
 	return (intr_describe(isrc, cookie, descr));
diff --git a/sys/x86/xen/xen_arch_intr.c b/sys/x86/xen/xen_arch_intr.c
--- a/sys/x86/xen/xen_arch_intr.c
+++ b/sys/x86/xen/xen_arch_intr.c
@@ -349,7 +349,7 @@
 	vector = first_evtchn_irq + xen_intr_auto_vector_count;
 	xen_intr_auto_vector_count++;
 
-	KASSERT((intr_lookup_source(vector) == NULL),
+	KASSERT((intrtab_lookup(vector) == NULL),
 	    ("Trying to use an already allocated vector"));
 
 	mtx_unlock(&xen_intr_x86_lock);