diff --git a/sys/x86/include/intr_machdep.h b/sys/x86/include/intr_machdep.h
--- a/sys/x86/include/intr_machdep.h
+++ b/sys/x86/include/intr_machdep.h
@@ -138,12 +138,12 @@
 #ifdef SMP
 void	intr_add_cpu(u_int cpu);
 #endif
-int	intr_add_handler(const char *name, int vector, driver_filter_t filter,
-    driver_intr_t handler, void *arg, enum intr_type flags, void **cookiep,
-    int domain);
-int	intr_config_intr(int vector, enum intr_trigger trig,
+int	intr_add_handler(struct intsrc *isrc, const char *name,
+     driver_filter_t filter, driver_intr_t handler, void *arg,
+     enum intr_type flags, void **cookiep, int domain);
+int	intr_config_intr(struct intsrc *isrc, enum intr_trigger trig,
     enum intr_polarity pol);
-int	intr_describe(u_int vector, void *ih, const char *descr);
+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);
diff --git a/sys/x86/include/xen/arch-intr.h b/sys/x86/include/xen/arch-intr.h
--- a/sys/x86/include/xen/arch-intr.h
+++ b/sys/x86/include/xen/arch-intr.h
@@ -67,7 +67,7 @@
     struct xenisrc *isrc, void **cookiep)
 {
 
-	return (intr_add_handler(name, isrc->xi_arch.vector, filter, handler,
+	return (intr_add_handler(&isrc->xi_arch.intsrc, name, filter, handler,
 	    arg, flags, cookiep, 0));
 }
 
@@ -75,7 +75,7 @@
 xen_arch_intr_describe(struct xenisrc *isrc, void *cookie, const char *descr)
 {
 
-	return (intr_describe(isrc->xi_arch.vector, cookie, descr));
+	return (intr_describe(&isrc->xi_arch.intsrc, cookie, descr));
 }
 
 static inline int
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
@@ -255,16 +255,12 @@
 }
 
 int
-intr_add_handler(const char *name, int vector, driver_filter_t filter,
+intr_add_handler(struct intsrc *isrc, const char *name, driver_filter_t filter,
     driver_intr_t handler, void *arg, enum intr_type flags, void **cookiep,
     int domain)
 {
-	struct intsrc *isrc;
 	int error;
 
-	isrc = intr_lookup_source(vector);
-	if (isrc == NULL)
-		return (EINVAL);
 	error = intr_event_add_handler(isrc->is_event, name, filter, handler,
 	    arg, intr_priority(flags), flags, cookiep);
 	if (error == 0) {
@@ -303,13 +299,10 @@
 }
 
 int
-intr_config_intr(int vector, enum intr_trigger trig, enum intr_polarity pol)
+intr_config_intr(struct intsrc *isrc, enum intr_trigger trig,
+    enum intr_polarity pol)
 {
-	struct intsrc *isrc;
 
-	isrc = intr_lookup_source(vector);
-	if (isrc == NULL)
-		return (EINVAL);
 	return (isrc->is_pic->pic_config_intr(isrc, trig, pol));
 }
 
@@ -513,14 +506,10 @@
 
 /* Add a description to an active interrupt handler. */
 int
-intr_describe(u_int vector, void *ih, const char *descr)
+intr_describe(struct intsrc *isrc, void *ih, const char *descr)
 {
-	struct intsrc *isrc;
 	int error;
 
-	isrc = intr_lookup_source(vector);
-	if (isrc == NULL)
-		return (EINVAL);
 	error = intr_event_describe_handler(isrc->is_event, ih, descr);
 	if (error)
 		return (error);
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
@@ -457,6 +457,7 @@
 		 void *arg, void **cookiep)
 {
 	int		error, domain;
+	struct intsrc	*isrc;
 
 	/* somebody tried to setup an irq that failed to allocate! */
 	if (irq == NULL)
@@ -475,8 +476,11 @@
 	if (bus_get_domain(child, &domain) != 0)
 		domain = 0;
 
-	error = intr_add_handler(device_get_nameunit(child),
-	    rman_get_start(irq), filter, ihand, arg, flags, cookiep, domain);
+	isrc = intr_lookup_source(rman_get_start(irq));
+	if (isrc == NULL)
+		return (EINVAL);
+	error = intr_add_handler(isrc, device_get_nameunit(child),
+	    filter, ihand, arg, flags, cookiep, domain);
 	if (error == 0)
 		rman_set_irq_cookie(irq, *cookiep);
 
@@ -523,15 +527,24 @@
 nexus_config_intr(device_t dev, int irq, enum intr_trigger trig,
     enum intr_polarity pol)
 {
-	return (intr_config_intr(irq, trig, pol));
+	struct intsrc *isrc;
+
+	isrc = intr_lookup_source(irq);
+	if (isrc == NULL)
+		return (EINVAL);
+	return (intr_config_intr(isrc, trig, pol));
 }
 
 static int
 nexus_describe_intr(device_t dev, device_t child, struct resource *irq,
     void *cookie, const char *descr)
 {
+	struct intsrc *isrc;
 
-	return (intr_describe(rman_get_start(irq), cookie, descr));
+	isrc = intr_lookup_source(rman_get_start(irq));
+	if (isrc == NULL)
+		return (EINVAL);
+	return (intr_describe(isrc, cookie, descr));
 }
 
 static struct resource_list *