Index: sys/amd64/include/intr_machdep.h
===================================================================
--- sys/amd64/include/intr_machdep.h
+++ sys/amd64/include/intr_machdep.h
@@ -143,6 +143,9 @@
 	register_t	__padding;	/* pad to 16 bytes */
 };
 
+#ifdef SMP
+extern cpuset_t intr_cpus;
+#endif
 extern struct mtx icu_lock;
 extern int elcr_found;
 
Index: sys/dev/acpica/acpi.c
===================================================================
--- sys/dev/acpica/acpi.c
+++ sys/dev/acpica/acpi.c
@@ -209,6 +209,7 @@
     DEVMETHOD(bus_setup_intr,		bus_generic_setup_intr),
     DEVMETHOD(bus_teardown_intr,	bus_generic_teardown_intr),
     DEVMETHOD(bus_hint_device_unit,	acpi_hint_device_unit),
+    DEVMETHOD(bus_get_cpus,		acpi_get_cpus),
     DEVMETHOD(bus_get_domain,		acpi_get_domain),
 
     /* ACPI bus */
@@ -1072,6 +1073,28 @@
     }
 }
 
+int
+acpi_get_cpus(device_t dev, device_t child, enum cpu_sets op, cpuset_t *cpuset, int size)
+{
+	int rc, d, error;
+
+	if ((rc = acpi_get_domain(dev, child, &d)) != 0)
+		return (rc);
+
+	switch (op) {
+	case LOCAL_CPUS:
+		*cpuset = cpuset_domain[d];
+		return (0);
+	case INTR_CPUS:
+		if ((error = bus_generic_get_cpus(dev, child, op, cpuset, size)))
+			return (error);
+		CPU_AND(cpuset, &cpuset_domain[d]);
+		return (0);
+	default:
+		return (bus_generic_get_cpus(dev, child, op, cpuset, size));
+	}
+}
+
 /*
  * Fetch the VM domain for the given device 'dev'.
  *
@@ -1085,9 +1108,10 @@
 	ACPI_HANDLE h;
 	int d, pxm;
 
-	h = acpi_get_handle(dev);
-	if ((h != NULL) &&
-	    ACPI_SUCCESS(acpi_GetInteger(h, "_PXM", &pxm))) {
+	if ((h = acpi_get_handle(dev)) == NULL)
+		return (ENOENT);
+
+	if (ACPI_SUCCESS(acpi_GetInteger(h, "_PXM", &pxm))) {
 		d = acpi_map_pxm_to_vm_domainid(pxm);
 		if (d < 0)
 			return (-1);
@@ -1095,7 +1119,6 @@
 		return (1);
 	}
 #endif
-
 	return (0);
 }
 
Index: sys/dev/acpica/acpi_pci.c
===================================================================
--- sys/dev/acpica/acpi_pci.c
+++ sys/dev/acpica/acpi_pci.c
@@ -98,6 +98,7 @@
 	DEVMETHOD(bus_read_ivar,	acpi_pci_read_ivar),
 	DEVMETHOD(bus_write_ivar,	acpi_pci_write_ivar),
 	DEVMETHOD(bus_child_location_str, acpi_pci_child_location_str_method),
+	DEVMETHOD(bus_get_cpus,		acpi_get_cpus),
 	DEVMETHOD(bus_get_dma_tag,	acpi_pci_get_dma_tag),
 	DEVMETHOD(bus_get_domain,	acpi_get_domain),
 
Index: sys/dev/acpica/acpivar.h
===================================================================
--- sys/dev/acpica/acpivar.h
+++ sys/dev/acpica/acpivar.h
@@ -503,6 +503,9 @@
 #if MAXMEMDOM > 1
 extern	int acpi_map_pxm_to_vm_domainid(int pxm);
 #endif
+
+extern int	acpi_get_cpus(device_t dev, device_t child, enum cpu_sets op,
+      cpuset_t *cpuset, int size);
 extern	int acpi_get_domain(device_t dev, device_t child, int *domain);
 extern	int acpi_parse_pxm(device_t dev, int *domain);
 
Index: sys/kern/bus_if.m
===================================================================
--- sys/kern/bus_if.m
+++ sys/kern/bus_if.m
@@ -707,3 +707,21 @@
 	device_t	_child;
 	int		*_domain;
 } DEFAULT bus_generic_get_domain;
+
+/**
+ * @brief Request a set of CPUs
+ *
+ * @param _dev		the bus device
+ * @param _child	the child device
+ * @param _op		type of CPUs to request
+ * @param _cpuset	a pointer to a cpuset to receive the requested set of CPUs
+ * @param _size		size of cpuset
+ *
+ */
+METHOD int get_cpus {
+	device_t	_dev;
+	device_t	_child;
+	enum cpu_sets	_op;
+	cpuset_t	*_cpuset;
+	int		_size;
+} DEFAULT bus_generic_get_cpus;
Index: sys/kern/subr_bus.c
===================================================================
--- sys/kern/subr_bus.c
+++ sys/kern/subr_bus.c
@@ -49,6 +49,7 @@
 #include <sys/rman.h>
 #include <sys/selinfo.h>
 #include <sys/signalvar.h>
+#include <sys/smp.h>
 #include <sys/sysctl.h>
 #include <sys/systm.h>
 #include <sys/uio.h>
@@ -4079,6 +4080,23 @@
 }
 
 /**
+ * @brief Helper function for implementing BUS_GET_CPUS().
+ *
+ * This simple implementation of BUS_GET_CPUS() simply calls the
+ * BUS_GET_CPUS() method of the parent of @p dev.
+ */
+int
+bus_generic_get_cpus(device_t dev, device_t child, enum cpu_sets op,
+    cpuset_t *cpuset, int size)
+{
+
+	/* Propagate up the bus hierarchy until someone handles it. */
+	if (dev->parent != NULL)
+		return (BUS_GET_CPUS(dev->parent, child, op, cpuset, size));
+	return (EINVAL);
+}
+
+/**
  * @brief Helper function for implementing BUS_GET_DMA_TAG().
  *
  * This simple implementation of BUS_GET_DMA_TAG() simply calls the
@@ -4559,6 +4577,28 @@
 }
 
 /**
+ * @brief Wrapper function for BUS_GET_CPUS().
+ *
+ * This function simply calls the BUS_GET_CPUS() method of the
+ * parent of @p dev.
+ */
+int
+bus_get_cpus(device_t dev, enum cpu_sets op, cpuset_t *cpuset, int size)
+{
+	device_t parent;
+
+	/*
+	 * How should we handle size mismatch?
+	 */
+	if (size < sizeof(cpuset_t))
+	    return (ENXIO);
+	parent = device_get_parent(dev);
+	if (parent == NULL)
+		return (EINVAL);
+	return (BUS_GET_CPUS(parent, dev, op, cpuset, size));
+}
+
+/**
  * @brief Wrapper function for BUS_GET_DMA_TAG().
  *
  * This function simply calls the BUS_GET_DMA_TAG() method of the
@@ -4633,6 +4673,20 @@
 	return (-1);
 }
 
+static int
+root_get_cpus(device_t dev, device_t child, enum cpu_sets op, cpuset_t *cpuset, int size)
+{
+
+	switch (op) {
+	case INTR_CPUS:
+		/* Default to returning the set of all CPUs. */
+		*cpuset = all_cpus;
+		return (0);
+	default:
+		return (EINVAL);
+	}
+}
+
 static kobj_method_t root_methods[] = {
 	/* Device interface */
 	KOBJMETHOD(device_shutdown,	bus_generic_shutdown),
@@ -4645,6 +4699,7 @@
 	KOBJMETHOD(bus_write_ivar,	bus_generic_write_ivar),
 	KOBJMETHOD(bus_setup_intr,	root_setup_intr),
 	KOBJMETHOD(bus_child_present,	root_child_present),
+	KOBJMETHOD(bus_get_cpus,	root_get_cpus),
 
 	KOBJMETHOD_END
 };
Index: sys/sys/_cpuset.h
===================================================================
--- sys/sys/_cpuset.h
+++ sys/sys/_cpuset.h
@@ -32,6 +32,7 @@
 #ifndef _SYS__CPUSET_H_
 #define	_SYS__CPUSET_H_
 
+#include <sys/param.h>
 #include <sys/_bitset.h>
 
 #ifdef _KERNEL
Index: sys/sys/bus.h
===================================================================
--- sys/sys/bus.h
+++ sys/sys/bus.h
@@ -31,6 +31,7 @@
 
 #include <machine/_limits.h>
 #include <sys/_bus_dma.h>
+#include <sys/_cpuset.h>
 #include <sys/ioccom.h>
 
 /**
@@ -265,6 +266,16 @@
 	INTR_POLARITY_LOW = 2
 };
 
+/**
+ * CPU sets supported by bus_get_cpus().  Note that not all sets may be
+ * supported for a given device.  If a request is not supported by a
+ * device (or its parents), then bus_get_cpus() will fail with EINVAL.
+ */
+enum cpu_sets {
+	LOCAL_CPUS = 0,
+	INTR_CPUS
+};
+
 typedef int (*devop_t)(void);
 
 /**
@@ -381,6 +392,8 @@
 					int rid, struct resource *r);
 int	bus_generic_detach(device_t dev);
 void	bus_generic_driver_added(device_t dev, driver_t *driver);
+int	bus_generic_get_cpus(device_t dev, device_t child, enum cpu_sets op,
+			     cpuset_t *cpuset, int size);
 bus_dma_tag_t
 	bus_generic_get_dma_tag(device_t dev, device_t child);
 int	bus_generic_get_domain(device_t dev, device_t child, int *domain);
@@ -447,6 +460,7 @@
 			      struct resource *r);
 int	bus_deactivate_resource(device_t dev, int type, int rid,
 				struct resource *r);
+int	bus_get_cpus(device_t dev, enum cpu_sets op, cpuset_t *cpuset, int size);
 bus_dma_tag_t bus_get_dma_tag(device_t dev);
 int	bus_get_domain(device_t dev, int *domain);
 int	bus_release_resource(device_t dev, int type, int rid,
Index: sys/x86/x86/intr_machdep.c
===================================================================
--- sys/x86/x86/intr_machdep.c
+++ sys/x86/x86/intr_machdep.c
@@ -475,7 +475,7 @@
  * allocate CPUs round-robin.
  */
 
-static cpuset_t intr_cpus = CPUSET_T_INITIALIZER(0x1);
+cpuset_t intr_cpus = CPUSET_T_INITIALIZER(0x1);
 static int current_cpu;
 
 /*
Index: sys/x86/x86/nexus.c
===================================================================
--- sys/x86/x86/nexus.c
+++ sys/x86/x86/nexus.c
@@ -128,6 +128,7 @@
 static	int nexus_get_resource(device_t, device_t, int, int,
 			       rman_res_t *, rman_res_t *);
 static void nexus_delete_resource(device_t, device_t, int, int);
+static	int nexus_get_cpus(device_t, device_t, enum cpu_sets, cpuset_t *, int size);
 #ifdef DEV_APIC
 static	int nexus_alloc_msi(device_t pcib, device_t dev, int count, int maxcount, int *irqs);
 static	int nexus_release_msi(device_t pcib, device_t dev, int count, int *irqs);
@@ -164,6 +165,7 @@
 	DEVMETHOD(bus_set_resource,	nexus_set_resource),
 	DEVMETHOD(bus_get_resource,	nexus_get_resource),
 	DEVMETHOD(bus_delete_resource,	nexus_delete_resource),
+	DEVMETHOD(bus_get_cpus,		nexus_get_cpus),
 
 	/* pcib interface */
 #ifdef DEV_APIC
@@ -616,6 +618,21 @@
 	resource_list_delete(rl, type, rid);
 }
 
+static int
+nexus_get_cpus(device_t dev, device_t child, enum cpu_sets op, cpuset_t *cpuset, int size)
+{
+
+	switch (op) {
+#ifdef SMP
+	case INTR_CPUS:
+		*cpuset = intr_cpus;
+		return (0);
+#endif
+	default:
+		return (bus_generic_get_cpus(dev, child, op, cpuset, size));
+	}
+}
+
 /* Called from the MSI code to add new IRQs to the IRQ rman. */
 void
 nexus_add_irq(u_long irq)