diff --git a/hw/core/bus.c b/hw/core/bus.c
index 7f3d2a3dbd..2698f715bd 100644
--- a/hw/core/bus.c
+++ b/hw/core/bus.c
@@ -68,6 +68,28 @@ int qbus_walk_children(BusState *bus,
     return 0;
 }
 
+bool bus_is_in_reset(BusState *bus)
+{
+    return resettable_is_in_reset(OBJECT(bus));
+}
+
+static ResettableState *bus_get_reset_state(Object *obj)
+{
+    BusState *bus = BUS(obj);
+    return &bus->reset;
+}
+
+static void bus_reset_child_foreach(Object *obj, ResettableChildCallback cb,
+                                    void *opaque, ResetType type)
+{
+    BusState *bus = BUS(obj);
+    BusChild *kid;
+
+    QTAILQ_FOREACH(kid, &bus->children, sibling) {
+        cb(OBJECT(kid->child), opaque, type);
+    }
+}
+
 static void qbus_realize(BusState *bus, DeviceState *parent, const char *name)
 {
     const char *typename = object_get_typename(OBJECT(bus));
@@ -199,12 +221,83 @@ static char *default_bus_get_fw_dev_path(DeviceState *dev)
     return g_strdup(object_get_typename(OBJECT(dev)));
 }
 
+/**
+ * bus_phases_reset:
+ * Transition reset method for buses to allow moving
+ * smoothly from legacy reset method to multi-phases
+ */
+static void bus_phases_reset(BusState *bus)
+{
+    ResettableClass *rc = RESETTABLE_GET_CLASS(bus);
+
+    if (rc->phases.enter) {
+        rc->phases.enter(OBJECT(bus), RESET_TYPE_COLD);
+    }
+    if (rc->phases.hold) {
+        rc->phases.hold(OBJECT(bus));
+    }
+    if (rc->phases.exit) {
+        rc->phases.exit(OBJECT(bus));
+    }
+}
+
+static void bus_transitional_reset(Object *obj)
+{
+    BusClass *bc = BUS_GET_CLASS(obj);
+
+    /*
+     * This will call either @bus_phases_reset (for multi-phases transitioned
+     * buses) or a bus's specific method for not-yet transitioned buses.
+     * In both case, it does not reset children.
+     */
+    if (bc->reset) {
+        bc->reset(BUS(obj));
+    }
+}
+
+/**
+ * bus_get_transitional_reset:
+ * check if the bus's class is ready for multi-phase
+ */
+static ResettableTrFunction bus_get_transitional_reset(Object *obj)
+{
+    BusClass *dc = BUS_GET_CLASS(obj);
+    if (dc->reset != bus_phases_reset) {
+        /*
+         * dc->reset has been overridden by a subclass,
+         * the bus is not ready for multi phase yet.
+         */
+        return bus_transitional_reset;
+    }
+    return NULL;
+}
+
 static void bus_class_init(ObjectClass *class, void *data)
 {
     BusClass *bc = BUS_CLASS(class);
+    ResettableClass *rc = RESETTABLE_CLASS(class);
 
     class->unparent = bus_unparent;
     bc->get_fw_dev_path = default_bus_get_fw_dev_path;
+
+    rc->get_state = bus_get_reset_state;
+    rc->child_foreach = bus_reset_child_foreach;
+
+    /*
+     * @bus_phases_reset is put as the default reset method below, allowing
+     * to do the multi-phase transition from base classes to leaf classes. It
+     * allows a legacy-reset Bus class to extend a multi-phases-reset
+     * Bus class for the following reason:
+     * + If a base class B has been moved to multi-phase, then it does not
+     *   override this default reset method and may have defined phase methods.
+     * + A child class C (extending class B) which uses
+     *   bus_class_set_parent_reset() (or similar means) to override the
+     *   reset method will still work as expected. @bus_phases_reset function
+     *   will be registered as the parent reset method and effectively call
+     *   parent reset phases.
+     */
+    bc->reset = bus_phases_reset;
+    rc->get_transitional_function = bus_get_transitional_reset;
 }
 
 static void qbus_finalize(Object *obj)
@@ -223,6 +316,10 @@ static const TypeInfo bus_info = {
     .instance_init = qbus_initfn,
     .instance_finalize = qbus_finalize,
     .class_init = bus_class_init,
+    .interfaces = (InterfaceInfo[]) {
+        { TYPE_RESETTABLE_INTERFACE },
+        { }
+    },
 };
 
 static void bus_register_types(void)
diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index 29e8c6b8df..b2affd8f92 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -355,6 +355,28 @@ void qbus_reset_all_fn(void *opaque)
     qbus_reset_all(bus);
 }
 
+bool device_is_in_reset(DeviceState *dev)
+{
+    return resettable_is_in_reset(OBJECT(dev));
+}
+
+static ResettableState *device_get_reset_state(Object *obj)
+{
+    DeviceState *dev = DEVICE(obj);
+    return &dev->reset;
+}
+
+static void device_reset_child_foreach(Object *obj, ResettableChildCallback cb,
+                                       void *opaque, ResetType type)
+{
+    DeviceState *dev = DEVICE(obj);
+    BusState *bus;
+
+    QLIST_FOREACH(bus, &dev->child_bus, sibling) {
+        cb(OBJECT(bus), opaque, type);
+    }
+}
+
 /* can be used as ->unplug() callback for the simple cases */
 void qdev_simple_device_unplug_cb(HotplugHandler *hotplug_dev,
                                   DeviceState *dev, Error **errp)
@@ -1057,10 +1079,62 @@ device_vmstate_if_get_id(VMStateIf *obj)
     return qdev_get_dev_path(dev);
 }
 
+/**
+ * device_phases_reset:
+ * Transition reset method for devices to allow moving
+ * smoothly from legacy reset method to multi-phases
+ */
+static void device_phases_reset(DeviceState *dev)
+{
+    ResettableClass *rc = RESETTABLE_GET_CLASS(dev);
+
+    if (rc->phases.enter) {
+        rc->phases.enter(OBJECT(dev), RESET_TYPE_COLD);
+    }
+    if (rc->phases.hold) {
+        rc->phases.hold(OBJECT(dev));
+    }
+    if (rc->phases.exit) {
+        rc->phases.exit(OBJECT(dev));
+    }
+}
+
+static void device_transitional_reset(Object *obj)
+{
+    DeviceClass *dc = DEVICE_GET_CLASS(obj);
+
+    /*
+     * This will call either @device_phases_reset (for multi-phases transitioned
+     * devices) or a device's specific method for not-yet transitioned devices.
+     * In both case, it does not reset children.
+     */
+    if (dc->reset) {
+        dc->reset(DEVICE(obj));
+    }
+}
+
+/**
+ * device_get_transitional_reset:
+ * check if the device's class is ready for multi-phase
+ */
+static ResettableTrFunction device_get_transitional_reset(Object *obj)
+{
+    DeviceClass *dc = DEVICE_GET_CLASS(obj);
+    if (dc->reset != device_phases_reset) {
+        /*
+         * dc->reset has been overridden by a subclass,
+         * the device is not ready for multi phase yet.
+         */
+        return device_transitional_reset;
+    }
+    return NULL;
+}
+
 static void device_class_init(ObjectClass *class, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(class);
     VMStateIfClass *vc = VMSTATE_IF_CLASS(class);
+    ResettableClass *rc = RESETTABLE_CLASS(class);
 
     class->unparent = device_unparent;
 
@@ -1073,6 +1147,24 @@ static void device_class_init(ObjectClass *class, void *data)
     dc->hotpluggable = true;
     dc->user_creatable = true;
     vc->get_id = device_vmstate_if_get_id;
+    rc->get_state = device_get_reset_state;
+    rc->child_foreach = device_reset_child_foreach;
+
+    /*
+     * @device_phases_reset is put as the default reset method below, allowing
+     * to do the multi-phase transition from base classes to leaf classes. It
+     * allows a legacy-reset Device class to extend a multi-phases-reset
+     * Device class for the following reason:
+     * + If a base class B has been moved to multi-phase, then it does not
+     *   override this default reset method and may have defined phase methods.
+     * + A child class C (extending class B) which uses
+     *   device_class_set_parent_reset() (or similar means) to override the
+     *   reset method will still work as expected. @device_phases_reset function
+     *   will be registered as the parent reset method and effectively call
+     *   parent reset phases.
+     */
+    dc->reset = device_phases_reset;
+    rc->get_transitional_function = device_get_transitional_reset;
 
     object_class_property_add_bool(class, "realized",
                                    device_get_realized, device_set_realized,
@@ -1157,6 +1249,7 @@ static const TypeInfo device_type_info = {
     .class_size = sizeof(DeviceClass),
     .interfaces = (InterfaceInfo[]) {
         { TYPE_VMSTATE_IF },
+        { TYPE_RESETTABLE_INTERFACE },
         { }
     }
 };
diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
index 627d653dc1..09b7a441eb 100644
--- a/include/hw/qdev-core.h
+++ b/include/hw/qdev-core.h
@@ -5,6 +5,7 @@
 #include "qemu/bitmap.h"
 #include "qom/object.h"
 #include "hw/hotplug.h"
+#include "hw/resettable.h"
 
 enum {
     DEV_NVECTORS_UNSPECIFIED = -1,
@@ -122,6 +123,11 @@ typedef struct DeviceClass {
     bool hotpluggable;
 
     /* callbacks */
+    /*
+     * Reset method here is deprecated and replaced by methods in the
+     * resettable class interface to implement a multi-phase reset.
+     * TODO: remove once every reset callback is unused
+     */
     DeviceReset reset;
     DeviceRealize realize;
     DeviceUnrealize unrealize;
@@ -146,6 +152,7 @@ struct NamedGPIOList {
 /**
  * DeviceState:
  * @realized: Indicates whether the device has been fully constructed.
+ * @reset: ResettableState for the device; handled by Resettable interface.
  *
  * This structure should not be accessed directly.  We declare it here
  * so that it can be embedded in individual device state structures.
@@ -168,6 +175,7 @@ struct DeviceState {
     int num_child_bus;
     int instance_id_alias;
     int alias_required_for_version;
+    ResettableState reset;
 };
 
 struct DeviceListener {
@@ -220,6 +228,7 @@ typedef struct BusChild {
 /**
  * BusState:
  * @hotplug_handler: link to a hotplug handler associated with bus.
+ * @reset: ResettableState for the bus; handled by Resettable interface.
  */
 struct BusState {
     Object obj;
@@ -231,6 +240,7 @@ struct BusState {
     int num_children;
     QTAILQ_HEAD(, BusChild) children;
     QLIST_ENTRY(BusState) sibling;
+    ResettableState reset;
 };
 
 /**
@@ -417,6 +427,18 @@ void qdev_reset_all_fn(void *opaque);
 void qbus_reset_all(BusState *bus);
 void qbus_reset_all_fn(void *opaque);
 
+/**
+ * device_is_in_reset:
+ * Return true if the device @dev is currently being reset.
+ */
+bool device_is_in_reset(DeviceState *dev);
+
+/**
+ * bus_is_in_reset:
+ * Return true if the bus @bus is currently being reset.
+ */
+bool bus_is_in_reset(BusState *bus);
+
 /* This should go away once we get rid of the NULL bus hack */
 BusState *sysbus_get_default(void);
 
@@ -440,6 +462,11 @@ void device_legacy_reset(DeviceState *dev);
 
 void device_class_set_props(DeviceClass *dc, Property *props);
 
+/**
+ * device_class_set_parent_reset:
+ * TODO: remove the function when DeviceClass's reset method
+ * is not used anymore.
+ */
 void device_class_set_parent_reset(DeviceClass *dc,
                                    DeviceReset dev_reset,
                                    DeviceReset *parent_reset);
diff --git a/tests/Makefile.include b/tests/Makefile.include
index c6827ce8c2..a1bff5dcce 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -429,6 +429,7 @@ tests/fp/%:
 tests/test-qdev-global-props$(EXESUF): tests/test-qdev-global-props.o \
 	hw/core/qdev.o hw/core/qdev-properties.o hw/core/hotplug.o\
 	hw/core/bus.o \
+	hw/core/resettable.o \
 	hw/core/irq.o \
 	hw/core/fw-path-provider.o \
 	hw/core/reset.o \