diff --git a/hw/usb/bus.c b/hw/usb/bus.c
index f83d1de6cd49c7636b5e4cf9a20e84e26c903314..6aee26239ea1be013c83e73c2bb7beb3d435776d 100644
--- a/hw/usb/bus.c
+++ b/hw/usb/bus.c
@@ -67,7 +67,8 @@ const VMStateDescription vmstate_usb_device = {
     }
 };
 
-void usb_bus_new(USBBus *bus, USBBusOps *ops, DeviceState *host)
+void usb_bus_new(USBBus *bus, size_t bus_size,
+                 USBBusOps *ops, DeviceState *host)
 {
     qbus_create_inplace(&bus->qbus, TYPE_USB_BUS, host, NULL);
     bus->ops = ops;
diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
index e5523d54e01acadbac6d7dc51a8407d55c98f780..137e200202ec4b48bfe4e6d449b36bbbf9497d14 100644
--- a/hw/usb/hcd-ehci.c
+++ b/hw/usb/hcd-ehci.c
@@ -2520,7 +2520,7 @@ void usb_ehci_realize(EHCIState *s, DeviceState *dev, Error **errp)
         return;
     }
 
-    usb_bus_new(&s->bus, &ehci_bus_ops, dev);
+    usb_bus_new(&s->bus, sizeof(s->bus), &ehci_bus_ops, dev);
     for (i = 0; i < s->portnr; i++) {
         usb_register_port(&s->bus, &s->ports[i], s, i, &ehci_port_ops,
                           USB_SPEED_MASK_HIGH);
diff --git a/hw/usb/hcd-musb.c b/hw/usb/hcd-musb.c
index f91aa5580b7b1ad3f5171a63aad7084802017d84..66bc61ae1edb502f2b7b9ed4085033b8126f398c 100644
--- a/hw/usb/hcd-musb.c
+++ b/hw/usb/hcd-musb.c
@@ -383,7 +383,7 @@ struct MUSBState *musb_init(DeviceState *parent_device, int gpio_base)
 
     musb_reset(s);
 
-    usb_bus_new(&s->bus, &musb_bus_ops, parent_device);
+    usb_bus_new(&s->bus, sizeof(s->bus), &musb_bus_ops, parent_device);
     usb_register_port(&s->bus, &s->port, s, 0, &musb_port_ops,
                       USB_SPEED_MASK_LOW | USB_SPEED_MASK_FULL);
 
diff --git a/hw/usb/hcd-ohci.c b/hw/usb/hcd-ohci.c
index 39a25a72e1a0f37fdc27c37a89046bfe834bc545..35f0878409735acec151cd796fbecbdea4a10da0 100644
--- a/hw/usb/hcd-ohci.c
+++ b/hw/usb/hcd-ohci.c
@@ -1881,7 +1881,7 @@ static int usb_ohci_init(OHCIState *ohci, DeviceState *dev,
             return -1;
         }
     } else {
-        usb_bus_new(&ohci->bus, &ohci_bus_ops, dev);
+        usb_bus_new(&ohci->bus, sizeof(ohci->bus), &ohci_bus_ops, dev);
         for (i = 0; i < num_ports; i++) {
             usb_register_port(&ohci->bus, &ohci->rhport[i].port,
                               ohci, i, &ohci_port_ops,
diff --git a/hw/usb/hcd-uhci.c b/hw/usb/hcd-uhci.c
index 578b949c92385d7083946af2a5afe84aed5c2e00..becc7faec13b28afc45eaaf58ce5b00fda43e5af 100644
--- a/hw/usb/hcd-uhci.c
+++ b/hw/usb/hcd-uhci.c
@@ -1254,7 +1254,7 @@ static int usb_uhci_common_initfn(PCIDevice *dev)
             return -1;
         }
     } else {
-        usb_bus_new(&s->bus, &uhci_bus_ops, &s->dev.qdev);
+        usb_bus_new(&s->bus, sizeof(s->bus), &uhci_bus_ops, DEVICE(dev));
         for (i = 0; i < NB_PORTS; i++) {
             usb_register_port(&s->bus, &s->ports[i].port, s, i, &uhci_port_ops,
                               USB_SPEED_MASK_LOW | USB_SPEED_MASK_FULL);
diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
index be6b86e2ba3403aec0bc536e6560d0d823fee2a1..d5c6588053ab4525bdc5fcd11923a8af0ef6b82c 100644
--- a/hw/usb/hcd-xhci.c
+++ b/hw/usb/hcd-xhci.c
@@ -3309,7 +3309,7 @@ static void usb_xhci_init(XHCIState *xhci)
     usbports = MAX(xhci->numports_2, xhci->numports_3);
     xhci->numports = xhci->numports_2 + xhci->numports_3;
 
-    usb_bus_new(&xhci->bus, &xhci_bus_ops, dev);
+    usb_bus_new(&xhci->bus, sizeof(xhci->bus), &xhci_bus_ops, dev);
 
     for (i = 0; i < usbports; i++) {
         speedmask = 0;
diff --git a/include/hw/usb.h b/include/hw/usb.h
index 901b0da8b0387445e254eaa7736ea45efdaca235..1b8acba6f63009bf012a9512fd3607e04cea5d87 100644
--- a/include/hw/usb.h
+++ b/include/hw/usb.h
@@ -496,7 +496,8 @@ struct USBBusOps {
     void (*wakeup_endpoint)(USBBus *bus, USBEndpoint *ep, unsigned int stream);
 };
 
-void usb_bus_new(USBBus *bus, USBBusOps *ops, DeviceState *host);
+void usb_bus_new(USBBus *bus, size_t bus_size,
+                 USBBusOps *ops, DeviceState *host);
 USBBus *usb_bus_find(int busnr);
 void usb_legacy_register(const char *typename, const char *usbdevice_name,
                          USBDevice *(*usbdevice_init)(USBBus *bus,