diff --git a/hw/audio/intel-hda.c b/hw/audio/intel-hda.c
index 78f9d282e0..a6666c6cdf 100644
--- a/hw/audio/intel-hda.c
+++ b/hw/audio/intel-hda.c
@@ -40,11 +40,11 @@ static const TypeInfo hda_codec_bus_info = {
     .instance_size = sizeof(HDACodecBus),
 };
 
-void hda_codec_bus_init(DeviceState *dev, HDACodecBus *bus,
+void hda_codec_bus_init(DeviceState *dev, HDACodecBus *bus, size_t bus_size,
                         hda_codec_response_func response,
                         hda_codec_xfer_func xfer)
 {
-    qbus_create_inplace(&bus->qbus, TYPE_HDA_BUS, dev, NULL);
+    qbus_create_inplace(bus, bus_size, TYPE_HDA_BUS, dev, NULL);
     bus->response = response;
     bus->xfer = xfer;
 }
@@ -1142,7 +1142,7 @@ static int intel_hda_init(PCIDevice *pci)
         msi_init(&d->pci, 0x50, 1, true, false);
     }
 
-    hda_codec_bus_init(DEVICE(pci), &d->codecs,
+    hda_codec_bus_init(DEVICE(pci), &d->codecs, sizeof(d->codecs),
                        intel_hda_response, intel_hda_xfer);
 
     return 0;
diff --git a/hw/audio/intel-hda.h b/hw/audio/intel-hda.h
index 2544f0a344..d784bcf5fc 100644
--- a/hw/audio/intel-hda.h
+++ b/hw/audio/intel-hda.h
@@ -48,7 +48,7 @@ struct HDACodecDevice {
     uint32_t            cad;    /* codec address */
 };
 
-void hda_codec_bus_init(DeviceState *dev, HDACodecBus *bus,
+void hda_codec_bus_init(DeviceState *dev, HDACodecBus *bus, size_t bus_size,
                         hda_codec_response_func response,
                         hda_codec_xfer_func xfer);
 HDACodecDevice *hda_codec_find(HDACodecBus *bus, uint32_t cad);
diff --git a/hw/char/ipack.c b/hw/char/ipack.c
index f890471db5..b7e45bedb2 100644
--- a/hw/char/ipack.c
+++ b/hw/char/ipack.c
@@ -24,11 +24,12 @@ IPackDevice *ipack_device_find(IPackBus *bus, int32_t slot)
     return NULL;
 }
 
-void ipack_bus_new_inplace(IPackBus *bus, DeviceState *parent,
+void ipack_bus_new_inplace(IPackBus *bus, size_t bus_size,
+                           DeviceState *parent,
                            const char *name, uint8_t n_slots,
                            qemu_irq_handler handler)
 {
-    qbus_create_inplace(&bus->qbus, TYPE_IPACK_BUS, parent, name);
+    qbus_create_inplace(bus, bus_size, TYPE_IPACK_BUS, parent, name);
     bus->n_slots = n_slots;
     bus->set_irq = handler;
 }
diff --git a/hw/char/ipack.h b/hw/char/ipack.h
index f2b7a12e05..f8dc0f242a 100644
--- a/hw/char/ipack.h
+++ b/hw/char/ipack.h
@@ -72,7 +72,8 @@ extern const VMStateDescription vmstate_ipack_device;
     VMSTATE_STRUCT(_field, _state, 1, vmstate_ipack_device, IPackDevice)
 
 IPackDevice *ipack_device_find(IPackBus *bus, int32_t slot);
-void ipack_bus_new_inplace(IPackBus *bus, DeviceState *parent,
+void ipack_bus_new_inplace(IPackBus *bus, size_t bus_size,
+                           DeviceState *parent,
                            const char *name, uint8_t n_slots,
                            qemu_irq_handler handler);
 
diff --git a/hw/char/tpci200.c b/hw/char/tpci200.c
index d9e17b2956..e04ff26019 100644
--- a/hw/char/tpci200.c
+++ b/hw/char/tpci200.c
@@ -607,7 +607,7 @@ static int tpci200_initfn(PCIDevice *pci_dev)
     pci_register_bar(&s->dev, 4, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->las2);
     pci_register_bar(&s->dev, 5, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->las3);
 
-    ipack_bus_new_inplace(&s->bus, DEVICE(&s->dev), NULL,
+    ipack_bus_new_inplace(&s->bus, sizeof(s->bus), DEVICE(pci_dev), NULL,
                           N_MODULES, tpci200_set_irq);
 
     return 0;
diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
index f23f555dde..703f026370 100644
--- a/hw/char/virtio-serial-bus.c
+++ b/hw/char/virtio-serial-bus.c
@@ -911,8 +911,8 @@ static int virtio_serial_device_init(VirtIODevice *vdev)
                 sizeof(struct virtio_console_config));
 
     /* Spawn a new virtio-serial bus on which the ports will ride as devices */
-    qbus_create_inplace(&vser->bus.qbus, TYPE_VIRTIO_SERIAL_BUS, qdev,
-                        vdev->bus_name);
+    qbus_create_inplace(&vser->bus, sizeof(vser->bus), TYPE_VIRTIO_SERIAL_BUS,
+                        qdev, vdev->bus_name);
     vser->bus.qbus.allow_hotplug = 1;
     vser->bus.vser = vser;
     QTAILQ_INIT(&vser->ports);
diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index 758de9fccc..533f6dd122 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -470,10 +470,10 @@ static void bus_unparent(Object *obj)
     }
 }
 
-void qbus_create_inplace(void *bus, const char *typename,
+void qbus_create_inplace(void *bus, size_t size, const char *typename,
                          DeviceState *parent, const char *name)
 {
-    object_initialize(bus, typename);
+    object_initialize(bus, size, typename);
     qbus_realize(bus, parent, name);
 }
 
diff --git a/hw/core/sysbus.c b/hw/core/sysbus.c
index 9004d8c543..b84cd4a16f 100644
--- a/hw/core/sysbus.c
+++ b/hw/core/sysbus.c
@@ -276,8 +276,8 @@ static void main_system_bus_create(void)
     /* assign main_system_bus before qbus_create_inplace()
      * in order to make "if (bus != sysbus_get_default())" work */
     main_system_bus = g_malloc0(system_bus_info.instance_size);
-    qbus_create_inplace(main_system_bus, TYPE_SYSTEM_BUS, NULL,
-                        "main-system-bus");
+    qbus_create_inplace(main_system_bus, system_bus_info.instance_size,
+                        TYPE_SYSTEM_BUS, NULL, "main-system-bus");
     OBJECT(main_system_bus)->free = g_free;
     object_property_add_child(container_get(qdev_get_machine(),
                                             "/unattached"),
diff --git a/hw/cpu/icc_bus.c b/hw/cpu/icc_bus.c
index 8748cc5046..9a4ea7e2df 100644
--- a/hw/cpu/icc_bus.c
+++ b/hw/cpu/icc_bus.c
@@ -90,7 +90,8 @@ static void icc_bridge_init(Object *obj)
     ICCBridgeState *s = ICC_BRIGDE(obj);
     SysBusDevice *sb = SYS_BUS_DEVICE(obj);
 
-    qbus_create_inplace(&s->icc_bus, TYPE_ICC_BUS, DEVICE(s), "icc");
+    qbus_create_inplace(&s->icc_bus, sizeof(s->icc_bus), TYPE_ICC_BUS,
+                        DEVICE(s), "icc");
 
     /* Do not change order of registering regions,
      * APIC must be first registered region, board maps it by 0 index
diff --git a/hw/dma/xilinx_axidma.c b/hw/dma/xilinx_axidma.c
index 59e8e35a4c..d67c5f19a4 100644
--- a/hw/dma/xilinx_axidma.c
+++ b/hw/dma/xilinx_axidma.c
@@ -579,8 +579,10 @@ static void xilinx_axidma_init(Object *obj)
                              (Object **) &s->tx_control_dev, &errp);
     assert_no_error(errp);
 
-    object_initialize(&s->rx_data_dev, TYPE_XILINX_AXI_DMA_DATA_STREAM);
-    object_initialize(&s->rx_control_dev, TYPE_XILINX_AXI_DMA_CONTROL_STREAM);
+    object_initialize(&s->rx_data_dev, sizeof(s->rx_data_dev),
+                      TYPE_XILINX_AXI_DMA_DATA_STREAM);
+    object_initialize(&s->rx_control_dev, sizeof(s->rx_control_dev),
+                      TYPE_XILINX_AXI_DMA_CONTROL_STREAM);
     object_property_add_child(OBJECT(s), "axistream-connected-target",
                               (Object *)&s->rx_data_dev, &errp);
     assert_no_error(errp);
diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
index bba150fd74..a71a4ca47c 100644
--- a/hw/ide/ahci.c
+++ b/hw/ide/ahci.c
@@ -1175,7 +1175,7 @@ void ahci_init(AHCIState *s, DeviceState *qdev, AddressSpace *as, int ports)
     for (i = 0; i < s->ports; i++) {
         AHCIDevice *ad = &s->dev[i];
 
-        ide_bus_new(&ad->port, qdev, i, 1);
+        ide_bus_new(&ad->port, sizeof(ad->port), qdev, i, 1);
         ide_init2(&ad->port, irqs[i]);
 
         ad->hba = s;
diff --git a/hw/ide/cmd646.c b/hw/ide/cmd646.c
index d6ef7992d4..0500a7a1b6 100644
--- a/hw/ide/cmd646.c
+++ b/hw/ide/cmd646.c
@@ -289,7 +289,7 @@ static int pci_cmd646_ide_initfn(PCIDevice *dev)
 
     irq = qemu_allocate_irqs(cmd646_set_irq, d, 2);
     for (i = 0; i < 2; i++) {
-        ide_bus_new(&d->bus[i], DEVICE(dev), i, 2);
+        ide_bus_new(&d->bus[i], sizeof(d->bus[i]), DEVICE(dev), i, 2);
         ide_init2(&d->bus[i], irq[i]);
 
         bmdma_init(&d->bus[i], &d->bmdma[i], d);
diff --git a/hw/ide/internal.h b/hw/ide/internal.h
index 048a052143..5d1cf87742 100644
--- a/hw/ide/internal.h
+++ b/hw/ide/internal.h
@@ -576,7 +576,8 @@ void ide_atapi_cmd(IDEState *s);
 void ide_atapi_cmd_reply_end(IDEState *s);
 
 /* hw/ide/qdev.c */
-void ide_bus_new(IDEBus *idebus, DeviceState *dev, int bus_id, int max_units);
+void ide_bus_new(IDEBus *idebus, size_t idebus_size, DeviceState *dev,
+                 int bus_id, int max_units);
 IDEDevice *ide_create_drive(IDEBus *bus, int unit, DriveInfo *drive);
 
 #endif /* HW_IDE_INTERNAL_H */
diff --git a/hw/ide/isa.c b/hw/ide/isa.c
index bbc8c6b9c9..afc24d4728 100644
--- a/hw/ide/isa.c
+++ b/hw/ide/isa.c
@@ -70,7 +70,7 @@ static void isa_ide_realizefn(DeviceState *dev, Error **errp)
     ISADevice *isadev = ISA_DEVICE(dev);
     ISAIDEState *s = ISA_IDE(dev);
 
-    ide_bus_new(&s->bus, dev, 0, 2);
+    ide_bus_new(&s->bus, sizeof(s->bus), dev, 0, 2);
     ide_init_ioport(&s->bus, isadev, s->iobase, s->iobase2);
     isa_init_irq(isadev, &s->irq, s->isairq);
     ide_init2(&s->bus, s->irq);
diff --git a/hw/ide/macio.c b/hw/ide/macio.c
index ef4ba2b2c5..da94580aac 100644
--- a/hw/ide/macio.c
+++ b/hw/ide/macio.c
@@ -547,7 +547,7 @@ static void macio_ide_initfn(Object *obj)
     SysBusDevice *d = SYS_BUS_DEVICE(obj);
     MACIOIDEState *s = MACIO_IDE(obj);
 
-    ide_bus_new(&s->bus, DEVICE(obj), 0, 2);
+    ide_bus_new(&s->bus, sizeof(s->bus), DEVICE(obj), 0, 2);
     memory_region_init_io(&s->mem, obj, &pmac_ide_ops, s, "pmac-ide", 0x1000);
     sysbus_init_mmio(d, &s->mem);
     sysbus_init_irq(d, &s->irq);
diff --git a/hw/ide/mmio.c b/hw/ide/mmio.c
index d251ff983c..9f66a52599 100644
--- a/hw/ide/mmio.c
+++ b/hw/ide/mmio.c
@@ -137,7 +137,7 @@ static void mmio_ide_initfn(Object *obj)
     SysBusDevice *d = SYS_BUS_DEVICE(obj);
     MMIOState *s = MMIO_IDE(obj);
 
-    ide_bus_new(&s->bus, DEVICE(obj), 0, 2);
+    ide_bus_new(&s->bus, sizeof(s->bus), DEVICE(obj), 0, 2);
     sysbus_init_irq(d, &s->irq);
 }
 
diff --git a/hw/ide/piix.c b/hw/ide/piix.c
index e6e6c0bb7a..ab36749417 100644
--- a/hw/ide/piix.c
+++ b/hw/ide/piix.c
@@ -136,7 +136,7 @@ static void pci_piix_init_ports(PCIIDEState *d) {
     int i;
 
     for (i = 0; i < 2; i++) {
-        ide_bus_new(&d->bus[i], DEVICE(d), i, 2);
+        ide_bus_new(&d->bus[i], sizeof(d->bus[i]), DEVICE(d), i, 2);
         ide_init_ioport(&d->bus[i], NULL, port_info[i].iobase,
                         port_info[i].iobase2);
         ide_init2(&d->bus[i], isa_get_irq(NULL, port_info[i].isairq));
diff --git a/hw/ide/qdev.c b/hw/ide/qdev.c
index 1d84e15378..18c4b7eca9 100644
--- a/hw/ide/qdev.c
+++ b/hw/ide/qdev.c
@@ -47,9 +47,10 @@ static const TypeInfo ide_bus_info = {
     .class_init = ide_bus_class_init,
 };
 
-void ide_bus_new(IDEBus *idebus, DeviceState *dev, int bus_id, int max_units)
+void ide_bus_new(IDEBus *idebus, size_t idebus_size, DeviceState *dev,
+                 int bus_id, int max_units)
 {
-    qbus_create_inplace(&idebus->qbus, TYPE_IDE_BUS, dev, NULL);
+    qbus_create_inplace(idebus, idebus_size, TYPE_IDE_BUS, dev, NULL);
     idebus->bus_id = bus_id;
     idebus->max_units = max_units;
 }
diff --git a/hw/ide/via.c b/hw/ide/via.c
index e5fb2970e1..99468c773e 100644
--- a/hw/ide/via.c
+++ b/hw/ide/via.c
@@ -159,7 +159,7 @@ static void vt82c686b_init_ports(PCIIDEState *d) {
     int i;
 
     for (i = 0; i < 2; i++) {
-        ide_bus_new(&d->bus[i], DEVICE(d), i, 2);
+        ide_bus_new(&d->bus[i], sizeof(d->bus[i]), DEVICE(d), i, 2);
         ide_init_ioport(&d->bus[i], NULL, port_info[i].iobase,
                         port_info[i].iobase2);
         ide_init2(&d->bus[i], isa_get_irq(NULL, port_info[i].isairq));
diff --git a/hw/intc/xics.c b/hw/intc/xics.c
index 31868c4d18..bb018d1829 100644
--- a/hw/intc/xics.c
+++ b/hw/intc/xics.c
@@ -661,7 +661,7 @@ static void xics_realize(DeviceState *dev, Error **errp)
     icp->ss = g_malloc0(icp->nr_servers*sizeof(ICPState));
     for (i = 0; i < icp->nr_servers; i++) {
         char buffer[32];
-        object_initialize(&icp->ss[i], TYPE_ICP);
+        object_initialize(&icp->ss[i], sizeof(icp->ss[i]), TYPE_ICP);
         snprintf(buffer, sizeof(buffer), "icp[%d]", i);
         object_property_add_child(OBJECT(icp), buffer, OBJECT(&icp->ss[i]), NULL);
         qdev_init_nofail(DEVICE(&icp->ss[i]));
diff --git a/hw/misc/macio/cuda.c b/hw/misc/macio/cuda.c
index c811b9519b..bc71aa7ccd 100644
--- a/hw/misc/macio/cuda.c
+++ b/hw/misc/macio/cuda.c
@@ -711,8 +711,8 @@ static void cuda_initfn(Object *obj)
         s->timers[i].index = i;
     }
 
-    qbus_create_inplace((BusState *)&s->adb_bus, TYPE_ADB_BUS, DEVICE(obj),
-                        "adb.0");
+    qbus_create_inplace(&s->adb_bus, sizeof(s->adb_bus), TYPE_ADB_BUS,
+                        DEVICE(obj), "adb.0");
 }
 
 static void cuda_class_init(ObjectClass *oc, void *data)
diff --git a/hw/misc/macio/macio.c b/hw/misc/macio/macio.c
index 9cc33d8f96..7f99aa0d5c 100644
--- a/hw/misc/macio/macio.c
+++ b/hw/misc/macio/macio.c
@@ -202,11 +202,12 @@ static int macio_oldworld_initfn(PCIDevice *d)
     return 0;
 }
 
-static void macio_init_ide(MacIOState *s, MACIOIDEState *ide, int index)
+static void macio_init_ide(MacIOState *s, MACIOIDEState *ide, size_t ide_size,
+                           int index)
 {
     gchar *name;
 
-    object_initialize(ide, TYPE_MACIO_IDE);
+    object_initialize(ide, ide_size, TYPE_MACIO_IDE);
     qdev_set_parent_bus(DEVICE(ide), sysbus_get_default());
     memory_region_add_subregion(&s->bar, 0x1f000 + ((index + 1) * 0x1000),
                                 &ide->mem);
@@ -224,13 +225,13 @@ static void macio_oldworld_init(Object *obj)
 
     qdev_init_gpio_out(DEVICE(obj), os->irqs, ARRAY_SIZE(os->irqs));
 
-    object_initialize(&os->nvram, TYPE_MACIO_NVRAM);
+    object_initialize(&os->nvram, sizeof(os->nvram), TYPE_MACIO_NVRAM);
     dev = DEVICE(&os->nvram);
     qdev_prop_set_uint32(dev, "size", 0x2000);
     qdev_prop_set_uint32(dev, "it_shift", 4);
 
     for (i = 0; i < 2; i++) {
-        macio_init_ide(s, &os->ide[i], i);
+        macio_init_ide(s, &os->ide[i], sizeof(os->ide[i]), i);
     }
 }
 
@@ -310,7 +311,7 @@ static void macio_newworld_init(Object *obj)
     qdev_init_gpio_out(DEVICE(obj), ns->irqs, ARRAY_SIZE(ns->irqs));
 
     for (i = 0; i < 2; i++) {
-        macio_init_ide(s, &ns->ide[i], i);
+        macio_init_ide(s, &ns->ide[i], sizeof(ns->ide[i]), i);
     }
 }
 
@@ -321,7 +322,7 @@ static void macio_instance_init(Object *obj)
 
     memory_region_init(&s->bar, NULL, "macio", 0x80000);
 
-    object_initialize(&s->cuda, TYPE_CUDA);
+    object_initialize(&s->cuda, sizeof(s->cuda), TYPE_CUDA);
     qdev_set_parent_bus(DEVICE(&s->cuda), sysbus_get_default());
     object_property_add_child(obj, "cuda", OBJECT(&s->cuda), NULL);
 
diff --git a/hw/net/xilinx_axienet.c b/hw/net/xilinx_axienet.c
index f173429ecc..3eb7715c22 100644
--- a/hw/net/xilinx_axienet.c
+++ b/hw/net/xilinx_axienet.c
@@ -990,8 +990,10 @@ static void xilinx_enet_init(Object *obj)
                              (Object **) &s->tx_control_dev, &errp);
     assert_no_error(errp);
 
-    object_initialize(&s->rx_data_dev, TYPE_XILINX_AXI_ENET_DATA_STREAM);
-    object_initialize(&s->rx_control_dev, TYPE_XILINX_AXI_ENET_CONTROL_STREAM);
+    object_initialize(&s->rx_data_dev, sizeof(s->rx_data_dev),
+                      TYPE_XILINX_AXI_ENET_DATA_STREAM);
+    object_initialize(&s->rx_control_dev, sizeof(s->rx_control_dev),
+                      TYPE_XILINX_AXI_ENET_CONTROL_STREAM);
     object_property_add_child(OBJECT(s), "axistream-connected-target",
                               (Object *)&s->rx_data_dev, &errp);
     assert_no_error(errp);
diff --git a/hw/pci-host/prep.c b/hw/pci-host/prep.c
index e120058511..0e71fdbfb1 100644
--- a/hw/pci-host/prep.c
+++ b/hw/pci-host/prep.c
@@ -155,11 +155,11 @@ static void raven_pcihost_initfn(Object *obj)
     MemoryRegion *address_space_io = get_system_io();
     DeviceState *pci_dev;
 
-    pci_bus_new_inplace(&s->pci_bus, DEVICE(obj), NULL,
+    pci_bus_new_inplace(&s->pci_bus, sizeof(s->pci_bus), DEVICE(obj), NULL,
                         address_space_mem, address_space_io, 0, TYPE_PCI_BUS);
     h->bus = &s->pci_bus;
 
-    object_initialize(&s->pci_dev, TYPE_RAVEN_PCI_DEVICE);
+    object_initialize(&s->pci_dev, sizeof(s->pci_dev), TYPE_RAVEN_PCI_DEVICE);
     pci_dev = DEVICE(&s->pci_dev);
     qdev_set_parent_bus(pci_dev, BUS(&s->pci_bus));
     object_property_set_int(OBJECT(&s->pci_dev), PCI_DEVFN(0, 0), "addr",
diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
index 12314d8dfe..e7d9712535 100644
--- a/hw/pci-host/q35.c
+++ b/hw/pci-host/q35.c
@@ -133,7 +133,7 @@ static void q35_host_initfn(Object *obj)
     memory_region_init_io(&phb->data_mem, obj, &pci_host_data_le_ops, phb,
                           "pci-conf-data", 4);
 
-    object_initialize(&s->mch, TYPE_MCH_PCI_DEVICE);
+    object_initialize(&s->mch, sizeof(s->mch), TYPE_MCH_PCI_DEVICE);
     object_property_add_child(OBJECT(s), "mch", OBJECT(&s->mch), NULL);
     qdev_prop_set_uint32(DEVICE(&s->mch), "addr", PCI_DEVFN(0, 0));
     qdev_prop_set_bit(DEVICE(&s->mch), "multifunction", false);
diff --git a/hw/pci-host/versatile.c b/hw/pci-host/versatile.c
index 9238d39b00..6b28929d26 100644
--- a/hw/pci-host/versatile.c
+++ b/hw/pci-host/versatile.c
@@ -384,12 +384,12 @@ static void pci_vpb_init(Object *obj)
     memory_region_init(&s->pci_io_space, OBJECT(s), "pci_io", 1ULL << 32);
     memory_region_init(&s->pci_mem_space, OBJECT(s), "pci_mem", 1ULL << 32);
 
-    pci_bus_new_inplace(&s->pci_bus, DEVICE(obj), "pci",
+    pci_bus_new_inplace(&s->pci_bus, sizeof(s->pci_bus), DEVICE(obj), "pci",
                         &s->pci_mem_space, &s->pci_io_space,
                         PCI_DEVFN(11, 0), TYPE_PCI_BUS);
     h->bus = &s->pci_bus;
 
-    object_initialize(&s->pci_dev, TYPE_VERSATILE_PCI_HOST);
+    object_initialize(&s->pci_dev, sizeof(s->pci_dev), TYPE_VERSATILE_PCI_HOST);
     qdev_set_parent_bus(DEVICE(&s->pci_dev), BUS(&s->pci_bus));
 
     /* Window sizes for VersatilePB; realview_pci's init will override */
diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 4c004f5daa..e688f4a342 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -312,13 +312,13 @@ bool pci_bus_is_root(PCIBus *bus)
     return !bus->parent_dev;
 }
 
-void pci_bus_new_inplace(PCIBus *bus, DeviceState *parent,
+void pci_bus_new_inplace(PCIBus *bus, size_t bus_size, DeviceState *parent,
                          const char *name,
                          MemoryRegion *address_space_mem,
                          MemoryRegion *address_space_io,
                          uint8_t devfn_min, const char *typename)
 {
-    qbus_create_inplace(bus, typename, parent, name);
+    qbus_create_inplace(bus, bus_size, typename, parent, name);
     pci_bus_init(bus, parent, name, address_space_mem,
                  address_space_io, devfn_min);
 }
diff --git a/hw/pci/pci_bridge.c b/hw/pci/pci_bridge.c
index a90671d2f2..e6b22b860f 100644
--- a/hw/pci/pci_bridge.c
+++ b/hw/pci/pci_bridge.c
@@ -367,7 +367,8 @@ int pci_bridge_initfn(PCIDevice *dev, const char *typename)
 	    br->bus_name = dev->qdev.id;
     }
 
-    qbus_create_inplace(&sec_bus->qbus, typename, &dev->qdev, br->bus_name);
+    qbus_create_inplace(sec_bus, sizeof(br->sec_bus), typename, DEVICE(dev),
+                        br->bus_name);
     sec_bus->parent_dev = dev;
     sec_bus->map_irq = br->map_irq ? br->map_irq : pci_swizzle_map_irq_fn;
     sec_bus->address_space_mem = &br->address_space_mem;
diff --git a/hw/s390x/event-facility.c b/hw/s390x/event-facility.c
index 0faade0766..a3aceef8f5 100644
--- a/hw/s390x/event-facility.c
+++ b/hw/s390x/event-facility.c
@@ -324,8 +324,8 @@ static int init_event_facility(S390SCLPDevice *sdev)
     sdev->event_pending = event_pending;
 
     /* Spawn a new sclp-events facility */
-    qbus_create_inplace(&event_facility->sbus.qbus,
-                        TYPE_SCLP_EVENTS_BUS, (DeviceState *)sdev, NULL);
+    qbus_create_inplace(&event_facility->sbus, sizeof(event_facility->sbus),
+                        TYPE_SCLP_EVENTS_BUS, DEVICE(sdev), NULL);
     event_facility->sbus.qbus.allow_hotplug = 0;
     event_facility->qdev = (DeviceState *) sdev;
 
diff --git a/hw/s390x/s390-virtio-bus.c b/hw/s390x/s390-virtio-bus.c
index f0aa9414f2..6a831114da 100644
--- a/hw/s390x/s390-virtio-bus.c
+++ b/hw/s390x/s390-virtio-bus.c
@@ -47,7 +47,8 @@
 
 #define VIRTIO_EXT_CODE   0x2603
 
-static void virtio_s390_bus_new(VirtioBusState *bus, VirtIOS390Device *dev);
+static void virtio_s390_bus_new(VirtioBusState *bus, size_t bus_size,
+                                VirtIOS390Device *dev);
 
 static const TypeInfo s390_virtio_bus_info = {
     .name = TYPE_S390_VIRTIO_BUS,
@@ -170,7 +171,7 @@ static int s390_virtio_net_init(VirtIOS390Device *s390_dev)
 static void s390_virtio_net_instance_init(Object *obj)
 {
     VirtIONetS390 *dev = VIRTIO_NET_S390(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_NET);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_NET);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 }
 
@@ -189,7 +190,7 @@ static int s390_virtio_blk_init(VirtIOS390Device *s390_dev)
 static void s390_virtio_blk_instance_init(Object *obj)
 {
     VirtIOBlkS390 *dev = VIRTIO_BLK_S390(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_BLK);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_BLK);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 }
 
@@ -230,7 +231,7 @@ static int s390_virtio_serial_init(VirtIOS390Device *s390_dev)
 static void s390_virtio_serial_instance_init(Object *obj)
 {
     VirtIOSerialS390 *dev = VIRTIO_SERIAL_S390(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_SERIAL);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_SERIAL);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 }
 
@@ -262,7 +263,7 @@ static int s390_virtio_scsi_init(VirtIOS390Device *s390_dev)
 static void s390_virtio_scsi_instance_init(Object *obj)
 {
     VirtIOSCSIS390 *dev = VIRTIO_SCSI_S390(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_SCSI);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_SCSI);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 }
 
@@ -283,7 +284,7 @@ static int s390_vhost_scsi_init(VirtIOS390Device *s390_dev)
 static void s390_vhost_scsi_instance_init(Object *obj)
 {
     VHostSCSIS390 *dev = VHOST_SCSI_S390(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VHOST_SCSI);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VHOST_SCSI);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 }
 #endif
@@ -309,7 +310,7 @@ static int s390_virtio_rng_init(VirtIOS390Device *s390_dev)
 static void s390_virtio_rng_instance_init(Object *obj)
 {
     VirtIORNGS390 *dev = VIRTIO_RNG_S390(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_RNG);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_RNG);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
     object_property_add_link(obj, "rng", TYPE_RNG_BACKEND,
                              (Object **)&dev->vdev.conf.rng, NULL);
@@ -585,7 +586,7 @@ static int s390_virtio_busdev_init(DeviceState *dev)
     VirtIOS390Device *_dev = (VirtIOS390Device *)dev;
     VirtIOS390DeviceClass *_info = VIRTIO_S390_DEVICE_GET_CLASS(dev);
 
-    virtio_s390_bus_new(&_dev->bus, _dev);
+    virtio_s390_bus_new(&_dev->bus, sizeof(_dev->bus), _dev);
 
     return _info->init(_dev);
 }
@@ -691,14 +692,15 @@ static const TypeInfo s390_virtio_bridge_info = {
 
 /* virtio-s390-bus */
 
-static void virtio_s390_bus_new(VirtioBusState *bus, VirtIOS390Device *dev)
+static void virtio_s390_bus_new(VirtioBusState *bus, size_t bus_size,
+                                VirtIOS390Device *dev)
 {
     DeviceState *qdev = DEVICE(dev);
     BusState *qbus;
     char virtio_bus_name[] = "virtio-bus";
 
-    qbus_create_inplace((BusState *)bus, TYPE_VIRTIO_S390_BUS, qdev,
-                        virtio_bus_name);
+    qbus_create_inplace(bus, bus_size, TYPE_VIRTIO_S390_BUS,
+                        qdev, virtio_bus_name);
     qbus = BUS(bus);
     qbus->allow_hotplug = 1;
 }
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index 8835bd4339..cd67db5e5b 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -27,7 +27,8 @@
 #include "virtio-ccw.h"
 #include "trace.h"
 
-static void virtio_ccw_bus_new(VirtioBusState *bus, VirtioCcwDevice *dev);
+static void virtio_ccw_bus_new(VirtioBusState *bus, size_t bus_size,
+                               VirtioCcwDevice *dev);
 
 static int virtual_css_bus_reset(BusState *qbus)
 {
@@ -659,7 +660,7 @@ static int virtio_ccw_net_init(VirtioCcwDevice *ccw_dev)
 static void virtio_ccw_net_instance_init(Object *obj)
 {
     VirtIONetCcw *dev = VIRTIO_NET_CCW(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_NET);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_NET);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 }
 
@@ -679,7 +680,7 @@ static int virtio_ccw_blk_init(VirtioCcwDevice *ccw_dev)
 static void virtio_ccw_blk_instance_init(Object *obj)
 {
     VirtIOBlkCcw *dev = VIRTIO_BLK_CCW(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_BLK);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_BLK);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 }
 
@@ -712,7 +713,7 @@ static int virtio_ccw_serial_init(VirtioCcwDevice *ccw_dev)
 static void virtio_ccw_serial_instance_init(Object *obj)
 {
     VirtioSerialCcw *dev = VIRTIO_SERIAL_CCW(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_SERIAL);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_SERIAL);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 }
 
@@ -758,7 +759,7 @@ static void balloon_ccw_stats_set_poll_interval(Object *obj, struct Visitor *v,
 static void virtio_ccw_balloon_instance_init(Object *obj)
 {
     VirtIOBalloonCcw *dev = VIRTIO_BALLOON_CCW(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_BALLOON);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_BALLOON);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 
     object_property_add(obj, "guest-stats", "guest statistics",
@@ -798,7 +799,7 @@ static int virtio_ccw_scsi_init(VirtioCcwDevice *ccw_dev)
 static void virtio_ccw_scsi_instance_init(Object *obj)
 {
     VirtIOSCSICcw *dev = VIRTIO_SCSI_CCW(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_SCSI);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_SCSI);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 }
 
@@ -819,7 +820,7 @@ static int vhost_ccw_scsi_init(VirtioCcwDevice *ccw_dev)
 static void vhost_ccw_scsi_instance_init(Object *obj)
 {
     VHostSCSICcw *dev = VHOST_SCSI_CCW(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VHOST_SCSI);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VHOST_SCSI);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 }
 #endif
@@ -1170,7 +1171,7 @@ static const TypeInfo vhost_ccw_scsi = {
 static void virtio_ccw_rng_instance_init(Object *obj)
 {
     VirtIORNGCcw *dev = VIRTIO_RNG_CCW(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_RNG);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_RNG);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
     object_property_add_link(obj, "rng", TYPE_RNG_BACKEND,
                              (Object **)&dev->vdev.conf.rng, NULL);
@@ -1209,7 +1210,7 @@ static int virtio_ccw_busdev_init(DeviceState *dev)
     VirtioCcwDevice *_dev = (VirtioCcwDevice *)dev;
     VirtIOCCWDeviceClass *_info = VIRTIO_CCW_DEVICE_GET_CLASS(dev);
 
-    virtio_ccw_bus_new(&_dev->bus, _dev);
+    virtio_ccw_bus_new(&_dev->bus, sizeof(_dev->bus), _dev);
 
     return _info->init(_dev);
 }
@@ -1289,14 +1290,15 @@ static const TypeInfo virtual_css_bridge_info = {
 
 /* virtio-ccw-bus */
 
-static void virtio_ccw_bus_new(VirtioBusState *bus, VirtioCcwDevice *dev)
+static void virtio_ccw_bus_new(VirtioBusState *bus, size_t bus_size,
+                               VirtioCcwDevice *dev)
 {
     DeviceState *qdev = DEVICE(dev);
     BusState *qbus;
     char virtio_bus_name[] = "virtio-bus";
 
-    qbus_create_inplace((BusState *)bus, TYPE_VIRTIO_CCW_BUS, qdev,
-                        virtio_bus_name);
+    qbus_create_inplace(bus, bus_size, TYPE_VIRTIO_CCW_BUS,
+                        qdev, virtio_bus_name);
     qbus = BUS(bus);
     qbus->allow_hotplug = 1;
 }
diff --git a/hw/scsi/esp-pci.c b/hw/scsi/esp-pci.c
index d7ec1736c0..99bf8ec446 100644
--- a/hw/scsi/esp-pci.c
+++ b/hw/scsi/esp-pci.c
@@ -363,7 +363,7 @@ static int esp_pci_scsi_init(PCIDevice *dev)
     pci_register_bar(dev, 0, PCI_BASE_ADDRESS_SPACE_IO, &pci->io);
     s->irq = dev->irq[0];
 
-    scsi_bus_new(&s->bus, d, &esp_pci_scsi_info, NULL);
+    scsi_bus_new(&s->bus, sizeof(s->bus), d, &esp_pci_scsi_info, NULL);
     if (!d->hotplugged) {
         scsi_bus_legacy_handle_cmdline(&s->bus, &err);
         if (err != NULL) {
diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c
index 101e957d4d..2d150bfe48 100644
--- a/hw/scsi/esp.c
+++ b/hw/scsi/esp.c
@@ -688,7 +688,7 @@ static void sysbus_esp_realize(DeviceState *dev, Error **errp)
 
     qdev_init_gpio_in(dev, sysbus_esp_gpio_demux, 2);
 
-    scsi_bus_new(&s->bus, dev, &esp_scsi_info, NULL);
+    scsi_bus_new(&s->bus, sizeof(s->bus), dev, &esp_scsi_info, NULL);
     scsi_bus_legacy_handle_cmdline(&s->bus, &err);
     if (err != NULL) {
         error_propagate(errp, err);
diff --git a/hw/scsi/lsi53c895a.c b/hw/scsi/lsi53c895a.c
index 611f2aa1b2..0c36842729 100644
--- a/hw/scsi/lsi53c895a.c
+++ b/hw/scsi/lsi53c895a.c
@@ -2117,7 +2117,7 @@ static int lsi_scsi_init(PCIDevice *dev)
     pci_register_bar(dev, 2, PCI_BASE_ADDRESS_SPACE_MEMORY, &s->ram_io);
     QTAILQ_INIT(&s->queue);
 
-    scsi_bus_new(&s->bus, d, &lsi_scsi_info, NULL);
+    scsi_bus_new(&s->bus, sizeof(s->bus), d, &lsi_scsi_info, NULL);
     if (!d->hotplugged) {
         scsi_bus_legacy_handle_cmdline(&s->bus, &err);
         if (err != NULL) {
diff --git a/hw/scsi/megasas.c b/hw/scsi/megasas.c
index a6d5285911..09b51b387b 100644
--- a/hw/scsi/megasas.c
+++ b/hw/scsi/megasas.c
@@ -2171,7 +2171,8 @@ static int megasas_scsi_init(PCIDevice *dev)
         s->frames[i].state = s;
     }
 
-    scsi_bus_new(&s->bus, DEVICE(dev), &megasas_scsi_info, NULL);
+    scsi_bus_new(&s->bus, sizeof(s->bus), DEVICE(dev),
+                 &megasas_scsi_info, NULL);
     if (!d->hotplugged) {
         scsi_bus_legacy_handle_cmdline(&s->bus, &err);
         if (err != NULL) {
diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
index fbf9173fb4..5cd6137046 100644
--- a/hw/scsi/scsi-bus.c
+++ b/hw/scsi/scsi-bus.c
@@ -72,10 +72,10 @@ static void scsi_device_unit_attention_reported(SCSIDevice *s)
 }
 
 /* Create a scsi bus, and attach devices to it.  */
-void scsi_bus_new(SCSIBus *bus, DeviceState *host, const SCSIBusInfo *info,
-                  const char *bus_name)
+void scsi_bus_new(SCSIBus *bus, size_t bus_size, DeviceState *host,
+                  const SCSIBusInfo *info, const char *bus_name)
 {
-    qbus_create_inplace(&bus->qbus, TYPE_SCSI_BUS, host, bus_name);
+    qbus_create_inplace(bus, bus_size, TYPE_SCSI_BUS, host, bus_name);
     bus->busnr = next_scsi_bus++;
     bus->info = info;
     bus->qbus.allow_hotplug = 1;
diff --git a/hw/scsi/spapr_vscsi.c b/hw/scsi/spapr_vscsi.c
index e9090e5c72..b2fcd4b3e3 100644
--- a/hw/scsi/spapr_vscsi.c
+++ b/hw/scsi/spapr_vscsi.c
@@ -1020,7 +1020,8 @@ static int spapr_vscsi_init(VIOsPAPRDevice *dev)
 
     dev->crq.SendFunc = vscsi_do_crq;
 
-    scsi_bus_new(&s->bus, &dev->qdev, &vscsi_scsi_info, NULL);
+    scsi_bus_new(&s->bus, sizeof(s->bus), DEVICE(dev),
+                 &vscsi_scsi_info, NULL);
     if (!dev->qdev.hotplugged) {
         scsi_bus_legacy_handle_cmdline(&s->bus, &err);
         if (err != NULL) {
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index 05da56bd24..3bd690d128 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -627,7 +627,8 @@ static int virtio_scsi_device_init(VirtIODevice *vdev)
         return ret;
     }
 
-    scsi_bus_new(&s->bus, qdev, &virtio_scsi_scsi_info, vdev->bus_name);
+    scsi_bus_new(&s->bus, sizeof(s->bus), qdev,
+                 &virtio_scsi_scsi_info, vdev->bus_name);
 
     if (!qdev->hotplugged) {
         scsi_bus_legacy_handle_cmdline(&s->bus, &err);
diff --git a/hw/scsi/vmw_pvscsi.c b/hw/scsi/vmw_pvscsi.c
index d42b35941b..819d671ba2 100644
--- a/hw/scsi/vmw_pvscsi.c
+++ b/hw/scsi/vmw_pvscsi.c
@@ -1088,7 +1088,8 @@ pvscsi_init(PCIDevice *pci_dev)
         return -ENOMEM;
     }
 
-    scsi_bus_new(&s->bus, &pci_dev->qdev, &pvscsi_scsi_info, NULL);
+    scsi_bus_new(&s->bus, sizeof(s->bus), DEVICE(pci_dev),
+                 &pvscsi_scsi_info, NULL);
     pvscsi_reset_state(s);
 
     return 0;
diff --git a/hw/usb/bus.c b/hw/usb/bus.c
index f83d1de6cd..82ca6a13e8 100644
--- a/hw/usb/bus.c
+++ b/hw/usb/bus.c
@@ -67,9 +67,10 @@ 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);
+    qbus_create_inplace(bus, bus_size, TYPE_USB_BUS, host, NULL);
     bus->ops = ops;
     bus->busnr = next_usb_bus++;
     bus->qbus.allow_hotplug = 1; /* Yes, we can */
diff --git a/hw/usb/dev-smartcard-reader.c b/hw/usb/dev-smartcard-reader.c
index 2233c548fa..8c7a61ebe1 100644
--- a/hw/usb/dev-smartcard-reader.c
+++ b/hw/usb/dev-smartcard-reader.c
@@ -1309,7 +1309,8 @@ static int ccid_initfn(USBDevice *dev)
 
     usb_desc_create_serial(dev);
     usb_desc_init(dev);
-    qbus_create_inplace(&s->bus.qbus, TYPE_CCID_BUS, &dev->qdev, NULL);
+    qbus_create_inplace(&s->bus, sizeof(s->bus), TYPE_CCID_BUS, DEVICE(dev),
+                        NULL);
     s->intr = usb_ep_get(dev, USB_TOKEN_IN, CCID_INT_IN_EP);
     s->bus.qbus.allow_hotplug = 1;
     s->card = NULL;
diff --git a/hw/usb/dev-storage.c b/hw/usb/dev-storage.c
index a8dc2fa960..1d81ac2a6b 100644
--- a/hw/usb/dev-storage.c
+++ b/hw/usb/dev-storage.c
@@ -618,7 +618,8 @@ static int usb_msd_initfn_storage(USBDevice *dev)
 
     usb_desc_create_serial(dev);
     usb_desc_init(dev);
-    scsi_bus_new(&s->bus, &s->dev.qdev, &usb_msd_scsi_info_storage, NULL);
+    scsi_bus_new(&s->bus, sizeof(s->bus), DEVICE(dev),
+                 &usb_msd_scsi_info_storage, NULL);
     scsi_dev = scsi_bus_legacy_add_drive(&s->bus, bs, 0, !!s->removable,
                                          s->conf.bootindex, dev->serial,
                                          &err);
@@ -646,7 +647,8 @@ static int usb_msd_initfn_bot(USBDevice *dev)
 
     usb_desc_create_serial(dev);
     usb_desc_init(dev);
-    scsi_bus_new(&s->bus, &s->dev.qdev, &usb_msd_scsi_info_bot, NULL);
+    scsi_bus_new(&s->bus, sizeof(s->bus), DEVICE(dev),
+                 &usb_msd_scsi_info_bot, NULL);
     s->bus.qbus.allow_hotplug = 0;
     usb_msd_handle_reset(dev);
 
diff --git a/hw/usb/dev-uas.c b/hw/usb/dev-uas.c
index 63ad12ea6b..1569d6e2ef 100644
--- a/hw/usb/dev-uas.c
+++ b/hw/usb/dev-uas.c
@@ -888,7 +888,8 @@ static int usb_uas_init(USBDevice *dev)
     QTAILQ_INIT(&uas->requests);
     uas->status_bh = qemu_bh_new(usb_uas_send_status_bh, uas);
 
-    scsi_bus_new(&uas->bus, &uas->dev.qdev, &usb_uas_scsi_info, NULL);
+    scsi_bus_new(&uas->bus, sizeof(uas->bus), DEVICE(dev),
+                 &usb_uas_scsi_info, NULL);
 
     return 0;
 }
diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
index e5523d54e0..137e200202 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 f91aa5580b..66bc61ae1e 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 39a25a72e1..35f0878409 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 578b949c92..becc7faec1 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 be6b86e2ba..d5c6588053 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/hw/virtio/virtio-mmio.c b/hw/virtio/virtio-mmio.c
index 4bd29533f3..29cf284d12 100644
--- a/hw/virtio/virtio-mmio.c
+++ b/hw/virtio/virtio-mmio.c
@@ -89,7 +89,8 @@ typedef struct {
     VirtioBusState bus;
 } VirtIOMMIOProxy;
 
-static void virtio_mmio_bus_new(VirtioBusState *bus, VirtIOMMIOProxy *dev);
+static void virtio_mmio_bus_new(VirtioBusState *bus, size_t bus_size,
+                                VirtIOMMIOProxy *dev);
 
 static uint64_t virtio_mmio_read(void *opaque, hwaddr offset, unsigned size)
 {
@@ -360,7 +361,7 @@ static void virtio_mmio_realizefn(DeviceState *d, Error **errp)
     VirtIOMMIOProxy *proxy = VIRTIO_MMIO(d);
     SysBusDevice *sbd = SYS_BUS_DEVICE(d);
 
-    virtio_mmio_bus_new(&proxy->bus, proxy);
+    virtio_mmio_bus_new(&proxy->bus, sizeof(proxy->bus), proxy);
     sysbus_init_irq(sbd, &proxy->irq);
     memory_region_init_io(&proxy->iomem, OBJECT(d), &virtio_mem_ops, proxy,
                           TYPE_VIRTIO_MMIO, 0x200);
@@ -385,12 +386,13 @@ static const TypeInfo virtio_mmio_info = {
 
 /* virtio-mmio-bus. */
 
-static void virtio_mmio_bus_new(VirtioBusState *bus, VirtIOMMIOProxy *dev)
+static void virtio_mmio_bus_new(VirtioBusState *bus, size_t bus_size,
+                                VirtIOMMIOProxy *dev)
 {
     DeviceState *qdev = DEVICE(dev);
     BusState *qbus;
 
-    qbus_create_inplace((BusState *)bus, TYPE_VIRTIO_MMIO_BUS, qdev, NULL);
+    qbus_create_inplace(bus, bus_size, TYPE_VIRTIO_MMIO_BUS, qdev, NULL);
     qbus = BUS(bus);
     qbus->allow_hotplug = 0;
 }
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index f2c489b66c..14fd65e374 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -92,7 +92,8 @@
 /* HACK for virtio to determine if it's running a big endian guest */
 bool virtio_is_big_endian(void);
 
-static void virtio_pci_bus_new(VirtioBusState *bus, VirtIOPCIProxy *dev);
+static void virtio_pci_bus_new(VirtioBusState *bus, size_t bus_size,
+                               VirtIOPCIProxy *dev);
 
 /* virtio device */
 /* DeviceState to VirtIOPCIProxy. For use off data-path. TODO: use QOM. */
@@ -918,7 +919,7 @@ static void virtio_9p_pci_class_init(ObjectClass *klass, void *data)
 static void virtio_9p_pci_instance_init(Object *obj)
 {
     V9fsPCIState *dev = VIRTIO_9P_PCI(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_9P);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_9P);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 }
 
@@ -986,7 +987,7 @@ static int virtio_pci_init(PCIDevice *pci_dev)
 {
     VirtIOPCIProxy *dev = VIRTIO_PCI(pci_dev);
     VirtioPCIClass *k = VIRTIO_PCI_GET_CLASS(pci_dev);
-    virtio_pci_bus_new(&dev->bus, dev);
+    virtio_pci_bus_new(&dev->bus, sizeof(dev->bus), dev);
     if (k->init != NULL) {
         return k->init(dev);
     }
@@ -1078,7 +1079,7 @@ static void virtio_blk_pci_class_init(ObjectClass *klass, void *data)
 static void virtio_blk_pci_instance_init(Object *obj)
 {
     VirtIOBlkPCI *dev = VIRTIO_BLK_PCI(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_BLK);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_BLK);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 }
 
@@ -1148,7 +1149,7 @@ static void virtio_scsi_pci_class_init(ObjectClass *klass, void *data)
 static void virtio_scsi_pci_instance_init(Object *obj)
 {
     VirtIOSCSIPCI *dev = VIRTIO_SCSI_PCI(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_SCSI);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_SCSI);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 }
 
@@ -1205,7 +1206,7 @@ static void vhost_scsi_pci_class_init(ObjectClass *klass, void *data)
 static void vhost_scsi_pci_instance_init(Object *obj)
 {
     VHostSCSIPCI *dev = VHOST_SCSI_PCI(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VHOST_SCSI);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VHOST_SCSI);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 }
 
@@ -1286,7 +1287,7 @@ static void virtio_balloon_pci_class_init(ObjectClass *klass, void *data)
 static void virtio_balloon_pci_instance_init(Object *obj)
 {
     VirtIOBalloonPCI *dev = VIRTIO_BALLOON_PCI(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_BALLOON);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_BALLOON);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 
     object_property_add(obj, "guest-stats", "guest statistics",
@@ -1372,7 +1373,7 @@ static void virtio_serial_pci_class_init(ObjectClass *klass, void *data)
 static void virtio_serial_pci_instance_init(Object *obj)
 {
     VirtIOSerialPCI *dev = VIRTIO_SERIAL_PCI(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_SERIAL);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_SERIAL);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 }
 
@@ -1431,7 +1432,7 @@ static void virtio_net_pci_class_init(ObjectClass *klass, void *data)
 static void virtio_net_pci_instance_init(Object *obj)
 {
     VirtIONetPCI *dev = VIRTIO_NET_PCI(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_NET);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_NET);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 }
 
@@ -1487,7 +1488,7 @@ static void virtio_rng_pci_class_init(ObjectClass *klass, void *data)
 static void virtio_rng_initfn(Object *obj)
 {
     VirtIORngPCI *dev = VIRTIO_RNG_PCI(obj);
-    object_initialize(OBJECT(&dev->vdev), TYPE_VIRTIO_RNG);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_RNG);
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
     object_property_add_link(obj, "rng", TYPE_RNG_BACKEND,
                              (Object **)&dev->vdev.conf.rng, NULL);
@@ -1504,13 +1505,14 @@ static const TypeInfo virtio_rng_pci_info = {
 
 /* virtio-pci-bus */
 
-static void virtio_pci_bus_new(VirtioBusState *bus, VirtIOPCIProxy *dev)
+static void virtio_pci_bus_new(VirtioBusState *bus, size_t bus_size,
+                               VirtIOPCIProxy *dev)
 {
     DeviceState *qdev = DEVICE(dev);
     BusState *qbus;
     char virtio_bus_name[] = "virtio-bus";
 
-    qbus_create_inplace((BusState *)bus, TYPE_VIRTIO_PCI_BUS, qdev,
+    qbus_create_inplace(bus, bus_size, TYPE_VIRTIO_PCI_BUS, qdev,
                         virtio_bus_name);
     qbus = BUS(bus);
     qbus->allow_hotplug = 1;
diff --git a/include/hw/isa/isa.h b/include/hw/isa/isa.h
index 495bcf3a08..fa45a5b094 100644
--- a/include/hw/isa/isa.h
+++ b/include/hw/isa/isa.h
@@ -78,7 +78,7 @@ void isa_register_ioport(ISADevice *dev, MemoryRegion *io, uint16_t start);
  * @dev: the ISADevice against which these are registered; may be NULL.
  * @start: the base I/O port against which the portio->offset is applied.
  * @portio: the ports, sorted by offset.
- * @opaque: passed into the old_portio callbacks.
+ * @opaque: passed into the portio callbacks.
  * @name: passed into memory_region_init_io.
  */
 void isa_register_portio_list(ISADevice *dev, uint16_t start,
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index ccec2bac31..051b6edcb9 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -348,7 +348,7 @@ typedef int (*pci_hotplug_fn)(DeviceState *qdev, PCIDevice *pci_dev,
 
 bool pci_bus_is_express(PCIBus *bus);
 bool pci_bus_is_root(PCIBus *bus);
-void pci_bus_new_inplace(PCIBus *bus, DeviceState *parent,
+void pci_bus_new_inplace(PCIBus *bus, size_t bus_size, DeviceState *parent,
                          const char *name,
                          MemoryRegion *address_space_mem,
                          MemoryRegion *address_space_io,
diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
index 46972f4961..a62f231eb9 100644
--- a/include/hw/qdev-core.h
+++ b/include/hw/qdev-core.h
@@ -264,7 +264,7 @@ DeviceState *qdev_find_recursive(BusState *bus, const char *id);
 typedef int (qbus_walkerfn)(BusState *bus, void *opaque);
 typedef int (qdev_walkerfn)(DeviceState *dev, void *opaque);
 
-void qbus_create_inplace(void *bus, const char *typename,
+void qbus_create_inplace(void *bus, size_t size, const char *typename,
                          DeviceState *parent, const char *name);
 BusState *qbus_create(const char *typename, DeviceState *parent, const char *name);
 /* Returns > 0 if either devfn or busfn skip walk somewhere in cursion,
diff --git a/include/hw/scsi/scsi.h b/include/hw/scsi/scsi.h
index 87865313eb..1b6651054a 100644
--- a/include/hw/scsi/scsi.h
+++ b/include/hw/scsi/scsi.h
@@ -152,8 +152,8 @@ struct SCSIBus {
     const SCSIBusInfo *info;
 };
 
-void scsi_bus_new(SCSIBus *bus, DeviceState *host, const SCSIBusInfo *info,
-                  const char *bus_name);
+void scsi_bus_new(SCSIBus *bus, size_t bus_size, DeviceState *host,
+                  const SCSIBusInfo *info, const char *bus_name);
 
 static inline SCSIBus *scsi_bus_from_device(SCSIDevice *d)
 {
diff --git a/include/hw/usb.h b/include/hw/usb.h
index 901b0da8b0..1b8acba6f6 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,
diff --git a/include/qom/object.h b/include/qom/object.h
index 9b69065b7a..1a7b71aba5 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -249,7 +249,7 @@ typedef struct InterfaceInfo InterfaceInfo;
  *     MyClass parent_class;
  *
  *     MyDoSomething parent_do_something;
- * } MyClass;
+ * } DerivedClass;
  *
  * static void derived_do_something(MyState *obj)
  * {
@@ -585,25 +585,27 @@ Object *object_new_with_type(Type type);
 
 /**
  * object_initialize_with_type:
- * @obj: A pointer to the memory to be used for the object.
+ * @data: A pointer to the memory to be used for the object.
+ * @size: The maximum size available at @data for the object.
  * @type: The type of the object to instantiate.
  *
  * This function will initialize an object.  The memory for the object should
  * have already been allocated.  The returned object has a reference count of 1,
  * and will be finalized when the last reference is dropped.
  */
-void object_initialize_with_type(void *data, Type type);
+void object_initialize_with_type(void *data, size_t size, Type type);
 
 /**
  * object_initialize:
  * @obj: A pointer to the memory to be used for the object.
+ * @size: The maximum size available at @obj for the object.
  * @typename: The name of the type of the object to instantiate.
  *
  * This function will initialize an object.  The memory for the object should
  * have already been allocated.  The returned object has a reference count of 1,
  * and will be finalized when the last reference is dropped.
  */
-void object_initialize(void *obj, const char *typename);
+void object_initialize(void *obj, size_t size, const char *typename);
 
 /**
  * object_dynamic_cast:
diff --git a/qom/object.c b/qom/object.c
index 74fd241a02..e90e3827d9 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -311,7 +311,7 @@ static void object_post_init_with_type(Object *obj, TypeImpl *ti)
     }
 }
 
-void object_initialize_with_type(void *data, TypeImpl *type)
+void object_initialize_with_type(void *data, size_t size, TypeImpl *type)
 {
     Object *obj = data;
 
@@ -320,6 +320,7 @@ void object_initialize_with_type(void *data, TypeImpl *type)
 
     g_assert(type->instance_size >= sizeof(Object));
     g_assert(type->abstract == false);
+    g_assert(size >= type->instance_size);
 
     memset(obj, 0, type->instance_size);
     obj->class = type->class;
@@ -329,11 +330,11 @@ void object_initialize_with_type(void *data, TypeImpl *type)
     object_post_init_with_type(obj, type);
 }
 
-void object_initialize(void *data, const char *typename)
+void object_initialize(void *data, size_t size, const char *typename)
 {
     TypeImpl *type = type_get_by_name(typename);
 
-    object_initialize_with_type(data, type);
+    object_initialize_with_type(data, size, type);
 }
 
 static inline bool object_property_is_child(ObjectProperty *prop)
@@ -424,7 +425,7 @@ Object *object_new_with_type(Type type)
     type_initialize(type);
 
     obj = g_malloc(type->instance_size);
-    object_initialize_with_type(obj, type);
+    object_initialize_with_type(obj, type->instance_size, type);
     obj->free = g_free;
 
     return obj;