Merge remote-tracking branch 'afaerber/tags/qom-devices-for-anthony' into staging

QOM infrastructure fixes and device conversions

* QOM interface fixes and unit test
* Device no_user sanitization and documentation
* Device error reporting improvement
* Conversion of APIC, ICC, IOAPIC to QOM realization model

# gpg: Signature made Tue 24 Dec 2013 09:04:05 AM PST using RSA key ID 3E7E013F
# gpg: Good signature from "Andreas Färber <afaerber@suse.de>"
# gpg:                 aka "Andreas Färber <afaerber@suse.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 174F 0347 1BCC 221A 6175  6F96 FA2E D12D 3E7E 013F

* afaerber/tags/qom-devices-for-anthony: (24 commits)
  qdev-monitor: Improve error message for -device nonexistant
  ioapic: QOM'ify ioapic
  ioapic: Cleanup for QOM'ification
  icc_bus: QOM'ify ICC
  apic: QOM'ify APIC
  apic: Cleanup for QOM'ification
  qdev: Drop misleading qbus_free() function
  qom: Detect bad reentrance during object_class_foreach()
  tests: Test QOM interface casting
  qom: Do not register interface "types" in the type table and fix names
  qom: Split out object and class caches
  qdev: Document that pointer properties kill device_add
  hw: cannot_instantiate_with_device_add_yet due to pointer props
  qdev-monitor: Avoid device_add crashing on non-device driver name
  qdev: Do not let the user try to device_add when it cannot work
  isa: Clean up use of cannot_instantiate_with_device_add_yet
  vt82c686: Clean up use of cannot_instantiate_with_device_add_yet
  piix3 piix4: Clean up use of cannot_instantiate_with_device_add_yet
  ich9: Document why cannot_instantiate_with_device_add_yet
  pci-host: Consistently set cannot_instantiate_with_device_add_yet
  ...

73 files changed, 298 insertions, 153 deletions

diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
index 93849c8d36..9e8a89c233 100644
--- a/hw/acpi/piix4.c
+++ b/hw/acpi/piix4.c
@@ -544,9 +544,13 @@ static void piix4_pm_class_init(ObjectClass *klass, void *data)
     k->revision = 0x03;
     k->class_id = PCI_CLASS_BRIDGE_OTHER;
     dc->desc = "PM";
-    dc->no_user = 1;
     dc->vmsd = &vmstate_acpi;
     dc->props = piix4_pm_properties;
+    /*
+     * Reason: part of PIIX4 southbridge, needs to be wired up,
+     * e.g. by mips_malta_init()
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo piix4_pm_info = {
diff --git a/hw/alpha/typhoon.c b/hw/alpha/typhoon.c
index 59e1bb8388..71a5a37fdc 100644
--- a/hw/alpha/typhoon.c
+++ b/hw/alpha/typhoon.c
@@ -934,11 +934,9 @@ static int typhoon_pcihost_init(SysBusDevice *dev)
 
 static void typhoon_pcihost_class_init(ObjectClass *klass, void *data)
 {
-    DeviceClass *dc = DEVICE_CLASS(klass);
     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 
     k->init = typhoon_pcihost_init;
-    dc->no_user = 1;
 }
 
 static const TypeInfo typhoon_pcihost_info = {
diff --git a/hw/arm/versatilepb.c b/hw/arm/versatilepb.c
index f7e8b7e8fa..aef2bde0c4 100644
--- a/hw/arm/versatilepb.c
+++ b/hw/arm/versatilepb.c
@@ -390,7 +390,6 @@ static void vpb_sic_class_init(ObjectClass *klass, void *data)
     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 
     k->init = vpb_sic_init;
-    dc->no_user = 1;
     dc->vmsd = &vmstate_vpb_sic;
 }
 
diff --git a/hw/audio/marvell_88w8618.c b/hw/audio/marvell_88w8618.c
index 97194ce7ad..cdce238f55 100644
--- a/hw/audio/marvell_88w8618.c
+++ b/hw/audio/marvell_88w8618.c
@@ -288,6 +288,8 @@ static void mv88w8618_audio_class_init(ObjectClass *klass, void *data)
     dc->reset = mv88w8618_audio_reset;
     dc->vmsd = &mv88w8618_audio_vmsd;
     dc->props = mv88w8618_audio_properties;
+    /* Reason: pointer property "wm8750" */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo mv88w8618_audio_info = {
diff --git a/hw/audio/pcspk.c b/hw/audio/pcspk.c
index 9004ce3d1f..f980d66b2f 100644
--- a/hw/audio/pcspk.c
+++ b/hw/audio/pcspk.c
@@ -192,8 +192,9 @@ static void pcspk_class_initfn(ObjectClass *klass, void *data)
 
     dc->realize = pcspk_realizefn;
     set_bit(DEVICE_CATEGORY_SOUND, dc->categories);
-    dc->no_user = 1;
     dc->props = pcspk_properties;
+    /* Reason: pointer property "pit", realize sets global pcspk_state */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo pcspk_info = {
diff --git a/hw/audio/pl041.c b/hw/audio/pl041.c
index 5393b520b7..ed82be54e8 100644
--- a/hw/audio/pl041.c
+++ b/hw/audio/pl041.c
@@ -632,7 +632,6 @@ static void pl041_device_class_init(ObjectClass *klass, void *data)
 
     k->init = pl041_init;
     set_bit(DEVICE_CATEGORY_SOUND, dc->categories);
-    dc->no_user = 1;
     dc->reset = pl041_device_reset;
     dc->vmsd = &vmstate_pl041;
     dc->props = pl041_device_properties;
diff --git a/hw/block/fdc.c b/hw/block/fdc.c
index c5a6c21215..592b58f9b5 100644
--- a/hw/block/fdc.c
+++ b/hw/block/fdc.c
@@ -2234,7 +2234,6 @@ static void isabus_fdc_class_init(ObjectClass *klass, void *data)
 
     dc->realize = isabus_fdc_realize;
     dc->fw_name = "fdc";
-    dc->no_user = 1;
     dc->reset = fdctrl_external_reset_isa;
     dc->vmsd = &vmstate_isa_fdc;
     dc->props = isa_fdc_properties;
diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index e374a9399f..bbd780aad1 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -481,11 +481,6 @@ BusState *qbus_create(const char *typename, DeviceState *parent, const char *nam
     return bus;
 }
 
-void qbus_free(BusState *bus)
-{
-    object_unparent(OBJECT(bus));
-}
-
 static char *bus_get_fw_dev_path(BusState *bus, DeviceState *dev)
 {
     BusClass *bc = BUS_GET_CLASS(bus);
@@ -794,7 +789,7 @@ static void device_unparent(Object *obj)
 
     while (dev->num_child_bus) {
         bus = QLIST_FIRST(&dev->child_bus);
-        qbus_free(bus);
+        object_unparent(OBJECT(bus));
     }
     if (dev->realized) {
         object_property_set_bool(obj, false, "realized", NULL);
diff --git a/hw/core/sysbus.c b/hw/core/sysbus.c
index 146f50aa15..f4e760d6eb 100644
--- a/hw/core/sysbus.c
+++ b/hw/core/sysbus.c
@@ -257,6 +257,13 @@ static void sysbus_device_class_init(ObjectClass *klass, void *data)
     DeviceClass *k = DEVICE_CLASS(klass);
     k->init = sysbus_device_init;
     k->bus_type = TYPE_SYSTEM_BUS;
+    /*
+     * device_add plugs devices into suitable bus.  For "real" buses,
+     * that actually connects the device.  For sysbus, the connections
+     * need to be made separately, and device_add can't do that.  The
+     * device would be left unconnected, and could not possibly work.
+     */
+    k->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo sysbus_device_type_info = {
diff --git a/hw/cpu/icc_bus.c b/hw/cpu/icc_bus.c
index 9a4ea7e2df..7f44c59b25 100644
--- a/hw/cpu/icc_bus.c
+++ b/hw/cpu/icc_bus.c
@@ -43,15 +43,13 @@ static const TypeInfo icc_bus_info = {
 
 static void icc_device_realize(DeviceState *dev, Error **errp)
 {
-    ICCDevice *id = ICC_DEVICE(dev);
-    ICCDeviceClass *idc = ICC_DEVICE_GET_CLASS(id);
-
-    if (idc->init) {
-        if (idc->init(id) < 0) {
-            error_setg(errp, "%s initialization failed.",
-                       object_get_typename(OBJECT(dev)));
-        }
+    ICCDeviceClass *idc = ICC_DEVICE_GET_CLASS(dev);
+
+    /* convert to QOM */
+    if (idc->realize) {
+        idc->realize(dev, errp);
     }
+
 }
 
 static void icc_device_class_init(ObjectClass *oc, void *data)
diff --git a/hw/display/pl110.c b/hw/display/pl110.c
index 790e5108ed..ab689e9aae 100644
--- a/hw/display/pl110.c
+++ b/hw/display/pl110.c
@@ -496,7 +496,6 @@ static void pl110_class_init(ObjectClass *klass, void *data)
 
     k->init = pl110_initfn;
     set_bit(DEVICE_CATEGORY_DISPLAY, dc->categories);
-    dc->no_user = 1;
     dc->vmsd = &vmstate_pl110;
 }
 
diff --git a/hw/dma/pl080.c b/hw/dma/pl080.c
index 35b90155a2..cb7bda9803 100644
--- a/hw/dma/pl080.c
+++ b/hw/dma/pl080.c
@@ -381,7 +381,6 @@ static void pl080_class_init(ObjectClass *oc, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(oc);
 
-    dc->no_user = 1;
     dc->vmsd = &vmstate_pl080;
 }
 
diff --git a/hw/dma/sparc32_dma.c b/hw/dma/sparc32_dma.c
index 2a92ffb82e..eac338f1bc 100644
--- a/hw/dma/sparc32_dma.c
+++ b/hw/dma/sparc32_dma.c
@@ -304,6 +304,8 @@ static void sparc32_dma_class_init(ObjectClass *klass, void *data)
     dc->reset = dma_reset;
     dc->vmsd = &vmstate_dma;
     dc->props = sparc32_dma_properties;
+    /* Reason: pointer property "iommu_opaque" */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo sparc32_dma_info = {
diff --git a/hw/gpio/omap_gpio.c b/hw/gpio/omap_gpio.c
index b8f572bb70..938782a45d 100644
--- a/hw/gpio/omap_gpio.c
+++ b/hw/gpio/omap_gpio.c
@@ -759,6 +759,8 @@ static void omap_gpio_class_init(ObjectClass *klass, void *data)
     k->init = omap_gpio_init;
     dc->reset = omap_gpif_reset;
     dc->props = omap_gpio_properties;
+    /* Reason: pointer property "clk" */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo omap_gpio_info = {
@@ -788,6 +790,8 @@ static void omap2_gpio_class_init(ObjectClass *klass, void *data)
     k->init = omap2_gpio_init;
     dc->reset = omap2_gpif_reset;
     dc->props = omap2_gpio_properties;
+    /* Reason: pointer properties "iclk", "fclk0", ..., "fclk5" */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo omap2_gpio_info = {
diff --git a/hw/i2c/omap_i2c.c b/hw/i2c/omap_i2c.c
index f528b2b38e..2d8e2b7839 100644
--- a/hw/i2c/omap_i2c.c
+++ b/hw/i2c/omap_i2c.c
@@ -475,6 +475,8 @@ static void omap_i2c_class_init(ObjectClass *klass, void *data)
     k->init = omap_i2c_init;
     dc->props = omap_i2c_properties;
     dc->reset = omap_i2c_reset;
+    /* Reason: pointer properties "iclk", "fclk" */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo omap_i2c_info = {
diff --git a/hw/i2c/smbus_eeprom.c b/hw/i2c/smbus_eeprom.c
index 0154283762..0218f8a0eb 100644
--- a/hw/i2c/smbus_eeprom.c
+++ b/hw/i2c/smbus_eeprom.c
@@ -121,6 +121,8 @@ static void smbus_eeprom_class_initfn(ObjectClass *klass, void *data)
     sc->write_data = eeprom_write_data;
     sc->read_data = eeprom_read_data;
     dc->props = smbus_eeprom_properties;
+    /* Reason: pointer property "data" */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo smbus_eeprom_info = {
diff --git a/hw/i2c/smbus_ich9.c b/hw/i2c/smbus_ich9.c
index ca229789f4..8d47eaffc8 100644
--- a/hw/i2c/smbus_ich9.c
+++ b/hw/i2c/smbus_ich9.c
@@ -97,11 +97,15 @@ static void ich9_smb_class_init(ObjectClass *klass, void *data)
     k->device_id = PCI_DEVICE_ID_INTEL_ICH9_6;
     k->revision = ICH9_A2_SMB_REVISION;
     k->class_id = PCI_CLASS_SERIAL_SMBUS;
-    dc->no_user = 1;
     dc->vmsd = &vmstate_ich9_smbus;
     dc->desc = "ICH9 SMBUS Bridge";
     k->init = ich9_smbus_initfn;
     k->config_write = ich9_smbus_write_config;
+    /*
+     * Reason: part of ICH9 southbridge, needs to be wired up by
+     * pc_q35_init()
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 i2c_bus *ich9_smb_init(PCIBus *bus, int devfn, uint32_t smb_io_base)
diff --git a/hw/i386/kvm/apic.c b/hw/i386/kvm/apic.c
index 5609063120..e873b509a5 100644
--- a/hw/i386/kvm/apic.c
+++ b/hw/i386/kvm/apic.c
@@ -25,9 +25,9 @@ static inline uint32_t kvm_apic_get_reg(struct kvm_lapic_state *kapic,
     return *((uint32_t *)(kapic->regs + (reg_id << 4)));
 }
 
-void kvm_put_apic_state(DeviceState *d, struct kvm_lapic_state *kapic)
+void kvm_put_apic_state(DeviceState *dev, struct kvm_lapic_state *kapic)
 {
-    APICCommonState *s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+    APICCommonState *s = APIC_COMMON(dev);
     int i;
 
     memset(kapic, 0, sizeof(*kapic));
@@ -51,9 +51,9 @@ void kvm_put_apic_state(DeviceState *d, struct kvm_lapic_state *kapic)
     kvm_apic_set_reg(kapic, 0x3e, s->divide_conf);
 }
 
-void kvm_get_apic_state(DeviceState *d, struct kvm_lapic_state *kapic)
+void kvm_get_apic_state(DeviceState *dev, struct kvm_lapic_state *kapic)
 {
-    APICCommonState *s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+    APICCommonState *s = APIC_COMMON(dev);
     int i, v;
 
     s->id = kvm_apic_get_reg(kapic, 0x2) >> 24;
@@ -171,8 +171,10 @@ static const MemoryRegionOps kvm_apic_io_ops = {
     .endianness = DEVICE_NATIVE_ENDIAN,
 };
 
-static void kvm_apic_init(APICCommonState *s)
+static void kvm_apic_realize(DeviceState *dev, Error **errp)
 {
+    APICCommonState *s = APIC_COMMON(dev);
+
     memory_region_init_io(&s->io_memory, NULL, &kvm_apic_io_ops, s, "kvm-apic-msi",
                           APIC_SPACE_SIZE);
 
@@ -185,7 +187,7 @@ static void kvm_apic_class_init(ObjectClass *klass, void *data)
 {
     APICCommonClass *k = APIC_COMMON_CLASS(klass);
 
-    k->init = kvm_apic_init;
+    k->realize = kvm_apic_realize;
     k->set_base = kvm_apic_set_base;
     k->set_tpr = kvm_apic_set_tpr;
     k->get_tpr = kvm_apic_get_tpr;
diff --git a/hw/i386/kvm/clock.c b/hw/i386/kvm/clock.c
index 383938d1bc..892aa025f4 100644
--- a/hw/i386/kvm/clock.c
+++ b/hw/i386/kvm/clock.c
@@ -114,7 +114,6 @@ static void kvmclock_class_init(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = kvmclock_realize;
-    dc->no_user = 1;
     dc->vmsd = &kvmclock_vmsd;
 }
 
diff --git a/hw/i386/kvm/ioapic.c b/hw/i386/kvm/ioapic.c
index f11a540825..d2a6c4cf60 100644
--- a/hw/i386/kvm/ioapic.c
+++ b/hw/i386/kvm/ioapic.c
@@ -127,11 +127,13 @@ static void kvm_ioapic_set_irq(void *opaque, int irq, int level)
     apic_report_irq_delivered(delivered);
 }
 
-static void kvm_ioapic_init(IOAPICCommonState *s, int instance_no)
+static void kvm_ioapic_realize(DeviceState *dev, Error **errp)
 {
+    IOAPICCommonState *s = IOAPIC_COMMON(dev);
+
     memory_region_init_reservation(&s->io_memory, NULL, "kvm-ioapic", 0x1000);
 
-    qdev_init_gpio_in(DEVICE(s), kvm_ioapic_set_irq, IOAPIC_NUM_PINS);
+    qdev_init_gpio_in(dev, kvm_ioapic_set_irq, IOAPIC_NUM_PINS);
 }
 
 static Property kvm_ioapic_properties[] = {
@@ -144,7 +146,7 @@ static void kvm_ioapic_class_init(ObjectClass *klass, void *data)
     IOAPICCommonClass *k = IOAPIC_COMMON_CLASS(klass);
     DeviceClass *dc = DEVICE_CLASS(klass);
 
-    k->init      = kvm_ioapic_init;
+    k->realize   = kvm_ioapic_realize;
     k->pre_save  = kvm_ioapic_get;
     k->post_load = kvm_ioapic_put;
     dc->reset    = kvm_ioapic_reset;
diff --git a/hw/i386/kvmvapic.c b/hw/i386/kvmvapic.c
index 2d876009fc..44ee62a233 100644
--- a/hw/i386/kvmvapic.c
+++ b/hw/i386/kvmvapic.c
@@ -827,7 +827,6 @@ static void vapic_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
 
-    dc->no_user = 1;
     dc->reset   = vapic_reset;
     dc->vmsd    = &vmstate_vapic;
     dc->realize = vapic_realize;
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 3cd8f383f3..e9831ca411 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -547,10 +547,15 @@ static void port92_class_initfn(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
 
-    dc->no_user = 1;
     dc->realize = port92_realizefn;
     dc->reset = port92_reset;
     dc->vmsd = &vmstate_port92_isa;
+    /*
+     * Reason: unlike ordinary ISA devices, this one needs additional
+     * wiring: its A20 output line needs to be wired up by
+     * port92_init().
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo port92_info = {
diff --git a/hw/ide/piix.c b/hw/ide/piix.c
index ab36749417..9b5960b44e 100644
--- a/hw/ide/piix.c
+++ b/hw/ide/piix.c
@@ -248,7 +248,6 @@ static void piix3_ide_class_init(ObjectClass *klass, void *data)
     k->device_id = PCI_DEVICE_ID_INTEL_82371SB_1;
     k->class_id = PCI_CLASS_STORAGE_IDE;
     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
-    dc->no_user = 1;
 }
 
 static const TypeInfo piix3_ide_info = {
@@ -267,7 +266,6 @@ static void piix3_ide_xen_class_init(ObjectClass *klass, void *data)
     k->device_id = PCI_DEVICE_ID_INTEL_82371SB_1;
     k->class_id = PCI_CLASS_STORAGE_IDE;
     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
-    dc->no_user = 1;
     dc->unplug = pci_piix3_xen_ide_unplug;
 }
 
@@ -289,7 +287,6 @@ static void piix4_ide_class_init(ObjectClass *klass, void *data)
     k->device_id = PCI_DEVICE_ID_INTEL_82371AB;
     k->class_id = PCI_CLASS_STORAGE_IDE;
     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
-    dc->no_user = 1;
 }
 
 static const TypeInfo piix4_ide_info = {
diff --git a/hw/ide/via.c b/hw/ide/via.c
index 99468c773e..198123b026 100644
--- a/hw/ide/via.c
+++ b/hw/ide/via.c
@@ -225,7 +225,6 @@ static void via_ide_class_init(ObjectClass *klass, void *data)
     k->revision = 0x06;
     k->class_id = PCI_CLASS_STORAGE_IDE;
     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
-    dc->no_user = 1;
 }
 
 static const TypeInfo via_ide_info = {
diff --git a/hw/input/pckbd.c b/hw/input/pckbd.c
index ce86237cf3..655b8c5011 100644
--- a/hw/input/pckbd.c
+++ b/hw/input/pckbd.c
@@ -522,7 +522,6 @@ static void i8042_class_initfn(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = i8042_realizefn;
-    dc->no_user = 1;
     dc->vmsd = &vmstate_kbd_isa;
 }
 
diff --git a/hw/input/vmmouse.c b/hw/input/vmmouse.c
index abd032b794..6a5053352a 100644
--- a/hw/input/vmmouse.c
+++ b/hw/input/vmmouse.c
@@ -282,10 +282,11 @@ static void vmmouse_class_initfn(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = vmmouse_realizefn;
-    dc->no_user = 1;
     dc->reset = vmmouse_reset;
     dc->vmsd = &vmstate_vmmouse;
     dc->props = vmmouse_properties;
+    /* Reason: pointer property "ps2_mouse" */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo vmmouse_info = {
diff --git a/hw/intc/apic.c b/hw/intc/apic.c
index a913186ed0..3d3deb6298 100644
--- a/hw/intc/apic.c
+++ b/hw/intc/apic.c
@@ -171,9 +171,9 @@ static void apic_local_deliver(APICCommonState *s, int vector)
     }
 }
 
-void apic_deliver_pic_intr(DeviceState *d, int level)
+void apic_deliver_pic_intr(DeviceState *dev, int level)
 {
-    APICCommonState *s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+    APICCommonState *s = APIC_COMMON(dev);
 
     if (level) {
         apic_local_deliver(s, APIC_LVT_LINT0);
@@ -376,9 +376,9 @@ static void apic_update_irq(APICCommonState *s)
     }
 }
 
-void apic_poll_irq(DeviceState *d)
+void apic_poll_irq(DeviceState *dev)
 {
-    APICCommonState *s = APIC_COMMON(d);
+    APICCommonState *s = APIC_COMMON(dev);
 
     apic_sync_vapic(s, SYNC_FROM_VAPIC);
     apic_update_irq(s);
@@ -482,9 +482,9 @@ static void apic_startup(APICCommonState *s, int vector_num)
     cpu_interrupt(CPU(s->cpu), CPU_INTERRUPT_SIPI);
 }
 
-void apic_sipi(DeviceState *d)
+void apic_sipi(DeviceState *dev)
 {
-    APICCommonState *s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+    APICCommonState *s = APIC_COMMON(dev);
 
     cpu_reset_interrupt(CPU(s->cpu), CPU_INTERRUPT_SIPI);
 
@@ -494,11 +494,11 @@ void apic_sipi(DeviceState *d)
     s->wait_for_sipi = 0;
 }
 
-static void apic_deliver(DeviceState *d, uint8_t dest, uint8_t dest_mode,
+static void apic_deliver(DeviceState *dev, uint8_t dest, uint8_t dest_mode,
                          uint8_t delivery_mode, uint8_t vector_num,
                          uint8_t trigger_mode)
 {
-    APICCommonState *s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+    APICCommonState *s = APIC_COMMON(dev);
     uint32_t deliver_bitmask[MAX_APIC_WORDS];
     int dest_shorthand = (s->icr[0] >> 18) & 3;
     APICCommonState *apic_iter;
@@ -551,9 +551,9 @@ static bool apic_check_pic(APICCommonState *s)
     return true;
 }
 
-int apic_get_interrupt(DeviceState *d)
+int apic_get_interrupt(DeviceState *dev)
 {
-    APICCommonState *s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+    APICCommonState *s = APIC_COMMON(dev);
     int intno;
 
     /* if the APIC is installed or enabled, we let the 8259 handle the
@@ -585,9 +585,9 @@ int apic_get_interrupt(DeviceState *d)
     return intno;
 }
 
-int apic_accept_pic_intr(DeviceState *d)
+int apic_accept_pic_intr(DeviceState *dev)
 {
-    APICCommonState *s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+    APICCommonState *s = APIC_COMMON(dev);
     uint32_t lvt0;
 
     if (!s)
@@ -657,16 +657,16 @@ static void apic_mem_writew(void *opaque, hwaddr addr, uint32_t val)
 
 static uint32_t apic_mem_readl(void *opaque, hwaddr addr)
 {
-    DeviceState *d;
+    DeviceState *dev;
     APICCommonState *s;
     uint32_t val;
     int index;
 
-    d = cpu_get_current_apic();
-    if (!d) {
+    dev = cpu_get_current_apic();
+    if (!dev) {
         return 0;
     }
-    s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+    s = APIC_COMMON(dev);
 
     index = (addr >> 4) & 0xff;
     switch(index) {
@@ -752,7 +752,7 @@ static void apic_send_msi(hwaddr addr, uint32_t data)
 
 static void apic_mem_writel(void *opaque, hwaddr addr, uint32_t val)
 {
-    DeviceState *d;
+    DeviceState *dev;
     APICCommonState *s;
     int index = (addr >> 4) & 0xff;
     if (addr > 0xfff || !index) {
@@ -765,11 +765,11 @@ static void apic_mem_writel(void *opaque, hwaddr addr, uint32_t val)
         return;
     }
 
-    d = cpu_get_current_apic();
-    if (!d) {
+    dev = cpu_get_current_apic();
+    if (!dev) {
         return;
     }
-    s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+    s = APIC_COMMON(dev);
 
     trace_apic_mem_writel(addr, val);
 
@@ -810,7 +810,7 @@ static void apic_mem_writel(void *opaque, hwaddr addr, uint32_t val)
         break;
     case 0x30:
         s->icr[0] = val;
-        apic_deliver(d, (s->icr[1] >> 24) & 0xff, (s->icr[0] >> 11) & 1,
+        apic_deliver(dev, (s->icr[1] >> 24) & 0xff, (s->icr[0] >> 11) & 1,
                      (s->icr[0] >> 8) & 7, (s->icr[0] & 0xff),
                      (s->icr[0] >> 15) & 1);
         break;
@@ -871,8 +871,10 @@ static const MemoryRegionOps apic_io_ops = {
     .endianness = DEVICE_NATIVE_ENDIAN,
 };
 
-static void apic_init(APICCommonState *s)
+static void apic_realize(DeviceState *dev, Error **errp)
 {
+    APICCommonState *s = APIC_COMMON(dev);
+
     memory_region_init_io(&s->io_memory, OBJECT(s), &apic_io_ops, s, "apic-msi",
                           APIC_SPACE_SIZE);
 
@@ -886,7 +888,7 @@ static void apic_class_init(ObjectClass *klass, void *data)
 {
     APICCommonClass *k = APIC_COMMON_CLASS(klass);
 
-    k->init = apic_init;
+    k->realize = apic_realize;
     k->set_base = apic_set_base;
     k->set_tpr = apic_set_tpr;
     k->get_tpr = apic_get_tpr;
diff --git a/hw/intc/apic_common.c b/hw/intc/apic_common.c
index a0beb10863..c623fcc6d8 100644
--- a/hw/intc/apic_common.c
+++ b/hw/intc/apic_common.c
@@ -27,21 +27,21 @@
 static int apic_irq_delivered;
 bool apic_report_tpr_access;
 
-void cpu_set_apic_base(DeviceState *d, uint64_t val)
+void cpu_set_apic_base(DeviceState *dev, uint64_t val)
 {
     trace_cpu_set_apic_base(val);
 
-    if (d) {
-        APICCommonState *s = APIC_COMMON(d);
+    if (dev) {
+        APICCommonState *s = APIC_COMMON(dev);
         APICCommonClass *info = APIC_COMMON_GET_CLASS(s);
         info->set_base(s, val);
     }
 }
 
-uint64_t cpu_get_apic_base(DeviceState *d)
+uint64_t cpu_get_apic_base(DeviceState *dev)
 {
-    if (d) {
-        APICCommonState *s = APIC_COMMON(d);
+    if (dev) {
+        APICCommonState *s = APIC_COMMON(dev);
         trace_cpu_get_apic_base((uint64_t)s->apicbase);
         return s->apicbase;
     } else {
@@ -50,39 +50,39 @@ uint64_t cpu_get_apic_base(DeviceState *d)
     }
 }
 
-void cpu_set_apic_tpr(DeviceState *d, uint8_t val)
+void cpu_set_apic_tpr(DeviceState *dev, uint8_t val)
 {
     APICCommonState *s;
     APICCommonClass *info;
 
-    if (!d) {
+    if (!dev) {
         return;
     }
 
-    s = APIC_COMMON(d);
+    s = APIC_COMMON(dev);
     info = APIC_COMMON_GET_CLASS(s);
 
     info->set_tpr(s, val);
 }
 
-uint8_t cpu_get_apic_tpr(DeviceState *d)
+uint8_t cpu_get_apic_tpr(DeviceState *dev)
 {
     APICCommonState *s;
     APICCommonClass *info;
 
-    if (!d) {
+    if (!dev) {
         return 0;
     }
 
-    s = APIC_COMMON(d);
+    s = APIC_COMMON(dev);
     info = APIC_COMMON_GET_CLASS(s);
 
     return info->get_tpr(s);
 }
 
-void apic_enable_tpr_access_reporting(DeviceState *d, bool enable)
+void apic_enable_tpr_access_reporting(DeviceState *dev, bool enable)
 {
-    APICCommonState *s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+    APICCommonState *s = APIC_COMMON(dev);
     APICCommonClass *info = APIC_COMMON_GET_CLASS(s);
 
     apic_report_tpr_access = enable;
@@ -91,19 +91,19 @@ void apic_enable_tpr_access_reporting(DeviceState *d, bool enable)
     }
 }
 
-void apic_enable_vapic(DeviceState *d, hwaddr paddr)
+void apic_enable_vapic(DeviceState *dev, hwaddr paddr)
 {
-    APICCommonState *s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+    APICCommonState *s = APIC_COMMON(dev);
     APICCommonClass *info = APIC_COMMON_GET_CLASS(s);
 
     s->vapic_paddr = paddr;
     info->vapic_base_update(s);
 }
 
-void apic_handle_tpr_access_report(DeviceState *d, target_ulong ip,
+void apic_handle_tpr_access_report(DeviceState *dev, target_ulong ip,
                                    TPRAccess access)
 {
-    APICCommonState *s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+    APICCommonState *s = APIC_COMMON(dev);
 
     vapic_report_tpr_access(s->vapic, CPU(s->cpu), ip, access);
 }
@@ -129,9 +129,9 @@ int apic_get_irq_delivered(void)
     return apic_irq_delivered;
 }
 
-void apic_deliver_nmi(DeviceState *d)
+void apic_deliver_nmi(DeviceState *dev)
 {
-    APICCommonState *s = APIC_COMMON(d);
+    APICCommonState *s = APIC_COMMON(dev);
     APICCommonClass *info = APIC_COMMON_GET_CLASS(s);
 
     info->external_nmi(s);
@@ -170,9 +170,9 @@ bool apic_next_timer(APICCommonState *s, int64_t current_time)
     return true;
 }
 
-void apic_init_reset(DeviceState *d)
+void apic_init_reset(DeviceState *dev)
 {
-    APICCommonState *s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+    APICCommonState *s = APIC_COMMON(dev);
     int i;
 
     if (!s) {
@@ -203,19 +203,19 @@ void apic_init_reset(DeviceState *d)
     s->timer_expiry = -1;
 }
 
-void apic_designate_bsp(DeviceState *d)
+void apic_designate_bsp(DeviceState *dev)
 {
-    if (d == NULL) {
+    if (dev == NULL) {
         return;
     }
 
-    APICCommonState *s = APIC_COMMON(d);
+    APICCommonState *s = APIC_COMMON(dev);
     s->apicbase |= MSR_IA32_APICBASE_BSP;
 }
 
-static void apic_reset_common(DeviceState *d)
+static void apic_reset_common(DeviceState *dev)
 {
-    APICCommonState *s = DO_UPCAST(APICCommonState, busdev.qdev, d);
+    APICCommonState *s = APIC_COMMON(dev);
     APICCommonClass *info = APIC_COMMON_GET_CLASS(s);
     bool bsp;
 
@@ -226,7 +226,7 @@ static void apic_reset_common(DeviceState *d)
     s->vapic_paddr = 0;
     info->vapic_base_update(s);
 
-    apic_init_reset(d);
+    apic_init_reset(dev);
 
     if (bsp) {
         /*
@@ -284,7 +284,7 @@ static int apic_load_old(QEMUFile *f, void *opaque, int version_id)
     return 0;
 }
 
-static int apic_init_common(ICCDevice *dev)
+static void apic_common_realize(DeviceState *dev, Error **errp)
 {
     APICCommonState *s = APIC_COMMON(dev);
     APICCommonClass *info;
@@ -293,14 +293,16 @@ static int apic_init_common(ICCDevice *dev)
     static bool mmio_registered;
 
     if (apic_no >= MAX_APICS) {
-        return -1;
+        error_setg(errp, "%s initialization failed.",
+                   object_get_typename(OBJECT(dev)));
+        return;
     }
     s->idx = apic_no++;
 
     info = APIC_COMMON_GET_CLASS(s);
-    info->init(s);
+    info->realize(dev, errp);
     if (!mmio_registered) {
-        ICCBus *b = ICC_BUS(qdev_get_parent_bus(DEVICE(dev)));
+        ICCBus *b = ICC_BUS(qdev_get_parent_bus(dev));
         memory_region_add_subregion(b->apic_address_space, 0, &s->io_memory);
         mmio_registered = true;
     }
@@ -315,7 +317,6 @@ static int apic_init_common(ICCDevice *dev)
         info->enable_tpr_reporting(s, true);
     }
 
-    return 0;
 }
 
 static void apic_dispatch_pre_save(void *opaque)
@@ -386,9 +387,13 @@ static void apic_common_class_init(ObjectClass *klass, void *data)
 
     dc->vmsd = &vmstate_apic_common;
     dc->reset = apic_reset_common;
-    dc->no_user = 1;
     dc->props = apic_properties_common;
-    idc->init = apic_init_common;
+    idc->realize = apic_common_realize;
+    /*
+     * Reason: APIC and CPU need to be wired up by
+     * x86_cpu_apic_create()
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo apic_common_type = {
@@ -400,9 +405,9 @@ static const TypeInfo apic_common_type = {
     .abstract = true,
 };
 
-static void register_types(void)
+static void apic_common_register_types(void)
 {
     type_register_static(&apic_common_type);
 }
 
-type_init(register_types)
+type_init(apic_common_register_types)
diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c
index 6c5965093e..9409684ce8 100644
--- a/hw/intc/arm_gic.c
+++ b/hw/intc/arm_gic.c
@@ -709,7 +709,6 @@ static void arm_gic_class_init(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
     ARMGICClass *agc = ARM_GIC_CLASS(klass);
 
-    dc->no_user = 1;
     agc->parent_realize = dc->realize;
     dc->realize = arm_gic_realize;
 }
diff --git a/hw/intc/arm_gic_common.c b/hw/intc/arm_gic_common.c
index 710607b044..e4fc65028a 100644
--- a/hw/intc/arm_gic_common.c
+++ b/hw/intc/arm_gic_common.c
@@ -156,7 +156,6 @@ static void arm_gic_common_class_init(ObjectClass *klass, void *data)
     dc->realize = arm_gic_common_realize;
     dc->props = arm_gic_common_properties;
     dc->vmsd = &vmstate_gic;
-    dc->no_user = 1;
 }
 
 static const TypeInfo arm_gic_common_type = {
diff --git a/hw/intc/arm_gic_kvm.c b/hw/intc/arm_gic_kvm.c
index f71397542a..59a3da5a6b 100644
--- a/hw/intc/arm_gic_kvm.c
+++ b/hw/intc/arm_gic_kvm.c
@@ -150,7 +150,6 @@ static void kvm_arm_gic_class_init(ObjectClass *klass, void *data)
     kgc->parent_reset = dc->reset;
     dc->realize = kvm_arm_gic_realize;
     dc->reset = kvm_arm_gic_reset;
-    dc->no_user = 1;
 }
 
 static const TypeInfo kvm_arm_gic_info = {
diff --git a/hw/intc/etraxfs_pic.c b/hw/intc/etraxfs_pic.c
index e02da533cb..636262b49f 100644
--- a/hw/intc/etraxfs_pic.c
+++ b/hw/intc/etraxfs_pic.c
@@ -170,6 +170,10 @@ static void etraxfs_pic_class_init(ObjectClass *klass, void *data)
 
     k->init = etraxfs_pic_init;
     dc->props = etraxfs_pic_properties;
+    /*
+     * Note: pointer property "interrupt_vector" may remain null, thus
+     * no need for dc->cannot_instantiate_with_device_add_yet = true;
+     */
 }
 
 static const TypeInfo etraxfs_pic_info = {
diff --git a/hw/intc/grlib_irqmp.c b/hw/intc/grlib_irqmp.c
index 42e00bc4b8..d1813f76b6 100644
--- a/hw/intc/grlib_irqmp.c
+++ b/hw/intc/grlib_irqmp.c
@@ -355,6 +355,8 @@ static void grlib_irqmp_class_init(ObjectClass *klass, void *data)
     k->init = grlib_irqmp_init;
     dc->reset = grlib_irqmp_reset;
     dc->props = grlib_irqmp_properties;
+    /* Reason: pointer properties "set_pil_in", "set_pil_in_opaque" */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo grlib_irqmp_info = {
diff --git a/hw/intc/i8259_common.c b/hw/intc/i8259_common.c
index 803d037f68..9d293999be 100644
--- a/hw/intc/i8259_common.c
+++ b/hw/intc/i8259_common.c
@@ -135,9 +135,15 @@ static void pic_common_class_init(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->vmsd = &vmstate_pic_common;
-    dc->no_user = 1;
     dc->props = pic_properties_common;
     dc->realize = pic_common_realize;
+    /*
+     * Reason: unlike ordinary ISA devices, the PICs need additional
+     * wiring: its IRQ input lines are set up by board code, and the
+     * wiring of the slave to the master is hard-coded in device model
+     * code.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo pic_common_type = {
diff --git a/hw/intc/ioapic.c b/hw/intc/ioapic.c
index d866e00297..652dd47a1c 100644
--- a/hw/intc/ioapic.c
+++ b/hw/intc/ioapic.c
@@ -36,6 +36,9 @@
 
 static IOAPICCommonState *ioapics[MAX_IOAPICS];
 
+/* global variable from ioapic_common.c */
+extern int ioapic_no;
+
 static void ioapic_service(IOAPICCommonState *s)
 {
     uint8_t i;
@@ -225,14 +228,16 @@ static const MemoryRegionOps ioapic_io_ops = {
     .endianness = DEVICE_NATIVE_ENDIAN,
 };
 
-static void ioapic_init(IOAPICCommonState *s, int instance_no)
+static void ioapic_realize(DeviceState *dev, Error **errp)
 {
+    IOAPICCommonState *s = IOAPIC_COMMON(dev);
+
     memory_region_init_io(&s->io_memory, OBJECT(s), &ioapic_io_ops, s,
                           "ioapic", 0x1000);
 
-    qdev_init_gpio_in(DEVICE(s), ioapic_set_irq, IOAPIC_NUM_PINS);
+    qdev_init_gpio_in(dev, ioapic_set_irq, IOAPIC_NUM_PINS);
 
-    ioapics[instance_no] = s;
+    ioapics[ioapic_no] = s;
 }
 
 static void ioapic_class_init(ObjectClass *klass, void *data)
@@ -240,7 +245,7 @@ static void ioapic_class_init(ObjectClass *klass, void *data)
     IOAPICCommonClass *k = IOAPIC_COMMON_CLASS(klass);
     DeviceClass *dc = DEVICE_CLASS(klass);
 
-    k->init = ioapic_init;
+    k->realize = ioapic_realize;
     dc->reset = ioapic_reset_common;
 }
 
diff --git a/hw/intc/ioapic_common.c b/hw/intc/ioapic_common.c
index 6b705c1546..4d3d309b62 100644
--- a/hw/intc/ioapic_common.c
+++ b/hw/intc/ioapic_common.c
@@ -23,6 +23,14 @@
 #include "hw/i386/ioapic_internal.h"
 #include "hw/sysbus.h"
 
+/* ioapic_no count start from 0 to MAX_IOAPICS,
+ * remove as static variable from ioapic_common_init.
+ * now as a global variable, let child to increase the counter
+ * then we can drop the 'instance_no' argument
+ * and convert to our QOM's realize function
+ */
+int ioapic_no;
+
 void ioapic_reset_common(DeviceState *dev)
 {
     IOAPICCommonState *s = IOAPIC_COMMON(dev);
@@ -61,7 +69,6 @@ static void ioapic_common_realize(DeviceState *dev, Error **errp)
 {
     IOAPICCommonState *s = IOAPIC_COMMON(dev);
     IOAPICCommonClass *info;
-    static int ioapic_no;
 
     if (ioapic_no >= MAX_IOAPICS) {
         error_setg(errp, "Only %d ioapics allowed", MAX_IOAPICS);
@@ -69,7 +76,7 @@ static void ioapic_common_realize(DeviceState *dev, Error **errp)
     }
 
     info = IOAPIC_COMMON_GET_CLASS(s);
-    info->init(s, ioapic_no);
+    info->realize(dev, errp);
 
     sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->io_memory);
     ioapic_no++;
@@ -98,7 +105,6 @@ static void ioapic_common_class_init(ObjectClass *klass, void *data)
 
     dc->realize = ioapic_common_realize;
     dc->vmsd = &vmstate_ioapic_common;
-    dc->no_user = 1;
 }
 
 static const TypeInfo ioapic_common_type = {
@@ -110,9 +116,9 @@ static const TypeInfo ioapic_common_type = {
     .abstract = true,
 };
 
-static void register_types(void)
+static void ioapic_common_register_types(void)
 {
     type_register_static(&ioapic_common_type);
 }
 
-type_init(register_types)
+type_init(ioapic_common_register_types)
diff --git a/hw/intc/omap_intc.c b/hw/intc/omap_intc.c
index 7dd63da802..ad3931c112 100644
--- a/hw/intc/omap_intc.c
+++ b/hw/intc/omap_intc.c
@@ -392,6 +392,8 @@ static void omap_intc_class_init(ObjectClass *klass, void *data)
     k->init = omap_intc_init;
     dc->reset = omap_inth_reset;
     dc->props = omap_intc_properties;
+    /* Reason: pointer property "clk" */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo omap_intc_info = {
@@ -637,6 +639,8 @@ static void omap2_intc_class_init(ObjectClass *klass, void *data)
     k->init = omap2_intc_init;
     dc->reset = omap_inth_reset;
     dc->props = omap2_intc_properties;
+    /* Reason: pointer property "iclk", "fclk" */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo omap2_intc_info = {
diff --git a/hw/intc/pl190.c b/hw/intc/pl190.c
index 329680da3a..2bf359a76b 100644
--- a/hw/intc/pl190.c
+++ b/hw/intc/pl190.c
@@ -273,7 +273,6 @@ static void pl190_class_init(ObjectClass *klass, void *data)
     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 
     k->init = pl190_init;
-    dc->no_user = 1;
     dc->reset = pl190_reset;
     dc->vmsd = &vmstate_pl190;
 }
diff --git a/hw/isa/isa-bus.c b/hw/isa/isa-bus.c
index 9e104eb9a7..55d01008d3 100644
--- a/hw/isa/isa-bus.c
+++ b/hw/isa/isa-bus.c
@@ -197,7 +197,6 @@ static void isabus_bridge_class_init(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->fw_name = "isa";
-    dc->no_user = 1;
 }
 
 static const TypeInfo isabus_bridge_info = {
diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c
index 19b2198fa6..51ce12dad6 100644
--- a/hw/isa/lpc_ich9.c
+++ b/hw/isa/lpc_ich9.c
@@ -644,14 +644,17 @@ static void ich9_lpc_class_init(ObjectClass *klass, void *data)
     dc->reset = ich9_lpc_reset;
     k->init = ich9_lpc_initfn;
     dc->vmsd = &vmstate_ich9_lpc;
-    dc->no_user = 1;
     k->config_write = ich9_lpc_config_write;
     dc->desc = "ICH9 LPC bridge";
     k->vendor_id = PCI_VENDOR_ID_INTEL;
     k->device_id = PCI_DEVICE_ID_INTEL_ICH9_8;
     k->revision = ICH9_A2_LPC_REVISION;
     k->class_id = PCI_CLASS_BRIDGE_ISA;
-
+    /*
+     * Reason: part of ICH9 southbridge, needs to be wired up by
+     * pc_q35_init()
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo ich9_lpc_info = {
diff --git a/hw/isa/piix4.c b/hw/isa/piix4.c
index 1a1d4518ce..def6fe3a0f 100644
--- a/hw/isa/piix4.c
+++ b/hw/isa/piix4.c
@@ -113,8 +113,12 @@ static void piix4_class_init(ObjectClass *klass, void *data)
     k->device_id = PCI_DEVICE_ID_INTEL_82371AB_0;
     k->class_id = PCI_CLASS_BRIDGE_ISA;
     dc->desc = "ISA bridge";
-    dc->no_user = 1;
     dc->vmsd = &vmstate_piix4;
+    /*
+     * Reason: part of PIIX4 southbridge, needs to be wired up,
+     * e.g. by mips_malta_init()
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo piix4_info = {
diff --git a/hw/isa/vt82c686.c b/hw/isa/vt82c686.c
index 5fb808630f..e639357db3 100644
--- a/hw/isa/vt82c686.c
+++ b/hw/isa/vt82c686.c
@@ -480,8 +480,12 @@ static void via_class_init(ObjectClass *klass, void *data)
     k->class_id = PCI_CLASS_BRIDGE_ISA;
     k->revision = 0x40;
     dc->desc = "ISA bridge";
-    dc->no_user = 1;
     dc->vmsd = &vmstate_via;
+    /*
+     * Reason: part of VIA VT82C686 southbridge, needs to be wired up,
+     * e.g. by mips_fulong2e_init()
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo via_info = {
diff --git a/hw/mips/gt64xxx_pci.c b/hw/mips/gt64xxx_pci.c
index 3da2e67098..6398514c99 100644
--- a/hw/mips/gt64xxx_pci.c
+++ b/hw/mips/gt64xxx_pci.c
@@ -1151,12 +1151,18 @@ static int gt64120_pci_init(PCIDevice *d)
 static void gt64120_pci_class_init(ObjectClass *klass, void *data)
 {
     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
 
     k->init = gt64120_pci_init;
     k->vendor_id = PCI_VENDOR_ID_MARVELL;
     k->device_id = PCI_DEVICE_ID_MARVELL_GT6412X;
     k->revision = 0x10;
     k->class_id = PCI_CLASS_BRIDGE_HOST;
+    /*
+     * PCI-facing part of the host bridge, not usable without the
+     * host-facing part, which can't be device_add'ed, yet.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo gt64120_pci_info = {
diff --git a/hw/misc/arm_l2x0.c b/hw/misc/arm_l2x0.c
index 8e192cdf83..9e220c9a56 100644
--- a/hw/misc/arm_l2x0.c
+++ b/hw/misc/arm_l2x0.c
@@ -179,7 +179,6 @@ static void l2x0_class_init(ObjectClass *klass, void *data)
 
     k->init = l2x0_priv_init;
     dc->vmsd = &vmstate_l2x0;
-    dc->no_user = 1;
     dc->props = l2x0_properties;
     dc->reset = l2x0_priv_reset;
 }
diff --git a/hw/misc/vmport.c b/hw/misc/vmport.c
index 0b5a5644e4..cd5716a46d 100644
--- a/hw/misc/vmport.c
+++ b/hw/misc/vmport.c
@@ -162,7 +162,8 @@ static void vmport_class_initfn(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = vmport_realizefn;
-    dc->no_user = 1;
+    /* Reason: realize sets global port_state */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo vmport_info = {
diff --git a/hw/net/etraxfs_eth.c b/hw/net/etraxfs_eth.c
index 78ebbbca72..6a3c86db48 100644
--- a/hw/net/etraxfs_eth.c
+++ b/hw/net/etraxfs_eth.c
@@ -646,6 +646,8 @@ static void etraxfs_eth_class_init(ObjectClass *klass, void *data)
 
     k->init = fs_eth_init;
     dc->props = etraxfs_eth_properties;
+    /* Reason: pointer properties "dma_out", "dma_in" */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo etraxfs_eth_info = {
diff --git a/hw/net/lance.c b/hw/net/lance.c
index e339f029b7..fe18564e1e 100644
--- a/hw/net/lance.c
+++ b/hw/net/lance.c
@@ -161,6 +161,8 @@ static void lance_class_init(ObjectClass *klass, void *data)
     dc->reset = lance_reset;
     dc->vmsd = &vmstate_lance;
     dc->props = lance_properties;
+    /* Reason: pointer property "dma" */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo lance_info = {
diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index f5dc3ea845..ee96c1681b 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -599,7 +599,6 @@ static void fw_cfg_class_init(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = fw_cfg_realize;
-    dc->no_user = 1;
     dc->reset = fw_cfg_reset;
     dc->vmsd = &vmstate_fw_cfg;
     dc->props = fw_cfg_properties;
diff --git a/hw/pci-bridge/dec.c b/hw/pci-bridge/dec.c
index e5e3be829f..a6ca940d55 100644
--- a/hw/pci-bridge/dec.c
+++ b/hw/pci-bridge/dec.c
@@ -116,6 +116,7 @@ static int dec_21154_pci_host_init(PCIDevice *d)
 static void dec_21154_pci_host_class_init(ObjectClass *klass, void *data)
 {
     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
 
     k->init = dec_21154_pci_host_init;
     k->vendor_id = PCI_VENDOR_ID_DEC;
@@ -123,6 +124,11 @@ static void dec_21154_pci_host_class_init(ObjectClass *klass, void *data)
     k->revision = 0x02;
     k->class_id = PCI_CLASS_BRIDGE_PCI;
     k->is_bridge = 1;
+    /*
+     * PCI-facing part of the host bridge, not usable without the
+     * host-facing part, which can't be device_add'ed, yet.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo dec_21154_pci_host_info = {
diff --git a/hw/pci-host/apb.c b/hw/pci-host/apb.c
index 92f289f8f9..1b399ddbc3 100644
--- a/hw/pci-host/apb.c
+++ b/hw/pci-host/apb.c
@@ -516,11 +516,17 @@ static int pbm_pci_host_init(PCIDevice *d)
 static void pbm_pci_host_class_init(ObjectClass *klass, void *data)
 {
     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
 
     k->init = pbm_pci_host_init;
     k->vendor_id = PCI_VENDOR_ID_SUN;
     k->device_id = PCI_DEVICE_ID_SUN_SABRE;
     k->class_id = PCI_CLASS_BRIDGE_HOST;
+    /*
+     * PCI-facing part of the host bridge, not usable without the
+     * host-facing part, which can't be device_add'ed, yet.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo pbm_pci_host_info = {
diff --git a/hw/pci-host/bonito.c b/hw/pci-host/bonito.c
index 5086d42c13..902441f10b 100644
--- a/hw/pci-host/bonito.c
+++ b/hw/pci-host/bonito.c
@@ -806,8 +806,12 @@ static void bonito_class_init(ObjectClass *klass, void *data)
     k->revision = 0x01;
     k->class_id = PCI_CLASS_BRIDGE_HOST;
     dc->desc = "Host bridge";
-    dc->no_user = 1;
     dc->vmsd = &vmstate_bonito;
+    /*
+     * PCI-facing part of the host bridge, not usable without the
+     * host-facing part, which can't be device_add'ed, yet.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo bonito_info = {
@@ -819,11 +823,9 @@ static const TypeInfo bonito_info = {
 
 static void bonito_pcihost_class_init(ObjectClass *klass, void *data)
 {
-    DeviceClass *dc = DEVICE_CLASS(klass);
     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 
     k->init = bonito_pcihost_initfn;
-    dc->no_user = 1;
 }
 
 static const TypeInfo bonito_pcihost_info = {
diff --git a/hw/pci-host/grackle.c b/hw/pci-host/grackle.c
index 75b60d36ac..6c7cfdbeb2 100644
--- a/hw/pci-host/grackle.c
+++ b/hw/pci-host/grackle.c
@@ -130,7 +130,11 @@ static void grackle_pci_class_init(ObjectClass *klass, void *data)
     k->device_id = PCI_DEVICE_ID_MOTOROLA_MPC106;
     k->revision  = 0x00;
     k->class_id  = PCI_CLASS_BRIDGE_HOST;
-    dc->no_user = 1;
+    /*
+     * PCI-facing part of the host bridge, not usable without the
+     * host-facing part, which can't be device_add'ed, yet.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo grackle_pci_info = {
@@ -143,10 +147,8 @@ static const TypeInfo grackle_pci_info = {
 static void pci_grackle_class_init(ObjectClass *klass, void *data)
 {
     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
-    DeviceClass *dc = DEVICE_CLASS(klass);
 
     k->init = pci_grackle_init_device;
-    dc->no_user = 1;
 }
 
 static const TypeInfo grackle_pci_host_info = {
diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c
index 63be7f6cee..cc97150a90 100644
--- a/hw/pci-host/piix.c
+++ b/hw/pci-host/piix.c
@@ -635,7 +635,6 @@ static void piix3_class_init(ObjectClass *klass, void *data)
 
     dc->desc        = "ISA bridge";
     dc->vmsd        = &vmstate_piix3;
-    dc->no_user     = 1,
     k->no_hotplug   = 1;
     k->init         = piix3_initfn;
     k->config_write = piix3_write_config;
@@ -643,6 +642,11 @@ static void piix3_class_init(ObjectClass *klass, void *data)
     /* 82371SB PIIX3 PCI-to-ISA bridge (Step A1) */
     k->device_id    = PCI_DEVICE_ID_INTEL_82371SB_0;
     k->class_id     = PCI_CLASS_BRIDGE_ISA;
+    /*
+     * Reason: part of PIIX3 southbridge, needs to be wired up by
+     * pc_piix.c's pc_init1()
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo piix3_info = {
@@ -659,7 +663,6 @@ static void piix3_xen_class_init(ObjectClass *klass, void *data)
 
     dc->desc        = "ISA bridge";
     dc->vmsd        = &vmstate_piix3;
-    dc->no_user     = 1;
     k->no_hotplug   = 1;
     k->init         = piix3_initfn;
     k->config_write = piix3_write_config_xen;
@@ -667,6 +670,11 @@ static void piix3_xen_class_init(ObjectClass *klass, void *data)
     /* 82371SB PIIX3 PCI-to-ISA bridge (Step A1) */
     k->device_id    = PCI_DEVICE_ID_INTEL_82371SB_0;
     k->class_id     = PCI_CLASS_BRIDGE_ISA;
+    /*
+     * Reason: part of PIIX3 southbridge, needs to be wired up by
+     * pc_piix.c's pc_init1()
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 };
 
 static const TypeInfo piix3_xen_info = {
@@ -689,8 +697,12 @@ static void i440fx_class_init(ObjectClass *klass, void *data)
     k->revision = 0x02;
     k->class_id = PCI_CLASS_BRIDGE_HOST;
     dc->desc = "Host bridge";
-    dc->no_user = 1;
     dc->vmsd = &vmstate_i440fx;
+    /*
+     * PCI-facing part of the host bridge, not usable without the
+     * host-facing part, which can't be device_add'ed, yet.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo i440fx_info = {
@@ -727,7 +739,6 @@ static void i440fx_pcihost_class_init(ObjectClass *klass, void *data)
     hc->root_bus_path = i440fx_pcihost_root_bus_path;
     dc->realize = i440fx_pcihost_realize;
     dc->fw_name = "pci";
-    dc->no_user = 1;
     dc->props = i440fx_props;
 }
 
diff --git a/hw/pci-host/ppce500.c b/hw/pci-host/ppce500.c
index f00793d819..c80b7cb2f5 100644
--- a/hw/pci-host/ppce500.c
+++ b/hw/pci-host/ppce500.c
@@ -387,6 +387,11 @@ static void e500_host_bridge_class_init(ObjectClass *klass, void *data)
     k->device_id = PCI_DEVICE_ID_MPC8533E;
     k->class_id = PCI_CLASS_PROCESSOR_POWERPC;
     dc->desc = "Host bridge";
+    /*
+     * PCI-facing part of the host bridge, not usable without the
+     * host-facing part, which can't be device_add'ed, yet.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo e500_host_bridge_info = {
diff --git a/hw/pci-host/prep.c b/hw/pci-host/prep.c
index 0e71fdbfb1..042dc8f225 100644
--- a/hw/pci-host/prep.c
+++ b/hw/pci-host/prep.c
@@ -198,7 +198,11 @@ static void raven_class_init(ObjectClass *klass, void *data)
     k->class_id = PCI_CLASS_BRIDGE_HOST;
     dc->desc = "PReP Host Bridge - Motorola Raven";
     dc->vmsd = &vmstate_raven;
-    dc->no_user = 1;
+    /*
+     * PCI-facing part of the host bridge, not usable without the
+     * host-facing part, which can't be device_add'ed, yet.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo raven_info = {
@@ -215,7 +219,6 @@ static void raven_pcihost_class_init(ObjectClass *klass, void *data)
     set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
     dc->realize = raven_pcihost_realizefn;
     dc->fw_name = "pci";
-    dc->no_user = 1;
 }
 
 static const TypeInfo raven_pcihost_info = {
diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
index 81c82404d6..4bc2e0118e 100644
--- a/hw/pci-host/q35.c
+++ b/hw/pci-host/q35.c
@@ -403,6 +403,11 @@ static void mch_class_init(ObjectClass *klass, void *data)
     k->device_id = PCI_DEVICE_ID_INTEL_Q35_MCH;
     k->revision = MCH_HOST_BRIDGE_REVISION_DEFAULT;
     k->class_id = PCI_CLASS_BRIDGE_HOST;
+    /*
+     * PCI-facing part of the host bridge, not usable without the
+     * host-facing part, which can't be device_add'ed, yet.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo mch_info = {
diff --git a/hw/pci-host/uninorth.c b/hw/pci-host/uninorth.c
index adc1d89010..e72fe2a70b 100644
--- a/hw/pci-host/uninorth.c
+++ b/hw/pci-host/uninorth.c
@@ -351,12 +351,18 @@ static int unin_internal_pci_host_init(PCIDevice *d)
 static void unin_main_pci_host_class_init(ObjectClass *klass, void *data)
 {
     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
 
     k->init      = unin_main_pci_host_init;
     k->vendor_id = PCI_VENDOR_ID_APPLE;
     k->device_id = PCI_DEVICE_ID_APPLE_UNI_N_PCI;
     k->revision  = 0x00;
     k->class_id  = PCI_CLASS_BRIDGE_HOST;
+    /*
+     * PCI-facing part of the host bridge, not usable without the
+     * host-facing part, which can't be device_add'ed, yet.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo unin_main_pci_host_info = {
@@ -369,12 +375,18 @@ static const TypeInfo unin_main_pci_host_info = {
 static void u3_agp_pci_host_class_init(ObjectClass *klass, void *data)
 {
     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
 
     k->init      = u3_agp_pci_host_init;
     k->vendor_id = PCI_VENDOR_ID_APPLE;
     k->device_id = PCI_DEVICE_ID_APPLE_U3_AGP;
     k->revision  = 0x00;
     k->class_id  = PCI_CLASS_BRIDGE_HOST;
+    /*
+     * PCI-facing part of the host bridge, not usable without the
+     * host-facing part, which can't be device_add'ed, yet.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo u3_agp_pci_host_info = {
@@ -387,12 +399,18 @@ static const TypeInfo u3_agp_pci_host_info = {
 static void unin_agp_pci_host_class_init(ObjectClass *klass, void *data)
 {
     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
 
     k->init      = unin_agp_pci_host_init;
     k->vendor_id = PCI_VENDOR_ID_APPLE;
     k->device_id = PCI_DEVICE_ID_APPLE_UNI_N_AGP;
     k->revision  = 0x00;
     k->class_id  = PCI_CLASS_BRIDGE_HOST;
+    /*
+     * PCI-facing part of the host bridge, not usable without the
+     * host-facing part, which can't be device_add'ed, yet.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo unin_agp_pci_host_info = {
@@ -405,12 +423,18 @@ static const TypeInfo unin_agp_pci_host_info = {
 static void unin_internal_pci_host_class_init(ObjectClass *klass, void *data)
 {
     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
 
     k->init      = unin_internal_pci_host_init;
     k->vendor_id = PCI_VENDOR_ID_APPLE;
     k->device_id = PCI_DEVICE_ID_APPLE_UNI_N_I_PCI;
     k->revision  = 0x00;
     k->class_id  = PCI_CLASS_BRIDGE_HOST;
+    /*
+     * PCI-facing part of the host bridge, not usable without the
+     * host-facing part, which can't be device_add'ed, yet.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo unin_internal_pci_host_info = {
diff --git a/hw/pci-host/versatile.c b/hw/pci-host/versatile.c
index 6b28929d26..71ff0de303 100644
--- a/hw/pci-host/versatile.c
+++ b/hw/pci-host/versatile.c
@@ -467,11 +467,17 @@ static int versatile_pci_host_init(PCIDevice *d)
 static void versatile_pci_host_class_init(ObjectClass *klass, void *data)
 {
     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
 
     k->init = versatile_pci_host_init;
     k->vendor_id = PCI_VENDOR_ID_XILINX;
     k->device_id = PCI_DEVICE_ID_XILINX_XC2VP30;
     k->class_id = PCI_CLASS_PROCESSOR_CO;
+    /*
+     * PCI-facing part of the host bridge, not usable without the
+     * host-facing part, which can't be device_add'ed, yet.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo versatile_pci_host_info = {
diff --git a/hw/pci/pci_bridge.c b/hw/pci/pci_bridge.c
index f72872ebcf..355c3e1b06 100644
--- a/hw/pci/pci_bridge.c
+++ b/hw/pci/pci_bridge.c
@@ -391,7 +391,7 @@ void pci_bridge_exitfn(PCIDevice *pci_dev)
     pci_bridge_region_cleanup(s, s->windows);
     memory_region_destroy(&s->address_space_mem);
     memory_region_destroy(&s->address_space_io);
-    /* qbus_free() is called automatically during device deletion */
+    /* object_unparent() is called automatically during device deletion */
 }
 
 /*
diff --git a/hw/ppc/ppc4xx_pci.c b/hw/ppc/ppc4xx_pci.c
index d2d6f65e6c..4cb78518a3 100644
--- a/hw/ppc/ppc4xx_pci.c
+++ b/hw/ppc/ppc4xx_pci.c
@@ -380,6 +380,11 @@ static void ppc4xx_host_bridge_class_init(ObjectClass *klass, void *data)
     k->vendor_id    = PCI_VENDOR_ID_IBM;
     k->device_id    = PCI_DEVICE_ID_IBM_440GX;
     k->class_id     = PCI_CLASS_BRIDGE_OTHER;
+    /*
+     * PCI-facing part of the host bridge, not usable without the
+     * host-facing part, which can't be device_add'ed, yet.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo ppc4xx_host_bridge_info = {
diff --git a/hw/ppc/spapr_vio.c b/hw/ppc/spapr_vio.c
index fee6195f95..4e33f462d9 100644
--- a/hw/ppc/spapr_vio.c
+++ b/hw/ppc/spapr_vio.c
@@ -528,11 +528,9 @@ static int spapr_vio_bridge_init(SysBusDevice *dev)
 
 static void spapr_vio_bridge_class_init(ObjectClass *klass, void *data)
 {
-    DeviceClass *dc = DEVICE_CLASS(klass);
     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 
     k->init = spapr_vio_bridge_init;
-    dc->no_user = 1;
 }
 
 static const TypeInfo spapr_vio_bridge_info = {
diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
index 65d39da314..1a6397b88e 100644
--- a/hw/s390x/ipl.c
+++ b/hw/s390x/ipl.c
@@ -182,7 +182,6 @@ static void s390_ipl_class_init(ObjectClass *klass, void *data)
     k->init = s390_ipl_init;
     dc->props = s390_ipl_properties;
     dc->reset = s390_ipl_reset;
-    dc->no_user = 1;
 }
 
 static const TypeInfo s390_ipl_info = {
diff --git a/hw/s390x/s390-virtio-bus.c b/hw/s390x/s390-virtio-bus.c
index 6a831114da..46c5ff1898 100644
--- a/hw/s390x/s390-virtio-bus.c
+++ b/hw/s390x/s390-virtio-bus.c
@@ -676,11 +676,9 @@ static int s390_virtio_bridge_init(SysBusDevice *dev)
 
 static void s390_virtio_bridge_class_init(ObjectClass *klass, void *data)
 {
-    DeviceClass *dc = DEVICE_CLASS(klass);
     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 
     k->init = s390_virtio_bridge_init;
-    dc->no_user = 1;
 }
 
 static const TypeInfo s390_virtio_bridge_info = {
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index ecc80ecaf7..4b6250dda9 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -1283,11 +1283,9 @@ static int virtual_css_bridge_init(SysBusDevice *dev)
 
 static void virtual_css_bridge_class_init(ObjectClass *klass, void *data)
 {
-    DeviceClass *dc = DEVICE_CLASS(klass);
     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 
     k->init = virtual_css_bridge_init;
-    dc->no_user = 1;
 }
 
 static const TypeInfo virtual_css_bridge_info = {
diff --git a/hw/sd/pl181.c b/hw/sd/pl181.c
index c35896d28c..462558b76d 100644
--- a/hw/sd/pl181.c
+++ b/hw/sd/pl181.c
@@ -506,7 +506,6 @@ static void pl181_class_init(ObjectClass *klass, void *data)
     sdc->init = pl181_init;
     k->vmsd = &vmstate_pl181;
     k->reset = pl181_reset;
-    k->no_user = 1;
 }
 
 static const TypeInfo pl181_info = {
diff --git a/hw/sh4/sh_pci.c b/hw/sh4/sh_pci.c
index e81176a11e..a2f6d9e0b6 100644
--- a/hw/sh4/sh_pci.c
+++ b/hw/sh4/sh_pci.c
@@ -162,10 +162,16 @@ static int sh_pci_host_init(PCIDevice *d)
 static void sh_pci_host_class_init(ObjectClass *klass, void *data)
 {
     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
 
     k->init = sh_pci_host_init;
     k->vendor_id = PCI_VENDOR_ID_HITACHI;
     k->device_id = PCI_DEVICE_ID_HITACHI_SH7751R;
+    /*
+     * PCI-facing part of the host bridge, not usable without the
+     * host-facing part, which can't be device_add'ed, yet.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo sh_pci_host_info = {
diff --git a/hw/timer/arm_mptimer.c b/hw/timer/arm_mptimer.c
index d9f9494f26..35a0a2356f 100644
--- a/hw/timer/arm_mptimer.c
+++ b/hw/timer/arm_mptimer.c
@@ -274,7 +274,6 @@ static void arm_mptimer_class_init(ObjectClass *klass, void *data)
     dc->realize = arm_mptimer_realize;
     dc->vmsd = &vmstate_arm_mptimer;
     dc->reset = arm_mptimer_reset;
-    dc->no_user = 1;
     dc->props = arm_mptimer_properties;
 }
 
diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index bb3bf98745..2fbbeb1735 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -765,7 +765,6 @@ static void hpet_device_class_init(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = hpet_realize;
-    dc->no_user = 1;
     dc->reset = hpet_reset;
     dc->vmsd = &vmstate_hpet;
     dc->props = hpet_device_properties;
diff --git a/hw/timer/i8254_common.c b/hw/timer/i8254_common.c
index e8fb971488..9db5c9d129 100644
--- a/hw/timer/i8254_common.c
+++ b/hw/timer/i8254_common.c
@@ -282,7 +282,12 @@ static void pit_common_class_init(ObjectClass *klass, void *data)
 
     dc->realize = pit_common_realize;
     dc->vmsd = &vmstate_pit_common;
-    dc->no_user = 1;
+    /*
+     * Reason: unlike ordinary ISA devices, the PIT may need to be
+     * wired to the HPET, and because of that, some wiring is always
+     * done by board code.
+     */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo pit_common_type = {
diff --git a/hw/timer/m48t59.c b/hw/timer/m48t59.c
index be0592b53d..3cfb18a8b3 100644
--- a/hw/timer/m48t59.c
+++ b/hw/timer/m48t59.c
@@ -750,9 +750,10 @@ static void m48t59_isa_class_init(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = m48t59_isa_realize;
-    dc->no_user = 1;
     dc->reset = m48t59_reset_isa;
     dc->props = m48t59_isa_properties;
+    /* Reason: needs to be wired up by m48t59_init_isa() */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo m48t59_isa_info = {
diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c
index b0116381c0..6fb124fead 100644
--- a/hw/timer/mc146818rtc.c
+++ b/hw/timer/mc146818rtc.c
@@ -899,9 +899,10 @@ static void rtc_class_initfn(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = rtc_realizefn;
-    dc->no_user = 1;
     dc->vmsd = &vmstate_rtc;
     dc->props = mc146818rtc_properties;
+    /* Reason: needs to be wired up by rtc_init() */
+    dc->cannot_instantiate_with_device_add_yet = true;
 }
 
 static const TypeInfo mc146818rtc_info = {
diff --git a/hw/timer/pl031.c b/hw/timer/pl031.c
index 65928a4819..34d9b44e7e 100644
--- a/hw/timer/pl031.c
+++ b/hw/timer/pl031.c
@@ -251,7 +251,6 @@ static void pl031_class_init(ObjectClass *klass, void *data)
     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 
     k->init = pl031_init;
-    dc->no_user = 1;
     dc->vmsd = &vmstate_pl031;
 }
 
diff --git a/hw/xen/xen_apic.c b/hw/xen/xen_apic.c
index 9f91e0f0c9..63bb7f77c6 100644
--- a/hw/xen/xen_apic.c
+++ b/hw/xen/xen_apic.c
@@ -36,8 +36,10 @@ static const MemoryRegionOps xen_apic_io_ops = {
     .endianness = DEVICE_NATIVE_ENDIAN,
 };
 
-static void xen_apic_init(APICCommonState *s)
+static void xen_apic_realize(DeviceState *dev, Error **errp)
 {
+    APICCommonState *s = APIC_COMMON(dev);
+
     memory_region_init_io(&s->io_memory, OBJECT(s), &xen_apic_io_ops, s,
                           "xen-apic-msi", APIC_SPACE_SIZE);
 
@@ -72,7 +74,7 @@ static void xen_apic_class_init(ObjectClass *klass, void *data)
 {
     APICCommonClass *k = APIC_COMMON_CLASS(klass);
 
-    k->init = xen_apic_init;
+    k->realize = xen_apic_realize;
     k->set_base = xen_apic_set_base;
     k->set_tpr = xen_apic_set_tpr;
     k->get_tpr = xen_apic_get_tpr;