qdev: Replace no_user by cannot_instantiate_with_device_add_yet

In an ideal world, machines can be built by wiring devices together
with configuration, not code.  Unfortunately, that's not the world we
live in right now.  We still have quite a few devices that need to be
wired up by code.  If you try to device_add such a device, it'll fail
in sometimes mysterious ways.  If you're lucky, you get an
unmysterious immediate crash.

To protect users from such badness, DeviceClass member no_user used to
make device models unavailable with -device / device_add, but that
regressed in commit 18b6dad.  The device model is still omitted from
help, but is available anyway.

Attempts to fix the regression have been rejected with the argument
that the purpose of no_user isn't clear, and it's prone to misuse.

This commit clarifies no_user's purpose.  Anthony suggested to rename
it cannot_instantiate_with_device_add_yet_due_to_internal_bugs, which
I shorten somewhat to keep checkpatch happy.  While there, make it
bool.

Every use of cannot_instantiate_with_device_add_yet gets a FIXME
comment asking for rationale.  The next few commits will clean them
all up, either by providing a rationale, or by getting rid of the use.

With that done, the regression fix is hopefully acceptable.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marcel Apfelbaum <marcel.a@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>

48 files changed, 69 insertions, 57 deletions

diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
index 93849c8d36..dd11534c41 100644
--- a/hw/acpi/piix4.c
+++ b/hw/acpi/piix4.c
@@ -544,7 +544,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->vmsd = &vmstate_acpi;
     dc->props = piix4_pm_properties;
 }
diff --git a/hw/alpha/typhoon.c b/hw/alpha/typhoon.c
index 59e1bb8388..60987ede5a 100644
--- a/hw/alpha/typhoon.c
+++ b/hw/alpha/typhoon.c
@@ -938,7 +938,7 @@ static void typhoon_pcihost_class_init(ObjectClass *klass, void *data)
     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 
     k->init = typhoon_pcihost_init;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo typhoon_pcihost_info = {
diff --git a/hw/arm/versatilepb.c b/hw/arm/versatilepb.c
index f7e8b7e8fa..bb0c0ba7a4 100644
--- a/hw/arm/versatilepb.c
+++ b/hw/arm/versatilepb.c
@@ -390,7 +390,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->vmsd = &vmstate_vpb_sic;
 }
 
diff --git a/hw/audio/pcspk.c b/hw/audio/pcspk.c
index 9004ce3d1f..8e3e178f38 100644
--- a/hw/audio/pcspk.c
+++ b/hw/audio/pcspk.c
@@ -192,7 +192,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->props = pcspk_properties;
 }
 
diff --git a/hw/audio/pl041.c b/hw/audio/pl041.c
index 5393b520b7..8ba661a32c 100644
--- a/hw/audio/pl041.c
+++ b/hw/audio/pl041.c
@@ -632,7 +632,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     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..86f4920ba8 100644
--- a/hw/block/fdc.c
+++ b/hw/block/fdc.c
@@ -2234,7 +2234,7 @@ static void isabus_fdc_class_init(ObjectClass *klass, void *data)
 
     dc->realize = isabus_fdc_realize;
     dc->fw_name = "fdc";
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->reset = fdctrl_external_reset_isa;
     dc->vmsd = &vmstate_isa_fdc;
     dc->props = isa_fdc_properties;
diff --git a/hw/display/pl110.c b/hw/display/pl110.c
index 790e5108ed..7ad5972f0a 100644
--- a/hw/display/pl110.c
+++ b/hw/display/pl110.c
@@ -496,7 +496,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->vmsd = &vmstate_pl110;
 }
 
diff --git a/hw/dma/pl080.c b/hw/dma/pl080.c
index 35b90155a2..a515621338 100644
--- a/hw/dma/pl080.c
+++ b/hw/dma/pl080.c
@@ -381,7 +381,7 @@ static void pl080_class_init(ObjectClass *oc, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(oc);
 
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->vmsd = &vmstate_pl080;
 }
 
diff --git a/hw/i2c/smbus_ich9.c b/hw/i2c/smbus_ich9.c
index ca229789f4..c1ffa34fd4 100644
--- a/hw/i2c/smbus_ich9.c
+++ b/hw/i2c/smbus_ich9.c
@@ -97,7 +97,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->vmsd = &vmstate_ich9_smbus;
     dc->desc = "ICH9 SMBUS Bridge";
     k->init = ich9_smbus_initfn;
diff --git a/hw/i386/kvm/clock.c b/hw/i386/kvm/clock.c
index 383938d1bc..abd2ce8012 100644
--- a/hw/i386/kvm/clock.c
+++ b/hw/i386/kvm/clock.c
@@ -114,7 +114,7 @@ static void kvmclock_class_init(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = kvmclock_realize;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->vmsd = &kvmclock_vmsd;
 }
 
diff --git a/hw/i386/kvmvapic.c b/hw/i386/kvmvapic.c
index 2d876009fc..f1a0a9d9cd 100644
--- a/hw/i386/kvmvapic.c
+++ b/hw/i386/kvmvapic.c
@@ -827,7 +827,7 @@ static void vapic_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
 
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     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..1e6e8af207 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -547,7 +547,7 @@ static void port92_class_initfn(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
 
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->realize = port92_realizefn;
     dc->reset = port92_reset;
     dc->vmsd = &vmstate_port92_isa;
diff --git a/hw/ide/piix.c b/hw/ide/piix.c
index ab36749417..27b08e11b3 100644
--- a/hw/ide/piix.c
+++ b/hw/ide/piix.c
@@ -248,7 +248,7 @@ 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;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo piix3_ide_info = {
@@ -267,7 +267,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->unplug = pci_piix3_xen_ide_unplug;
 }
 
@@ -289,7 +289,7 @@ 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;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo piix4_ide_info = {
diff --git a/hw/ide/via.c b/hw/ide/via.c
index 99468c773e..b556c14ac7 100644
--- a/hw/ide/via.c
+++ b/hw/ide/via.c
@@ -225,7 +225,7 @@ 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;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo via_ide_info = {
diff --git a/hw/input/pckbd.c b/hw/input/pckbd.c
index ce86237cf3..dee31a6ea3 100644
--- a/hw/input/pckbd.c
+++ b/hw/input/pckbd.c
@@ -522,7 +522,7 @@ static void i8042_class_initfn(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = i8042_realizefn;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->vmsd = &vmstate_kbd_isa;
 }
 
diff --git a/hw/input/vmmouse.c b/hw/input/vmmouse.c
index abd032b794..600e4a23d5 100644
--- a/hw/input/vmmouse.c
+++ b/hw/input/vmmouse.c
@@ -282,7 +282,7 @@ static void vmmouse_class_initfn(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = vmmouse_realizefn;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->reset = vmmouse_reset;
     dc->vmsd = &vmstate_vmmouse;
     dc->props = vmmouse_properties;
diff --git a/hw/intc/apic_common.c b/hw/intc/apic_common.c
index a0beb10863..ea420c7188 100644
--- a/hw/intc/apic_common.c
+++ b/hw/intc/apic_common.c
@@ -386,7 +386,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->props = apic_properties_common;
     idc->init = apic_init_common;
 }
diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c
index d431b7a881..24ad27689d 100644
--- a/hw/intc/arm_gic.c
+++ b/hw/intc/arm_gic.c
@@ -704,7 +704,7 @@ 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;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     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 c7658508dd..214a585d9b 100644
--- a/hw/intc/arm_gic_common.c
+++ b/hw/intc/arm_gic_common.c
@@ -156,7 +156,7 @@ 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;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 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..a0bbf12cdb 100644
--- a/hw/intc/arm_gic_kvm.c
+++ b/hw/intc/arm_gic_kvm.c
@@ -150,7 +150,7 @@ 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;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo kvm_arm_gic_info = {
diff --git a/hw/intc/i8259_common.c b/hw/intc/i8259_common.c
index 803d037f68..2acdbfed17 100644
--- a/hw/intc/i8259_common.c
+++ b/hw/intc/i8259_common.c
@@ -135,7 +135,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->props = pic_properties_common;
     dc->realize = pic_common_realize;
 }
diff --git a/hw/intc/ioapic_common.c b/hw/intc/ioapic_common.c
index 6b705c1546..cc5a80de9c 100644
--- a/hw/intc/ioapic_common.c
+++ b/hw/intc/ioapic_common.c
@@ -98,7 +98,7 @@ static void ioapic_common_class_init(ObjectClass *klass, void *data)
 
     dc->realize = ioapic_common_realize;
     dc->vmsd = &vmstate_ioapic_common;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo ioapic_common_type = {
diff --git a/hw/intc/pl190.c b/hw/intc/pl190.c
index 329680da3a..b16bc022e7 100644
--- a/hw/intc/pl190.c
+++ b/hw/intc/pl190.c
@@ -273,7 +273,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->reset = pl190_reset;
     dc->vmsd = &vmstate_pl190;
 }
diff --git a/hw/isa/isa-bus.c b/hw/isa/isa-bus.c
index 9e104eb9a7..6b2114d925 100644
--- a/hw/isa/isa-bus.c
+++ b/hw/isa/isa-bus.c
@@ -197,7 +197,7 @@ static void isabus_bridge_class_init(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->fw_name = "isa";
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo isabus_bridge_info = {
diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c
index 19b2198fa6..c1ca4d4f71 100644
--- a/hw/isa/lpc_ich9.c
+++ b/hw/isa/lpc_ich9.c
@@ -644,7 +644,7 @@ 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;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     k->config_write = ich9_lpc_config_write;
     dc->desc = "ICH9 LPC bridge";
     k->vendor_id = PCI_VENDOR_ID_INTEL;
diff --git a/hw/isa/piix4.c b/hw/isa/piix4.c
index 1a1d4518ce..d9dac6163c 100644
--- a/hw/isa/piix4.c
+++ b/hw/isa/piix4.c
@@ -113,7 +113,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->vmsd = &vmstate_piix4;
 }
 
diff --git a/hw/isa/vt82c686.c b/hw/isa/vt82c686.c
index 5fb808630f..b06d15e9d0 100644
--- a/hw/isa/vt82c686.c
+++ b/hw/isa/vt82c686.c
@@ -480,7 +480,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->vmsd = &vmstate_via;
 }
 
diff --git a/hw/misc/arm_l2x0.c b/hw/misc/arm_l2x0.c
index 8e192cdf83..ceea99dd0e 100644
--- a/hw/misc/arm_l2x0.c
+++ b/hw/misc/arm_l2x0.c
@@ -179,7 +179,7 @@ static void l2x0_class_init(ObjectClass *klass, void *data)
 
     k->init = l2x0_priv_init;
     dc->vmsd = &vmstate_l2x0;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->props = l2x0_properties;
     dc->reset = l2x0_priv_reset;
 }
diff --git a/hw/misc/vmport.c b/hw/misc/vmport.c
index 0b5a5644e4..94ae6aeaae 100644
--- a/hw/misc/vmport.c
+++ b/hw/misc/vmport.c
@@ -162,7 +162,7 @@ static void vmport_class_initfn(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = vmport_realizefn;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo vmport_info = {
diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index f5dc3ea845..6075bfc63c 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -599,7 +599,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->reset = fw_cfg_reset;
     dc->vmsd = &vmstate_fw_cfg;
     dc->props = fw_cfg_properties;
diff --git a/hw/pci-host/bonito.c b/hw/pci-host/bonito.c
index 5086d42c13..2e08e9d801 100644
--- a/hw/pci-host/bonito.c
+++ b/hw/pci-host/bonito.c
@@ -806,7 +806,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->vmsd = &vmstate_bonito;
 }
 
@@ -823,7 +823,7 @@ static void bonito_pcihost_class_init(ObjectClass *klass, void *data)
     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 
     k->init = bonito_pcihost_initfn;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo bonito_pcihost_info = {
diff --git a/hw/pci-host/grackle.c b/hw/pci-host/grackle.c
index 75b60d36ac..ba6017fc52 100644
--- a/hw/pci-host/grackle.c
+++ b/hw/pci-host/grackle.c
@@ -130,7 +130,7 @@ 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;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo grackle_pci_info = {
@@ -146,7 +146,7 @@ static void pci_grackle_class_init(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     k->init = pci_grackle_init_device;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo grackle_pci_host_info = {
diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c
index 63be7f6cee..333358e9e5 100644
--- a/hw/pci-host/piix.c
+++ b/hw/pci-host/piix.c
@@ -635,7 +635,7 @@ static void piix3_class_init(ObjectClass *klass, void *data)
 
     dc->desc        = "ISA bridge";
     dc->vmsd        = &vmstate_piix3;
-    dc->no_user     = 1,
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     k->no_hotplug   = 1;
     k->init         = piix3_initfn;
     k->config_write = piix3_write_config;
@@ -659,7 +659,7 @@ static void piix3_xen_class_init(ObjectClass *klass, void *data)
 
     dc->desc        = "ISA bridge";
     dc->vmsd        = &vmstate_piix3;
-    dc->no_user     = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     k->no_hotplug   = 1;
     k->init         = piix3_initfn;
     k->config_write = piix3_write_config_xen;
@@ -689,7 +689,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->vmsd = &vmstate_i440fx;
 }
 
@@ -727,7 +727,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->props = i440fx_props;
 }
 
diff --git a/hw/pci-host/prep.c b/hw/pci-host/prep.c
index 0e71fdbfb1..58b8c5eaa3 100644
--- a/hw/pci-host/prep.c
+++ b/hw/pci-host/prep.c
@@ -198,7 +198,7 @@ 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;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo raven_info = {
@@ -215,7 +215,7 @@ 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;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo raven_pcihost_info = {
diff --git a/hw/ppc/spapr_vio.c b/hw/ppc/spapr_vio.c
index fee6195f95..e328f5338e 100644
--- a/hw/ppc/spapr_vio.c
+++ b/hw/ppc/spapr_vio.c
@@ -532,7 +532,7 @@ static void spapr_vio_bridge_class_init(ObjectClass *klass, void *data)
     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 
     k->init = spapr_vio_bridge_init;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo spapr_vio_bridge_info = {
diff --git a/hw/s390x/ipl.c b/hw/s390x/ipl.c
index 65d39da314..26a717cdda 100644
--- a/hw/s390x/ipl.c
+++ b/hw/s390x/ipl.c
@@ -182,7 +182,7 @@ 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;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo s390_ipl_info = {
diff --git a/hw/s390x/s390-virtio-bus.c b/hw/s390x/s390-virtio-bus.c
index 6a831114da..eccc3e7508 100644
--- a/hw/s390x/s390-virtio-bus.c
+++ b/hw/s390x/s390-virtio-bus.c
@@ -680,7 +680,7 @@ static void s390_virtio_bridge_class_init(ObjectClass *klass, void *data)
     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 
     k->init = s390_virtio_bridge_init;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo s390_virtio_bridge_info = {
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index ecc80ecaf7..3be92681c0 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -1287,7 +1287,7 @@ static void virtual_css_bridge_class_init(ObjectClass *klass, void *data)
     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 
     k->init = virtual_css_bridge_init;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo virtual_css_bridge_info = {
diff --git a/hw/sd/pl181.c b/hw/sd/pl181.c
index c35896d28c..d830188875 100644
--- a/hw/sd/pl181.c
+++ b/hw/sd/pl181.c
@@ -506,7 +506,7 @@ 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;
+    k->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo pl181_info = {
diff --git a/hw/timer/arm_mptimer.c b/hw/timer/arm_mptimer.c
index d9f9494f26..1dc44cd3d1 100644
--- a/hw/timer/arm_mptimer.c
+++ b/hw/timer/arm_mptimer.c
@@ -274,7 +274,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->props = arm_mptimer_properties;
 }
 
diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index bb3bf98745..74e0297f82 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -765,7 +765,7 @@ static void hpet_device_class_init(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = hpet_realize;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     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..dc2196c1ef 100644
--- a/hw/timer/i8254_common.c
+++ b/hw/timer/i8254_common.c
@@ -282,7 +282,7 @@ static void pit_common_class_init(ObjectClass *klass, void *data)
 
     dc->realize = pit_common_realize;
     dc->vmsd = &vmstate_pit_common;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo pit_common_type = {
diff --git a/hw/timer/m48t59.c b/hw/timer/m48t59.c
index be0592b53d..e079d41818 100644
--- a/hw/timer/m48t59.c
+++ b/hw/timer/m48t59.c
@@ -750,7 +750,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->reset = m48t59_reset_isa;
     dc->props = m48t59_isa_properties;
 }
diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c
index b0116381c0..ad61e2cffb 100644
--- a/hw/timer/mc146818rtc.c
+++ b/hw/timer/mc146818rtc.c
@@ -899,7 +899,7 @@ static void rtc_class_initfn(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->realize = rtc_realizefn;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->vmsd = &vmstate_rtc;
     dc->props = mc146818rtc_properties;
 }
diff --git a/hw/timer/pl031.c b/hw/timer/pl031.c
index 65928a4819..2f7360cab9 100644
--- a/hw/timer/pl031.c
+++ b/hw/timer/pl031.c
@@ -251,7 +251,7 @@ 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->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
     dc->vmsd = &vmstate_pl031;
 }
 
diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
index f2043a69c2..c8945a412a 100644
--- a/include/hw/qdev-core.h
+++ b/include/hw/qdev-core.h
@@ -97,7 +97,18 @@ typedef struct DeviceClass {
     const char *fw_name;
     const char *desc;
     Property *props;
-    int no_user;
+
+    /*
+     * Shall we hide this device model from -device / device_add?
+     * All devices should support instantiation with device_add, and
+     * this flag should not exist.  But we're not there, yet.  Some
+     * devices fail to instantiate with cryptic error messages.
+     * Others instantiate, but don't work.  Exposing users to such
+     * behavior would be cruel; this flag serves to protect them.  It
+     * should never be set without a comment explaining why it is set.
+     * TODO remove once we're there
+     */
+    bool cannot_instantiate_with_device_add_yet;
 
     /* callbacks */
     void (*reset)(DeviceState *dev);
diff --git a/qdev-monitor.c b/qdev-monitor.c
index dc37a43dd9..f2a5a6fc56 100644
--- a/qdev-monitor.c
+++ b/qdev-monitor.c
@@ -87,7 +87,7 @@ static void qdev_print_devinfo(DeviceClass *dc)
     if (dc->desc) {
         error_printf(", desc \"%s\"", dc->desc);
     }
-    if (dc->no_user) {
+    if (dc->cannot_instantiate_with_device_add_yet) {
         error_printf(", no-user");
     }
     error_printf("\n");
@@ -127,7 +127,8 @@ static void qdev_print_devinfos(bool show_no_user)
             if ((i < DEVICE_CATEGORY_MAX
                  ? !test_bit(i, dc->categories)
                  : !bitmap_empty(dc->categories, DEVICE_CATEGORY_MAX))
-                || (!show_no_user && dc->no_user)) {
+                || (!show_no_user
+                    && dc->cannot_instantiate_with_device_add_yet)) {
                 continue;
             }
             if (!cat_printed) {
diff --git a/qom/cpu.c b/qom/cpu.c
index 818fb26dd4..09c15e6b60 100644
--- a/qom/cpu.c
+++ b/qom/cpu.c
@@ -254,7 +254,7 @@ static void cpu_class_init(ObjectClass *klass, void *data)
     k->gdb_read_register = cpu_common_gdb_read_register;
     k->gdb_write_register = cpu_common_gdb_write_register;
     dc->realize = cpu_common_realizefn;
-    dc->no_user = 1;
+    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
 }
 
 static const TypeInfo cpu_type_info = {