qemu/include/hw
Markus Armbruster 9940b2cfbc qdev: New qdev_new(), qdev_realize(), etc.
We commonly plug devices into their bus right when we create them,
like this:

    dev = qdev_create(bus, type_name);

Note that @dev is a weak reference.  The reference from @bus to @dev
is the only strong one.

We realize at some later time, either with

    object_property_set_bool(OBJECT(dev), true, "realized", errp);

or its convenience wrapper

    qdev_init_nofail(dev);

If @dev still has no QOM parent then, realizing makes the
/machine/unattached/ orphanage its QOM parent.

Note that the device returned by qdev_create() is plugged into a bus,
but doesn't have a QOM parent, yet.  Until it acquires one,
unrealizing the bus will hang in bus_unparent():

    while ((kid = QTAILQ_FIRST(&bus->children)) != NULL) {
        DeviceState *dev = kid->child;
        object_unparent(OBJECT(dev));
    }

object_unparent() does nothing when its argument has no QOM parent,
and the loop spins forever.

Device state "no QOM parent, but plugged into bus" is dangerous.

Paolo suggested to delay plugging into the bus until realize.  We need
to plug into the parent bus before we call the device's realize
method, in case it uses the parent bus.  So the dangerous state still
exists, but only within realization, where we can manage it safely.

This commit creates infrastructure to do this:

    dev = qdev_new(type_name);
    ...
    qdev_realize_and_unref(dev, bus, errp)

Note that @dev becomes a strong reference here.
qdev_realize_and_unref() drops it.  There is also plain
qdev_realize(), which doesn't drop it.

The remainder of this series will convert all users to this new
interface.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
Cc: Alistair Francis <alistair@alistair23.me>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200610053247.1583243-5-armbru@redhat.com>
2020-06-15 21:36:30 +02:00
..
acpi acpi: ged: rename event memory region 2020-06-12 10:17:06 -04:00
adc
arm arm/aspeed: Rework NIC attachment 2020-06-15 21:36:09 +02:00
audio
block block: Support providing LCHS from user 2019-10-31 11:47:11 -04:00
char hw/char/cadence_uart: add clock support 2020-04-30 15:35:41 +01:00
core hw/core: Restrict CpuClass::get_crash_info() to system-mode 2020-06-05 21:23:22 +02:00
cpu
cris etraxfs: remove PROP_PTR usage 2020-01-07 17:24:29 +04:00
display qom/object: Move Object typedef to 'qemu/typedefs.h' 2020-06-10 12:09:36 -04:00
dma hw/arm/bcm283x: Correct the license text 2020-03-23 17:22:30 +00:00
firmware
gpio nrf51: Fix last GPIO CNF address 2020-04-30 11:52:27 +01:00
hyperv vmbus: add infrastructure to save/load vmbus requests 2020-06-10 12:09:41 -04:00
i2c hw/arm/nrf51: Add NRF51_PERIPHERAL_SIZE definition 2020-05-11 11:05:11 +01:00
i386 hw/i386/vmport: Add support for CMD_GETHZ 2020-06-10 12:09:53 -04:00
ide hw/ide: Move MAX_IDE_DEVS define to hw/ide/internal.h 2020-03-17 12:22:36 -04:00
input hppa: add emulation of LASI PS2 controllers 2020-01-27 10:49:51 -08:00
intc hw/arm/bcm283x: Correct the license text 2020-03-23 17:22:30 +00:00
ipack
ipmi ipmi: Add support to customize OEM functions 2019-12-17 10:39:47 +11:00
isa acpi: add ISADeviceClass->build_aml() 2020-05-04 10:25:02 -04:00
kvm
lm32
m68k
mem hw/acpi/nvdimm: add a helper to augment SRAT generation 2020-06-09 11:17:59 -04:00
mips
misc hw/misc/empty_slot: Name the slots when created 2020-06-09 06:59:44 +02:00
net hw/net: Add Smartfusion2 emac block 2020-04-30 11:52:28 +01:00
nubus hw/m68k: add Nubus support 2019-10-28 19:06:47 +01:00
nvram fw_cfg: Migrate ACPI table mr sizes separately 2020-04-13 06:55:54 -04:00
pci pcie_root_port: Add hotplug disabling option 2020-03-08 09:18:29 -04:00
pci-bridge
pci-host hw/pci-host/q35: Remove unused includes 2020-03-09 15:59:31 +01:00
ppc pnv/psi: Correct the pnv-psi* devices not to be sysbus devices 2020-06-15 21:36:21 +02:00
rdma
riscv riscv: Fix type of SiFive[EU]SocState, member parent_obj 2020-06-15 21:36:21 +02:00
rtc rtc: add RTC_ISA_BASE 2020-05-04 10:25:02 -04:00
s390x s390x: pv: Fix KVM_PV_PREP_RESET command wrapper name 2020-06-05 17:13:11 +02:00
scsi qdev: Unrealize must not fail 2020-05-15 07:08:14 +02:00
sd hw/arm/allwinner: add SD/MMC host controller 2020-03-12 16:27:33 +00:00
semihosting semihosting: add qemu_semihosting_console_inc for SYS_READC 2020-01-09 11:41:29 +00:00
sh4
southbridge hw/ide: Do ide_drive_get() within pci_ide_create_devs() 2020-03-17 12:22:36 -04:00
sparc
ssi aspeed/smc: Add AST2600 timings registers 2019-12-16 10:46:34 +00:00
timer hw/timer/nrf51_timer: Display timer ID in trace events 2020-05-11 11:05:52 +01:00
tricore
unicore32
usb exec/cpu-common: Move MUSB specific typedefs to 'hw/usb/hcd-musb.h' 2020-06-12 11:20:15 -04:00
vfio vfio: Turn the container error into an Error handle 2019-10-04 18:49:18 +02:00
virtio virtio: add vhost-user-vsock base device 2020-06-12 10:17:06 -04:00
watchdog hw/watchdog: Implement full i.MX watchdog support 2020-05-21 20:00:18 +01:00
xen accel: Move Xen accelerator code under accel/xen/ 2020-06-10 12:09:56 -04:00
xtensa
boards.h hw: add compat machines for 5.1 2020-05-06 10:12:16 -04:00
clock.h hw/core/clock-vmstate: define a vmstate entry for clock state 2020-04-30 15:35:40 +01:00
elf_ops.h hw/elf_ops: Do not ignore write failures when loading ELF 2020-06-10 12:10:23 -04:00
fw-path-provider.h
hotplug.h
hw.h
ide.h hw/ide: Move MAX_IDE_DEVS define to hw/ide/internal.h 2020-03-17 12:22:36 -04:00
irq.h Revert "irq: introduce qemu_irq_proxy()" 2019-11-05 23:33:12 +01:00
loader-fit.h
loader.h hw/core/loader: Let load_elf() populate a field with CPU-specific flags 2020-01-29 19:28:52 +01:00
nmi.h hw/nmi: Fix the NMI() macro, based on INTERFACE_CHECK() 2020-02-28 14:57:19 -05:00
or-irq.h hw/core/or-irq: Increase limit of or-lines to 48 2020-01-23 16:34:15 +00:00
pcmcia.h
platform-bus.h
ptimer.h ptimer: Remove old ptimer_init_with_bh() API 2019-11-11 13:44:16 +00:00
qdev-clock.h qdev-clock: introduce an init array to ease the device construction 2020-04-30 15:35:40 +01:00
qdev-core.h qdev: New qdev_new(), qdev_realize(), etc. 2020-06-15 21:36:30 +02:00
qdev-dma.h
qdev-properties.h multifd: Add multifd-compression parameter 2020-02-28 09:24:43 +01:00
register.h hw/core/register: Add register_init_block8 helper. 2020-05-05 13:37:51 -07:00
registerfields.h hw/registerfields: Prefix local variables with underscore in macros 2020-05-27 11:23:07 -07:00
resettable.h hw/core: deprecate old reset functions and introduce new ones 2020-01-30 16:02:04 +00:00
stream.h hw/core: stream: Add an end-of-packet flag 2020-05-14 13:44:35 +02:00
sysbus.h sysbus: remove outdated comment 2020-01-07 16:06:59 +04:00
usb.h hw/usb: Move device-specific declarations to new 'hcd-musb.h' header 2020-06-12 11:20:14 -04:00
vmstate-if.h vmstate: add qom interface to get id 2020-01-06 18:41:32 +04:00