Hello,
I am working on vCPU Hotplug feature for ARM64 and I am in mid of understanding
some aspect of device_add/device_del interface of the QEMU.
Observations:
1. Any object initialised by qmp_device_add() gets into /machine/unattached
container. I traced the flow to code leg inside device_set_realized()
2. I could see the reverse qmp_device_del() expects the device to be in
/machine/peripheral container.
3. I could see any object initially added to unattached container did not had
their parents until object_add_property_child() was called further in the leg.
which effectively meant a new property was created and property table
populated and child was parented.
4. Generally, container /machine/peripheral was being used wherever
DEVICE(dev)->id was present and non-null.
Question:
1. Wanted to confirm my understanding about the use of having separate
containers like unattached, peripheral and anonymous.
2. At init time all the vcpus goes under *unattached* container. Now,
qmp_device_del() cannot be used to unplug them. I am wondering
if all the hotplug devices need to go under the *peripheral* container while
they are hotplugged and during object init time as well?
3. I could not see any device being place under *anonymous* container during
init time. What is the use of this container?
I would be thankful for your valuable insights and answers and help in
highlighting any gap in my understanding.
Thanks in anticipation!
Best Regards
Salil
