Re: [qemu-s390x] [Qemu-devel] [PATCH v3 0/3] pc-dimm: factor out MemoryDevice

[David Hildenbrand]

>>> So this happens before any hotplug handler is called. Everything works
>>> just fine. What you don't like about this is the qdev_get_machine(). I
>>> also don't like it but in the short term I don't see any problem with
>>> it. It is resource allocation and not a "device plug" in the typical form.
>>
>> It's not qdev_get_machine() that's issue, it's layer violation,
>> where child device is allocating and mapping resources of one of its parents.
> 
> Quite simple: introduce a function at the machine where the child can
> "request" to get an address and "request" to plug/unplug a region.
> 
> Or what would be wrong about that?
> 

To extend on such an idea (looking at virtio_bus_device_plugged()
getting called from virtio realize functions)

Make the machine implement some new interface "MemoryDeviceManager".
>From virtio-mem/pmem realize, call a function like memory_device_plugged().

Lookup the machine (qdev_get_machine() or walk all the way up until we
find one that implements MemoryDeviceManager) and call
pre_plugged/plugged/unplugged.

We could hide that in a new device class TYPE_VIRTIO_MEMORY_DEVICE.

Opinions? Completely nonsense? :) Alternatives?

-- 

Thanks,

David / dhildenb