Re: [Qemu-devel] [PATCH 1/2] QMP: Introduce commands doc

[Gerd Hoffmann]

  Hi,

> > > IMO, that's a serious bug. A slot is a user visible entity, both in
> > > that devices can only be hotplugged only as slots, not functions, and
> > > to determine the maximum number of devices you can add. If the user
> > > knows about it, qemu should too.
> > >
> > > We can easily represent a slot/device as a qbus with each of the
> > > functions as devices attached to it.

Point being?

> > Dunno. Gerd, what do you think?

There is a PCIDevice for each function.  PCIDevice->devfn (aka addr 
property) contains slot+function.  So hw/pci.c can figure which device 
functions belong to the same slot.  The pci hotplug code might need some 
fixes to handle multi-function devices correctly though (I guess this is 
the original issue?).  unplug is probably easy, plug might be harder. 
You have to plug-in all functions belonging to the slot first, then 
signal the guest that the slot has been hotplugged, which might need 
changes in the monitor protocol.

cheers,
  Gerd