Re: [Qemu-devel] [RFC][PATCH 0/21] QEMU Object Model

[Paolo Bonzini]

On 07/27/2011 02:48 PM, Anthony Liguori wrote:
> So the idea here is that the PIC will multiplex a bunch of interrupts
>  into a single line?

Yes, but the device needs to know the interrupt number so it can expose
it through the enumerator interface.  So the configuration cannot be simply

   pic->irq[n] = tty->irq;

Logically, it's more similar to the ISA case, but I doubt the PIC 
distributes all interrupts to everyone in real hardware.

> Is the enumerator something that has an interface to devices where
> the devices hold this info?  Or is the enumerator just a bank of
> flash that's preprogrammed with fixed info?

The former, at least in theory.  Not sure if it also works that way in
real hardware, but that's the model it exposes and the way the Android
guys implemented it.

The device model provides hotplug support, so it is definitely not just 
flash.  Not sure again if this support is used in the hardware.

> At each phase, we also get significantly better modularity.

Fine, but when do we decide it's good enough to merge it?  And what if 
it turns out that it's not suitable for devices?  We unified some 
things, but we also dug ourselves in NIH when we could have used 
GObject.  (GObject definitely does not work for devices, but at least we 
don't need to write the infrastructure).

> My only real concern is how to attack the device layer incrementally.
> I don't think it's impossible but it requires careful thought.

No idea here, honestly. :)

Paolo