Re: [Qemu-devel] [PATCH 0/5] Platform device support

[Paolo Bonzini <pbonzini@redhat.com>]

Il 04/06/2014 14:28, Alexander Graf ha scritto:
>
> But do we need that level of complexity for normal devices usually? In a
> normal platform world (SoCs, PV machines) we have a flat memory layout we
> can plug our device memory into. We also have a flat IRQ model where we
> can plug our device IRQs into.
>
> So the idea for platform devices arose. A platform device is really just a
> device that exposes its qemu_irq slots and memory regions to the world.
>
> That allows us to write machine specific code that maps a platform device
> wherever the machine thinks fits nicely. It also allows that same machine
> to generate a device tree entry for platform devices easily, as it is fully
> aware of the interrupt lines and places it was mapped to.
>
> A device (read: user) may or may not explictly request to be mapped at a
> specific IRQ and/or memory address. If no explicit mapping is requested,
> platform devices can get mapped at convenient places by the machine.
>
> The actual pressing issue this solves is that today it's impossible to spawn
> serial ports from the command line. With this patch set, it's possible to
> do so. But it lays the groundwork for much more...

I have more than a suspect that you and Peter Crosthwaite are trying to 
do the same.  I hope that memory region QOMification can get into 2.1, 
that can be a starting point that we can work from.

Paolo