Re: [Qemu-devel] device assignment for embedded Power

[Scott Wood]

On Fri, 1 Jul 2011 07:10:45 -0500
Anthony Liguori <address@hidden> wrote:

> I agree in principle but I think it should be done in a slightly 
> different way.
> 
> I think we ought to support composing a device by passthrough.  For 
> instance, something like:
> 
> [physical-device "mydev"]
> region[0].file = "/dev/mem"
> region[0].guest_address = "0x42232000"
> region[0].file_offset = "0x23423400"
> region[0].size = "4096"
> irq[0].guest_irq = "10"
> irq[0].host_irq = "10"
> 
> This should be independent of anything to do with device tree.  This 
> would be useful for x86 too to assign platform devices (like the HPET).

That's fine, as long as there's something layered on top of it for the case
where we do want to reference something in the device tree.  

However, we'll need to address the question of what it means to say "irq 10"
-- outside of PC-land there often isn't a global IRQ numberspace that isn't
a fiction created by some software layer.  Addressing this is one of the
device tree's strengths.

-Scott