Re: [Qemu-devel] KVM call agenda for Tuesday 3

[Peter Maydell]

On 3 January 2012 01:14, Anthony Liguori <address@hidden> wrote:
> Let's separate out what a user *should* do from what a user *can* do.
>
> A user *should* have a command line syntax that reflects something that
> makes sense to them.  For instance, qemu-system-arm --machine beaglebone
>
> I don't really care what the SoC or CPU in my beaglebone is.  I just want to
> emulate one.
>
> But I do believe we want to make it possible for -device to create a CPU
> even when it doesn't make sense.

So there's a couple of things here that fall in the "can't do that" bin:

1. trying to instantiate more than one device which has a CPU in it
(eg the default one from the machine/SoC model, and the second one
from the -device my-soc command line argument). (Basic QEMU limitation.)

2. trying to replace an existing device in the machine model with a
different one which isn't connection-compatible with it. For instance,
in a fully QOM world, trying to run a beagle machine with (say) a 926
CPU should fail to instantiate, because the 926 CPU won't have the right
set of irq/gpio inputs and outputs that the beagle machine needs to
connect up to. (This is the QOM equivalent of trying to ram a 486
into a Pentium CPU socket.)

I don't think we even have syntax for 2 at the moment except for the
weird special case of "-cpu foo".

-- PMM