Re: What is the purpose for "none" machine?

[Peter Maydell]

On Mon, 23 Jan 2023 at 18:07, Matwey V. Kornilov
<matwey.kornilov@gmail.com> wrote:
>
> пн, 23 янв. 2023 г. в 21:02, Peter Maydell <peter.maydell@linaro.org>:
> >
> > On Mon, 23 Jan 2023 at 17:36, Matwey V. Kornilov
> > <matwey.kornilov@gmail.com> wrote:
> > > I am playing with qemu-system-avr currently.
> > > I see that there is an "empty machine" called "none" in
> > >
> > >      qemu-system-avr -M help
> > >
> > > list.
> > >
> > > Is it a real thing? I am failed to run any code with "none" machine.
> >
> > It is mostly for the benefit of management layer code (eg libvirt)
> > that wants to probe capabilities of QEMU[*], and secondarily used
> > in some of QEMU's own test suite.  The 'none' machine has no CPU,
> > no devices and no RAM, which is why you can't run any code on it.
>
> Thanks for the explanation. Is there a way to manually add CPU, RAM
> and other devices in the command line if 'none' is used?

For a CPU and RAM, for some architectures where there is hotplug
CPU and hotplug RAM support that might be possible (definitely
not for AVR!) but I'm not sure if it's supported as an intended
use case. For other devices, generally not.

thanks
-- PMM