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

[Peter Maydell]

On Mon, 23 Jan 2023 at 20:08, Thomas Huth <thuth@redhat.com> wrote:
>
> On 23/01/2023 19.07, Matwey V. Kornilov 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?
>
> It's doable on some targets, e.g. m68k. avr seems to be working, too:
>
> - You can specify a CPU with the "-cpu" command line option
>    (use "-cpu help" for a list)
>
> - You can specify a RAM region with the "-m" command line option
>    (it will be created at address 0)

Oh, I didn't realize 'none' supported the -cpu and -m options...

I suspect the limit of this thing will be the point at which
you wanted a device like a UART or an interrupt controller.

-- PMM