Re: [Qemu-devel] [PATCH] null-machine: Add support for the "-kernel" parameter

[Peter Maydell <peter.maydell@linaro.org>]

On 27 February 2017 at 17:49, Thomas Huth <thuth@redhat.com> wrote:
> On 27.02.2017 14:16, Marcel Apfelbaum wrote:
>> Why do we need the "-kernel" parameter for the null-machine? I mean -
>> what are the use cases?
>
> Since it is now possible to instantiate a CPU and memory with the
> null-machine, you can use it as a simple instruction set simulator board
> now. Start QEMU with something like "-M none -cpu xxx -m 1G -S -s" and
> then connect a remote GDB to interact with the emulated CPU. This is
> e.g. useful for CPU models that do not have a matching emulated machine
> yet. Adding the possibility to use the "-kernel" parameter for this,
> too, would make things a little bit more comfortable on certain targets,
> since you then don't have to fiddle with the generic-loader device.

But it still won't do the expected magic -kernel does for you on x86
or ARM or..., so it's just confusing to use the same option. We have
a command line option for "just load the binary please", and that's
the generic-loader. If you think generic-loader's syntax is a bit
tedious you could argue for a convenience option that was syntactic
sugar for it (in the same way that -hda is sugar for -drive and
-device options), but that shouldn't be limited to the null-machine.

thanks
-- PMM