Remove qemu_append from the default configuration

[Wenzel]

The default configuration kafl.fuzzer configuration file specify a qemu_append option. https://github.com/IntelLabs/kafl.fuzzer/blob/master/kafl_fuzzer/common/config/default_settings.yaml#L27

This is only useful when fuzzing a kernel specified with --kernel. This setting is target specific and should be removed from the default config.

In fact when fuzzing a bios:

[il-steffen]

You need it when booting Linux, so I think the question is which one is the more common default?

We could also modify qemu.py to supply the append option only when --kernel is specified. The problem is that users may also have "qemu_base = -kernel xyz" or qemu_extra = "-bios foo"

Currently, there should be a kafl.yaml in the edk2 example folder that sets qemu_append option to empty string, and I think qemu.py is looking out for that.

[Wenzel]

Currently, there should be a kafl.yaml in the edk2 example folder that sets qemu_append option to empty string, and I think qemu.py is looking out for that.

Ideally this shouldn't be required.

We could also modify qemu.py to supply the append option only when --kernel is specified.

I think this is the right approach. 👍

The problem is that users may also have "qemu_base = -kernel xyz" or qemu_extra = "-bios foo"

Then we should redirect the user to the right config options for the fuzzer, they shouldn't use qemu_base or qemu_extra to specify either the kernel or the bios.

[Wenzel]

closed by #78