Re: Priority of -accel (was: [PATCH] tests/qemu-iotests: Update tests to recent desugarized -accel option)

[Paolo Bonzini]

On 07/01/20 11:03, Thomas Huth wrote:
>>  
>>  vm = QEMUMachine(iotests.qemu_prog)
>> -vm.add_args('-machine', 'accel=kvm:tcg')
>> +vm.add_args('-accel', 'kvm', '-accel', 'tcg')
> Looking at this, I wonder whether we really want the "-accel" option to
> prioritize the accelerators in the order of appearance? A lot of other
> CLI tools give the highest priority to the last parameter instead, e.g.
> "gcc -O3 -O1" compiles with -O1, and not with -O3.
> 
> Also I think it might be quite common that there are shell scripts which
> call "qemu-system-xxx -accel xyz $*" ... and if we don't invert the
> priorities of -accel, it will be impossible to override -accel in that
> case...

Hmm, it does match "-machine accel=kvm:tcg" and in general I think it's
more self-explanatory.  However, it is indeed less friendly to scripts.
 On one hand those could be changed to place "-accel xyz" after $* (or
better "$@"), on the other hand we could also add a priority option to
"-accel".  What do you think?

Paolo