Re: [Qemu-devel] [PATCH] qemu-options.hx: Improve documentation of chardev multiplexing mode

[Peter Maydell]

On 16 February 2016 at 17:57, Laszlo Ersek <address@hidden> wrote:
> On 02/16/16 18:02, Paolo Bonzini wrote:
>>
>>
>> On 16/02/2016 17:32, Laszlo Ersek wrote:
>>> I'm a big fan of muxing the stdio backend between the (human) monitor
>>> and the guest's serial console:
>>>
>>>   -chardev stdio,signal=off,mux=on,id=char0 \
>>>   -mon chardev=char0,mode=readline,default \
>>>   -serial chardev:char0 \
>>
>> Or just "-serial mon:stdio". :)
>
> For what reason on earth are these three *possible* at all to tie up
> into a single command line option?

Legacy convenience options. The muxing of the monitor and the
console way predates the implementation of chardev backends
and a generic mux.

QEMU's command line options are full of this kind of thing, where
we started off with a special purpose thingy that got a nice
short comprehensible option to turn it on and off, and then later
we got a general purpose facility with lots of orthogonal bells
and whistles. If you're lucky then the special-purpose legacy
option is exactly equivalent to some longer general purpose
option set; sometimes it isn't...

thanks
-- PMM