Re: [Qemu-devel] Re: [PATCH 2/5] gdbstub: gdb pass-through qemu monitor support

[Jason Wessel <jason.wessel@windriver.com>]

Jan Kiszka wrote:
> Jason Wessel wrote:
>   
>> Maxim Gorbachyov wrote:
>>     
>>> On Mon, May 19, 2008 at 5:29 PM, Jason Wessel
>>> <jason.wessel@windriver.com> wrote:
>>>
>>> [cut]
>>>   
>>>       
>>>> Seems reasonable too, see newly attached patch.
>>>>
>>>> Obviously you need the new monitor patch applied prior to this one.
>>>> This patch was updated against the prior patch.
>>>>     
>>>>         
>>> It was noticed [by Jan Kiszka and me] that the output on the monitor
>>> console goes both to the local as well as the remote one - but only if
>>> you issue a command via gdb. When you type in the command locally (ie.
>>> on the qemu side), that output is not forwarded to the gdb frontend.
>>> Is this behavior desired?
>>>
>>>
>>>   
>>>       
>> That was certainly the intended behavior when I created the patch. 
>> There is no reason to feed the monitor output up to the debugger that
>> may or may not be attached.
>>     
>
> That's not what we were confused by.
>
>   
>>  The behavior could get altered to check if
>> the debugger is in the "continue" state and then send the information
>> from the monitor, but it seemed of little value to do so.
>>     
>
> Rather the contrary: What is the point of mirroring the output you see
> in gdb to the local monitor console?
>
>   

That happens to have little to do with the gdb implementation.  It is a
function of the monitor mux.  The monitor mux always writes out to all
the output channels automatically.   In the case of gdb sending input
for which you only want to receive the response it would be plausible to
add a "focus" parameter to the monitor mux code to indicate which
"channel" to send the output to.

The monitor mux could also be changed to simply shift the output focus
to the most recent place it received an input, and if the focus was -1
to start it would broadcast every where, the way it does today.  It is a
trivial enough change, if this is what you are looking for.

Jason.