[Qemu-devel] Re: [PATCH] optionally specify vm stop message

[Jan Kiszka <jan.kiszka@siemens.com>]

Anthony Liguori wrote:
> Jan Kiszka wrote:
>> Anthony Liguori wrote:
>>  
>>>>  Also non zero reasons a handled differently by vm_stop. Don't know
>>>> why.
>>>>         
>>> It's an ugly hack for gdbstub.  It notifies gdb when a breakpoint
>>> occurs.  We have far too many state tracking mechanisms.  Anyway, gdb
>>> can pass something like VM_STOP_BP and that can be used to trigger the
>>> callback.
>>>     
>>
>> It's not only used for breakpoints but any stop condition that should be
>> reported to the gdb frontend (so far: EXCP_DEBUG and EXCP_INTERRUPT).
>> Not sure, though, how to deal with ENOSPC - it's not a guest fault, it's
>> a host problem. From that POV, gdb should not receive it.
>>   
> 
> We already have a vm_change_state_handler that is invoked whenever a
> guest starts running or stops running.  gdb should be able to use that
> and look at env->exception_index, no?

I don't think env->exception_index is set when you issue "stop" from the
monitor, e.g. Moreover, that would be an ugly (out-of-band) API as well.

Jan

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