Re: [Qemu-devel] [PATCH 0/6] Device state visualization reloaded

[Jan Kiszka]

On 2011-09-06 18:09, Michael S. Tsirkin wrote:
> On Tue, Sep 06, 2011 at 10:51:26AM -0500, Anthony Liguori wrote:
>> On 09/06/2011 10:45 AM, Jan Kiszka wrote:
>>> On 2011-09-06 16:48, Michael S. Tsirkin wrote:
>>>> I'm afraid that won't be enough to stop people
>>>> scripting this command - libvirt accessed
>>>> HMP for years.
>>>>
>>>> On the other hand, no QMP command means e.g.
>>>> libvirt users don't get any benefit from this.
>>>>
>>>> What I think will solve these problems, for both HMP and QMP,
>>>> is an explicit 'debug_unstable' or 'debug_unsupported' command that will
>>>> expose all kind of debugging functionality making it
>>>> very explicit that it's an unsupported debugging utility.
>>>>
>>>> Proposed syntax:
>>>>
>>>> debug_unstable<subcommand>  <options>
>>>>
>>>> Example:
>>>>
>>>> debug_unstable device_show -all
>>>
>>> For HMP, this would needlessly complicate the user interface, nothing I
>>> would support. People scripting things on top of HMP are generally doing
>>> this on their own risk and cannot expect output stability.
>>>
>>> device_show is like info qtree: the output will naturally change as the
>>> emulated hardware evolves, information is added/removed, or we simply
>>> improve the layout. Recent changes on info network are an example for
>>> the latter.
>>
>> Yeah, I'm not worried about stability.  HMP commands that aren't
>> exposed as QMP commands are inherently unstable and should not be
>> scripted to.
> 
> They are also not accessible when using libvirt, right?
> Which means almost all cases I care about: debugging on my laptop
> I can easily attach with gdb and inspect state.

HMP passthrough or - I bet that's what you rather want - monitor
passthrough from gdb.

Jan

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