Re: [PATCH v5 3/8] qapi: Restrict balloon-related commands to machine code

[Markus Armbruster]

Philippe Mathieu-Daudé <philmd@redhat.com> writes:

> On 9/14/20 1:21 PM, Markus Armbruster wrote:
>> David Hildenbrand <david@redhat.com> writes:
>> 
>>>> Am 14.09.2020 um 11:42 schrieb Philippe Mathieu-Daudé <philmd@redhat.com>:
>>>>
>>>> +Laurent and David
>>>>
>>>>> On 9/14/20 11:16 AM, Markus Armbruster wrote:
>>>>> Philippe Mathieu-Daudé <philmd@redhat.com> writes:
>>>>>
>>>>>> Only qemu-system-FOO and qemu-storage-daemon provide QMP
>>>>>> monitors, therefore such declarations and definitions are
>>>>>> irrelevant for user-mode emulation.
>>>>>>
>>>>>> Restricting the balloon-related commands to machine.json
>>>>>> allows pulling less declarations/definitions to user-mode.
>>>>>
>>>>> How this affects user mode is not obvious to (ignorant) me.  Can you
>>>>> provide a clue?
>>>>
>>>> I guess this was discussed with David at some point.
>>>>
>>>> Maybe the QMP commands are not exposed via HMP, making this
>>>> code unreachable?
>>>>
>>>> Anyhow user-mode binaries don't use the memory ballooning feature,
>>>> this is specific to system-mode emulation.
>>>>
>>>> Laurent/David, do you have some more trivial explanation?
>>>
>>> Agreed.
>>>
>>> No memory ballooning device -> no memory ballooning :)
>> 
>> I understand why user mode doesn't need device models.  What I don't
>> understand offhand is how balloon-related stuff in misc.json ends up
>> pulling "declarations/definitions to user-mode".  What exactly is being
>> pulled where before the series, and no more afterwards?
>> 
>> Is it just the code generated for the QAPI stuff you move, or is it
>> more?
>
> As of this series, this is only QAPI generated code.
> (code which pulls in unwanted declarations/definitions
> that should be poisoned, but we can't because of this).
>
> I didn't feel the need to enumerate what is removed from
> user-mode, because from the diff (and no link failure)
> I thought it was obvious. I can do, but that would be
> simply copy/pasting the QAPI changes.

Suggest to replace "pulling less declarations/definitions to user-mode"
by "pulling less QAPI-generated code into user-mode" in all the commit
messages.

> Part 3 start to remove things, but I kept that separated.

That's okay.