Re: [Qemu-devel] [PATCH v8 13/13] dump: add 'query-dump-guest-memory-capability' command

[Paolo Bonzini <pbonzini@redhat.com>]

Il 10/02/2014 23:02, Laszlo Ersek ha scritto:
> On 02/10/14 20:10, Luiz Capitulino wrote:
>> On Tue, 28 Jan 2014 14:22:06 +0800
>> qiaonuohan <qiaonuohan@cn.fujitsu.com> wrote:
>>
>>> 'query-dump-guest-memory-capability' is used to query whether option 'format'
>>> is available for 'dump-guest-memory' and the available format. The output
>>> of the command will be like:
>>>
>>> -> { "execute": "query-dump-guest-memory-capability" }
>>> <- { "return": {
>>>         "format-option": "optional",
>>>         "capabilities": [
>>>             {"available": true, "format": "elf"},
>>>             {"available": true, "format": "kdump-zlib"},
>>>             {"available": true, "format": "kdump-lzo"},
>>>             {"available": true, "format": "kdump-snappy"}
>>>         ]
>>>     }
>>
>> I don't want to hold this series anymore, this series is long and I know it
>> took you and Laszlo's a long time to get it right. On the other hand we can't
>> allow every single command to have its own introspection protocol.
>>
>> I think I'm fine accepting this one now, as long as it's fine for libvirt
>> too. Eric, can you confirm this please?
>
> We discussed this before, and Eric participated. In fact the custom
> introspection was one of his recommendations.
>
> http://thread.gmane.org/gmane.comp.emulators.qemu/221270/focus=246650
>
> (Which I agreed with because it would give us the most independence.)
>
> Of course I'm not trying to imply that this one specific interface will
> doubtlessly serve all of libvirt's needs wrt. the kdump feature. We
> certainly need Eric to sign off on that.

I think the justification here is that even if you defined an Enum for 
['elf','kdump-zlib', 'kdump-lzo', 'kdump-snappy'], it would not be 
enough to describe which values were compiled in (as opposed to 
supported by the particular QEMU version).

However, I don't see the point in having the "format-option" field. 
What about:

-> { "execute": "query-dump-guest-memory-capabilities" }
<- { "return": { "formats":
           ["elf", "kdump-zlib", "kdump-lzo", "kdump-snappy"] }

Paolo