Peter Xu <pet...@redhat.com> writes:
> On Tue, Mar 22, 2016 at 12:42:42PM -0600, Eric Blake wrote:
>> On 03/17/2016 09:27 PM, Peter Xu wrote:
>> > This patch adds the command "query-gic-capabilities" but not implemnet
>>
>> s/not implemnet/does not implement/
>
> Yep, again. Thanks.
>
>>
>> > it. The command is ARM-only. Return of the command is a list of
>> > GICCapability struct that describes all GIC versions that current QEMU
>> > and system support.
>> >
>> > Signed-off-by: Peter Xu <pet...@redhat.com>
>> > ---
>>
>> > +++ b/qapi-schema.json
>> > @@ -4156,3 +4156,14 @@
>> > 'data': { 'version': 'int',
>> > 'emulated': 'bool',
>> > 'kernel': 'bool' } }
>> > +
>> > +##
>> > +# @query-gic-capabilities:
>> > +#
>> > +# Return a list of supported GIC version capabilities.
>> > +#
>> > +# Returns: a list of GICCapability.
>> > +#
>> > +# Since: 2.6
>> > +##
>> > +{ 'command': 'query-gic-capabilities', 'returns': ['GICCapability'] }
>>
>> On the surface, this seems okay. As mentioned before, I would have
>> squashed 1 and 2 into a single patch. The GICCapability type is
>> extensible, and introspection is sufficient at seeing what the type is
>> currently capable of exposing.
>>
>> On the other hand...
>>
>> > +++ b/scripts/qapi.py
>> > @@ -46,6 +46,7 @@ returns_whitelist = [
>> > 'query-tpm-models',
>> > 'query-tpm-types',
>> > 'ringbuf-read',
>> > + 'query-gic-capability',
>>
>> ...it required a whitelist, because you are violating the usual
It doesn't :)
>> convention of returning a dict. If you DO need the whitelist, your
>> addition should have been kept sorted. But you don't need it, if you
>> would modify your QAPI to return a dict:
>>
>> { 'struct': 'GICCapabilitiesReturn',
>> 'data': { 'capabilities': ['GICCapability'] } }
>> { 'command': 'query-gic-capabilities',
>> 'returns': 'GICCapabilitiesReturn' }
>>
>> Yes, the dict has only a single key, and that key points to the same
>> list; but now you have future extensibility: in the future, we could
>> return any future global data as a sibling to the array, without having
>> to modify every element of the array to repeat redundant information.
>
> Yes, I think this is better solution. Will adopt this in next version.
As explained in my other message, do this only if query-gic-capabilities
truly needs it. There's plenty of precedence for returning a list of a
structured type.
> Thanks for the comments!
>
> -- peterx
