Re: [Qemu-devel] [PATCH 3/4] qemu-config: Add -drive fd and opaque options

[Corey Bryant <coreyb@linux.vnet.ibm.com>]

On 10/05/2012 02:51 PM, Eric Blake wrote:
> On 10/05/2012 12:44 PM, Corey Bryant wrote:
>> Yes, this makes more sense.  I'd like to mirror the add-fd QMP command
>> as much as possible:
>>
>> { 'command': 'add-fd', 'data': {'*fdset-id': 'int', '*opaque': 'str'},
>>    'returns': 'AddfdInfo' }
>>
>> So maybe we can make it:
>>
>> -add-fd fd=24,fdset-id=1,opaque="rdonly" -add-fd
>> fd=25,fdset-id=1,opaque="rdwr"
>
> Sounds better.  Note that while fdset-id is optional in QMP, I think it
> needs to be mandatory on the CLI (you're telling qemu to use an
> inherited fd, but unless you know what set that fd belongs to, you can't
> then refer to that fd elsewhere on the command line, and unlike the QMP
> command, there is no venue for QMP to tell you what set was autocreated).
>

I agree the fdset ID should be mandatory on the command line so we can 
link up other commands like '-drive file=/dev/fdset/nnn' where nnn is 
the fdset ID.

> Bike-shedding: I think the command line can be slightly shorter with:
>
> -add-fd fd=24,set=1,opaque=...
>

Sure, I have no problem with shortening it.

-- 
Regards,
Corey Bryant

> with no real loss in information (that is, s/fdset-id/set/), since our
> command lines are already quite long.  But going longhand to match QMP
> doesn't hurt my feelings (libvirt will be automating this all anyway, so
> I won't really be typing it by hand).
>