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

[Corey Bryant]

On 10/05/2012 02:30 PM, Eric Blake wrote:
> On 10/05/2012 12:25 PM, Blue Swirl wrote:
>> On Fri, Oct 5, 2012 at 6:07 PM, Corey Bryant <coreyb at linux.vnet.ibm.com> wrote:
>>> These new options can be used for passing drive file descriptors
>>> on the command line, instead of using the file option to specify
>>> a file name.
>>>
>>> These new command line options mirror the existing add-fd QMP
>>> command which allows an fd to be passed to QEMU via SCM_RIGHTS and
>>> added to an fd set.  The opaque option is also available with
>>> add-fd, and allows a free-form string to be stored in the fd set
>>> along with the fd.
>>>
>
>>> +            .name = "opaque",
>>
>> 'opaque' is not very descriptive and it's also not obvious (except
>> from the help text) that it's only interesting for file descriptors.
>> How about fd_name, fd_tag or fd_descr?
>
> Hmm, since opaque is per-fd in the existing monitor command, that means
> my proposal needs a slight modification to:
>
>   -fdset set=1,fd=24,opaque="rdonly",fd=25,opaque="rdwr"

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"

-- 
Regards,
Corey Bryant

>
> or some other way where we can specify multiple fds and multiple opaque
> strings per set.
>
> At any rate, this just proves that we need to nail down the command line
> implementation to something that is easy enough to use, before coding up
> something that locks us in to bad design.
>