Re: [libvirt] [Qemu-devel] fix/re-do query-command-line-options
Paolo Bonzini <pbonzini(a)redhat.com> writes:
Il 28/01/2014 10:36, Markus Armbruster ha scritto:
> I think the data you can usefully collect with this approach is
> approximately the data getopt_long()[*] gets: list of named command line
> options, and whether they take an argument.
>
> You can use this data to fill in options not covered by QemuOpts. This
> is a definite improvement.
>
> It still falls short of fully solving the command line introspection
> problem.
>
> However, I'm not into rejecting imperfect incremental improvements we
> can have now in favor of perfect solutions we can maybe have some day.
> Go right ahead with your incremental improvement!
It depends. If we can agree on the following:
(a) do not add non-QemuOpts options (we haven't for a while)
That would mean we can't ever add an option that doesn't take an
argument again.
However, we need to somehow stuff those into QemuOpts anyway, so
-readconfig / -writeconfig can cover them.
(b) document the QemuOpts schema for -acpitable, -smbios, -netdev,
-net. These options validate the options with OptsVisitor, so we could
do without QemuOpts schema, but we know the schema won't bitrot
because we never remove suboptions.
-device?
(c) do not add any more QemuOpts options without a schema, and use
-object instead.
Then:
(a) there is no need to cover non-QemuOpts options in
query-command-line-options. libvirt can treat them as crystallized.
Some options are undef #ifdef. That's actually a good idea, because it
permits finding out which options are available via command line
introspection.
Now, what if a non-QemuOpts option is under #ifdef? I haven't
checked... Even if there isn't one now, are we ready to give up the
ability to do that for good?
(b) documenting the schemata is not harder than what Amos proposed.
(c) schema inspection for objects remains a problem, but one that we
need to solve anyway so it doesn't affect query-command-line-options.
As long as we don't have such schema inspection, I'm rather reluctant to
reject alternative means to solve problems people have *now*.
Do you agree?
It depends :)