Re: [Qemu-devel] [PATCH RFC for-2.3 1/1] block: New command line option --no-format-probing

[Markus Armbruster]

Eric Blake <address@hidden> writes:

> On 03/20/2015 07:49 AM, Max Reitz wrote:
>
>>>>> Disabling probing entirely is a (hamfisted) way to ensure you always
>>>>> specify the format.
>>>>>
>
>>>
>>> I'd appreciate opinions on whether this is wanted for 2.3.  If it is,
>>> I'll post a version that actually works.
>> 
>> I don't have any objections because it won't break anything. But I guess
>> it'll be mostly up to whether Eric thinks that we'll need it right now.
>
> I'm totally in favor of the idea; it has no drawback to users that don't
> add it to the command line (so no chance of regression to existing
> command lines), and allows users that care to ensure that they are being
> secure.  And I can argue that this is a bug fix rather than a feature
> and therefore appropriate even in freeze (even though the bug has been a
> long-standing security hole, rather than a recent regression).
>
> If (a working version of) this makes it in 2.3, libvirt WILL use it in
> the next release.  It will take me less than 5 minutes to write up the
> libvirt patch, as long as the new option is advertised via
> query-command-line-options (which means that QMP introspection of the
> new option is a must for v2 :)

query-command-line-options covers only options using QemuOpts.  Fixing
that defect isn't in the cards for 2.3, which means I'll have to
implement it with QemuOpts.

Ways to do that:

* Stick it into an existing QemuOpts option.  Is there one that fits?
  --machine doesn't really fit.

* Create a new QemuOpts option for miscellaneous settings.  Would --misc
  format-probing=off be too ugly?  Got a better name than --misc?

  Existing miscellaneous non-QemeOpts options could then (in 2.4!)
  become sugar for something in this option group, thus become available
  with -readconfig.

Thoughts?