Re: [Qemu-devel] [PATCH V4 4/4] fw_cfg: insert fw_cfg file blobs via qemu cmdline

[Gerd Hoffmann <kraxel@redhat.com>]

  Hi,

> > I can't see a strong reasons to change things.  The docs clearly
> > recommend to use opt/ prefix to avoid conflicts.  That is fine IMHO.
> > 
> > I don't feel like enforcing that in code, being able to use something
> > else can be useful for debugging/testing purposes.  For example there
> > are some etc/* things seabios looks at which qemu has no support for.
> > One can also supply option roms with the new switch.
> > 
> > cheers,
> >   Gerd
> 
> Well isn't this exactly the problem?
> Once one does, then qemu gains same option rom and things break.

Yea, sure.  "testing/debugging purposes".  I don't mind if that breaks.
When developing stuff I do tricks which can break on
qemu/libvirt/whatever upgrade all the time for all kinds of reasons, for
example because libvirt doesn't support $new_hot_qemu_feature yet.

For production usage better don't do that and stick to the "opt/" prefix
recommendation.  If adding something outside opt/ turns out to be useful
outside testing/debugging we should add a proper qemu cmd line option
for that instead of suggesting users to fiddle with -fw_cfg.  No
question about that.

But I don't think we should break -fw_cfg usage as testing/debugging
tool by enforcing opt/ prefix.

cheers,
  Gerd