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

["Gabriel L. Somlo" <gsomlo@gmail.com>]

On Mon, Jun 01, 2015 at 12:50:50PM +0200, Paolo Bonzini wrote:
> > Someone writes a tool using a specific path.
> > We then add same path upstream, script breaks.
> 
> Who cares.  We documented it.
> 
> >> One usecase of this feature is to avoid recompiling QEMU while playing
> >> with firmware.  If you cannot mimic QEMU's behavior (which is to add
> >> "etc/" files), the feature is pointless, or at least I totally cannot
> >> understand its purpose and I'm against merging it.
> > 
> > Confused.  Why does it produce the warning then?
> 
> Because someone else asked for it.  I cannot answer. :)
> 
> > If it's just for playing games, add a configure
> > switch to enable it, and disable by default.
> > Don't set traps for users.
> 
> What is for playing games?  What is the feature useful for, except for
> developers.

My interest in this is for its asynchronous, agent-less host->guest
communication capability. As such, I would like it to be available at
all times, not just in special builds after enabling a build-time
switch...

As for the (meta)policy aspect (i.e., warn vs. error-out when outside
"opt/"), I am happy to go with whatever consensus emerges from this
conversation. I get both sides' positions, but don't have enough
context to feel strongly either way myself... :)

Thanks much,
--Gabriel