[PATCH v3 1/4] firmware: introduce sysfs driver for QEMU's fw_cfg device

[Gabriel L. Somlo]

On Tue, Oct 06, 2015 at 10:54:42AM -0700, Andy Lutomirski wrote:
> On Sat, Oct 3, 2015 at 4:28 PM, Gabriel L. Somlo <somlo at cmu.edu> wrote:
> > From: Gabriel Somlo <somlo at cmu.edu>
> >
> > Make fw_cfg entries of type "file" available via sysfs. Entries
> > are listed under /sys/firmware/qemu_fw_cfg/by_key, in folders
> > named after each entry's selector key. Filename, selector value,
> > and size read-only attributes are included for each entry. Also,
> > a "raw" attribute allows retrieval of the full binary content of
> > each entry.
> >
> > This patch also provides a documentation file outlining the
> > guest-side "hardware" interface exposed by the QEMU fw_cfg device.
> >
> 
> What's the status of "by_name"?  There's a single (presumably
> incorrect) mention of it in a comment in this patch.
> 
> I would prefer if the kernel populated by_name itself rather than
> deferring that to udev, since I'd like to use this facility in virtme,
> and I'd like to use fw_cfg very early on boot before I even start
> udev.

"by_name" is added with patch 4/4 of the series, which I kept separate
due to the "To udev or not to udev" conversation from earlier. So far
I haven't yet figured out just HOW I'd set it up in udev, but it works
already if done in the kernel :)

Thanks,
--Gabriel