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 [off-list ref] wrote:

quoted

From: Gabriel Somlo <somlo-D+Gtc/HYRWM@public.gmane.org>

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