From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52122) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YVliV-0002uR-FF for qemu-devel@nongnu.org; Wed, 11 Mar 2015 14:50:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YVliS-0004FC-4R for qemu-devel@nongnu.org; Wed, 11 Mar 2015 14:50:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55270) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YVliR-0004Er-T9 for qemu-devel@nongnu.org; Wed, 11 Mar 2015 14:50:48 -0400 Message-ID: <55008E80.50907@redhat.com> Date: Wed, 11 Mar 2015 19:50:40 +0100 From: Laszlo Ersek MIME-Version: 1.0 References: <20150311152758.GU1832@HEDWIG.INI.CMU.EDU> In-Reply-To: <20150311152758.GU1832@HEDWIG.INI.CMU.EDU> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] fw_cfg specification ? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Gabriel L. Somlo" , qemu-devel@nongnu.org Cc: jordan.l.justen@intel.com, gleb@cloudius-systems.com On 03/11/15 16:27, Gabriel L. Somlo wrote: > Hi, > > I'm looking for the closest thing to an official spec for qemu's > fw_cfg device, and so far I have found this: > > http://lists.gnu.org/archive/html/qemu-devel/2011-04/msg00238.html > > but it apparently never got committed to qemu (any idea why not?). Must have fallen through the cracks. (Just speculating; in April 2011 I had been with RH for less than half a year, and learning Xen. :)) > Googling around didn't get me much further than that. > > Is there anything better or more up to date floating around out > there somewhere ? I won't say "better", but it is "committed": check "Documentation/devicetree/bindings/arm/fw-cfg.txt" in the kernel tree. It is intentionally vague on the set of keys and fw_cfg files that qemu provides, because that's a moving target. You can only rely on the qemu source for those. Also, I updated Gleb's email address in the CC: header. If you have a ton of time, you could try documenting fw_cfg yourself, but as I said, it's a moving target, so the description would either become stale quickly, or require people to keep it in sync with the source all the time. Updating documentation sucks *hard*. (At one point I had also started a text file like Jordan's, but I didn't even get as far as posting it anywhere; I just gave up.) Thanks Laszlo