From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57082) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YQwAJ-0002NO-JJ for qemu-devel@nongnu.org; Thu, 26 Feb 2015 05:59:36 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YQwAA-0003bC-Le for qemu-devel@nongnu.org; Thu, 26 Feb 2015 05:59:35 -0500 Received: from mga14.intel.com ([192.55.52.115]:27211) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YQwAA-0003az-HB for qemu-devel@nongnu.org; Thu, 26 Feb 2015 05:59:26 -0500 Message-ID: <1424948135.21588.37.camel@mfleming-mobl1.ger.corp.intel.com> From: Matt Fleming Date: Thu, 26 Feb 2015 10:55:35 +0000 In-Reply-To: <54EEEB26.9060102@redhat.com> References: <1424806987-24790-1-git-send-email-somlo@cmu.edu> <54ED0439.1030904@redhat.com> <1424904034.21588.19.camel@mfleming-mobl1.ger.corp.intel.com> <20150226011319.GA24405@foober.ini.cmu.edu> <54EEEB26.9060102@redhat.com> Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH 0/2] host->guest environment variables via fw_cfg List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Laszlo Ersek Cc: mdroth@linux.vnet.ibm.com, qemu-devel@nongnu.org, rjones@redhat.com, "Gabriel L. Somlo" On Thu, 2015-02-26 at 10:45 +0100, Laszlo Ersek wrote: > On 02/26/15 02:13, Gabriel L. Somlo wrote: > > For myself, I'm tempted to write a kernel driver to allow me to simply > > "cat /sys/firmware/fw_cfg/etc/guestinfo | grep '^key_name='" when I > > need to retrieve a guest environment variable. > > You might not need a kernel driver for this. If you have ioport access > (on x86), you can speak the fwcfg "protocol" directly. Personally, I'd be much happier to see this information exposed via /sys/firmware/fw_cfg, not least because that allows you to use the same tools on x86, arm64, etc.