From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47520) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aoEux-000619-Lx for qemu-devel@nongnu.org; Thu, 07 Apr 2016 14:44:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aoEur-0008Jx-Ng for qemu-devel@nongnu.org; Thu, 07 Apr 2016 14:44:34 -0400 Received: from lists.gnu.org ([2001:4830:134:3::11]:42402) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aoEur-0008Jt-Kh for qemu-devel@nongnu.org; Thu, 07 Apr 2016 14:44:29 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47520) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aoEua-000619-6F for qemu-devel@nongnu.org; Thu, 07 Apr 2016 14:44:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aoEuO-0008Bo-IS for qemu-devel@nongnu.org; Thu, 07 Apr 2016 14:44:05 -0400 Received: from lists.gnu.org ([2001:4830:134:3::11]:43461) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aoEuO-0008Bk-FB for qemu-devel@nongnu.org; Thu, 07 Apr 2016 14:44:00 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56276) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aoECc-0002g4-13 for qemu-devel@nongnu.org; Thu, 07 Apr 2016 13:58:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aoDZS-0000Xq-Df for qemu-devel@nongnu.org; Thu, 07 Apr 2016 13:18:21 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48369) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aoDZS-0000Xk-7X for qemu-devel@nongnu.org; Thu, 07 Apr 2016 13:18:18 -0400 Date: Thu, 7 Apr 2016 20:18:13 +0300 From: "Michael S. Tsirkin" Message-ID: <20160407201655-mutt-send-email-mst@redhat.com> References: <1460043243-6198-1-git-send-email-mst@redhat.com> <5706897C.70203@redhat.com> <20160407192713-mutt-send-email-mst@redhat.com> <20160407165516.GS2060@HEDWIG.INI.CMU.EDU> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160407165516.GS2060@HEDWIG.INI.CMU.EDU> Subject: Re: [Qemu-devel] [PATCH v2] fw_cfg: RFQDN rules, documentation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Gabriel L. Somlo" Cc: Laszlo Ersek , qemu-devel@nongnu.org, Gerd Hoffmann , Markus Armbruster , Paolo Bonzini On Thu, Apr 07, 2016 at 12:55:16PM -0400, Gabriel L. Somlo wrote: ... > > > question is, I think: > > > > > > Should we allow QEMU firmware developers to create special settings, > > > to be populated manually by their end-users, that the guest kernel > > > would be prevented from seeing? > > > > Exactly. > > > > > I don't think so. Namely, in practice, new firmware settings (that are > > > to be populated manually by users) will go under "opt/org.seabios/" and > > > "opt/org.tianocore.edk2.ovmf/". I couldn't care less if a guest kernel > > > user looks at such files. After all, the names *explicitly carry* the > > > RFQDN of the intended consumer. If a user violates it, that's his > > > problem. (It may become the problem of his downstream users too, but > > > that's the same thing.) > > > > > > So, as long as I understood your question right, I don't think it's > > > necessary. > > > > It's not a question we need to ask ourselves as hardware/qemu designers. > > It's a question for the guest kernel - once that exposes > > interfaces to applications, it has to maintain them forever. > > And that's why IMHO it's cleaner for that interface to be: > > /sys/firmware/qemu-fw-cfg/by-name//[key|name|raw|size] > > I really don't think any particular instance of could > reasonably be called an "interface" (and therefore create expectations > of its continued presence forever), or can it ? > > Thanks, > --Gabriel Generally it's an interface if userspace relies on it. > > This is unlike firmware interfaces - if these are updated > > together with firmware, you do not need to maintain > > old ones.