From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43001) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aqIXP-0008Kw-Mm for qemu-devel@nongnu.org; Wed, 13 Apr 2016 07:00:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aqIXM-0004N3-G0 for qemu-devel@nongnu.org; Wed, 13 Apr 2016 07:00:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45842) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aqIXM-0004Mv-AT for qemu-devel@nongnu.org; Wed, 13 Apr 2016 07:00:44 -0400 Date: Wed, 13 Apr 2016 14:00:39 +0300 From: "Michael S. Tsirkin" Message-ID: <20160413135342-mutt-send-email-mst@redhat.com> References: <1460102035-15972-1-git-send-email-mst@redhat.com> <87twjcvz7o.fsf@dusky.pond.sub.org> <20160409200141-mutt-send-email-mst@redhat.com> <8760voo18x.fsf@dusky.pond.sub.org> <20160411142509-mutt-send-email-mst@redhat.com> <8760vlq3yg.fsf@dusky.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8760vlq3yg.fsf@dusky.pond.sub.org> Subject: Re: [Qemu-devel] [PATCH v3] fw_cfg: RFQDN rules, documentation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster Cc: Paolo Bonzini , "Gabriel L . Somlo" , Laszlo Ersek , qemu-devel@nongnu.org, Gerd Hoffmann On Wed, Apr 13, 2016 at 10:59:35AM +0200, Markus Armbruster wrote: > I have a hard time coming up with realistic unclean breakage. The issue is that Linux is now exposing fw cfg to userspace. So it's use is about to expand significantly. This is what I am trying to prevent: - in 2016, users build a guest using a path XXX outside opt. there's a warning on host, but it is not noticed. - in 2020, qemu starts using path XXX for internal purposes. - using guest from 2016 now breaks uncleanly on this new qemu since guest thinks it's talking to the external tool. -- MST