From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A1A0BC49ED9 for ; Thu, 12 Sep 2019 06:47:38 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 705B7208C2 for ; Thu, 12 Sep 2019 06:47:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 705B7208C2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:58682 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i8ItF-0000qI-Ah for qemu-devel@archiver.kernel.org; Thu, 12 Sep 2019 02:47:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45247) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i8Is2-0000Iu-R3 for qemu-devel@nongnu.org; Thu, 12 Sep 2019 02:46:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i8Is1-0008Ul-O8 for qemu-devel@nongnu.org; Thu, 12 Sep 2019 02:46:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45234) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i8Is1-0008UQ-Gx for qemu-devel@nongnu.org; Thu, 12 Sep 2019 02:46:21 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2303018C4260; Thu, 12 Sep 2019 06:46:20 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-117-142.ams2.redhat.com [10.36.117.142]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 336A41001B09; Thu, 12 Sep 2019 06:46:17 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id ABDF5113865F; Thu, 12 Sep 2019 08:46:15 +0200 (CEST) From: Markus Armbruster To: Alex =?utf-8?Q?Benn=C3=A9e?= References: <20190731160719.11396-1-alex.bennee@linaro.org> <87a7cty0tv.fsf@dusky.pond.sub.org> <875zm5yzgq.fsf@linaro.org> Date: Thu, 12 Sep 2019 08:46:15 +0200 In-Reply-To: <875zm5yzgq.fsf@linaro.org> ("Alex =?utf-8?Q?Benn=C3=A9e=22's?= message of "Fri, 06 Sep 2019 20:52:21 +0100") Message-ID: <87d0g6dnbc.fsf_-_@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.62]); Thu, 12 Sep 2019 06:46:20 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] TCG plugins and the GPL (was: [PATCH v4 00/54] plugins for TCG) X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , qemu-devel@nongnu.org, aaron@os.amperecomputing.com, cota@braap.org, Stefan Hajnoczi , bobby.prani@gmail.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Alex Benn=C3=A9e writes: > Markus Armbruster writes: [...] >> Please advise why TCG plugins don't undermine the GPL. Any proposal to >> add a plugin interface needs to do that. > > I'm not sure what we can say about this apart from "ask your lawyer". I'm not asking for a legal argument, I'm asking for a pragmatic one. > I'm certainly not proposing we add any sort of language about what > should and shouldn't be allowed to use the plugin interface. I find it > hard to see how anyone could argue code written to interface with the > plugin API couldn't be considered a derived work. What makes that so? Is writing a plugin without linking with QEMU code impractical? > There are two use cases I have in mind: > > The first is FLOSS developers writing interesting tools that can take > advantage of QEMU's control of the system to do experiments that are > tricky with other setups (Valgrind is limited to same-arch, Dynamo/Pin > are user-space only). I want these experiments to be easy to do without > having to keep hacking and re-hacking QEMU's core code. I would hope > QEMU developers would up-stream theirs into the QEMU source tree but I > can imagine academics will have open source code that will only ever sit > in their paper's repository. GPL'ed code that's not for upstream is 100% legitimate. > The other is users who currently maintain hacked up internal copies of > QEMU as a test bed for whatever piece of silicon they are brewing behind > closed doors. This code would never be distributed (hence never be a GPL > issue) Correct. We can't force anybody to distribute, and that's only proper. > and is generally kept private because it's IP sensitive > (e.g: experimenting with different cache models). If we can provide an > interface that allows them to keep their experiments private and > separate from changes to the core code then maybe apart from making > their lives a bit easier we will see some non-IP sensitive contributions > come back to the upstream. I live in hope ;-) I'm concerned about a third case: imlementing stuff as a plugin so you can distribute it with a GPL-incompatible license. Particularly pernicious when that stuff could be useful upstream. Are there any technical difficulties that could make distributing a plugins in binary form impractical?