From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51525) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cj7rE-0005ne-3g for qemu-devel@nongnu.org; Wed, 01 Mar 2017 12:16:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cj7rA-0002mL-Py for qemu-devel@nongnu.org; Wed, 01 Mar 2017 12:16:08 -0500 Received: from mx1.redhat.com ([209.132.183.28]:41858) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cj7rA-0002lu-HZ for qemu-devel@nongnu.org; Wed, 01 Mar 2017 12:16:04 -0500 Date: Wed, 1 Mar 2017 19:16:01 +0200 From: "Michael S. Tsirkin" Message-ID: <20170301191459-mutt-send-email-mst@kernel.org> References: <20160616082517.GC11426@redhat.com> <5075d390-a1d1-b707-6b57-deb0154c2e37@linux.vnet.ibm.com> <20170301125414.GD10160@redhat.com> <05b271a3-4bf9-729b-d662-c9886951f26d@linux.vnet.ibm.com> <20170301181146-mutt-send-email-mst@kernel.org> <20170301163104.GJ10160@redhat.com> <20170301185414-mutt-send-email-mst@kernel.org> <1d155a66-8806-8792-b82d-4bebabcd4971@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1d155a66-8806-8792-b82d-4bebabcd4971@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [PATCH v5 1/4] Provide support for the CUSE TPM List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Berger Cc: "Daniel P. Berrange" , Stefan Berger , "qemu-devel@nongnu.org" , "Dr. David Alan Gilbert" , "SERBAN, CRISTINA" , =?iso-8859-1?Q?Marc-Andr=E9?= Lureau , "Xu, Quan" , "silviu.vlasceanu@gmail.com" , "hagen.lauer@huawei.com" , "SHIH, CHING C" On Wed, Mar 01, 2017 at 12:12:34PM -0500, Stefan Berger wrote: > On 03/01/2017 12:02 PM, Michael S. Tsirkin wrote: > > On Wed, Mar 01, 2017 at 04:31:04PM +0000, Daniel P. Berrange wrote: > > > On Wed, Mar 01, 2017 at 06:22:45PM +0200, Michael S. Tsirkin wrote: > > > > On Wed, Mar 01, 2017 at 09:50:38AM -0500, Stefan Berger wrote: > > > > > I had already proposed a linked-in version before I went to the out-of-process > > > > > design. Anthony's concerns back then were related to the code not being trusted > > > > > and a segfault in the code could bring down all of QEMU. That we have test > > > > > suites running over it didn't work as an argument. Some of the test suite are > > > > > private, though. > > > > Given how bad the alternative is maybe we should go back to that one. > > > > Same argument can be made for any device and we aren't making > > > > them out of process right now. > > > > > > > > IIMO it's less the in-process question (modularization > > > > of QEMU has been on the agenda since years and I don't > > > > think anyone is against it) it's more a code control/community question. > > > I rather disagree. Modularization of QEMU has seen few results > > > because it is generally a hard problem to solve when you have a > > > complex pre-existing codebase. I don't think code control has > > > been a factor in this - as long as QEMU can clearly define its > > > ABI/API between core & the modular pieces, it doesn't matter > > > who owns the module. We've seen this with vhost-user which is > > > essentially outsourcing network device backend impls to a 3rd > > > party project. > > And it was done precisely for community reasons. dpdk/VPP community is > > quite large and fell funded but they just can't all grok QEMU. They > > work for hardware vendors and do baremetal things. With the split we > > can focus on virtualization and they can focus on moving packets around. > > > > > > > QEMU's defined the vhost-user ABI/API and delegated > > > impl to something else. > > The vhost ABI isn't easy to maintain at all though. So I would not > > commit to that lightly without a good reason. > > > > It will be way more painful if the ABI is dictated by a 3rd party > > library. > > Who should define it? > No one. Put it in same source tree with QEMU and forget ABI stability issues. -- MST