From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57369) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cj79t-0004kd-CR for qemu-devel@nongnu.org; Wed, 01 Mar 2017 11:31:22 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cj79q-000543-P5 for qemu-devel@nongnu.org; Wed, 01 Mar 2017 11:31:21 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48928) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cj79q-00053S-GD for qemu-devel@nongnu.org; Wed, 01 Mar 2017 11:31:18 -0500 Date: Wed, 1 Mar 2017 16:31:04 +0000 From: "Daniel P. Berrange" Message-ID: <20170301163104.GJ10160@redhat.com> Reply-To: "Daniel P. Berrange" References: <20160615193019.GB7300@work-vm> <5761C092.5070702@linux.vnet.ibm.com> <20160616080520.GA2249@work-vm> <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> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20170301181146-mutt-send-email-mst@kernel.org> 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: "Michael S. Tsirkin" Cc: Stefan Berger , =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , Stefan Berger , "qemu-devel@nongnu.org" , "Dr. David Alan Gilbert" , "hagen.lauer@huawei.com" , "Xu, Quan" , "silviu.vlasceanu@gmail.com" , "SERBAN, CRISTINA" , "SHIH, CHING C" 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. QEMU's defined the vhost-user ABI/API and delegated impl to something else. With the vTPM stuff here, we've not got a pre-existing feature we need to deal with, so the biggest blocker wrt modularization does not exist. Given that I think having the vTPM impl modularized is highly desirable, as long as we can define a sane ABI/API between QEMU and the external piece. So I think anthony's point about not putting a vTPM impl in-process is still valid, and since Stefan's already done much of the work to achieve a modular design we should not go back to an in-process design now. > It doesn't look like userspace swtpm bits have a large community of > developers around it, and the only user appears to be QEMU, so depending > on that externally does not make sense, we should just have them > in-tree. This way we don't need to worry about versioning etc. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://entangle-photo.org -o- http://search.cpan.org/~danberr/ :|