From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34586) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDGWE-00086l-HA for qemu-devel@nongnu.org; Wed, 15 Jun 2016 15:30:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bDGWA-0005e9-Ar for qemu-devel@nongnu.org; Wed, 15 Jun 2016 15:30:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52321) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDGWA-0005dy-2X for qemu-devel@nongnu.org; Wed, 15 Jun 2016 15:30:26 -0400 Date: Wed, 15 Jun 2016 20:30:20 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20160615193019.GB7300@work-vm> References: <1451921002-8263-2-git-send-email-stefanb@us.ibm.com> <20160120150041.GC13215@redhat.com> <201601201532.u0KFW2q2019737@d03av03.boulder.ibm.com> <20160120154657.GF13215@redhat.com> <569FADC7.7060301@linux.vnet.ibm.com> <20160120162220.GH13215@redhat.com> <20160121113632.GC2446@work-vm> <57FA3A002D66E049AA7792D931B894C7060F5494@MOKSCY3MSGUSRGB.ITServices.sbc.com> <945CA011AD5F084CBEA3E851C0AB28894B8C3A14@SHSMSX101.ccr.corp.intel.com> <575E92DB.3080904@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <575E92DB.3080904@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: "Xu, Quan" , "BICKFORD, JEFFREY E" , Stefan Berger , "mst@redhat.com" , "qemu-devel@nongnu.org" , "silviu.vlasceanu@gmail.com" , "hagen.lauer@huawei.com" , "SHIH, CHING C" , "SERBAN, CRISTINA" , "Daniel P. Berrange" * Stefan Berger (stefanb@linux.vnet.ibm.com) wrote: > On 05/31/2016 09:58 PM, Xu, Quan wrote: > > On Wednesday, June 01, 2016 2:59 AM, BICKFORD, JEFFREY E wrote: > > > > * Daniel P. Berrange (berrange@redhat.com) wrote: > > > > > On Wed, Jan 20, 2016 at 10:54:47AM -0500, Stefan Berger wrote: > > > > > > On 01/20/2016 10:46 AM, Daniel P. Berrange wrote: > > > > > > > On Wed, Jan 20, 2016 at 10:31:56AM -0500, Stefan Berger wrote: > > > > > > > > "Daniel P. Berrange" wrote on 01/20/2016 > > > > > > > > 10:00:41 > > > > > > > > AM: > > > > > > > > > > > > > > > > > > > > > > > > > process at all - it would make sense if there was a single > > > > > > > > > swtpm_cuse shared across all QEMU's, but if there's one per > > > > > > > > > QEMU device, it feels like it'd be much simpler to just have > > > > > > > > > the functionality linked in QEMU. That avoids the problem > > > > > > > > I tried having it linked in QEMU before. It was basically rejected. > > > > > > > I remember an impl you did many years(?) ago now, but don't > > > > > > > recall the results of the discussion. Can you elaborate on why it > > > > > > > was rejected as an approach ? It just doesn't make much sense to > > > > > > > me to have to create an external daemon, a CUSE device and comms > > > > > > > protocol, simply to be able to read/write a plain file containing > > > > > > > the TPM state. Its massive over engineering IMHO and adding way > > > > > > > more complexity and thus scope for failure > > > > > > The TPM 1.2 implementation adds 10s of thousands of lines of code. > > > > > > The TPM 2 implementation is in the same range. The concern was > > > > > > having this code right in the QEMU address space. It's big, it can > > > > > > have bugs, so we don't want it to harm QEMU. So we now put this > > > > > > into an external process implemented by the swtpm project that > > > > > > builds on libtpms which provides TPM 1.2 functionality (to be > > > > > > extended with TPM 2). We cannot call APIs of libtpms directly > > > > > > anymore, so we need a control channel, which is implemented through > > > ioctls on the CUSE device. > > > > > Ok, the security separation concern does make some sense. The use of > > > > > CUSE still seems fairly questionable to me. CUSE makes sense if you > > > > > want to provide a drop-in replacement for the kernel TPM device > > > > > driver, which would avoid ned for a new QEMU backend. If you're not > > > > > emulating an existing kernel driver ABI though, CUSE + ioctl is > > > > > feels like a really awful RPC transport between 2 userspace processes. > > > > While I don't really like CUSE; I can see some of the reasoning here. > > > > By providing the existing TPM ioctl interface I think it means you can > > > > use existing host-side TPM tools to initialise/query the soft-tpm, and > > > > those should be independent of the soft-tpm implementation. > > > > As for the extra interfaces you need because it's a soft-tpm to set it > > > > up, once you've already got that ioctl interface as above, then it > > > > seems to make sense to extend that to add the extra interfaces needed. > > > > The only thing you have to watch for there are that the extra > > > > interfaces don't clash with any future kernel ioctl extensions, and > > > > that the interface defined is generic enough for different soft-tpm > > > implementations. > > > > > > > Dave > > > > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK > > > > > > Over the past several months, AT&T Security Research has been testing the > > > Virtual TPM software from IBM on the Power (ppc64) platform. > > What about x86 platform? > > > > > Based on our > > > testing results, the vTPM software works well and as expected. Support for > > > libvirt and the CUSE TPM allows us to create VMs with the vTPM functionality > > > and was tested in a full-fledged OpenStack environment. > > > > > Cool.. > > > > > We believe the vTPM functionality will improve various aspects of VM security > > > in our enterprise-grade cloud environment. AT&T would like to see these > > > patches accepted into the QEMU community as the default-standard build so > > > this technology can be easily adopted in various open source cloud > > > deployments. > > Stefan: could you update status about this patch set? I'd really appreciate your patch.. > > What do you mean by 'update status'. It's pretty much still the same as > before. > > https://github.com/stefanberger/qemu-tpm/tree/v2.6.0+tpm > > > The implementation of the swtpm that I use for connecting QEMU to now has > more interface choices. There's the existing CUSE + ioctl for data and > control channel or any combination of TCP and Unix sockets for data and > control channel. The libvirt based management stack I built on top of QEMU > with vTPM assumes QEMU using the CUSE interface. So what was the multi-instance vTPM proxy driver patch set about? Dave > > Stefan > > > > > > -Quan > > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK