From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44058) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bCPe3-0002rg-Vt for qemu-devel@nongnu.org; Mon, 13 Jun 2016 07:03:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bCPdy-00050i-FX for qemu-devel@nongnu.org; Mon, 13 Jun 2016 07:03:02 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:46779) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bCPdy-00050L-6o for qemu-devel@nongnu.org; Mon, 13 Jun 2016 07:02:58 -0400 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u5DB0NEA068947 for ; Mon, 13 Jun 2016 07:02:57 -0400 Received: from e33.co.us.ibm.com (e33.co.us.ibm.com [32.97.110.151]) by mx0a-001b2d01.pphosted.com with ESMTP id 23gdxsuwvd-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 13 Jun 2016 07:02:57 -0400 Received: from localhost by e33.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 13 Jun 2016 05:02:56 -0600 References: <1451921002-8263-1-git-send-email-stefanb@us.ibm.com> <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> From: Stefan Berger Date: Mon, 13 Jun 2016 07:02:51 -0400 MIME-Version: 1.0 In-Reply-To: <945CA011AD5F084CBEA3E851C0AB28894B8C3A14@SHSMSX101.ccr.corp.intel.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Message-Id: <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: "Xu, Quan" , "BICKFORD, JEFFREY E" , Stefan Berger Cc: "mst@redhat.com" , "qemu-devel@nongnu.org" , "silviu.vlasceanu@gmail.com" , "hagen.lauer@huawei.com" , "SHIH, CHING C" , "SERBAN, CRISTINA" , "Dr. David Alan Gilbert" , "Daniel P. Berrange" 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. Stefan > > -Quan >