On Wednesday, June 01, 2016 2:59 AM, BICKFORD, JEFFREY E <jb6...@att.com> wrote: > > * Daniel P. Berrange (berra...@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" <berra...@redhat.com> 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 / dgilb...@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.. -Quan