Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: [PATCH v2 3/3] tpm: vtpm_proxy: Add ioctl to request locality prepended to command | From | Stefan Berger <> | Date | Wed, 10 May 2017 09:20:14 -0400 |
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On 05/10/2017 08:47 AM, Jarkko Sakkinen wrote: > On Tue, May 09, 2017 at 11:49:05AM -0400, Stefan Berger wrote: >> On 05/08/2017 07:43 PM, Jarkko Sakkinen wrote: >>> On Thu, May 04, 2017 at 04:03:18PM -0400, Stefan Berger wrote: >>>> On 05/04/2017 02:40 PM, Jarkko Sakkinen wrote: >>>>> On Thu, May 04, 2017 at 07:14:27AM -0400, Stefan Berger wrote: >>>>>> On 05/04/2017 05:17 AM, Jarkko Sakkinen wrote: >>>>>>> On Wed, May 03, 2017 at 07:40:48PM -0400, Stefan Berger wrote: >>>>>>>> On 05/03/2017 06:37 PM, Jarkko Sakkinen wrote: >>>>>>>>> On Fri, Apr 28, 2017 at 09:02:18AM -0400, Stefan Berger wrote: >>>>>>>>>> Add an ioctl to request that the locality be prepended to every TPM >>>>>>>>>> command. >>>>>>>>> Don't really understand this change. Why locality is prenpended? >>>>>>>> Commands can be executed under locality 0-3 and for some commands it is >>>>>>>> important to know which locality a user may have chosen. How else should we >>>>>>>> convey that locality to the TPM emulator ? >>>>>>> Why this is not in the commit message? >>>>>>> >>>>>>> More scalable way to do this would be to have a set of vtpm proxy >>>>>>> commands. There could be a command for requesting and releasing >>>>>>> locality. That would be more clean. >>>>>> I would think that if someone wanted to use locality it's the client using >>>>>> /dev/tpm(rm)0 calling an ioctl or so and the vtpm proxy then merely passing >>>>>> that locality to the backend (TPM emulator). I suppose the intention is to >>>>>> support something like that following the addition of the new functions >>>>>> request_locality and release_locality? >>>>> What if we later on want to pass something else than locality to the >>>>> backend? How that will work out? >>>> 'push' more data in front. 'pop' off by recipient. We could wrap the command >>>> in some form. >>>> >>>> Stefan >>> I would find having a set of special commands cleaner. Prepending sounds >>> like a quick hack to me, not really something that should exist in the >>> mainline. >> Along the lines of this here? >> >> uint32_2 command >> uint32_2 totlength >> uint8_t locality >> uint8_t buffer[] <- the actual TPM command >> >> >> With a command code like VTPM_PROXY_CMD_TPM_CMD = 1. >> >> Stefan > That would break binary compability.
That's why I am adding that additional flag that allows a client to choose whether it wants the TPM command wrapped (or locality prepended) so that it knows what to expect from the driver. I don't think that breaks compatibility.
> > I would suggest allocating CC's backwards starting from 0xFFFFFFFF for > these control messages and send them in regular TPM command layout. A > bit similar idea as we have in the RM. > > /Jarkko >
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