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Date: Tue, 7 Oct 2014 22:22:10 +0300
From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Stefan Berger <stefanb@linux.vnet.ibm.com>
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Subject: Re: [Ksummit-discuss] [TrouSerS-tech] TPM MiniSummit @ LinuxCon
 Europe
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On Tue, Oct 07, 2014 at 01:54:41PM -0400, Stefan Berger wrote:
> On 09/23/2014 12:42 PM, Andy Lutomirski wrote:
> >On Sep 22, 2014 2:07 AM, "Peter Huewe" <PeterHuewe@gmx.de> wrote:
> >>Hi,
> >>
> >>I would like to 'invite' all interested parties in a short TPM minisummit where we can discuss the following hot topics of the TPM subsystem over a beer or two:
> >>  - State of the TPM Subsystem
> >>  - De-/Initialization Mess
> >>  - Devm'ification
> >>  - Testing
> >>  - TPM 2.0 Support
> >>  - Dependencies / interaction with other subsystems (e.g. keyring / IMA)
> >>  - Status of old 1.1b TPM drivers, deprecation plans
> >>  - ...
> >>
> >I am unlikely to be there, but I have a feature request / food for thought:
> >
> >Using a mandatory userspace daemon (e.g. trousers) for TPM access
> >sucks.  Might it be possible to teach the kernel to handle context
> >save and restore and let multiple processes open the device at once?
> >Then a daemon wouldn't be necessary.
> 
> Why add the complexity of swapping of authenticated sessions and keys into
> the kernel if you can handle this in userspace? You need a library that is
> aware of the number of key slots and slots for sessions in the TPM and swaps
> them in at out when applications need them. Trousers is such a library that
> was designed to cope with the limitations of the device and make its
> functionality available to all applications that want to access it.

One justification might be that kernel is also using TPM? TrouSerS can
not manage session for kernel internal use.

>    Stefan

/Jarkko