Re: [PATCH 11/12] habanalabs/gaudi2: add tpm attestation info uapi

[Oded Gabbay]

On Tue, Jun 28, 2022 at 12:12 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Tue, Jun 28, 2022 at 11:51:48AM +0300, Oded Gabbay wrote:
> > On Tue, Jun 28, 2022 at 9:36 AM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> > >
> > > On Mon, Jun 27, 2022 at 11:26:19PM +0300, Oded Gabbay wrote:
> > > > From: Dani Liberman <dliberman@xxxxxxxxx>
> > > >
> > > > User will provide a nonce via the ioctl, and will retrieve
> > > > attestation data of the boot from the tpm, generated using given
> > > > nonce.
> > >
> > > Why not use the normal TPM api instead of a new/custom one?  Or is this
> > > not a "normal" TPM device?  If not, you should say what it really is.
> > >
> > > thanks,
> > >
> > > greg k-h
> >
> > Honestly, I'm not that knowledgeable about it. It is hidden behind our
> > firmware code. We just provide a communication method between the
> > userspace and the firmware, as the userspace can't interact directly
> > with the f/w. i.e. The driver is a transparent tunnel, it doesn't
> > interact with registers of the TPM device itself. The "real" driver is
> > in our firmware.
> >
> > So basically we just got definitions from the f/w how to fetch the
> > data from them and how to expose it to the user and that's it.
> >
> > What to do in this case ? Is this considered a "real" TPM ? I imagine
> > I won't be able to connect to a standard tpm driver in the kernel as
> > the h/w is not exposed to me.
>
> How is this hardware designed?  Is the TPM in here supposed to be a
> real TPM for userspace to use?  Or is this just a random hardware thing
> that you use to validate your device somehow and is not supposed to be a
> normal TPM as per the specification?
We will go talk to our h/w people to find out and I'll get back to you
about that.
In the meantime, I will remove this patch from the series so it won't
hold up the entire
support.

Thanks,
Oded
>
> thanks,
>
> greg k-h