From: Jorge Ramirez <jorge.ramirez@oss.qualcomm.com>
To: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Jorge Ramirez-Ortiz <jorge.ramirez@oss.qualcomm.com>,
peterhuewe@gmx.de, jgg@ziepe.ca, sumit.garg@oss.qualcomm.com,
linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org
Subject: Re: [PATCH v2 1/2] tpm: add OP-TEE transport core and a discrete TPM driver
Date: Wed, 11 Nov 2026 14:49:20 +0100 [thread overview]
Message-ID: <avRyYBpQcYx-xo9o@trex> (raw)
In-Reply-To: <avM0uIlZxZIga4dY@kernel.org>
On 10/11/26 17:14:00, Jarkko Sakkinen wrote:
> On Tue, Nov 10, 2026 at 03:19:08PM +0100, Jorge Ramirez-Ortiz wrote:
> > Some platforms place a real (discrete) TPM on a bus that only the secure
> > world can drive. OP-TEE owns that bus, so the normal world cannot reach
> > the chip directly; it instead exposes a mediator trusted application
> > that relays TPM2 commands. Add a driver that talks to that application
> > and presents the chip as a standard TPM2 character device, so the
> > normal-world TPM stack works unchanged.
> >
> > This is a separate driver from the firmware-TPM one rather than a reuse
> > of it. The TEE transport is the same and is shared through a common
> > core, but the device identity differs: the firmware TPM uses its own
> > application and a public-login session, whereas a discrete chip needs
> > its own application and is restricted to kernel access so that user
> > space and other applications cannot submit raw commands to it. Folding
> > both into one driver would also break on a platform that has both.
> >
> > Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez@oss.qualcomm.com>
>
> Looks pretty good. Did you check the Sashiko remark?
>
> https://sashiko.dev/#/patchset/20261110141923.3100770-1-jorge.ramirez%40oss.qualcomm.com
>
> Br, Jarkko
um, right, that is a bug correctly addressed by the ftpm implementation
(the shutdown callback needs to go in the core as well)
will post a v3. thanks!
next prev parent reply other threads:[~2026-11-11 13:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-10 14:19 [PATCH v2 0/2] tpm: OP-TEE transport core for discrete and firmware TPMs Jorge Ramirez-Ortiz
2026-11-10 14:19 ` [PATCH v2 1/2] tpm: add OP-TEE transport core and a discrete TPM driver Jorge Ramirez-Ortiz
2026-11-10 15:14 ` Jarkko Sakkinen
2026-11-11 13:49 ` Jorge Ramirez [this message]
2026-11-10 14:19 ` [PATCH v2 2/2] tpm_ftpm_tee: use the tpm_optee transport core Jorge Ramirez-Ortiz
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