Message-ID: <Z8olhSPAX0cyten5@kernel.org>
Date: Fri, 7 Mar 2025 00:45:25 +0200
From: Jarkko Sakkinen <jarkko@...nel.org>
To: Stuart Yoder <stuart.yoder@....com>
Cc: linux-integrity@...r.kernel.org, peterhuewe@....de, jgg@...pe.ca,
	sudeep.holla@....com, rafael@...nel.org, lenb@...nel.org,
	linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 0/5] Add support for the TPM FF-A start method

On Wed, Mar 05, 2025 at 11:36:06AM -0600, Stuart Yoder wrote:
> Firmware Framework for Arm A-profile (FF-A) is a messaging framework
> for Arm-based systems, and in the context of the TPM CRB driver is used
> to signal 'start' to a CRB-based TPM service which is hosted in an
> FF-A secure partition running in TrustZone.
> 
> These patches add support for the CRB FF-A start method defined
> in the TCG ACPI specification v1.4 and the FF-A ABI defined
> in the Arm TPM Service CRB over FF-A (DEN0138) specification:
> https://developer.arm.com/documentation/den0138/latest/
> 
> The first patch adds an FF-A driver to handle the FF-A messaging when
> communicating with a CRB-based TPM secure partition built on FF-A.
> The driver is probed when the TPM secure partition is discovered by
> the Linux FF-A infrastructure.
> 
> The second patch consolidates the check for idle support in the CRB
> driver to one place.
> 
> The third patch defines the new ACPI start method enumeration for
> CRB over FF-A.
> 
> The fourth patch adds support for the FF-A ACPI start method to
> the TPM crb driver.
> 
> The fifth patch adds documentation explaining how the CRB driver
> and FF-A relate.
> 
> Version 6
> -in tpm_crb removed unnecessary brackets from if statement and
>  fixed comment style
> -noticed and fixed bug in patch 2, polarity of return value
>  from tpm_crb_has_idle() was wrong and wasn't caught in past
>  testing
> -added Reviewed-by tag to patches 2 and 5
> 
> Version 5
> -tpm_ffa_crb patch: removed module version
> -tpm_ffa_crb patch: fixed module description
> -tpm_ffa_crb patch: updated comment on mutex declaration
> -reworded commit message for patch 2 as per Jarkko's 
>  suggestion
> -added Acked tag by Sudeep to patch 1 for FF-A changes 
> -added Reviewed-by tag to patches 3 and 4
> 
> Version 4
> -fix warning from kernel test robot in patch 1
> -fix warnings from checkpatch.pl --strict
> -clean up unnecessary parenthesis usage
> -update variable declaration to be reverse tree order
> -document exported functions in tpm_crb_ffa driver
> -remove unnecessary author and maintainer info in tpm_crb_ffa driver
> -fix declaration of variables to be in reverse tree order
> 
> Version 3
> -changed prefixes used throughout patch series to tpm_crb_ffa*
> 
> Version 2
> -updates to cover letter to define FF-A
> -added new patch with documentation
> -created pull request in ACPIA and added link to the patch
>  updating actbl3.h
> -added tpm_ prefix to the FF-A CRB driver
> 
> Stuart Yoder (5):
>   tpm_crb: implement driver compliant to CRB over FF-A
>   tpm_crb: clean-up and refactor check for idle support
>   ACPICA: add start method for Arm FF-A
>   tpm_crb: add support for the Arm FF-A start method
>   Documentation: tpm: add documentation for the CRB FF-A interface
> 
>  Documentation/security/tpm/tpm_ffa_crb.rst |  65 ++++
>  drivers/char/tpm/Kconfig                   |   9 +
>  drivers/char/tpm/Makefile                  |   1 +
>  drivers/char/tpm/tpm_crb.c                 | 105 +++++--
>  drivers/char/tpm/tpm_crb_ffa.c             | 348 +++++++++++++++++++++
>  drivers/char/tpm/tpm_crb_ffa.h             |  25 ++
>  include/acpi/actbl3.h                      |   1 +
>  7 files changed, 535 insertions(+), 19 deletions(-)
>  create mode 100644 Documentation/security/tpm/tpm_ffa_crb.rst
>  create mode 100644 drivers/char/tpm/tpm_crb_ffa.c
>  create mode 100644 drivers/char/tpm/tpm_crb_ffa.h
> 
> -- 
> 2.34.1
> 

OK, I guess we can apply this? Any objections? I'll apply
this over the weekend if nothing alarming comes up.

Thanks for the effort and patience!

BR, Jarkko

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