linux-kernel - Re: [PATCH v8 0/4] tpm: Preserve TPM measurement log across kexec (ppc64)

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Date:   Fri, 11 Nov 2022 07:12:05 -0500
From:   Stefan Berger <stefanb@...ux.ibm.com>
To:     Coiby Xu <coxu@...hat.com>, Michael Ellerman <mpe@...erman.id.au>
Cc:     kexec@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, nayna@...ux.ibm.com,
        nasastry@...ibm.com, Baoquan He <bhe@...hat.com>
Subject: Re: [PATCH v8 0/4] tpm: Preserve TPM measurement log across kexec
 (ppc64)



On 11/10/22 21:21, Coiby Xu wrote:
> Hi Michael,
> 
> Could the PowerPC tree take this patch set which resolves a
> PowerVM/KVM-specific issue?

Michael has (shown me) an alternative approach that protects the already allocated memory to carry it across the kexec. This seems like a good and potentially better alternative, also from the perspective of the changes need, which is a lot less , and it's already used for other stuff as well.

    Stefan

> 
> On Thu, Sep 01, 2022 at 05:46:06PM -0400, Stefan Berger wrote:
>> The of-tree subsystem does not currently preserve the IBM vTPM 1.2 and
>> vTPM 2.0 measurement logs across a kexec on PowerVM and PowerKVM. This
>> series fixes this for the kexec_file_load() syscall using the flattened
>> device tree (fdt) to carry the TPM measurement log's buffer across kexec.
>>
>>   Stefan
>>
>> v8:
>> - Added Jarkko's, Coiby's, and Rob's tags
>> - Rebase on v6.0-rc3 that absorbed 2 already upstreamed patches
>>
>> v7:
>> - Added Nageswara's Tested-by tags
>> - Added back original comment to inline function and removed Jarkko's R-b tag
>>
>> v6:
>> - Add __init to get_kexec_buffer as suggested by Jonathan
>> - Fixed issue detected by kernel test robot
>>
>> v5:
>> - Rebased on 1 more patch that would otherwise create merge conflicts
>>
>> v4:
>> - Rebased on 2 patches that would otherwise create merge conflicts;
>>   posting these patches in this series with several tags removed so
>>   krobot can test the series already
>> - Changes to individual patches documented in patch descripitons
>>
>> v3:
>> - Moved TPM Open Firmware related function to drivers/char/tpm/eventlog/tpm_of.c
>>
>> v2:
>> - rearranged patches
>> - fixed compilation issues for x86
>>
>> Palmer Dabbelt (1):
>>  drivers: of: kexec ima: Support 32-bit platforms
>>
>> Stefan Berger (3):
>>  tpm: of: Make of-tree specific function commonly available
>>  of: kexec: Refactor IMA buffer related functions to make them reusable
>>  tpm/kexec: Duplicate TPM measurement log in of-tree for kexec
>>
>> drivers/char/tpm/eventlog/of.c |  31 +--
>> drivers/of/kexec.c             | 336 ++++++++++++++++++++++++++++-----
>> include/linux/kexec.h          |   6 +
>> include/linux/of.h             |   9 +-
>> include/linux/tpm.h            |  36 ++++
>> kernel/kexec_file.c            |   6 +
>> 6 files changed, 346 insertions(+), 78 deletions(-)
>>
>>
>> base-commit: b90cb1053190353cc30f0fef0ef1f378ccc063c5
>> -- 
>> 2.35.1
>>
>