linux-kernel - Re: [PATCH v8 0/5] introduce tee-based EFI Runtime Variable Service

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Date:   Wed, 16 Aug 2023 16:07:46 +0200
From:   Jan Kiszka <jan.kiszka@...mens.com>
To:     Ilias Apalodimas <ilias.apalodimas@...aro.org>,
        Masahisa Kojima <masahisa.kojima@...aro.org>
Cc:     Ard Biesheuvel <ardb@...nel.org>,
        Heinrich Schuchardt <heinrich.schuchardt@...onical.com>,
        Jens Wiklander <jens.wiklander@...aro.org>,
        Johan Hovold <johan+linaro@...nel.org>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Randy Dunlap <rdunlap@...radead.org>,
        Sumit Garg <sumit.garg@...aro.org>,
        linux-kernel@...r.kernel.org, op-tee@...ts.trustedfirmware.org
Subject: Re: [PATCH v8 0/5] introduce tee-based EFI Runtime Variable Service

On 16.08.23 13:58, Ilias Apalodimas wrote:
> On Tue, 15 Aug 2023 at 05:41, Masahisa Kojima
> <masahisa.kojima@...aro.org> wrote:
>>
>> Hi Jan,
>>
>> 2023年8月15日(火) 2:23 Jan Kiszka <jan.kiszka@...mens.com>:
>>>
>>> On 14.08.23 11:24, Ilias Apalodimas wrote:
>>>> Hi Jan,
>>>>
>>>> On Mon, 7 Aug 2023 at 05:53, Masahisa Kojima <masahisa.kojima@...aro.org> wrote:
>>>>>
>>>>> This series introduces the tee based EFI Runtime Variable Service.
>>>>>
>>>>> The eMMC device is typically owned by the non-secure world(linux in
>>>>> this case). There is an existing solution utilizing eMMC RPMB partition
>>>>> for EFI Variables, it is implemented by interacting with
>>>>> OP-TEE, StandaloneMM(as EFI Variable Service Pseudo TA), eMMC driver
>>>>> and tee-supplicant. The last piece is the tee-based variable access
>>>>> driver to interact with OP-TEE and StandaloneMM.
>>>>>
>>>>> Changelog:
>>>>> v7 -> v8
>>>>> Only patch #3 "efi: Add tee-based EFI variable driver" is updated.
>>>>> - fix typos
>>>>> - refactor error handling, direct return if applicable
>>>>> - use devm_add_action_or_reset() for closing of tee context/session
>>>>> - remove obvious comment
>>>>
>>>> Any chance you can run this and see if it solves your issues?
>>>>
>>>
>>> I also need [1], and I still need a cleanup script before terminating
>>> the tee-supplicant, right?
>>
>>
>> Yes, we need patch[1] and a cleanup script.
>> Sorry, I should note in the cover letter.
>>
>>> And if need some service in the initrd
>>> already, I still need to start the supplicant there and transfer its
>>> ownership to systemd later on?
>>
>> Yes.
>>
>>> These patches here only make life easier
>>> if the supplicant is started by systemd, after efivarfs has been
>>> mounted, correct?
> 
> Not systemd specifically.  Any tool that can signal
> <dev>/driver/unbind would work.  Sumit is just reusing the default
> unbind notification mechanism
> 

I was referring to the boot ordering topic, not the shutdown issue.

The latter has now a nicer way to trigger the device shutdown prior to
killing tee-supplicant, but you still need to do that explicitly, no?

Jan

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