linux-kernel - Re: [PATCH 0/2] UEFI panic notification mechanism

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Message-ID: <CAMj1kXFDqhvE3R4ckD32ftkb66CjHZcGPCF0OsX6bev2MmnorA@mail.gmail.com>
Date:   Tue, 28 Jun 2022 09:49:56 +0200
From:   Ard Biesheuvel <ardb@...nel.org>
To:     "Guilherme G. Piccoli" <gpiccoli@...lia.com>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        kernel-dev@...lia.com, kernel@...ccoli.net,
        Anton Vorontsov <anton@...msg.org>,
        Colin Cross <ccross@...roid.com>,
        Kees Cook <keescook@...omium.org>,
        Matt Fleming <matt@...eblueprint.co.uk>,
        Matthew Garrett <matthew.garrett@...ula.com>,
        Tony Luck <tony.luck@...el.com>,
        linux-efi <linux-efi@...r.kernel.org>
Subject: Re: [PATCH 0/2] UEFI panic notification mechanism

On Thu, 2 Jun 2022 at 19:40, Guilherme G. Piccoli <gpiccoli@...lia.com> wrote:
>
> Hi Ard, apologies for annoying!
>

No worries, just very busy :-)

> Just a friendly ping asking if you have any opinions about these patches.
>

Honestly, I'm not sure I see the value of this. You want to 'notify
the UEFI firmware' but the firmware doesn't really care about these
variables, only your bespoke tooling does. EFI pstore captures far
more data, so if you just wipe /sys/fs/pstore after each clean boot,
you already have all the data you need, no?

Also, I'm in the process of removing the public efivar_entry_xxx() API
- please look at the efi/next tree for a peek. This is related to your
point 3), i.e., the efivar layer is a disaster in terms of consistency
between different observers of the EFI variable store. Switching to
efivar_set_variable() [the new API] should fix that.