linux-kernel - Re: [PATCH 0/2] efi: Expose the runtime-services workqueue via sysfs

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Message-ID: <20260209155528.k7RMRPVD@linutronix.de>
Date: Mon, 9 Feb 2026 16:55:28 +0100
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To: "Luis Claudio R. Goncalves" <lgoncalv@...hat.com>
Cc: linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-rt-devel@...ts.linux.dev, Ard Biesheuvel <ardb@...nel.org>,
	John Ogness <john.ogness@...utronix.de>,
	Lai Jiangshan <jiangshanlai@...il.com>, Tejun Heo <tj@...nel.org>
Subject: Re: [PATCH 0/2] efi: Expose the runtime-services workqueue via sysfs

On 2026-02-09 12:17:35 [-0300], Luis Claudio R. Goncalves wrote:
> Sebastian, as for the TEE feature you mentioned, is there specific test I
> should run? Or is there any test you would like me to run in the context of
> this change?

Puh.
If you have a TEE environment, then the EFI interface should be
"supplied" the TEE instead the runtime-wrappers. My guess is that
tee_get_variable() would be used instead and here the workqueue won't be
used (I think). So that is the easy part.

What I don't know is if this is a problem, i.e. is it possible to
interrupt the secure monitor and continue in Linux before heading back
to the secure environment or not.
If you could check how long you end up in the next variable and RTC call
and if the time is noticeable, do you see it in cyclictest or not.
So if the EFI-TEE-RTC-callback takes always >1ms and you don't see this
in cyclictest as a spike then it should be good.

Sebastian