Re: [PATCH] efi: add dynamic control interface for EFI runtime services

[Ard Biesheuvel]

On Sat, 15 Aug 2026, at 11:50, Junxiao Chang wrote:
> Add an interface for PREEMPT_RT kernels to dynamically enable or
> disable EFI runtime services.
>
> EFI runtime services are typically disabled on RT systems using
> kernel parameters such as "noefi" or "efi=disable" to avoid
> long latency caused by firmware calls. However, this permanently
> disables EFI runtime services, preventing operations such as UEFI
> firmware updates.
>
> With this change, EFI runtime services can be disabled while
> real-time workloads are running and re-enabled afterwards,
> providing low-latency operation without permanently sacrificing
> firmware functionality.
>
> Signed-off-by: Junxiao Chang <junxiao.chang@xxxxxxxxx>
> ---
>  drivers/firmware/efi/efi.c              | 31 +++++++++++++++++++++++++
>  drivers/firmware/efi/runtime-wrappers.c | 28 ++++++++++++++++++++++
>  include/linux/efi.h                     |  1 +
>  3 files changed, 60 insertions(+)
>

I've queued this up now - thanks.