linux-kernel - Re: [PATCH v1 08/14] x86: make CONFIG_EFI

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Message-ID: <CAFLszTi+N7Yj0yYHKroypmBoFSx+9m5er8pgULsKbPuooFYj-A@mail.gmail.com>
Date: Tue, 27 Jan 2026 10:19:37 +1300
From: Simon Glass <sjg@...omium.org>
To: "H. Peter Anvin" <hpa@...or.com>
Cc: ubizjak@...il.com, linux-kernel@...r.kernel.org, akpm@...ux-foundation.org, 
	bp@...en8.de, dave.hansen@...ux.intel.com, kas@...nel.org, kees@...nel.org, 
	linux-coco@...ts.linux.dev, mingo@...hat.com, nathan@...nel.org, 
	peterz@...radead.org, pmladek@...e.com, rick.p.edgecombe@...el.com, 
	tglx@...nel.org, x86@...nel.org
Subject: Re: [PATCH v1 08/14] x86: make CONFIG_EFI_STUB unconditional

Hi Peter,

On Fri, 23 Jan 2026 at 13:11, H. Peter Anvin <hpa@...or.com> wrote:
>
> On January 22, 2026 10:57:39 AM PST, Simon Glass <sjg@...omium.org> wrote:
> >Hi Peter,
> >
> >On Tue, Jan 20, 2026 at 8:54 PM H. Peter Anvin <hpa@...or.com> wrote:
> >>
> >> The EFI stub code is mature, most current x86 systems require EFI to
> >> boot, and as it is exclusively preboot code, it doesn't affect the
> >> runtime memory footprint at all.
> >>
> >> It makes absolutely no sense to omit it anymore, so make it
> >> unconditional.
> >>
> >> Signed-off-by: H. Peter Anvin (Intel) <hpa@...or.com>
> >> ---
> >>  arch/x86/Kconfig                  | 14 ++------------
> >>  arch/x86/boot/compressed/Makefile |  2 --
> >>  arch/x86/boot/compressed/error.c  |  2 --
> >>  arch/x86/boot/header.S            |  3 ---
> >>  4 files changed, 2 insertions(+), 19 deletions(-)
> >
> >At least with QEMU the EFI protocol adds quite a lot of overhead.
> >
> >Is there any actual need for this?
> >
> >Regards,
> >Simon
> >
>
> Including the EFI stub doesn't mean using EFI to boot is required.

Yes, understood, but it adds bloat. More importantly it will lead to
people assuming that the stub is always used and thus unwittingly blur
the boundary between the stub and the kernel itself.

What is the actual need for this?

Regards,
Simon