[PATCH 1/1] efi_loader: create memory reservations in ACPI case

[Simon Glass]

Hi Heinrich,

On Thu, 16 Nov 2023 at 02:29, Heinrich Schuchardt
<heinrich.schuchardt at canonical.com> wrote:
>
> ACPI tables cannot convey memory reservations for least ARM and RISC-V.
> x86 uses the BIOS E820 table for this purpose. We cannot simply ignore the
> device-tree when booting via ACPI.

Why is that? I had thought that we had to use one or the other. Isn't
the devicetree irrelevant when booting with ACPI, so we can just drop
it?

> We have to assign EfiReservedMemory
> according to the prior stage device-tree ($fdtaddr) or as fallback the
> control device-tree ($fdtcontroladdr).
>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> ---
>  cmd/bootefi.c           | 25 ++++++++++---------------
>  lib/efi_loader/Makefile |  2 --
>  2 files changed, 10 insertions(+), 17 deletions(-)
>

The code looks fine, but I would like to better understand why this is needed.

Regards,
Simon