Understanding how guix selects a bootloader variant

Understanding how guix selects a bootloader variant

[Tobias Alexandra Platen]

I am currently trying to build a virtual machine image for powerpc64le.
So I intend to fix known errors, starting with the bootloader:
configure: error: platform "efi" is not supported for target CPU
"powerpc64le". The right bootloader variant for anything powerpc,
starting from G4 is openfirmware. Here is some part of my config:

(bootloader (bootloader-configuration
                (bootloader grub-bootloader)
                (targets '("/dev/sda"))))

Now I am trying to understand where guix selects BIOS/UEFI for a VM
when using grub-bootloader.

Re: Understanding how guix selects a bootloader variant

[Efraim Flashner]

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On Sun, Nov 03, 2024 at 05:38:11PM +0100, Tobias Alexandra Platen wrote:
> I am currently trying to build a virtual machine image for powerpc64le.
> So I intend to fix known errors, starting with the bootloader:
> configure: error: platform "efi" is not supported for target CPU
> "powerpc64le". The right bootloader variant for anything powerpc,
> starting from G4 is openfirmware. Here is some part of my config:
> 
> (bootloader (bootloader-configuration
>                 (bootloader grub-bootloader)
>                 (targets '("/dev/sda"))))
> 
> Now I am trying to understand where guix selects BIOS/UEFI for a VM
> when using grub-bootloader.

From there I'd search in Guix for the code for bootloader-configuration.

I would also start by looking at grub's configure.ac to see what options
exist:

# Specify the platform (such as firmware).
AC_ARG_WITH([platform],
            AS_HELP_STRING([--with-platform=PLATFORM],
                           [select the host platform [[guessed]]]))

# Guess the platform if not specified.
if test "x$with_platform" = x; then
  case "$target_cpu"-"$target_vendor" in
    i386-apple) platform=efi ;;
    i386-*) platform=pc ;;
    x86_64-apple) platform=efi ;;
    x86_64-*) platform=pc ;;
    powerpc-*) platform=ieee1275 ;;
    powerpc64-*) platform=ieee1275 ;;
    powerpc64le-*) platform=ieee1275 ;;
    sparc64-*) platform=ieee1275 ;;
    mipsel-*) platform=loongson ;;
    mips-*) platform=arc ;;
    ia64-*) platform=efi ;;
    arm-*) platform=uboot ;;
    arm64-*) platform=efi ;;
    loongarch64-*) platform=efi;;
    riscv32-*) platform=efi ;;
    riscv64-*) platform=efi ;;
    *)
      AC_MSG_WARN([unsupported CPU: "$target_cpu" - only building utilities])
      platform=none
      ;;
  esac
else
  platform="$with_platform"
fi

I'm pretty sure grub-efi builds for ppc64le, but it looks like you've
selected grub above.

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Re: Understanding how guix selects a bootloader variant

[Tobias Alexandra Platen]

Thats the one I was looking for
On Sun, 2024-11-03 at 20:23 +0200, Efraim Flashner wrote:
> powerpc-*) platform=ieee1275 ;;
>     powerpc64-*) platform=ieee1275 ;;
>     powerpc64le-*) platform=ieee1275 ;;

Re: Understanding how guix selects a bootloader variant

[Felix Lechner via Development of GNU Guix and the GNU System distribution.]

Hi Tobias Alexandra,

On Sun, Nov 03 2024, Tobias Alexandra Platen wrote:

> where guix selects BIOS/UEFI for a VM when using grub-bootloader.

I believe it happens here [1] but via "bootloader-configuration".

I personally find Guix's bootloader code convoluted.

Kind regards
Felix

P.S. I referred to my clone on Codeberg because I do not know how to
generate Permalinks for Savannah.

[1] https://codeberg.org/lechner/guix/src/commit/5f4ba1c09fa0fba1ed230b80bae9f6a4d0d2d303/gnu/bootloader/grub.scm#L905