Subject: Re: bug#26815: [PATCH v4 3/3] vm: Add UEFI loader to disk images.

From: [email-masked] (Ludovic Courtès)
Date: Wed, 17 May 2017 23:28:26 +0200

Marius Bakke <[email-masked]> skribis:

> * gnu/system/vm.scm (qemu-image): Add GRUB-EFI to inputs. Append 40MiB EFI
> System Partition.
> * gnu/build/vm.scm (install-efi): New procedure.
> (initialize-hard-disk): Generate grub EFI blob when ESP is present.

[...]

> +(define (install-efi esp config-file)
> +  "Write a self-contained GRUB EFI loader to the mounted ESP using CONFIG-FILE."
> +  (let* ((system %host-type)
> +         ;; Hard code the output location to a well-known path recognized by
> +         ;; compliant firmware. See "3.5.1.1 Removable Media Boot Behaviour":
> +         ;; http://www.uefi.org/sites/default/files/resources/UEFI%20Spec%202_6.pdf
> +         (efi-directory (string-append esp "/EFI/BOOT"))
> +         ;; Map grub target names to boot file names.
> +         (efi-targets (cond ((string-prefix? "x86_64" system)
> +                             '("x86_64-efi" . "BOOTX64.EFI"))
> +                            ((string-prefix? "i686" system)
> +                             '("i386-efi" . "BOOTIA32.EFI"))
> +                            ((string-prefix? "armhf" system)
> +                             '("arm-efi" . "BOOTARM.EFI"))
> +                            ((string-prefix? "aarch64" system)
> +                             '("arm64-efi" . "BOOTAA64.EFI")))))
> +    ;; GRUB requires a TMPDIR to prepare the firmware image.
> +    (setenv "TMPDIR" esp)
> +
> +    (mkdir-p efi-directory)
> +    (unless (zero? (system* "grub-mkstandalone" "-O" (car efi-targets)
> +                            "-o" (string-append efi-directory "/"
> +                                                (cdr efi-targets))
> +                            ;; Graft the configuration file onto the image.
> +                            (string-append "boot/grub/grub.cfg=" config-file)))

So this is where we need to make sure we’re taking ‘grub-mkstandalone’
from ‘grub-efi’ and not ‘grub’, right?  How do we ensure that?

> +++ b/gnu/system/vm.scm
> @@ -3,6 +3,7 @@
>  ;;; Copyright © 2016 Christopher Allan Webber <[email-masked]>
>  ;;; Copyright © 2016 Leo Famulari <[email-masked]>
>  ;;; Copyright © 2017 Mathieu Othacehe <[email-masked]>
> +;;; Copyright © 2017 Marius Bakke <[email-masked]>
>  ;;;
>  ;;; This file is part of GNU Guix.
>  ;;;
> @@ -203,7 +204,7 @@ the image."
>                        (guix build utils))
>  
>           (let ((inputs
> -                '#$(append (list qemu parted e2fsprogs dosfstools)
> +                '#$(append (list qemu parted e2fsprogs dosfstools grub-efi)
>                             (map canonical-package
>                                  (list sed grep coreutils findutils gawk))
>                             (if register-closures? (list guix) '())))
> @@ -228,11 +229,23 @@ the image."
>                                 #:system-directory #$os-drv))
>                    (partitions (list (partition
>                                       (size #$(- disk-image-size
> -                                                (* 10 (expt 2 20))))
> +                                                (* 50 (expt 2 20))))
>                                       (label #$file-system-label)
>                                       (file-system #$file-system-type)
>                                       (flags '(boot))
> -                                     (initializer initialize)))))
> +                                     (initializer initialize))
> +                                    ;; Append a small EFI System Partition for
> +                                    ;; use with UEFI bootloaders.
> +                                    (partition
> +                                     ;; The standalone grub image is about 10MiB, but
> +                                     ;; leave some room for custom or multiple images.
> +                                     (size (* 40 (expt 2 20)))
> +                                     (label "GNU-ESP")             ;cosmetic only
> +                                     ;; Use "vfat" here since this property is used
> +                                     ;; when mounting. The actual FAT-ness is based
> +                                     ;; on filesystem size (16 in this case).
> +                                     (file-system "vfat")
> +                                     (flags '(esp))))))
>               (initialize-hard-disk "/dev/vda"
>                                     #:partitions partitions
>                                     #:bootloader-package

I thought we’d pass something like

  (initialize-hard-disk … #:grub-efi #$grub-eif)

to avoid the ambiguity?

Once we’re done with that, we’ll have to update one of the
‘operating-system’ declaration examples to show UEFI configuration, and
to update the doc to explain the installation process for UEFI.

Anyway, thanks for the updated patch series, looks like we’re almost
there!  :-)

Ludo’.