Subject: Re: bug#26815: [PATCH 3/3] vm: Support EFI boot in base image.

From: Marius Bakke <[email-masked]>
Date: Sun, 07 May 2017 21:17:49 +0200

Danny Milosavljevic <[email-masked]> writes:

> Hi Marius,
>
>> +      (system* "grub-mkstandalone" "-O" "x86_64-efi" "-o"
>> +               (string-append efi-directory "/EFI/BOOT/BOOTX64.EFI")
>> +               ;; Embed the contents of grubdisk.cfg.
>> +               (string-append "boot/grub/grub.cfg=" target
>> +                              "/tmp/grubdisk.cfg"))
>
> Check return value of system* ?

I rewrote most of this to be (hopefully) more understandable. Also, some
rudimentary steps towards other platforms, native testing required.

V2 attached.

From e94c9071c53db28c3e73998654b185c36a210df6 Mon Sep 17 00:00:00 2001
From: Marius Bakke <[email-masked]>
Date: Sun, 7 May 2017 15:31:30 +0200
Subject: [PATCH] vm: Support EFI boot in base image.

* gnu/system/vm.scm (qemu-image): Add GRUB-EFI to inputs. Append 40MB
EFI System Partition.
* gnu/build/vm.scm (initialize-hard-disk): Generate grub EFI blob when ESP is
present.
---
 gnu/build/vm.scm  | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 gnu/system/vm.scm | 14 ++++++++++---
 2 files changed, 69 insertions(+), 4 deletions(-)

diff --git a/gnu/build/vm.scm b/gnu/build/vm.scm
index 206696ef6..8b4a44579 100644
--- a/gnu/build/vm.scm
+++ b/gnu/build/vm.scm
@@ -27,6 +27,7 @@
   #:use-module (gnu build linux-boot)
   #:use-module (gnu build install)
   #:use-module (guix records)
+  #:use-module (ice-9 format)
   #:use-module (ice-9 match)
   #:use-module (ice-9 regex)
   #:use-module (srfi srfi-1)
@@ -334,9 +335,16 @@ passing it a directory name where it is mounted."
     "Return the first partition found with the boot flag set."
     (member 'boot (partition-flags partitions)))
 
+  (define (partition-esp? partitions)
+    "Return the first EFI System Partition."
+    (member 'esp (partition-flags partitions)))
+
   (let* ((partitions (initialize-partition-table device partitions))
          (root       (find partition-bootable? partitions))
-         (target     "/fs"))
+         (esp        (find partition-esp? partitions))
+         (target     "/fs")
+         ;; Grub expects to find an EFI System Partition here.
+         (efi-directory (string-append target "/boot/efi")))
     (unless root
       (error "no bootable partition specified" partitions))
 
@@ -346,6 +354,55 @@ passing it a directory name where it is mounted."
     (mkdir-p target)
     (mount (partition-device root) target (partition-file-system root))
     (install-boot-config bootcfg bootcfg-location target)
+
+    ;; If we have an ESP partition, generate a self-contained grub EFI
+    ;; image and write it to a well-known location.
+    (when esp
+      (let* ((system %host-type)
+             (efi-payload-directory (string-append efi-directory "/EFI/BOOT"))
+             (efi-payload-file-name (if (any (cute string-prefix? <> system)
+                                             '("i686" "armhf"))
+                                        "BOOTX32.EFI"       ;hail mary
+                                        "BOOTX64.EFI"))     ;fairly supported
+             (efi-payload-format (cond
+                                  ((string-prefix? "x86_64" system)
+                                   "x86_64-efi")
+                                  ((string-prefix? "i686" system)
+                                   "i386-efi")
+                                  ((string-prefix? "armhf" system)
+                                   "arm-efi")
+                                  ((string-prefix? "aarch64" system)
+                                   "arm64-efi")))
+             (grub-tmp (string-append target "/tmp"))
+             (grub.cfg (string-append grub-tmp "/grub.cfg")))
+        (display "mounting EFI system partition...\n")
+        (mkdir-p efi-directory)
+        (mount (partition-device esp) efi-directory
+               (partition-file-system esp))
+        (mkdir-p efi-payload-directory)
+
+        ;; Grub needs a tmpdir to prepare the image.
+        (setenv "TMPDIR" grub-tmp)
+        ;; We also need a tiny configuration file telling the EFI blob where
+        ;; to find the real thing.
+        (with-output-to-file grub.cfg
+          (lambda _
+            (format #t
+                    "insmod part_msdos~@
+                    search --set=root --label gnu-disk-image~@
+                    configfile /boot/grub/grub.cfg~%")))
+        (display "creating grub firmware image...\n")
+        (unless (zero? (system* "grub-mkstandalone" "-O" efi-payload-format
+                                "-o" (string-append efi-payload-directory "/"
+                                                    efi-payload-file-name)
+                                ;; Graft the contents of our configuration file
+                                ;; into the image.  See grub-mkstandalone(1).
+                                (string-append "boot/grub/grub.cfg=" grub.cfg)))
+          (error "failed to create grub EFI image"))
+
+        (delete-file grub.cfg)
+        (umount efi-directory)))
+
     (when bootloader-installer
       (bootloader-installer bootloader device target))
 
diff --git a/gnu/system/vm.scm b/gnu/system/vm.scm
index 099e3fac3..04ccc3650 100644
--- a/gnu/system/vm.scm
+++ 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.
 ;;;
@@ -202,7 +203,7 @@ 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) '())))
@@ -227,11 +228,18 @@ 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))
+                                    (partition
+                                     ;; Append a small FAT32 partition for
+                                     ;; use with UEFI bootloaders.
+                                     (size (* 40 (expt 2 20)))
+                                     (label "gnu-esp")
+                                     (file-system "vfat")
+                                     (flags '(esp))))))
              (initialize-hard-disk "/dev/vda"
                                    #:partitions partitions
                                    #:bootloader
-- 
2.12.2