nixosTests.limine.bios: init

This patch adds a NixOS test for Limine on BIOS systems. It also fixes
some formatting in `nixos/lib/make-disk-image.nix`.

Signed-off-by: John Titor <50095635+JohnRTitor@users.noreply.github.com>

nixos/lib/make-disk-image.nix

@@ -742,6 +742,15 @@ let
               ''
             ) config.boot.loader.grub.devices
           )}
+          ${
+            let
+              limine = config.boot.loader.limine;
+            in
+            lib.optionalString (limine.enable && limine.biosSupport && limine.biosDevice != "/dev/vda") ''
+              mkdir -p "$(dirname ${limine.biosDevice})"
+              ln -s /dev/vda ${limine.biosDevice}
+            ''
+          }
 
           # Set up core system link, bootloader (sd-boot, GRUB, uboot, etc.), etc.
 

nixos/modules/virtualisation/qemu-vm.nix

@@ -1159,6 +1159,9 @@ in
       `useBootLoader` useless. You might want to disable one of those options.
     '';
 
+    # Install Limine on the bootloader device
+    boot.loader.limine.biosDevice = cfg.bootLoaderDevice;
+
     # In UEFI boot, we use a EFI-only partition table layout, thus GRUB will fail when trying to install
     # legacy and UEFI. In order to avoid this, we have to put "nodev" to force UEFI-only installs.
     # Otherwise, we set the proper bootloader device for this.

nixos/tests/limine/bios.nix

@@ -0,0 +1,28 @@
+{ lib, ... }:
+{
+  name = "bios";
+  meta.maintainers = with lib.maintainers; [
+    lzcunt
+    phip1611
+    programmerlexi
+  ];
+  meta.platforms = [
+    "i686-linux"
+    "x86_64-linux"
+  ];
+  nodes.machine =
+    { ... }:
+    {
+      virtualisation.useBootLoader = true;
+      virtualisation.useBootPartition = true;
+      boot.loader.limine.enable = true;
+      boot.loader.limine.efiSupport = false;
+      boot.loader.timeout = 0;
+    };
+
+  testScript = ''
+    machine.start()
+    with subtest('Machine boots correctly'):
+      machine.wait_for_unit('multi-user.target')
+  '';
+}

nixos/tests/limine/default.nix

@@ -3,6 +3,7 @@
   ...
 }:
 {
+  bios = runTest ./bios.nix;
   checksum = runTest ./checksum.nix;
   secureBoot = runTest ./secure-boot.nix;
   specialisations = runTest ./specialisations.nix;