Differentiate hardware and vms in roles

nixos/machines/ghatanothoa/configuration.nix

@@ -3,6 +3,7 @@
     ./hardware-configuration.nix
     ../../modules/jitsi.nix
     ../../roles
+    ../../roles/vm.nix
     ./network.nix
   ];
 

nixos/roles/default.nix

@@ -1,16 +1,15 @@
 {
   pkgs,
   lib,
-  modulesPath,
   ...
 }: {
   imports = [
     ./admins.nix
     ./nix_keys.nix
     ./prometheusNodeExporter.nix
-    (modulesPath + "/virtualisation/xen-domU.nix")
     ../modules/impermanence.nix
   ];
+
   nix = {
     extraOptions = ''
       experimental-features = nix-command flakes

nixos/roles/hardware.nix

@@ -0,0 +1,6 @@
+{
+  # Use grub as bootloader.
+  # Systemd-boot does not support our legacy BIOS hardware,
+  # but only runs on UEFI systems.
+  boot.loader.grub.enable = true;
+}

nixos/roles/vm.nix

@@ -0,0 +1,5 @@
+{modulesPath, ...}: {
+  imports = [
+    (modulesPath + "/virtualisation/xen-domU.nix")
+  ];
+}