nix/base/base_packages.nix

@@ -76,7 +76,4 @@
   };
   programs.ssh.startAgent = true;
 
-  virtualisation.virtualbox.host.enable = true;
-  users.extraGroups.vboxusers.members = [ "dashie" ];
-  virtualisation.virtualbox.guest.enable = true;
 }

nix/hardware/marmo/configuration.nix

@@ -1,9 +1,14 @@
 { pkgs, ... }:
 {
+  imports = [
+    ../../modules/gamemode.nix
+  ];
   boot.kernelPackages = pkgs.linuxPackages_zen;
   boot.kernelParams = [
     "amdgpu.ppfeaturemask=0xffffffff"
   ];
   networking.hostName = "marmo";
-
+  programs.gamemode = {
+    device = 1;
+  };
 }

nix/hardware/spaceship/configuration.nix

@@ -6,7 +6,14 @@
   ];
   networking.hostName = "spaceship";
 
+  programs.gamemode = {
+    device = 0;
+  };
   environment.systemPackages = with pkgs; [
     linuxKernel.packages.linux_zen.virtualbox
   ];
+
+  virtualisation.virtualbox.host.enable = true;
+  users.extraGroups.vboxusers.members = [ "dashie" ];
+  virtualisation.virtualbox.guest.enable = true;
 }

nix/modules/gamemode.nix

@@ -0,0 +1,11 @@
+{ lib, ... }: {
+  options.programs.gamemode = {
+    device = lib.mkOption {
+      default = 0;
+      example = 0;
+      description = ''
+        GPU device number
+      '';
+    };
+  };
+}

nix/programs/gaming/default.nix

@@ -1,4 +1,5 @@
 { pkgs
+, config
 , ...
 }: {
   imports = [
@@ -24,7 +25,7 @@
       };
       gpu = {
         apply_gpu_optimisations = "accept-responsibility";
-        gpu_device = 0;
+        gpu_device = config.programs.gamemode.device;
         amd_performance_level = "high";
       };
       custom = {