allow configuring whether a node uses QEMU

infra/common/nixos/hardware.nix

@@ -1,64 +1,86 @@
-{ modulesPath, ... }:
+{ config, lib, ... }:
 
+let
+  inherit (lib) mkIf mkMerge;
+
+in
 {
   _class = "nixos";
 
-  imports = [ (modulesPath + "/profiles/qemu-guest.nix") ];
+  config = mkMerge [
+    {
+      boot.loader = {
+        systemd-boot.enable = true;
+        efi.canTouchEfiVariables = true;
+      };
+    }
 
-  boot = {
+    (mkIf config.fediversityVm.isQemuVm {
-    loader = {
-      systemd-boot.enable = true;
-      efi.canTouchEfiVariables = true;
-    };
 
-    initrd = {
+      boot.initrd = {
-      availableKernelModules = [
+        availableKernelModules = [
-        "ata_piix"
+          "ata_piix"
-        "uhci_hcd"
+          "uhci_hcd"
-        "virtio_pci"
+          "sd_mod"
-        "virtio_scsi"
+          "sr_mod"
-        "sd_mod"
-        "sr_mod"
-      ];
-      kernelModules = [ "dm-snapshot" ];
-    };
-  };
 
-  disko.devices.disk.main = {
+          # from `/profiles/qemu-guest.nix`
-    device = "/dev/sda";
+          "virtio_net"
-    type = "disk";
+          "virtio_pci"
+          "virtio_mmio"
+          "virtio_blk"
+          "virtio_scsi"
+          "9p"
+          "9pnet_virtio"
+        ];
+        kernelModules = [
+          "dm-snapshot"
 
-    content = {
+          # from `/profiles/qemu-guest.nix`
-      type = "gpt";
+          "virtio_balloon"
+          "virtio_console"
+          "virtio_rng"
+          "virtio_gpu"
+        ];
+      };
 
-      partitions = {
+      disko.devices.disk.main = {
-        MBR = {
+        device = "/dev/sda";
-          priority = 0;
+        type = "disk";
-          size = "1M";
-          type = "EF02";
-        };
 
-        ESP = {
+        content = {
-          priority = 1;
+          type = "gpt";
-          size = "500M";
-          type = "EF00";
-          content = {
-            type = "filesystem";
-            format = "vfat";
-            mountpoint = "/boot";
-          };
-        };
 
-        root = {
+          partitions = {
-          priority = 2;
+            MBR = {
-          size = "100%";
+              priority = 0;
-          content = {
+              size = "1M";
-            type = "filesystem";
+              type = "EF02";
-            format = "ext4";
+            };
-            mountpoint = "/";
+
+            ESP = {
+              priority = 1;
+              size = "500M";
+              type = "EF00";
+              content = {
+                type = "filesystem";
+                format = "vfat";
+                mountpoint = "/boot";
+              };
+            };
+
+            root = {
+              priority = 2;
+              size = "100%";
+              content = {
+                type = "filesystem";
+                format = "ext4";
+                mountpoint = "/";
+              };
+            };
           };
         };
       };
-    };
+    })
-  };
+  ];
 }

infra/common/options.nix

@@ -155,5 +155,13 @@ in
         this for testing machines, as it is a security hole for so many reasons.
       '';
     };
+
+    isQemuVm = mkOption {
+      description = ''
+        Whether the machine is a QEMU VM. This will import all the necessary
+        things.
+      '';
+      default = true;
+    };
   };
 }