allow configuring whether a node uses QEMU

Reviewed-on: Fediversity/Fediversity#413
Reviewed-by: Valentin Gagarin <valentin.gagarin@tweag.io>
Co-authored-by: Kiara Grouwstra <kiara@procolix.eu>
Co-committed-by: Kiara Grouwstra <kiara@procolix.eu>

infra/common/nixos/hardware.nix

@@ -1,27 +1,47 @@
-{ modulesPath, ... }:
+{ config, lib, ... }:
 
+let
+  inherit (lib) mkIf mkMerge;
+
+in
 {
   _class = "nixos";
 
-  imports = [ (modulesPath + "/profiles/qemu-guest.nix") ];
+  config = mkMerge [
-
+    {
-  boot = {
+      boot.loader = {
-    loader = {
         systemd-boot.enable = true;
         efi.canTouchEfiVariables = true;
       };
+    }
 
-    initrd = {
+    (mkIf config.fediversityVm.isQemuVm {
+
+      boot.initrd = {
         availableKernelModules = [
           "ata_piix"
           "uhci_hcd"
-        "virtio_pci"
-        "virtio_scsi"
           "sd_mod"
           "sr_mod"
+
+          # from `/profiles/qemu-guest.nix`
+          "virtio_net"
+          "virtio_pci"
+          "virtio_mmio"
+          "virtio_blk"
+          "virtio_scsi"
+          "9p"
+          "9pnet_virtio"
+        ];
+        kernelModules = [
+          "dm-snapshot"
+
+          # from `/profiles/qemu-guest.nix`
+          "virtio_balloon"
+          "virtio_console"
+          "virtio_rng"
+          "virtio_gpu"
         ];
-      kernelModules = [ "dm-snapshot" ];
-    };
       };
 
       disko.devices.disk.main = {
@@ -61,4 +81,6 @@
           };
         };
       };
+    })
+  ];
 }

infra/common/nixos/networking.nix

@@ -1,7 +1,7 @@
 { config, lib, ... }:
 
 let
-  inherit (lib) mkDefault;
+  inherit (lib) mkDefault mkIf mkMerge;
 
 in
 {
@@ -13,41 +13,14 @@ in
       settings.PasswordAuthentication = false;
     };
 
-    networking = {
+    networking = mkMerge [
+      {
         hostName = config.fediversityVm.name;
         domain = config.fediversityVm.domain;
 
         ## REVIEW: Do we actually need that, considering that we have static IPs?
         useDHCP = mkDefault true;
 
-      interfaces = {
-        eth0 = {
-          ipv4 = {
-            addresses = [
-              {
-                inherit (config.fediversityVm.ipv4) address prefixLength;
-              }
-            ];
-          };
-          ipv6 = {
-            addresses = [
-              {
-                inherit (config.fediversityVm.ipv6) address prefixLength;
-              }
-            ];
-          };
-        };
-      };
-
-      defaultGateway = {
-        address = config.fediversityVm.ipv4.gateway;
-        interface = "eth0";
-      };
-      defaultGateway6 = {
-        address = config.fediversityVm.ipv6.gateway;
-        interface = "eth0";
-      };
-
         nameservers = [
           "95.215.185.6"
           "95.215.185.7"
@@ -60,6 +33,29 @@ in
           enable = true;
           rulesetFile = ./nftables-ruleset.nft;
         };
+      }
+
+      ## IPv4
+      (mkIf config.fediversityVm.ipv4.enable {
+        interfaces.${config.fediversityVm.ipv4.interface}.ipv4.addresses = [
+          { inherit (config.fediversityVm.ipv4) address prefixLength; }
+        ];
+        defaultGateway = {
+          address = config.fediversityVm.ipv4.gateway;
+          interface = config.fediversityVm.ipv4.interface;
         };
+      })
+
+      ## IPv6
+      (mkIf config.fediversityVm.ipv6.enable {
+        interfaces.${config.fediversityVm.ipv6.interface}.ipv6.addresses = [
+          { inherit (config.fediversityVm.ipv6) address prefixLength; }
+        ];
+        defaultGateway6 = {
+          address = config.fediversityVm.ipv6.gateway;
+          interface = config.fediversityVm.ipv6.interface;
+        };
+      })
+    ];
   };
 }

infra/common/options.nix

@@ -91,6 +91,17 @@ in
     };
 
     ipv4 = {
+      enable = mkOption {
+        default = true;
+      };
+
+      interface = mkOption {
+        description = ''
+          The interface that carries the machine's IPv4 network.
+        '';
+        default = "eth0";
+      };
+
       address = mkOption {
         description = ''
           The IP address of the machine, version 4. It will be injected as a
@@ -116,6 +127,17 @@ in
     };
 
     ipv6 = {
+      enable = mkOption {
+        default = true;
+      };
+
+      interface = mkOption {
+        description = ''
+          The interface that carries the machine's IPv6 network.
+        '';
+        default = "eth0";
+      };
+
       address = mkOption {
         description = ''
           The IP address of the machine, version 6. It will be injected as a
@@ -155,5 +177,13 @@ 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;
+    };
   };
 }