[microvm] differentiate between stable and unstable nixpkgs

machines/modules/malobeo/microvm_host.nix

@@ -14,6 +14,12 @@ in
         description = lib.mdDoc "Setup bridge device for microvms.";
       };
 
+      enableHostBridgeUnstable = mkOption {
+        default = false;
+        type = types.bool;
+        description = lib.mdDoc "Setup bridge device for microvms.";
+      };
+
       deployHosts = mkOption {
         default = [];
         type = types.listOf types.str;
@@ -29,8 +35,17 @@ in
     inputs.microvm.nixosModules.host
   ];
 
-  config = mkIf cfg.enableHostBridge { 
-    systemd.network = {
+  config = { 
+    assertions = [
+      {
+        assertion = !(cfg.enableHostBridgeUnstable && cfg.enableHostBridge);
+        message = ''
+          Only enableHostBridge or enableHostBridgeUnstable! Not Both!
+        '';
+      }
+    ];
+
+    systemd.network = mkIf (cfg.enableHostBridge || cfg.enableHostBridgeUnstable) {
       enable = true;
       # create a bride device that all the microvms will be connected to
       netdevs."10-microvm".netdevConfig = {
@@ -44,14 +59,11 @@ in
           DHCPServer = true;
           IPv6SendRA = true;
         };
-        addresses = [ {
-          Address = "10.0.0.1/24";
-        } {
-          Address = "fd12:3456:789a::1/64";
-        } ];
-        ipv6Prefixes = [ {
-          Prefix = "fd12:3456:789a::/64";
-        } ];
+        addresses = if cfg.enableHostBridgeUnstable then [
+          { Address = "10.0.0.1/24"; }
+        ] else [
+          { addressConfig.Address = "10.0.0.1/24"; }
+        ];
       };
 
       # connect the vms to the bridge