feat: add per-VM tray.enable option (default false)

Tray proxy was unconditionally enabled for all crosvm VMs. Add
tray.enable so it must be opted into per VM. When disabled, neither
the host-side tray service nor the guest-side tray daemon are created.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

README.md

@@ -171,6 +171,7 @@ There are a lot of configuration options but you don't really need to touch most
 | `color` | string | `"darkred"` | Window decoration color (named color or hex, e.g., `"#2ecc71"`) |
 | `network.nameservers` | list of strings | `[]` | DNS nameservers for this VM |
 | `network.interfaces` | attrset of interface configs | `{}` | Network interfaces (keys are guest-visible names) |
+| `tray.enable` | bool | `false` | Enable tray proxy for this VM (proxies guest SNI tray items to host system tray) |
 | `autoShutdown.enable` | bool | `false` | Auto-shutdown when idle (after `autoShutdown.after` seconds) |
 | `autoShutdown.after` | int | `60` | Seconds to wait before shutdown |
 | `autoStart` | bool | `false` | Start VM automatically (GPU VMs: on session start; non-GPU VMs: at boot) |
@@ -575,7 +576,7 @@ The host provides:
 
 ### Tray Integration
 
-VM system tray applets (StatusNotifierItems like nm-applet, bluetooth, etc.) automatically appear in the host KDE system tray. No configuration needed — tray proxying is always enabled.
+VM system tray applets (StatusNotifierItems like nm-applet, bluetooth, etc.) can appear in the host KDE system tray. Enable per VM with `tray.enable = true`.
 
 - Tray items are prefixed with the VM name (e.g., `[banking] NetworkManager`)
 - User interactions (clicks, scrolls, context menus) are forwarded back to the guest app

modules/options.nix

@@ -251,6 +251,20 @@ let
           '';
         };
 
+        tray = lib.mkOption {
+          type = lib.types.submodule {
+            options = {
+              enable = lib.mkOption {
+                type = lib.types.bool;
+                default = false;
+                description = "Enable host-side tray proxy for this VM. Proxies guest SNI tray items to the host system tray.";
+              };
+            };
+          };
+          default = { };
+          description = "Tray proxy configuration for this VM.";
+        };
+
         autoShutdown = lib.mkOption {
           type = lib.types.submodule {
             options = {

modules/scripts.nix

@@ -498,7 +498,7 @@ let
     pkgs.callPackage ../rootfs-nixos {
       inherit (cfg._internal) wayland-proxy-virtwl sommelier;
       inherit soundConfig;
-      vmsilo-tray = cfg._internal.vmsilo-tray;
+      vmsilo-tray = if vm.tray.enable then cfg._internal.vmsilo-tray else null;
       trayLogLevel = cfg.vmsilo-tray.logLevel;
       waylandProxy = vm.waylandProxy;
       guestPrograms = vm.guestPrograms;

modules/services.nix

@@ -275,53 +275,53 @@ in
         }
       ) (lib.attrValues cfg.nixosVms)
       ++
-      # VM services (run crosvm as root)
-      map (
-        vm:
-        lib.nameValuePair "vmsilo-${vm.name}-vm" {
-          description = "vmsilo VM: ${vm.name}";
-          wantedBy = lib.optionals (vm.autoStart && vm.gpu == false) [ "multi-user.target" ];
-          wants =
-            map (depName: "vmsilo-${depName}-vm.service") vm.dependsOn
-            ++ lib.optional (
-              vm.network.netvm != null && vm.network.netvm != "host"
-            ) "vmsilo-${vm.network.netvm}-vm.service"
-            ++ map (brName: "${brName}-netdev.service") (vmBridges vm);
-          after = [ "network.target" ] ++ map (brName: "${brName}-netdev.service") (vmBridges vm);
-          serviceConfig =
-            let
-              ephemeralPath = "/var/lib/vmsilo/${vm.name}-ephemeral.raw";
-              createEphemeral = pkgs.writeShellScript "create-ephemeral-${vm.name}" ''
-                truncate -s ${vm.rootOverlay.size} ${ephemeralPath}
-              '';
-              deleteEphemeral = pkgs.writeShellScript "delete-ephemeral-${vm.name}" ''
-                rm -f ${ephemeralPath}
-              '';
-              startPreScripts = lib.optionals (vm.rootOverlay.type == "raw") [ "${createEphemeral}" ];
-              cleanupSocket = pkgs.writeShellScript "cleanup-socket-${vm.name}" ''
-                rm -f /run/vmsilo/${vm.name}/crosvm-control.socket
-                rm -f /run/vmsilo/${vm.name}/cloud-hypervisor-control.socket
-              '';
-              usbCleanup = pkgs.writeShellScript "usb-cleanup-${vm.name}" ''
-                source ${cfg._internal.usbHelperLib}
-                usb_cleanup_vm "${vm.name}"
-              '';
-              stopPostScripts = [
-                "${cleanupSocket}"
-              ]
-              ++ lib.optional (vm.hypervisor == "crosvm") "${usbCleanup}"
-              ++ lib.optionals (vm.rootOverlay.type == "raw") [ "${deleteEphemeral}" ];
-            in
-            {
-              Type = "simple";
-              ExecStart = "${cfg._internal.vmScripts.${vm.name}}";
-              ExecStopPost = stopPostScripts;
-            }
-            // lib.optionalAttrs (startPreScripts != [ ]) {
-              ExecStartPre = startPreScripts;
-            };
-        }
-      ) (lib.attrValues cfg.nixosVms)
+        # VM services (run crosvm as root)
+        map (
+          vm:
+          lib.nameValuePair "vmsilo-${vm.name}-vm" {
+            description = "vmsilo VM: ${vm.name}";
+            wantedBy = lib.optionals (vm.autoStart && vm.gpu == false) [ "multi-user.target" ];
+            wants =
+              map (depName: "vmsilo-${depName}-vm.service") vm.dependsOn
+              ++ lib.optional (
+                vm.network.netvm != null && vm.network.netvm != "host"
+              ) "vmsilo-${vm.network.netvm}-vm.service"
+              ++ map (brName: "${brName}-netdev.service") (vmBridges vm);
+            after = [ "network.target" ] ++ map (brName: "${brName}-netdev.service") (vmBridges vm);
+            serviceConfig =
+              let
+                ephemeralPath = "/var/lib/vmsilo/${vm.name}-ephemeral.raw";
+                createEphemeral = pkgs.writeShellScript "create-ephemeral-${vm.name}" ''
+                  truncate -s ${vm.rootOverlay.size} ${ephemeralPath}
+                '';
+                deleteEphemeral = pkgs.writeShellScript "delete-ephemeral-${vm.name}" ''
+                  rm -f ${ephemeralPath}
+                '';
+                startPreScripts = lib.optionals (vm.rootOverlay.type == "raw") [ "${createEphemeral}" ];
+                cleanupSocket = pkgs.writeShellScript "cleanup-socket-${vm.name}" ''
+                  rm -f /run/vmsilo/${vm.name}/crosvm-control.socket
+                  rm -f /run/vmsilo/${vm.name}/cloud-hypervisor-control.socket
+                '';
+                usbCleanup = pkgs.writeShellScript "usb-cleanup-${vm.name}" ''
+                  source ${cfg._internal.usbHelperLib}
+                  usb_cleanup_vm "${vm.name}"
+                '';
+                stopPostScripts = [
+                  "${cleanupSocket}"
+                ]
+                ++ lib.optional (vm.hypervisor == "crosvm") "${usbCleanup}"
+                ++ lib.optionals (vm.rootOverlay.type == "raw") [ "${deleteEphemeral}" ];
+              in
+              {
+                Type = "simple";
+                ExecStart = "${cfg._internal.vmScripts.${vm.name}}";
+                ExecStopPost = stopPostScripts;
+              }
+              // lib.optionalAttrs (startPreScripts != [ ]) {
+                ExecStartPre = startPreScripts;
+              };
+          }
+        ) (lib.attrValues cfg.nixosVms)
       ++
         # Proxy template services (per-connection)
         map (
@@ -478,7 +478,7 @@ in
         # Tray proxy services (crosvm VMs only — kernel vsock required)
         lib.concatMap (
           vm:
-          lib.optional (vm.hypervisor == "crosvm") (
+          lib.optional (vm.tray.enable && vm.hypervisor == "crosvm") (
             lib.nameValuePair "vmsilo-${vm.name}-tray" {
               description = "Tray proxy for VM ${vm.name}";
               wantedBy = [ "vmsilo-${vm.name}-vm.service" ];