From 57c9e00000d7530693968262bbc239e1371f5bba Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dav=C3=AD=C3=B0=20Steinn=20Geirsson?= <david@dsg.is>
Date: Sat, 21 Mar 2026 19:47:10 +0000
Subject: [PATCH] refactor: make console-relay service crosvm-only

Cloud-hypervisor VMs now use PTY-direct serial mode and no longer need
a console-relay service. Filter the relay to crosvm VMs only via
lib.filter, removing the isCh/chRelayScript conditional logic. Also
add ExecStopPost cleanup of the console symlink for CH VMs.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 modules/services.nix | 49 ++++++++++++--------------------------------
 1 file changed, 13 insertions(+), 36 deletions(-)

diff --git a/modules/services.nix b/modules/services.nix
index 50ac8fc..9e6f18e 100644
--- a/modules/services.nix
+++ b/modules/services.nix
@@ -403,6 +403,9 @@ in
                   rm -f /run/vmsilo/${vm.name}/crosvm-control.socket
                   rm -f /run/vmsilo/${vm.name}/cloud-hypervisor-control.socket
                   rm -f /run/vmsilo/${vm.name}/vsock.socket
+                  ${lib.optionalString (vm.hypervisor == "cloud-hypervisor") ''
+                    rm -f /run/vmsilo/${vm.name}/console
+                  ''}
                 '';
                 usbCleanup = pkgs.writeShellScript "usb-cleanup-${vm.name}" ''
                   source ${cfg._internal.usbHelperLib}
@@ -444,55 +447,29 @@ in
           }
         ) (lib.attrValues cfg.nixosVms)
       ++
-        # Console relay services (one per VM)
+        # Console relay services (one per crosvm VM)
         # Bridges serial backend to a persistent PTY so users can attach/detach
         map (
           vm:
-          let
-            isCh = vm.hypervisor == "cloud-hypervisor";
-            # crosvm connects to a socket we listen on; cloud-hypervisor creates its own socket we connect to
-            chRelayScript = pkgs.writeShellScript "console-relay-${vm.name}" ''
-              # Wait for cloud-hypervisor to create the serial socket
-              ELAPSED=0
-              while [ ! -S /run/vmsilo/${vm.name}/serial.socket ] && [ $ELAPSED -lt 120 ]; do
-                sleep 0.5
-                ELAPSED=$((ELAPSED + 1))
-              done
-              if [ ! -S /run/vmsilo/${vm.name}/serial.socket ]; then
-                echo "Timeout waiting for serial socket" >&2
-                exit 1
-              fi
-              exec ${pkgs.socat}/bin/socat UNIX-CONNECT:/run/vmsilo/${vm.name}/serial.socket PTY,link=/run/vmsilo/${vm.name}/console,raw,echo=0,user=${toString userUid},mode=0600
-            '';
-          in
           lib.nameValuePair "vmsilo-${vm.name}-console-relay" {
             description = "Console relay for VM ${vm.name}";
-            after = if isCh then [ "vmsilo-${vm.name}-vm.service" ] else [ "vmsilo-${vm.name}-prep.service" ];
-            before = lib.optionals (!isCh) [ "vmsilo-${vm.name}-vm.service" ];
-            requiredBy = lib.optionals (!isCh) [ "vmsilo-${vm.name}-vm.service" ];
-            wantedBy = lib.optionals isCh [ "vmsilo-${vm.name}-vm.service" ];
+            after = [ "vmsilo-${vm.name}-prep.service" ];
+            before = [ "vmsilo-${vm.name}-vm.service" ];
+            requiredBy = [ "vmsilo-${vm.name}-vm.service" ];
             bindsTo = [ "vmsilo-${vm.name}-vm.service" ];
 
             serviceConfig = {
               Type = "simple";
-              ExecStartPre =
-                lib.optionals (!isCh) [
-                  "-${pkgs.coreutils}/bin/rm -f /run/vmsilo/${vm.name}/console-backend.socket"
-                ]
-                ++ [
-                  "-${pkgs.coreutils}/bin/rm -f /run/vmsilo/${vm.name}/console"
-                ];
-              ExecStart =
-                if isCh then
-                  "${chRelayScript}"
-                else
-                  # crosvm: listen for crosvm to connect
-                  "${pkgs.socat}/bin/socat UNIX-LISTEN:/run/vmsilo/${vm.name}/console-backend.socket,fork,reuseaddr PTY,link=/run/vmsilo/${vm.name}/console,raw,echo=0,user=${toString userUid},mode=0600";
+              ExecStartPre = [
+                "-${pkgs.coreutils}/bin/rm -f /run/vmsilo/${vm.name}/console-backend.socket"
+                "-${pkgs.coreutils}/bin/rm -f /run/vmsilo/${vm.name}/console"
+              ];
+              ExecStart = "${pkgs.socat}/bin/socat UNIX-LISTEN:/run/vmsilo/${vm.name}/console-backend.socket,fork,reuseaddr PTY,link=/run/vmsilo/${vm.name}/console,raw,echo=0,user=${toString userUid},mode=0600";
               Restart = "on-failure";
               RestartSec = "1s";
             };
           }
-        ) (lib.attrValues cfg.nixosVms)
+        ) (lib.filter (vm: vm.hypervisor == "crosvm") (lib.attrValues cfg.nixosVms))
       ++
         # virtiofsd services (one per shared directory per VM)
         lib.concatMap (