From b8b86834b74b0b350be3ff3b2d1cdf5146db9dfa Mon Sep 17 00:00:00 2001
From: Maximilian Bosch <maximilian@mbosch.me>
Date: Sat, 10 May 2025 10:38:38 +0200
Subject: [PATCH] nixos/test-driver: move sshBackdoor cfg from
 test-instrumentation to driver

That way, we don't need to duplicate the sshBackdoor options on NixOS-level.

Suggested-by: Jacek Galowicz <jacek@galowicz.de>
---
 nixos/lib/testing/nodes.nix                   | 32 ++++++++++++---
 .../modules/testing/test-instrumentation.nix  | 39 -------------------
 2 files changed, 26 insertions(+), 45 deletions(-)

diff --git a/nixos/lib/testing/nodes.nix b/nixos/lib/testing/nodes.nix
index 2afafe52952e..b2352c478110 100644
--- a/nixos/lib/testing/nodes.nix
+++ b/nixos/lib/testing/nodes.nix
@@ -88,7 +88,7 @@ in
         default = 2;
         type = types.ints.between 2 4294967296;
         description = ''
-          This field is only relevant when multiple users run the (interactive) 
+          This field is only relevant when multiple users run the (interactive)
           driver outside the sandbox and with the SSH backdoor activated.
           The typical symptom for this being a problem are error messages like this:
           `vhost-vsock: unable to set guest cid: Address already in use`
@@ -206,11 +206,31 @@ in
         nixpkgs.pkgs = config.node.pkgs;
         imports = [ ../../modules/misc/nixpkgs/read-only.nix ];
       })
-      (mkIf config.sshBackdoor.enable {
-        testing.sshBackdoor = {
-          inherit (config.sshBackdoor) enable vsockOffset;
-        };
-      })
+      (mkIf config.sshBackdoor.enable (
+        let
+          inherit (config.sshBackdoor) vsockOffset;
+        in
+        { config, ... }:
+        {
+          services.openssh = {
+            enable = true;
+            settings = {
+              PermitRootLogin = "yes";
+              PermitEmptyPasswords = "yes";
+            };
+          };
+
+          security.pam.services.sshd = {
+            allowNullPassword = true;
+          };
+
+          virtualisation.qemu.options = [
+            "-device vhost-vsock-pci,guest-cid=${
+              toString (config.virtualisation.test.nodeNumber + vsockOffset)
+            }"
+          ];
+        }
+      ))
     ];
 
   };
diff --git a/nixos/modules/testing/test-instrumentation.nix b/nixos/modules/testing/test-instrumentation.nix
index 72098f76ddc5..80852be51f1d 100644
--- a/nixos/modules/testing/test-instrumentation.nix
+++ b/nixos/modules/testing/test-instrumentation.nix
@@ -86,27 +86,6 @@ in
       enables commands to be sent to test and debug stage 1. Use
       machine.switch_root() to leave stage 1 and proceed to stage 2
     '';
-
-    sshBackdoor = {
-      enable = mkEnableOption "vsock-based ssh backdoor for the VM";
-      vsockOffset = mkOption {
-        default = 2;
-        type = types.ints.between 2 4294967296;
-        description = ''
-          This field is only relevant when multiple users run the (interactive)
-          driver outside the sandbox and with the SSH backdoor activated.
-          The typical symptom for this being a problem are error messages like this:
-          `vhost-vsock: unable to set guest cid: Address already in use`
-
-          This option allows to assign an offset to each vsock number to
-          resolve this.
-
-          This is a 32bit number. The lowest possible vsock number is `3`
-          (i.e. with the lowest node number being `1`, this is 2+1).
-        '';
-      };
-    };
-
   };
 
   config = {
@@ -120,18 +99,6 @@ in
       }
     ];
 
-    services.openssh = mkIf config.testing.sshBackdoor.enable {
-      enable = true;
-      settings = {
-        PermitRootLogin = "yes";
-        PermitEmptyPasswords = "yes";
-      };
-    };
-
-    security.pam.services.sshd = mkIf config.testing.sshBackdoor.enable {
-      allowNullPassword = true;
-    };
-
     systemd.services.backdoor = lib.mkMerge [
       backdoorService
       {
@@ -207,12 +174,6 @@ in
         #       we avoid defining attributes if not possible.
         # TODO: refactor such that test-instrumentation can import qemu-vm
         package = lib.mkDefault pkgs.qemu_test;
-
-        options = mkIf config.testing.sshBackdoor.enable [
-          "-device vhost-vsock-pci,guest-cid=${
-            toString (config.virtualisation.test.nodeNumber + config.testing.sshBackdoor.vsockOffset)
-          }"
-        ];
       };
     };