diff --git a/lib/eval-config.nix b/lib/eval-config.nix
index 4a1853a8d32..9dccc62e1ec 100644
--- a/lib/eval-config.nix
+++ b/lib/eval-config.nix
@@ -6,8 +6,11 @@
 , system ? builtins.currentSystem
 , nixpkgs ? import ./from-env.nix "NIXPKGS" /etc/nixos/nixpkgs
 , pkgs ? import nixpkgs {inherit system;}
+, extraArgs ? {}
 }:
 
+let extraArgs_ = extraArgs; in
+
 rec {
   inherit nixpkgs pkgs;
 
@@ -16,7 +19,7 @@ rec {
     ./check-config.nix
   ] ++ (import ../modules/module-list.nix);
 
-  extraArgs = {
+  extraArgs = extraArgs_ // {
     inherit pkgs;
     modulesPath = ../modules;
   };