diff --git a/pkgs/build-support/vm/default.nix b/pkgs/build-support/vm/default.nix
index 5b407f530dc8..81a9f89dd100 100644
--- a/pkgs/build-support/vm/default.nix
+++ b/pkgs/build-support/vm/default.nix
@@ -261,9 +261,12 @@ rec {
       exit 1
     fi
 
-    eval "$postVM"
+    exitCode="$(cat xchg/in-vm-exit)"
+    if [ "$exitCode" != "0" ]; then
+      exit "$exitCode"
+    fi
 
-    exit $(cat xchg/in-vm-exit)
+    eval "$postVM"
   '';