diff --git a/modules/testing/test-instrumentation.nix b/modules/testing/test-instrumentation.nix
index b18e4263c2db..6a7f559c3795 100644
--- a/modules/testing/test-instrumentation.nix
+++ b/modules/testing/test-instrumentation.nix
@@ -94,6 +94,10 @@ in
 
     system.upstartEnvironment.GCOV_PREFIX = "/tmp/xchg/coverage-data";
 
+    system.requiredKernelConfig = with config.lib.kernelConfig; [
+      (isYes "SERIAL_8250_CONSOLE")
+      (isYes "SERIAL_8250")
+    ];
   };
 
 }
diff --git a/modules/virtualisation/qemu-vm.nix b/modules/virtualisation/qemu-vm.nix
index dd8b457d43c7..0e9804751bec 100644
--- a/modules/virtualisation/qemu-vm.nix
+++ b/modules/virtualisation/qemu-vm.nix
@@ -385,4 +385,9 @@ in
 
   # Wireless won't work in the VM.
   networking.wireless.enable = mkOverride 50 false;
+
+  system.requiredKernelConfig = optional (!cfg.graphics) (with config.lib.kernelConfig; [
+    (isYes "SERIAL_8250_CONSOLE")
+    (isYes "SERIAL_8250")
+  ]);
 }