anchor.diff:    # to run 32-bit guests.
     useKvmNestedVirt ? false,
     # Whether to run 64-bit guests instead of 32-bit. Requires nested KVM.
  -  use64bitGuest ? false,
  -  # Whether to enable the virtual UART in VirtualBox guests, allowing to see
  -  # the guest console. There is currently a bug in VirtualBox where this will
  -  # cause a crash if running with SW virtualization
  -  # (https://www.virtualbox.org/ticket/18632). If you need to debug the tests
  -  # then enable this and nested KVM to work around the crash (see above).
  -  enableVBoxUART ? false
  +  use64bitGuest ? false
   }:
   
   assert use64bitGuest -> useKvmNestedVirt;
  -assert enableVBoxUART -> useKvmNestedVirt; # VirtualBox bug, see above
   
   with import ../lib/testing.nix { inherit system pkgs; };
   with pkgs.lib;
  
positive.code:     ];
    in {
      machine = {
        systemd.sockets."vboxtestlog-${name}" = mkIf enableVBoxUART {
          description = "VirtualBox Test Machine Log Socket For ${name}";
          wantedBy = [ "sockets.target" ];
          before = [ "multi-user.target" ];
  
negative.code:         socketConfig.Accept = true;
        };
  
        systemd.services."vboxtestlog-${name}@" = {
          description = "VirtualBox Test Machine Log For ${name}";
          serviceConfig.StandardInput = "socket";
          serviceConfig.StandardOutput = "syslog";
  