anchor.diff:      (mkRenamedOptionModule
         [ "virtualisation" "libvirtd" "qemuOvmf" ]
         [ "virtualisation" "libvirtd" "qemu" "ovmf" "enable" ])
  -    (mkRenamedOptionModule
  +    (mkRemovedOptionModule
         [ "virtualisation" "libvirtd" "qemuOvmfPackage" ]
  -      [ "virtualisation" "libvirtd" "qemu" "ovmf" "package" ])
  +      "If this option was set to `foo`, set the option `virtualisation.libvirtd.qemu.ovmf.packages' to `[foo.fd]` instead.")
       (mkRenamedOptionModule
         [ "virtualisation" "libvirtd" "qemuSwtpm" ]
         [ "virtualisation" "libvirtd" "qemu" "swtpm" "enable" ])
  
positive.code: 
      assertions = [
        {
          assertion = config.security.polkit.enable;
          message = "The libvirtd module currently requires Polkit to be enabled ('security.polkit.enable = true').";
        }
        {
          assertion = builtins.elem "fd" cfg.qemu.ovmf.package.outputs;
          message = "The option 'virtualisation.libvirtd.qemuOvmfPackage' needs a package that has an 'fd' output.";
        }
      ];
  
  
negative.code:     auth_unix_rw = "polkit"
      ${cfg.extraConfig}
    '';
    qemuConfigFile = pkgs.writeText "qemu.conf" ''
      ${optionalString cfg.qemu.ovmf.enable ''
        nvram = [ "/run/libvirt/nix-ovmf/AAVMF_CODE.fd:/run/libvirt/nix-ovmf/AAVMF_VARS.fd", "/run/libvirt/nix-ovmf/OVMF_CODE.fd:/run/libvirt/nix-ovmf/OVMF_VARS.fd" ]
      ''}
      ${optionalString (!cfg.qemu.runAsRoot) ''
        user = "qemu-libvirtd"
  