anchor.diff:            '';
           };
   
  +      drives =
  +        mkOption {
  +          type = types.listOf (types.submodule driveOpts);
  +          description = "Drives passed to qemu.";
  +        };
  +
         diskInterface =
           mkOption {
             default = "virtio";
  
positive.code: 
      # FIXME: Consolidate this one day.
      virtualisation.qemu.options = mkMerge [
        (mkIf (pkgs.stdenv.isi686 || pkgs.stdenv.isx86_64) [ "-vga std" "-usb" "-device usb-tablet,bus=usb-bus.0" ])
        (mkIf (pkgs.stdenv.isAarch32 || pkgs.stdenv.isAarch64) [ "-device virtio-gpu-pci" "-device usb-ehci,id=usb0" "-device usb-kbd" "-device usb-tablet" ])
      ];
  
      # Mount the host filesystem via 9P, and bind-mount the Nix store
  
negative.code:       ''}
  
        cd $TMPDIR
        idx=0
        ${flip concatMapStrings cfg.emptyDiskImages (size: ''
          if ! test -e "empty$idx.qcow2"; then
              ${qemu}/bin/qemu-img create -f qcow2 "empty$idx.qcow2" "${toString size}M"
          fi
          idx=$((idx + 1))
        '')}
  
  