anchor.diff:  
       # 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" ])
  +      (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"
  +      ])
  +      (mkIf (!cfg.useBootLoader) [
  +        "-kernel ${config.system.build.toplevel}/kernel"
  +        "-initrd ${config.system.build.toplevel}/initrd"
  +        ''-append "$(cat ${config.system.build.toplevel}/kernel-params) init=${config.system.build.toplevel}/init regInfo=${regInfo}/registration ${consoles} $QEMU_KERNEL_PARAMS"''
  +      ])
  +      (mkIf cfg.useEFIBoot [
  +        "-pflash $TMPDIR/bios.bin"
  +      ])
  +      (mkIf (!cfg.graphics) [
  +        "-nographic"
  +      ])
  +    ];
  +
  +    virtualisation.qemu.drives = mkMerge [
  +      (mkIf cfg.useBootLoader [
  +        {
  +          file = "$NIX_DISK_IMAGE";
  +          driveExtraOpts.cache = "writeback";
  +          driveExtraOpts.werror = "report";
  +        }
  +        {
  +          file = "$TMPDIR/disk.img";
  +          driveExtraOpts.media = "disk";
  +          deviceExtraOpts.bootindex = "1";
  +        }
  +      ])
  +      (mkIf (!cfg.useBootLoader) [
  +        {
  +          file = "$NIX_DISK_IMAGE";
  +          driveExtraOpts.cache = "writeback";
  +          driveExtraOpts.werror = "report";
  +        }
  +      ])
  +      (imap0 (idx: _: {
  +        file = "$(pwd)/empty${toString idx}.qcow2";
  +        driveExtraOpts.werror = "report";
  +      }) cfg.emptyDiskImages)
       ];
   
       # Mount the host filesystem via 9P, and bind-mount the Nix store
  
positive.code:       ''}
  
        cd $TMPDIR
        idx=2
        extraDisks=""
        ${flip concatMapStrings cfg.emptyDiskImages (size: ''
          if ! test -e "empty$idx.qcow2"; then
              ${qemu}/bin/qemu-img create -f qcow2 "empty$idx.qcow2" "${toString size}M"
          fi
          extraDisks="$extraDisks ${mkDiskIfaceDriveFlag "$idx" "file=$(pwd)/empty$idx.qcow2,werror=report"}"
          idx=$((idx + 1))
        '')}
  
  
negative.code:           '';
          };
  
        drives =
          mkOption {
            type = types.listOf (types.submodule driveOpts);
            description = "Drives passed to qemu.";
          };
  
        diskInterface =
          mkOption {
            default = "virtio";
  