pvgrub_image: add package

Add a package containing a pvgrub image for xen generated from grub2

pkgs/tools/misc/grub/pvgrub_image/default.nix

@@ -0,0 +1,42 @@
+{ stdenv, grub2_xen }:
+
+with stdenv.lib;
+let
+  efiSystemsBuild = {
+    "i686-linux".target = "i386";
+    "x86_64-linux".target = "x86_64";
+    "aarch64-linux".target = "aarch64";
+  };
+
+in (
+
+stdenv.mkDerivation rec {
+  name = "pvgrub-image";
+
+  configs = ./configs;
+
+  buildInputs = [ grub2_xen ];
+
+  buildCommand = ''
+    cp "${configs}"/* .
+    tar -cf memdisk.tar grub.cfg
+    # We include all modules except all_video.mod as otherwise grub will fail printing "no symbol table"
+    # if we include it.
+    grub-mkimage -O "${efiSystemsBuild.${stdenv.system}.target}-xen" -c grub-bootstrap.cfg \
+      -m memdisk.tar -o "grub-${efiSystemsBuild.${stdenv.system}.target}-xen.bin" \
+      $(ls "${grub2_xen}/lib/grub/${efiSystemsBuild.${stdenv.system}.target}-xen/" |grep 'mod''$'|grep -v '^all_video\.mod''$')
+    mkdir -p "$out/lib/grub-xen"
+    cp "grub-${efiSystemsBuild.${stdenv.system}.target}-xen.bin" $out/lib/grub-xen/
+  '';
+
+  meta = with stdenv.lib; {
+    description = "PvGrub image for use for booting PV Xen guests";
+
+    longDescription =
+      '' This package provides a PvGrub image for booting Para-Virtualized (PV)
+         Xen guests
+      '';
+
+    platforms = platforms.gnu;
+  };
+})