pvgrub_image: add package

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

pkgs/tools/misc/grub/2.0x.nix

···
 , zfs ? null
 , efiSupport ? false
 , zfsSupport ? true
+, xenSupport ? false
 }:
 
 with stdenv.lib;
···
 
 assert efiSupport -> canEfi;
 assert zfsSupport -> zfs != null;
+assert !(efiSupport && xenSupport);
 
 stdenv.mkDerivation rec {
   name = "grub-${version}";
···
   patches = [ ./fix-bash-completion.patch ];
 
   configureFlags = optional zfsSupport "--enable-libzfs"
-    ++ optionals efiSupport [ "--with-platform=efi" "--target=${efiSystemsBuild.${stdenv.system}.target}" "--program-prefix=" ];
+    ++ optionals efiSupport [ "--with-platform=efi" "--target=${efiSystemsBuild.${stdenv.system}.target}" "--program-prefix=" ]
+    ++ optionals xenSupport [ "--with-platform=xen" "--target=${efiSystemsBuild.${stdenv.system}.target}"];
 
   # save target that grub is compiled for
   grubTarget = if efiSupport

pkgs/tools/misc/grub/pvgrub_image/configs/grub-bootstrap.cfg

···
+normal (memdisk)/grub.cfg

pkgs/tools/misc/grub/pvgrub_image/configs/grub.cfg

···
+# The parentheses around ${root} here to match Grub's config file syntax
+if search -s -f /boot/grub/grub.cfg ; then
+        echo "Reading (${root})/boot/grub/grub.cfg"
+	configfile /boot/grub/grub.cfg
+fi
+
+if search -s -f /grub/grub.cfg ; then
+	echo "Reading (${root})/grub/grub.cfg"
+	configfile /grub/grub.cfg
+fi

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

···
+{ 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;
+  };
+})

pkgs/top-level/all-packages.nix

···
     zfsSupport = false;
   };
 
+  grub2_xen = callPackage ../tools/misc/grub/2.0x.nix {
+    xenSupport = true;
+  };
+
+  grub2_pvgrub_image = callPackage ../tools/misc/grub/pvgrub_image { };
+
   grub4dos = callPackage ../tools/misc/grub4dos {
     stdenv = stdenv_32bit;
   };