From: Raymund Will <rw@suse.com>
Subject: Use chainloader to boot xen.efi under UEFI.
References: bnc#871857, bnc#879148
Patch-Mainline: no

As XEN on SLE12 is not multiboot2 ready, some very dirty hacking
is necessary to boot via xen.efi and separate configfile snippets
(as done in SLE11SP3 secureboot).

To that end said configfile snippets, xen efi-binaries, kernels and initrds
need to copied to the EFI system partition during 'grub2-mkconfig'!

V0:
- first, somewhat fragile version, without any sort of cleanup for ESP.
V1:
- add missing whitespace.  (bnc879148)
V2:
- second, much less fragile version, using only one config file per
  XEN hypervisor version with sections for different kernels, avoiding
  useless duplicates for sym-linked hypervisors. and removing previously
  installed files from ESP.
V3:
- support move to '/usr/share/efi/$machine' for EFI-binaries. (bsc#1122563)

---
 util/grub.d/20_linux_xen.in |  109 +++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 97 insertions(+), 12 deletions(-)

--- a/util/grub.d/20_linux_xen.in
+++ b/util/grub.d/20_linux_xen.in
@@ -21,6 +21,8 @@
 exec_prefix="@exec_prefix@"
 datarootdir="@datarootdir@"
 
+ME=$(basename $0)
+
 . "$pkgdatadir/grub-mkconfig_lib"
 
 export TEXTDOMAIN=@PACKAGE@
@@ -36,11 +38,23 @@
 
 if [ "x${GRUB_DISTRIBUTOR}" = "x" ] ; then
   OS=GNU/Linux
+  os=linux
 else
   OS="${GRUB_DISTRIBUTOR}"
-  CLASS="--class $(echo ${GRUB_DISTRIBUTOR} | tr 'A-Z' 'a-z' | cut -d' ' -f1|LC_ALL=C sed 's,[^[:alnum:]_],_,g') ${CLASS}"
+  os="$(echo ${GRUB_DISTRIBUTOR} | tr 'A-Z' 'a-z' | cut -d' ' -f1)"
+  CLASS="--class ${os} ${CLASS}"
 fi
 
+machine=`uname -m`
+
+case "$machine" in
+    i?86) GENKERNEL_ARCH="x86" ;;
+    mips|mips64) GENKERNEL_ARCH="mips" ;;
+    mipsel|mips64el) GENKERNEL_ARCH="mipsel" ;;
+    arm*) GENKERNEL_ARCH="arm" ;;
+    *) GENKERNEL_ARCH="$machine" ;;
+esac
+
 # loop-AES arranges things so that /dev/loop/X can be our root device, but
 # the initrds that Linux uses don't like that.
 case ${GRUB_DEVICE} in
@@ -99,6 +113,32 @@
 
 title_correction_code=
 
+if [ -d /sys/firmware/efi ]; then
+  is_efi=true
+  err_msg=""
+  efi_dir="/boot/efi/efi/${os}"
+  grub_dir=/boot/@PACKAGE@
+  xen_dir=/usr/share/efi/$machine
+  [ -d $xen_dir ] || xen_dir=/usr/lib64/efi
+  for d in $grub_dir $efi_dir $xen_dir; do
+    [ ! -d "$d" ] || continue
+    err_msg="${err_msg}$ME: Essential directory '$d' not found!\n"
+  done
+  if ! [ -d "$efi_dir" -a -d "$grub_dir" -a -d "$xen_dir" ]; then
+    err_msg="${err_msg}$ME: XEN configuration skipped!\n"
+  else
+    rm -f  $grub_dir/xen*.cfg
+    if [ -s $efi_dir/grub.xen-files ]; then
+      for f in $(sort $efi_dir/grub.xen-files| uniq); do
+	rm -f $efi_dir/$f
+      done
+      : > $efi_dir/grub.xen-files
+    fi
+  fi
+else
+  is_efi=false
+fi
+
 linux_entry ()
 {
   linux_entry_xsm "$@" false
@@ -154,6 +194,40 @@
       save_default_entry | grub_add_tab | sed "s/^/$submenu_indentation/"
   fi
 
+  if $is_efi; then
+    xen_cfg=${xen_basename/.efi/.cfg}
+    if [ "$section_count" = 0 ]; then
+      cat <<-EOF > $grub_dir/$xen_cfg
+	# disclaimer
+	[global]
+	#default=
+	EOF
+    fi
+    section_count=$(expr $section_count + 1)
+    if [ x$type != xrecovery ] ; then
+      section="config.$section_count"
+    else
+      section="failsafe.$section_count"
+    fi
+    cat <<-EOF >> $grub_dir/$xen_cfg
+
+	[$section]
+	options=${xen_args}
+	kernel=${basename} root=${linux_root_device_thisversion} ${args}
+	ramdisk=${initrd_real}
+	EOF
+    message="$(gettext_printf "Loading Xen %s with Linux %s ..." ${xen_version} ${version})"
+    sed "s/^/$submenu_indentation/" <<-EOF
+	 	echo	'$(echo "$message" | grub_quote)'
+	 	chainloader  \$cmdpath/${xen_basename} ${xen_basename} $section
+	}
+	EOF
+    for f in ${grub_dir}/$xen_cfg ${xen_dir}/${xen_basename} ${dirname}/${basename} ${dirname}/${initrd_real}; do
+      cp --preserve=timestamps $f $efi_dir
+      echo $(basename $f) >> $efi_dir/grub.xen-files
+    done
+    return
+  fi
   if [ -z "${prepare_boot_cache}" ]; then
     prepare_boot_cache="$(prepare_grub_to_access_device ${GRUB_DEVICE_BOOT} | grub_add_tab)"
   fi
@@ -245,16 +319,6 @@
 
 title_correction_code=
 
-machine=`uname -m`
-
-case "$machine" in
-    i?86) GENKERNEL_ARCH="x86" ;;
-    mips|mips64) GENKERNEL_ARCH="mips" ;;
-    mipsel|mips64el) GENKERNEL_ARCH="mipsel" ;;
-    arm*) GENKERNEL_ARCH="arm" ;;
-    *) GENKERNEL_ARCH="$machine" ;;
-esac
-
 # Extra indentation to add to menu entries in a submenu. We're not in a submenu
 # yet, so it's empty. In a submenu it will be equal to '\t' (one tab).
 submenu_indentation=""
@@ -325,6 +389,24 @@
     xen_dirname=`dirname ${current_xen}`
     rel_xen_dirname=`make_system_path_relative_to_its_root $xen_dirname`
     xen_version=`echo $xen_basename | sed -e "s,.gz$,,g;s,^xen-,,g"`
+    xen_list=`echo $xen_list | tr ' ' '\n' | grep -vx $current_xen | tr '\n' ' '`
+    if $is_efi; then
+      xen_basename=${xen_basename/.gz/.efi}
+      if ! [ -f ${xen_dir}/${xen_basename} ]; then
+	echo "Skip missing hypervisor $xen_dir/$xen_basename" >&2
+	continue
+      elif [ -L ${xen_dir}/${xen_basename} ]; then
+	xen_target=$(basename $(readlink -e ${xen_dir}/${xen_basename}))
+	if [ -f ${efi_dir}/${xen_target} ]; then
+	  echo "Skip duplicate $xen_dir/$xen_basename for $xen_target" >&2
+	  continue
+	fi
+      elif [ -n "$err_msg" ]; then
+	break
+      fi
+      gettext_printf "Found hypervisor: %s\n" "$current_xen" >&2
+      section_count=0
+    fi
     if [ -z "$boot_device_id" ]; then
 	boot_device_id="$(grub_get_device_id "${GRUB_DEVICE}")"
     fi
@@ -445,3 +527,7 @@
 fi
 
 echo "$title_correction_code"
+
+if [ -n "$err_msg" ]; then
+  echo -en "$err_msg" >&2
+fi