[Xen-devel] /etc/grub.d/09-xen for generating grub.cfg for hypervisor boot entries.

[Bruce Edge <bruce.edge@xxxxxxxxx>]

If this has already been done, please forgive me. However, if not, I'd like to submit this as a mechanism for generating a bootable grub2 stanza for hypervisors.

As the /etc/grub.d/* files rely on defaults in /etc/default/grub, I added the following Xen specific variable:

GRUB_CMDLINE_XEN_DEFAULT="console=com1 115200,8n1 dom0_mem=512M dom0_max_vcpus=1 dom0_vcpus_pin=true iommu=1,passthrough,no-intremap loglvl=all loglvl_guest=all loglevl=10 debug acpi=force apic=on apic_verbosity=verbose numa=on"

The script itself is a hacked version of the10-linux that comes with grub2. This is 09-xen so it places it's boot entries ahead of the non-xen entries.

The resulting grub.cfg entry looks like:

### BEGIN /etc/grub.d/09_xen ###

  insmod lvm

  set root=(system-dom0_0)

menuentry "Xen osa-dom0 6.0.13-05, linux 2.6.32.12" {

        multiboot /boot/xen.gz /boot/xen.gz console=com1 115200,8n1 dom0_mem=512M dom0_max_vcpus=1 dom0_vcpus_pin=true iommu=1,passthrough,no-intremap loglvl=all loglvl_guest=all loglevl=10 debug acpi=force apic=on apic_verbosity=verbose numa=on

        module /boot/vmlinuz-2.6.32.12 /boot/vmlinuz-2.6.32.12 root=UUID=a3764d7d-6292-4f08-8ece-480e54c77229  ro earlyprintk=xen loglevel=10 debug acpi=force console=hvc0,115200n8

        module /boot/initrd.img-2.6.32.12 /boot/initrd.img-2.6.32.12

}

### END /etc/grub.d/09_xen ###

Note the duplication of the first params. I believe there's a bug that drops the 1st param so this could be changed later.

#! /bin/sh -e

prefix=/usr

exec_prefix=${prefix}

libdir=${exec_prefix}/lib

. ${libdir}/grub/update-grub_lib

if [ "x${GRUB_DISTRIBUTOR}" = "x" ] ; then

  OS=GNU/Linux

else

  OS="${GRUB_DISTRIBUTOR}"

fi

# Source grub defaults

. /etc/default/grub

# 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

  /dev/loop/*|/dev/loop[0-9])

    GRUB_DEVICE=`losetup ${GRUB_DEVICE} | sed -e "s/^[^(]*(\([^)]\+\)).*/\1/"`

  ;;

esac

if [ "x${GRUB_DEVICE_UUID}" = "x" ] || [ "x${GRUB_DISABLE_LINUX_UUID}" = "xtrue" ] \

    || ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" ; then

  LINUX_ROOT_DEVICE=${GRUB_DEVICE}

else

  LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}

fi

test_gt ()

{

  local a=`echo $1 | sed -e "s,.*/vmlinu[zx]-,,g;s/[._-]\(pre\|rc\|test\|git\|old\)/~\1/g"`

  local b=`echo $2 | sed -e "s,.*/vmlinu[zx]-,,g;s/[._-]\(pre\|rc\|test\|git\|old\)/~\1/g"`

  if [ "x$b" = "x" ] ; then

    return 0

  fi

  dpkg --compare-versions "$a" gt "$b"

  return $?

}

find_latest ()

{

  local a=""

  for i in $@ ; do

    if test_gt "$i" "$a" ; then

      a="$i"

    fi

  done

  echo "$a"

}

list=`for i in /boot/vmlinu[xz]-* /vmlinu[xz]-* ; do

        if grub_file_is_not_garbage "$i" ; then echo -n "$i " ; fi

      done`

while [ "x$list" != "x" ] ; do

  linux=`find_latest $list`

  echo "Found linux image: $linux" >&2

  basename=`basename $linux`

  dirname=`dirname $linux`

  rel_dirname=`make_system_path_relative_to_its_root $dirname`

  version=`echo $basename | sed -e "s,^[^0-9]*-,,g"`

  alt_version=`echo $version | sed -e "s,\.old$,,g"`

  linux_root_device_thisversion="${LINUX_ROOT_DEVICE}"

  initrd=

  for i in "initrd.img-${version}" "initrd-${version}.img" \

           "initrd.img-${alt_version}" "initrd-${alt_version}.img"; do

    if test -e "${dirname}/${i}" ; then

      initrd="$i"

      break

    fi

  done

  if test -n "${initrd}" ; then

    echo "Found initrd image: ${dirname}/${initrd}" >&2

  else

    # "UUID=" magic is parsed by initrds.  Since there's no initrd, it can't work here.

    linux_root_device_thisversion=${GRUB_DEVICE}

  fi

  cat << EOF

  insmod lvm

  set root=(system-dom0_0)

menuentry "Xen ${OS}, linux ${version}" {

        multiboot /boot/xen.gz /boot/xen.gz $GRUB_CMDLINE_XEN_DEFAULT

        module ${rel_dirname}/${basename} ${rel_dirname}/${basename} root=${linux_root_device_thisversion} $GRUB_CMDLINE_LINUX_DEFAULT

EOF

  if test -n "${initrd}" ; then

    cat << EOF

        module ${rel_dirname}/${initrd} ${rel_dirname}/${initrd}

EOF

  fi

  cat << EOF

}

EOF

  list=`echo $list | tr ' ' '\n' | grep -vx $linux | tr '\n' ' '`

done

-Bruce

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel