grub2/99-grub-mkconfig.install
Vitaly Kuznetsov 28040b73c9 99-grub-mkconfig: Avoid disabling BLS usage for Xen HVM VMs
Xen PV and PVH guest use direct kernel boot and may use 'pygrub' tool to
parse guest's grub config. The tool is incompatible with BLS and thus
99-grub-mkconfig.install disables it. The problem is observed with HVM
guests which are 'normal' VMs and don't require pygrub compatibility. E.g.
legacy AWS instance types are of this kind. Disabling BLS for them is
undesired and unjustified. Luckily, kernel driver for Xen provides
'/sys/hypervisor/guest_type' interface telling us which type of guest are
we running in.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
2024-07-02 13:58:10 +02:00

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#!/bin/bash
if ! [[ $KERNEL_INSTALL_MACHINE_ID ]]; then
exit 0
fi
# PV and PVH Xen DomU guests boot with pygrub that doesn't have BLS support,
# also Xen Dom0 use the menuentries from 20_linux_xen and not the ones from
# 10_linux. So BLS support needs to be disabled for both Xen Dom0 and DomU.
if [[ -e /sys/hypervisor/type ]] && grep -q "^xen$" /sys/hypervisor/type; then
if [ ! -e /sys/hypervisor/guest_type ] || ! grep -q "^HVM$" /sys/hypervisor/guest_type; then
RUN_MKCONFIG=true
DISABLE_BLS=true
fi
fi
ARCH=$(uname -m)
# Older ppc64le OPAL firmware (petitboot version < 1.8.0) don't have BLS support
# so grub2-mkconfig has to be run to generate a config with menuentry commands.
if [[ $ARCH = "ppc64le" ]] && [ -d /sys/firmware/opal ]; then
petitboot_path="/sys/firmware/devicetree/base/ibm,firmware-versions/petitboot"
if test -e ${petitboot_path}; then
read -r -d '' petitboot_version < ${petitboot_path}
petitboot_version="$(echo ${petitboot_version//v})"
major_version="$(echo ${petitboot_version} | cut -d . -f1)"
minor_version="$(echo ${petitboot_version} | cut -d . -f2)"
if test -z ${petitboot_version} || test ${major_version} -lt 1 || \
test ${major_version} -eq 1 -a ${minor_version} -lt 8; then
RUN_MKCONFIG=true
fi
else
RUN_MKCONFIG=true
fi
fi
if [[ $DISABLE_BLS = "true" ]]; then
if grep -q '^GRUB_ENABLE_BLSCFG="*true"*\s*$' /etc/default/grub; then
sed -i 's/^GRUB_ENABLE_BLSCFG=.*/GRUB_ENABLE_BLSCFG=false/' /etc/default/grub
fi
fi
# A traditional grub configuration file needs to be generated only in the case when
# the bootloaders are not capable of populating a menu entry from the BLS fragments.
if [[ $RUN_MKCONFIG != "true" ]]; then
exit 0
fi
[[ -f /etc/default/grub ]] && . /etc/default/grub
COMMAND="$1"
case "$COMMAND" in
add|remove)
grub2-mkconfig --no-grubenv-update -o /boot/grub2/grub.cfg >& /dev/null
;;
*)
;;
esac