Hi,
On 16/02/2023 18:18, Samuel Thibault wrote:
Andy Smith, le jeu. 16 févr. 2023 15:44:21 +0000, a ecrit:
- The PV part of grub is quite old and from what I understand
implemented in a strange way
Ah, uh :/
that no one wants to maintain any
more, so this part of grub is stuck without ability to
understand the newer kernel compressions.
I've been using the attached script to get around the problem. It tries
to decompress the cloud kernel and then recompress it with something
that grub-xen can handle. If recompression fails, it leaves an
uncompressed kernel, which also works, in place.
The script needs to be installed in /etc/kernel/postinst.d/.
--
Aleksi Suhonen
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#!/bin/sh
# SPDX-License-Identifier: GPL-2.0-only
# ----------------------------------------------------------------------
# kernel-recompress-hook - recompress cloud kernels for grub-xen
# Place this script in /etc/kernel/postinst.d/
# Requires: binutils, lz4, xz-utils
# (c) 2021-2023 Aleksi Suhonen <reportbug-2...@ssd.axu.tm>
#
# Distilled from extract-vmlinux by
# (c) 2009,2010 Dick Streefland <d...@streefland.net>
# (c) 2011 Corentin Chary <corentin.ch...@gmail.com>
#
# ----------------------------------------------------------------------
KERNEL_VERSION="$1"
KERNEL_PATH="$2"
# The KERNEL_PATH must be valid
if [ ! -f "${KERNEL_PATH}" ]; then
echo >&2 "Kernel file '${KERNEL_PATH}' not found. Aborting"
exit 1
fi
# Prepare temp files:
tmp=$(mktemp /boot/vmlinux-XXXXX)
trap "rm -f $tmp ${tmp}.xz" 0
# Try to find the LZ4 header and decompress from here
LZ4_HEADER="$(printf '\002!L\030')"
for pos in `fgrep -abo "$LZ4_HEADER" "$KERNEL_PATH"`
do
# grep counts bytes from 0, while tail counts from 1...
pos=$((1+${pos%%:*}))
rm -f $tmp
tail -c+$pos "$KERNEL_PATH" | lz4 -d >$tmp
readelf -h $tmp >/dev/null 2>&1 && break
echo "False LZ4 header at ${pos}, looking for more..."
done
if ! readelf -h $tmp > /dev/null; then
echo >&2 "Decompression of kernel file '${KERNEL_PATH}' failed!, not a
valid ELF image"
exit 0
fi
echo "Decompression of kernel file '${KERNEL_PATH}' successful"
if xz --check=crc32 --x86 --lzma2=dict=32MiB $tmp; then
echo "Recompression also successful"
mv -fv ${tmp}.xz ${KERNEL_PATH}
echo "Replacement of kernel file successful"
else
echo "Recompression unsuccessful"
mv -fv ${tmp} ${KERNEL_PATH}
echo "Replacement of kernel file successful"
fi
exit 0
#EOF
