On Tue, Nov 30, 2021 at 07:21:42AM +0100, Juergen Gross via Grub-devel wrote: > On 30.11.21 00:25, Shaun Reitan wrote: > > I currently use XEN to boot PV (paravirt) virtual server instances for > > our customers. Grub2 introduced support for booting a xen kernel > > directly from a guests disk image which has worked great for years. We > > use the following command to build our image > > > > grub-mkstandalone -O x86_64-xen -o grub2-x86_64.gz boot/grub/grub.cfg > > > > What we have been seeing more and more is newer distros like Ubuntu > > 20.04 using lz4 compressed kernel images which will not boot and > > displays the error "not xen image." > > > > If i use the > > https://raw.githubusercontent.com/torvalds/linux/master/scripts/extract-vmlinux > > > > <https://raw.githubusercontent.com/torvalds/linux/master/scripts/extract-vmlinux> > > utility > > to decompress the kernel image I am able to boot it without any issues > > using our current grub2 xen loader. > > > > My question is how can I get lz4 support added into grub2 for xen? We > > are willing to pay for a dev to add this support if needed as I have > > limited time to really dig into this. > > > > There are a few workarounds out their, most involve a hook that > > decompresses the kernel after an update but I'm not wanting to add > > complexity to the kernel update process. It leaves too much room for > > error and the possibility of a clients server failing to boot after what > > should of been a simple kernel upgrade. > > > > Any help, even if just pointing me in the right direction would be > > appreciated! > > Hmm, Grub2 already supports some compression methods, so adding LZ4 > shouldn't be that hard. Especially as there already is some LZ4 > support hidden in the ZFS handling. > > I guess this LZ4 support wants to be put into a grub module of its > own and then be added to the filter list. > > You should have a look at: > > - GRUB_FILE_FILTER_GZIO for an example how a compression filter is > added via grub_file_filter_register() > > - the file grub-core/fs/zfs/zfs_lz4.c for current LZ4 support in > Grub2 > > This should basically do the job. > > I've added Daniel to Cc: as he might have some more thoughts.
Yeah, in general I agree. However, I would look for an LZ4 library which could be merged with the GRUB code, licensing compatibility is important here, and is under active development/maintenance. If there is no such we can reuse ZFS LZ4 code. Daniel _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
