On 04/08/2025 10:34 am, Jan Beulich wrote: > On 24.07.2025 16:07, Yann Sionneau wrote: >> xen.efi PE does not boot when loaded from shim or some patched >> downstream grub2. >> >> What happens is the bootloader would honour the MEM_DISCARDABLE >> flag of the .reloc section meaning it would not load its content >> into memory. >> >> But Xen is parsing the .reloc section content twice at boot: >> * https://elixir.bootlin.com/xen/v4.20.1/source/xen/common/efi/boot.c#L1362 >> * >> https://elixir.bootlin.com/xen/v4.20.1/source/xen/arch/x86/efi/efi-boot.h#L237 >> >> Therefore it would crash with the following message: >> "Unsupported relocation type" as reported there: >> >> * https://github.com/QubesOS/qubes-issues/issues/8206#issuecomment-2619048838 >> * >> https://lore.kernel.org/xen-devel/7e039262-1f54-46e1-8f70-ac3f03607...@suse.com/T/#me122b9e6c27cd98db917da2c9f67e74a2c6ad7a5 >> >> This commit adds a small C host tool named keeprelocs >> that is called after xen.efi is produced by the build system >> in order to remove this bit from its .reloc section header. >> >> Signed-off-by: Yann Sionneau <yann.sionn...@vates.tech> > So I found a way to deal with this at the linker side, without any new command > line options. Behavior is solely driven by the attributes of any incoming > .reloc > sections (of which there would be none by default, retaining original > behavior). > The important patch is [1], but at least the first patch of the series [2] > would > in most cases also be wanted/needed (patch 04 is obviously a mechanical prereq > for the main patch). Need for other of the prereqs there depends on the scope > and purpose of one's binutils build(s). > > Jan > > [1] https://sourceware.org/pipermail/binutils/2025-August/143153.html > [2] https://sourceware.org/pipermail/binutils/2025-August/143141.html
That's good to see. Do we need any matching changes in Xen? ~Andrew
