Comment # 13 on bug 1177009 from Fabian Vogt

(In reply to Michael Chang from comment #11)
> If there's no secure boot support required for ia32 and we used to come
> acorss some absurd x64 shipped with 32-bit efi firmware, maybe we should
> revert the last change made to i386-efi to make sure existing hardware can
> continue to work.
> 
> I am not sure whether this has any implication to kiwi again, since they
> might see different needs and prefer different "default"..
> 
> @Fabian,
> 
> What do you think ? Thanks in advanced.

So linuxefi on grub2-i386-efi is not able to boot the x86_64 Leap kernel?

Kiwi does this:

set linux=linux
set initrd=initrd
if [ "$${grub_cpu}" = "x86_64" -o "$${grub_cpu}" = "i386" ];then
    if [ "$${grub_platform}" = "efi" ]; then
        set linux=linuxefi
        set initrd=initrdefi
    fi
fi

Which is practically the same logic as in grub itself now with that patch.
If there's no reason to use the kernel efi stub on i386 (with an 32bit kernel),
I'm also in favor of just not using that there. This would need a change in
kiwi as well to remove the '-o "$${grub_cpu}" = "i386"', but I'm not aware of
any kiwi image with grub2-i386-efi currently, so it's not urgent.

(In reply to Michael Chang from comment #12)
> I have tested ovmf-ia32 and openSUSE Tumbleweed (64-bit)  booted fine with
> latest grub2-i386-efi (2.04-17.1) . The kernel version is 5.8.12-1-default.
> 
> Hi Neil
> 
> Just to make sure we're on the same page.
> 
> It is not clear to me. In comment#7 you described grub version 2.04-17.1 is
> broken, but you also mentioned that "In both cases, the broken version of
> grub2-i386-efi will boot the Tumbleweed 5.8 kernels, but fails to boot the
> Leap 5.3 kernels."
> 
> If some kernel works and others don't, maybe we have to include kernel team
> to help, or we just revert the change made to i386-efi (comment#11) given
> the 32-bit efi handover entry and 64/32 mixed mode is a bit too chaos that
> we probably need to do more test before switching.

Both Leap and TW kernels have CONFIG_EFI_MIXED=y, so it should work in theory.
It looks like there is some work on the 32->64 startup code in the TW kernel,
including
https://github.com/torvalds/linux/commit/17054f492dfd4d91e093ebb87013807812ec42a4#diff-9dda850e3f9dc2892fa064d7067c86f7,
but AFAICT it should've worked previously with efi handover as well.