CONFIG_EFI_ZBOOT causing missing vmlinuz from tarball builds

[Ard Biesheuvel]

(cc Will)

On Tue, 13 Dec 2022 at 17:56, Veronika Kabatova <vkabatov at redhat.com> wrote:
>
> Hello!
>
> We (CKI Project) have recently tried a kernel build with the
> CONFIG_EFI_ZBOOT option enabled, and got surprised by
> our kernel install and boot scripts getting unhappy. After some
> debugging it seems like the reason is the combination of the
> option with the tarball build target.
>
>
> When the option is enabled, Image.gz doesn't get generated
> and vmlinuz.efi binary is created instead. This binary name is
> not in the list of binaries that get packaged into the tarball:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/package/buildtar#n125
>
> My noob solution would be to add vmlinuz.efi into the list of
> acceptable files in the line above, but I'm not familiar with
> the functionality this new binary offers and whether that is
> an acceptable solution. I can send a patch if it is, but if there
> is more nuance to the fix could someone please take a look?
>

Hello Veronika,

Thanks for the report.

I agree adding vmlinuz.efi to the tarball seems like a sensible
solution here, but I'm not 100% sure I understand how this tarball is
consumed.

The EFI zboot target needs testing coverage as well, of course, so I
am happy that you are looking into this. But for actual production
use, it is mostly intended for distros that only support EFI boot and
want to sign the bootable images for EFI secure boot, which is
currently a bit of a pain with the plain gzip'ed images. So whether or
not building the tarball with the EFI zboot image is a meaningful
combination is not 100% clear to me.

Kind regards,
Ard.