Re: [PATCH 0/2] xen/efi: Make boot more flexible, especially with GRUB2

[Frediano Ziglio <frediano.ziglio@xxxxxxxxx>]

On Tue, Jun 24, 2025 at 9:32 AM Frediano Ziglio
<frediano.ziglio@xxxxxxxxx> wrote:
>
> The combination of GRUB2, EFI and UKI allows potentially more flexibility.
> For instance is possible to load xen.efi from a no ESP partition leaving
> a boot loader like GRUB2 taking care of the file loading.
> This however requires some changes in Xen to be less restrictive.
> Specifically for GRUB2 these changes allows the usage of "chainloader"
> command with UKI and reading xen.efi from no ESP (so no DeviceHandle
> set) and usage of "linux" and "initrd" commands to load separately
> the kernel (embedding using UKI) and initrd (using LoadFile2 protocol).

I was forgetting. If somebody wants to test "linux" and "initrd"
command with these changes be aware that GRUB currently has a problem
passing arguments, I posted a patch, see
https://lists.gnu.org/archive/html/grub-devel/2025-06/msg00156.html.
I also have a workaround for this issue in xen but it would be better
to have a fix in GRUB.

>
> Frediano Ziglio (2):
>   xen/efi: Handle cases where file didn't come from ESP
>   xen/efi: Support loading initrd using GRUB2 LoadFile2 protocol
>
>  xen/common/efi/boot.c     | 98 +++++++++++++++++++++++++++++++++++++--
>  xen/include/efi/efidevp.h | 21 +++++++++
>  2 files changed, 116 insertions(+), 3 deletions(-)