[PATCH v3 0/3] xen/efi: Make boot more flexible, especially with GRUB2

[Frediano Ziglio <frediano.ziglio@cloud.com>]

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).

Changes since v1:
- keep read_file fatal when it was so;
- attempt to use LoadFile2 after trying object section;
- minor changes (see details on specific changes).

Changes since v2:
- update read_file style;
- added acked-by.

Frediano Ziglio (3):
  xen/efi: Handle cases where file didn't come from ESP
  xen/efi: Support loading initrd using GRUB2 LoadFile2 protocol
  xen/efi: Update error flow for read_file function

 xen/common/efi/boot.c     | 179 +++++++++++++++++++++++++++++---------
 xen/include/efi/efidevp.h |  21 +++++
 2 files changed, 160 insertions(+), 40 deletions(-)

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2.43.0