kernel/linux
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ synced 2026-11-10 20:48:12 +00:00
Code Issues Releases Packages Activity
No description
1,185,145 commits 117 branches 5,827 tags 6.3 GiB
  • C 96.8%
  • Assembly 0.9%
  • Rust 0.7%
  • Shell 0.6%
  • Python 0.5%
  • Other 0.3%
Find a file
Akihiro Suda 36e4fc57fc efi: Bump stub image version for macOS HVF compatibility 
The macOS hypervisor framework includes a host-side VMM called
VZLinuxBootLoader [1] which implements native support for booting the
Linux kernel inside a guest directly (instead of, e.g., via GRUB
installed inside the guest). On x86, it incorporates a BIOS style loader
that does not implement or expose EFI to the loaded kernel. However,
this loader appears to fail when the 'image minor version' field in the
kernel image's PE/COFF header (which is generally only used by EFI based
bootloaders) is set to any value other than 0x0. [2]

Commit e346bebbd3 ("efi: libstub: Always enable initrd command
line loader and bump version") incremented the EFI stub image minor
version to convey that all EFI stub kernels now implement support for
the initrd= command line option, and do so in a way where it can load
initrd images from any filesystem known to the EFI firmware (as opposed
to prior implementations that could only load initrds from the same
volume that the kernel image was loaded from).

Unfortunately, bumping the version to v1.1 triggers this issue in
VZLinuxBootLoader, breaking the boot on x86. So let's keep the image
minor version at 0x0, and bump the image major version instead.

While at it, convert this field to a bit field, so that individual
features are discoverable from it, as suggested by Linus. So let's bump
the major version to v3, and document the initrd= command line loading
feature as being represented by bit 1 in the mask.

Note that, due to the prior interpretation as a monotonically increasing
version field, loaders are still permitted to assume that the LoadFile2
initrd loading feature is supported for any major version value >= 1,
even if bit 0 is not set.

[1] https://developer.apple.com/documentation/virtualization/vzlinuxbootloader
[2] https://lore.kernel.org/linux-efi/CAG8fp8Teu4G9JuenQrqGndFt2Gy+V4YgJ=hN1xX7AD940YKf3A@mail.gmail.com/

Fixes: e346bebbd3 ("efi: libstub: Always enable initrd command ...")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217485
Signed-off-by: Akihiro Suda <suda.kyoto@gmail.com>
[ardb: rewrite comment and commit log]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
History 2023-05-28 20:45:46 +02:00
arch
block
certs
crypto
Documentation
drivers
fs
include
init
io_uring
ipc
kernel
lib
LICENSES
mm
net
rust
samples
scripts
security
sound
tools
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
.rustfmt.toml
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile
README

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.