Re: [PATCH 0/1] x86/kexec: UKI support

[Jarkko Sakkinen]

On Tue Sep 12, 2023 at 6:32 PM EEST, Jan Hendrik Farr wrote:
> >> The format itself is rather simple. It's just a PE file (as required
> >> by the UEFI spec) that contains a small stub application in the .text,
> >> .data, etc sections that is responsible for invoking the contained
> >> kernel and initrd with the contained cmdline. The kernel image is
> >> placed into a .kernel section, the initrd into a .initrd section, and
> >> the cmdline into a .cmdline section in the PE executable.
> >
> > How does this interact with the existing EFI stub support in linux?
>
> It doesn't. During normal boot of a UKI the stub in it is used
> (systemd-stub, see:
> https://www.freedesktop.org/software/systemd/man/systemd-stub.html).
> The kernel's own EFI stub will still be in the binary inside the
> .linux section but not used.

What sort of bottleneck does the EFI stub have so that we need yet
another envelope?

BR, Jarkko