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This would allow x86 to > > continue to provide the DRTM trampolines through an EFI mechanism and > > means the Linux EFI stub always handles the launch with identical code > > in all scenarios. > > With some help from my friend Claude, I've prepared a prototype that > reuses my efiloader Rust crate to boot EFI stub images (bare Image, > zboot, UKI) in the kernel: the EFI boot phase is invoked at kexec > load time, and runs under the preceding kernel up until the point > where ExitBootServices() is called. Then, the actual kexec call > will return from ExitBootServices() after shutting down the first > kernel. Running it inside a kthread is such a novel idea, I would have never thought to attempt that! I've asked some folks here to take a look and try to test this with real DRTM capable HW. It seems very promising that it will work to me, and I surmize this is also close to boot a UKI? Seems amazing! Thanks a lot for drafting it! Jason