On Sat, Aug 05, 2023 at 07:37:17PM +0200, Ard Biesheuvel wrote: > So this is the host booting, right? Yes. > So is the position of the C bit perhaps getting detect incorrectly? I don't know yet. But the evildoer is someone else: 02d47ce2ae02 ("x86/head_64: Store boot_params pointer in callee save register") after bisection. More staring later as to why... -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette