On Mon, Jan 16, 2023 at 03:25:34PM +0100, Peter Zijlstra wrote: > The boot trampolines from trampoline_64.S have code flow like: > > 16bit BIOS SEV-ES 64bit EFI > > trampoline_start() sev_es_trampoline_start() > trampoline_start_64() > verify_cpu() | | > switch_to_protected: <---------------' v > | > pa_trampoline_compat() > v | > startup_32() > <-----------------------------------------------' > | > v > startup_64() > | > v > tr_start() := head_64.S:secondary_startup_64() > > Since AP bringup always goes through the 16bit BIOS path (EFI doesn't > touch the APs), there is already a verify_cpu() invocation.
So supposedly TDX/ACPI-6.4 comes in on trampoline_startup64() for APs -- can any of the TDX capable folks tell me if we need verify_cpu() on these? Aside from checking for LM, it seems to clear XD_DISABLE on Intel and force enable SSE on AMD/K7. Surely none of that is needed for these shiny new chips? I mean, I can hack up a patch that adds verify_cpu() to the 64bit entry point, but it seems really sad to need that on modern systems.
