Messages in this thread | | | Date | Wed, 18 Jan 2023 10:45:44 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2 1/7] x86/boot: Remove verify_cpu() from secondary_startup_64() |
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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.
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