Re: [patch] x86/smpboot: Fix the parallel bringup decision

Kirill A. Shutemov
2023-05-31T11:08:10Z

On Wed, May 31, 2023 at 09:44:26AM +0200, Thomas Gleixner wrote:
> The decision to allow parallel bringup of secondary CPUs checks
> CC_ATTR_GUEST_STATE_ENCRYPT to detect encrypted guests. Those cannot use
> parallel bootup because accessing the local APIC is intercepted and raises
> a #VC or #VE, which cannot be handled at that point.
>
> The check works correctly, but only for AMD encrypted guests. TDX does not
> set that flag.
>
> As there is no real connection between CC attributes and the inability to
> support parallel bringup, replace this with a generic control flag in
> x86_cpuinit and let SEV-ES and TDX init code disable it.
>
> Fixes: 0c7ffa32dbd6 ("x86/smpboot/64: Implement arch_cpuhp_init_parallel_bringup() and enable it")
> Reported-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

--
Kiryl Shutsemau / Kirill A. Shutemov