Re: [PATCH v3 6/9] x86/smpboot: Support parallel startup of secondary CPUs

[Tom Lendacky]

On 12/16/21 12:24 PM, David Woodhouse wrote:
> On Thu, 2021-12-16 at 08:24 -0600, Tom Lendacky wrote:
>
> > This will break an SEV-ES guest because CPUID will generate a #VC and a
> > #VC handler has not been established yet.
> >
> > I guess for now, you can probably just not enable parallel startup for
> > SEV-ES guests.
>
> OK, thanks. I'll expand it to allow 24 bits of (physical) APIC ID then,
> since it's no longer limited to CPUs without X2APIC. Then we can
> refrain from doing parallel bringup for SEV-ES guests, as you suggest.
>
> What precisely is the check I should be using for that?

Calling cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT) will return true for 
an SEV-ES guest.

Thanks,
Tom

>