Re: [PATCH v8 20/40] x86/sev: Use SEV-SNP AP creation to start secondary CPUs

Borislav Petkov
2022-01-13T12:23:17Z

On Wed, Jan 12, 2022 at 11:10:04AM -0600, Tom Lendacky wrote:
> On 1/12/22 10:33 AM, Brijesh Singh wrote:
> > On 12/31/21 9:36 AM, Borislav Petkov wrote:
> > > On Fri, Dec 10, 2021 at 09:43:12AM -0600, Brijesh Singh wrote:
>
> > > > +     * an attempt was done to use the current VMSA with a running vCPU, a
> > > > +     * #VMEXIT of that vCPU would wipe out all of the settings being done
> > > > +     * here.
> > >
> > > I don't understand - this is waking up a CPU, how can it ever be a
> > > running vCPU which is using the current VMSA?!
>
> Yes, in general. My thought was that nothing is stopping a malicious
> hypervisor from performing a VMRUN on that vCPU and then the VMSA would be
> in use.

Ah, that's what you mean.

Ok, please extend that comment with it.

Thx.

--
Regards/Gruss,
Boris.