Re: [PATCH] Allow RDTSC and RDTSCP from userspace

[Tom Lendacky]

On 4/24/20 4:24 PM, Dave Hansen wrote:
> On 4/24/20 2:03 PM, Mike Stunes wrote:
> > I needed to allow RDTSC(P) from userspace and in early boot in order to
> > get userspace started properly. Patch below.
> >
> > ---
> > SEV-ES guests will need to execute rdtsc and rdtscp from userspace and
> > during early boot. Move the rdtsc(p) #VC handler into common code and
> > extend the #VC handlers.
>
> Do SEV-ES guests _always_ #VC on rdtsc(p)?

Only if the hypervisor is intercepting those instructions.

Thanks,
Tom

>