Re: [PATCH v4 00/10] make L2's kvm-clock stable, get rid of pvclock_gtod_copy in KVM

John Stultz
2017-08-22T19:50:06Z

On Mon, Aug 21, 2017 at 1:40 AM, Denis Plotnikov
<dplotnikov@virtuozzo.com> wrote:
> ping!
>

I still don't feel my questions have been well answered. Its really
not clear to me why, in order to allow the level-2 guest to use a vdso
that the answer is to export more data through the entire stack rather
then to make the kvmclock to be usable from the vsyscall.

So far for a problem statement, all I've got is:
"However, when using nested virtualization you have

L0: bare-metal hypervisor (uses TSC)
L1: nested hypervisor (uses kvmclock, can use vsyscall)
L2: nested guest

and L2 cannot use vsyscall because it is not using the TSC."

Which is a start but doesn't really make it clear why the proposed
solution is best/necessary.

thanks
-john