Re: [PATCH 3/4] KVM: x86: introduce get_kvmclock_ns
From: Roman Kagan
Date: Fri Sep 02 2016 - 13:08:29 EST
On Fri, Sep 02, 2016 at 06:57:10PM +0200, Paolo Bonzini wrote:
>
>
> On 02/09/2016 18:55, Roman Kagan wrote:
> >> > I'll change patch 4 to store the parameters and use them when accessing
> >> > the time reference counter MSR. I'll still keep the procedure that goes
> >> > through kvmclock. It's a bit more involved for the scale, but
> >> > vcpu->last_guest_tsc only provides a part of the offset computation; the
> >> > other half is vcpu->hv_clock.system_time and it's not stored anywhere.
> > Erm... It is stored right there, in vcpu->hv_clock.system_time, you can
> > access it just fine when you populate tsc_ref_page values. Am I missing
> > anything?
>
> No. It's not stored anywhere outside vcpu->hv_clock. My reasoning goes
> that if I have to use vcpu->hv_clock.system_time I might as well use
> vcpu->hv_clock for everything. :)
Well, there're plenty of ways to bring the necessary values to where
they are needed.
But that's a matter of simplicity, not correctness, so I won't mind that
much.
Thanks,
Roman.