[PATCH v8 7/7] KVM: x86: Expose TSC offset controls to userspace

[Paolo Bonzini]

On 30/09/21 21:14, Marcelo Tosatti wrote:
>> +   new_off_n = t_0 + off_n + (k_1 - k_0) * freq - t_1
> Hi Oliver,
> 
> This won't advance the TSC values themselves, right?

Why not?  It affects the TSC offset in the vmcs, so the TSC in the VM is 
advanced too.

Paolo

> This (advancing the TSC values by the realtime elapsed time) would be
> awesome because TSC clock_gettime() vdso is faster, and some
> applications prefer to just read from TSC directly.
> See "x86: kvmguest: use TSC clocksource if invariant TSC is exposed".
> 
> The advancement with this patchset only applies to kvmclock.
>