On Sat, Oct 6, 2018 at 1:29 PM Marcelo Tosatti <mtosatti@xxxxxxxxxx> wrote: > > On Thu, Oct 04, 2018 at 03:15:32PM -0700, Andy Lutomirski wrote: > > For better or for worse, I'm trying to understand this code. So far, > > I've come up with this patch: > > > > https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git/commit/?h=x86/vdso-tglx&id=14fd71e12b1c4492a06f368f75041f263e6862bf > > > > Is it correct, or am I missing some subtlety? > > The master clock, when initialized, has a pair > > masterclockvalues=(TSC value, time-of-day data). > > When updating the guest clock, we only update relative to (TSC value) > that was read on masterclock initialization. I don't see the problem. The masterclock data is updated here: host_tsc_clocksource = kvm_get_time_and_clockread( &ka->master_kernel_ns, &ka->master_cycle_now); kvm_get_time_and_clockread() gets those values from do_monotonic_boot(), which, barring bugs, should cause get_kvmclock_ns() to return exactly the same thing as ktime_get_boot_ns() + ka->kvmclock_offset, albeit in a rather roundabout manner. So what am I missing? Is there actually something wrong with my patch? > > See the following comment on x86.c: I read that comment, and it's not obvious to me how it's related. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
