On 14/11/2016 15:52, Radim Krčmář wrote: > The hunk below should return the same value in pvclock_ns and kernel_ns > if they can be used interchangeably. boot_ns is expected to be a bit > delayed, because it is read late. boot_ns shows a bounded offset from > kernel_ns, unlike the drifting pvclock_ns. > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 83990ad3710e..30d4d3d02ac7 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -6653,6 +6653,17 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) > goto cancel_injection; > } > > + if (vcpu->kvm->arch.use_master_clock) { > + s64 kernel_ns; > + cycle_t tsc_now, pvclock_ns, boot_ns; > + > + kvm_get_time_and_clockread(&kernel_ns, &tsc_now); > + pvclock_ns = __pvclock_read_cycles(&vcpu->arch.hv_clock, kvm_read_l1_tsc(vcpu, tsc_now)) - vcpu->kvm->arch.kvmclock_offset; > + boot_ns = ktime_get_boot_ns(); > + > + printk("ns diff: %lld %lld\n", pvclock_ns - kernel_ns, boot_ns - kernel_ns); > + } > + > preempt_disable(); > > kvm_x86_ops->prepare_guest_switch(vcpu); Ok, I'll post a v2 of this patch. Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html