kvm/x86: Hyper-V internal helper to read MSR HV_X64_MSR_TIME_REF_COUNT

This helper will be used also in Hyper-V SynIC timers implementation.
Signed-off-by: NAndrey Smetanin <asmetanin@virtuozzo.com>
Reviewed-by: NRoman Kagan <rkagan@virtuozzo.com>
CC: Gleb Natapov <gleb@kernel.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Haiyang Zhang <haiyangz@microsoft.com>
CC: Vitaly Kuznetsov <vkuznets@redhat.com>
CC: Roman Kagan <rkagan@virtuozzo.com>
CC: Denis V. Lunev <den@openvz.org>
CC: qemu-devel@nongnu.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/hyperv.c

@@ -335,6 +335,11 @@ static void synic_init(struct kvm_vcpu_hv_synic *synic)
 	}
 }
 
+static u64 get_time_ref_counter(struct kvm *kvm)
+{
+	return div_u64(get_kernel_ns() + kvm->arch.kvmclock_offset, 100);
+}
+
 void kvm_hv_vcpu_init(struct kvm_vcpu *vcpu)
 {
 	synic_init(vcpu_to_synic(vcpu));
@@ -576,11 +581,9 @@ static int kvm_hv_get_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
 	case HV_X64_MSR_HYPERCALL:
 		data = hv->hv_hypercall;
 		break;
-	case HV_X64_MSR_TIME_REF_COUNT: {
-		data =
-		     div_u64(get_kernel_ns() + kvm->arch.kvmclock_offset, 100);
+	case HV_X64_MSR_TIME_REF_COUNT:
+		data = get_time_ref_counter(kvm);
 		break;
-	}
 	case HV_X64_MSR_REFERENCE_TSC:
 		data = hv->hv_tsc_page;
 		break;