kvm_check_tsc_unstable
if (kvm_check_tsc_unstable() && kvm->created_vcpus)
stable = !kvm_check_tsc_unstable();
if (!kvm_check_tsc_unstable()) {
if (unlikely(vcpu->cpu != cpu) || kvm_check_tsc_unstable()) {
if (kvm_check_tsc_unstable()) {