[timekeeping,08/35] Warn about unstable TSC

Commit Message

Zachary Amsden Aug. 20, 2010, 8:07 a.m. UTC

None

Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3420f25..5e3b10e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5457,6 +5457,10 @@  void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
 struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
 						unsigned int id)
 {
+	if (check_tsc_unstable() && atomic_read(&kvm->online_vcpus) != 0)
+		printk_once(KERN_WARNING
+		"kvm: SMP vm created on host with unstable TSC; "
+		"guest TSC will not be reliable\n");
 	return kvm_x86_ops->vcpu_create(kvm, id);
 }