From 6755bae8e69093b2994b6f29cd3eaecdf610374e Mon Sep 17 00:00:00 2001 From: Zachary Amsden Date: Thu, 19 Aug 2010 22:07:22 -1000 Subject: [PATCH] KVM: x86: Warn about unstable TSC If creating an SMP guest with unstable host TSC, issue a warning Signed-off-by: Zachary Amsden Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/x86.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 699c6b89c1b4..a8dee58e8716 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); }