From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752732Ab0HTIP2 (ORCPT ); Fri, 20 Aug 2010 04:15:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:21992 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751740Ab0HTIIT (ORCPT ); Fri, 20 Aug 2010 04:08:19 -0400 From: Zachary Amsden To: kvm@vger.kernel.org Cc: Zachary Amsden , Avi Kivity , Marcelo Tosatti , Glauber Costa , Thomas Gleixner , John Stultz , linux-kernel@vger.kernel.org Subject: [KVM timekeeping 08/35] Warn about unstable TSC Date: Thu, 19 Aug 2010 22:07:22 -1000 Message-Id: <1282291669-25709-9-git-send-email-zamsden@redhat.com> In-Reply-To: <1282291669-25709-1-git-send-email-zamsden@redhat.com> References: <1282291669-25709-1-git-send-email-zamsden@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If creating an SMP guest with unstable host TSC, issue a warning Signed-off-by: Zachary Amsden --- arch/x86/kvm/x86.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) 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); } -- 1.7.1