From patchwork Tue Jul 13 02:25:30 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zachary Amsden X-Patchwork-Id: 111634 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter.kernel.org (8.14.4/8.14.3) with ESMTP id o6D2SHxW015289 for ; Tue, 13 Jul 2010 02:28:17 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756520Ab0GMC0J (ORCPT ); Mon, 12 Jul 2010 22:26:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:20819 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754091Ab0GMC0F (ORCPT ); Mon, 12 Jul 2010 22:26:05 -0400 Received: from int-mx05.intmail.prod.int.phx2.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.18]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o6D2Q5fj018452 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 12 Jul 2010 22:26:05 -0400 Received: from mysore (vpn-10-168.rdu.redhat.com [10.11.10.168]) by int-mx05.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o6D2Pfif026035; Mon, 12 Jul 2010 22:26:03 -0400 From: Zachary Amsden To: KVM , Avi Kivity , Marcelo Tosatti , Glauber Costa Cc: Linux-kernel , Zachary Amsden , Avi Kivity , Marcelo Tosatti , Glauber Costa Subject: [PATCH 10/18] Keep SMP VMs more in sync on unstable TSC Date: Mon, 12 Jul 2010 16:25:30 -1000 Message-Id: <1278987938-23873-11-git-send-email-zamsden@redhat.com> In-Reply-To: <1278987938-23873-1-git-send-email-zamsden@redhat.com> References: <1278987938-23873-1-git-send-email-zamsden@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.18 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter.kernel.org [140.211.167.41]); Tue, 13 Jul 2010 02:28:17 +0000 (UTC) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 324e892..d9e0aa0 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -339,6 +339,7 @@ struct kvm_vcpu_arch { unsigned int time_offset; struct page *time_page; u64 last_host_tsc; + u64 last_host_ns; bool nmi_pending; bool nmi_injected; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 51d3f3e..a4d7cb9 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1888,8 +1888,13 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) native_read_tsc() - vcpu->arch.last_host_tsc; if (tsc_delta < 0) mark_tsc_unstable("KVM discovered backwards TSC"); - if (check_tsc_unstable()) + if (check_tsc_unstable()) { + /* Subtract elapsed cycle time */ + u64 ns = !vcpu->arch.last_host_ns ? 0 : + get_kernel_ns() - vcpu->arch.last_host_ns; + tsc_delta -= nsec_to_cycles(ns); kvm_x86_ops->adjust_tsc_offset(vcpu, -tsc_delta); + } kvm_migrate_timers(vcpu); kvm_request_guest_time_update(vcpu); vcpu->cpu = cpu; @@ -1901,6 +1906,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) kvm_x86_ops->vcpu_put(vcpu); kvm_put_guest_fpu(vcpu); vcpu->arch.last_host_tsc = native_read_tsc(); + vcpu->arch.last_host_ns = get_kernel_ns(); } static int is_efer_nx(void)