From patchwork Fri Aug 20 08:07:47 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zachary Amsden X-Patchwork-Id: 120516 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 o7K8BbSj003307 for ; Fri, 20 Aug 2010 08:12:11 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752419Ab0HTIJ2 (ORCPT ); Fri, 20 Aug 2010 04:09:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56711 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752463Ab0HTIJX (ORCPT ); Fri, 20 Aug 2010 04:09:23 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o7K89Jrf030226 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 20 Aug 2010 04:09:19 -0400 Received: from mysore (vpn-9-158.rdu.redhat.com [10.11.9.158]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o7K87qfR027969; Fri, 20 Aug 2010 04:09:17 -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 33/35] Indicate reliable TSC in kvmclock Date: Thu, 19 Aug 2010 22:07:47 -1000 Message-Id: <1282291669-25709-34-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> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 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]); Fri, 20 Aug 2010 08:12:11 +0000 (UTC) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 86f182a..a7fa24e 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -55,6 +55,7 @@ #include #include #include +#include #define MAX_IO_MSRS 256 #define CR0_RESERVED_BITS \ @@ -900,6 +901,13 @@ static void kvm_get_time_scale(uint32_t scaled_khz, uint32_t base_khz, static DEFINE_PER_CPU(unsigned long, cpu_tsc_khz); unsigned long max_tsc_khz; +static inline int kvm_tsc_reliable(void) +{ + return (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) && + boot_cpu_has(X86_FEATURE_NONSTOP_TSC) && + !check_tsc_unstable()); +} + static inline u64 nsec_to_cycles(struct kvm *kvm, u64 nsec) { return pvclock_scale_delta(nsec, kvm->arch.virtual_tsc_mult, @@ -1151,7 +1159,7 @@ static int kvm_guest_time_update(struct kvm_vcpu *v) vcpu->hv_clock.tsc_timestamp = tsc_timestamp; vcpu->hv_clock.system_time = kernel_ns + v->kvm->arch.kvmclock_offset; vcpu->last_kernel_ns = kernel_ns; - vcpu->hv_clock.flags = 0; + vcpu->hv_clock.flags = kvm_tsc_reliable() ? PVCLOCK_TSC_STABLE_BIT : 0; /* * The interface expects us to write an even number signaling that the