From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out3-smtp.messagingengine.com ([66.111.4.27]:35726 "EHLO out3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752743AbbIQFF6 (ORCPT ); Thu, 17 Sep 2015 01:05:58 -0400 Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by mailout.nyi.internal (Postfix) with ESMTP id A81B320F2D for ; Thu, 17 Sep 2015 01:05:57 -0400 (EDT) Subject: FAILED: patch "[PATCH] KVM: x86: Use adjustment in guest cycles when handling" failed to apply to 4.2-stable tree To: haozhong.zhang@intel.com, pbonzini@redhat.com Cc: From: Date: Wed, 16 Sep 2015 22:05:54 -0700 Message-ID: <1442466354171223@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: The patch below does not apply to the 4.2-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >>From d7add05458084a5e3d65925764a02ca9c8202c1e Mon Sep 17 00:00:00 2001 From: Haozhong Zhang Date: Fri, 7 Aug 2015 11:24:32 +0800 Subject: [PATCH] KVM: x86: Use adjustment in guest cycles when handling MSR_IA32_TSC_ADJUST When kvm_set_msr_common() handles a guest's write to MSR_IA32_TSC_ADJUST, it will calcuate an adjustment based on the data written by guest and then use it to adjust TSC offset by calling a call-back adjust_tsc_offset(). The 3rd parameter of adjust_tsc_offset() indicates whether the adjustment is in host TSC cycles or in guest TSC cycles. If SVM TSC scaling is enabled, adjust_tsc_offset() [i.e. svm_adjust_tsc_offset()] will first scale the adjustment; otherwise, it will just use the unscaled one. As the MSR write here comes from the guest, the adjustment is in guest TSC cycles. However, the current kvm_set_msr_common() uses it as a value in host TSC cycles (by using true as the 3rd parameter of adjust_tsc_offset()), which can result in an incorrect adjustment of TSC offset if SVM TSC scaling is enabled. This patch fixes this problem. Signed-off-by: Haozhong Zhang Cc: stable@vger.linux.org Signed-off-by: Paolo Bonzini diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c5e88a881899..8f0f6eca69da 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2105,7 +2105,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) if (guest_cpuid_has_tsc_adjust(vcpu)) { if (!msr_info->host_initiated) { s64 adj = data - vcpu->arch.ia32_tsc_adjust_msr; - kvm_x86_ops->adjust_tsc_offset(vcpu, adj, true); + adjust_tsc_offset_guest(vcpu, adj); } vcpu->arch.ia32_tsc_adjust_msr = data; }