From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f68.google.com ([74.125.82.68]:36301 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754098AbcGFNnW (ORCPT ); Wed, 6 Jul 2016 09:43:22 -0400 From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: stable@vger.kernel.org, Borislav Petkov Subject: [PATCH] KVM: SVM: fix trashing of MSR_TSC_AUX Date: Wed, 6 Jul 2016 15:43:16 +0200 Message-Id: <1467812596-18903-1-git-send-email-pbonzini@redhat.com> Sender: stable-owner@vger.kernel.org List-ID: I don't know what I was thinking when I wrote commit 46896c73c1a4 ("KVM: svm: add support for RDTSCP", 2015-11-12); I missed write_rdtscp_aux which obviously uses MSR_TSC_AUX. Therefore we do need to save/restore MSR_TSC_AUX in svm_vcpu_run. Cc: stable@vger.kernel.org Cc: Borislav Petkov Fixes: 46896c73c1a4 ("KVM: svm: add support for RDTSCP") Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 16ef31b87452..44f6368f8b45 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -43,6 +43,7 @@ #include #include +#include #include "trace.h" #define __ex(x) __kvm_handle_fault_on_reboot(x) @@ -1530,9 +1531,6 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu) wrmsrl(MSR_AMD64_TSC_RATIO, tsc_ratio); } } - /* This assumes that the kernel never uses MSR_TSC_AUX */ - if (static_cpu_has(X86_FEATURE_RDTSCP)) - wrmsrl(MSR_TSC_AUX, svm->tsc_aux); avic_vcpu_load(vcpu, cpu); } @@ -4474,6 +4472,8 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) svm->vmcb->save.cr2 = vcpu->arch.cr2; clgi(); + if (static_cpu_has(X86_FEATURE_RDTSCP)) + wrmsrl(MSR_TSC_AUX, svm->tsc_aux); local_irq_enable(); @@ -4550,6 +4550,8 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) #endif ); + if (static_cpu_has(X86_FEATURE_RDTSCP)) + wrmsrl(MSR_TSC_AUX, __getcpu()); #ifdef CONFIG_X86_64 wrmsrl(MSR_GS_BASE, svm->host.gs_base); #else -- 1.8.3.1