From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754368AbdJIMpH (ORCPT ); Mon, 9 Oct 2017 08:45:07 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:41795 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751741AbdJIMo4 (ORCPT ); Mon, 9 Oct 2017 08:44:56 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Jim Mattson" , "Radim =?UTF-8?Q?Kr=C4=8Dm=C3=A1=C5=99?=" Date: Mon, 09 Oct 2017 13:44:24 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 019/192] kvm: x86: Guest BNDCFGS requires guest MPX support In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.49-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jim Mattson commit 4439af9f911ae0243ffe4e2dfc12bace49605d8b upstream. The BNDCFGS MSR should only be exposed to the guest if the guest supports MPX. (cf. the TSC_AUX MSR and RDTSCP.) Fixes: 0dd376e709975779 ("KVM: x86: add MSR_IA32_BNDCFGS to msrs_to_save") Change-Id: I3ad7c01bda616715137ceac878f3fa7e66b6b387 Signed-off-by: Jim Mattson Signed-off-by: Radim Krčmář [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- arch/x86/kvm/cpuid.h | 8 ++++++++ arch/x86/kvm/vmx.c | 4 ++-- 2 files changed, 10 insertions(+), 2 deletions(-) --- a/arch/x86/kvm/cpuid.h +++ b/arch/x86/kvm/cpuid.h @@ -95,4 +95,13 @@ static inline bool guest_cpuid_has_gbpag best = kvm_find_cpuid_entry(vcpu, 0x80000001, 0); return best && (best->edx & bit(X86_FEATURE_GBPAGES)); } + +static inline bool guest_cpuid_has_mpx(struct kvm_vcpu *vcpu) +{ + struct kvm_cpuid_entry2 *best; + + best = kvm_find_cpuid_entry(vcpu, 7, 0); + return best && (best->ebx & bit(X86_FEATURE_MPX)); +} + #endif --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -2514,7 +2514,7 @@ static int vmx_get_msr(struct kvm_vcpu * data = vmcs_readl(GUEST_SYSENTER_ESP); break; case MSR_IA32_BNDCFGS: - if (!vmx_mpx_supported()) + if (!vmx_mpx_supported() || !guest_cpuid_has_mpx(vcpu)) return 1; data = vmcs_read64(GUEST_BNDCFGS); break; @@ -2587,7 +2587,7 @@ static int vmx_set_msr(struct kvm_vcpu * vmcs_writel(GUEST_SYSENTER_ESP, data); break; case MSR_IA32_BNDCFGS: - if (!vmx_mpx_supported()) + if (!vmx_mpx_supported() || !guest_cpuid_has_mpx(vcpu)) return 1; vmcs_write64(GUEST_BNDCFGS, data); break;