From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59D31C282CE for ; Tue, 4 Jun 2019 20:03:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2819B2070B for ; Tue, 4 Jun 2019 20:03:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726474AbfFDUDh (ORCPT ); Tue, 4 Jun 2019 16:03:37 -0400 Received: from mga01.intel.com ([192.55.52.88]:42568 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726179AbfFDUDh (ORCPT ); Tue, 4 Jun 2019 16:03:37 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Jun 2019 13:03:36 -0700 X-ExtLoop1: 1 Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.36]) by orsmga003.jf.intel.com with ESMTP; 04 Jun 2019 13:03:36 -0700 Date: Tue, 4 Jun 2019 13:03:36 -0700 From: Sean Christopherson To: Yang Weijiang Cc: pbonzini@redhat.com, mst@redhat.com, rkrcmar@redhat.com, jmattson@google.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, yu-cheng.yu@intel.com Subject: Re: [PATCH v5 5/8] KVM: VMX: Load Guest CET via VMCS when CET is enabled in Guest Message-ID: <20190604200336.GC7476@linux.intel.com> References: <20190522070101.7636-1-weijiang.yang@intel.com> <20190522070101.7636-6-weijiang.yang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190522070101.7636-6-weijiang.yang@intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 22, 2019 at 03:00:58PM +0800, Yang Weijiang wrote: > "Load Guest CET state" bit controls whether Guest CET states > will be loaded at Guest entry. Before doing that, KVM needs > to check if CPU CET feature is available to Guest. > > Note: SHSTK and IBT features share one control MSR: > MSR_IA32_{U,S}_CET, which means it's difficult to hide > one feature from another in the case of SHSTK != IBT, > after discussed in community, it's agreed to allow Guest > control two features independently as it won't introduce > security hole. > > Signed-off-by: Yang Weijiang > Co-developed-by: Zhang Yi Z > --- > arch/x86/kvm/vmx/vmx.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index 9321da538f65..1c0d487a4037 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -47,6 +47,7 @@ > #include > #include > #include > +#include Is this include actually needed? I haven't attempted to compile, but a glance everything should be in cpufeatures.h or vmx.h. > #include "capabilities.h" > #include "cpuid.h" > @@ -2929,6 +2930,17 @@ int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) > if (!nested_vmx_allowed(vcpu) || is_smm(vcpu)) > return 1; > } > + if (guest_cpuid_has(vcpu, X86_FEATURE_SHSTK) || > + guest_cpuid_has(vcpu, X86_FEATURE_IBT)) { > + if (cr4 & X86_CR4_CET) > + vmcs_set_bits(VM_ENTRY_CONTROLS, > + VM_ENTRY_LOAD_GUEST_CET_STATE); > + else > + vmcs_clear_bits(VM_ENTRY_CONTROLS, > + VM_ENTRY_LOAD_GUEST_CET_STATE); > + } else if (cr4 & X86_CR4_CET) { > + return 1; > + } Don't we also need to check for host CET support prior to toggling VM_ENTRY_LOAD_GUEST_CET_STATE? > > if (to_vmx(vcpu)->nested.vmxon && !nested_cr4_valid(vcpu, cr4)) > return 1; > -- > 2.17.2 >