From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752792AbeBXAwe (ORCPT ); Fri, 23 Feb 2018 19:52:34 -0500 Received: from mail-wm0-f67.google.com ([74.125.82.67]:52427 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752681AbeBXAwb (ORCPT ); Fri, 23 Feb 2018 19:52:31 -0500 X-Google-Smtp-Source: AG47ELvTW8/KuurPOgAEppRVwdeDgY5ccHymi+EW7S5X1QP3WGvo1zVMklxblV+x67TyV3PqfwYZEg== From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: David Woodhouse , KarimAllah Ahmed Subject: [PATCH] KVM: VMX: expose the host's ARCH_CAPABILITIES MSR to userspace Date: Sat, 24 Feb 2018 01:52:26 +0100 Message-Id: <1519433546-33879-1-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.8.3.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use the new MSR feature framework to expose the ARCH_CAPABILITIES MSR to userspace. This way, userspace can access the capabilities even if it does not have the permissions to read MSRs. Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx.c | 12 +++++++++++- arch/x86/kvm/x86.c | 1 + 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 130fca0ea1bf..99689061e11e 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -3228,7 +3228,17 @@ static inline bool vmx_feature_control_msr_valid(struct kvm_vcpu *vcpu, static int vmx_get_msr_feature(struct kvm_msr_entry *msr) { - return 1; + switch (msr->index) { + case MSR_IA32_ARCH_CAPABILITIES: + if (!boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES)) + return 1; + rdmsrl(msr->index, msr->data); + break; + default: + return 1; + } + + return 0; } /* diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 54b4ed55945b..e9a8cc9e3b2b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1054,6 +1054,7 @@ bool kvm_rdpmc(struct kvm_vcpu *vcpu) * can be used by a hypervisor to validate requested CPU features. */ static u32 msr_based_features[] = { + MSR_IA32_ARCH_CAPABILITIES, MSR_F10H_DECFG, }; -- 1.8.3.1