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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 ED164C55186 for ; Sat, 25 Apr 2020 09:12:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D4E172064A for ; Sat, 25 Apr 2020 09:12:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726092AbgDYJMW (ORCPT ); Sat, 25 Apr 2020 05:12:22 -0400 Received: from mga05.intel.com ([192.55.52.43]:28431 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726022AbgDYJMV (ORCPT ); Sat, 25 Apr 2020 05:12:21 -0400 IronPort-SDR: mTEam8Lk2NrokMK8wOfbV6VhW2AbJXF5kMvjvUxkuRfD4C2sB46g5dy6wRYsGm3y73FAw/tBjj tfwXYP3hEsnw== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Apr 2020 02:12:21 -0700 IronPort-SDR: Q3anePwXL0+gercRC5wVBvj8vvjE3OueL9ys+ji1dbPh2wObZrI00tjx2pAim3gjXwpodckd1n zsZ0Whi9cZvg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,315,1583222400"; d="scan'208";a="274898307" Received: from unknown (HELO localhost) ([10.239.159.128]) by orsmga002.jf.intel.com with ESMTP; 25 Apr 2020 02:12:19 -0700 Date: Sat, 25 Apr 2020 17:14:19 +0800 From: Yang Weijiang To: Sean Christopherson Cc: Yang Weijiang , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, pbonzini@redhat.com, jmattson@google.com, yu.c.zhang@linux.intel.com Subject: Re: [PATCH v11 2/9] KVM: VMX: Set guest CET MSRs per KVM and host configuration Message-ID: <20200425091419.GA26221@local-michael-cet-test> References: <20200326081847.5870-1-weijiang.yang@intel.com> <20200326081847.5870-3-weijiang.yang@intel.com> <20200423162749.GG17824@linux.intel.com> <20200424140751.GE24039@local-michael-cet-test> <20200424145529.GD30013@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200424145529.GD30013@linux.intel.com> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 24, 2020 at 07:55:29AM -0700, Sean Christopherson wrote: > On Fri, Apr 24, 2020 at 10:07:51PM +0800, Yang Weijiang wrote: > > On Thu, Apr 23, 2020 at 09:27:49AM -0700, Sean Christopherson wrote: > > > On Thu, Mar 26, 2020 at 04:18:39PM +0800, Yang Weijiang wrote: > > > > @@ -7102,6 +7138,10 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu) > > > > vmx_set_guest_msr(vmx, msr, enabled ? 0 : TSX_CTRL_RTM_DISABLE); > > > > } > > > > } > > > > + > > > > + if (guest_cpuid_has(vcpu, X86_FEATURE_SHSTK) || > > > > + guest_cpuid_has(vcpu, X86_FEATURE_IBT)) > > > > + vmx_update_intercept_for_cet_msr(vcpu); > > > > > > This is wrong, it will miss the case where userspace double configures CPUID > > > and goes from CET=1 to CET=0. This should instead be: > > > > > > if (supported_xss & (XFEATURE_MASK_CET_KERNEL | XFEATURE_MASK_CET_USER)) > > > vmx_update_intercept_for_cet_msr(vcpu); > > > > > > > } > > Here CET=1/0, did you mean the CET bit in XSS or CR4.CET? If it's the > > former, then it's OK for me. > > The former, i.e. update the CET MSRs if KVM supports CET virtualization and > the guest's CPUID configuration is changing. Yep, this case should be taken into account, thank you for pointing it out!