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=-7.7 required=3.0 tests=DATE_IN_PAST_12_24, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,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 AD577C43381 for ; Tue, 5 Mar 2019 03:17:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 83488206B6 for ; Tue, 5 Mar 2019 03:17:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726992AbfCEDQ7 (ORCPT ); Mon, 4 Mar 2019 22:16:59 -0500 Received: from mga11.intel.com ([192.55.52.93]:12474 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726522AbfCEDQ6 (ORCPT ); Mon, 4 Mar 2019 22:16:58 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Mar 2019 19:16:58 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,442,1544515200"; d="scan'208";a="159763741" Received: from local-michael-cet-test.sh.intel.com (HELO localhost) ([10.239.159.128]) by orsmga001.jf.intel.com with ESMTP; 04 Mar 2019 19:16:56 -0800 Date: Mon, 4 Mar 2019 18:11:26 +0800 From: Yang Weijiang To: Sean Christopherson Cc: pbonzini@redhat.com, rkrcmar@redhat.com, jmattson@google.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, mst@redhat.com, yu-cheng.yu@intel.com, Zhang Yi Z , weijiang.yang@intel.com Subject: Re: [PATCH v3 3/8] KVM:CPUID: Add CPUID support for Guest CET Message-ID: <20190304101126.GA3700@local-michael-cet-test.sh.intel.com> References: <20190225132716.6982-1-weijiang.yang@intel.com> <20190225132716.6982-4-weijiang.yang@intel.com> <20190304184753.GD17120@linux.intel.com> <20190304185429.GF17120@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190304185429.GF17120@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 04, 2019 at 10:54:29AM -0800, Sean Christopherson wrote: > On Mon, Mar 04, 2019 at 10:47:53AM -0800, Sean Christopherson wrote: > > On Mon, Feb 25, 2019 at 09:27:11PM +0800, Yang Weijiang wrote: > > > Guest CET SHSTK and IBT capability are reported via > > > CPUID.(EAX=7, ECX=0):ECX[bit 7] and EDX[bit 20] respectively. > > > Guest user mode and supervisor mode xsaves component size > > > is reported via CPUID.(EAX=0xD, ECX=1):ECX[bit 11] and ECX[bit 12] > > > respectively. > > > > > > Signed-off-by: Zhang Yi Z > > > Signed-off-by: Yang Weijiang > > > --- > > > arch/x86/kvm/cpuid.c | 60 +++++++++++++++++++++++++++++++++----------- > > > arch/x86/kvm/x86.h | 4 +++ > > > 2 files changed, 50 insertions(+), 14 deletions(-) > > > > > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > > > index cb1aece25b17..5e05756cc6db 100644 > > > --- a/arch/x86/kvm/cpuid.c > > > +++ b/arch/x86/kvm/cpuid.c > > > @@ -65,6 +65,16 @@ u64 kvm_supported_xcr0(void) > > > return xcr0; > > > } > > > > > > +u64 kvm_supported_xss(void) > > > +{ > > > + u64 xss; > > > + > > > + rdmsrl(MSR_IA32_XSS, xss); > > > > Honest question as I haven't thought through the flows: do we actually > > need to restrict XSS based on what's enabled in the host? This > > conflicts with your other statements that CET features can be enabled > > independent of host support. > > Never mind, just saw Paolo's comment in a previous version about XSAVE > being dependent on host XSS. The below comment about caching still > applies though. > In my WIP work, I use existing host_xss in vmx.c instead of reading MSR here to incoperate host status. > > And if we do incorporate the host status, the value should be read once > > and cached unless we're expecting the host value to change dynamically, > > e.g. see host_efer. > > > > > + xss &= KVM_SUPPORTED_XSS; > > > + return xss; > > > +} > > > +EXPORT_SYMBOL(kvm_supported_xss); > > > + > > > #define F(x) bit(X86_FEATURE_##x) > > > > > > /* For scattered features from cpufeatures.h; we currently expose none */