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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 00D98C433E6 for ; Sun, 7 Mar 2021 23:51:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BA54164F52 for ; Sun, 7 Mar 2021 23:51:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233294AbhCGXvK (ORCPT ); Sun, 7 Mar 2021 18:51:10 -0500 Received: from mga17.intel.com ([192.55.52.151]:46866 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229797AbhCGXuc (ORCPT ); Sun, 7 Mar 2021 18:50:32 -0500 IronPort-SDR: pwSX+dk9L+fi22pZ5Ud10wAJHXGO11yuToTEKIshtu66U9YSrEsK69D73zoJZCEElbO99Y+cLP rwsuiua85T2g== X-IronPort-AV: E=McAfee;i="6000,8403,9916"; a="167846651" X-IronPort-AV: E=Sophos;i="5.81,231,1610438400"; d="scan'208";a="167846651" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Mar 2021 15:50:31 -0800 IronPort-SDR: uRqqECxC8vUIEdMu/4tTwt7PdBmi+zTwwUh+kXMtrh5JzasxrG9oq194U1/8XlViglmbBTVPAl Cu4NG00r6iuQ== X-IronPort-AV: E=Sophos;i="5.81,231,1610438400"; d="scan'208";a="409096469" Received: from ggkanher-mobl4.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.252.142.177]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Mar 2021 15:50:28 -0800 Date: Mon, 8 Mar 2021 12:50:26 +1300 From: Kai Huang To: Borislav Petkov Cc: kvm@vger.kernel.org, x86@kernel.org, linux-sgx@vger.kernel.org, linux-kernel@vger.kernel.org, seanjc@google.com, jarkko@kernel.org, luto@kernel.org, dave.hansen@intel.com, rick.p.edgecombe@intel.com, haitao.huang@intel.com, pbonzini@redhat.com, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, jethro@fortanix.com, b.thiel@posteo.de Subject: Re: [PATCH 06/25] x86/cpu/intel: Allow SGX virtualization without Launch Control support Message-Id: <20210308125026.08ece7c1f99406a14812715e@intel.com> In-Reply-To: <20210305172957.GE2685@zn.tnic> References: <12541888ae9ac7f517582aa64d9153feede7aed4.1614590788.git.kai.huang@intel.com> <20210305172957.GE2685@zn.tnic> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 5 Mar 2021 18:29:57 +0100 Borislav Petkov wrote: > On Mon, Mar 01, 2021 at 10:45:02PM +1300, Kai Huang wrote: > > From: Sean Christopherson > > > > The kernel will currently disable all SGX support if the hardware does > > not support launch control. Make it more permissive to allow SGX > > virtualization on systems without Launch Control support. This will > > allow KVM to expose SGX to guests that have less-strict requirements on > > the availability of flexible launch control. > > > > Improve error message to distinguish between three cases. There are two > > cases where SGX support is completely disabled: > > 1) SGX has been disabled completely by the BIOS > > 2) SGX LC is locked by the BIOS. Bare-metal support is disabled because > > of LC unavailability. SGX virtualization is unavailable (because of > > Kconfig). > > One where it is partially available: > > 3) SGX LC is locked by the BIOS. Bare-metal support is disabled because > > of LC unavailability. SGX virtualization is supported. > > > > Signed-off-by: Sean Christopherson > > Co-developed-by: Kai Huang > > Acked-by: Dave Hansen > > Signed-off-by: Kai Huang > > --- > > arch/x86/kernel/cpu/feat_ctl.c | 57 ++++++++++++++++++++++++++-------- > > 1 file changed, 44 insertions(+), 13 deletions(-) > > > > diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c > > index 27533a6e04fa..96c370284913 100644 > > --- a/arch/x86/kernel/cpu/feat_ctl.c > > +++ b/arch/x86/kernel/cpu/feat_ctl.c > > @@ -105,7 +105,8 @@ early_param("nosgx", nosgx); > > void init_ia32_feat_ctl(struct cpuinfo_x86 *c) > > { > > bool tboot = tboot_enabled(); > > - bool enable_sgx; > > + bool enable_sgx_any, enable_sgx_kvm, enable_sgx_driver; > > + bool enable_vmx; > > u64 msr; > > The preferred ordering of variable declarations at the beginning of a > function is reverse fir tree order:: > > struct long_struct_name *descriptive_name; > unsigned long foo, bar; > unsigned int tmp; > int ret; > Will do. Since as you suggested, enable_sgx_any will be removed, and initializing enable_sgx_driver/kvm will be moved into the if () statement, I think we should explicitly initialize them here. How about below? bool enable_sgx_kvm = enable_sgx_driver = false; bool tboot = tboot_enabled(); bool enable_vmx; ... > > > if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr)) { > > @@ -114,13 +115,21 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c) > > return; > > } > > > > + enable_vmx = cpu_has(c, X86_FEATURE_VMX) && > > + IS_ENABLED(CONFIG_KVM_INTEL); > > + > > /* > > - * Enable SGX if and only if the kernel supports SGX and Launch Control > > - * is supported, i.e. disable SGX if the LE hash MSRs can't be written. > > + * Separate out SGX driver enabling from KVM. This allows KVM > > + * guests to use SGX even if the kernel SGX driver refuses to > > + * use it. This happens if flexible Faunch Control is not > > + * available. > > */ > > - enable_sgx = cpu_has(c, X86_FEATURE_SGX) && > > - cpu_has(c, X86_FEATURE_SGX_LC) && > > - IS_ENABLED(CONFIG_X86_SGX); > > + enable_sgx_any = cpu_has(c, X86_FEATURE_SGX) && > > + IS_ENABLED(CONFIG_X86_SGX); > > + enable_sgx_driver = enable_sgx_any && > > + cpu_has(c, X86_FEATURE_SGX_LC); > > + enable_sgx_kvm = enable_sgx_any && enable_vmx && > > + IS_ENABLED(CONFIG_X86_SGX_KVM); > > That enable_sgx_any use looks weird. You can get rid of it: > > if (cpu_has(c, X86_FEATURE_SGX) && IS_ENABLED(CONFIG_X86_SGX)) { > enable_sgx_driver = cpu_has(c, X86_FEATURE_SGX_LC); > enable_sgx_kvm = enable_vmx && IS_ENABLED(CONFIG_X86_SGX_KVM); > } > > and yap, let longer lines stick out. Thanks. Will do. > > Thx. > > -- > Regards/Gruss, > Boris. > > https://people.kernel.org/tglx/notes-about-netiquette