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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,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 D5811C43381 for ; Fri, 5 Mar 2021 17:30:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A1BFE650AA for ; Fri, 5 Mar 2021 17:30:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229693AbhCERa0 (ORCPT ); Fri, 5 Mar 2021 12:30:26 -0500 Received: from mail.skyhub.de ([5.9.137.197]:50164 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229465AbhCERaG (ORCPT ); Fri, 5 Mar 2021 12:30:06 -0500 Received: from zn.tnic (p200300ec2f0b95001b26a1a345abd660.dip0.t-ipconnect.de [IPv6:2003:ec:2f0b:9500:1b26:a1a3:45ab:d660]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 46BFC1EC0528; Fri, 5 Mar 2021 18:30:04 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1614965404; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=L2DznrHs2974hAtcbJbvPMJYMDAjtrQkOfNloB/J18Q=; b=OwVefF93ifvJ8TJ6cAegoM4gB4nOErwB5WceW+2rX+dAgQUQoafLsfVikx7oeag4PwkqXE 7CNJI1j8b+qoF9/J4BaQmbdwUNvIL75wE6lfpJWn8rHt0Q8BTH7cY2Ib+FEybueqyX+poB 1X3SmYcjaOUtSK150JIasD4Fm+VA5YE= Date: Fri, 5 Mar 2021 18:29:57 +0100 From: Borislav Petkov To: Kai Huang 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: <20210305172957.GE2685@zn.tnic> References: <12541888ae9ac7f517582aa64d9153feede7aed4.1614590788.git.kai.huang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <12541888ae9ac7f517582aa64d9153feede7aed4.1614590788.git.kai.huang@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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; > 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. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette