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 0483EC43462 for ; Fri, 2 Apr 2021 19:08:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AE02461181 for ; Fri, 2 Apr 2021 19:08:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236384AbhDBTIj (ORCPT ); Fri, 2 Apr 2021 15:08:39 -0400 Received: from mga06.intel.com ([134.134.136.31]:2092 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236301AbhDBTIi (ORCPT ); Fri, 2 Apr 2021 15:08:38 -0400 IronPort-SDR: 6V3AHgnvbbHADYhtMZ6NOE6Fs4NFcSZmbUHFTsgxueruuFBHtldxrLBttNnUoYUiDLZ5HrHGrU rsD59j7DJJ+g== X-IronPort-AV: E=McAfee;i="6000,8403,9942"; a="253854155" X-IronPort-AV: E=Sophos;i="5.81,300,1610438400"; d="scan'208";a="253854155" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Apr 2021 12:08:36 -0700 IronPort-SDR: QsxsuFpcnsvuimRxOw4HUitLjgOv8nzSOTJwS8XCg3d0mdhA/nj8aeEDhQzNpWTfaa4s/MJBAS pGXf9Qhuyg7w== X-IronPort-AV: E=Sophos;i="5.81,300,1610438400"; d="scan'208";a="446910313" Received: from hvijayak-mobl1.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.252.132.133]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Apr 2021 12:08:26 -0700 Date: Sat, 3 Apr 2021 08:08:24 +1300 From: Kai Huang To: Sean Christopherson Cc: Borislav Petkov , kvm@vger.kernel.org, linux-sgx@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, 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 Subject: Re: [PATCH v3 07/25] x86/sgx: Initialize virtual EPC driver even when SGX driver is disabled Message-Id: <20210403080824.d8bdb4c8f3c826c934acc53d@intel.com> In-Reply-To: References: <20210402094816.GC28499@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, 2 Apr 2021 15:42:51 +0000 Sean Christopherson wrote: > On Fri, Apr 02, 2021, Borislav Petkov wrote: > > On Fri, Mar 19, 2021 at 08:23:02PM +1300, Kai Huang wrote: > > > Modify sgx_init() to always try to initialize the virtual EPC driver, > > > even if the SGX driver is disabled. The SGX driver might be disabled > > > if SGX Launch Control is in locked mode, or not supported in the > > > hardware at all. This allows (non-Linux) guests that support non-LC > > > configurations to use SGX. > > > > > > Acked-by: Dave Hansen > > > Reviewed-by: Sean Christopherson > > > Signed-off-by: Kai Huang > > > --- > > > arch/x86/kernel/cpu/sgx/main.c | 10 +++++++++- > > > 1 file changed, 9 insertions(+), 1 deletion(-) > > > > > > diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c > > > index 6a734f484aa7..b73114150ff8 100644 > > > --- a/arch/x86/kernel/cpu/sgx/main.c > > > +++ b/arch/x86/kernel/cpu/sgx/main.c > > > @@ -743,7 +743,15 @@ static int __init sgx_init(void) > > > goto err_page_cache; > > > } > > > > > > - ret = sgx_drv_init(); > > > + /* > > > + * Always try to initialize the native *and* KVM drivers. > > > + * The KVM driver is less picky than the native one and > > > + * can function if the native one is not supported on the > > > + * current system or fails to initialize. > > > + * > > > + * Error out only if both fail to initialize. > > > + */ > > > + ret = !!sgx_drv_init() & !!sgx_vepc_init(); > > > > This is a silly way of writing: > > > > if (sgx_drv_init() && sgx_vepc_init()) > > goto err_kthread; > > > > methinks. > > Nope! That's wrong, as sgx_epc_init() will not be called if sgx_drv_init() > succeeds. And writing it as "if (sgx_drv_init() || sgx_vepc_init())" is also > wrong since that would kill SGX when one of the drivers is alive and well. Right. Thanks for pointing out.