From patchwork Fri Sep 9 08:08:53 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kai Huang X-Patchwork-Id: 12971213 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4400CECAAD3 for ; Fri, 9 Sep 2022 08:09:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229566AbiIIIJF (ORCPT ); Fri, 9 Sep 2022 04:09:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41360 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229862AbiIIIJF (ORCPT ); Fri, 9 Sep 2022 04:09:05 -0400 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 158F3D6B9D; Fri, 9 Sep 2022 01:09:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1662710944; x=1694246944; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=pHcMr/HNr8GqXxikW+gg67wqAAdhnAbWd7qTUYLTQA0=; b=hWI+SDRipT9KS06Qz5SReoxHfX8cAJlpA1rMYfrqdvCERDAh59yeaZDJ wJ42lWr/AAP+1qvesv2Z58PewJWin6rHS8SUYYUHqR6vghhbDrtBqnICP eSTkLYhkCnCSjNAK7gLfB3kE6CLymI+jKW/502WCdKVBATY5luSVrYWQ4 cOvn+H9y3A0AWlO8nZCi0m2IYwmfv0U90m35qPu1nYLTDr4BT01yRid85 R1/lhm5E4Cb0MeWUO9UHq8cH43z0EgvSeXdNblPPp6JoMhfwahIlKJodi PGPPqSGrDr3CyJUjWhr07EWXj7mz4lGIBF2zcJtY+T3y0l90hI/ErTy5g A==; X-IronPort-AV: E=McAfee;i="6500,9779,10464"; a="298762966" X-IronPort-AV: E=Sophos;i="5.93,302,1654585200"; d="scan'208";a="298762966" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Sep 2022 01:09:03 -0700 X-IronPort-AV: E=Sophos;i="5.93,302,1654585200"; d="scan'208";a="740976284" Received: from lmongeax-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.212.106.181]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Sep 2022 01:09:02 -0700 From: Kai Huang To: linux-sgx@vger.kernel.org Cc: dave.hansen@linux.intel.com, seanjc@google.com, jarkko@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] x86/intel: Clear SGX bit if both SGX driver and KVM SGX are not enabled Date: Fri, 9 Sep 2022 20:08:53 +1200 Message-Id: <20220909080853.547058-1-kai.huang@intel.com> X-Mailer: git-send-email 2.37.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org Currently on platform which has SGX enabled, if CONFIG_X86_SGX is not enabled, the X86_FEATURE_SGX is not cleared, resulting in /proc/cpuinfo shows "sgx" feature. This is not desired. Clear SGX feature bit if both SGX driver and KVM SGX are not enabled in init_ia32_feat_ctl(). Signed-off-by: Kai Huang --- Hi Dave, Sean, Jarkko, Could you help to review? Tested on SGX (BIOS) enabled machine with CONFIG_X86_SGX unset. This patch is generated on latest tip/master, but it applies to tip/x86/sgx cleanly as well. --- arch/x86/kernel/cpu/feat_ctl.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) base-commit: b8b09110cf290fdab4006b717da7a776ffb0cb73 diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c index 993697e71854..2f67409f5f00 100644 --- a/arch/x86/kernel/cpu/feat_ctl.c +++ b/arch/x86/kernel/cpu/feat_ctl.c @@ -191,6 +191,19 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c) return; } + /* + * By reaching here, it is certain that: + * - CPU supports SGX. + * - SGX is enabled by BIOS. + * + * However if both SGX driver and KVM SGX are not enabled, just + * need to clear SGX feature bit. + */ + if (!enable_sgx_driver && !enable_sgx_kvm) { + clear_cpu_cap(c, X86_FEATURE_SGX); + return; + } + /* * VMX feature bit may be cleared due to being disabled in BIOS, * in which case SGX virtualization cannot be supported either.