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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 66143C432C2 for ; Wed, 25 Sep 2019 17:28:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3EF002146E for ; Wed, 25 Sep 2019 17:28:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="OXnHUrqw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2634189AbfIYR2Q (ORCPT ); Wed, 25 Sep 2019 13:28:16 -0400 Received: from mail.skyhub.de ([5.9.137.197]:56926 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2634177AbfIYR2Q (ORCPT ); Wed, 25 Sep 2019 13:28:16 -0400 Received: from zn.tnic (p200300EC2F0BA100707709EB32B84CF4.dip0.t-ipconnect.de [IPv6:2003:ec:2f0b:a100:7077:9eb:32b8:4cf4]) (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 91A391EC0A91; Wed, 25 Sep 2019 19:28:14 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1569432494; 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=f5S/bY3WTvdMzJpiB20pTgPtyAu2kxkvYFmDAMgwzaQ=; b=OXnHUrqwhPc94OpC7hb7Ih+XlZTC8O1X9YXCL3iiaaTWVjahCMTuXwLTCQD9WEEYiuSv1y T0qSwax77qfeRqnxf96T45UU+s73MEKSn27J8EPXABqiIjDvqA+wsixtVo68bAOwkqIA7L r7SxswW0nQTUKsJKsFUXB/kZ1jHH+hQ= Date: Wed, 25 Sep 2019 19:28:15 +0200 From: Borislav Petkov To: Sean Christopherson Cc: Jarkko Sakkinen , linux-kernel@vger.kernel.org, x86@kernel.org, linux-sgx@vger.kernel.org, akpm@linux-foundation.org, dave.hansen@intel.com, nhorman@redhat.com, npmccallum@redhat.com, serge.ayoun@intel.com, shay.katz-zamir@intel.com, haitao.huang@intel.com, andriy.shevchenko@linux.intel.com, tglx@linutronix.de, kai.svahn@intel.com, josh@joshtriplett.org, luto@kernel.org, kai.huang@intel.com, rientjes@google.com, cedric.xing@intel.com, Kai Huang , Haim Cohen Subject: Re: [PATCH v22 02/24] x86/cpufeatures: x86/msr: Intel SGX Launch Control hardware bits Message-ID: <20190925172815.GG3891@zn.tnic> References: <20190903142655.21943-1-jarkko.sakkinen@linux.intel.com> <20190903142655.21943-3-jarkko.sakkinen@linux.intel.com> <20190924155232.GG19317@zn.tnic> <20190925140903.GA19638@linux.intel.com> <20190925151949.GE3891@zn.tnic> <20190925164932.GE31852@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190925164932.GE31852@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 Wed, Sep 25, 2019 at 09:49:32AM -0700, Sean Christopherson wrote: > Correct, only X86_FEATURE_SGX_LC is cleared. The idea is to have SGX_LC > reflect whether or not flexible launch control is fully enabled, no more > no less. So we do not disable SGX when the MSRs are read-only - we disable only launch control. > Functionally, this doesn't impact support for native enclaves as the > driver will refuse to load if SGX_LC=0. So why aren't we clearing all feature bits then? What's the purpose for leaving them set if we're not going to support hardcoded OEM vendor hash in the MSRs anyway? > Looking forward, this *will* affect KVM. As proposed, KVM would expose > SGX to a guest regardless of SGX_LC support. > > https://lkml.kernel.org/r/20190727055214.9282-17-sean.j.christopherson@intel.com ... which would do what exactly? Guests can execute SGX only when signed by the Intel key, when LC is disabled? -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette