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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 80EFAC433DB for ; Tue, 26 Jan 2021 15:58:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4E9712082D for ; Tue, 26 Jan 2021 15:58:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403768AbhAZPfR (ORCPT ); Tue, 26 Jan 2021 10:35:17 -0500 Received: from mga02.intel.com ([134.134.136.20]:17317 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392778AbhAZPfP (ORCPT ); Tue, 26 Jan 2021 10:35:15 -0500 IronPort-SDR: 7n3fh0Yo4kyIh9Zj3wB9hjPjhITLPHE7+xunB8phl61HDrY1SzMnSQmegpyy1eq2PVgWVCpo4j ACfYxDfWyNpA== X-IronPort-AV: E=McAfee;i="6000,8403,9876"; a="167018166" X-IronPort-AV: E=Sophos;i="5.79,375,1602572400"; d="scan'208";a="167018166" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jan 2021 07:34:35 -0800 IronPort-SDR: 5Y67a1lGtnM/GGlijPMYZ33ctSO2F5/dR1x05PVxDmwyj+tVtMiu98DHOtmpIOPN0/Rv4XPCVn +geS5Ew3kHJg== X-IronPort-AV: E=Sophos;i="5.79,375,1602572400"; d="scan'208";a="369137935" Received: from ekfraser-mobl1.amr.corp.intel.com (HELO [10.209.173.94]) ([10.209.173.94]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jan 2021 07:34:33 -0800 Subject: Re: [RFC PATCH v3 01/27] x86/cpufeatures: Add SGX1 and SGX2 sub-features To: Kai Huang , linux-sgx@vger.kernel.org, kvm@vger.kernel.org, x86@kernel.org Cc: seanjc@google.com, jarkko@kernel.org, luto@kernel.org, haitao.huang@intel.com, pbonzini@redhat.com, bp@alien8.de, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com References: From: Dave Hansen Autocrypt: addr=dave.hansen@intel.com; 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On 1/26/21 1:30 AM, Kai Huang wrote: > From: Sean Christopherson > > Add SGX1 and SGX2 feature flags, via CPUID.0x12.0x0.EAX, as scattered > features, since adding a new leaf for only two bits would be wasteful. > As part of virtualizing SGX, KVM will expose the SGX CPUID leafs to its > guest, and to do so correctly needs to query hardware and kernel support > for SGX1 and SGX2. It's also not _just_ exposing the CPUID leaves. There are some checks here when KVM is emulating some SGX instructions too, right? > diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h > index 84b887825f12..18b2d0c8bbbe 100644 > --- a/arch/x86/include/asm/cpufeatures.h > +++ b/arch/x86/include/asm/cpufeatures.h > @@ -292,6 +292,8 @@ > #define X86_FEATURE_FENCE_SWAPGS_KERNEL (11*32+ 5) /* "" LFENCE in kernel entry SWAPGS path */ > #define X86_FEATURE_SPLIT_LOCK_DETECT (11*32+ 6) /* #AC for split lock */ > #define X86_FEATURE_PER_THREAD_MBA (11*32+ 7) /* "" Per-thread Memory Bandwidth Allocation */ > +#define X86_FEATURE_SGX1 (11*32+ 8) /* Software Guard Extensions sub-feature SGX1 */ > +#define X86_FEATURE_SGX2 (11*32+ 9) /* Software Guard Extensions sub-feature SGX2 */ FWIW, I'm not sure how valuable it is to spell the SGX acronym out three times. Can't we use those bytes to put something more useful in that comment?