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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 35EC5C433DB for ; Tue, 2 Mar 2021 19:50:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC02B60201 for ; Tue, 2 Mar 2021 19:50:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1581392AbhCBSvG (ORCPT ); Tue, 2 Mar 2021 13:51:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58136 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1449002AbhCBQDc (ORCPT ); Tue, 2 Mar 2021 11:03:32 -0500 Received: from mail-pg1-x52c.google.com (mail-pg1-x52c.google.com [IPv6:2607:f8b0:4864:20::52c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 11710C061788 for ; Tue, 2 Mar 2021 08:02:21 -0800 (PST) Received: by mail-pg1-x52c.google.com with SMTP id o10so14103287pgg.4 for ; Tue, 02 Mar 2021 08:02:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=svOHLaBnqkDfLhE0cZ4LJEE36nGBqyQ9USTfjmqqgrQ=; b=Lt+J5F4Qzn5XcdVTLUz5v5KhazZ3GtoSKi4eCwnhUyfDVP7CjIdTe7wrEupIgJjMIA HlEZVtJ4zbOe7b76HD6dAnG1S4mTkKoSoRXAJchNJGjm5jbrHl2vNE2e9zX2776arIOf UdKsWBRwTk9ywichOZb2Ro3wb2a2Z+VxipxSFch75SK8FHkGV246bAofC+niKQpJXehf 72HdOj0vU8M5ay2vJJwK40EHtP0D4bsWr/cHZQsOdFTq+DzNSkk9AJFiElG6TSAEPQtk W/sjo/MiPdD35E2LyD3d1O6fbxO62upDmumlXFe+R2chC97vx6mTl3qzaOix0UNu7QPy uqmA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=svOHLaBnqkDfLhE0cZ4LJEE36nGBqyQ9USTfjmqqgrQ=; b=j4mtmI5NjgGkHLj6Qp9EeHqw8xQRne3qAILppEJfdg8BtBWCgNt8A/iNo4ffCCnshV r1Ea9BLYYtEO/i006y7s7OwJjlF/tU6ezGxD/Y+2UWJ1cZubkTuslRKrm65ZBFC63e/a V4OeQkS210hOTQ57CHBjb5ZGBsr5M0zB/6n1+5hUb2DICiaTvTtq0q+EyJJL84Y+QGDs Zpq4puESFOkQ7mA/HUsChRewXkNe7+gUJWnBQbQmfNCn8QOt4CrPHNyMK1l0JYLUKiKY ndwlZqmiM5/PnncuwTxDXfKxFLTsmZw2fn7UAaD/Q5UPlQwHTcOTe92uo2vY/lCzTEie goYA== X-Gm-Message-State: AOAM533Wzq2LEKFP/jJJGHJBUANcKNC1JkE19s8EjN0OHj9Ln/qUOg67 aH8MlFzGDa4RfboUMD3SQy8QbA== X-Google-Smtp-Source: ABdhPJw8fIoq/1KmCJqNQp/hD/uLuk0oH7QC1JQ5gpW5sqU026irp8qx8M6uJ7zNiZLj0GP87RUJYw== X-Received: by 2002:a62:7d17:0:b029:1ee:3bbe:fa5f with SMTP id y23-20020a627d170000b02901ee3bbefa5fmr3727106pfc.67.1614700940422; Tue, 02 Mar 2021 08:02:20 -0800 (PST) Received: from google.com ([2620:15c:f:10:805d:6324:3372:6183]) by smtp.gmail.com with ESMTPSA id ie12sm3763220pjb.52.2021.03.02.08.02.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Mar 2021 08:02:19 -0800 (PST) Date: Tue, 2 Mar 2021 08:02:13 -0800 From: Sean Christopherson To: Kai Huang Cc: Borislav Petkov , kvm@vger.kernel.org, x86@kernel.org, linux-sgx@vger.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 02/25] x86/cpufeatures: Add SGX1 and SGX2 sub-features Message-ID: References: <20210301100037.GA6699@zn.tnic> <3fce1dd2abd42597bde7ae9496bde7b9596b2797.camel@intel.com> <20210301103043.GB6699@zn.tnic> <7603ef673997b6674f785d333a4f263c749d2cf3.camel@intel.com> <20210301105346.GC6699@zn.tnic> <20210301113257.GD6699@zn.tnic> <0adc41774945bf9d6e6a72a93b83c80aa8c59544.camel@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <0adc41774945bf9d6e6a72a93b83c80aa8c59544.camel@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 02, 2021, Kai Huang wrote: > On Mon, 2021-03-01 at 12:32 +0100, Borislav Petkov wrote: > > On Tue, Mar 02, 2021 at 12:28:27AM +1300, Kai Huang wrote: > > > I think some script can utilize /proc/cpuinfo. For instance, admin can have > > > automation tool/script to deploy enclave (with sgx2) apps, and that script can check > > > whether platform supports sgx2 or not, before it can deploy those enclave apps. Or > > > enclave author may just want to check /proc/cpuinfo to know whether the machine can > > > be used for testing sgx2 enclave or not. > > > > This doesn't sound like a concrete use of this. So you can hide it > > initially with "" until you guys have a use case. Exposing it later is > > always easy vs exposing it now and then not being able to change it > > anymore. > > > > Hi Haitao, Jarkko, > > Do you have more concrete use case of needing "sgx2" in /proc/cpuinfo? The KVM use case is to query /proc/cpuinfo to see if sgx2 can be enabled in a guest. The counter-argument to that is we might want sgx2 in /proc/cpuinfo to mean sgx2 is enabled in hardware _and_ supported by the kernel. Userspace can grep for sgx in /proc/cpuinfo, and use cpuid to discover sgx2, so it's not a blocker. That being said, adding some form of capability/versioning to SGX seems inevitable, not sure it's worth witholding sgx2 from /proc/cpuinfo.