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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 03D06C433F5 for ; Fri, 31 Aug 2018 11:13:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AE0D420658 for ; Fri, 31 Aug 2018 11:13:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AE0D420658 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727978AbeHaPUj (ORCPT ); Fri, 31 Aug 2018 11:20:39 -0400 Received: from mga05.intel.com ([192.55.52.43]:18597 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726990AbeHaPUj (ORCPT ); Fri, 31 Aug 2018 11:20:39 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 31 Aug 2018 04:13:40 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,311,1531810800"; d="scan'208";a="84964652" Received: from ssirohi-mobl1.ger.corp.intel.com (HELO localhost) ([10.252.48.112]) by fmsmga004.fm.intel.com with ESMTP; 31 Aug 2018 04:13:35 -0700 Date: Fri, 31 Aug 2018 14:13:34 +0300 From: Jarkko Sakkinen To: Sean Christopherson Cc: Dave Hansen , x86@kernel.org, platform-driver-x86@vger.kernel.org, nhorman@redhat.com, npmccallum@redhat.com, linux-sgx@vger.kernel.org, Serge Ayoun , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Suresh Siddha , "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" Subject: Re: [PATCH v13 07/13] x86/sgx: Add data structures for tracking the EPC pages Message-ID: <20180831111334.GB16827@linux.intel.com> References: <20180827185507.17087-1-jarkko.sakkinen@linux.intel.com> <20180827185507.17087-8-jarkko.sakkinen@linux.intel.com> <4666cae8-c711-8dd5-cbce-3d97cc19a9e5@intel.com> <20180828103040.GA21326@linux.intel.com> <68d730bc-898c-973f-9506-648fd8a7c610@intel.com> <20180828213432.GB29488@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180828213432.GB29488@linux.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 28, 2018 at 02:34:32PM -0700, Sean Christopherson wrote: > On Tue, Aug 28, 2018 at 09:53:11AM -0700, Dave Hansen wrote: > > >>> + sgx_nr_epc_banks++; > > >>> + } > > >>> + > > >>> + if (!sgx_nr_epc_banks) { > > >>> + pr_err("There are zero EPC banks.\n"); > > >>> + return -ENODEV; > > >>> + } > > >>> + > > >>> + return 0; > > >>> +} > > >> > > >> Does this support hot-addition of a bank? If not, why not? > > ... > > > I'm not aware that we would have an ACPI specification for SGX so this > > > is all I have at the moment (does not show any ACPI event for > > > hotplugging). > > > > So you're saying the one platform you looked at don't support hotplug. > > I was looking for a more broad statement about SGX. > > Hardware doesn't support hotplug of EPC as the EPC size and location > is locked during activation of SGX. And IIRC, activation of SGX must > be synchronized across all CPUs in a multi-socket platform, e.g. you > can't late-enable SGX on a socket and due hotplugging that way. Makes me wonder how on a multisocket platform would this work anyway given that they have different fused keys? > In a virtualized environment there are no such restrictions. I am not > aware of any explicit requirements or use cases for supporting hotplug > of EPC, but that's probably only because virtualization of SGX is > fairly nascent. /Jarkko From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga05.intel.com ([192.55.52.43]:18597 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726990AbeHaPUj (ORCPT ); Fri, 31 Aug 2018 11:20:39 -0400 Date: Fri, 31 Aug 2018 14:13:34 +0300 From: Jarkko Sakkinen To: Sean Christopherson CC: Dave Hansen , , , , , , Serge Ayoun , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Suresh Siddha , "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" Subject: Re: [PATCH v13 07/13] x86/sgx: Add data structures for tracking the EPC pages Message-ID: <20180831111334.GB16827@linux.intel.com> References: <20180827185507.17087-1-jarkko.sakkinen@linux.intel.com> <20180827185507.17087-8-jarkko.sakkinen@linux.intel.com> <4666cae8-c711-8dd5-cbce-3d97cc19a9e5@intel.com> <20180828103040.GA21326@linux.intel.com> <68d730bc-898c-973f-9506-648fd8a7c610@intel.com> <20180828213432.GB29488@linux.intel.com> Content-Type: text/plain; charset="us-ascii" In-Reply-To: <20180828213432.GB29488@linux.intel.com> Sender: List-ID: Return-Path: linux-sgx-owner@vger.kernel.org MIME-Version: 1.0 On Tue, Aug 28, 2018 at 02:34:32PM -0700, Sean Christopherson wrote: > On Tue, Aug 28, 2018 at 09:53:11AM -0700, Dave Hansen wrote: > > >>> + sgx_nr_epc_banks++; > > >>> + } > > >>> + > > >>> + if (!sgx_nr_epc_banks) { > > >>> + pr_err("There are zero EPC banks.\n"); > > >>> + return -ENODEV; > > >>> + } > > >>> + > > >>> + return 0; > > >>> +} > > >> > > >> Does this support hot-addition of a bank? If not, why not? > > ... > > > I'm not aware that we would have an ACPI specification for SGX so this > > > is all I have at the moment (does not show any ACPI event for > > > hotplugging). > > > > So you're saying the one platform you looked at don't support hotplug. > > I was looking for a more broad statement about SGX. > > Hardware doesn't support hotplug of EPC as the EPC size and location > is locked during activation of SGX. And IIRC, activation of SGX must > be synchronized across all CPUs in a multi-socket platform, e.g. you > can't late-enable SGX on a socket and due hotplugging that way. Makes me wonder how on a multisocket platform would this work anyway given that they have different fused keys? > In a virtualized environment there are no such restrictions. I am not > aware of any explicit requirements or use cases for supporting hotplug > of EPC, but that's probably only because virtualization of SGX is > fairly nascent. /Jarkko From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarkko Sakkinen Subject: Re: [PATCH v13 07/13] x86/sgx: Add data structures for tracking the EPC pages Date: Fri, 31 Aug 2018 14:13:34 +0300 Message-ID: <20180831111334.GB16827@linux.intel.com> References: <20180827185507.17087-1-jarkko.sakkinen@linux.intel.com> <20180827185507.17087-8-jarkko.sakkinen@linux.intel.com> <4666cae8-c711-8dd5-cbce-3d97cc19a9e5@intel.com> <20180828103040.GA21326@linux.intel.com> <68d730bc-898c-973f-9506-648fd8a7c610@intel.com> <20180828213432.GB29488@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20180828213432.GB29488@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Sean Christopherson Cc: Dave Hansen , x86@kernel.org, platform-driver-x86@vger.kernel.org, nhorman@redhat.com, npmccallum@redhat.com, linux-sgx@vger.kernel.org, Serge Ayoun , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Suresh Siddha , "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" List-Id: platform-driver-x86.vger.kernel.org On Tue, Aug 28, 2018 at 02:34:32PM -0700, Sean Christopherson wrote: > On Tue, Aug 28, 2018 at 09:53:11AM -0700, Dave Hansen wrote: > > >>> + sgx_nr_epc_banks++; > > >>> + } > > >>> + > > >>> + if (!sgx_nr_epc_banks) { > > >>> + pr_err("There are zero EPC banks.\n"); > > >>> + return -ENODEV; > > >>> + } > > >>> + > > >>> + return 0; > > >>> +} > > >> > > >> Does this support hot-addition of a bank? If not, why not? > > ... > > > I'm not aware that we would have an ACPI specification for SGX so this > > > is all I have at the moment (does not show any ACPI event for > > > hotplugging). > > > > So you're saying the one platform you looked at don't support hotplug. > > I was looking for a more broad statement about SGX. > > Hardware doesn't support hotplug of EPC as the EPC size and location > is locked during activation of SGX. And IIRC, activation of SGX must > be synchronized across all CPUs in a multi-socket platform, e.g. you > can't late-enable SGX on a socket and due hotplugging that way. Makes me wonder how on a multisocket platform would this work anyway given that they have different fused keys? > In a virtualized environment there are no such restrictions. I am not > aware of any explicit requirements or use cases for supporting hotplug > of EPC, but that's probably only because virtualization of SGX is > fairly nascent. /Jarkko