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_CR_TRAILER,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 F39BEC433DB for ; Tue, 16 Feb 2021 18:39:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D0F7C64E2B for ; Tue, 16 Feb 2021 18:39:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229572AbhBPSj1 (ORCPT ); Tue, 16 Feb 2021 13:39:27 -0500 Received: from mga02.intel.com ([134.134.136.20]:48766 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230362AbhBPSj0 (ORCPT ); Tue, 16 Feb 2021 13:39:26 -0500 IronPort-SDR: Qqp10DiXQ9fFzuBLmO4W7trAbVXZmHjwLgqmTHfBvWP+dIN96S9bHZ72wHC5TcD0Y2jdxn9agL ucUFPIbSALVQ== X-IronPort-AV: E=McAfee;i="6000,8403,9897"; a="170113484" X-IronPort-AV: E=Sophos;i="5.81,184,1610438400"; d="scan'208";a="170113484" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Feb 2021 10:38:44 -0800 IronPort-SDR: ZcKwjlU3ZwM2jn/gFh8ZKugK6sChsdR8YrJ7jEjkEelq+kUVgF5K90vXW40gLcOnOtPxQ19kCW ZWK8+/UkwYvQ== X-IronPort-AV: E=Sophos;i="5.81,184,1610438400"; d="scan'208";a="589332575" Received: from twblanch-mobl.amr.corp.intel.com (HELO [10.209.156.22]) ([10.209.156.22]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Feb 2021 10:38:43 -0800 Subject: Re: [RFC PATCH v5 05/26] x86/sgx: Introduce virtual EPC for use by KVM guests 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, rick.p.edgecombe@intel.com, haitao.huang@intel.com, pbonzini@redhat.com, bp@alien8.de, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com References: <4813545fa5765d05c2ed18f2e2c44275bd087c0a.1613221549.git.kai.huang@intel.com> 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: <4813545fa5765d05c2ed18f2e2c44275bd087c0a.1613221549.git.kai.huang@intel.com> 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 2/13/21 5:28 AM, Kai Huang wrote: > SGX driver uses misc device /dev/sgx_enclave to support userspace to > create enclave. Each file descriptor from opening /dev/sgx_enclave > represents an enclave. Is this strictly true? Does dup(2) create a new enclave? > Unlike SGX driver, KVM doesn't control how guest > uses EPC, therefore EPC allocated to KVM guest is not associated to an > encalve, and /dev/sgx_enclave is not suitable for allocating EPC for KVM ^ enclave > guest. > Having separate device nodes for SGX driver and KVM virtual EPC also > allows separate permission control for running host SGX enclaves and > KVM SGX guests. Specifically, 'sgx_vepc' is a less restrictive interface. It would make a lot of sense to more tightly control access compared to 'sgx_enclave'. > More specifically, to allocate a virtual EPC instance with particular > size, the userspace hypervisor opens /dev/sgx_vepc, and uses mmap() > with the intended size to get an address range of virtual EPC. Then > it may use the address range to create one KVM memory slot as virtual > EPC for guest. This paragraph doesn't really explain anything important to me. Both devices require using mmap(). With typos in the changelog fixed, I'm OK with the rest: Acked-by: Dave Hansen BTW... A lot of this patch is just a skeletal device driver. I'm a horrible device driver writer, so take this ack as "everything seems explained well" versus "I promise this will pass muster with the guys who review device drivers all day long."