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=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,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 AA261C433E0 for ; Tue, 9 Feb 2021 01:25:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5DEBD64DF6 for ; Tue, 9 Feb 2021 01:25:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230174AbhBIBZC (ORCPT ); Mon, 8 Feb 2021 20:25:02 -0500 Received: from mga03.intel.com ([134.134.136.65]:13938 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229854AbhBIBYz (ORCPT ); Mon, 8 Feb 2021 20:24:55 -0500 IronPort-SDR: D4zFAxwnk1X3dydwdAptcbSuRiwfDqxu59JEjPRcqSPGHuz5QfS3pMNTn33H8EehPkp8BZEgCl u8EQJRQrYZzw== X-IronPort-AV: E=McAfee;i="6000,8403,9889"; a="181875281" X-IronPort-AV: E=Sophos;i="5.81,163,1610438400"; d="scan'208";a="181875281" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Feb 2021 17:24:14 -0800 IronPort-SDR: Je3cvQ9ZoFLq4CMuUUNj6fBeq4wwv61EmGO3g7kMzGSLVRCAJNsRTzRoZbEIdt2cu3QTIQS/a6 NIbmJNVFRSIQ== X-IronPort-AV: E=Sophos;i="5.81,163,1610438400"; d="scan'208";a="395838752" Received: from shuo-intel.sh.intel.com (HELO localhost) ([10.239.154.30]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Feb 2021 17:24:10 -0800 Date: Tue, 9 Feb 2021 09:24:07 +0800 From: Shuo A Liu To: Randy Dunlap Cc: linux-kernel@vger.kernel.org, x86@kernel.org, Greg Kroah-Hartman , "H . Peter Anvin" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Yu Wang , Reinette Chatre , Zhi Wang , Borislav Petkov , Dave Hansen , Sen Christopherson , Dan Williams , Fengwei Yin , Zhenyu Wang Subject: Re: [PATCH v9 01/18] docs: acrn: Introduce ACRN Message-ID: <20210209012407.GC15601@shuo-intel.sh.intel.com> References: <20210207031040.49576-1-shuo.a.liu@intel.com> <20210207031040.49576-2-shuo.a.liu@intel.com> <6ae2679c-e172-a955-9df5-2b54b79dd854@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <6ae2679c-e172-a955-9df5-2b54b79dd854@infradead.org> User-Agent: Mutt/1.8.3 (2017-05-23) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Randy, On Mon 8.Feb'21 at 11:48:07 -0800, Randy Dunlap wrote: >On 2/6/21 7:10 PM, shuo.a.liu@intel.com wrote: >> From: Shuo Liu >> >> Add documentation on the following aspects of ACRN: >> >> 1) A brief introduction on the architecture of ACRN. >> 2) I/O request handling in ACRN. >> 3) CPUID functions of ACRN. > >> --- > >> diff --git a/Documentation/virt/acrn/io-request.rst b/Documentation/virt/acrn/io-request.rst >> new file mode 100644 >> index 000000000000..6cc3ea0fa1f5 >> --- /dev/null >> +++ b/Documentation/virt/acrn/io-request.rst >> @@ -0,0 +1,97 @@ >> +.. SPDX-License-Identifier: GPL-2.0 >> + >> +I/O request handling >> +==================== >> + >... >> + >> +1. I/O request >> +-------------- >> + >> +For each User VM, there is a shared 4-KByte memory region used for I/O requests >> +communication between the hypervisor and Service VM. An I/O request is a >> +256-byte structure buffer, which is 'struct acrn_io_request', that is filled by >> +an I/O handler of the hypervisor when a trapped I/O access happens in a User >> +VM. ACRN userspace in the Service VM first allocates a 4-KByte page and passes >> +the GPA (Guest Physical Address) of the buffer to the hypervisor. The buffer is >> +used as an array of 16 I/O request slots with each I/O request slot being 256 >> +bytes. This array is indexed by vCPU ID. > >Does this mean that ACRN has a limit of 16 vCPUs ? Yes. Now it is a limitation. Thanks shuo