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=-12.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, 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 DEAEEC433E0 for ; Mon, 8 Feb 2021 20:59:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 89E9B64E45 for ; Mon, 8 Feb 2021 20:59:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234122AbhBHU7d (ORCPT ); Mon, 8 Feb 2021 15:59:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55254 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236405AbhBHTtN (ORCPT ); Mon, 8 Feb 2021 14:49:13 -0500 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7C42CC061788 for ; Mon, 8 Feb 2021 11:48:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender :Reply-To:Content-ID:Content-Description; bh=YgFez7BF/vukNamJA5m6x4ZictvAntBpWelcO2BexDY=; b=D9PzXmIa5nMUPUhNvPdGSbUukc R6Q4y4nMWl8+TtQunUpqbYC9hoDgVv3b/rRMiNsGUeAWca60Ij2EuYmFJCIVCxtHTCdLjz4qRf1m4 PXjSBF2X7QBNpi9vJ9+bE4AD8daPaKPBOK0+mgfkYdxudDe+CzVh7k12mGdx2wNG2cUxq9JgYZ2wV 2KQaKeiyqNwt1x9RhsUPLjv++GK5aq24G3RDk3Zo4uS1NoIo4f4ecC9TB+JRlUqAb/z6Wn0eGAWQz TcDk9N+eejWZjMlZ5cnmW896GyFJJj9OP+uwQT+gcx6LE2JpILH9yQlm8clSfkfqJa83HTUZlsg5O 4yrZm7yg==; Received: from [2601:1c0:6280:3f0::cf3b] by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1l9CW6-0000St-6O; Mon, 08 Feb 2021 19:48:14 +0000 Subject: Re: [PATCH v9 01/18] docs: acrn: Introduce ACRN To: shuo.a.liu@intel.com, linux-kernel@vger.kernel.org, x86@kernel.org Cc: 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 References: <20210207031040.49576-1-shuo.a.liu@intel.com> <20210207031040.49576-2-shuo.a.liu@intel.com> From: Randy Dunlap Message-ID: <6ae2679c-e172-a955-9df5-2b54b79dd854@infradead.org> Date: Mon, 8 Feb 2021 11:48:07 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <20210207031040.49576-2-shuo.a.liu@intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi-- 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 ? thanks. -- ~Randy