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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 7DB7DC06511 for ; Thu, 4 Jul 2019 03:28:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 608872082E for ; Thu, 4 Jul 2019 03:28:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727279AbfGDD2Y (ORCPT ); Wed, 3 Jul 2019 23:28:24 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:40310 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726964AbfGDD2X (ORCPT ); Wed, 3 Jul 2019 23:28:23 -0400 Received: from DGGEMS407-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id F08F8AD5DDA7AD8D9FE7; Thu, 4 Jul 2019 11:28:20 +0800 (CST) Received: from [127.0.0.1] (10.184.52.56) by DGGEMS407-HUB.china.huawei.com (10.3.19.207) with Microsoft SMTP Server id 14.3.439.0; Thu, 4 Jul 2019 11:28:12 +0800 Subject: Re: [PATCH RFC 0/3] Support CPU hotplug for ARM64 To: Jia He , , , CC: , , , , , , , References: <1561720392-45907-1-git-send-email-wangxiongfeng2@huawei.com> <2b22cf4d-9646-9f20-41ae-cceb83d9791b@gmail.com> From: Xiongfeng Wang Message-ID: <135ee490-a5a6-46c9-208e-81849b20d6b6@huawei.com> Date: Thu, 4 Jul 2019 11:26:16 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <2b22cf4d-9646-9f20-41ae-cceb83d9791b@gmail.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.184.52.56] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Justin, On 2019/7/4 11:00, Jia He wrote: > Hi Xiongfeng > > It is a little bit awkful that I am also  investigating acpi based cpu hotplug issue silimar with > > your idea. My question is your purpose to implement the vcpu hotplug in arm64 qemu? Yes, my purpose is to implement the vcpu hotplug in arm64 qemu. So that I can add or remove vcpu without shutting down the Guest OS. Thanks, Xiongfeng > > Thanks for the ellaboration > > --- > Cheers, > Justin (Jia He) > > On 2019/6/28 19:13, Xiongfeng Wang wrote: >> This patchset mark all the GICC node in MADT as possible CPUs even though it >> is disabled. But only those enabled GICC node are marked as present CPUs. >> So that kernel will initialize some CPU related data structure in advance before >> the CPU is actually hot added into the system. This patchset also implement >> 'acpi_(un)map_cpu()' and 'arch_(un)register_cpu()' for ARM64. These functions are >> needed to enable CPU hotplug. >> >> To support CPU hotplug, we need to add all the possible GICC node in MADT >> including those CPUs that are not present but may be hot added later. Those >> CPUs are marked as disabled in GICC nodes. >> >> Xiongfeng Wang (3): >>    ACPI / scan: evaluate _STA for processors declared via ASL Device >>      statement >>    arm64: mark all the GICC nodes in MADT as possible cpu >>    arm64: Add CPU hotplug support >> >>   arch/arm64/kernel/acpi.c  | 22 ++++++++++++++++++++++ >>   arch/arm64/kernel/setup.c | 19 ++++++++++++++++++- >>   arch/arm64/kernel/smp.c   | 11 +++++------ >>   drivers/acpi/scan.c       | 12 ++++++++++++ >>   4 files changed, 57 insertions(+), 7 deletions(-) >> > > . >