Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH RFC 0/3] Support CPU hotplug for ARM64
To:     Xiongfeng Wang <wangxiongfeng2@huawei.com>, rjw@rjwysocki.net,
        catalin.marinas@arm.com, james.morse@arm.com
Cc:     linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, guohanjun@huawei.com,
        xiexiuqi@huawei.com, huawei.libin@huawei.com,
        john.garry@huawei.com, jonathan.cameron@huawei.com
References: <1561720392-45907-1-git-send-email-wangxiongfeng2@huawei.com>
From:   Jia He <hejianet@gmail.com>
Organization: ARM
Message-ID: <2b22cf4d-9646-9f20-41ae-cceb83d9791b@gmail.com>
Date:   Thu, 4 Jul 2019 11:00:13 +0800
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101
 Thunderbird/60.7.2
MIME-Version: 1.0
In-Reply-To: <1561720392-45907-1-git-send-email-wangxiongfeng2@huawei.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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?

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(-)
>