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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
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 <135ee490-a5a6-46c9-208e-81849b20d6b6@huawei.com>
From:   Jia He <hejianet@gmail.com>
Organization: ARM
Message-ID: <7898e483-a8e4-39a2-358f-8fcf838c242f@gmail.com>
Date:   Thu, 4 Jul 2019 14:04:34 +0800
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Hi Xiongfeng

Sorry, I missed your latter mail, you used a emulated SCI interrupt

---
Cheers,
Justin (Jia He)

On 2019/7/4 11:26, Xiongfeng Wang wrote:
> 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(-)
>>>
>> .
>>
--