Re: [PATCH RFC 0/3] Support CPU hotplug for ARM64

From: Jia He
Date: Thu Jul 04 2019 - 02:04:57 EST


Hi Xiongfeng

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

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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

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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):
ÂÂ ACPI / scan: evaluate _STA for processors declared via ASL Device
ÂÂÂÂ statement
ÂÂ arm64: mark all the GICC nodes in MADT as possible cpu
ÂÂ 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(-)

.

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