Re: [edk2-devel] [PATCH v4 0/9] support CPU hot-unplug

["Ankur Arora" <ankur.a.arora@oracle.com>]

On 2021-01-18 9:09 a.m., Laszlo Ersek wrote:
> On 01/18/21 07:34, Ankur Arora wrote:
>> Hi,
>>
>> This series adds support for CPU hot-unplug with OVMF.
>>
>> Please see this in conjunction with the QEMU secureboot hot-unplug v2
>> series posted here (now upstreamed):
>>    https://lore.kernel.org/qemu-devel/20201207140739.3829993-1-imammedo@redhat.com/
>>
>> Patches 1 and 3,
>>    ("OvmfPkg/CpuHotplugSmm: refactor hotplug logic")
>>    ("OvmfPkg/CpuHotplugSmm: add Qemu Cpu Status helper")
>> are either refactors or add support functions.
>>
>>    OvmfPkg/CpuHotplugSmm: introduce UnplugCpus()
>>    OvmfPkg/CpuHotplugSmm: add CpuEject()
>>    OvmfPkg/CpuHotplugSmm: add worker to do CPU ejection
>>
>> Patch 2 and 9,
>>    ("OvmfPkg/CpuHotplugSmm: collect hot-unplug events")
>>    ("OvmfPkg/SmmControl2Dxe: negotiate CPU hot-unplug")
>> handle the QEMU protocol logic for collection of CPU hot-unplug events
>> or the protocol negotiation.
>>
>> Patch 4,
>>    ("OvmfPkg/CpuHotplugSmm: introduce UnplugCpus()")
>> adds the MMI logic for CPU hot-unplug handling and informing
>> the PiSmmCpuDxeSmm of CPU removal.
>>
>> Patches 5 and 6,
>>    ("OvmfPkg/CpuHotplugSmm: define CPU_HOT_EJECT_DATA")
>>    ("OvmfPkg/SmmCpuFeaturesLib: init CPU ejection state")
>> sets up state for doing the CPU ejection as part of hot-unplug.
>>
>> Patches 7, and 8,
>>    ("OvmfPkg/CpuHotplugSmm: introduce UnplugCpus()")
>>    ("OvmfPkg/CpuHotplugSmm: add worker to do CPU ejection")
>> add the CPU ejection logic.
>>
>> Testing (with QEMU 5.2.50):
>>   - Stable with randomized CPU plug/unplug (guest maxcpus=1,8,128)
>>   - Synthetic tests with simultaneous multi CPU hot-unplug
>>   - Negotiation with/without CPU hotplug enabled
>>
>> Also at:
>>    github.com/terminus/edk2/ hot-unplug-v4
>>
>> Changelog:
>> v4:
>>    - Gets rid of unnecessary UefiCpuPkg changes
>>
>> v3:
>>    - Use a saner PCD based interface to share state between PiSmmCpuDxeSmm
>>      and OvmfPkg/CpuHotplugSmm
>>    - Cleaner split of the hot-unplug code
>>    URL: https://patchew.org/EDK2/20210115074533.277448-1-ankur.a.arora@oracle.com/
>>
>> v2:
>>    - Do the ejection via SmmCpuFeaturesRendezvousExit()
>>    URL: https://patchew.org/EDK2/20210107195515.106158-1-ankur.a.arora@oracle.com/
>>
>> RFC:
>>    URL: https://patchew.org/EDK2/20201208053432.2690694-1-ankur.a.arora@oracle.com/
>>
>>
>> Please review.
> 
> I've got this series in my review queue (confirming).
> 
> I'd like to finish review on the
> <https://bugzilla.tianocore.org/show_bug.cgi?id=3059> series first,
> since that's what I've got mostly in my mind at this point.
> 
> I hope to start reviewing the unplug series in a few days.

Sounds good. Thanks.

Ankur

> 
> Thanks
> Laszlo
> 
>>
>> Thanks
>> Ankur
>>
>> Ankur Arora (9):
>>    OvmfPkg/CpuHotplugSmm: refactor hotplug logic
>>    OvmfPkg/CpuHotplugSmm: collect hot-unplug events
>>    OvmfPkg/CpuHotplugSmm: add Qemu Cpu Status helper
>>    OvmfPkg/CpuHotplugSmm: introduce UnplugCpus()
>>    OvmfPkg/CpuHotplugSmm: define CPU_HOT_EJECT_DATA
>>    OvmfPkg/SmmCpuFeaturesLib: init CPU ejection state
>>    OvmfPkg/CpuHotplugSmm: add CpuEject()
>>    OvmfPkg/CpuHotplugSmm: add worker to do CPU ejection
>>    OvmfPkg/SmmControl2Dxe: negotiate CPU hot-unplug
>>
>>   OvmfPkg/CpuHotplugSmm/CpuHotplug.c                 | 435 ++++++++++++++++-----
>>   OvmfPkg/CpuHotplugSmm/CpuHotplugSmm.inf            |   1 +
>>   OvmfPkg/CpuHotplugSmm/QemuCpuhp.c                  |  58 ++-
>>   OvmfPkg/CpuHotplugSmm/QemuCpuhp.h                  |   6 +
>>   OvmfPkg/Include/IndustryStandard/QemuCpuHotplug.h  |   2 +
>>   OvmfPkg/Include/Library/CpuHotEjectData.h          |  31 ++
>>   .../Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.c  |  62 +++
>>   .../SmmCpuFeaturesLib/SmmCpuFeaturesLib.inf        |   3 +
>>   OvmfPkg/OvmfPkg.dec                                |   6 +
>>   OvmfPkg/SmmControl2Dxe/SmiFeatures.c               |  25 +-
>>   10 files changed, 527 insertions(+), 102 deletions(-)
>>   create mode 100644 OvmfPkg/Include/Library/CpuHotEjectData.h
>>
>