Re: [edk2-devel] [PATCH v7 00/10] support CPU hot-unplug

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

On 2021-02-19 2:12 p.m., Laszlo Ersek wrote:
> Hi Ankur,
> 
> On 02/19/21 10:04, Ankur Arora wrote:
>> Hi,
>>
>> This series adds OVMF support for CPU hot-unplug.
>>
>> QEMU secureboot hot-unplug logic corresponding to this is in upstream.
>> Also posted here:
>>    https://lore.kernel.org/qemu-devel/20201207140739.3829993-1-imammedo@redhat.com/
>>
>> Testing (with QEMU 5.2.50):
>>   - Stable with randomized CPU plug/unplug (guest maxcpus=33,128)
>>   - Synthetic tests with simultaneous multi CPU hot-unplug
>>
>> Also at:
>>    github.com/terminus/edk2/ hot-unplug-v7
>>
>> Changelog:
>>
>> v7:
>>    - Address review comments from v6.
>>    - Fix ejection bug where we were using APIC ID to do the ejection
>>      rather than the Qemu Selector.
>>    - Describes safety properties and ordering needed for concurrent
>>      accesses to CPU_HOT_EJECT_DATA->QemuSelectorMap, and
>>      CPU_HOT_EJECT_DATA->Handler,
> 
> I plan to review this series early next week.

Thanks.

> This work is now going to miss the upcoming stable tag (soft feature
> freeze is 2021-02-22 00:00:00 UTC-8), but we can hopefully merge it
> early in the next development cycle.

Yeah, I did get a little late with v7.

> 
> Meanwhile, based on my github notifications folder, I believe you may
> not have put this version of the series through CI -- if that's correct,
> then please consider doing it.

I hadn't. Will do.

Thanks
Ankur

> 
> Thanks!
> Laszlo
> 
>>
>> v6:
>>    - addresses v5 review comments.
>>    URL: https://patchew.org/EDK2/20210129005950.467638-1-ankur.a.arora@oracle.com/
>>
>> v5:
>>    - fixes ECC errors (all but one in "OvmfPkg/CpuHotplugSmm: add
>>      add Qemu Cpu Status helper").
>>    URL: https://patchew.org/EDK2/20210126064440.299596-1-ankur.a.arora@oracle.com/
>>
>> v4:
>>    - Gets rid of unnecessary UefiCpuPkg changes
>>    URL: https://patchew.org/EDK2/20210118063457.358581-1-ankur.a.arora@oracle.com/
>>
>> 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.
>>
>> Thanks
>> Ankur
>>
>> Ankur Arora (10):
>>    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/SmmCpuFeaturesLib: call CPU hot-eject handler
>>    OvmfPkg/CpuHotplugSmm: add EjectCpu()
>>    OvmfPkg/CpuHotplugSmm: do actual CPU hot-eject
>>    OvmfPkg/SmmControl2Dxe: negotiate CPU hot-unplug
>>
>>   OvmfPkg/OvmfPkg.dec                                |   4 +
>>   OvmfPkg/CpuHotplugSmm/CpuHotplugSmm.inf            |   2 +
>>   .../SmmCpuFeaturesLib/SmmCpuFeaturesLib.inf        |   4 +
>>   OvmfPkg/CpuHotplugSmm/QemuCpuhp.h                  |   7 +
>>   OvmfPkg/Include/IndustryStandard/QemuCpuHotplug.h  |   2 +
>>   OvmfPkg/Include/Pcd/CpuHotEjectData.h              |  52 ++
>>   OvmfPkg/CpuHotplugSmm/CpuHotplug.c                 | 578 +++++++++++++++++----
>>   OvmfPkg/CpuHotplugSmm/QemuCpuhp.c                  | 106 +++-
>>   .../Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.c  | 136 +++++
>>   OvmfPkg/SmmControl2Dxe/SmiFeatures.c               |  18 +-
>>   10 files changed, 789 insertions(+), 120 deletions(-)
>>   create mode 100644 OvmfPkg/Include/Pcd/CpuHotEjectData.h
>>
>