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

["Laszlo Ersek" <lersek@redhat.com>]

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.

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
>