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

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

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.

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.

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.

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
>