[PATCH v8 00/10] support CPU hot-unplug

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

Hi,

[ Note, v8 is substantially same as v7, but fixes a couple of CI errors. ]

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-v8

Changelog:

v8:
  - Fixes a couple of ECC issues in the code (in patches 7, 9)

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.
  URL: https://patchew.org/EDK2/20210219090444.1332380-1-ankur.a.arora@oracle.com/

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                 | 583 +++++++++++++++++----
 OvmfPkg/CpuHotplugSmm/QemuCpuhp.c                  | 106 +++-
 .../Library/SmmCpuFeaturesLib/SmmCpuFeaturesLib.c  | 138 +++++
 OvmfPkg/SmmControl2Dxe/SmiFeatures.c               |  18 +-
 10 files changed, 796 insertions(+), 120 deletions(-)
 create mode 100644 OvmfPkg/Include/Pcd/CpuHotEjectData.h

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2.9.3