[PATCH V7 0/8] Add architecture agnostic code to support vCPU Hotplug

Salil Mehta via posted 8 patches 1 year ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/qemu tags/patchew/20231113201236.30668-1-salil.mehta@huawei.com
Maintainers: Paolo Bonzini <pbonzini@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, Igor Mammedov <imammedo@redhat.com>, Ani Sinha <anisinha@redhat.com>, "Alex Bennée" <alex.bennee@linaro.org>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Richard Henderson <richard.henderson@linaro.org>, Eduardo Habkost <eduardo@habkost.net>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Yanan Wang <wangyanan55@huawei.com>, Peter Xu <peterx@redhat.com>, David Hildenbrand <david@redhat.com>
There is a newer version of this series
accel/kvm/kvm-all.c                    | 64 ++++++++++++++++++++------
accel/kvm/trace-events                 |  4 ++
docs/specs/acpi_hw_reduced_hotplug.rst |  3 +-
gdbstub/gdbstub.c                      | 12 +++++
hw/acpi/acpi-cpu-hotplug-stub.c        |  6 +++
hw/acpi/cpu.c                          | 27 +++++++----
hw/acpi/generic_event_device.c         | 21 +++++++++
hw/i386/acpi-build.c                   |  3 +-
include/exec/cpu-common.h              |  8 ++++
include/exec/gdbstub.h                 |  5 ++
include/hw/acpi/cpu.h                  |  5 +-
include/hw/acpi/cpu_hotplug.h          |  4 ++
include/hw/acpi/generic_event_device.h |  4 ++
include/hw/core/cpu.h                  |  1 +
include/sysemu/kvm.h                   | 16 +++++++
system/physmem.c                       | 29 ++++++++++++
16 files changed, 184 insertions(+), 28 deletions(-)
[PATCH V7 0/8] Add architecture agnostic code to support vCPU Hotplug
Posted by Salil Mehta via 1 year ago
Virtual CPU hotplug support is being added across various architectures[1][3].
This series adds various code bits common across all architectures:

1. vCPU creation and Parking code refactor [Patch 1]
2. Update ACPI GED framework to support vCPU Hotplug [Patch 2,3]
3. ACPI CPUs AML code change [Patch 4,5]
4. Helper functions to support unrealization of CPU objects [Patch 6,7]
5. Docs [Patch 8]


Repository:

[*] https://github.com/salil-mehta/qemu.git virt-cpuhp-armv8/rfc-v2.common.v7


Revision History:

Patch-set  V6 -> V7
1. Addressed Alex Bennée's comments
   - Updated the docs
2. Addressed Igor Mammedov's comments
   - Merged patches [Patch V6 3/9] & [Patch V6 7/9] with [Patch V6 4/9]
   - Updated commit-log of [Patch V6 1/9] and [Patch V6 5/9]     
3. Added Shaoqin Huang's Reviewed-by tags for whole series.
Link: https://lore.kernel.org/qemu-devel/20231013105129.25648-1-salil.mehta@huawei.com/

Patch-set  V5 -> V6
1. Addressed Gavin Shan's comments
   - Fixed the assert() ranges of address spaces
   - Rebased the patch-set to latest changes in the qemu.git
   - Added Reviewed-by tags for patches {8,9}
2. Addressed Jonathan Cameron's comments
   - Updated commit-log for [Patch V5 1/9] with mention of trace events
   - Added Reviewed-by tags for patches {1,5}
3. Added Tested-by tags from Xianglai Li
4. Fixed checkpatch.pl error "Qemu -> QEMU" in [Patch V5 1/9] 
Link: https://lore.kernel.org/qemu-devel/20231011194355.15628-1-salil.mehta@huawei.com/

Patch-set  V4 -> V5
1. Addressed Gavin Shan's comments
   - Fixed the trace events print string for kvm_{create,get,park,destroy}_vcpu
   - Added Reviewed-by tag for patch {1}
2. Added Shaoqin Huang's Reviewed-by tags for Patches {2,3}
3. Added Tested-by Tag from Vishnu Pajjuri to the patch-set
4. Dropped the ARM specific [Patch V4 10/10]
Link: https://lore.kernel.org/qemu-devel/20231009203601.17584-1-salil.mehta@huawei.com/

Patch-set  V3 -> V4
1. Addressed David Hilderbrand's comments
   - Fixed the wrong doc comment of kvm_park_vcpu API prototype
   - Added Reviewed-by tags for patches {2,4}
Link: https://lore.kernel.org/qemu-devel/20231009112812.10612-1-salil.mehta@huawei.com/

Patch-set  V2 -> V3
1. Addressed Jonathan Cameron's comments
   - Fixed 'vcpu-id' type wrongly changed from 'unsigned long' to 'integer'
   - Removed unnecessary use of variable 'vcpu_id' in kvm_park_vcpu
   - Updated [Patch V2 3/10] commit-log with details of ACPI_CPU_SCAN_METHOD macro
   - Updated [Patch V2 5/10] commit-log with details of conditional event handler method
   - Added Reviewed-by tags for patches {2,3,4,6,7}
2. Addressed Gavin Shan's comments
   - Remove unnecessary use of variable 'vcpu_id' in kvm_par_vcpu
   - Fixed return value in kvm_get_vcpu from -1 to -ENOENT
   - Reset the value of 'gdb_num_g_regs' in gdb_unregister_coprocessor_all
   - Fixed the kvm_{create,park}_vcpu prototypes docs
   - Added Reviewed-by tags for patches {2,3,4,5,6,7,9,10}
3. Addressed one earlier missed comment by Alex Bennée in RFC V1
   - Added traces instead of DPRINTF in the newly added and some existing functions
Link: https://lore.kernel.org/qemu-devel/20230930001933.2660-1-salil.mehta@huawei.com/

Patch-set V1 -> V2
1. Addressed Alex Bennée's comments
   - Refactored the kvm_create_vcpu logic to get rid of goto
   - Added the docs for kvm_{create,park}_vcpu prototypes
   - Splitted the gdbstub and AddressSpace destruction change into separate patches
   - Added Reviewed-by tags for patches {2,10}
Link: https://lore.kernel.org/qemu-devel/20230929124304.13672-1-salil.mehta@huawei.com/

References:

[1] https://lore.kernel.org/qemu-devel/20230926100436.28284-1-salil.mehta@huawei.com/
[2] https://lore.kernel.org/all/20230913163823.7880-1-james.morse@arm.com/
[3] https://lore.kernel.org/qemu-devel/cover.1695697701.git.lixianglai@loongson.cn/



Salil Mehta (8):
  accel/kvm: Extract common KVM vCPU {creation,parking} code
  hw/acpi: Move CPU ctrl-dev MMIO region len macro to common header file
  hw/acpi: Update ACPI GED framework to support vCPU Hotplug
  hw/acpi: Update GED _EVT method AML with CPU scan
  hw/acpi: Update CPUs AML with cpu-(ctrl)dev change
  physmem: Add helper function to destroy CPU AddressSpace
  gdbstub: Add helper function to unregister GDB register space
  docs/specs/acpi_hw_reduced_hotplug: Add the CPU Hotplug Event Bit

 accel/kvm/kvm-all.c                    | 64 ++++++++++++++++++++------
 accel/kvm/trace-events                 |  4 ++
 docs/specs/acpi_hw_reduced_hotplug.rst |  3 +-
 gdbstub/gdbstub.c                      | 12 +++++
 hw/acpi/acpi-cpu-hotplug-stub.c        |  6 +++
 hw/acpi/cpu.c                          | 27 +++++++----
 hw/acpi/generic_event_device.c         | 21 +++++++++
 hw/i386/acpi-build.c                   |  3 +-
 include/exec/cpu-common.h              |  8 ++++
 include/exec/gdbstub.h                 |  5 ++
 include/hw/acpi/cpu.h                  |  5 +-
 include/hw/acpi/cpu_hotplug.h          |  4 ++
 include/hw/acpi/generic_event_device.h |  4 ++
 include/hw/core/cpu.h                  |  1 +
 include/sysemu/kvm.h                   | 16 +++++++
 system/physmem.c                       | 29 ++++++++++++
 16 files changed, 184 insertions(+), 28 deletions(-)

-- 
2.34.1


Re: [PATCH V7 0/8] Add architecture agnostic code to support vCPU Hotplug
Posted by Igor Mammedov 1 year ago
On Mon, 13 Nov 2023 20:12:28 +0000
Salil Mehta <salil.mehta@huawei.com> wrote:

> Virtual CPU hotplug support is being added across various architectures[1][3].
> This series adds various code bits common across all architectures:
> 
> 1. vCPU creation and Parking code refactor [Patch 1]
> 2. Update ACPI GED framework to support vCPU Hotplug [Patch 2,3]
> 3. ACPI CPUs AML code change [Patch 4,5]
> 4. Helper functions to support unrealization of CPU objects [Patch 6,7]
> 5. Docs [Patch 8]
[...]

forgot to mention, you probably need to add to series migration code as well
as it should be the same for both targets.
(mostly copy-paste from q35 or piix4 and making sure it doesn't break old qemu
(aka not enabled/sent over wire if cpu hotplug event is disabled))
Re: [PATCH V7 0/8] Add architecture agnostic code to support vCPU Hotplug
Posted by Igor Mammedov 1 year ago
On Mon, 13 Nov 2023 20:12:28 +0000
Salil Mehta <salil.mehta@huawei.com> wrote:

[...]
>   physmem: Add helper function to destroy CPU AddressSpace
>   gdbstub: Add helper function to unregister GDB register space
[...]

above patches look like potential bugfixes (modulo they aren't getting used actually),
only commit messages do not mention adverse effects (which they should do).

Question is:
    do un-destroyed/registered CPU AS and GDB RS affect machines that
    already support cpu hot-unplug? (x86/s380/spapr)