[V10,0/8] Add architecture agnostic code to support vCPU Hotplug

Message

Salil Mehta May 20, 2024, 11:32 p.m. UTC

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-v3.arch.agnostic.v10

NOTE: For ARM, above will work in combination of the architecture specific part based on
RFC V2 [1]. This architecture specific patch-set RFC V3 shall be floated soon and is present
at below location

[*] https://github.com/salil-mehta/qemu/tree/virt-cpuhp-armv8/rfc-v3-rc1


Revision History:

Patch-set  V9 -> V10
1. Addressed Nicholas Piggin's (IBM) & Philippe Mathieu-Daudé (Linaro) comments
   - carved out kvm_unpark_vcpu and added its trace
   - Widened the scope of the kvm_unpark_vcpu so that it can be used by generic framework
     being thought out
Link: https://lore.kernel.org/qemu-devel/[e-mail]/
Link: https://lore.kernel.org/qemu-devel/[e-mail]/

Patch-set  V8 -> V9
1. Addressed Vishnu Pajjuri's (Ampere) comments
   - Added kvm_fd to trace in kvm_create_vcpu
   - Some clean ups: arch vcpu-id and sbd variable
   - Added the missed initialization of cpu->gdb_num_regs
2. Addressed the commnet from Zhao Liu (Intel)
   - Make initialization of CPU Hotplug state conditional (possible_cpu_arch_ids!=NULL)
Link: https://lore.kernel.org/qemu-devel/[e-mail]/

Patch-set V7 -> V8
1. Rebased and Fixed the conflicts

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/[e-mail]/

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/[e-mail]/

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/[e-mail]/

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/[e-mail]/

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/[e-mail]/

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/[e-mail]/

References:

[1] https://lore.kernel.org/qemu-devel/[e-mail]/
[2] https://lore.kernel.org/all/[e-mail]/
[3] https://lore.kernel.org/qemu-devel/[e-mail]/



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                    | 97 +++++++++++++++++---------
 accel/kvm/kvm-cpus.h                   | 23 ++++++
 accel/kvm/trace-events                 |  5 +-
 docs/specs/acpi_hw_reduced_hotplug.rst |  3 +-
 gdbstub/gdbstub.c                      | 13 ++++
 hw/acpi/acpi-cpu-hotplug-stub.c        |  6 ++
 hw/acpi/cpu.c                          | 33 ++++++---
 hw/acpi/generic_event_device.c         | 21 ++++++
 hw/core/cpu-common.c                   |  1 -
 hw/i386/acpi-build.c                   |  3 +-
 include/exec/cpu-common.h              |  8 +++
 include/exec/gdbstub.h                 |  6 ++
 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 +
 system/physmem.c                       | 29 ++++++++
 17 files changed, 214 insertions(+), 48 deletions(-)