[Qemu-devel] [PATCH v4 00/16] pc: add CPU hot-add/hot-remove with device_add/device_del

[Igor Mammedov <imammedo@redhat.com>]

Changelog:
  since v3:
    * rebase on top of x86-next tree as it's already applied 1-6/19 from v3
      (so they are could be omitted from v4)
    * set apic-state to NULL after destroying it in unrealize()
    * fix places where I forgot to print X86CPUTopoInfo fields as %u
    * move "pc: implement query-hotpluggable-cpus callback" after
      patch that enables device_add cpu
    * extract counting of present cpus in possible_cpus into a separate helper
    * newly added patches:
        * pc: forbid BSP removal
        * pc: enforce adding CPUs contiguously and removing them in opposit order
        * apic: kvm-apic: fix crash due to access to freed memory region
    * update Reviewed-bys
  since v2:
    * use 0xFFFFFFFF for UNASSIGNED_APIC_ID instead of UINT32_MAX
    * add comment why 0xFFFFFFFF could be used for UNASSIGNED_APIC_ID
    * print topo ids is unsigned
    * print APIC ID as hex
    * print topo ids calculated from APIC ID beside it
    * add extra patch to fix migration failure due to APIC's instance_id mismatch
  since v1:
    * s/pc_find_cpu/pc_find_cpu_slot/ + add comment to it
    * add more sanity checks for socket-id/core-id/thread-id and 'apic'
      properties
    * include device_del cpu patches and related fixes to x86 CPU/apic

Series enabling usage of -device/device_add for adding CPUs as devices
and device_del for removing them. Using -device/device_add in combination
with query-hotpluggable-cpus QMP command allows to hotplug CPUs at any
not used possition and then safely migrate QEMU instance by specifying
hotadded CPUs on target with help of -device CLI option like with any
other device.
Having been able to replicate exact topology on taggert with -device CPUs
also opens poosibility to hot-remove CPUs, which this series does by
enabling to use device_del with x86 CPUs.


git tree for testing:
  https://github.com/imammedo/qemu.git dev_del_cpu_v4
for viewing:
  https://github.com/imammedo/qemu/commits/dev_del_cpu_v4

Tested with RHEL7.2 guest including ping/pong migration with adding/removing
CPUs in between.

CC: pkrempa@redhat.com
CC: ehabkost@redhat.com
CC: mst@redhat.com
CC: eduardo.otubo@profitbricks.com
CC: Bandan Das <bdas@redhat.com>

Igor Mammedov (16):
  pc: set APIC ID based on socket/core/thread ids if it's not been set
    yet
  pc: delay setting number of boot CPUs to machine_done time
  pc: register created initial and hotpluged CPUs in one place
    pc_cpu_plug()
  pc: forbid BSP removal
  pc: enforce adding CPUs contiguously and removing them in opposit
    order
  pc: cpu: allow device_add to be used with x86 cpu
  pc: implement query-hotpluggable-cpus callback
  apic: move MAX_APICS check to 'apic' class
  apic: drop APICCommonState.idx and use APIC ID as index in
    local_apics[]
  apic: kvm-apic: fix crash due to access to freed memory region
  (kvm)apic: add unrealize callbacks
  apic: use apic_id as apic's migration instance_id
  target-i386: cpu: do not ignore error and fix apic parent
  target-i386: fix apic object leak when CPU is deleted
  target-i386: add x86_cpu_unrealizefn()
  pc: make device_del CPU work for x86 CPUs

 include/hw/i386/apic_internal.h |   5 +-
 include/hw/i386/pc.h            |   5 ++
 hw/i386/kvm/apic.c              |   9 +-
 hw/i386/pc.c                    | 183 ++++++++++++++++++++++++++++++++++------
 hw/intc/apic.c                  |  26 +++++-
 hw/intc/apic_common.c           |  33 ++++++--
 qmp-commands.hx                 |  15 ++++
 target-i386/cpu.c               |  23 ++++-
 8 files changed, 251 insertions(+), 48 deletions(-)

-- 
2.7.4