[Qemu-devel] [PATCH v2 0/9] s390: Allow hotplug of s390 CPUs

[Matthew Rosato]

Changes from v1->v2:

* Remove cpu-add support.  Instead use 'device_add s390-cpu'
* Add unplug support via 'device_del'.
* Pull in 2 patches from pseries set.  Patch 1 just required some rebasing.
  Patch 2 required minor changes due to previous upstream review comments.

**************

The following patchset enables hotplug of s390 CPUs.

The standard interface is used -- to configure a guest with 2 CPUs online at 
boot and 4 maximum:

qemu -smp 2,maxcpus=4

To subsequently hotplug a CPU:

Issue 'device_add s390-cpu,id=<id>' from monitor.

At this point, the guest must bring the CPU online for use -- This can be 
achieved via "echo 1 > /sys/devices/system/cpu/cpuX/online" or via a management 
tool like cpuplugd.

Hot unplug support is provided via 'device_del <id>', however s390 does not have
a mechanism for gracefully handling a CPU that has been removed, so this event
triggers a reset of the guest in order to force recognition.  

This patch set is based on work previously done by Jason Herne.

Bharata B Rao (1):
  cpus: Add a sync version of cpu_remove()

Matthew Rosato (8):
  cpus: Reclaim vCPU objects
  s390x/cpu: Cleanup init in preparation for hotplug
  s390x/cpu: Set initial CPU state in common routine
  s390x/cpu: Move some CPU initialization into realize
  s390x/cpu: Add functions to (un)register CPU state
  s390x/cpu: Extra cleanup during CPU finalize
  s390/virtio-ccw: Add hotplug handler and prepare for unplug
  s390x/cpu: Allow hot plug/unplug of CPUs

 cpus.c                     | 53 +++++++++++++++++++++++++++++
 hw/s390x/s390-virtio-ccw.c | 30 ++++++++++++++++-
 hw/s390x/s390-virtio.c     | 66 ++++++++++++++++++++++++++----------
 hw/s390x/s390-virtio.h     |  2 +-
 include/qom/cpu.h          | 18 ++++++++++
 include/sysemu/kvm.h       |  1 +
 kvm-all.c                  | 57 ++++++++++++++++++++++++++++++-
 kvm-stub.c                 |  5 +++
 target-s390x/cpu.c         | 83 +++++++++++++++++++++++++++++++++++++++++++---
 target-s390x/cpu.h         |  4 +++
 10 files changed, 295 insertions(+), 24 deletions(-)

-- 
1.9.1