[Qemu-devel] [PATCH 0/5 v9 for-1.5] target-i386: CPU hot-add with cpu-add QMP command

[Igor Mammedov <imammedo@redhat.com>]

Implements alternative way for hot-adding CPU using cpu-add QMP command,
which could be useful until it would be possible to add CPUs via device_add.

To hot-add CPU use following command from qmp-shell:
 cpu-add id=[0..max-cpus - 1)

git tree for testing: https://github.com/imammedo/qemu/tree/cpu_add.v9

based on qom-cpu tree

v9->v7:
  * replace machine.cpu-model option with cpu_model field in QEMUMachine
  * x86: set default cpu_model statically in each machine and get it
    from there if user haven't provided it.

v8->v7:
  * skip already applied patches
  * split adding hot_add_cpu hook into separate function
  * add cpu-model machine option and use QemuOpts for getting it
    during CPU hotplug.

v7->v6:
  * skip already applied patches
  * rename icc-bus instance name to "icc"
  * pass icc_bridge from board as argument down CPU creation call chain,
    instead of dynamically resolving it for each CPU.

v6->v5:
  * override hot_add_cpu hook statically
  * extend and use memory_region_find() in IOAPIC
  * s/signal_cpu_creation/tcg_signal_cpu_creation/
  * add "since 1.5 to cpu-addQAPI schema description

v5->v4:
  * style fixes
  * new helper qemu_for_each_cpu()
  * switch to qemu_for_each_cpu() in cpu_exists()
  * "pc: update rtc ..." patch make depend it on "mc146818rtc: QOM'ify"
    and use QOM cast style
  * call CPU added notifier right before CPU becomes runable
  * s/resume_vcpu/cpu_resume/
  * acpi/piix4: add spec documentation for QEMU<->Seabios CPU hotplug
    interface
  * use error_propagate() in pc_new_cpu()
  * skip cpu_exists() check in apic-id property setter if new value is
    the same as current
  * embed icc-bus inside icc-bridge and use qbus_create_inplace()
  * move include/hw/i386/icc_bus.h into include/hw/cpu/
  * make missing icc-bus fatal error for softmmu target
  * split "move APIC to ICC bus" and "move IOAPIC to ICC bus" on smaller
    patches
  * use qdev_get_parent_bus() to get parent bus
  * split "add cpu-add command..." on smaller patches

v4->v3:
  * 'id' in cpu-add command will be a thread number instead of APIC ID
  * split off resume_vcpu() into separate patch
  * move notifier from rtc code into pc.c

v2->v3:
  * use local error & propagate_error() instead of operating on
    passed in errp in several places
  * replace CPUClass.get_firmware_id() with CPUClass.get_arch_id()
  * leave IOAPIC creation to board and just set bus to icc-bus
  * include kvm-stub.o in cpu libary if no KVM is configured
  * create resume_vcpu() stub and include it in libqemustub,
    and use it directly instead of CPU method
  * acpi_piix4: s/cpu_add_notifier/cpu_added_notifier/

v1->v2:
  * generalize cpu sync to KVM, resume and hot-plug notification and
    invoke them form CPUClass, to make available to all targets.
  * introduce cpu_exists() and CPUClass.get_firmware_id() and use
    the last one in acpi_piix to make code target independent.
  * move IOAPIC to ICC bus, it was suggested and easy to convert.
  * leave kvmvapic as SysBusDevice, it doesn't affect hot-plug and
    created only once for all APIC instances. I haven't found yet
    good/clean enough way to convert it to ICCDevice. May be follow-up
    though.
  * split one big ICC patch into several, one per converted device
  * add cpu_hot_add hook to machine and implement it for target-i386,
    instead of adding stabs. Could be used by other targets to
    implement cpu-add.
  * pre-allocate links<CPU> for all possible CPUs and make them available
    at /machine/icc-bridge/cpu[0..N] QOM path, so users could find out
    possible/free CPU IDs to use in cpu-add command.



Igor Mammedov (5):
  add hot_add_cpu hook to QEMUMachine
  QMP: add cpu-add command
  add cpu_model to QEMUMachine
  target-i386: get default cpu_model from QEMUMachine
  target-i386: implement machine->hot_add_cpu hook

 hw/i386/pc.c         |   32 +++++++++++++++++++++++---------
 hw/i386/pc_piix.c    |   17 +++++++++++++++--
 hw/i386/pc_q35.c     |    3 +++
 include/hw/boards.h  |    2 ++
 include/hw/i386/pc.h |    1 +
 qapi-schema.json     |   13 +++++++++++++
 qmp-commands.hx      |   23 +++++++++++++++++++++++
 qmp.c                |   10 ++++++++++
 target-i386/cpu.h    |    6 ++++++
 vl.c                 |    6 ++++++
 10 files changed, 102 insertions(+), 11 deletions(-)