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

[Eduardo Otubo <eduardo.otubo@profitbricks.com>]

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On Tue, Jul 19, 2016 at 12=59=36AM +0300, Michael S. Tsirkin wrote:
> On Thu, Jul 14, 2016 at 06:54:29PM +0200, Igor Mammedov wrote:
> > Changelog:
> 
> So for pc and apic bits:
> 
> Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
> 
> Since Eduardo picked up first part of this, feel free
> to merge the rest too.

Hi Igor,

I was a little curios about the state of this feature. Is this going to
make it to 2.7?

Best regards,

> 
> 
> 
> >   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

-- 
Eduardo Otubo
ProfitBricks GmbH

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