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

[Michael S. Tsirkin]

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 <address@hidden>

Since Eduardo picked up first part of this, feel free
to merge the rest too.



>   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: address@hidden
> CC: address@hidden
> CC: address@hidden
> CC: address@hidden
> CC: Bandan Das <address@hidden>
> 
> 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