Re: [Qemu-devel] [PATCH v2 00/10] ACPI CPU hotplug refactoring to support unplug and more than 255 CPUs

[Igor Mammedov]

On Tue, 21 Jun 2016 19:50:14 +0300
"Michael S. Tsirkin" <address@hidden> wrote:

> On Tue, Jun 21, 2016 at 09:12:38AM +0200, Igor Mammedov wrote:
> > On Thu, 16 Jun 2016 18:55:33 +0200
> > Igor Mammedov <address@hidden> wrote:
> > 
> > Michael,
> > Do you think that this series will make into 2.7?
> 
> Yes, I think it will. I'll try to prioritize review.
Thanks,

then I'll try to post dependent x2APIC and 'device-add cpu' series
ASAP.

> 
> > > Changelog:                                                                
> > >        
> > >  v1->v2:                                                                  
> > >        
> > >   - dropped consolidate legacy ACPI CPU hotplug as they are in
> > > master by now     
> > >   - pc: start with legacy hotplug and let 2.7 machine type and
> > > older to switch inot new hotplug mode. That way legacy BIOS
> > > will still work fine as it uses built in ACPI tables and will
> > > continue to use legacy CPU hotplug
> > > interface.                                         
> > >   - poll for CPU objects with events (insert/remove) instead
> > > of looping over all CPUs to find CPUs with
> > > events.                              
> > >   - drop dynamic PXM support as it could be implemented in static
> > > way at acpi tabels build time. It will be an additional series on
> > > top of this.   
> > >   - resplit patches on basic present CPU support, hot-add and
> > > hot-remove parts
> > > Patches: 1-7: add new CPU hotplug
> > > impl. 8: makes 2.7 machine type to use new AML code
> > > that will switch piix4/ich9 into new mode
> > > + switching logic with migration glue for
> > > piix4/ich9 9: drops the last dependency in ACPI parts on
> > > apic_id_limit sized
> > > map.
> > > RFC->v1:                                                                  
> > >       
> > >   - drop machine.cpu-hotplug property and leave CPU
> > > hotplug always enabled as it used to
> > > be. (it also simplifies, series a
> > > bit)                                           
> > >   - reshuffle/squash some patches to make series
> > > bisectable wrt 'make check'
> > > failures                                                    
> > >   - add doc comment in qapi
> > > schema                                               
> > >   - fix 'make check' error for mips target, disableCPU
> > > hotplug code path in piix4_pm for
> > > mips                                               
> > >   - drop some intermediate expected ACPI tables
> > > updates                          
> > >   - replace _MAT method with named buffer
> > > object 
> > > Current ACPI interface for CPU hotplug supports
> > > hoti-adding only upto 255 CPUs and lacks means to convey
> > > additional information needed _OST methods
> > > support. Also being bitmap based with bit position specifying APIC
> > > ID it doesn't scale up well for 32-bit APIC IDs that will
> > > come with x2APIC
> > > support. 
> > > So add another QEMU-guest interface using as model
> > > memory-hotplug. New interface will be used since 2.7 machine types
> > > and will
> > > support:                                                                  
> > >        
> > >     - more than 255 CPUs with 32-bit APIC ID
> > > value                               
> > >     - a registers set to communicate OST
> > > information (extendable without breaking IO
> > > layout)                                    
> > >     - possible to reuse for ARM's 'virt' machine
> > > type with minimal tweaks (add init for MMIO,
> > > add ACPI hooks on CPU hotplug path, MADT
> > > generation) 
> > >                                                                           
> > >        
> > > Tested with following guests: RHEL7, WS2003EEx64,
> > > WS2012R2x64                    
> > >  * unplug is tested only with RHEL7 as Windows doesn't support
> > > it.               
> > >  * tested that migration works as
> > > well. 
> > > git tree for
> > > testing: address@hidden:imammedo/qemu.git
> > > modern_cpu_hotplug_v2
> > > viewing:
> > > https://github.com/imammedo/qemu/commits/modern_cpu_hotplug_v2            
> > >    
> > > 
> > > Igor Mammedov (10):
> > >   docs: update ACPI CPU hotplug spec with new protocol
> > >   pc: piix4/ich9: add 'cpu-hotplug-legacy' property
> > >   acpi: cpuhp: add CPU devices AML with _STA method
> > >   pc: acpi: introduce AcpiDeviceIfClass.madt_cpu hook
> > >   acpi: cpuhp: implement hot-add parts of CPU hotplug interface
> > >   acpi: cpuhp: implement hot-remove parts of CPU hotplug interface
> > >   acpi: cpuhp: add cpu._OST handling
> > >   pc: use new CPU hotplug interface since 2.7 machine type
> > >   tests: acpi: add CPU hotplug testcase
> > >   pc: acpi: drop intermediate PCMachineState.node_cpu
> > > 
> > >  docs/specs/acpi_cpu_hotplug.txt      |  94 +++++-
> > >  hw/acpi/Makefile.objs                |   1 +
> > >  hw/acpi/cpu.c                        | 561
> > > +++++++++++++++++++++++++++++++++++
> > > hw/acpi/cpu_hotplug.c                |  21 +-
> > > hw/acpi/ich9.c                       |  69 ++++-
> > > hw/acpi/piix4.c                      |  71 ++++-
> > > hw/i386/acpi-build.c                 |  68 +++--
> > > hw/i386/pc.c                         |  63 +++-
> > > hw/i386/pc_piix.c                    |   2 +
> > > hw/i386/pc_q35.c                     |   2 +
> > > hw/isa/lpc_ich9.c                    |   1 +
> > > include/hw/acpi/acpi_dev_interface.h |   7 +
> > > include/hw/acpi/cpu.h                |  67 +++++
> > > include/hw/acpi/cpu_hotplug.h        |   6 +
> > > include/hw/acpi/ich9.h               |   3 +
> > > include/hw/i386/pc.h                 |   8 +-
> > > qapi-schema.json                     |   3 +-
> > > stubs/Makefile.objs                  |   1 +
> > > stubs/pc_madt_cpu_entry.c            |   7 +
> > > tests/bios-tables-test.c             |  28 ++
> > > trace-events                         |  14 + 21 files changed,
> > > 1043 insertions(+), 54 deletions(-) create mode 100644
> > > hw/acpi/cpu.c create mode 100644 include/hw/acpi/cpu.h
> > >  create mode 100644 stubs/pc_madt_cpu_entry.c
> > > 
> >