[Qemu-devel] [RFC 00/34] QOM realize, device-only plus ISA conversion

[Andreas Färber]

Hello Anthony and Paolo,

As announced at KVM Forum, I have been preparing a new approach to incrementally
get us Anthony's QOM realizefn concept. A previous attempt by Paolo and me had
been turned down for making this available at Object-level and over questions
whether BlockDriverState may need its own three-stage realization model.

So here's an all-new patchset doing it at DeviceState-level only, adapting the
signature to void realize(DeviceState *, Error **).
CPUState is on a good way to get derived from DeviceState, so in the future
will benefit from this approach as well.

I've picked ISADevice as an example to showcase what semantic effects the
switch to QOM realizefn has (in the hopes the number of devices would be small):
As requested by Anthony for QOM CPUState reset and as seen with virtual methods
in object-oriented programming languages, it becomes the derived method's
responsibility to decide when and whether to call the parent class' method. In
lack of real vtables this requires to save the parent's method in case we want
to call it; classes and matching macros may need to be added for that.
Another point to note is that we should carefully distinguish what goes into
the qdev initfn / QOM realizefn and what can already go into a QOM initfn.

This series is rebased onto Julien's ioport cleanups (touching on ISA devices).

It starts by preparing the "realized" property, wrapping qdev's initfn (04).
This means setting realized to true will not yet affect its children, as seen
in Paolo's previous patches. That can be implemented later when the realizefns
have been reviewed not to create new devices that would mess with recursive
child realization. (In the previous series we had recursive realization but
on my request dropped the hook-up of qdev due to the aforementioned quirks.)

At that point there is a coexistence of QOM device realizefn and qdev initfn.
For the first time now I have set out to actually eliminate some qdev initfns,
that's what I chose ISA for. This consists of three parts, introducing
realizefns for ISADevices (28) and recursively for PITs (31) and for PICs (34).
As seen for the PCI host bridge series, I've extracted general QOM cleanups
from the main conversion patch to arrive at a clean QOM'ish state while
hopefully keeping the main patches readable.

This series also highlights an interesting find: Beyond the to-be-solved
CPUState, there is also a "realize" function for BusState (02), which is not
derived from DeviceState. :-)
With the device-centric approach taken here it would still be possible to add
"realized" properties to other types using their own infrastructure (e.g., a
hardcoded setter rather than a realizefn hook).

Posted as an RFC to encourage bikeshedding, in particular about the type names
and macros introduced. Adding new header files to move them out of the source
files for, e.g., vl.c is left for a follow-up, but for instance I was unsure
about TYPE_ISA_FDC (should this be TYPE_ISA_FLOPPY_DRIVE_CONTROLLER as with
PCI_HOST_BRIDGE rather than PHB?), and naming of type names and functions is
highly inconsistent (e.g., isa_vga vs. vga_isa, or pic vs. i8259).

Available for viewing/testing at:
https://github.com/afaerber/qemu-cpu/commits/realize-qdev
git://github.com/afaerber/qemu-cpu.git realize-qdev

Regards,
Andreas

Cc: Anthony Liguori <address@hidden>
Cc: Paolo Bonzini <address@hidden>

Cc: Julien Grall <address@hidden>
Cc: Frederic Konrad <address@hidden>
Cc: Peter Maydell <address@hidden>
Cc: Cornelia Huck <address@hidden>
Cc: Kevin Wolf <address@hidden>
Cc: Stefan Hajnoczi <address@hidden>
Cc: Markus Armbruster <address@hidden>
Cc: Eduardo Habkost <address@hidden>
Cc: Igor Mammedov <address@hidden>

Andreas Färber (34):
  qdev: Eliminate qdev_free() in favor of QOM
  qbus: QOM'ify qbus_realize()
  qdev: Fold state enum into bool realized
  qdev: Prepare "realized" property
  isa: Split off instance_init for ISADevice
  applesmc: QOM'ify
  cirrus_vga: QOM'ify ISA Cirrus VGA
  debugcon: QOM'ify ISA debug console
  fdc: QOM'ify ISA floppy controller
  i82374: QOM'ify
  i8259: Fix PIC_COMMON() macro
  i8259: QOM cleanups
  ide: QOM'ify ISA IDE
  m48t59: QOM'ify ISA M48T59 NVRAM
  mc146818rtc: QOM'ify
  ne2000-isa: QOM'ify
  parallel: QOM'ify
  pc: QOM'ify port 92
  pckbd: QOM'ify
  pcspk: QOM'ify
  sb16: QOM'ify
  serial: QOM'ify ISA serial
  sga: QOM'ify
  vga-isa: QOM'ify ISA VGA
  vmmouse: QOM'ify
  vmport: QOM'ify
  wdt_ib700: QOM'ify
  isa: Use realizefn for ISADevice
  i8254: QOM'ify
  kvm/i8254: QOM'ify some more
  i8254: Convert PITCommonState to QOM realizefn
  i8259: QOM'ify some more
  kvm/i8259: QOM'ify some more
  i8259: Convert PICCommonState to use QOM realizefn

 hw/acpi_piix4.c      |    2 +-
 hw/applesmc.c        |   45 +++++++++---------
 hw/cirrus_vga.c      |   27 ++++++-----
 hw/debugcon.c        |   34 +++++++++-----
 hw/fdc.c             |   45 ++++++++++--------
 hw/fdc.h             |    2 +
 hw/i82374.c          |   25 +++++-----
 hw/i8254.c           |   26 +++++++---
 hw/i8254.h           |    7 ++-
 hw/i8254_common.c    |   19 ++------
 hw/i8254_internal.h  |    1 -
 hw/i8259.c           |   64 +++++++++++++++++--------
 hw/i8259_common.c    |   20 +++-----
 hw/i8259_internal.h  |    7 +--
 hw/ide/isa.c         |   55 +++++++++++++---------
 hw/isa-bus.c         |   15 ++----
 hw/isa.h             |    1 -
 hw/kvm/i8254.c       |   59 +++++++++++++++--------
 hw/kvm/i8259.c       |   38 ++++++++++++---
 hw/m48t59.c          |   54 +++++++++++----------
 hw/mc146818rtc.c     |   56 ++++++++++++----------
 hw/mc146818rtc.h     |    2 +
 hw/ne2000-isa.c      |   27 ++++++-----
 hw/parallel.c        |   42 ++++++++++-------
 hw/pc.c              |   26 +++++-----
 hw/pc_piix.c         |    2 +-
 hw/pci-hotplug.c     |    2 +-
 hw/pci_bridge.c      |    2 +-
 hw/pcie.c            |    2 +-
 hw/pckbd.c           |   34 ++++++++------
 hw/pcspk.c           |   21 +++++----
 hw/pcspk.h           |    4 +-
 hw/qdev-addr.c       |    2 +-
 hw/qdev-core.h       |   12 ++---
 hw/qdev-monitor.c    |    2 +-
 hw/qdev-properties.c |   28 +++++------
 hw/qdev.c            |  128 ++++++++++++++++++++++++++++++++++----------------
 hw/sb16.c            |   35 +++++++++-----
 hw/scsi-bus.c        |    4 +-
 hw/serial-isa.c      |   33 +++++++------
 hw/serial-pci.c      |    4 +-
 hw/serial.c          |    6 +--
 hw/serial.h          |    3 +-
 hw/sga.c             |   19 ++++----
 hw/shpc.c            |    2 +-
 hw/usb/bus.c         |    7 +--
 hw/usb/dev-storage.c |    2 +-
 hw/usb/host-linux.c  |    2 +-
 hw/vga-isa.c         |   46 +++++++++---------
 hw/vmmouse.c         |   24 +++++-----
 hw/vmport.c          |   24 ++++++----
 hw/wdt_ib700.c       |   22 +++++----
 hw/xen_platform.c    |    2 +-
 53 Dateien geändert, 692 Zeilen hinzugefügt(+), 481 Zeilen entfernt(-)

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