[Qemu-devel] [PATCH 00/10] Clean up and fix no_user

[armbru@redhat.com]

From: Markus Armbruster <armbru@redhat.com>

In an ideal world, machines can be built by wiring devices together
with configuration, not code.  Unfortunately, that's not the world we
live in right now.  We still have quite a few devices that need to be
wired up by code.  If you try to device_add such a device, it'll fail
in sometimes mysterious ways.  If you're lucky, you get an
unmysterious immediate crash.

We used to protect users from such badness by marking devices where
device_add cannot possibly work "no-user", and refusing to device_add
them.  Anthony silently broke the protection in v1.1.  He has rejected
attempts to unbreak it with the argument that the protection makes it
impossible to wire devices together with configuration, not code, and
that the protection is being misused[*].

On the former, I disagree.  The problem isn't protecting users from
devices that cannot be wired up that way, it's devices that cannot be
wired up that way.

On the latter, Anthony has a point: the purpose of the no-user flag
isn't obvious, and some of its uses are suspect.

So, instead of just fixing the regression, this series first addresses
that point.  PATCH 1 clarifies the purpose of no-user.  PATCH 2-9
clean up and document its use.  PATCH 10 fixes the regression.

Markus Armbruster (10):
  qdev: Replace no_user by cannot_instantiate_with_device_add_yet
  sysbus: Set cannot_instantiate_with_device_add_yet
  cpu: Document why cannot_instantiate_with_device_add_yet
  apic: Document why cannot_instantiate_with_device_add_yet
  pci-host: Consistently set cannot_instantiate_with_device_add_yet
  ich9: Document why cannot_instantiate_with_device_add_yet
  piix3 piix4: Clean up use of cannot_instantiate_with_device_add_yet
  vt82c686: Clean up use of cannot_instantiate_with_device_add_yet
  isa: Clean up use of cannot_instantiate_with_device_add_yet
  qdev: Do not let the user try to device_add when it cannot work

 hw/acpi/piix4.c            |  7 ++++++-
 hw/alpha/typhoon.c         |  2 --
 hw/arm/versatilepb.c       |  1 -
 hw/audio/pcspk.c           |  3 ++-
 hw/audio/pl041.c           |  1 -
 hw/block/fdc.c             |  1 -
 hw/core/sysbus.c           |  7 +++++++
 hw/display/pl110.c         |  1 -
 hw/dma/pl080.c             |  1 -
 hw/i2c/smbus_ich9.c        |  6 +++++-
 hw/i386/kvm/clock.c        |  1 -
 hw/i386/kvmvapic.c         |  1 -
 hw/i386/pc.c               |  1 -
 hw/ide/piix.c              |  3 ---
 hw/ide/via.c               |  1 -
 hw/input/pckbd.c           |  1 -
 hw/input/vmmouse.c         |  3 ++-
 hw/intc/apic_common.c      |  6 +++++-
 hw/intc/arm_gic.c          |  1 -
 hw/intc/arm_gic_common.c   |  1 -
 hw/intc/arm_gic_kvm.c      |  1 -
 hw/intc/i8259_common.c     |  8 +++++++-
 hw/intc/ioapic_common.c    |  1 -
 hw/intc/pl190.c            |  1 -
 hw/isa/isa-bus.c           |  1 -
 hw/isa/lpc_ich9.c          |  7 +++++--
 hw/isa/piix4.c             |  6 +++++-
 hw/isa/vt82c686.c          |  6 +++++-
 hw/mips/gt64xxx_pci.c      |  5 +++++
 hw/misc/arm_l2x0.c         |  1 -
 hw/misc/vmport.c           |  3 ++-
 hw/nvram/fw_cfg.c          |  1 -
 hw/pci-bridge/dec.c        |  5 +++++
 hw/pci-host/apb.c          |  5 +++++
 hw/pci-host/bonito.c       |  8 +++++---
 hw/pci-host/grackle.c      |  8 +++++---
 hw/pci-host/piix.c         | 19 +++++++++++++++----
 hw/pci-host/ppce500.c      |  5 +++++
 hw/pci-host/prep.c         |  7 +++++--
 hw/pci-host/q35.c          |  5 +++++
 hw/pci-host/uninorth.c     | 20 ++++++++++++++++++++
 hw/pci-host/versatile.c    |  5 +++++
 hw/ppc/ppc4xx_pci.c        |  5 +++++
 hw/ppc/spapr_vio.c         |  2 --
 hw/s390x/ipl.c             |  1 -
 hw/s390x/s390-virtio-bus.c |  2 --
 hw/s390x/virtio-ccw.c      |  2 --
 hw/sd/pl181.c              |  1 -
 hw/sh4/sh_pci.c            |  5 +++++
 hw/timer/arm_mptimer.c     |  1 -
 hw/timer/hpet.c            |  1 -
 hw/timer/i8254_common.c    |  1 -
 hw/timer/m48t59.c          |  1 -
 hw/timer/mc146818rtc.c     |  1 -
 hw/timer/pl031.c           |  1 -
 include/hw/qdev-core.h     | 13 ++++++++++++-
 qdev-monitor.c             |  7 ++++---
 qom/cpu.c                  |  6 +++++-
 58 files changed, 162 insertions(+), 65 deletions(-)

-- 
1.8.1.4