[Qemu-devel] [PATCH v4 00/30] virtio: cleanup, fix hot-unplug, move to realize

[Paolo Bonzini <pbonzini@redhat.com>]

This series fixes hot-unplug of virtio devices, which can crash due to
dangling pointer accesses.

The current implementation supports guest-initiated hot-unplug via the
virtio_bus_destroy_device function, but not hot-unplugging the virtio
device by virtue of unplugging its parent container device.

The problem is that the callback for the bus implementation to cleanup
is placed in the wrong place; it is in virtio_bus_destroy_device, which
should be called by the bus, instead of being somewhere in device code.
We need to have the callback in device code (for example in dc->exit),
so that we invoke it on every unplug action, no matter who starts it.

Thus, the series cleans up plugging and unplugging of virtio devices
so that it does not need any help from the bus (patches 2-5).  It then
stops the virtio devices' overriding of dc->exit, moving their cleanup
code to the new exit callback in VirtioDeviceClass (patches 6-11).
Finally, patch 12 can make virtio-pci implement the device_unplugged
callback.

A similar dangling-pointer bug is exposed by this change in virtio-ccw.
Patch 1 avoids this; it is kept at the beginning to ensure bisectability.

Patches 13-30 are Andreas's conversion of virtio to realize/unrealize,
which has better error propagation as shown by the small testcase fix.

v3->v4: rebased, added Andreas's realize patches on top

v2->v3: fix to s390 patch; added Reviewed-by and Cced patch 1 to
	qemu-stable.

v1->v2: remove useless pointer chasing in virtio_pci_notify, add
	patch 1 to fix breakage reported by Cornelia.

Andreas Färber (18):
  virtio-blk-dataplane: Improve error reporting
  virtio-9p: QOM realize preparations
  virtio-blk: QOM realize preparations
  virtio-serial: QOM realize preparations
  virtio-net: QOM realize preparations
  virtio-balloon: QOM realize preparations
  virtio-rng: QOM realize preparations
  virtio-scsi: QOM realize preparations
  virtio: Start converting VirtioDevice to QOM realize
  virtio-9p: Convert to QOM realize
  virtio-blk: Convert to QOM realize
  virtio-serial: Convert to QOM realize
  virtio-net: Convert to QOM realize
  virtio-balloon: Convert to QOM realize
  virtio-rng: Convert to QOM realize
  virtio-scsi: Convert to QOM realize
  virtio: Complete converting VirtioDevice to QOM realize
  virtio: Convert exit to unrealize

Paolo Bonzini (12):
  virtio-ccw: move virtio_ccw_stop_ioeventfd to virtio_ccw_busdev_unplug
  virtio-bus: remove vdev field
  virtio-ccw: remove vdev field
  virtio-pci: remove vdev field
  virtio-bus: cleanup plug/unplug interface
  virtio-blk: switch exit callback to VirtioDeviceClass
  virtio-serial: switch exit callback to VirtioDeviceClass
  virtio-net: switch exit callback to VirtioDeviceClass
  virtio-scsi: switch exit callback to VirtioDeviceClass
  virtio-balloon: switch exit callback to VirtioDeviceClass
  virtio-rng: switch exit callback to VirtioDeviceClass
  virtio-pci: add device_unplugged callback

 hw/9pfs/virtio-9p-device.c      |  43 +++++++-------
 hw/block/dataplane/virtio-blk.c |  30 +++++-----
 hw/block/dataplane/virtio-blk.h |   5 +-
 hw/block/virtio-blk.c           |  47 ++++++++++------
 hw/char/virtio-serial-bus.c     |  33 +++++------
 hw/net/virtio-net.c             |  36 ++++++------
 hw/s390x/virtio-ccw.c           |  83 +++++++++++++++------------
 hw/s390x/virtio-ccw.h           |   1 -
 hw/scsi/vhost-scsi.c            |  45 +++++++--------
 hw/scsi/virtio-scsi.c           |  57 +++++++++----------
 hw/virtio/virtio-balloon.c      |  32 +++++------
 hw/virtio/virtio-bus.c          |  80 +++++++++++++++-----------
 hw/virtio/virtio-mmio.c         |   9 +--
 hw/virtio/virtio-pci.c          | 122 ++++++++++++++++++++++++----------------
 hw/virtio/virtio-pci.h          |   1 -
 hw/virtio/virtio-rng.c          |  43 +++++++-------
 hw/virtio/virtio.c              |  40 ++++++++-----
 include/hw/virtio/virtio-bus.h  |  22 +++++---
 include/hw/virtio/virtio-rng.h  |   2 +
 include/hw/virtio/virtio-scsi.h |   4 +-
 include/hw/virtio/virtio.h      |   8 ++-
 tests/qdev-monitor-test.c       |   4 +-
 22 files changed, 413 insertions(+), 334 deletions(-)

-- 
1.8.3.1