[Qemu-devel] [PATCH 0/2] pci: exit path cleanup and fix

[Alex Williamson <alex.williamson@redhat.com>]

We've currently got a bug in pci_unregister_device in the ordering of
calling the driver exit function and unregistering io regions.  In
every driver memory regions are created in the init function and
destroyed in the exit function.  By calling pci_unregister_io_regions
after the exit function, we're calling memory_region_del_subregion
with a pointer to a MemoryRegion that has already been destroyed.

It's easy enough to change the ordering, but the exit function is
currently allowed to fail.  Even if we wanted to restore the device
at that point, we've interrupted the mappings from the guest
perspective and it seems precarious at best whether an exit function
can fail and leave a usable device.  Fortunately nobody has any
possibility of actually failing the exit path.  Normally I'm a
proponent of error paths, but allowing an exit to fail is like
allowing free(3) to fail.

So, firt redefine that exit can't fail, then fix the ordering of
pci_unregister_device().  If anyone has plans for a failure case in
the exit path, please speak now.  Thanks,

Alex

---

Alex Williamson (2):
      pci: Unregister BARs before device exit
      pci: convert PCIUnregisterFunc to void


 hw/ac97.c               |    3 +--
 hw/e1000.c              |    3 +--
 hw/eepro100.c           |    3 +--
 hw/es1370.c             |    3 +--
 hw/ide/cmd646.c         |    4 +---
 hw/ide/ich.c            |    4 +---
 hw/ide/piix.c           |    4 +---
 hw/ide/via.c            |    4 +---
 hw/intel-hda.c          |    3 +--
 hw/ioh3420.c            |    8 +++-----
 hw/ivshmem.c            |    4 +---
 hw/lsi53c895a.c         |    4 +---
 hw/ne2000.c             |    3 +--
 hw/pci.c                |   11 +++++------
 hw/pci.h                |    2 +-
 hw/pci_bridge.c         |    3 +--
 hw/pci_bridge.h         |    2 +-
 hw/pci_bridge_dev.c     |   12 ++++--------
 hw/pcnet-pci.c          |    3 +--
 hw/rtl8139.c            |    3 +--
 hw/usb/hcd-uhci.c       |    3 +--
 hw/virtio-pci.c         |   23 +++++++++++------------
 hw/wdt_i6300esb.c       |    4 +---
 hw/xio3130_downstream.c |    8 +++-----
 hw/xio3130_upstream.c   |    8 +++-----
 25 files changed, 48 insertions(+), 84 deletions(-)