[v5,0/3] vfio/pci: Check the device set open count on reset

Message

Anthony DeRossi Nov. 5, 2022, 10:44 p.m. UTC

This series fixes an issue where devices bound to vfio-pci are not reset when
they are released. Skipping the reset has unpredictable results depending on
the device, and can cause errors when accessing the device later or binding to
a different driver.

This revision replaces the patch that introduced an open_count field in
vfio_device_set with one that exports a new function that can be used for the
same purpose, i.e., determining whether any device in the set is in use.

The first patch in this series fixes a life cycle issue that was discovered in
an earlier revision of the series.

Anthony

v4 -> v5:
- Replaced patch 2 with a patch that introduces a new function to get the
  open count of a device set
- Updated patch 3 to use the new function
v4: https://lore.kernel.org/kvm/[e-mail]/

v3 -> v4:
- Added a patch to fix device registration life cycle
- Added a patch to add a public open_count on vfio_device_set
- Changed the implementation to avoid private open_count usage
v3: https://lore.kernel.org/kvm/[e-mail]/

v2 -> v3:
- Added WARN_ON()
- Revised commit message
v2: https://lore.kernel.org/kvm/[e-mail]/

v1 -> v2:
- Changed reset behavior instead of open_count ordering
- Retitled from "vfio: Decrement open_count before close_device()"
v1: https://lore.kernel.org/kvm/[e-mail]/

Anthony DeRossi (3):
  vfio: Fix container device registration life cycle
  vfio: Export the device set open count
  vfio/pci: Check the device set open count on reset

 drivers/vfio/pci/vfio_pci_core.c | 10 +++++-----
 drivers/vfio/vfio_main.c         | 24 +++++++++++++++++++-----
 include/linux/vfio.h             |  1 +
 3 files changed, 25 insertions(+), 10 deletions(-)