v2: * Added received acks and reviews, thanks! * Rebased and resolved conflict in patch 2/, dropped reviews due to changes and added Alexey to cc as spapr code is moved too * Added stable tag for patches 1-3 * Resolved comment typo Eric noted in patch 1 * Split AMBA out to patches 8 & 9 as Eric noted amba_bustype is not exported. These can be separate follow-up patches if delayed
Please re-ack/review patch 2. Eric, I'm happy to add your Tested-by to the whole series if appropriate as well. Thanks, Alex v1: VM hotplug testing reveals a number of races in the vfio device, group, container shutdown path, some attributed to libvirt's ask/take unplug behavior and some long standing with groups potentially composed of multiple devices, where each device can be independently bound to drivers. Libvirt's ask/take behavior is a result of the asynchronous nature of PCI hotplug, libvirt registers a hot-unplug request (ask), which is acknowledged almost immediately and then proceeds to try to unbind the device from the vfio bus driver (take). This sets us off on racing paths where we allow the device to be released from the group much like would happen in groups with multiple devices, while the group and container are torn down separately. These races are addressed in the first 3 patches of this series. The long standing issue with removing devices from in-use groups is that we feel that the system is compromised if we allow user and host devices within the same non-isolated group. This triggers a BUG_ON when we detect this condition after the rogue driver binding. Since that code was put in place we've added driver_override support for all of the physical buses supported by vfio, giving us a way to block binding to such compromising drivers. We finally enable that in the latter 4 patches of this series, minding that we need to allow re-binding to non-compromising drivers, and also noting that a small synchronization stall is effective in eliminating the need for this blocking in the more common singleton device group case. Reviews, comments, and acks appreciated. Thanks, Alex --- Alex Williamson (9): vfio: Fix group release deadlock kvm-vfio: Decouple only when we match a group vfio: New external user group/file match iommu: Add driver-not-bound notification vfio: Create interface for vfio bus drivers to register vfio: Register pci, platform, amba, and mdev bus drivers vfio: Use driver_override to avert binding to compromising drivers amba: Export amba_bustype vfio: Add AMBA driver_override support drivers/amba/bus.c | 1 drivers/iommu/iommu.c | 3 drivers/vfio/mdev/vfio_mdev.c | 13 ++ drivers/vfio/pci/vfio_pci.c | 7 + drivers/vfio/platform/vfio_amba.c | 24 +++ drivers/vfio/platform/vfio_platform.c | 24 +++ drivers/vfio/vfio.c | 252 ++++++++++++++++++++++++++++++++- include/linux/iommu.h | 1 include/linux/vfio.h | 5 + virt/kvm/vfio.c | 39 +++-- 10 files changed, 343 insertions(+), 26 deletions(-)