[PATCH 0/6] VIRTIO-IOMMU/VFIO: Revert IOMMUDevice clear and fix hotunplug

[Eric Auger]

1b889d6e39c3 ("virtio-iommu: Clear IOMMUDevice when VFIO
device is unplugged" fixes the VFIO hotplug/hotunplug/hotplug
sequence by clearing the IOMMUDevice which backs the VFIO device.
However this brings other troubles such as a memory corruption.

Even when fixing some cleanups that were missed on the first
attempt the memory corruption still exists if the IOMMUDevice is
freed. Until we understand the exact cause let's make things simpler:
let the backing IOMMUDevice survive the unplug as what is done
on intel iommu for instance. Clean up/reset resources that would
prevent the device from being hotplugged again (probe_done is removed,
[host_]resv_regions are reset). By doing this we also rule out the
use case of aliased BDFs which is known to be not functional with
virtio-iommu (missing guest kernel support) and the virtio-iommu device
implementation is not ready either.

This series can be found at:
https://github.com/eauger/qemu/tree/virtio_iommu_device_clear_fixes_v1


Eric Auger (6):
  Revert "virtio-iommu: Clear IOMMUDevice when VFIO device is unplugged"
  virtio-iommu: Remove probe_done
  virtio-iommu: Free [host_]resv_ranges on unset_iommu_devices
  virtio-iommu: Remove the end point on detach
  hw/vfio/common: Add vfio_listener_region_del_iommu trace event
  virtio-iommu: Add trace point on
    virtio_iommu_detach_endpoint_from_domain

 include/hw/virtio/virtio-iommu.h |  1 -
 hw/vfio/common.c                 |  3 +-
 hw/virtio/virtio-iommu.c         | 88 +++++++++++---------------------
 hw/vfio/trace-events             |  3 +-
 hw/virtio/trace-events           |  1 +
 5 files changed, 35 insertions(+), 61 deletions(-)

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2.41.0