Eric Farman a15ac665b9 vfio-mdev: Wire in a request handler for mdev parent ... While performing some destructive tests with vfio-ccw, where the paths to a device are forcible removed and thus the device itself is unreachable, it is rather easy to end up in an endless loop in vfio_del_group_dev() due to the lack of a request callback for the associated device. In this example, one MDEV (77c) is used by a guest, while another (77b) is not. The symptom is that the iommu is detached from the mdev for 77b, but not 77c, until that guest is shutdown: [ 238.794867] vfio_ccw 0.0.077b: MDEV: Unregistering [ 238.794996] vfio_mdev 11f2d2bc-4083-431d-a023-eff72715c4f0: Removing from iommu group 2 [ 238.795001] vfio_mdev 11f2d2bc-4083-431d-a023-eff72715c4f0: MDEV: detaching iommu [ 238.795036] vfio_ccw 0.0.077c: MDEV: Unregistering ...silence... Let's wire in the request call back to the mdev device, so that a device being physically removed from the host can be (gracefully?) handled by the parent device at the time the device is removed. Add a message when registering the device if a driver doesn't provide this callback, so a clue is given that this same loop may be encountered in a similar situation, and a message when this occurs instead of the awkward silence noted above. Signed-off-by: Eric Farman <farman@linux.ibm.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>		2020-12-03 16:21:07 -07:00
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Kconfig
Makefile
mdev_core.c	vfio-mdev: Wire in a request handler for mdev parent	2020-12-03 16:21:07 -07:00
mdev_driver.c
mdev_private.h
mdev_sysfs.c
vfio_mdev.c	vfio-mdev: Wire in a request handler for mdev parent	2020-12-03 16:21:07 -07:00