CVE-2023-46839

PCI devices can make use of a functionality called phantom functions, that
when enabled allows the device to generate requests using the IDs of
functions that are otherwise unpopulated. This allows a device to extend
the number of outstanding requests. Such phantom functions need an IOMMU
context setup, but failure to setup the context is not fatal when the
device is assigned. Not failing device assignment when such failure happens
can lead to the primary device being assigned to a guest, while some of the
phantom functions are assigned to a different domain.

Notes