When multiple devices share resources and one of them is to be passed
through to a guest, security of the entire system and of respective
guests individually cannot really be guaranteed without knowing
internals of any of the involved guests. Therefore such a configuration
cannot really be security-supported, yet making that explicit was so far
missing.
Resources the sharing of which is known to be problematic include, but
are not limited to
- - PCI Base Address Registers (BARs) of multiple devices mapping to the
same page (4k on x86),
- - INTx lines.
Common Attack Pattern Enumeration and Classification (CAPEC)
CAPEC-ID: CAPEC Description: The precise effects when shared resources are in use are system, device,
guest, and resource specific. None of privilege escalation, information
leaks, or Denial of Service (DoS) can be ruled out.