vfio/pci: Properly hide first-in-list PCIe extended capability
In the Linux kernel, the following vulnerability has been resolved: vfio/pci: Properly hide first-in-list PCIe extended capability There are cases where a PCIe extended capability should be hidden from the user. For example, an unknown capability (i.e., capability with ID greater than PCI_EXT_CAP_ID_MAX) or a capability that is intentionally chosen to be hidden from the user. Hiding a capability is done by virtualizing and modifying the 'Next Capability Offset' field of the previous capability so it points to the capability after the one that should be hidden. The special case where the first capability in the list should be hidden is han