Cargo Features

VhostUserBackend has no features set by default.

[dependencies]
vhost-user-backend = { version = "0.15.0", features = ["xen", "postcopy"] }
xen

Enables xen of vhost and vm-memory

postcopy = userfaultfd

Enables postcopy of vhost

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features. These features may have been created by mistake, and this functionality may be removed in the future.

userfaultfd postcopy?