A Xen guest reaches the host through several interfaces, each an escape surface with a different impact. Hypercalls enter the hypervisor directly; grant tables and event channels mediate shared memory with dom0; paravirtualized guests talk to backend drivers in dom0. HVM guests additionally use a QEMU device-model process, inheriting the QEMU device surface.
Subtopics#
- Hypercalls: the direct guest-to-hypervisor interface.
- Grant tables and event channels: shared memory and signalling with dom0.
- PV backend drivers: blkback and netback in dom0.