A note about nomenclature

Terminology

Please note the following about the terminology used in this guide:

device

We use device to mean a hardware device that exists as a physical component on the system. Contrast vdev.

guest

A guest is a guest OS and any applications that are running on this OS; a qvm process instance (see below) hosts a guest. The guest runs in a VM (see below) created by the qvm process.

If we need to distinguish between the guest OS and the applications, we spell it out (e.g., To stop an application without stopping the guest OS ...).

host

In most cases, the term host refers not to a host computer (the desktop or laptop, which you can connect to your target system to load a new image or debug) but to the hypervisor or something in the hypervisor (e.g., The CPU instructs the guest thread to exit guest mode and continue in host mode).

When the context doesn't make the meaning of host clear, we'll use development host to refer to the desktop or laptop, and host domain or hypervisor host to indicate the hypervisor and all of its components.

When discussing privilege or exception levels, we'll use hypervisor host or hypervisor host domain (e.g., Processes running in the hypervisor host domain sometimes run at EL2 on ARM boards, or at VMX root mode on x86 boards).

hypervisor

A software system consisting of a QNX OS microkernel that has its hypervisor host mode enabled and can include one or more virtual machines.

There are two products from QNX that you can use to create hypervisor systems: the non-safety QNX Hypervisor (QH) and the safety-certified QNX Hypervisor for Safety (QHS). For simplicity, we use the terms QNX hypervisor or hypervisor when describing design and implementation details that apply to both the QH and QHS variants.

qvm

A qvm (or qvm process instance) is a process in the hypervisor that hosts a guest.

The hypervisor starts qvm process instances; each qvm process instance presents a virtual machine (VM) in which a guest can run.

A qvm process runs at times at the permission level of the hypervisor host domain (it is part of the hypervisor) and at times at the lower privilege level of the guest it is hosting.

vdev

We use virtual device (or vdev) to mean any device that the hypervisor virtualizes in some way (see Virtual devices in this chapter). Examples of vdevs include an interrupt controller (virtualized), or an Ethernet device controller (para-virtualized).

If we ever refer to a virtual device simply as a device, that is confusing and an error, so let us know about it.

VM

A virtual machine (or VM) is presented by a qvm process instance to a guest, which runs in the VM; the VM hosts the guest.

Filenames

We use the following nomenclature to name the files in a QNX virtualized environment:

Prefixes

Prefixes identify where a file is used:

hypervisor

The file includes or is used to build and/or configure the hypervisor host domain. The prefix is followed by a release number.

vdev-

The file is a virtual device.

Suffixes

Suffixes identify the type of file:

.build

The file is a buildfile, for the QNX hypervisor host domain, or for a QNX guest.

For Linux and other non-QNX guests, see the documentation for those types of OSs.

.img

The file is a bootable image. This image may include only the hypervisor host domain, only a guest, or the host domain and one or more guests.

.qvmconf

The file is a configuration file for a VM; it is parsed by a qvm process instance to assemble the VM.

Examples