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QNX Hypervisor User's Guide
This User's Guide explains the QNX hypervisor architecture and provides instructions for installing and running a QNX Hypervisor system, changing system components and configuration, and using hypervisor features such as virtual devices (vdevs).
Virtual Device Reference
This chapter presents the virtual devices (vdevs) delivered with QNX hypervisors, and describes how to configure these vdevs.
vdev timer8254
Emulate the Intel 8254 timer chip

QNX Momentics IDE User's Guide
This User's Guide describes version 8.0 of the Integrated Development Environment (IDE) that's part of the QNX Tool Suite.
QNX Software Development Platform
QNX SDP is a cross-compiling and debugging environment, including an IDE and command-line tools, for building binary images and programs for target boards running the QNX OS 8.0.
QNX Software in the Cloud
QNX Software in the Cloud enables developers to use the QNX OS in the Amazon cloud environment.
QNX Toolkit for Visual Studio Code
This User's Guide describes the QNX^® Toolkit for Visual Studio Code. The guide introduces you to the QNX Toolkit by explaining the QNX development environment and how to build, run, and debug your QNX^® Operating System (OS) applications and systems.
QNX Hypervisor User's Guide
This User's Guide explains the QNX hypervisor architecture and provides instructions for installing and running a QNX Hypervisor system, changing system components and configuration, and using hypervisor features such as virtual devices (vdevs).
- Understanding QNX Virtual Environments
  QNX hypervisors are designed to meet the expectations of a hypervisor specified by the Popek/Goldberg Theorem.
- QNX Hypervisor: Protection Features
  This chapter explains the main features used by the QNX Hypervisor to protect itself and its guests. Many of these features are part of the design, while others are configurable.
- Configuration
  A QNX hypervisor, its qvm processes that create the VMs in which guests run, and these guests must be configured to work together.
- Building a QNX Hypervisor System
  This chapter explains how to build (assemble) a QNX Hypervisor system and transfer a bootable image to a supported target platform.
- Booting and Shutting Down
  This chapter describes how to boot and shut down the hypervisor host and guests in a QNX hypervisor system.
- Using Virtual Devices, Networking, and Memory Sharing
  This chapter describes how guests can discover and connect to vdevs and how they can use important hypervisor capabilities, such as networking and memory sharing.
- Monitoring and Troubleshooting
  This chapter describes some tools and techniques you can use to monitor and troubleshoot your hypervisor system.
- Performance Tuning
  This chapter describes common sources of overhead in a QNX hypervisor system, and strategies for reducing this overhead and optimizing system performance.
- VM Configuration Reference
  When you specify options to configure a qvm process, you are assembling and configuring the components of a virtual machine (VM) in which a guest will run.
- Virtual Device Reference
  This chapter presents the virtual devices (vdevs) delivered with QNX hypervisors, and describes how to configure these vdevs.
  - Common vdev options
    There are common options that apply to more than one type of vdev.
  - vdev 8259
    Emulate minimal functionality of an Intel 8259 PIC
  - vdev gic
    Emulate an ARM standard Generic Interrupt Controller
  - vdev hpet
    Provide the guest with an HPET device
  - vdev ioapic
    Emulate an Intel ioapic PIC
  - vdev mc146818
    Emulate the Motorola 146818 real-time clock chip
  - vdev pci-dummy
    Provide a read-only, inactive PCI device
  - vdev pci-host-bridge
    Create a PCI host bridge device
  - vdev pckeyboard
    Emulate an IBM PC keyboard controller
  - vdev pl011
    Emulate a PL011 serial device
  - vdev progress
    Report when a guest accesses an address in guest-physical memory, or attempts to execute specific instructions
  - vdev ser8250
    Emulate the Intel 8250 UART
  - vdev shmem
    Provide an inter-guest system shared memory device
  - vdev smmu
    Provide the required subset of smmu-*.so library functionality needed by a smmuman service running in a QNX guest
  - vdev timer8254
    Emulate the Intel 8254 timer chip
  - vdev virtio-blk
    Provide the standard VIRTIO interface for block devices
  - vdev virtio-console
    Provide the standard VIRTIO interface for console devices
  - vdev virtio-entropy
    Provide a guest with a source of random numbers (entropy)
  - vdev virtio-net
    Provide the standard VIRTIO interface for network devices
  - vdev wdt-ib700
    Emulate the watchdog found on the IB700 board
  - vdev wdt-sp805
    Emulate an SP805 watchdog
- Virtual Machine Firmware
  The virtual machines (VMs) in a QNX Hypervisor system provide a comprehensive firmware interface for guest OSs to manage VM power settings, access timers, and more.
- Utilities and Drivers Reference
  This chapter describes the utilities and drivers delivered with the QNX hypervisor.
- Terminology
  The following terms are used throughout the QNX hypervisor documentation.
Typographical Conventions, Support, and Licensing
This section describes the typographical conventions used throughout the documentation, explains how to obtain technical support, and provides some information about licensing.

vdev timer8254

Emulate the Intel 8254 timer chip

Synopsis:

vdev timer8254 options

Options:

frequency input_freq_in_hz: Set the input frequency to the device, in Hertz.
intr intr: Signal intr when a timer expires.
loc addr: Set the base address of the device registers to addr (default space is io:).

For a list of options available to all vdevs, see Common vdev options at the beginning of this chapter.

Description:

x86 only. The timer8254 vdev emulates the Intel 8254 timer chip.

Page updated: August 11, 2025