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QNX Hypervisor
The QNX Hypervisor allows you to run multiple OSs on a target system so you can separate critical and non-critical functions, support a wide variety of applications, and reduce hardware costs.
QNX Hypervisor for Safety Virtual Device Developer's API Reference
guest.h
Definitions for manipulating a guest system
guest_clock_start()
Make the current thread start contributing to the guest's time flow

QNX Momentics IDE User's Guide
This User's Guide describes version 7.1 of the Integrated Development Environment (IDE) that's part of the QNX Momentics 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 QNX Neutrino 7.1.
QNX Hypervisor
The QNX Hypervisor allows you to run multiple OSs on a target system so you can separate critical and non-critical functions, support a wide variety of applications, and reduce hardware costs.
- QNX Hypervisor for Safety User's Guide
- QNX Hypervisor for Safety Virtual Device Developer's Guide
- QNX Hypervisor for Safety Virtual Device Developer's API Reference
  - Function Safety
    This section provides an overview of the restrictions that may apply when using the functions in this API.
  - aarch64/vmid.h
    Definitions to access a guest's VMID (ARM)
  - abi.h
    Application binary interface (ABI) version of the vdev API
  - cdev.h
    Functions to create virtual character devices for guests
  - firmware.h
    Functions for working with the firmware components of the VM presented to the guest
  - gasp.h
    Functions for working in guest address spaces
  - guest.h
    Definitions for manipulating a guest system
    - Guest termination reasons
      System-assigned and custom identifiers that describe why the guest terminated
    - guest_button_register()
      Register a callback when the specified button event is generated
    - guest_button_type
      Console buttons, inspired by the ACPI specification
    - guest_clock_start()
      Make the current thread start contributing to the guest's time flow
    - guest_clock_stop()
      Make the current thread stop contributing to the guest's time flow
    - guest_cpu_read()
      Read data from a vCPU
    - guest_cpu_write()
      Write data into a specified vCPU
    - guest_instr_callback_func_t
      Callback function prototype for handling special guest instructions
    - guest_instr_register()
      Register a callback function to invoke when the guest executes a special instruction
    - guest_instr_type
      Guest instructions for which you can get a callback
    - guest_intr_assign()
      Assign a source to an interrupt
    - guest_intr_level()
      Return a global number for an interrupt line
    - guest_intr_notify()
      Inform the qvm process that the guest has unmasked or acknowledged a virtual interrupt
    - guest_intr_num_pins()
      Specify the size of the PIC vdev pin information array
    - guest_intr_signal()
      Assert or de-assert an interrupt request to a PIC or guest CPU
    - guest_intr_string()
      Convert a guest interrupt to a string representation
    - guest_memory_filter_kind
      Kinds of memory operations that can be filtered
    - guest_msi_deliver_func_t
      Function prototype for the callback to deliver a Message Signaled Interrupt (MSI)
    - guest_msi_register()
      Register a PIC MSI handle
    - guest_msi_signal()
      Send an MSI to a guest
    - guest_power_state_callback_func_t
      Function prototype for power state callback
    - guest_power_state_cmd
      Guest system CPU power state flags
    - guest_power_state_current()
      Return the current power state of the guest system
    - guest_power_state_notify_create()
      Create a structure to hold a power state change callback
    - guest_power_state_notify_delete()
      Remove a power state notification structure
    - guest_power_state_notify_register()
      Set the characteristics of a power state notification structure
    - guest_register_memory_filter()
      Register a guest memory filter
    - guest_terminate()
      Terminate the execution of a guest
    - guest_termination_cause_t
      Causes of guest termination
    - guest_timer_create()
      Create a guest system timer
    - guest_timer_data
      Structure for timer information
    - guest_timer_notify()
      Request notification when the specified number of clock cycles have elapsed in the guest
    - guest_timer_state()
      Get state information for a guest timer
    - guest_write_all_ones()
      Write a series of ones to a vCPU (e.g., for a 32-bit target: FFFF FFFF)
    - guest_write_core_file()
      Write out the guest core file
    - guest_xfer_flags
      Flags for the state read and write requests
  - hpci.h
    Host PCI interface for vdevs
  - hw_pci.h
    PCI support for vdevs
  - outpipe.h
    Definitions for the output pipe (outpipe)
  - types.h
    vdev API base types
  - utils.h
    Miscellaneous utility functions
  - vdev.h
    Source compatibility header file
  - vdev-core.h
    Definitions for vdevs
  - vio.h
    Definitions for VIRTIO vdevs
  - vpci.h
    Definitions for virtual PCI devices
  - wdog.h
    Definitions to support virtual watchdog devices
  - x86_64/apic.h
    Definitions for the virtual APIC bus (x86)
- QNX Hypervisor User's Guide
QNX Software in the Cloud
QNX Software in the Cloud enables developers to use the QNX software in Amazon Web Services (AWS) and Microsoft Azure (Azure).
QNX Advanced Virtualization Frameworks User's Guide
This User's Guide is aimed at all systems integrators and developers who want to design and build embedded systems using the QNX Advanced Virtualization Frameworks.
Typographical Conventions, Support, and Licensing
This section describes the typographical conventions used throughout the documentation and explains how to obtain technical support.

guest_clock_start()

Make the current thread start contributing to the guest's time flow

Synopsis:

#include <qvm/guest.h>

void guest_clock_start(struct guest_system *gsp)

Arguments:

gsp: A pointer to the guest system.

Description:

Use this function to make the current thread start contributing to the advancement of timers in the guest.

Page updated: March 12, 2026