vdev wdt-sp805

Emulate an SP805 watchdog

Synopsis:

vdev wdt-sp805 options

Options:

action [dump,]terminate|fiq

Specify what to do when the watchdog timer triggers:

  • dump – generate a guest dump, if the global option dump has been specified for the guest (see dump in this chapter, and Getting a guest dump in the Monitoring and Troubleshooting chapter)
  • fiq – send an edge on the interrupt line to which the device is connected
  • terminate – terminate the guest
frequency hz
The clock-cycle frequency that corresponds to the effective watchdog frequency as described in the SP805 specifications. This value is used to calculate the watchdog timeout. It is specified here in hertz (Hz).
If this option isn't specified, the configuration assumes the default: 25000000 (25 MHz).
intr intr
Specify the interrupt number on which to send an interrupt if the watchdog is configured to generate an interrupt.
loc addr
The base address of the registers in guest-physical memory. This value must be the same as the value specified for the guest wdtkick's -a option.
If this option isn't specified, the configuration assumes the default address: 0x1C0F0000.

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

Description:

ARM only. Provide a watchdog for guests running on ARM platforms.

Emulating the hardware SP805 watchdog device's behavior, the emulated SP805 watchdog device counts down twice before it triggers a SIGQUIT to terminate the hosting qvm process instance. Thus, if your watchdog period is set to three seconds, the effective watchdog clock period (when the SIGQUIT will be triggered) is six seconds.

Note: If the watchdog is configured to generate an interrupt, it is up to the guest to configure the interrupt controller to send the appropriate request to a vCPU.

For more information about how an SP805 watchdog calculates the effective watchdog clock period, see the SP805 specifications.

For more information about watchdogs in a QNX hypervisor system, see Watchdogs in the QNX Hypervisor for Safety chapter.