On Fri, Apr 29, 2022 at 08:30:33AM +0000, Sebastian Ene wrote:
> This driver creates per-cpu hrtimers which are required to do the
> periodic 'pet' operation. On a conventional watchdog-core driver, the
> userspace is responsible for delivering the 'pet' events by writing to
> the particular /dev/watchdogN node. In this case we require a strong
> thread affinity to be able to account for lost time on a per vCPU.
>
> This part of the driver is the 'frontend' which is reponsible for
> delivering the periodic 'pet' events, configuring the virtual peripheral
> and listening for cpu hotplug events. The other part of the driver
> handles the peripheral emulation and this part accounts for lost time by
> looking at the /proc/{}/task/{}/stat entries and is located here:
> https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3548817
>
> Signed-off-by: Sebastian Ene <sebastianene@xxxxxxxxxx>
> ---
> drivers/misc/Kconfig | 12 +++
> drivers/misc/Makefile | 1 +
> drivers/misc/vm-watchdog.c | 206 +++++++++++++++++++++++++++++++++++++
> 3 files changed, 219 insertions(+)
> create mode 100644 drivers/misc/vm-watchdog.c
>
> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index 2b9572a6d114..26c3a99e269c 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -493,6 +493,18 @@ config OPEN_DICE
>
> If unsure, say N.
>
> +config VM_WATCHDOG
> + tristate "Virtual Machine Watchdog"
> + select LOCKUP_DETECTOR
> + help
> + Detect CPU locks on the virtual machine. This driver relies on the
> + hrtimers which are CPU-binded to do the 'pet' operation. When a vCPU
> + has to do a 'pet', it exits the guest through MMIO write and the
> + backend driver takes into account the lost ticks for this particular
> + CPU.
> + To compile this driver as a module, choose M here: the
> + module will be called vm-wdt.
You forgot to name the module properly here based on the Makefile change
you made.
And again, as this is called a "watchdog", it seems crazy that it is not
in drivers/watchdog/
{sigh}
greg k-h
