On Tue, Jun 21, 2022 at 08:03:09AM +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/vcpu_stall_detector.c | 222 +++++++++++++++++++++++++++++
> 3 files changed, 235 insertions(+)
> create mode 100644 drivers/misc/vcpu_stall_detector.c
>
> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index 41d2bb0ae23a..e15c85d74c4b 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -483,6 +483,18 @@ config OPEN_DICE
>
> If unsure, say N.
>
> +config VCPU_STALL_DETECTOR
> + tristate "VCPU stall detector"
> + select LOCKUP_DETECTOR
> + help
> + Detect CPU locks on a kvm 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 vcpu_stall_detector.
Should this depend on KVM_GUEST?
thanks,
greg k-h
