On 2022-06-21 09:27, Greg Kroah-Hartman wrote:
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?
Not all architectures have KVM_GUEST, and arm64 has no use for it.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
