Watchdog with I6300ESB is supported for x86, for s390x I6300ESB is not supported and Diag288 is the supported watchdog device model

 Always reproducible - when we create a vm with Diag288 watchdog device model for s390x 

    1.Create a vm with below Diag288 watchdog config for s390x
 
apiVersion: kubevirt.io/v1
kind: VirtualMachine
metadata:
  name: vm-alpine
spec:
  running: true
  template:
    metadata:
      labels:
        kubevirt.io/domain: vm-alpine
    spec:
      domain:
        devices:
          watchdog:
            name: diag288-watchdog
            diag288:
              action: "poweroff"
          disks:
          - disk:
              bus: virtio
            name: containerdisk
          interfaces:
          - name: default
            masquerade: {}
        resources:
          requests:
            memory: 1Gi
      networks:
      - name: default
        pod: {}
      volumes:
      - containerDisk:
          image: quay.io/kubevirt/alpine-container-disk-demo:20241001_0a74910ea-s390x
        name: containerdisk

    2. Enable watchdog using below command
       "modprobe diag288_wdt" and verify /dev/watchdog is present in the vm
    3. Install watchdog on the VM using below command
       "yum install watchdog"
    4. Uncomment the following line in the /etc/watchdog.conf file and save     the changes
       watchdog-device = /dev/watchdog
    5. Enable the watchdog service to start on boot:
       systemctl enable --now watchdog.service
    6. Run one of the following commands to confirm the watchdog is active:
      pkill -9 watchdog  

 Getting below error for I6300ESB watchdog device model for s390x on virt-launcher container log:

 server error. command SyncVMI failed: "LibvirtError(Code=1, Domain=10, Message='internal error: QEMU unexpectedly closed the monitor (vm='default_rhel-8-scarlet-walrus-70'): 2025-01-31T07:57:04.087004Z qemu-kvm: -device {"driver":"i6300esb","id":"ua-i6300esb-watchdog","bus":"pci.0","addr":"0x1"}: 'i6300esb' is not a valid device model name')"

Watchdog will poweroff the vm and come out of vm console

    As watchdog device is not supported on s390x for 4.18.0(z) release, better we document the same in 4.18 documentation. This is being tracked in upstream kubevirt/kubevirt and we started working on the fix already here: https://github.com/kubevirt/kubevirt/issues/13826