The current documentation https://docs.redhat.com/en/documentation/openshift_container_platform/4.19/html-single/virtualization/index#virt-adding-kernel-arguments-enable-IOMMU_virt-configuring-pci-passthrough is missing verification step to confirm if IOMMU is enabled from the OS perspective

Customer reported that their Cisco management software can disable IOMMU in the BIOS by default, leading to issues with IOMMU-dependent features like device passthrough.

Suggestion was made to add verification step in the documentation to confirm if IOMMU is enabled as OS level.

Proposed Action: 
-----------------

Please add a verification step to the documentation that instructs users to run # ls -l /sys/kernel/iommu_groups and explains the expected output for enabled/disabled IOMMU. This will help users diagnose IOMMU configuration issues early and improve the overall user experience. 

Output: IOMMU is not enabled/working:

[root@xxx~]# ls -l /sys/kernel/iommu_groups
total 0

Output: IOMMU is working:

[root@xxx]# ls -l /sys/kernel/iommu_groupstotal 
total 0
drwxr-xr-x. 3 root root 0 Jul  2 23:06 xx
drwxr-xr-x. 3 root root 0 Jul  2 23:06 xx
drwxr-xr-x. 3 root root 0 Jul  2 23:06 xx
drwxr-xr-x. 3 root root 0 Jul  2 23:06 xx
drwxr-xr-x. 3 root root 0 Jul  2 23:06 xx

...
...
...

4.19

100%

Refer:  https://docs.redhat.com/en/documentation/openshift_container_platform/4.19/html-single/virtualization/index#virt-adding-kernel-arguments-enable-IOMMU_virt-configuring-pci-passthrough 

The missing verification step to confirm if IOMMU is enabled. 

Verification step should be present in the documentation.