A host cannot recognize a GPU device. What should I do?

Symptom

The host cannot recognize the GPU device, and the IOMMU readiness status shows Unavailable.

Cause

The host was not restarted after IOMMU was enabled.

Solution

1. Migrate all virtual machines on the host to other hosts.

2. Go to Resource Center > Hosts and VMs to open the Hosts interface. Select the host and click Actions > Enter Maintenance Mode.

3. Log in to the host and run the following commands to restart it:

   # Confirm no VMs are running on the host
   [root@localhost ~]# virsh list
   [root@localhost ~]# sync;sync;reboot