I have a Tesla P4 installed on a HPE ProLiant DL360 Gen10 on a CentOS 7.7. The setup was running fine since at least February. I made a successful upgrade from oVirt 4.2 to 4.3 and CentOS 7.6 to CentOS 7.7. I was using in oVirt in a pass-througth setting.

I made a minor upgrade a few days ago. And since the VM is unable to see the Tesla P4. I think that the main problem is with mdev. vdsm-client Host hostdevListByCaps | grep mdev return nothing. There is no directory /sys/class/mdev_bus. I tried a full modload: modprobe nvidia_vgpu_vfio nvidia vfio_mdev mdev vfio_iommu_type1 vfio nvidia nvidia-modeset nvidia-drm nvidia-uvm vfio-pci. But it does nothing.

Why did my kernel think the P4 is not mdev-compatible any more ? How can I check that ? I think it break when upgrading my kernel from kernel-3.10.0-1062.1.2.el7.x86_64 to kernel-3.10.0-1062.4.1.el7.x86_64.

I tried with both the nouveau driver and the nvidia driver.