Comment # 9 on bug 1169174 from Joerg Roedel

(In reply to Borislav Petkov from comment #6)

> [    1.522731] pci 0000:00:00.2: AMD-Vi: Unable to read/write to IOMMU perf
> counter.

This message is harmless, it just means that there is no support for IOMMU
performance counters on this system. But the IOMMU is otherwise okay and can be
used.