KVM "cpu0 unimplemented perfctr wrmsr: 0x186 data 0x130079" messages are seen in logs

Guys,

Usally I look into /var/log/messages file for troubleshooting issues and I have noticed below messages in my fedora 14 system logs. I was discarding it as I know it is harmless, but today I thought of blogging it because so many are worried about it.

Nov19 13:27:02 humbles-lap kernel: [903605.793414] kvm: 1541: cpu0 unhandled wrmsr: 0x198 data 0
Nov19 13:27:12 humbles-lap kernel: [903615.462839] kvm: 1541: cpu0 unimplemented perfctr wrmsr: 0x186 data 0x130079
Nov19 13:27:12 humbles-lap kernel: [903615.462843] kvm: 1541: cpu0 unimplemented perfctr wrmsr: 0xc1 data 0xffdb7956
Nov19 13:27:12 humbles-lap kernel: [903615.462849] kvm: 1541: cpu0 unimplemented perfctr wrmsr: 0x186 data 0x530079

These messages can be ignored. These messages are spit to logs when operating system executes a probe to know whether PMU is available on the P6 processor.

[root@humbles-lap images]# cat /proc/cpuinfo |grep -i family
cpu family : 6
cpu family : 6
cpu family : 6
cpu family : 6
[root@humbles-lap images]#

That said, with cpu family 6 ( P6) processors , PMU support is not specified via CPUID leaf 0xa, so the messages comes as a reply to kernel probe. Dont worry about these as it is kept for debugging purpose.