Monday 19 December 2016

Issue where KVM guest freezes just before installation of CentOS 7

I've been playing around with KVM on CentOS 7 in preparation for the RHCE exam. I was experiencing an issue where the guest virtual machine would freeze just before attempting an install (again, CentOS 7 as the guest).

The testing machine is quite old (has an Intel Core 2 6400 CPU) but it hasn't shown any other symptoms of hardware issues.

The logs didn't appear to show anything of interest other than some debugging information which is apparently normal:
[20389.379023] kvm [19537]: vcpu0 unhandled rdmsr: 0x60d
[20389.379034] kvm [19537]: vcpu0 unhandled rdmsr: 0x3f8
[20389.379039] kvm [19537]: vcpu0 unhandled rdmsr: 0x3f9
[20389.379043] kvm [19537]: vcpu0 unhandled rdmsr: 0x3fa
[20389.379048] kvm [19537]: vcpu0 unhandled rdmsr: 0x630
[20389.379053] kvm [19537]: vcpu0 unhandled rdmsr: 0x631
[20389.379057] kvm [19537]: vcpu0 unhandled rdmsr: 0x632

Anyway, I was able to work around the issue by feeding the "--cpu host" option to virt-install, or by ticking "Copy host CPU configuration" under the CPUs tab of the VM configuration.

Hope this helps save someone else some time!