[CentOS] KVM does not start anymore

Hi,

I had a C7 virtual machine running on a C7 host for several weeks without
any problems.
Today I rebootet the host and now the virtual machine does not start
anymore.

I can see grub coming up and starting the kernel. After some seconds the
last thing that is visble on the VM console is "ss perfctr msr (MSR c1
is0)" then the screen goes blank with just a blinking cursor in the upper
left corner. After that nothing happens anymore. The CPU load on the host
is nearly 0%.

Any ideas what could be the reason and how to solve this?

Best regards,
Bernd