According to Microsoft in a new fast publish article:
If you are using Linux Integration Services in a Linux Virtual Machine running on Hyper-V Server 2008 or Hyper-V Server 2012, you should enable Advanced Programmable Interrupt Controller (APIC) support in the Virtual Machine.
This APIC setting is configured in the guest OS. Some Googling reveals that some are disabling this setting using “noapic”.
APIC support is required for proper functioning of all versions of Linux Integration Services. If APIC support is disabled by specifying "noapic" in the Linux Virtual Machine’s boot options, then the Virtual Machine may fail to boot after installation of Linux Integration Services.