"Virtualization hardware is unavailable" and "Virtualization hardware was detected but is disabled" when booting a RHEV Hypervisor.

Issue

Virtualization hardware was detected but is disabled.

After registering a RHEV Hypervisor in a RHEV 3.1 environment, during the subsequent reboot the following messages are reported on the console along with the login prompt;

Virtualization hardware is unavailable.
(Virtualization hardware was detected but is disabled)

Virtualization was configured in the BIOS.

The 'svm' and 'nx' cpu flags were set (this was an AMD machine);

# grep -E 'svm|nx' /proc/cpuinfo
flags       : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow rep_good extd_apicid pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy
flags       : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow rep_good extd_apicid pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy
flags       : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow rep_good extd_apicid pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy
flags       : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow rep_good extd_apicid pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy

The appropriate 'kvm' modules were loaded;

# lsmod | grep kvm
kvm_amd                41551  0 
kvm                   312245  1 kvm_amd