1.2. KVM Hypervisor Requirements

The KVM hypervisor requires:
  • an Intel processor with the Intel VT-x and Intel 64 virtualization extensions for x86-based systems; or
  • an AMD processor with the AMD-V and the AMD64 virtualization extensions.
Virtualization extensions (Intel VT-x or AMD-V) are required for full virtualization. Enter the following commands to determine whether your system has the hardware virtualization extensions, and that they are enabled.

Procedure 1.1. Verifying virtualization extensions

  1. Verify the CPU virtualization extensions are available

    enter the following command to verify the CPU virtualization extensions are available:
    $ grep -E 'svm|vmx' /proc/cpuinfo
  2. Analyze the output

    • The following example output contains a vmx entry, indicating an Intel processor with the Intel VT-x extension:
      flags   : fpu tsc msr pae mce cx8 vmx apic mtrr mca cmov pat pse36 clflush
      dts acpi mmx fxsr sse sse2 ss ht tm syscall lm constant_tsc pni monitor ds_cpl
      vmx est tm2 cx16 xtpr lahf_lm
      
    • The following example output contains an svm entry, indicating an AMD processor with the AMD-V extensions:
      flags   :  fpu tsc msr pae mce cx8 apic mtrr mca cmov pat pse36 clflush
      mmx fxsr sse sse2 ht syscall nx mmxext svm fxsr_opt lm 3dnowext 3dnow pni cx16
      lahf_lm cmp_legacy svm cr8legacy ts fid vid ttp tm stc
      
    If the grep -E 'svm|vmx' /proc/cpuinfo command returns any output, the processor contains the hardware virtualization extensions. In some circumstances, manufacturers disable the virtualization extensions in the BIOS. If the extensions do not appear, or full virtualization does not work, see Procedure A.4, “Enabling virtualization extensions in BIOS” for instructions on enabling the extensions in your BIOS configuration utility.
  3. Ensure the KVM kernel modules are loaded

    As an additional check, verify that the kvm modules are loaded in the kernel with the following command:
    # lsmod | grep kvm
    If the output includes kvm_intel or kvm_amd, the kvm hardware virtualization modules are loaded.

Note

The virsh utility (provided by the libvirt-client package) can output a full list of your system's virtualization capabilities with the following command:
# virsh capabilities