KVM is not installed on this machine (/dev/kvm is missing)

Use the below command to check whether the KVM is installed in the machine or not,

kvm-ok 

Output:

INFO: /dev/kvm exists
KVM acceleration can be used

Output like the below means,

INFO: Your CPU does not support KVM extensions
KVM acceleration can NOT be used

In this scenario need to install KVM using the below command,

sudo apt-get install qemu-kvm libvirt-bin ubuntu-vm-builder bridge-utils

Hope this helps.

Either your CPU does not support virtualization, or it is disabled in the bios. Go into your bios and see if you can find a setting to enable it.

HP-EliteBook-820-G1:/opt/android-studio/bin$ sudo /usr/sbin/kvm-ok
INFO: /dev/kvm does not exist
HINT:   sudo modprobe kvm_intel
INFO: Your CPU supports KVM extensions
INFO: KVM (vmx) is disabled by your BIOS
HINT: Enter your BIOS setup and enable Virtualization Technology (VT),
      and then hard poweroff/poweron your system
KVM acceleration can NOT be used

Affter bios setting, I used the following command

sudo modprobe kvm_intel

Now is ok