VM runs very slow using QEMU

Question

When I create a virtual machine using qemu-system-x86_64, it doesn't even boot up. This is how I boot the VM:

qemu-system-x86_64 -m 1024 -name mac -hda ~/Documents/ubuntu1

But when I create the same VM with Oracle VirtualBox or VMware Player, it runs fine.

What is the issue with QEMU, and how do I resolve it?

Solution

Be sure to add the -enable-kvm option to allow QEMU to use hardware virtualization capabilities (requires Intel VT-x or AMD AMD-V CPU extensions). Without those options, everything will be emulated in software (which is much slower). Example:

qemu-system-x86_64 -enable-kvm -m 1024 -name mac -hda ~/Documents/ubuntu1