What are the differences between QEMU and VirtualBox?

Question

Recently, I found out that there is the QEMU project. I've used VirtualBox before, and I know about Xen and VMWare.

What are the differences between QEMU and VirtualBox? Should I stick with VirtualBox?
In which cases is QEMU better?

Solution 1

Basically both have features which the other does not have, so this might ease the decision. QEMU/KVM is better integrated in Linux, has a smaller footprint and should therefore be faster.

VirtualBox is a virtualization software limited to x86 and amd64 architecture. Xen uses QEMU for the hardware assisted virtualization, but can also paravirtualize guests without hardware virtualisation. QEMU supports a wide range of hardware and can make use of the KVM when running a target architecture which is the same as the host architecture.

Xen is a Type-1 hypervisor where VirtualBox and QEMU are considered as Type-2 hypervisors (also there might be a debate considering kvm being a kernel module).

A similar question has been asked before in this community.

Solution 2

QEMU with KVM is much, much faster than VirtualBox, you can test it yourself:

VirtualBox:

QEMU

Disk and CPU tests provided similar results, more or less.

Solution 3

A difference is the supported list of instructions. Virtualbox and VMware don't support the f16c-instructions supported by architectures beginning with Ivy Bridge, which limits compilations even with newer CPUs to those for Sandy Bridge and leads to other incompatibilities.

Comments

[JesseBoyd]

is QEMU as safe as virtualbox for sandboxing Windows? I don't want windows to have any access to my Linux OS

[baptx]

@JesseBoyd they both had security vulnerabilities allowing virtual machine escape: en.wikipedia.org/wiki/Virtual_machine_escape

[teknoraver]

@ben In the next kernel KVM will not be a kernel module anymore :)

[Some Name]

@teknoraver What will it be then? I'm using 5.6.8 am I affected?

[ben]

@teknoraver please state your source

[Hilton Fernandes]

That's interesting. A Web page suggest otherwise: techgenix.com/qemu-vs-virtualbox