Flexibility. This tool can do anything you may ever want to see in a virtualization environment.

Want to use a weird storage backend?

If it can't already use it, you can implement that yourself, no problem.

Want to use some pci(-e) devices inside the VM?

No problem. Review collected by and hosted on G2.com.

In some environments it requires quite a lot of configuration to get the desired performance, especially Disk I/O can sometimes be quite hard to get just right. Review collected by and hosted on G2.com.

We used Qemu to create a new device for the Microblaze architecture. A thorough read of the qemu source made hacking it a no brainer. We found the codebase very approachable, with plenty of examples ready to answer your questions. Really a great (and probably overkill) framework for our needs of simulating a low level device. Review collected by and hosted on G2.com.

Starting/stopping qemu can be a pain, depending on your workflow.

Qemu's docs at times seemed non-exsistant. It is really up to the user to read the portion of the codebase they need, and hack small tests to explore new ideas. Review collected by and hosted on G2.com.

It's Open source, it's free. One configuration will emulate many CPUs. Development can improve the software over time as it's opensource. It is highly configurable, like really configurable. Review collected by and hosted on G2.com.

It can be some times a pain to configure if you're new into the virtualization world, but there's a bunch of tutorials you can follow step by step on the internet and succeed. You can only virtualize using x86, x86_64, and PowerPC architectures. (Bye RPi) Review collected by and hosted on G2.com.

Virtualize every you wants with just two lines of shell script. Start a virtual environment without memory consumption or particular hardware requirements. Review collected by and hosted on G2.com.

A little bit more simple network configuration tool could be appreciated. Review collected by and hosted on G2.com.

Apart from Qemu being one of the most power full virtualisation tool, used in a wide range of cloud computing providers, it can also be used to emulate a different architecutre (e.g. you can run arm64 binaries/linux on you x86 machine). Review collected by and hosted on G2.com.

Difficult to set up the command line. The command line options differ significantly between different architectures (e.g. setting up a network interface is different in x86 and arm64) Review collected by and hosted on G2.com.

It's open source. The interface is very transparent, and you can tweak whatever you like. Review collected by and hosted on G2.com.

Doesn't work out of the box. Too many magic configuration options. I'm looking for a finished product, not the insides of an engine. Review collected by and hosted on G2.com.

Use different program from different CPU in the develop server which is X86. Review collected by and hosted on G2.com.

If I meet a crash or error in the QEMU, it not easy to identify the problem, find the root cause and fix the bug. Review collected by and hosted on G2.com.

Qemu can simulator different cpu ( arm/x86/ppc/mips) winin linux/windows/mac os. And simulate in different level as system mode simulation and user mode simulation. Review collected by and hosted on G2.com.

QEMU's interface is not very friendly to normal user. Review collected by and hosted on G2.com.

QEMU is an open-source software backed by some big names such as Google, IBM, RedHat and others. I enjoy it supports to execute on multiple processor architecture and operating systems. Review collected by and hosted on G2.com.

QEMU is extensively used but the available documentation is scarce and outdated. Review collected by and hosted on G2.com.