Qemu on Windows

Qemu can be used to run virtual guests on Windows.

Recommended binaries can be downloaded from: http://lassauge.free.fr/qemu/

  • i386 binary provides better performance on x64, if you are happy to run a 32-bit guest.
  • For basic machines the various selections of hardware devices generally don’t have significant impact on performance.
  • Poor VNC code in Qemu 2.5.0 heavily loads the cpu whenever clients are connected. This is fixed in Qemu 2.6.0.
  • Performance is completely useable & acceptable, but not exceptional.
  • To run in headless mode create a scheduled task that runs a batch file with the start string. Run the task as a network service user.
  • Configure SSH to administer the machine without needing to use VNC. Spice is unavailable in the Windows Qemu binaries.
  • The default network mode runs the network in the Windows users privilege space. It provides DHCP that assigns a 10.0.x.x address. It provides nat translation. ICMP Ping protocol does not work, but TCP & UDP work. Incoming port redirections can be provided in the start string.
  • For direct network connectivity the TAP driver can be installed from the OpenVPN installer. Bridge the created interface with the ethernet or wifi connections.

*A bug in Qemu 2.5 & 2.6 prevents use of vnc option “non-adaptive”, reporting the error: Invalid parameter ‘n-adaptive’

To work around this, use the string “nonon-adaptive”.