QEMU emulates a PCI UHCI USB controller. You can virtually plug virtual USB devices or real host USB devices (experimental, works only on Linux hosts). QEMU will automatically create and connect virtual USB hubs as necessary to connect multiple USB devices.
Connecting USB devices¶
USB devices can be connected with the -usbdevice commandline option
usb_add monitor command. Available devices are:
- Virtual Mouse. This will override the PS/2 mouse emulation when activated.
- Pointer device that uses absolute coordinates (like a touchscreen). This means QEMU is able to report the mouse position without having to grab the mouse. Also overrides the PS/2 mouse emulation when activated.
- Mass storage device based on file (see disk_images)
- Pass through the host device identified by bus.addr (Linux only)
- Pass through the host device identified by vendor_id:product_id (Linux only)
- Virtual Wacom PenPartner tablet. This device is similar to the
tabletabove but it can be used with the tslib library because in addition to touch coordinates it reports touch pressure.
- Standard USB keyboard. Will override the PS/2 keyboard (if present).
Serial converter. This emulates an FTDI FT232BM chip connected to host character device dev. The available character devices are the same as for the
productidoptions can be used to override the default 0403:6001. For instance,
will connect to tcp port 4444 of ip 192.168.0.2, and plug that to the virtual serial converter, faking a Matrix Orbital LCD Display (USB ID 0403:FA00).
- Braille device. This will use BrlAPI to display the braille output on a real or fake device.
Network adapter that supports CDC ethernet and RNDIS protocols. options specifies NIC options as with
-net nic,options (see description). For instance, user-mode networking can be used with
qemu-system-i386 [...OPTIONS...] -net user,vlan=0 -usbdevice net:vlan=0
Currently this cannot be used in machines that support PCI NICs.
Bluetooth dongle whose type is specified in the same format as with the -bt hci option, see allowed HCI types. If no type is given, the HCI logic corresponds to
-bt hci,vlan=0. This USB device implements the USB Transport Layer of HCI. Example usage:
qemu-system-i386 [...OPTIONS...] -usbdevice bt:hci,vlan=3 -bt device:keyboard,vlan=3
Using host USB devices on a Linux host¶
WARNING: this is an experimental feature. QEMU will slow down when using it. USB devices requiring real time streaming (i.e. USB Video Cameras) are not supported yet.
If you use an early Linux 2.4 kernel, verify that no Linux driver is actually using the USB device. A simple way to do that is simply to disable the corresponding kernel module by renaming it from mydriver.o to mydriver.o.disabled.
Verify that /proc/bus/usb is working (most Linux distributions should enable it by default). You should see something like that:
ls /proc/bus/usb 001 devices drivers
Since only root can access to the USB devices directly, you can either launch QEMU as root or change the permissions of the USB devices you want to use. For testing, the following suffices:
chown -R myuid /proc/bus/usb
Launch QEMU and do in the monitor:
info usbhost Device 1.2, speed 480 Mb/s Class 00: USB device 1234:5678, USB DISK
You should see the list of the devices you can use (Never try to use hubs, it won’t work).
Add the device in QEMU by using:
Normally the guest OS should report that a new USB device is plugged. You can use the option -usbdevice to do the same.
Now you can try to use the host USB device in QEMU.
When relaunching QEMU, you may have to unplug and plug again the USB device to make it work again (this is a bug).