xref: /qemu/docs/system/devices/usb.rst (revision 118d4ed0453c325828e3678608cf32fd9c4a8c49)
1 .. _pcsys_005fusb:
2 
3 USB emulation
4 -------------
5 
6 QEMU can emulate a PCI UHCI, OHCI, EHCI or XHCI USB controller. You can
7 plug virtual USB devices or real host USB devices (only works with
8 certain host operating systems). QEMU will automatically create and
9 connect virtual USB hubs as necessary to connect multiple USB devices.
10 
11 USB controllers
12 ~~~~~~~~~~~~~~~
13 
14 XHCI controller support
15 ^^^^^^^^^^^^^^^^^^^^^^^
16 
17 QEMU has XHCI host adapter support.  The XHCI hardware design is much
18 more virtualization-friendly when compared to EHCI and UHCI, thus XHCI
19 emulation uses less resources (especially CPU).  So if your guest
20 supports XHCI (which should be the case for any operating system
21 released around 2010 or later) we recommend using it:
22 
23     qemu -device qemu-xhci
24 
25 XHCI supports USB 1.1, USB 2.0 and USB 3.0 devices, so this is the
26 only controller you need.  With only a single USB controller (and
27 therefore only a single USB bus) present in the system there is no
28 need to use the bus= parameter when adding USB devices.
29 
30 
31 EHCI controller support
32 ^^^^^^^^^^^^^^^^^^^^^^^
33 
34 The QEMU EHCI Adapter supports USB 2.0 devices.  It can be used either
35 standalone or with companion controllers (UHCI, OHCI) for USB 1.1
36 devices.  The companion controller setup is more convenient to use
37 because it provides a single USB bus supporting both USB 2.0 and USB
38 1.1 devices.  See next section for details.
39 
40 When running EHCI in standalone mode you can add UHCI or OHCI
41 controllers for USB 1.1 devices too.  Each controller creates its own
42 bus though, so there are two completely separate USB buses: One USB
43 1.1 bus driven by the UHCI controller and one USB 2.0 bus driven by
44 the EHCI controller.  Devices must be attached to the correct
45 controller manually.
46 
47 The easiest way to add a UHCI controller to a ``pc`` machine is the
48 ``-usb`` switch.  QEMU will create the UHCI controller as function of
49 the PIIX3 chipset.  The USB 1.1 bus will carry the name ``usb-bus.0``.
50 
51 You can use the standard ``-device`` switch to add a EHCI controller to
52 your virtual machine.  It is strongly recommended to specify an ID for
53 the controller so the USB 2.0 bus gets an individual name, for example
54 ``-device usb-ehci,id=ehci``.  This will give you a USB 2.0 bus named
55 ``ehci.0``.
56 
57 When adding USB devices using the ``-device`` switch you can specify the
58 bus they should be attached to.  Here is a complete example:
59 
60 .. parsed-literal::
61 
62     |qemu_system| -M pc ${otheroptions}                        \\
63         -drive if=none,id=usbstick,format=raw,file=/path/to/image   \\
64         -usb                                                        \\
65         -device usb-ehci,id=ehci                                    \\
66         -device usb-tablet,bus=usb-bus.0                            \\
67         -device usb-storage,bus=ehci.0,drive=usbstick
68 
69 This attaches a USB tablet to the UHCI adapter and a USB mass storage
70 device to the EHCI adapter.
71 
72 
73 Companion controller support
74 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
75 
76 The UHCI and OHCI controllers can attach to a USB bus created by EHCI
77 as companion controllers.  This is done by specifying the ``masterbus``
78 and ``firstport`` properties.  ``masterbus`` specifies the bus name the
79 controller should attach to.  ``firstport`` specifies the first port the
80 controller should attach to, which is needed as usually one EHCI
81 controller with six ports has three UHCI companion controllers with
82 two ports each.
83 
84 There is a config file in docs which will do all this for
85 you, which you can use like this:
86 
87 .. parsed-literal::
88 
89    |qemu_system| -readconfig docs/config/ich9-ehci-uhci.cfg
90 
91 Then use ``bus=ehci.0`` to assign your USB devices to that bus.
92 
93 Using the ``-usb`` switch for ``q35`` machines will create a similar
94 USB controller configuration.
95 
96 
97 .. _Connecting USB devices:
98 
99 Connecting USB devices
100 ~~~~~~~~~~~~~~~~~~~~~~
101 
102 USB devices can be connected with the ``-device usb-...`` command line
103 option or the ``device_add`` monitor command. Available devices are:
104 
105 ``usb-mouse``
106    Virtual Mouse. This will override the PS/2 mouse emulation when
107    activated.
108 
109 ``usb-tablet``
110    Pointer device that uses absolute coordinates (like a touchscreen).
111    This means QEMU is able to report the mouse position without having
112    to grab the mouse. Also overrides the PS/2 mouse emulation when
113    activated.
114 
115 ``usb-storage,drive=drive_id``
116    Mass storage device backed by drive_id (see the :ref:`disk images`
117    chapter in the System Emulation Users Guide). This is the classic
118    bulk-only transport protocol used by 99% of USB sticks. This
119    example shows it connected to an XHCI USB controller and with
120    a drive backed by a raw format disk image:
121 
122    .. parsed-literal::
123 
124        |qemu_system| [...]                                   \\
125         -drive if=none,id=stick,format=raw,file=/path/to/file.img \\
126         -device nec-usb-xhci,id=xhci                              \\
127         -device usb-storage,bus=xhci.0,drive=stick
128 
129 ``usb-uas``
130    USB attached SCSI device. This does not create a SCSI disk, so
131    you need to explicitly create a ``scsi-hd`` or ``scsi-cd`` device
132    on the command line, as well as using the ``-drive`` option to
133    specify what those disks are backed by. One ``usb-uas`` device can
134    handle multiple logical units (disks). This example creates three
135    logical units: two disks and one cdrom drive:
136 
137    .. parsed-literal::
138 
139       |qemu_system| [...]                                         \\
140        -drive if=none,id=uas-disk1,format=raw,file=/path/to/file1.img  \\
141        -drive if=none,id=uas-disk2,format=raw,file=/path/to/file2.img  \\
142        -drive if=none,id=uas-cdrom,media=cdrom,format=raw,file=/path/to/image.iso \\
143        -device nec-usb-xhci,id=xhci                                    \\
144        -device usb-uas,id=uas,bus=xhci.0                               \\
145        -device scsi-hd,bus=uas.0,scsi-id=0,lun=0,drive=uas-disk1       \\
146        -device scsi-hd,bus=uas.0,scsi-id=0,lun=1,drive=uas-disk2       \\
147        -device scsi-cd,bus=uas.0,scsi-id=0,lun=5,drive=uas-cdrom
148 
149 ``usb-bot``
150    Bulk-only transport storage device. This presents the guest with the
151    same USB bulk-only transport protocol interface as ``usb-storage``, but
152    the QEMU command line option works like ``usb-uas`` and does not
153    automatically create SCSI disks for you. ``usb-bot`` supports up to
154    16 LUNs. Unlike ``usb-uas``, the LUN numbers must be continuous,
155    i.e. for three devices you must use 0+1+2. The 0+1+5 numbering from the
156    ``usb-uas`` example above won't work with ``usb-bot``.
157 
158 ``usb-mtp,rootdir=dir``
159    Media transfer protocol device, using dir as root of the file tree
160    that is presented to the guest.
161 
162 ``usb-host,hostbus=bus,hostaddr=addr``
163    Pass through the host device identified by bus and addr
164 
165 ``usb-host,vendorid=vendor,productid=product``
166    Pass through the host device identified by vendor and product ID
167 
168 ``usb-wacom-tablet``
169    Virtual Wacom PenPartner tablet. This device is similar to the
170    ``tablet`` above but it can be used with the tslib library because in
171    addition to touch coordinates it reports touch pressure.
172 
173 ``usb-kbd``
174    Standard USB keyboard. Will override the PS/2 keyboard (if present).
175 
176 ``usb-serial,chardev=id``
177    Serial converter. This emulates an FTDI FT232BM chip connected to
178    host character device id.
179 
180 ``usb-braille,chardev=id``
181    Braille device. This will use BrlAPI to display the braille output on
182    a real or fake device referenced by id.
183 
184 ``usb-net[,netdev=id]``
185    Network adapter that supports CDC ethernet and RNDIS protocols. id
186    specifies a netdev defined with ``-netdev …,id=id``. For instance,
187    user-mode networking can be used with
188 
189    .. parsed-literal::
190 
191       |qemu_system| [...] -netdev user,id=net0 -device usb-net,netdev=net0
192 
193 ``usb-ccid``
194    Smartcard reader device
195 
196 ``usb-audio``
197    USB audio device
198 
199 ``u2f-{emulated,passthru}``
200    Universal Second Factor device
201 
202 ``canokey``
203    An Open-source Secure Key implementing FIDO2, OpenPGP, PIV and more.
204    For more information, see :ref:`canokey`.
205 
206 Physical port addressing
207 ^^^^^^^^^^^^^^^^^^^^^^^^
208 
209 For all the above USB devices, by default QEMU will plug the device
210 into the next available port on the specified USB bus, or onto
211 some available USB bus if you didn't specify one explicitly.
212 If you need to, you can also specify the physical port where
213 the device will show up in the guest.  This can be done using the
214 ``port`` property.  UHCI has two root ports (1,2).  EHCI has six root
215 ports (1-6), and the emulated (1.1) USB hub has eight ports.
216 
217 Plugging a tablet into UHCI port 1 works like this::
218 
219         -device usb-tablet,bus=usb-bus.0,port=1
220 
221 Plugging a hub into UHCI port 2 works like this::
222 
223         -device usb-hub,bus=usb-bus.0,port=2
224 
225 Plugging a virtual USB stick into port 4 of the hub just plugged works
226 this way::
227 
228         -device usb-storage,bus=usb-bus.0,port=2.4,drive=...
229 
230 In the monitor, the ``device_add` command also accepts a ``port``
231 property specification. If you want to unplug devices too you should
232 specify some unique id which you can use to refer to the device.
233 You can then use ``device_del`` to unplug the device later.
234 For example::
235 
236         (qemu) device_add usb-tablet,bus=usb-bus.0,port=1,id=my-tablet
237         (qemu) device_del my-tablet
238 
239 Hotplugging USB storage
240 ~~~~~~~~~~~~~~~~~~~~~~~
241 
242 The ``usb-bot`` and ``usb-uas`` devices can be hotplugged.  In the hotplug
243 case they are added with ``attached = false`` so the guest will not see
244 the device until the ``attached`` property is explicitly set to true.
245 That allows you to attach one or more scsi devices before making the
246 device visible to the guest. The workflow looks like this:
247 
248 #. ``device-add usb-bot,id=foo``
249 #. ``device-add scsi-{hd,cd},bus=foo.0,lun=0``
250 #. optionally add more devices (luns 1 ... 15)
251 #. ``scripts/qmp/qom-set foo.attached = true``
252 
253 .. _host_005fusb_005fdevices:
254 
255 Using host USB devices on a Linux host
256 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
257 
258 WARNING: this is an experimental feature. QEMU will slow down when using
259 it. USB devices requiring real time streaming (i.e. USB Video Cameras)
260 are not supported yet.
261 
262 1. If you use an early Linux 2.4 kernel, verify that no Linux driver is
263    actually using the USB device. A simple way to do that is simply to
264    disable the corresponding kernel module by renaming it from
265    ``mydriver.o`` to ``mydriver.o.disabled``.
266 
267 2. Verify that ``/proc/bus/usb`` is working (most Linux distributions
268    should enable it by default). You should see something like that:
269 
270    ::
271 
272       ls /proc/bus/usb
273       001  devices  drivers
274 
275 3. Since only root can access to the USB devices directly, you can
276    either launch QEMU as root or change the permissions of the USB
277    devices you want to use. For testing, the following suffices:
278 
279    ::
280 
281       chown -R myuid /proc/bus/usb
282 
283 4. Launch QEMU and do in the monitor:
284 
285    ::
286 
287       info usbhost
288         Device 1.2, speed 480 Mb/s
289           Class 00: USB device 1234:5678, USB DISK
290 
291    You should see the list of the devices you can use (Never try to use
292    hubs, it won't work).
293 
294 5. Add the device in QEMU by using:
295 
296    ::
297 
298       device_add usb-host,vendorid=0x1234,productid=0x5678
299 
300    Normally the guest OS should report that a new USB device is plugged.
301    You can use the option ``-device usb-host,...`` to do the same.
302 
303 6. Now you can try to use the host USB device in QEMU.
304 
305 When relaunching QEMU, you may have to unplug and plug again the USB
306 device to make it work again (this is a bug).
307 
308 ``usb-host`` properties for specifying the host device
309 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
310 
311 The example above uses the ``vendorid`` and ``productid`` to
312 specify which host device to pass through, but this is not
313 the only way to specify the host device. ``usb-host`` supports
314 the following properties:
315 
316 ``hostbus=<nr>``
317   Specifies the bus number the device must be attached to
318 ``hostaddr=<nr>``
319   Specifies the device address the device got assigned by the guest os
320 ``hostport=<str>``
321   Specifies the physical port the device is attached to
322 ``vendorid=<hexnr>``
323   Specifies the vendor ID of the device
324 ``productid=<hexnr>``
325   Specifies the product ID of the device.
326 
327 In theory you can combine all these properties as you like.  In
328 practice only a few combinations are useful:
329 
330 - ``vendorid`` and ``productid`` -- match for a specific device, pass it to
331   the guest when it shows up somewhere in the host.
332 
333 - ``hostbus`` and ``hostport`` -- match for a specific physical port in the
334   host, any device which is plugged in there gets passed to the
335   guest.
336 
337 - ``hostbus`` and ``hostaddr`` -- most useful for ad-hoc pass through as the
338   hostaddr isn't stable. The next time you plug the device into the host it
339   will get a new hostaddr.
340 
341 Note that on the host USB 1.1 devices are handled by UHCI/OHCI and USB
342 2.0 by EHCI.  That means different USB devices plugged into the very
343 same physical port on the host may show up on different host buses
344 depending on the speed. Supposing that devices plugged into a given
345 physical port appear as bus 1 + port 1 for 2.0 devices and bus 3 + port 1
346 for 1.1 devices, you can pass through any device plugged into that port
347 and also assign it to the correct USB bus in QEMU like this:
348 
349 .. parsed-literal::
350 
351    |qemu_system| -M pc [...]                            \\
352         -usb                                                 \\
353         -device usb-ehci,id=ehci                             \\
354         -device usb-host,bus=usb-bus.0,hostbus=3,hostport=1  \\
355         -device usb-host,bus=ehci.0,hostbus=1,hostport=1
356