-USB 2.0 Quick Start
-===================
+USB Quick Start
+===============
-The QEMU EHCI Adapter can be used with and without companion
-controllers. See below for the companion controller mode.
+XHCI controller support
+-----------------------
+
+QEMU has XHCI host adapter support. The XHCI hardware design is much
+more virtualization-friendly when compared to EHCI and UHCI, thus XHCI
+emulation uses less resources (especially cpu). So if your guest
+supports XHCI (which should be the case for any operating system
+released around 2010 or later) we recommend using it:
+
+ qemu -device qemu-xhci
-When not running in companion controller mode there are two completely
-separate USB busses: One USB 1.1 bus driven by the UHCI controller and
-one USB 2.0 bus driven by the EHCI controller. Devices must be
-attached to the correct controller manually.
+XHCI supports USB 1.1, USB 2.0 and USB 3.0 devices, so this is the
+only controller you need. With only a single USB controller (and
+therefore only a single USB bus) present in the system there is no
+need to use the bus= parameter when adding USB devices.
+
+
+EHCI controller support
+-----------------------
-The '-usb' switch will make qemu create the UHCI controller as part of
+The QEMU EHCI Adapter supports USB 2.0 devices. It can be used either
+standalone or with companion controllers (UHCI, OHCI) for USB 1.1
+devices. The companion controller setup is more convenient to use
+because it provides a single USB bus supporting both USB 2.0 and USB
+1.1 devices. See next section for details.
+
+When running EHCI in standalone mode you can add UHCI or OHCI
+controllers for USB 1.1 devices too. Each controller creates its own
+bus though, so there are two completely separate USB buses: One USB
+1.1 bus driven by the UHCI controller and one USB 2.0 bus driven by
+the EHCI controller. Devices must be attached to the correct
+controller manually.
+
+The easiest way to add a UHCI controller to a 'pc' machine is the
+'-usb' switch. QEMU will create the UHCI controller as function of
the PIIX3 chipset. The USB 1.1 bus will carry the name "usb-bus.0".
You can use the standard -device switch to add a EHCI controller to
your virtual machine. It is strongly recommended to specify an ID for
-the controller so the USB 2.0 bus gets a individual name, for example
+the controller so the USB 2.0 bus gets an individual name, for example
'-device usb-ehci,id=ehci". This will give you a USB 2.0 bus named
"ehci.0".
-I strongly recommend to also use -device to attach usb devices because
-you can specify the bus they should be attached to this way. Here is
-a complete example:
+When adding USB devices using the -device switch you can specify the
+bus they should be attached to. Here is a complete example:
qemu -M pc ${otheroptions} \
-drive if=none,id=usbstick,file=/path/to/image \
-device usb-tablet,bus=usb-bus.0 \
-device usb-storage,bus=ehci.0,drive=usbstick
-This attaches a usb tablet to the UHCI adapter and a usb mass storage
+This attaches a USB tablet to the UHCI adapter and a USB mass storage
device to the EHCI adapter.
Companion controller support
----------------------------
-Companion controller support has been added recently. The operational
-model described above with two completely separate busses still works
-fine. Additionally the UHCI and OHCI controllers got the ability to
-attach to a usb bus created by EHCI as companion controllers. This is
-done by specifying the masterbus and firstport properties. masterbus
-specifies the bus name the controller should attach to. firstport
-specifies the first port the controller should attach to, which is
-needed as usually one ehci controller with six ports has three uhci
-companion controllers with two ports each.
+The UHCI and OHCI controllers can attach to a USB bus created by EHCI
+as companion controllers. This is done by specifying the masterbus
+and firstport properties. masterbus specifies the bus name the
+controller should attach to. firstport specifies the first port the
+controller should attach to, which is needed as usually one EHCI
+controller with six ports has three UHCI companion controllers with
+two ports each.
-There is a config file in docs which will do all this for you, just
-try ...
-
- qemu -readconfig docs/ich9-ehci-uhci.cfg
-
-... then use "bus=ehci.0" to assign your usb devices to that bus.
-
-
-xhci controller support
------------------------
+There is a config file in docs which will do all this for
+you, just try ...
-There is also xhci host controller support available. It got a lot
-less testing than ehci and there are a bunch of known limitations, so
-ehci may work better for you. On the other hand the xhci hardware
-design is much more virtualization-friendly, thus xhci emulation uses
-less resources (especially cpu). If you want to give xhci a try
-use this to add the host controller ...
+ qemu -readconfig docs/config/ich9-ehci-uhci.cfg
- qemu -device nec-usb-xhci,id=xhci
+... then use "bus=ehci.0" to assign your USB devices to that bus.
-... then use "bus=xhci.0" when assigning usb devices.
+Using the '-usb' switch for 'q35' machines will create a similar
+USB controller configuration.
More USB tips & tricks
======================
-Recently the usb pass through driver (also known as usb-host) and the
-qemu usb subsystem gained a few capabilities which are available only
+Recently the USB pass through driver (also known as usb-host) and the
+QEMU USB subsystem gained a few capabilities which are available only
via qdev properties, i,e. when using '-device'.
physical port addressing
------------------------
-First you can (for all usb devices) specify the physical port where
+First you can (for all USB devices) specify the physical port where
the device will show up in the guest. This can be done using the
-"port" property. UHCI has two root ports (1,2). EHCI has four root
-ports (1-4), the emulated (1.1) USB hub has eight ports.
+"port" property. UHCI has two root ports (1,2). EHCI has six root
+ports (1-6), the emulated (1.1) USB hub has eight ports.
Plugging a tablet into UHCI port 1 works like this:
-device usb-hub,bus=usb-bus.0,port=2
-Plugging a virtual usb stick into port 4 of the hub just plugged works
+Plugging a virtual USB stick into port 4 of the hub just plugged works
this way:
-device usb-storage,bus=usb-bus.0,port=2.4,drive=...
Note that USB 1.1 devices are handled by UHCI/OHCI and USB 2.0 by
EHCI. That means a device plugged into the very same physical port
-may show up on different busses depending on the speed. The port I'm
+may show up on different buses depending on the speed. The port I'm
using for testing is bus 1 + port 1 for 2.0 devices and bus 3 + port 1
for 1.1 devices. Passing through any device plugged into that port
and also assign them to the correct bus can be done this way:
projects / qemu.git / blobdiff