1 2USB Quick Start 3=============== 4 5XHCI controller support 6----------------------- 7 8QEMU has XHCI host adapter support. The XHCI hardware design is much 9more virtualization-friendly when compared to EHCI and UHCI, thus XHCI 10emulation uses less resources (especially cpu). So if your guest 11supports XHCI (which should be the case for any operating system 12released around 2010 or later) we recommend using it: 13 14 qemu -device qemu-xhci 15 16XHCI supports USB 1.1, USB 2.0 and USB 3.0 devices, so this is the 17only controller you need. With only a single USB controller (and 18therefore only a single USB bus) present in the system there is no 19need to use the bus= parameter when adding USB devices. 20 21 22EHCI controller support 23----------------------- 24 25The QEMU EHCI Adapter supports USB 2.0 devices. It can be used either 26standalone or with companion controllers (UHCI, OHCI) for USB 1.1 27devices. The companion controller setup is more convenient to use 28because it provides a single USB bus supporting both USB 2.0 and USB 291.1 devices. See next section for details. 30 31When running EHCI in standalone mode you can add UHCI or OHCI 32controllers for USB 1.1 devices too. Each controller creates its own 33bus though, so there are two completely separate USB buses: One USB 341.1 bus driven by the UHCI controller and one USB 2.0 bus driven by 35the EHCI controller. Devices must be attached to the correct 36controller manually. 37 38The easiest way to add a UHCI controller to a 'pc' machine is the 39'-usb' switch. QEMU will create the UHCI controller as function of 40the PIIX3 chipset. The USB 1.1 bus will carry the name "usb-bus.0". 41 42You can use the standard -device switch to add a EHCI controller to 43your virtual machine. It is strongly recommended to specify an ID for 44the controller so the USB 2.0 bus gets an individual name, for example 45'-device usb-ehci,id=ehci". This will give you a USB 2.0 bus named 46"ehci.0". 47 48When adding USB devices using the -device switch you can specify the 49bus they should be attached to. Here is a complete example: 50 51 qemu -M pc ${otheroptions} \ 52 -drive if=none,id=usbstick,file=/path/to/image \ 53 -usb \ 54 -device usb-ehci,id=ehci \ 55 -device usb-tablet,bus=usb-bus.0 \ 56 -device usb-storage,bus=ehci.0,drive=usbstick 57 58This attaches a USB tablet to the UHCI adapter and a USB mass storage 59device to the EHCI adapter. 60 61 62Companion controller support 63---------------------------- 64 65The UHCI and OHCI controllers can attach to a USB bus created by EHCI 66as companion controllers. This is done by specifying the masterbus 67and firstport properties. masterbus specifies the bus name the 68controller should attach to. firstport specifies the first port the 69controller should attach to, which is needed as usually one EHCI 70controller with six ports has three UHCI companion controllers with 71two ports each. 72 73There is a config file in docs which will do all this for 74you, just try ... 75 76 qemu -readconfig docs/config/ich9-ehci-uhci.cfg 77 78... then use "bus=ehci.0" to assign your USB devices to that bus. 79 80Using the '-usb' switch for 'q35' machines will create a similar 81USB controller configuration. 82 83 84More USB tips & tricks 85====================== 86 87Recently the USB pass through driver (also known as usb-host) and the 88QEMU USB subsystem gained a few capabilities which are available only 89via qdev properties, i,e. when using '-device'. 90 91 92physical port addressing 93------------------------ 94 95First you can (for all USB devices) specify the physical port where 96the device will show up in the guest. This can be done using the 97"port" property. UHCI has two root ports (1,2). EHCI has six root 98ports (1-6), the emulated (1.1) USB hub has eight ports. 99 100Plugging a tablet into UHCI port 1 works like this: 101 102 -device usb-tablet,bus=usb-bus.0,port=1 103 104Plugging a hub into UHCI port 2 works like this: 105 106 -device usb-hub,bus=usb-bus.0,port=2 107 108Plugging a virtual USB stick into port 4 of the hub just plugged works 109this way: 110 111 -device usb-storage,bus=usb-bus.0,port=2.4,drive=... 112 113You can do basically the same in the monitor using the device_add 114command. If you want to unplug devices too you should specify some 115unique id which you can use to refer to the device ... 116 117 (qemu) device_add usb-tablet,bus=usb-bus.0,port=1,id=my-tablet 118 (qemu) device_del my-tablet 119 120... when unplugging it with device_del. 121 122 123USB pass through hints 124---------------------- 125 126The usb-host driver has a bunch of properties to specify the device 127which should be passed to the guest: 128 129 hostbus=<nr> -- Specifies the bus number the device must be attached 130 to. 131 132 hostaddr=<nr> -- Specifies the device address the device got 133 assigned by the guest os. 134 135 hostport=<str> -- Specifies the physical port the device is attached 136 to. 137 138 vendorid=<hexnr> -- Specifies the vendor ID of the device. 139 productid=<hexnr> -- Specifies the product ID of the device. 140 141In theory you can combine all these properties as you like. In 142practice only a few combinations are useful: 143 144 (1) vendorid+productid -- match for a specific device, pass it to 145 the guest when it shows up somewhere in the host. 146 147 (2) hostbus+hostport -- match for a specific physical port in the 148 host, any device which is plugged in there gets passed to the 149 guest. 150 151 (3) hostbus+hostaddr -- most useful for ad-hoc pass through as the 152 hostaddr isn't stable, the next time you plug in the device it 153 gets a new one ... 154 155Note that USB 1.1 devices are handled by UHCI/OHCI and USB 2.0 by 156EHCI. That means a device plugged into the very same physical port 157may show up on different buses depending on the speed. The port I'm 158using for testing is bus 1 + port 1 for 2.0 devices and bus 3 + port 1 159for 1.1 devices. Passing through any device plugged into that port 160and also assign them to the correct bus can be done this way: 161 162 qemu -M pc ${otheroptions} \ 163 -usb \ 164 -device usb-ehci,id=ehci \ 165 -device usb-host,bus=usb-bus.0,hostbus=3,hostport=1 \ 166 -device usb-host,bus=ehci.0,hostbus=1,hostport=1 167 168enjoy, 169 Gerd 170 171-- 172Gerd Hoffmann <kraxel@redhat.com> 173