I use qemu-2.5.0. This is a part of my xml: ......
<vcpu placement='static' current="1">64</vcpu> <cpu> <topology sockets='4' cores='8' threads='2'/> <numa> <cell cpus='0-3' memory='524288'/> <cell cpus='4-7' memory='524288'/> </numa> </cpu> ..... <hostdev mode='subsystem' type='usb' managed='yes'> <source missing='yes'> <address bus='1' device='5'/> </source> <address type='usb' bus='0' port='4'/> </hostdev> .... and this xml will failed to install win2008 with usb, and qemu reports in its log: cpage out of range(EHCI) 。 but if the part of xml above: <vcpu placement='static' current="1">64</vcpu> changes to <vcpu placement='static' cpuset='0-1' current="1">64</vcpu> , and other part of xml stay the same. Then it works, I can install win2008 with usb successfully. I change my qemu to 2.8.0, and the first xml can work too, but I don't know the reason, and which part of qemu code fix this bug. Ask for help