Red Hat Bugzilla – Bug 1271408
RFE: qemu: support configuring # of ports for qemu usb3 controller
Last modified: 2016-05-04 05:46:52 EDT
According to Gerd here:
qemu's xhci controller has a configurable number of ports. libvirt should support that, since the default is only 4.
Gerd, is this all that's required to give the xhci controller ex. 8 ports?
Also, any opinions on if we should expose p2 vs p3 or just a single 'ports' knob? I don't know what the usecase for configuring only one or the other is...
p2 is the number of usb2 ports, p3 is the number of usb4 ports. Ports do overlap. So for example p2=8,p2=4 gives you a xhci controller where ports 1-4 can do both usb2 and usb3, whereas ports 5-8 are usb2 only.
That is mostly useful for debugging/testing purposes, for example forcing devices into usb2 mode on xhci to see whenever this works correctly.
I'd suggest to expose this as a single ports= property in libvirt.
Patches posted upstream: http://www.redhat.com/archives/libvir-list/2016-April/msg01829.html
Author: Cole Robinson <email@example.com>
Date: Sat Apr 23 19:52:56 2016 -0400
qemu: support configuring usb3 controller port count
This adds a ports= attribute to usb controller XML, like
<controller type='usb' model='nec-xhci' ports='8'/>
This maps to:
qemu -device nec-usb-xhci,p2=8,p3=8
Meaning, 8 ports that support both usb2 and usb3 devices. Gerd
suggested to just expose them as one knob.