Bug 1271408

Summary:	RFE: qemu: support configuring # of ports for qemu usb3 controller
Product:	[Community] Virtualization Tools	Reporter:	Cole Robinson <crobinso>
Component:	libvirt	Assignee:	Libvirt Maintainers <libvirt-maint>
Status:	CLOSED UPSTREAM	QA Contact:
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	unspecified	CC:	dyuan, kraxel, pzhang, rbalakri
Target Milestone:	---
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2016-05-03 13:03:51 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Cole Robinson 2015-10-13 22:15:46 UTC

According to Gerd here:

https://bugzilla.redhat.com/show_bug.cgi?id=1135488#c10

qemu's xhci controller has a configurable number of ports. libvirt should support that, since the default is only 4.

Comment 1 Cole Robinson 2015-10-13 22:23:54 UTC

Gerd, is this all that's required to give the xhci controller ex. 8 ports?

  -device nec-usb-xhci,p2=8,p3=8

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...

Comment 2 Gerd Hoffmann 2015-10-14 05:48:22 UTC

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.

Comment 3 Cole Robinson 2016-04-27 18:30:38 UTC

Patches posted upstream: http://www.redhat.com/archives/libvir-list/2016-April/msg01829.html

Comment 4 Cole Robinson 2016-05-03 13:03:51 UTC

Upstream now:

commit 600977e293ee97fc53a7ef17fb89cb310560e7ab
Author: Cole Robinson <crobinso>
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.