[virt-tools-list] Problem accessing USB devices under a VM running Windows 10

Christophe Fergeau cfergeau at redhat.com
Tue Feb 7 15:54:34 UTC 2017


On Mon, Feb 06, 2017 at 11:19:08AM -0800, Jeffery Small wrote:
> 
> I'm on an Xubuntu 16.10 system running the latest version of QEMU-KVM
> (1.2.6.1).  I have a VM running Windows 10, which is launched from
> virt-manager.
> 
> Question #1:
> 
> With the OS not running, from the Hardware Details page I have used "Add
> Hardware" to attach a USB flash drive.  In the hardware list it shows
> up as "USB 058f:6387" and the details show "Device: 002:003 Alcor Micro
> Corp. Flash Drive".
> 
> Nevertheless, when I launch the Windows 10 OS, File Explorer does not see
> this device.  I've also looked in Device Manager and can see no reference
> to the flash drive.
> 
> Any clue as to the nature of the problem and what must be done to make this
> visible to the Windows OS?  I am doing this with a flash drive as a test in
> order to get device attachment working.  Ultimately, I will be attaching a
> usb dongle key to the port which must be seen by a program running in this
> environment.

And this device has a partition table, and a file system Windows knows
about ? Last time I used Windows, I could find a place showing the
various partitions on the device, did you check there?

> 
> 
> Question #2:
> 
> There was no problem adding the Alcor flash drive and it is the only device
> I have added manually, but when I attempt to add another flash drive or my
> attached phone, virt-manager reports:
> 
>   "Error adding device: internal error: No free USB ports"
> 
> Error details:
> 
>   Traceback (most recent call last):
>   File "/usr/share/virt-manager/virtManager/addhardware.py", line 1343, in _add_device
>   self.vm.add_device(self._dev)
>   File "/usr/share/virt-manager/virtManager/domain.py", line 568, in add_device
>   self._redefine_xmlobj(xmlobj)
>   File "/usr/share/virt-manager/virtManager/libvirtobject.py", line 389, in _redefine_xmlobj
>   self._define(newxml)
>   File "/usr/share/virt-manager/virtManager/domain.py", line 1094, in _define
>   self.conn.define_domain(newxml)
>   File "/usr/share/virt-manager/virtManager/connection.py", line 677, in define_domain
>   return self._backend.defineXML(xml)
>   File "/usr/lib/python2.7/dist-packages/libvirt.py", line 3800, in defineXML
>   if ret is None:raise libvirtError('virDomainDefineXML() failed', conn=self)
>   libvirtError: internal error: No free USB ports
> 
> Having support for only one external USB port is surprising.  Can you
> point me to any documentation that indicates how to address this problem
> and add additional ports?

You need one "USB Redirector" device in virt-manager per USB device you want to redirect
simultaneously.

Christophe
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