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Re: IMPORTANT - : Need help on USB port virtualization with Xen hypervisor



On 16.03.24 00:32, Stefano Stabellini wrote:
Hi Dominique,

You posted this configuration:

device_model_args = [ "
                       "-device","nec-usb-xhci,id=xhci",
                       "-device","usb-host,bus=xhci.0,hostbus=1,hostport=13",
                       "-device","usb-host,bus=xhci.0,hostbus=1,hostport=10",
                       "-device","usb-host,bus=xhci.0,hostbus=1,hostport=2",
                       "-device","usb-host,bus=xhci.0,hostbus=2,hostport=2",
                       "-device","usb-host,bus=xhci.0,hostbus=2,hostport=1",
                       "-device","usb-host,bus=xhci.0,hostbus=1,hostport=1"]

It looks like you are using QEMU-based USB passthrough. Basically QEMU
(independently from Xen) is accessing the USB device in Dom0 and
exposing a corresponding device to the guest. I am not sure if there is
anything that can be done in QEMU to support USB 3.0 with high speed,
people in CC might know.

There two other alternatives to this approach. You can use PV USB
Passthrough instead. Juergen (CCed) is the original author. I am not
sure if that supports USB 3.0 either.

PV USB doesn't support USB 3.0.

Instead of using device_model_args= in the guest configuration I'd rather
use the usbctrl= and usbdev= items (see the related xl.cfg(5) man page).
I'm not sure this will really make a performance difference, though.


Juergen




 


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