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

[GOURLOT Francois <francois.gourlot@xxxxxxxxxxxxxxx>]

Dear Rob and Julien,

 

Thank you for your messages.

 

Dominique and the Thales crew will give you more information quickly.

 

Best regards

 

Responsable Programme

Département RAFALE F4

Thales SIX GTS France

T: +33(0) 1 41 30 26 67

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4 Avenue des Louvresses

92622 Gennevilliers

France

 

 

De : Rob Townley <rob.townley@xxxxxxxxx> De
Envoyé : dimanche 25 février 2024 13:20
À : Julien Grall <julien@xxxxxxx>
Cc : Andrew Cooper <andrew.cooper3@xxxxxxxxxx>; GOURLOT Francois <francois.gourlot@xxxxxxxxxxxxxxx>; George Dunlap <george.dunlap@xxxxxxxxxx>; Jan Beulich <jbeulich@xxxxxxxx>; Juergen Gross <jgross@xxxxxxxx>; Kelly Choi <kelly.choi@xxxxxxxxx>; Roger Pau Monné <roger.pau@xxxxxxxxxx>; xen-devel@xxxxxxxxxxxxxxxxxxxx
Objet : Re: IMPORTANT - : Need help on USB port virtualization with Xen hypervisor

 

In short, purchase an addon PCIe USB card to isolate traffic.  USB is a shared medium and is rooted in the cheapest electronics.   It was never considered enterprise grade hardware for most all of history.    The letter B in  USB  stands for BUS which actually means a shared roadway that other USB devices can and do impede traffic.   We experienced interfering traffic on inexpensive laptops running  XEN based Qubes-OS.  Turned out the WiFi card was actually wired onto the USB bus.   Unplugging all external USB electronics reduced inexplicable WiFi disconnects and reliably improved throughput.    However, there was no way to remove the keyboard, touchpad, and touchscreen which all used the USB roadway.   

 

Those were cheap laptops, but even enterprise class hardware such as HPE  and Dell Servers running XCP-NG did not have great speeds.   But in this scenario, we could simplify the problem and  isolate the issue by purchasing a  new add-on PCIe card with USB ports and then assign the entire PCIe card to the VM.   The VM would then have entire control of the PCIe card and isolate traffic to devices plugged into that card.  

 

I did not know until later that Wireshark has plugins for sniffing USB traffic, but my name is  not Heisenberg and not sure if that traffic monitoring does not also slow down other devices.  

 

On Sat, Feb 24, 2024 at 8:39 AM Julien Grall <julien@xxxxxxx> wrote:

Hi Dominique and Francois,

Thank you for the report. I am CCing some person who I think could help.

I also have some questions (see below).

On 23/02/2024 16:00, GOURLOT Francois wrote:
> Dear All,
>
> We send you a message few days ago.
>
> We have major performance with XEN USB Drivers. We use your driver to
> load data in a device and we need USB3 High Speed USB protocole
>
> Do you have a new issue of the HCI and NEC USB Xen Driver ?
p
[...]

> *De :*LARRIEU Dominique <dominique.larrieu@xxxxxxxxxxxxxxx>
> *Envoyé :* jeudi 22 février 2024 13:58
> *À :* xen-devel@xxxxxxxxxxxxxxxxxxxx
> *Cc :* WILLEMS Louis <louis.willems@xxxxxxxxxxxxxxx>; GRUO Nicolas
> <nicolas-n.gruo@xxxxxxxxxxxxxxx>; GOURLOT Francois
> <francois.gourlot@xxxxxxxxxxxxxxx>; Kelly Choi <kelly.choi@xxxxxxxxx>
> *Objet :* Need help on USB port virtualization with Xen hypervisor
> *Critère de diffusion :* Confidentiel
>
>     Dear all,
>
>     We are detectingseveral issues with USB port virtualization with the
>     Xen hypervisor.

Just to clarify, you are assigning the PCI USB bus (rather than just the
USB device) to the guest. Is that correct?

If so...

 >
 > Do you have a new issue of the HCI and NEC USB Xen Driver ?

... I am not sure what Xen driver you are talking about. If the USB bus
is assigned to the guest, then I would expect no specific Xen driver are
required. Do you have any pointer to the existing one?

>     - We cannot do PCI passthrough of the PCI usb bus on a Windows 10
>     1607 64-bit virtual machine. The bad result is a Windows blue screen.
>
>     - When we use the passthrough functionality on a Windows 21H2
>     virtual machine, we notice thatthe speed of the USB port is not high
>     speed but full speed on a USB 3.0 port
>
>     - We notice instabilities when using the nec-usb-xhci driver,  USB
>     2.0 keys are not recognized by the Windows virtual machine
>     (incorrect descriptor)

Do you have any logs you could share from the guest OS? Also, would you
be able to share more details on how you configure the guest? (e.g. xl
configuration, libvirt...)?

>
>     We needyour helpto find a solution for these problems.
>
>     The Software used are :

Can you share some details of the HW you are using?

>
>     -Debian 11 version5.10.0-20
>
>     -Xen version4.14

Are minor version of Xen 4.14 are you using? Any patches on top?

Xen 4.14 has also been out of support for a few months now. If that's
possible, I would recommend to try a new Xen version (the last stable is
4.18) just in case your issue as been fixed in newer release.

>
>     -Windows 10 1607 and 21H2 for virtual machines. Virtual Machine HVM

Cheers,

--
Julien Grall