Re: [Qemu-devel] USB Passthrough not working for Windows 7 guest

[Jan Kiszka]

On 2013-11-05 17:01, Frederich, Jens wrote:
> Hi all,
> 
> we're currently evaluating different RTOS systems (Windows CE, Intime, RTX, 
> etc.).
> One system is Linux RT + KVM/QEMU with a Windows 7 guest. Up to now all
> works fine, Linux RT has good latency and KVM/Qemu setup was easy. But one 
> QEMU bug
> breaks my measurement setup and evaluation.
> 
> I've some usb devices for the Windows 7 guest. I configure them as USB 
> passthrough.
> The devices appears in the device manager of Windows 7, but with
> "Error code 10": device cannot start". The Windows driver fails on USB set 
> configuration.
> The driver creates a IRP and send it via IOCTRL to lower layer. The IOCTRL 
> fails with
> invalid parameter.
> 
> driver log:
> 00000009      0.65470564      vnCDrvUsbControlRequestSetConfiguration, 
> WdfUsbTargetDeviceSelectConfig single interface failed 0xc000000d      
> 00000010      0.65472370      vnCDrvUsbIFPrepareHardwareState, 
> vnCDrvUsbControlRequestSetConfiguration failed: 0xc000000d     
> 00000011      0.65473646      vnCDrvDevConPrepareHardware, 
> vnCDrvUsbIFPrepareHardwareState failed 0xc000000d  
> 00000012      0.65474838      vnCDrvEvtDevicePrepareHardware, 
> vnCDrvDevConPrepareHardware failed 0xc0000001   
> 00000013      0.6547
> 
> This bug breaks my latency measurement setup and Linux RT is out of the 
> evaluationg
> race. Windows CE should not win :-), it there anyway workaround or hack to 
> fix the issue?

Workaround: Pass-through one of the (typically) many USB host
controllers to the Windows guest (vfio or classic pci-assign). I did
this back then when *HCI emulation was still pretty immature.

But USB device pass-through should also work. Do you happen to pass a
USB 2.0 device via an emulated UHCI? Or are you already using the EHCI
emulation? In the latter case, activating USB tracing (see also
qemu/docs/tracing.txt) and posting the results here may help analysing
the issue.

Jan

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