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

[Frederich, Jens]

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?

My setup:

Ubuntu 64-bit
Windows 7 Embedded Guest
Linux Kernel: 3.10.10-rt7
QEMU: 1.4.0, 1.6.1

thanks,
Jens