[Xen-devel] questions about xen device pass-through.

[Dushmanta Mohapatra <dushmanta.mohapatra@xxxxxxxxx>]

Hello,

I have some doubts/questions regarding device passthrough support in Xen.
I will really appreciate some help/suggestions.

(I am using a Intel Core i5 vPro based Lenovo thinkpad T520 (Intel graphics adapter).
I am running Xen 4.1.1 and PVOPS based Linux 2.6.32.41 kernel as Dom0. I use Windows XP
and Windows 7 as my HVM Domus. lspci details are attached.)

I am trying to achieve the following: Initially allow 
direct access to the primary devices (graphics/ethernet/wireless/USB) to an HVM DomU. After wards,
depending on the need I want to re-assign the direct access of these devices back to Dom0 and
have the DomU access the devices in a virtual manner.

So my question is: Is it possible to do it? Is it possible for VGA/ graphics?

I have tried a few things and following is what I am being able to do:

I am being able to provide direct access to devices (wireless/ethernet/graphics etc) to HVM DomUs.
And also I am being able to dynamically change the direct access to these devices between
the various HVM DomUs (tested with WinXP and Windows 7) in case of ethernet/USB etc. I am being 
able to detach it from one DomU and attach it to another. (This is not working with VGA direct access
though.)

But I am not being able to reattach these devices back to Dom0. I have tried the sysfs way and initial 
boot time passthrough. 

I have also tried the stubdomain way, but when I do not hide the devices
from Dom0 (at boot time) and later try to assign them to stubdomain, my Dom0 gets rebooted automatically. I am following 
the steps mentioned in: http://mirror.choon.net/xen/xen-unstable.hg/docs/misc/vtd.txt

So could some one  tell me if these behaviors are expected or
if I might be doing something wrong. 

I will really appreciate any help. Please let me know if more information is needed from my side.  

Thanks.
Dushmanta

Attachment: pci.txt
Description: Text document

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