WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

[Xen-devel] Memory mapping for PEG/PCIe Graphics Passthrough to <any> Do

To: "'xen-devel@xxxxxxxxxxxxxxxxxxx'" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] Memory mapping for PEG/PCIe Graphics Passthrough to <any> DomU
From: Tim Moore <timothy.moore@xxxxxxxxxxx>
Date: Mon, 30 Mar 2009 14:27:26 +0100
Accept-language: en-US, en-GB
Acceptlanguage: en-US, en-GB
Delivery-date: Fri, 01 May 2009 11:51:08 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcmxO0Q/aM3MpKzvTfOiiZumVOVcYA==
Thread-topic: Memory mapping for PEG/PCIe Graphics Passthrough to <any> DomU

Hi

 

I have been testing xen-unstable.hg (29/03/09) over the past few days .. trying to enable passthrough for VGA.

 

I am using Debian 5.0 (lenny) x64 and compiling from source each time. Tried both linux-2.6.18.8 and linux-2.6.27.5 from Xenbits …

 

Hardware is Nvidia Geforce 8800 512mb GTS PCIe on Intel X58 (ASUS P6T Deluxe) with Core i7 920 CPU.

(had to hack the xen/drviers/pci/passthrough/vtd/dmar.c (line 388) and remove the DMAR bail because of bad RMRR tables.

I also have ATI X300 PCIe for Dom0 Console.

 

Using Xen parameter: iommu=passthrough,pv

Using Dom) parameter: pciback.hide=(‘…’)

 

I compiled pciback as embedded in the kernel and I have tried many different scenarios:

 

1) Nvidia Primary (hidden with pciback.hide= kernel param) (no ATI card installed)

2) ATI Primary, with Nvidia hidden (with pciback.hide= kernel param)

3) all scenarios with pciback as module and using echo devn > /sys/bus/pci/drivers/pciback/new_slot and bind

 

In all scenarios I can successfully see the correct PCI device in the DomU(s), I have tried primarily Windows XP 32bit SP3 and also: linux-2.6.18.8 and linux-2.6.27.5 PV and non PV kernels as DomU and (although I didn’t load a driver) the lspci –vvv showed the devices.

 

Now, I progressed to installing drivers under the Win32 DomU against the Nvidia card, windows correctly identified the device and installed the driver! (latest from nvidia.com). As we all know – Windows wanted a reboot- beforehand a quick check of the device and it has a Yellow exclamation indicating reboot required and resources unavailable.

Reboot and XP starts up … BSOD .. nv4 driver fails .. L

 

Tried with the ATI X300 Primary (no NVidia connected) and went through the same steps. Windows XP now boots without crash although the ATI device still shows a yellow exclamation and insufficient resources.

 

To summarise, pciback functions as expected for PCIe in Dom0 and DomU sees the device. All tools work fine (xm pci-attach / pci-detach / pci-list) and devid show and are managed correctly.

 

I have read all that there is on this subject and have come to the conclusion that this is a problem with qemu-dm and the memory mapping for the new Video device, the Cirrus or stdvga card is always present which I believe may be causing the problem. I have tried nographics=1 but qemu-dm still maps the Video BIOS.

 

Then I noticed that qemu-dm has the new options for “-vga none” .. so I built a wrapper script for qemu-dm to launch with this param. Unfortuntately the DomU doesn’t startup and the qemu log does not show any mention of the Video memory ! so I believe the switch works, but the DomU then fails to boot L

 

To solve this and make it usable I think some development of qemu with regards to the Cirrus VGA and memory management when using more than 1 vga controller is necessary in order to remap the Cirrus or secondary vga adapters in memory correctly. (its also difficult to configure a Windows machine for a second vga when the primary is disabled lol.)

 

Also, I have run strace using a qemu-dm wrapper (very verbose) and analysed the results –nothing seems obvious, but i`m not an expert by far ….

 

Windows has been able to support multiple VGA cards for a long time; I assume that MS is remapping these somehow?

 

I have read in 2 different places that this has worked for others before (without the legacy patch for igfx) and with xen-unstable.hg .. why does it not work for me ?

 

Any help / direction to further debug would be helpful .. I think many people would like to get this one working once and for all!

 

Tim

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
<Prev in Thread] Current Thread [Next in Thread>
  • [Xen-devel] Memory mapping for PEG/PCIe Graphics Passthrough to <any> DomU, Tim Moore <=