Re: [Xen-devel] Q77 IGD instantly crashes on xen-pciback bind.

["Dr. Greg Wettstein" <greg@xxxxxxxxxxxxxxxxx>]

On Nov 23,  4:26pm, Pasi =?iso-8859-1?Q?K=E4rkk=E4inen?= wrote:
} Subject: Re: [Xen-devel] Q77 IGD instantly crashes on xen-pciback bind.

Hi Pasi, hope your week is starting out well, hi to Konrad from Oracle
as well as I see you included him.

> On Fri, Nov 21, 2014 at 02:57:14PM -0600, Dr. Greg Wettstein wrote:
> > Hi, hope the week is ending well for everyone.
> > 
> > As readers of the list may remember we've kept the ATI primary adapter
> > passthrough patches current for qemu-traditional on Xen for a number
> > of years.  Our 'run-passthrough' utility for binding/unbind devices
> > and running a Windows guest with passthrough have enjoyed a tidy
> > number of downloads through the years as well.
> > 
> > We are taking on a passthrough project and in the process upgrading
> > our infrastructure to 4.4.x.  We also need to take on the issue of
> > passing Intel IGD adapters through to a windows guest.  We are
> > currently working on an Intel Q77 (DQ77KB) board in preparation for
> > moving to Q87 boards.
> > 
> > The Intel display adapter is showing up as the standard 00:02.0 PCI
> > device and things go south pretty quickly.  We create a slot for the
> > device on the pciback driver and as soon as we bind the device the
> > machine goes out like a light, no logs or diagnostics, just instantly
> > stone dead.

I'm consolidating your comment from your other response as well so we
keep this on the same thread.

>> As I was walking out the door I remembered I had been delinquent
>> with information.  The dom0 kernel is 32-bit 3.14.22 straight from
>> kernel.org under a 64-bit hypervisor compiled from 4.4.1 sources.

> Wow, quite an old thread :)
>  
> So you're still seeing the same problem with recent Xen/Linux
> versions.. 

Yes, the perils of platforming for 7 year field deployments... :-)

I can certainly build up a toolchain against the HEAD of XEN git and
the most recent release of the kernel if everyone feels that would be
beneficial.

> This might be a stupid question, but here goes anyway: Do you have
> serial console set up? And all the debug/verbose options specified
> for Xen and Linux?

The platform in question doesn't have any serial ports, at least not
surfaced.  We will need to do a bit of wiring if we need to go in that
direction.

Now that I have the machine in a harness in the lab I will stick a
'#define DEBUG 1' in the top of drivers/xen/xen-pciback/pci_stub.c
since that is where the action seems to be going on.

The platform is headed for a measured computing environment so I
thought there may be some type of conflict with tboot holding a
reference to the VGA driver but I verified the issue in a straight
hypervisor boot.

I see that Tiejun Chen from Intel is sorting out issues with respect
to the need to export the ISA bridge into the device emulator in order
to support passthrough on these IGD devices.  I bound the 00:1f.0 ISA
bridge device to pciback and that worked but it did not change the
behavior of the regression.  When the 00:02.0 device is bound to
pciback the display is cleared and the machine dies in its tracks.

I will turn up debugging in pci_stub and see if I can pinpoint where
things blow up, somewhere in pcistub_init_device() I would imagine.

> Thanks,
> 
> -- Pasi

Have a good day.

}-- End of excerpt from Pasi =?iso-8859-1?Q?K=E4rkk=E4inen?=

As always,
Dr. G.W. Wettstein, Ph.D.   Enjellic Systems Development, LLC.
4206 N. 19th Ave.           Specializing in information infra-structure
Fargo, ND  58102            development.
PH: 701-281-1686
FAX: 701-281-3949           EMAIL: greg@xxxxxxxxxxxx
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