Re: PCI/VGA passthrough on >Xen-4.2 - (XEN) AMD-Vi: IO_PAGE_FAULT:

[Hans Mueller <mcbeagle@gmx.de>]

On Thursday, 8. November 2012 20:02:51 feral wrote:
> Upgraded from Xen-4.1 to 4.2/4.3/4.3-unstable.  Tested against all three.
> 
> VGA passthrough previously working with 4.1 is no longer working with >4.2.
> 
> Setup - Working:
> Mint13, kernel-3.2.0-32, Xen-4.1 (from Ubuntu-Precise repos), libvirt-bin,
> xend
> Asus Radeon HD 7870 DirectCU.
> Works perfect.  Benches on par with bare metal.
> 
> Setup - Broken:
> Mint13, kernel-3.2.0-32, Xen-4.2,Xen-4.3,Xen-4.3-unstable (from GIT), xl
> toolstack.
> Asus Radeon HD 7870 DirectCU.
> Some times the guest boots correctly but display is never enabled.
>  Sometimes BSOD, doesn't seem to be any rhyme or reason?
> 
> No errors in logs.   Found the following in 'xl dmesg':
> (XEN) AMD-Vi: IO_PAGE_FAULT: domain = 2, device id = 0x600, fault address =
> 0x1ac800000, flags = 0

I had a similar problem since hg revision 25818:50adc933faaf which changes the 
qemu tag.
It looks like the qemu commit 
3e66da7266c84638c0e22a09c9d2b07529802576 
(qemu-xen-trad: fix msi_translate with PV event delivery) 
causes this behavior.

I solved the problem for me by using 'pci_msitranslate=0' in the domU config.
In addition I had to reboot (perhaps poweroff?) the dom0 once the IO_PAGE_FAULT 
occured.

Regards
Hans