Bug in PCI Passthrough?

Bug in PCI Passthrough?

[Josef Vogt]

Hello all

I tried to enable PCI Passthrough in my Debian Squeeze installation. 
Unfortunately, it didnt work. The following bug showed up (excerpt from 
dmesg):

[ 10.148612] uhci_hcd 0000:00:14.2: PCI INT D -> Link[LNKD] -> GSI 11
(level, low) -> IRQ 11
[ 4.678352] Failed to setup GSI :11, err_code:-22
[ 4.678480] dmfe 0000:00:0e.0: PCI INT A -> Link[LNKB] -> GSI 11 (level,
low) -> IRQ 11
[ 6.868419] Failed to setup GSI :10, err_code:-22

Strange thing is, it worked perfectly with Debian Lenny Kernel 2.6.26 [1]

I first thought, it was a Debian bug[2], but then I tried the vanilla 
kernel (xen/stable-2.6.32.x from kernel.org) the bug was exactly the 
same. See also [1] for the the exact error messages.
I also tried to get help from xen users list [3].
Strange side note: It seems to work with opensuse 11.2 (kernel 3.6.31) 
and also Opensuse 11.3 (kernel 3.6.34) – I installed them both but didnt 
get the above error message. The interrupts were assigned correctly. So 
i started looking at the code, but the used code in Opensuse looks quite 
different to the xen code in kernel.org. (I didn't find xen.c, where the 
error message „Failed to setup GSI“ is located). Is it possible that 
Opensuse uses Xen source code from an older branch?
I also compiled xen/next-2.6.39 (up to this commit: 
6f3ba85fbef08ce0d833a1943827454b3e5532b7) but then, unfortunately the 
dom0 crashes.

All the above together (except the dom0 crash in 2.6.39, of course) 
let's me think, this could a bug in xen source code.
Greetings!
Josef

[1] http://lists.xensource.com/archives/html/xen-users/2011-01/msg00411.html
[2] http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=610832
[3] http://lists.xensource.com/archives/html/xen-users/2011-01/msg00388.html

Re: Bug in PCI Passthrough?

[Pasi Kärkkäinen]

On Tue, Apr 19, 2011 at 09:51:32PM +0200, Josef Vogt wrote:
> Hello all
>
> I tried to enable PCI Passthrough in my Debian Squeeze installation.  
> Unfortunately, it didnt work. The following bug showed up (excerpt from  
> dmesg):
>
> [ 10.148612] uhci_hcd 0000:00:14.2: PCI INT D -> Link[LNKD] -> GSI 11
> (level, low) -> IRQ 11
> [ 4.678352] Failed to setup GSI :11, err_code:-22
> [ 4.678480] dmfe 0000:00:0e.0: PCI INT A -> Link[LNKB] -> GSI 11 (level,
> low) -> IRQ 11
> [ 6.868419] Failed to setup GSI :10, err_code:-22
>
> Strange thing is, it worked perfectly with Debian Lenny Kernel 2.6.26 [1]
>
> I first thought, it was a Debian bug[2], but then I tried the vanilla  
> kernel (xen/stable-2.6.32.x from kernel.org) the bug was exactly the  
> same. See also [1] for the the exact error messages.
> I also tried to get help from xen users list [3].
> Strange side note: It seems to work with opensuse 11.2 (kernel 3.6.31)  
> and also Opensuse 11.3 (kernel 3.6.34) ??? I installed them both but 
> didnt get the above error message. The interrupts were assigned 
> correctly. So i started looking at the code, but the used code in 
> Opensuse looks quite different to the xen code in kernel.org. (I didn't 
> find xen.c, where the error message ???Failed to setup GSI??? is 
> located). Is it possible that Opensuse uses Xen source code from an older 
> branch?
>

Novell/SLES/Opensuse xen kernels are based on the traditional xenlinux patches,
while upstream kernel.org (and xen.git) has the new pvops-based xen support.

The traditional xenlinux patches will never be merged to upstream Linux,
so users and vendors should focus on the pvops Xen code nowadays..

-- Pasi

> I also compiled xen/next-2.6.39 (up to this commit:  
> 6f3ba85fbef08ce0d833a1943827454b3e5532b7) but then, unfortunately the  
> dom0 crashes.
>
> All the above together (except the dom0 crash in 2.6.39, of course)  
> let's me think, this could a bug in xen source code.
> Greetings!
> Josef
>
> [1] http://lists.xensource.com/archives/html/xen-users/2011-01/msg00411.html
> [2] http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=610832
> [3] http://lists.xensource.com/archives/html/xen-users/2011-01/msg00388.html
>
>
>
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