PCI passthrough

Hi all -

I'm trying to PCI passthrough a Digium TDM card (Tiger Jet Network Inc. Tiger3XX Modem/ISDN interface) used for a PBX (asterisk). I'm not having any luck and thought I'd post here to see if this is even capable of working. I'm using a host kernel 2.6.30.6-53 (built from a F11 source rpm). I've compiled qemu-kvm 10.6, libvirt 0.7.1-1, and tried kvm in the 2.6.30.6-53 kernel and kvm-kmod-2.6.30.1. When starting the VM, pci-stub binds to the card, and the guest can "see" the card (lspci -v). But when the zaptel/dahdi drivers try to init (in the guest), I get this:

#modprobe wctdm

Sep 23 19:47:45 test kernel: dahdi: Telephony Interface Registered on major 196
Sep 23 19:47:45 test kernel: dahdi: Version: 2.2.0.2
Sep 23 19:47:45 test kernel: wctdm 0000:00:07.0: PCI INT A -> Link[LNKC] -> GSI 10 (level, high) -> IRQ 10
Sep 23 19:47:46 test kernel: TDM PCI Master abort
Sep 23 19:47:46 test kernel: Freshmaker version: ff
Sep 23 19:47:46 test kernel: 00 != ff
Sep 23 19:47:46 test kernel: 01 != ff
Sep 23 19:47:46 test kernel: 02 != ff
...lots of these...
Sep 23 19:47:46 test kernel: fd != ff
Sep 23 19:47:46 test kernel: fe != ff
Sep 23 19:47:46 test kernel: Freshmaker failed register test
Sep 23 19:47:46 test kernel: TDM PCI Master abort
Sep 23 19:47:47 test kernel: wctdm: probe of 0000:00:07.0 failed with error -5

For guests, I've tried both Centos 5.3 and Fedora 11. Both behave exactly the same (and both are using virtio_net/pci).

Something I've also noticed is that once pci-stub binds and then unbinds to the card, the HOST behaves exactly the same (same exact errors when modprobe wctdm). The only way I can get the HOST drivers to work (after unbind pci-stub) is to remove the pci card from the bus, then rescan the bus to bring it back. This allows the HOST drivers to work, but this trick does not work in the guest.

echo "1" > /sys/bus/pci/devices/0000\:03\:00.0/remove echo "1" > /sys/bus/pci/rescan

If anybody has any ideas I can try, I'd surely appreciate it. My host does NOT have vt-d capable hardware, and I'm not even sure that is requirement - is it? Host is an Intel ICH10/P45/Q6600.

Thanks - Matt

----------------
lspci -v for the HOST
03:00.0 Communication controller: Tiger Jet Network Inc. Tiger3XX Modem/ISDN interface
Subsystem: Device b119:0003
Flags: bus master, medium devsel, latency 64, IRQ 20
I/O ports at d000 [size=256]
[virtual] Memory at f4000000 (32-bit, non-prefetchable) [size=4K]
Capabilities: [40] Power Management version 2
Kernel driver in use: pci-stub
Kernel modules: hisax, wctdm

lspci -v the the GUEST:

00:07.0 Communication controller: Tiger Jet Network Inc. Tiger3XX Modem/ISDN interface
Subsystem: Device b119:0003
Physical Slot: 7
Flags: bus master, medium devsel, latency 64, IRQ 10
I/O ports at c300 [size=256]
Memory at f2001000 (32-bit, non-prefetchable) [size=4K]
Kernel modules: wctdm, hisax

"bus master" means the card can dma, which requires an iommu.

Do not meddle in the internals of kernels, for they are subtle and quick to panic.

Thanks for the info -- At least I know I can stop pulling my hair out now.