PCI-Passthrough without IOMMU possible?



I have an amd-v processor without IOMMU. My operating system is Debian Lenny with a 2.6.30-backports-kernel.
I tried to pass a pci device to a guest operating system but had no success. I thought that should be possible with virtio but I am not sure.
Is it possible? Or do I need an iommu like vt-d or amd-vi?
If it is possible: which kernel version do I need for that?