SR-IOV problems - HVM cannot access network

[David White <dwhite@speakeasy.net>]

Hi all,

I am having problems getting SR-IOV functions to work in my HVMs.  My 
hardware has VT-d support, and pci passthrough works fine for physical 
functions.  In a nutshell here is the current state:

Dom0 :  NICs are 2-port 82576.  I can get full network access using 
either PF or VF interfaces.
HVM : PCI passthrough of physical functions work -- full network access
HVM : PCI passthrough of virtual functions fail -- can send pkts but 
cannot receive.

The best lead I have right now is evident from the qemu logs.

when PF (04:00.0) is assigned to HVM:

pt_msix_init: get MSI-X table bar base fafbc000
pt_msix_init: table_off = 0, total_entries = 10
pt_msix_init: errno = 2
pt_msix_init: mapping physical MSI-X table to 7f23a03d5000
pt_msi_setup: msi mapped with pirq 37
pci_intx: intx=1
register_real_device: Real physical device 04:00.0 registered successfuly!
IRQ type = MSI-INTx

when VF (04:10.2) is assigned to HVM:

pt_msix_init: get MSI-X table bar base fae24000
pt_msix_init: table_off = 0, total_entries = 3
pt_msix_init: errno = 2
pt_msix_init: mapping physical MSI-X table to 7fc918846000
register_real_device: Real physical device 04:10.2 registered successfuly!
IRQ type = INTx

VFs don't seem to be using MSI/MSI-X interupts.  Does this indicate a 
problem?

Can anyone give some insight on this?
thanks  - david