Hi All,

I am using iommu to receive packets both from hypervisor and from VM. KVM is used for the virtualization. However, after I deliver the kernel options (iommu and pci realloc), I can not receive packets in hypervisor, but VF works fine in VM. When I tried to receive packets in hypervisor, dmesg shows the following:

ixgbe 0000:03:00.1: complete
ixgbe 0000:03:00.1: PCI INT A disabled
igb_uio 0000:03:00.1: PCI INT A -> GSI 38 (level, low) -> IRQ 38
igb_uio 0000:03:00.1: setting latency timer to 64
igb_uio 0000:03:00.1: irq 87 for MSI/MSI-X
uio device registered with irq 57
DRHD: handling fault status reg 2
DMAR:[DMA Read] Request device [03:00.1] fault addr b9d0f000
DMAR:[fault reason 02] Present bit in context entry is clear

03:00.1 Ethernet controller: Intel Corporation 82599EB 10 Gigabit Dual Port Backplane Connection (rev 01)
Subsystem: Intel Corporation Ethernet X520 10GbE Dual Port KX4-KR Mezz
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort+ >SERR- <PERR- INTx-
Latency: 0, Cache Line Size: 64 bytes
Interrupt: pin A routed to IRQ 38
Region 0: Memory at d9400000 (64-bit, prefetchable) [size=4M]
Region 2: I/O ports at ece0 [size=32]
Region 4: Memory at d9bfc000 (64-bit, prefetchable) [size=16K]
Expansion ROM at <ignored> [disabled]
Capabilities: <access denied>
Kernel driver in use: igb_uio
Kernel modules: ixgbe

We can see those addresses are not matched. So the kernel got fault. I am wondering why this happens?