default value is 15.
**--dequeue-zero-copy**
-Dequeue zero copy will be enabled when this option is given.
+Dequeue zero copy will be enabled when this option is given. it is worth to
+note that if NIC is binded to driver with iommu enabled, dequeue zero copy
+cannot work at VM2NIC mode (vm2vm=0) due to currently we don't setup iommu
+dma mapping for guest memory.
**--vlan-strip 0|1**
VLAN strip option is removed, because different NICs have different behaviors
* Failed to build DPDK in VM
Make sure "-cpu host" QEMU option is given.
+
+* Device start fails if NIC's max queues > the default number of 128
+
+ mbuf pool size is dependent on the MAX_QUEUES configuration, if NIC's
+ max queue number is larger than 128, device start will fail due to
+ insufficient mbuf.
+
+ Change the default number to make it work as below, just set the number
+ according to the NIC's property. ::
+
+ make EXTRA_CFLAGS="-DMAX_QUEUES=320"