diff --git a/test_plans/vswitch_sample_cbdma_test_plan.rst b/test_plans/vswitch_sample_cbdma_test_plan.rst
index c207d842..9402e7cb 100644
--- a/test_plans/vswitch_sample_cbdma_test_plan.rst
+++ b/test_plans/vswitch_sample_cbdma_test_plan.rst
@@ -1,178 +1,235 @@
-.. SPDX-License-Identifier: BSD-3-Clause
-   Copyright(c) 2021 Intel Corporation
+.. Copyright (c) <2021>, Intel Corporation
+   All rights reserved.
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+
+   - Redistributions of source code must retain the above copyright
+     notice, this list of conditions and the following disclaimer.
+
+   - Redistributions in binary form must reproduce the above copyright
+     notice, this list of conditions and the following disclaimer in
+     the documentation and/or other materials provided with the
+     distribution.
+
+   - Neither the name of Intel Corporation nor the names of its
+     contributors may be used to endorse or promote products derived
+     from this software without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+   COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+   INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+   (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+   SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+   STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+   ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+   OF THE POSSIBILITY OF SUCH DAMAGE.
 
 ========================================================
 Vswitch sample test with vhost async data path test plan
 ========================================================
 
-Description
-===========
-
-Vswitch sample can leverage IOAT to accelerate vhost async data-path from dpdk 20.11. This plan test
+Vswitch sample can leverage DMA to accelerate vhost async data-path from dpdk 20.11. This plan test
 vhost DMA operation callbacks for CBDMA PMD and vhost async data-path in vhost sample.
-From 20.11 to 21.02, only split ring support cbdma copy with vhost enqueue direction;
-from 21.05,packed ring also can support cbdma copy with vhost enqueue direction.
+From 22.07, split and packed ring support cbdma copy with both vhost enqueue and deuque direction.
+
+--dmas This parameter is used to specify the assigned DMA device of a vhost device. Async vhost-user
+net driver will be used if --dmas is set. For example –dmas [txd0@00:04.0,txd1@00:04.1,rxd0@00:04.2,rxd1@00:04.3]
+means use DMA channel 00:04.0/00:04.2 for vhost device 0 enqueue/dequeue operation and use DMA channel
+00:04.1/00:04.3 for vhost device 1 enqueue/dequeue operation. The index of the device corresponds to
+the socket file in order, that means vhost device 0 is created through the first socket file,
+vhost device 1 is created through the second socket file, and so on.
+For more about vswitch example, please refer to the DPDK docment:http://doc.dpdk.org/guides/sample_app_ug/vhost.html
 
 Prerequisites
 =============
 
+Hardware
+--------
+Supportted NICs: nic that supports VMDQ
+
+Software
+--------
+Trex:http://trex-tgn.cisco.com/trex/release/v2.26.tar.gz
+
+General set up
+--------------
+1. Compile DPDK and vhost example::
+
+   # CC=gcc meson --werror -Denable_kmods=True -Dlibdir=lib -Dexamples=all --default-library=static x86_64-native-linuxapp-gcc
+   # meson configure -Dexamples=vhost x86_64-native-linuxapp-gcc
+   # ninja -C x86_64-native-linuxapp-gcc -j 110
 
 Test Case1: PVP performance check with CBDMA channel using vhost async driver
-=============================================================================
+-----------------------------------------------------------------------------
+This case tests the basic performance of split ring and packed ring with different packet size when using vhost async drvier.
 
-1. Bind physical port to vfio-pci and CBDMA channel to vfio-pci.
+1. Bind one physical port and 2 CBDMA devices to vfio-pci.
 
 2. On host, launch dpdk-vhost by below command::
 
-	./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 31-32 -n 4 -- \
-	-p 0x1 --mergeable 1 --vm2vm 1 --dma-type ioat --stats 1 --socket-file /tmp/vhost-net --dmas [txd0@0000:00:04.0] --client --total-num-mbufs 600000
+	./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 31-32 -n 4 -a 0000:af:00.0 -a 0000:00:04.0 -a 0000:00:04.1 -- \
+	-p 0x1 --mergeable 1 --vm2vm 1  --stats 1 --socket-file /tmp/vhost-net --dmas [txd0@0000:00:04.0,rxd0@0000:00:04.1] --client --total-num-mbufs 600000
 
 3. Launch virtio-user with packed ring::
 
 	./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 29-30 -n 4 --no-pci --file-prefix=testpmd0 --force-max-simd-bitwidth=512 \
-	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=/tmp/vhost-net,queues=1,mrg_rxbuf=0,in_order=1,vectorized=1,packed_vq=1,server=1 -- -i --rxq=1 --txq=1 --txd=1024 --rxd=1024 --nb-cores=1
+	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=/tmp/vhost-net,queues=1,mrg_rxbuf=0,in_order=1,vectorized=1,packed_vq=1,server=1 \
+	-- -i --rxq=1 --txq=1 --txd=1024 --rxd=1024 --nb-cores=1
 
 4. Start pkts from virtio-user side to let vswitch know the mac addr::
 
 	testpmd>set fwd mac
 	testpmd>start tx_first
 
-5. Inject pkts (packets length=64...1518) separately with dest_mac=virtio_mac_address (specific in above cmd with 00:11:22:33:44:10) to NIC using packet generator, record pvp (PG>nic>vswitch>virtio-user>vswitch>nic>PG) performance number can get expected.
-
-6. Quit and re-launch virtio-user with packed ring size not power of 2::
-
-	./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 29-30 -n 4 --no-pci --file-prefix=testpmd0 --force-max-simd-bitwidth=512 \
-	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=/tmp/vhost-net,queues=1,mrg_rxbuf=0,in_order=1,vectorized=1,packed_vq=1,server=1,queue_size=1025 -- -i --rxq=1 --txq=1 --txd=1025 --rxd=1025 --nb-cores=1
-
-7. Re-test step 4-5, record performance of different packet length.
+5. Inject packets with different packet size[64, 128, 256, 512, 1024, 1280, 1518] and dest_mac=virtio_mac_address (specific in above cmd with 00:11:22:33:44:10) to NIC using packet generator, record pvp (PG>nic>vswitch>virtio-user>vswitch>nic>PG) performance number can get expected.
 
-8. Quit and re-launch virtio-user with split ring::
+6. Quit and re-launch virtio-user with split ring::
 
 	./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 29-30 -n 4 --no-pci --file-prefix=testpmd0 \
 	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=/tmp/vhost-net,queues=1,mrg_rxbuf=0,in_order=1,vectorized=1,server=1 -- -i --rxq=1 --txq=1 --txd=1024 --rxd=1024 --nb-cores=1
 
-9. Re-test step 4-5, record performance of different packet length.
+7. Re-test step 4-5, record performance of different packet length.
 
-Test Case2: PVP test with two VM and two CBDMA channels using vhost async driver
-=================================================================================
+Test Case2: PVP test with two VMs using vhost async driver
+----------------------------------------------------------
+This case tests that the imix packets can forward normally with two VMs in PVP topology when using vhost async drvier, both split ring and packed ring have been covered.
 
-1. Bind one physical ports to vfio-pci and two CBDMA channels to vfio-pci.
+1. Bind one physical ports to vfio-pci and 4 CBDMA devices to vfio-pci.
 
 2. On host, launch dpdk-vhost by below command::
 
-	./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 26-28 -n 4 -- \
-	-p 0x1 --mergeable 1 --vm2vm 1 --dma-type ioat --stats 1 --socket-file /tmp/vhost-net0 --socket-file /tmp/vhost-net1 --dmas [txd0@0000:00:01.0,txd1@0000:00:01.1] --client--total-num-mbufs 600000
+	./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 26-28 -n 4 -a 0000:af:00.0 -a 0000:00:04.0 -a 0000:00:04.1 -a 0000:00:04.2 -a 0000:00:04.3 -- \
+	-p 0x1 --mergeable 1 --vm2vm 1  --stats 1 --socket-file /root/dpdk/vhost-net0 --socket-file /root/dpdk/vhost-net1 --dmas [txd0@0000:00:04.0,rxd0@0000:00:04.1;txd1@0000:00:04.2,rxd1@0000:00:04.3] --client--total-num-mbufs 600000
 
 3. launch two virtio-user ports::
 
 	./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 29-30 -n 4 --no-pci --file-prefix=testpmd0 \
-	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=/tmp/vhost-net0,queues=1,server=1,mrg_rxbuf=1,in_order=0,packed_vq=1 -- -i --rxq=1 --txq=1 --txd=1024 --rxd=1024 --nb-cores=1
+	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=/root/dpdk/vhost-net0,queues=1,server=1,mrg_rxbuf=1,in_order=0,packed_vq=1 -- -i --rxq=1 --txq=1 --txd=1024 --rxd=1024 --nb-cores=1
 	
 	./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 31-32 -n 4 --no-pci --file-prefix=testpmd1 \
-	--vdev=net_virtio_user0,mac=00:11:22:33:44:11,path=/tmp/vhost-net1,queues=1,server=1,mrg_rxbuf=1,in_order=1,vectorized=1 -- -i --rxq=1 --txq=1 --txd=1024 --rxd=1024 --nb-cores=1
+	--vdev=net_virtio_user0,mac=00:11:22:33:44:11,path=/root/dpdk/vhost-net1,queues=1,server=1,mrg_rxbuf=1,in_order=1,vectorized=1 -- -i --rxq=1 --txq=1 --txd=1024 --rxd=1024 --nb-cores=1
 
-4. Start pkts from two virtio-user side individually to let vswitch know the mac addr::
+4. Start packets from two virtio-user side individually to let vswitch know the mac addr::
 
 	testpmd0>set fwd mac
+	testpmd0>start tx_first
 	testpmd1>set fwd mac
 	testpmd1>start tx_first
-	testpmd1>start tx_first
 
 5. Inject IMIX packets (64b...1518b) with dest_mac=virtio_mac_address (00:11:22:33:44:10 and 00:11:22:33:44:11) to NIC using packet generator,record performance number can get expected from Packet generator rx side.
 
-6. Stop dpdk-vhost side and relaunch it with same cmd as step2.
+6. Quit and relaunch dpdk-vhost by below command::
 
-7. Start pkts from two virtio-user side individually to let vswitch know the mac addr::
+	./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 26-28 -n 4 -a 0000:af:00.0 -a 0000:00:04.0 -a 0000:00:04.1 -a 0000:00:04.2 -a 0000:00:04.3  -- \
+	-p 0x1 --mergeable 1 --vm2vm 1  --stats 1 --socket-file /root/dpdk/vhost-net0 --socket-file /root/dpdk/vhost-net1 --dmas [txd0@0000:00:01.0,rxd1@0000:00:01.1] --client--total-num-mbufs 600000
 
-    testpmd0>stop
-    testpmd0>start tx_first
-    testpmd1>stop
-    testpmd1>start tx_first
+7. Start packets from two virtio-user side individually to let vswitch know the mac addr::
 
-8. Inject IMIX packets (64b...1518b) with dest_mac=virtio_mac_address (00:11:22:33:44:10 and 00:11:22:33:44:11) to NIC using packet generator, ensure get same throughput as step5.
+	testpmd0>stop
+	testpmd0>start tx_first
+	testpmd1>stop
+	testpmd1>start tx_first
+
+8.Inject IMIX packets (64b...1518b) to NIC using packet generator, ensure get same throughput as step5.
 
-Test Case3: VM2VM forwarding test with two CBDMA channels
-=========================================================
+Test Case3: VM2VM virtio-user forwarding test using vhost async driver
+----------------------------------------------------------------------
+This case tests that the imix packets can forward normally in VM2VM topology(virtio-user as front-end) when using vhost async drvier, both split ring and packed ring have been covered.
 
-1.Bind one physical ports to vfio-pci and two CBDMA channels to vfio-pci.
+1.Bind one physical port and 4 CBDMA devices to vfio-pci.
 
 2. On host, launch dpdk-vhost by below command::
 
-	./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 26-28 -n 4 -- -p 0x1 --mergeable 1 --vm2vm 1 --dma-type ioat \
-	--socket-file /tmp/vhost-net0 --socket-file /tmp/vhost-net1 --dmas [txd0@0000:00:04.0,txd1@0000:00:04.1]  --client --total-num-mbufs 600000
+	./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 26-28 -n 4 -a 0000:af:00.0 -a 0000:00:04.0 -a 0000:00:04.1 -a 0000:00:04.2 -a 0000:00:04.3 -- -p 0x1 --mergeable 1 --vm2vm 1  \
+	--socket-file /root/dpdk/vhost-net0 --socket-file /root/dpdk/vhost-net1 --dmas [txd0@0000:00:04.0,rxd0@0000:00:04.1;txd1@0000:00:04.2,rxd1@0000:00:04.3]  --client --total-num-mbufs 600000
 
 3. Launch virtio-user::
 
 	./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 29-30 -n 4 --no-pci --file-prefix=testpmd0 \
-	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=/tmp/vhost-net0,queues=1,server=1,mrg_rxbuf=1,in_order=0,packed_vq=1 -- -i --rxq=1 --txq=1 --txd=1024 --rxd=1024 --nb-cores=1
+	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=/root/dpdk/vhost-net0,queues=1,server=1,mrg_rxbuf=1,in_order=0,packed_vq=1 -- -i --rxq=1 --txq=1 --txd=1024 --rxd=1024 --nb-cores=1
 
 	./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 31-32 -n 4 --no-pci --file-prefix=testpmd1 \
-	--vdev=net_virtio_user0,mac=00:11:22:33:44:11,path=/tmp/vhost-net1,queues=1,server=1,mrg_rxbuf=1,in_order=1,vectorized=1 -- -i --rxq=1 --txq=1 --txd=1024 --rxd=1024 --nb-cores=1
+	--vdev=net_virtio_user0,mac=00:11:22:33:44:11,path=/root/dpdk/vhost-net1,queues=1,server=1,mrg_rxbuf=1,in_order=1,vectorized=1 -- -i --rxq=1 --txq=1 --txd=1024 --rxd=1024 --nb-cores=1
 
-4. Loop pkts between two virtio-user sides, record performance number with 64b/2000b/8000b/IMIX pkts can get expected::
+4. Loop packets between two virtio-user sides, record performance number with 64b/2000b/8000b/IMIX pkts can get expected::
 
 	testpmd0>set fwd mac
 	testpmd0>start tx_first
 	testpmd0>stop
 	testpmd0>set eth-peer 0 00:11:22:33:44:11
 	testpmd0>start
+
 	testpmd1>set fwd mac
 	testpmd1>set eth-peer 0 00:11:22:33:44:10
+
 	testpmd1>set txpkts 64
 	testpmd1>start tx_first
 	testpmd1>show port stats all
 	testpmd1>stop
+
 	testpmd1>set txpkts 2000
 	testpmd1>start tx_first
 	testpmd1>show port stats all
 	testpmd1>stop
+
 	testpmd1>set txpkts 2000,2000,2000,2000
 	testpmd1>start tx_first
 	testpmd1>show port stats all
 	testpmd1>stop
+
 	testpmd1>set txpkts 64,256,2000,64,256,2000
 	testpmd1>start tx_first
 	testpmd1>show port stats all
 
-5. Stop dpdk-vhost side and relaunch it with same cmd as step2.
+5. Stop dpdk-vhost side and relaunch it with below command::
+
+	./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 26-28 -n 4 -a 0000:af:00.0 -a 0000:00:04.0 -a 0000:00:04.1 -a 0000:00:04.2 -a 0000:00:04.3 -- -p 0x1 --mergeable 1 --vm2vm 1  \
+	--socket-file /root/dpdk/vhost-net0 --socket-file /root/dpdk/vhost-net1 --dmas [txd0@0000:00:04.0,rxd1@0000:00:04.1]  --client --total-num-mbufs 600000
 
 6. Rerun step 4.
 
-Test Case4: VM2VM test with cbdma channels register/unregister stable check
-============================================================================
+Test Case 4: VM2VM virtio-pmd split ring test with cbdma channels register/unregister stable check
+--------------------------------------------------------------------------------------------------
+This case checks that the split ring with CBDMA channel can work stably when the virtio-pmd port is registed and unregisted for many times.
 
-1. Bind one physical ports to vfio-pci and two CBDMA channels to vfio-pci.
+1. Bind one physical port and 4 CBDMA devices to vfio-pci.
 
 2. On host, launch dpdk-vhost by below command::
 
-    ./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 26-28 -n 4 -- -p 0x1 --mergeable 1 --vm2vm 1 --dma-type ioat \
-    --socket-file /tmp/vhost-net0 --socket-file /tmp/vhost-net1 --dmas [txd0@0000:00:04.0,txd1@0000:00:04.1] --client --total-num-mbufs 600000
+    ./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 26-28 -n 4 -a 0000:af:00.0 -a 0000:80:04.0 -a 0000:00:04.1 -a 0000:00:04.2 -a 0000:00:04.3 -- -p 0x1 --mergeable 1 --vm2vm 1  \
+    --socket-file /root/dpdk/vhost-net0 --socket-file /root/dpdk/vhost-net1 --dmas [txd0@0000:00:04.0,rxd0@0000:00:04.1;txd1@0000:00:01.2,rxd1@0000:00:01.3] --client --total-num-mbufs 600000
 
-3. Start VM0 with qemu-5.2.0::
+3. Start VM0 with qemu::
 
  	qemu-system-x86_64 -name vm1 -enable-kvm -cpu host -smp 4 -m 4096 \
-        -object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge,share=on \
-        -numa node,memdev=mem -mem-prealloc -drive file=/home/osimg/ubuntu20-04.img  \
-        -chardev socket,path=/tmp/vm2_qga0.sock,server,nowait,id=vm2_qga0 -device virtio-serial \
-        -device virtserialport,chardev=vm2_qga0,name=org.qemu.guest_agent.2 -daemonize \
-        -monitor unix:/tmp/vm2_monitor.sock,server,nowait -device e1000,netdev=nttsip1 \
-        -netdev user,id=nttsip1,hostfwd=tcp:127.0.0.1:6002-:22 \
-        -chardev socket,id=char0,path=/tmp/vhost-net0,server \
-        -netdev type=vhost-user,id=netdev0,chardev=char0,vhostforce \
-        -device virtio-net-pci,netdev=netdev0,mac=52:54:00:00:00:01,disable-modern=true,mrg_rxbuf=on,csum=on,guest_csum=on,host_tso4=on,guest_tso4=on,guest_ecn=on -vnc :10
-
-4. Start VM1 with qemu-5.2.0::
+    -object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge,share=on \
+    -numa node,memdev=mem -mem-prealloc -drive file=/home/osimg/ubuntu20-04.img  \
+    -chardev socket,path=/tmp/vm2_qga0.sock,server,nowait,id=vm2_qga0 -device virtio-serial \
+    -device virtserialport,chardev=vm2_qga0,name=org.qemu.guest_agent.2 -daemonize \
+    -monitor unix:/tmp/vm2_monitor.sock,server,nowait -device e1000,netdev=nttsip1 \
+    -netdev user,id=nttsip1,hostfwd=tcp:127.0.0.1:6002-:22 \
+    -chardev socket,id=char0,path=/root/dpdk/vhost-net0,server \
+    -netdev type=vhost-user,id=netdev0,chardev=char0,vhostforce \
+    -device virtio-net-pci,netdev=netdev0,mac=52:54:00:00:00:01,disable-modern=true,mrg_rxbuf=on,csum=on,guest_csum=on,host_tso4=on,guest_tso4=on,guest_ecn=on -vnc :10
+
+4. Start VM1 with qemu::
 
 	qemu-system-x86_64 -name vm2 -enable-kvm -cpu host -smp 4 -m 4096 \
-        -object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge,share=on \
-        -numa node,memdev=mem -mem-prealloc -drive file=/home/osimg/ubuntu20-04-2.img  \
-        -chardev socket,path=/tmp/vm2_qga0.sock,server,nowait,id=vm2_qga0 -device virtio-serial \
-        -device virtserialport,chardev=vm2_qga0,name=org.qemu.guest_agent.2 -daemonize \
-        -monitor unix:/tmp/vm2_monitor.sock,server,nowait -device e1000,netdev=nttsip1 \
-        -netdev user,id=nttsip1,hostfwd=tcp:127.0.0.1:6003-:22 \
-        -chardev socket,id=char0,path=/tmp/vhost-net1,server \
-        -netdev type=vhost-user,id=netdev0,chardev=char0,vhostforce \
-        -device virtio-net-pci,netdev=netdev0,mac=52:54:00:00:00:02,disable-modern=true,mrg_rxbuf=on,csum=on,guest_csum=on,host_tso4=on,guest_tso4=on,guest_ecn=on,packed=on -vnc :12
+    -object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge,share=on \
+    -numa node,memdev=mem -mem-prealloc -drive file=/home/osimg/ubuntu20-04-2.img  \
+    -chardev socket,path=/tmp/vm2_qga0.sock,server,nowait,id=vm2_qga0 -device virtio-serial \
+    -device virtserialport,chardev=vm2_qga0,name=org.qemu.guest_agent.2 -daemonize \
+    -monitor unix:/tmp/vm2_monitor.sock,server,nowait -device e1000,netdev=nttsip1 \
+    -netdev user,id=nttsip1,hostfwd=tcp:127.0.0.1:6003-:22 \
+    -chardev socket,id=char0,path=/root/dpdk/vhost-net1,server \
+    -netdev type=vhost-user,id=netdev0,chardev=char0,vhostforce \
+    -device virtio-net-pci,netdev=netdev0,mac=52:54:00:00:00:02,disable-modern=true,mrg_rxbuf=on,csum=on,guest_csum=on,host_tso4=on,guest_tso4=on,guest_ecn=on -vnc :12
 
 5. Bind virtio port to vfio-pci in both two VMs::
 
@@ -216,43 +273,197 @@ Test Case4: VM2VM test with cbdma channels register/unregister stable check
 	./usertools/dpdk-devbind.py --bind=virtio-pci 00:05.0
 	./usertools/dpdk-devbind.py --bind=vfio-pci 00:05.0
 
-9. Restart vhost, then rerun step 7，check vhost can stable work and get expected throughput.
+9. Quit and relaunch dpdk-vhost with below command::
 
-Test Case5: VM2VM split ring test with iperf and reconnect stable check
-=======================================================================
+    ./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 26-28 -n 4 -a 0000:af:00.0 -a 0000:80:04.0 -a 0000:00:04.1 -a 0000:00:04.2 -a 0000:00:04.3 -- -p 0x1 --mergeable 1 --vm2vm 1  \
+    --socket-file /root/dpdk/vhost-net0 --socket-file /root/dpdk/vhost-net1 --dmas [txd0@0000:00:04.0,rxd1@0000:00:01.3] --client --total-num-mbufs 600000
 
-1. Bind one physical ports to vfio-pci and two CBDMA channels to vfio-pci.
+10. Rerun step 6-7，check vhost can stable work and get expected throughput.
+
+Test Case 5: VM2VM virtio-pmd packed ring test with cbdma channels register/unregister stable check
+---------------------------------------------------------------------------------------------------
+This case checks that the packed ring with CBDMA channel can work stably when the virtio-pmd port is registed and unregisted for many times.
+
+1. Bind one physical port and 4 CBDMA devices to vfio-pci.
 
 2. On host, launch dpdk-vhost by below command::
 
-	./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 26-28 -n 4 -- -p 0x1 --mergeable 1 --vm2vm 1 --dma-type ioat \
-	--socket-file /tmp/vhost-net0 --socket-file /tmp/vhost-net1 --dmas [txd0@0000:00:04.0,txd1@0000:00:04.1] --client --total-num-mbufs 600000
+	./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 26-28 -n 4 -a 0000:af:00.0 -a 0000:80:04.0 -a 0000:00:04.1 -a 0000:00:04.2 -a 0000:00:04.3 -- -p 0x1 --mergeable 1 --vm2vm 1  \
+	--socket-file /root/dpdk/vhost-net0 --socket-file /root/dpdk/vhost-net1 --dmas [txd0@0000:00:04.0,rxd0@0000:00:04.1;txd1@0000:00:04.2,rxd1@0000:00:04.3] --client --total-num-mbufs 600000
+
+3. Start VM0 with qemu::
 
-3. Start VM0 with qemu-5.2.0::
+	qemu-system-x86_64 -name vm1 -enable-kvm -cpu host -smp 4 -m 4096 \
+	-object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge,share=on \
+	-numa node,memdev=mem -mem-prealloc -drive file=/home/osimg/ubuntu20-04.img  \
+	-chardev socket,path=/tmp/vm2_qga0.sock,server,nowait,id=vm2_qga0 -device virtio-serial \
+	-device virtserialport,chardev=vm2_qga0,name=org.qemu.guest_agent.2 -daemonize \
+	-monitor unix:/tmp/vm2_monitor.sock,server,nowait -device e1000,netdev=nttsip1 \
+	-netdev user,id=nttsip1,hostfwd=tcp:127.0.0.1:6002-:22 \
+	-chardev socket,id=char0,path=/root/dpdk/vhost-net0,server \
+	-netdev type=vhost-user,id=netdev0,chardev=char0,vhostforce \
+	-device virtio-net-pci,netdev=netdev0,mac=52:54:00:00:00:01,disable-modern=true,mrg_rxbuf=on,csum=on,guest_csum=on,host_tso4=on,guest_tso4=on,guest_ecn=on,packed=on -vnc :10
+
+4. Start VM1 with qemu::
+
+	qemu-system-x86_64 -name vm2 -enable-kvm -cpu host -smp 4 -m 4096 \
+	-object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge,share=on \
+	-numa node,memdev=mem -mem-prealloc -drive file=/home/osimg/ubuntu20-04-2.img  \
+	-chardev socket,path=/tmp/vm2_qga0.sock,server,nowait,id=vm2_qga0 -device virtio-serial \
+	-device virtserialport,chardev=vm2_qga0,name=org.qemu.guest_agent.2 -daemonize \
+	-monitor unix:/tmp/vm2_monitor.sock,server,nowait -device e1000,netdev=nttsip1 \
+	-netdev user,id=nttsip1,hostfwd=tcp:127.0.0.1:6003-:22 \
+	-chardev socket,id=char0,path=/root/dpdk/vhost-net1,server \
+	-netdev type=vhost-user,id=netdev0,chardev=char0,vhostforce \
+	-device virtio-net-pci,netdev=netdev0,mac=52:54:00:00:00:02,disable-modern=true,mrg_rxbuf=on,csum=on,guest_csum=on,host_tso4=on,guest_tso4=on,guest_ecn=on,packed=on -vnc :12
+
+5. Bind virtio port to vfio-pci in both two VMs::
+
+	modprobe vfio enable_unsafe_noiommu_mode=1
+	modprobe vfio-pci
+	echo 1 > /sys/module/vfio/parameters/enable_unsafe_noiommu_mode
+	./usertools/dpdk-devbind.py --bind=vfio-pci 00:05.0
+
+6. Start testpmd in VMs seperately::
+
+	./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 1-2 -n 4 -- -i --rxq=1 --txq=1 --nb-cores=1 --txd=1024 --rxd=1024
+
+7. Loop packets between two virtio-user sides, record performance number with 64b/2000b/8000b/IMIX pkts can get expected::
+
+	testpmd0>set fwd mac
+	testpmd0>start tx_first
+	testpmd0>stop
+	testpmd0>set eth-peer 0 52:54:00:00:00:02
+	testpmd0>start
+	testpmd1>set fwd mac
+	testpmd1>set eth-peer 0 52:54:00:00:00:01
+	testpmd1>set txpkts 64
+	testpmd1>start tx_first
+	testpmd1>show port stats all
+	testpmd1>stop
+	testpmd1>set txpkts 2000
+	testpmd1>start tx_first
+	testpmd1>show port stats all
+	testpmd1>stop
+	testpmd1>set txpkts 2000,2000,2000,2000
+	testpmd1>start tx_first
+	testpmd1>show port stats all
+	testpmd1>stop
+	testpmd1>set txpkts 64,256,2000,64,256,2000
+	testpmd1>start tx_first
+	testpmd1>show port stats all
+
+8. Quit two testpmd in two VMs, bind virtio-pmd port to virtio-pci,then bind port back to vfio-pci, rerun below cmd 50 times::
+
+	./usertools/dpdk-devbind.py -u 00:05.0
+	./usertools/dpdk-devbind.py --bind=virtio-pci 00:05.0
+	./usertools/dpdk-devbind.py --bind=vfio-pci 00:05.0
+
+9. Rerun step 6-7，check vhost can stable work and get expected throughput.
+
+Test Case 6: VM2VM virtio-net split ring test with 4 cbdma channels and iperf stable check
+------------------------------------------------------------------------------------------
+This case tests with split ring with cbdma channels in two VMs, check that iperf/scp and reconnection can work stably between two virito-net.
+
+1. Bind one physical port and 4 CBDMA devices to vfio-pci.
+
+2. On host, launch dpdk-vhost by below command::
+
+	./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 2-3 -n 4 -a 0000:18:00.0 -a 0000:00:04.0 -a 0000:00:04.1 -a 0000:00:04.2 -a 0000:00:04.3 \
+	-- -p 0x1 --mergeable 1 --vm2vm 1 --socket-file /root/dpdk/vhost-net0 --socket-file /root/dpdk/vhost-net1 --dmas [txd0@0000:00:04.0,rxd0@0000:00:04.1,txd1@0000:00:04.2,rxd1@0000:00:04.3] --client
+
+3. Start VM1 with qemu::
+
+	taskset -c 5,6 /usr/local/qemu-6.2.0/bin/qemu-system-x86_64 -name vm1 -enable-kvm -cpu host -smp 4 -m 4096 \
+    -object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge,share=on \
+    -numa node,memdev=mem -mem-prealloc -drive file=/home/osimg/ubuntu20-04.img  \
+    -chardev socket,path=/tmp/vm2_qga0.sock,server,nowait,id=vm2_qga0 -device virtio-serial \
+    -device virtserialport,chardev=vm2_qga0,name=org.qemu.guest_agent.2 -daemonize \
+    -monitor unix:/tmp/vm2_monitor.sock,server,nowait -device e1000,netdev=nttsip1 \
+    -netdev user,id=nttsip1,hostfwd=tcp:127.0.0.1:6002-:22 \
+    -chardev socket,id=char0,path=/root/dpdk/vhost-net0,server \
+    -netdev type=vhost-user,id=netdev0,chardev=char0,vhostforce \
+    -device virtio-net-pci,netdev=netdev0,mac=52:54:00:00:00:01,disable-modern=true,mrg_rxbuf=off,csum=on,guest_csum=on,host_tso4=on,guest_tso4=on,guest_ecn=on -vnc :10
+
+4. Start VM2 with qemu::
+
+	taskset -c 7,8 /usr/local/qemu-6.2.0/bin/qemu-system-x86_64 -name vm2 -enable-kvm -cpu host -smp 4 -m 4096 \
+    -object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge,share=on \
+    -numa node,memdev=mem -mem-prealloc -drive file=/home/osimg/ubuntu20-04-2.img  \
+    -chardev socket,path=/tmp/vm2_qga0.sock,server,nowait,id=vm2_qga0 -device virtio-serial \
+    -device virtserialport,chardev=vm2_qga0,name=org.qemu.guest_agent.2 -daemonize \
+    -monitor unix:/tmp/vm2_monitor.sock,server,nowait -device e1000,netdev=nttsip1 \
+    -netdev user,id=nttsip1,hostfwd=tcp:127.0.0.1:6003-:22 \
+    -chardev socket,id=char0,path=/root/dpdk/vhost-net1,server \
+    -netdev type=vhost-user,id=netdev0,chardev=char0,vhostforce \
+    -device virtio-net-pci,netdev=netdev0,mac=52:54:00:00:00:02,disable-modern=true,mrg_rxbuf=off,csum=on,guest_csum=on,host_tso4=on,guest_tso4=on,guest_ecn=on -vnc :12
+
+5. On VM1, set virtio device IP and run arp protocal::
+
+    ifconfig ens5 1.1.1.2
+    arp -s 1.1.1.8 52:54:00:00:00:02
+
+6. On VM2, set virtio device IP and run arp protocal::
+
+    ifconfig ens5 1.1.1.8
+    arp -s 1.1.1.2 52:54:00:00:00:01
+
+7. Check the iperf performance between two VMs by below commands::
+
+    Under VM1, run: `iperf -s -i 1`
+    Under VM2, run: `iperf -c 1.1.1.2 -i 1 -t 60`
+
+8. Check iperf throughput can get x Gbits/sec.
+
+9. Scp 1MB file form VM0 to VM1, check packets can be forwarding success by scp::
+
+    Under VM1, run: `scp [xxx] root@1.1.1.8:/`   [xxx] is the file name
+
+10. Relaunch dpdk-vhost, then rerun step 7-9 five times.
+
+11. Relaunch dpdk-vhost by below command::
+
+	./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 2-3 -n 4 -a 0000:af:00.0 -a 0000:80:04.0 -a 0000:00:04.1 -a 0000:00:04.2 -a 0000:00:04.3 \
+	-- -p 0x1 --mergeable 1 --vm2vm 1 --socket-file /root/dpdk/vhost-net0 --socket-file /root/dpdk/vhost-net1 --dmas [txd0@0000:00:04.0,rxd1@0000:00:04.1] --client
+
+12. rerun step 7-9.
+
+Test Case 7: VM2VM virtio-net packed ring test with 4 cbdma channels and iperf stable check
+-------------------------------------------------------------------------------------------
+This case tests with packed ring with 4 cbdma channels in two VMs, check that iperf/scp and reconnection can work stably between two virito-net.
+
+1. Bind one physical ports to vfio-pci and 4 CBDMA devices to vfio-pci.
+
+2. On host, launch dpdk-vhost by below command::
+
+	./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 26-28 -n 4 -a 0000:af:00.0 -a 0000:80:04.0 -a 0000:00:04.1 -a 0000:00:04.2 -a 0000:00:04.3 -- -p 0x1 --mergeable 1 --vm2vm 1 \
+	--socket-file /root/dpdk/vhost-net0 --socket-file /root/dpdk/vhost-net1 --dmas [txd0@0000:00:04.0,rxd0@0000:00:04.1,txd1@0000:00:04.2,rxd1@0000:00:04.3] --total-num-mbufs 600000
+
+3. Start VM1::
 
  	qemu-system-x86_64 -name vm1 -enable-kvm -cpu host -smp 4 -m 4096 \
-        -object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge,share=on \
-        -numa node,memdev=mem -mem-prealloc -drive file=/home/osimg/ubuntu20-04.img  \
-        -chardev socket,path=/tmp/vm2_qga0.sock,server,nowait,id=vm2_qga0 -device virtio-serial \
-        -device virtserialport,chardev=vm2_qga0,name=org.qemu.guest_agent.2 -daemonize \
-        -monitor unix:/tmp/vm2_monitor.sock,server,nowait -device e1000,netdev=nttsip1 \
-        -netdev user,id=nttsip1,hostfwd=tcp:127.0.0.1:6002-:22 \
-        -chardev socket,id=char0,path=/tmp/vhost-net0,server \
-        -netdev type=vhost-user,id=netdev0,chardev=char0,vhostforce \
-        -device virtio-net-pci,netdev=netdev0,mac=52:54:00:00:00:01,disable-modern=true,mrg_rxbuf=off,csum=on,guest_csum=on,host_tso4=on,guest_tso4=on,guest_ecn=on -vnc :10
-
-4. Start VM1 with qemu-5.2.0::
+    -object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge,share=on \
+    -numa node,memdev=mem -mem-prealloc -drive file=/home/osimg/ubuntu20-04.img  \
+    -chardev socket,path=/tmp/vm2_qga0.sock,server,nowait,id=vm2_qga0 -device virtio-serial \
+    -device virtserialport,chardev=vm2_qga0,name=org.qemu.guest_agent.2 -daemonize \
+    -monitor unix:/tmp/vm2_monitor.sock,server,nowait -device e1000,netdev=nttsip1 \
+    -netdev user,id=nttsip1,hostfwd=tcp:127.0.0.1:6002-:22 \
+    -chardev socket,id=char0,path=/root/dpdk/vhost-net0 \
+    -netdev type=vhost-user,id=netdev0,chardev=char0,vhostforce \
+    -device virtio-net-pci,netdev=netdev0,mac=52:54:00:00:00:01,disable-modern=true,mrg_rxbuf=off,csum=on,guest_csum=on,host_tso4=on,guest_tso4=on,guest_ecn=on,packed=on -vnc :10
+
+4. Start VM2::
 
 	qemu-system-x86_64 -name vm2 -enable-kvm -cpu host -smp 4 -m 4096 \
-        -object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge,share=on \
-        -numa node,memdev=mem -mem-prealloc -drive file=/home/osimg/ubuntu20-04-2.img  \
-        -chardev socket,path=/tmp/vm2_qga0.sock,server,nowait,id=vm2_qga0 -device virtio-serial \
-        -device virtserialport,chardev=vm2_qga0,name=org.qemu.guest_agent.2 -daemonize \
-        -monitor unix:/tmp/vm2_monitor.sock,server,nowait -device e1000,netdev=nttsip1 \
-        -netdev user,id=nttsip1,hostfwd=tcp:127.0.0.1:6003-:22 \
-        -chardev socket,id=char0,path=/tmp/vhost-net1,server \
-        -netdev type=vhost-user,id=netdev0,chardev=char0,vhostforce \
-        -device virtio-net-pci,netdev=netdev0,mac=52:54:00:00:00:02,disable-modern=true,mrg_rxbuf=off,csum=on,guest_csum=on,host_tso4=on,guest_tso4=on,guest_ecn=on -vnc :12
+    -object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge,share=on \
+    -numa node,memdev=mem -mem-prealloc -drive file=/home/osimg/ubuntu20-04-2.img  \
+    -chardev socket,path=/tmp/vm2_qga0.sock,server,nowait,id=vm2_qga0 -device virtio-serial \
+    -device virtserialport,chardev=vm2_qga0,name=org.qemu.guest_agent.2 -daemonize \
+    -monitor unix:/tmp/vm2_monitor.sock,server,nowait -device e1000,netdev=nttsip1 \
+    -netdev user,id=nttsip1,hostfwd=tcp:127.0.0.1:6003-:22 \
+    -chardev socket,id=char0,path=/root/dpdk/vhost-net1 \
+    -netdev type=vhost-user,id=netdev0,chardev=char0,vhostforce \
+    -device virtio-net-pci,netdev=netdev0,mac=52:54:00:00:00:02,disable-modern=true,mrg_rxbuf=off,csum=on,guest_csum=on,host_tso4=on,guest_tso4=on,guest_ecn=on,packed=on -vnc :12
 
 5. On VM1, set virtio device IP and run arp protocal::
 
@@ -273,45 +484,46 @@ Test Case5: VM2VM split ring test with iperf and reconnect stable check
 
 9. Scp 1MB file form VM1 to VM2M, check packets can be forwarding success by scp::
 
-     Under VM1, run: `scp [xxx] root@1.1.1.8:/`   [xxx] is the file name
+    Under VM1, run: `scp [xxx] root@1.1.1.8:/`   [xxx] is the file name
 
-10. Relaunch vhost-dpdk, then rerun step 7-9 five times.
+10. Rerun step 7-9 five times.
 
-Test Case6: VM2VM packed ring test with iperf and reconnect stable test
-=======================================================================
+Test Case 8: VM2VM virtio-net packed ring test with 2 cbdma channels and iperf stable check
+-------------------------------------------------------------------------------------------
+This case tests with packed ring with 2 cbdma channels in two VMs, check that iperf/scp and reconnection can work stably between two virito-net.
 
-1. Bind one physical ports to vfio-pci and two CBDMA channels to vfio-pci.
+1. Bind one physical ports to vfio-pci and 2 CBDMA devices to vfio-pci.
 
 2. On host, launch dpdk-vhost by below command::
 
-	./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 26-28 -n 4 -- -p 0x1 --mergeable 1 --vm2vm 1 --dma-type ioat \
-	--socket-file /tmp/vhost-net0 --socket-file /tmp/vhost-net1 --dmas [txd0@0000:00:04.0,txd1@0000:00:04.1] --total-num-mbufs 600000
+	./x86_64-native-linuxapp-gcc/examples/dpdk-vhost -l 26-28 -n 4 -a 0000:af:00.0 -a 0000:80:04.0 -a 0000:00:04.1 -- -p 0x1 --mergeable 1 --vm2vm 1 \
+	--socket-file /root/dpdk/vhost-net0 --socket-file /root/dpdk/vhost-net1 --dmas [txd0@0000:00:04.0,rxd1@0000:00:04.1] --total-num-mbufs 600000
 
-3. Start VM0 with qemu-5.2.0::
+3. Start VM1::
 
  	qemu-system-x86_64 -name vm1 -enable-kvm -cpu host -smp 4 -m 4096 \
-        -object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge,share=on \
-        -numa node,memdev=mem -mem-prealloc -drive file=/home/osimg/ubuntu20-04.img  \
-        -chardev socket,path=/tmp/vm2_qga0.sock,server,nowait,id=vm2_qga0 -device virtio-serial \
-        -device virtserialport,chardev=vm2_qga0,name=org.qemu.guest_agent.2 -daemonize \
-        -monitor unix:/tmp/vm2_monitor.sock,server,nowait -device e1000,netdev=nttsip1 \
-        -netdev user,id=nttsip1,hostfwd=tcp:127.0.0.1:6002-:22 \
-        -chardev socket,id=char0,path=/tmp/vhost-net0 \
-        -netdev type=vhost-user,id=netdev0,chardev=char0,vhostforce \
-        -device virtio-net-pci,netdev=netdev0,mac=52:54:00:00:00:01,disable-modern=true,mrg_rxbuf=off,csum=on,guest_csum=on,host_tso4=on,guest_tso4=on,guest_ecn=on,packed=on -vnc :10
-
-4. Start VM1 with qemu-5.2.0::
+    -object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge,share=on \
+    -numa node,memdev=mem -mem-prealloc -drive file=/home/osimg/ubuntu20-04.img  \
+    -chardev socket,path=/tmp/vm2_qga0.sock,server,nowait,id=vm2_qga0 -device virtio-serial \
+    -device virtserialport,chardev=vm2_qga0,name=org.qemu.guest_agent.2 -daemonize \
+    -monitor unix:/tmp/vm2_monitor.sock,server,nowait -device e1000,netdev=nttsip1 \
+    -netdev user,id=nttsip1,hostfwd=tcp:127.0.0.1:6002-:22 \
+    -chardev socket,id=char0,path=/root/dpdk/vhost-net0 \
+    -netdev type=vhost-user,id=netdev0,chardev=char0,vhostforce \
+    -device virtio-net-pci,netdev=netdev0,mac=52:54:00:00:00:01,disable-modern=true,mrg_rxbuf=off,csum=on,guest_csum=on,host_tso4=on,guest_tso4=on,guest_ecn=on,packed=on -vnc :10
+
+4. Start VM2::
 
 	qemu-system-x86_64 -name vm2 -enable-kvm -cpu host -smp 4 -m 4096 \
-        -object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge,share=on \
-        -numa node,memdev=mem -mem-prealloc -drive file=/home/osimg/ubuntu20-04-2.img  \
-        -chardev socket,path=/tmp/vm2_qga0.sock,server,nowait,id=vm2_qga0 -device virtio-serial \
-        -device virtserialport,chardev=vm2_qga0,name=org.qemu.guest_agent.2 -daemonize \
-        -monitor unix:/tmp/vm2_monitor.sock,server,nowait -device e1000,netdev=nttsip1 \
-        -netdev user,id=nttsip1,hostfwd=tcp:127.0.0.1:6003-:22 \
-        -chardev socket,id=char0,path=/tmp/vhost-net1 \
-        -netdev type=vhost-user,id=netdev0,chardev=char0,vhostforce \
-        -device virtio-net-pci,netdev=netdev0,mac=52:54:00:00:00:02,disable-modern=true,mrg_rxbuf=off,csum=on,guest_csum=on,host_tso4=on,guest_tso4=on,guest_ecn=on,packed=on -vnc :12
+    -object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge,share=on \
+    -numa node,memdev=mem -mem-prealloc -drive file=/home/osimg/ubuntu20-04-2.img  \
+    -chardev socket,path=/tmp/vm2_qga0.sock,server,nowait,id=vm2_qga0 -device virtio-serial \
+    -device virtserialport,chardev=vm2_qga0,name=org.qemu.guest_agent.2 -daemonize \
+    -monitor unix:/tmp/vm2_monitor.sock,server,nowait -device e1000,netdev=nttsip1 \
+    -netdev user,id=nttsip1,hostfwd=tcp:127.0.0.1:6003-:22 \
+    -chardev socket,id=char0,path=/root/dpdk/vhost-net1 \
+    -netdev type=vhost-user,id=netdev0,chardev=char0,vhostforce \
+    -device virtio-net-pci,netdev=netdev0,mac=52:54:00:00:00:02,disable-modern=true,mrg_rxbuf=off,csum=on,guest_csum=on,host_tso4=on,guest_tso4=on,guest_ecn=on,packed=on -vnc :12
 
 5. On VM1, set virtio device IP and run arp protocal::
 
@@ -332,6 +544,6 @@ Test Case6: VM2VM packed ring test with iperf and reconnect stable test
 
 9. Scp 1MB file form VM1 to VM2M, check packets can be forwarding success by scp::
 
-     Under VM1, run: `scp [xxx] root@1.1.1.8:/`   [xxx] is the file name
+    Under VM1, run: `scp [xxx] root@1.1.1.8:/`   [xxx] is the file name
 
 10. Rerun step 7-9 five times.
