[dts][PATCH V2 2/3] test_plans/loopback_virtio_user_server_mode_cbdma_test_plan: add loopback_virtio_user_server_mode_cbdma test_plan

[dts][PATCH V2 2/3] test_plans/loopback_virtio_user_server_mode_cbdma_test_plan: add loopback_virtio_user_server_mode_cbdma test_plan

[Wei Ling]

v1:
As commit 53d3f4778c(vhost: integrate dmadev in asynchronous data-path),
add new testsuite loopback_virtio_user_server_mode_cbdma for coverage the
loopback virtio-user server mode with cbdma.
1) Add new testplan loopback_virtio_user_server_mode_cbdma_test_plan into
   test_plans.

v2:
Modify the `Description` content in loopback_virtio_user_server_mode_cbdma_test_plan.

Signed-off-by: Wei Ling <weix.ling@intel.com>
---
 ...irtio_user_server_mode_cbdma_test_plan.rst | 385 ++++++++++++++++++
 1 file changed, 385 insertions(+)
 create mode 100644 test_plans/loopback_virtio_user_server_mode_cbdma_test_plan.rst

diff --git a/test_plans/loopback_virtio_user_server_mode_cbdma_test_plan.rst b/test_plans/loopback_virtio_user_server_mode_cbdma_test_plan.rst
new file mode 100644
index 00000000..97ab202a
--- /dev/null
+++ b/test_plans/loopback_virtio_user_server_mode_cbdma_test_plan.rst
@@ -0,0 +1,385 @@
+.. Copyright (c) <2022>, 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 NOgit T 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.
+
+============================================================
+Loopback vhost/virtio-user server mode with CBDMA test plan
+============================================================
+
+Description
+===========
+
+Vhost asynchronous data path leverages DMA devices to offload memory copies from the CPU and it is implemented in an asynchronous way.
+In addition, vhost supports M:N mapping between vrings and DMA virtual channels. Specifically, one vring can use multiple different DMA
+channels and one DMA channel can be shared by multiple vrings at the same time. Vhost enqueue operation with CBDMA channels is supported 
+in both split and packed ring.
+
+This document provides the test plan for testing the following features when Vhost-user using asynchronous data path with
+CBDMA channels in loopback virtio-user topology.
+1. Virtio-user server mode is a feature to enable virtio-user as the server, vhost as the client, thus after vhost-user is killed then relaunched,
+virtio-user can reconnect back to vhost-user again; at another hand, virtio-user also can reconnect back to vhost-user after virtio-user is killed.
+This feature test need cover different rx/tx paths with virtio 1.0 and virtio 1.1, includes split ring mergeable, non-mergeable, inorder mergeable,
+inorder non-mergeable, vector_rx path and packed ring mergeable, non-mergeable, inorder non-mergeable, inorder mergeable, vectorized path.
+2. Check payload valid after packets forwarding many times.
+3. Stress test with large chain packets.
+
+Note:
+1. When DMA devices are bound to vfio driver, VA mode is the default and recommended. For PA mode, page by page mapping may
+exceed IOMMU's max capability, better to use 1G guest hugepage.
+2. DPDK local patch that about vhost pmd is needed when testing Vhost asynchronous data path with testpmd.
+
+For more about dpdk-testpmd sample, please refer to the DPDK docments:
+https://doc.dpdk.org/guides/testpmd_app_ug/run_app.html
+For virtio-user vdev parameter, you can refer to the DPDK docments:
+https://doc.dpdk.org/guides/nics/virtio.html#virtio-paths-selection-and-usage.
+
+Prerequisites
+=============
+
+Topology
+--------
+Test flow: Virtio-user-->Vhost-user-->Testpmd-->Vhost-user-->Virtio-user
+
+General set up
+--------------
+1. Compile DPDK::
+
+      # CC=gcc meson --werror -Denable_kmods=True -Dlibdir=lib -Dexamples=all --default-library=<dpdk build dir>
+      # ninja -C <dpdk build dir> -j 110
+      For example:
+      CC=gcc meson --werror -Denable_kmods=True -Dlibdir=lib -Dexamples=all --default-library=x86_64-native-linuxapp-gcc
+      ninja -C x86_64-native-linuxapp-gcc -j 110
+
+2. Get the PCI device ID and DMA device ID of DUT, for example, 0000:18:00.0 is PCI device ID, 0000:00:04.0, 0000:00:04.1 is DMA device ID::
+
+      <dpdk dir># ./usertools/dpdk-devbind.py -s
+
+      Network devices using kernel driver
+      ===================================
+      0000:18:00.0 'Device 159b' if=ens785f0 drv=ice unused=vfio-pci
+
+      DMA devices using kernel driver
+      ===============================
+      0000:00:04.0 'Sky Lake-E CBDMA Registers 2021' drv=ioatdma unused=vfio-pci
+      0000:00:04.1 'Sky Lake-E CBDMA Registers 2021' drv=ioatdma unused=vfio-pci
+
+Test case
+=========
+
+Common steps
+------------
+1. Bind 1 NIC port and CBDMA channels to vfio-pci::
+
+      <dpdk dir># ./usertools/dpdk-devbind.py -b vfio-pci <DUT port pci device id>
+      <dpdk dir># ./usertools/dpdk-devbind.py -b vfio-pci <DUT port DMA device id>
+
+      For example, bind 2 CBDMA channels:
+      <dpdk dir># ./usertools/dpdk-devbind.py -b vfio-pci 0000:00:04.0,0000:00:04.1
+
+Test Case 1: loopback packed ring all path cbdma test payload check with server mode and multi-queues
+-----------------------------------------------------------------------------------------------------
+This case tests the payload is valid after forwading large chain packets in loopback vhost-user/virtio-user packed ring
+all path multi-queues with server mode when vhost uses the asynchronous enqueue operations with CBDMA channels. Both 
+iova as VA and PA mode test.
+
+1. Bind 8 CBDMA channel to vfio-pci, as common step 1.
+
+2. Launch vhost by below command::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 10-18 -n 4 \
+	-a 0000:00:04.0 -a 0000:00:04.1 -a 0000:00:04.2 -a 0000:00:04.3 -a 0000:00:04.4 -a 0000:00:04.5 -a 0000:00:04.6 -a 0000:00:04.7 \
+	--vdev 'eth_vhost0,iface=vhost-net0,queues=8,client=1,dmas=[txq0;txq1;txq2;txq3;txq4;txq6;txq7]' \
+	--iova=va -- -i --nb-cores=5 --rxq=8 --txq=8 --txd=1024 --rxd=1024 \
+	--lcore-dma=[lcore11@0000:00:04.0,lcore11@0000:00:04.7,lcore12@0000:00:04.1,lcore12@0000:00:04.2,lcore12@0000:00:04.3,lcore13@0000:00:04.2,lcore13@0000:00:04.3,lcore13@0000:00:04.4,lcore14@0000:00:04.2,lcore14@0000:00:04.3,lcore14@0000:00:04.4,lcore14@0000:00:04.5,lcore15@0000:00:04.0,lcore15@0000:00:04.1,lcore15@0000:00:04.2,lcore15@0000:00:04.3,lcore15@0000:00:04.4,lcore15@0000:00:04.5,lcore15@0000:00:04.6,lcore15@0000:00:04.7]
+
+3. Launch virtio-user with packed ring mergeable inorder path::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 30,31 -n 4 --file-prefix=virtio-user0 --no-pci \
+	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=./vhost-net0,queues=8,mrg_rxbuf=1,in_order=1,packed_vq=1,server=1 \
+	-- -i --nb-cores=1 --rxq=8 --txq=8 --txd=1024 --rxd=1024
+	testpmd>set fwd csum
+	testpmd>start
+
+4. Attach pdump secondary process to primary process by same file-prefix::
+
+    <dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-pdump -v --file-prefix=virtio-user0 -- \
+    --pdump 'device_id=net_virtio_user1,queue=0,rx-dev=./pdump-virtio-rx-q0.pcap,mbuf-size=8000' \
+    --pdump 'device_id=net_virtio_user1,queue=1,rx-dev=./pdump-virtio-rx-q1.pcap,mbuf-size=8000'
+
+5. Send large pkts from vhost, check loopback performance can get expected and each queue can receive packets::
+
+	testpmd> set fwd csum
+	testpmd> set txpkts 64,64,64,2000,2000,2000
+	testpmd> set burst 1
+	testpmd> start tx_first 1
+	testpmd> stop
+
+6. Quit pdump, check all the packets length are 6192 Byte and the payload in receive packets are same in each pcap file.
+
+7. Quit and relaunch vhost and rerun step 4-6.
+
+8. Quit and relaunch virtio with packed ring mergeable path as below::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 30,31 -n 4 --file-prefix=virtio-user0 --no-pci \
+	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=./vhost-net0,queues=8,mrg_rxbuf=1,in_order=0,packed_vq=1,server=1 \
+	-- -i --nb-cores=1 --rxq=8 --txq=8 --txd=1024 --rxd=1024
+	testpmd>set fwd csum
+	testpmd>start
+
+9. Rerun steps 4-7.
+
+10. Quit and relaunch virtio with packed ring non-mergeable path as below::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 30,31 -n 4 --file-prefix=virtio-user0 --no-pci \
+	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=./vhost-net0,queues=8,mrg_rxbuf=0,in_order=0,packed_vq=1,server=1 \
+	-- -i --nb-cores=1 --rxq=8 --txq=8 --txd=1024 --rxd=1024
+	testpmd>set fwd csum
+	testpmd>start
+
+11. Rerun step 4.
+
+12. Send pkts from vhost, check loopback performance can get expected and each queue can receive packets::
+
+	testpmd> set fwd csum
+	testpmd> set txpkts 64,128,256,512
+	testpmd> set burst 1
+	testpmd> start tx_first 1
+	testpmd> stop
+
+13. Quit pdump, check all the packets length are 960 Byte and the payload in receive packets are same in each pcap file.
+
+14. Quit and relaunch vhost and rerun step 11-13.
+
+15. Quit and relaunch virtio with packed ring inorder non-mergeable path as below::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 30,31 -n 4 --file-prefix=virtio-user0 --no-pci \
+	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=./vhost-net0,queues=8,mrg_rxbuf=0,in_order=1,packed_vq=1,server=1 \
+	-- -i --nb-cores=1 --rxq=8 --txq=8 --txd=1024 --rxd=1024
+	testpmd>set fwd csum
+	testpmd>start
+
+16. Rerun step 11-14.
+
+17. Quit and relaunch virtio with packed ring vectorized path as below::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 30,31 -n 4 --file-prefix=virtio-user0 --no-pci --force-max-simd-bitwidth=512 \
+	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=./vhost-net0,queues=8,mrg_rxbuf=0,in_order=1,packed_vq=1,vectorized=1,server=1 \
+	-- -i --nb-cores=1 --rxq=8 --txq=8 --txd=1024 --rxd=1024
+	testpmd>set fwd csum
+	testpmd>start
+
+18. Rerun step 11-14.
+
+19. Quit and relaunch virtio with packed ring vectorized path and ring size is not power of 2 as below::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 30,31 -n 4 --file-prefix=virtio-user0 --no-pci --force-max-simd-bitwidth=512 \
+	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=./vhost-net0,queues=8,mrg_rxbuf=0,in_order=1,packed_vq=1,vectorized=1,queue_size=1025,server=1 \
+	-- -i --nb-cores=1 --rxq=8 --txq=8 --txd=1025 --rxd=1025
+	testpmd>set fwd csum
+	testpmd>start
+
+20. Rerun step 11-14.
+
+21. Quit and relaunch vhost w/ iova=pa::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 10-18 -n 4 \
+	-a 0000:00:04.0 -a 0000:00:04.1 -a 0000:00:04.2 -a 0000:00:04.3 -a 0000:00:04.4 -a 0000:00:04.5 -a 0000:00:04.6 -a 0000:00:04.7 \
+	--vdev 'eth_vhost0,iface=vhost-net0,queues=8,client=1,dmas=[txq0;txq1;txq2;txq3;txq4;txq6;txq7]' \
+	--iova=pa -- -i --nb-cores=5 --rxq=8 --txq=8 --txd=1024 --rxd=1024 \
+	--lcore-dma=[lcore11@0000:00:04.0,lcore11@0000:00:04.7,lcore12@0000:00:04.1,lcore12@0000:00:04.2,lcore12@0000:00:04.3,lcore13@0000:00:04.2,lcore13@0000:00:04.3,lcore13@0000:00:04.4,lcore14@0000:00:04.2,lcore14@0000:00:04.3,lcore14@0000:00:04.4,lcore14@0000:00:04.5,lcore15@0000:00:04.0,lcore15@0000:00:04.1,lcore15@0000:00:04.2,lcore15@0000:00:04.3,lcore14@0000:00:04.4,lcore14@0000:00:04.5,lcore15@0000:00:04.6,lcore15@0000:00:04.7]
+
+22. Rerun steps 3-6.
+
+Test Case 2: loopback split ring all path cbdma test payload check with server mode and multi-queues
+----------------------------------------------------------------------------------------------------
+This case tests the payload is valid after forwading large chain packets in loopback vhost-user/virtio-user split ring
+all path multi-queues with server mode when vhost uses the asynchronous enqueue operations with CBDMA channels. Both
+iova as VA and PA mode test.
+
+1. Bind 3 CBDMA channel to vfio-pci, as common step 1.
+
+2. Launch vhost by below command::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 10-18 -n 4 -a 0000:00:04.0 -a 0000:00:04.1 -a 0000:00:04.2 \
+	--vdev 'eth_vhost0,iface=vhost-net0,queues=8,client=1,dmas=[txq0;txq1;txq2;txq3;txq4;txq5;txq6]' \
+	--iova=va -- -i --nb-cores=5 --rxq=8 --txq=8 --txd=1024 --rxd=1024 \
+	--lcore-dma=[lcore11@0000:00:04.0,lcore12@0000:00:04.0,lcore13@0000:00:04.1,lcore13@0000:00:04.2,lcore14@0000:00:04.1,lcore14@0000:00:04.2,lcore15@0000:00:04.1,lcore15@0000:00:04.2]
+
+3. Launch virtio-user with split ring mergeable inorder path::
+
+	dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 30,31 -n 4 --file-prefix=virtio-user0 --no-pci \
+	-vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=./vhost-net0,queues=8,mrg_rxbuf=1,in_order=1,server=1 \
+	- -i --nb-cores=1 --rxq=8 --txq=8 --txd=1024 --rxd=1024
+	testpmd>set fwd csum
+	testpmd>start
+
+4. Attach pdump secondary process to primary process by same file-prefix::
+
+    <dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-pdump -v --file-prefix=virtio-user0 -- \
+    --pdump 'device_id=net_virtio_user1,queue=0,rx-dev=./pdump-virtio-rx-q0.pcap,mbuf-size=8000' \
+    --pdump 'device_id=net_virtio_user1,queue=1,rx-dev=./pdump-virtio-rx-q1.pcap,mbuf-size=8000'
+
+5. Send large pkts from vhost, check loopback performance can get expected and each queue can receive packets::
+
+	testpmd> set fwd csum
+	testpmd> set txpkts 64,64,64,2000,2000,2000
+	testpmd> set burst 1
+	testpmd> start tx_first 1
+	testpmd> stop
+
+6. Quit pdump, check all the packets length are 6192 Byte and the payload in receive packets are same in each pcap file.
+
+7. Quit and relaunch vhost and rerun step 4-6.
+
+8. Quit and relaunch virtio with split ring mergeable path as below::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 30,31 -n 4 --file-prefix=virtio-user0 --no-pci \
+	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=./vhost-net0,queues=8,mrg_rxbuf=1,in_order=0,server=1 \
+	-- -i --nb-cores=1 --rxq=8 --txq=8 --txd=1024 --rxd=1024
+	testpmd>set fwd csum
+	testpmd>start
+
+9. Rerun steps 4-7.
+
+10. Quit and relaunch virtio with split ring non-mergeable path as below::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 30,31 -n 4 --file-prefix=virtio-user0 --no-pci \
+	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=./vhost-net0,queues=8,mrg_rxbuf=0,in_order=0,server=1 \
+	-- -i --enable-hw-vlan-strip --nb-cores=1 --rxq=8 --txq=8 --txd=1024 --rxd=1024
+	testpmd>set fwd csum
+	testpmd>start
+
+11. Rerun step 4.
+
+12. Send pkts from vhost, check loopback performance can get expected and each queue can receive packets::
+
+	testpmd> set fwd csum
+	testpmd> set txpkts 64,128,256,512
+	testpmd> set burst 1
+	testpmd> start tx_first 1
+	testpmd> stop
+
+13. Quit pdump, check all the packets length are 960 Byte and the payload in receive packets are same in each pcap file.
+
+14. Quit and relaunch vhost and rerun step 11-13.
+
+15. Quit and relaunch virtio with split ring inorder non-mergeable path as below::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 30,31 -n 4 --file-prefix=virtio-user0 --no-pci \
+	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=./vhost-net0,queues=8,mrg_rxbuf=0,in_order=1,server=1 \
+	-- -i --nb-cores=1 --rxq=8 --txq=8 --txd=1024 --rxd=1024
+	testpmd>set fwd csum
+	testpmd>start
+
+16. Rerun step 11-14.
+
+17. Quit and relaunch virtio with split ring vectorized path as below::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 30,31 -n 4 --file-prefix=virtio-user0 --no-pci \
+	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=./vhost-net0,queues=8,mrg_rxbuf=0,in_order=0,vectorized=1,server=1 \
+	-- -i --nb-cores=1 --rxq=8 --txq=8 --txd=1024 --rxd=1024
+	testpmd>set fwd csum
+	testpmd>start
+
+18. Rerun step 11-14.
+
+19. Quit and relaunch vhost w/ iova=pa::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 10-18 -n 4 -a 0000:00:04.0 -a 0000:00:04.1 -a 0000:00:04.2 \
+	--vdev 'eth_vhost0,iface=vhost-net0,queues=8,client=1,dmas=[txq0;txq1;txq2;txq3;txq4;txq5;txq6]' \
+	--iova=pa -- -i --nb-cores=5 --rxq=8 --txq=8 --txd=1024 --rxd=1024 \
+	--lcore-dma=[lcore11@0000:00:04.0,lcore12@0000:00:04.0,lcore13@0000:00:04.1,lcore13@0000:00:04.2,lcore14@0000:00:04.1,lcore14@0000:00:04.2,lcore15@0000:00:04.1,lcore15@0000:00:04.2]
+
+20. Rerun steps 3-6.
+
+Test Case 3: loopback split ring large chain packets stress test with server mode and cbdma enqueue
+---------------------------------------------------------------------------------------------------
+This is a stress test case about forwading large chain packets in loopback vhost-user/virtio-user split ring with server mode 
+when vhost uses the asynchronous enqueue operations with CBDMA channels. Both iova as VA and PA mode test.
+
+1. Bind 1 CBDMA channel to vfio-pci, as common step 1.
+
+2. Launch vhost by below command::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 2-3 -n 4 -a 0000:00:04.0 \
+	--vdev 'eth_vhost0,iface=vhost-net0,queues=1,client=1,dmas=[txq0]' --iova=va -- -i --nb-cores=1 --mbuf-size=65535 --lcore-dma=[lcore3@0000:00:04.0]
+
+3. Launch virtio and start testpmd::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 30,31 -n 4  --file-prefix=testpmd0 --no-pci  \
+	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=./vhost-net0,queues=1,server=1,mrg_rxbuf=1,in_order=0,vectorized=1,queue_size=2048 \
+	-- -i --rxq=1 --txq=1 --txd=2048 --rxd=2048 --nb-cores=1
+	testpmd>start
+
+4. Send large packets from vhost, check virtio can receive packets::
+
+	testpmd> set txpkts 65535,65535,65535,65535,65535
+	testpmd> start tx_first 32
+	testpmd> show port stats all
+
+5. Stop and quit vhost testpmd and relaunch vhost with iova=pa::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 2-3 -n 4 -a 0000:00:04.0 \
+	--vdev 'eth_vhost0,iface=vhost-net0,queues=1,client=1,dmas=[txq0]' --iova=pa -- -i --nb-cores=1 --mbuf-size=65535 --lcore-dma=[lcore3@0000:00:04.0]
+
+6. Rerun steps 4.
+
+Test Case 4: loopback packed ring large chain packets stress test with server mode and cbdma enqueue
+----------------------------------------------------------------------------------------------------
+This is a stress test case about forwading large chain packets in loopback vhost-user/virtio-user packed ring with server mode 
+when vhost uses the asynchronous enqueue operations with dsa dpdk driver. Both iova as VA and PA mode test.
+
+1. Bind 1 CBDMA channel to vfio-pci, as common step 1.
+
+2. Launch vhost by below command::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 2-3 -n 4 -a 0000:00:04.0 \
+	--vdev 'eth_vhost0,iface=vhost-net0,queues=1,dmas=[txq0],client=1' --iova=va -- -i --nb-cores=1 --mbuf-size=65535 --lcore-dma=[lcore3@0000:00:04.0]
+
+3. Launch virtio and start testpmd::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 30,31 -n 4  --file-prefix=testpmd0 --no-pci  \
+	--vdev=net_virtio_user0,mac=00:11:22:33:44:10,path=./vhost-net0,queues=1,mrg_rxbuf=1,in_order=0,vectorized=1,packed_vq=1,queue_size=2048,server=1 \
+	-- -i --rxq=1 --txq=1 --txd=2048 --rxd=2048 --nb-cores=1
+	testpmd>start
+
+4. Send large packets from vhost, check virtio can receive packets::
+
+	testpmd> set txpkts 65535,65535,65535,65535,65535
+	testpmd> start tx_first 32
+	testpmd> show port stats all
+
+5. Stop and quit vhost testpmd and relaunch vhost with iova=pa::
+
+	<dpdk dir># ./x86_64-native-linuxapp-gcc/app/dpdk-testpmd -l 2-3 -n 4 -a 0000:00:04.0 \
+	--vdev 'eth_vhost0,iface=vhost-net0,queues=1,dmas=[txq0],client=1' --iova=pa -- -i --nb-cores=1 --mbuf-size=65535 --lcore-dma=[lcore3@0000:00:04.0]
+
+6. Rerun steps 4.
-- 
2.34.1