使用DPDK配置移动边缘计算NES环境时Qemu缺失usvhost-1设备报错

Hey there, let's break down what's going wrong here and get your NES environment up and running smoothly.

The Core Issue #

The error Qemu-System-X86_64: -Chardev Socket,Id=Char1,Path=/Usr/Bin/Usvhost-1: Failed To Connect Socket: No Such File Or Directory boils down to two key problems:

• You’re pointing QEMU to look for a vhost-user socket at /usr/bin/usvhost-1 — this path is totally incorrect. /usr/bin is meant for executable binaries, not the socket files that DPDK/NES generates.
• The socket file usvhost-1 simply doesn’t exist at that location (and shouldn’t be there in the first place).

Step-by-Step Fixes #

1. Correct the Vhost-User Socket Path in NES Configuration

First, open your NES config file (the one referenced by NES_SERVER_CONF=/opt/intel/nev_sdk/nes_root/scripts/nes.cfg):

vi /opt/intel/nev_sdk/nes_root/scripts/nes.cfg

Look for settings related to vhost-user sockets (usually labeled something like vhost_socket_path). Update the path to a valid, writable directory — common choices include:

• /tmp/usvhost-1 (temporary directory, easy to access and manage)
• /mnt/huge-1048576kB/usvhost-1 (same directory as your hugepages, keeps related files grouped)

Save the config file after making this change.

2. Verify the Socket is Created by nes-daemon

Restart the nes-daemon to apply the new config:

cd /opt/intel/nev_sdk/nes_root/scripts/
./nes-daemon-stop # Run this if the daemon is already active
./nes-daemon-start

After starting, confirm the socket file exists at your new path with:

ls -l /tmp/usvhost-1 # Replace with your chosen path

You should see a socket file listed (it will have an s in the permissions column, indicating it’s a socket type).

3. Fix the QEMU Command

Update your QEMU command to use the corrected socket path. Here’s the adjusted version of your command:

/usr/local/bin/qemu-system-x86_64 -enable-kvm -cpu host -m 4096 -no-reboot -no-hpet \
-drive file=/home/tcs/ubuntu-14.04.5-desktop-amd64.iso,if=virtio,id=drive-virtio-disk1,format=raw \
-object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge-1048576kB/,share=on \
-numa node,memdev=mem -mem-prealloc \
-device virtio-net-pci,netdev=net0,mac=ac:1f:6b:09:cb:9a -netdev type=tap,id=net0 \
-chardev socket,id=char1,path=/tmp/usvhost-1 \ # This line is fixed!
-netdev type=vhost-user,id=mynet1,chardev=char1 \
-device virtio-net-pci,mac=52:54:00:00:00:01,netdev=mynet1,id=net1,csum=off,gso=off,guest_csum=off,guest_tso4=off,guest_tso6=off,guest_ecn=off

4. Additional Checks to Avoid Future Issues

• Load the vhost kernel module: DPDK’s vhost-user functionality requires the vhost_net module. Load it with:

  modprobe vhost_net
  

• Match permissions: Ensure the user running QEMU has read/write access to the socket file. If nes-daemon runs as root, run QEMU as root too, or adjust socket permissions with chmod 666 /tmp/usvhost-1.
• Validate DPDK environment: Double-check that your RTE_SDK and RTE_TARGET variables are set correctly, and that nes-daemon was compiled against the same DPDK version you’re using.

内容的提问来源于stack exchange，提问作者sanjay