Network access from a VM

[ghost]

My goal is to provide network access from a VM.

I created tap0 device on host machine:
sudo ip tuntap add dev tap0 mode tap
sudo ip link set dev tap0 up
sudo ip addr add 192.168.1.1/24 dev tap0

Created VM:

./cloud-hypervisor \
	--kernel ./hypervisor-fw \
	--disk path=focal-server-cloudimg-amd64.raw path=/tmp/ubuntu-cloudinit.img \
	--cpus boot=4 \
	--memory size=1024M \
	--net "tap=tap0,mac=00:11:22:33:44:55,ip=192.168.1.100,mask=255.255.255.0"

ip addr inside the VM:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:11:22:33:44:55 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::211:22ff:fe33:4455/64 scope link 
       valid_lft forever preferred_lft forever

No internet access.

What mistake I made?
Not sure how networking works here, any advice is appreciated.

[ghost]

Also tried from: https://github.com/cloud-hypervisor/cloud-hypervisor/blob/main/docs/macvtap-bridge.md

sudo ./cloud-hypervisor \
	--kernel ./hypervisor-fw \
	--disk path=focal-server-cloudimg-amd64.raw path=/tmp/ubuntu-cloudinit.img \
	--cpus boot=4 \
	--memory size=2048M \
	--net fd=3,mac=$mac 3<>$"$tapdevice" \

Getting error:

Error booting VM: VmBoot(DeviceManager(CreateVirtioNet(TapError(IoctlError(2147767506, Os { code: 25, kind: Uncategorized, message: "Not a tty" })))))

[likebreath]

Your guest network interface (ens4) does not have a IP. You may need to manually assign one to it. Also, you will need to make sure your host has the right routing and iptable rules (e.g. allowing forwarding packages).

Are you using a regular terminal to run the Cloud Hypervisor command with macvtap? Also, you can run the two macvtap integration tests locally to see if macvtap works in your environment. It only requires docker to be installed. You can run them with a single command:

$ ./scripts/dev_cli.sh tests --integration -- --test-filter test_macvtap

[adamliyi]

@kochia5 , please refer to: #4917 (comment)
In this case, if starting cloud hypervisor as 'sudo', there might be ioctl error. Try login in as root, and removing sudo.

[peng6662001]

@kochia5 Pleae reference Virtual-machine-network-configuration