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externalof

Member

Registered: 2025-06-03

Posts: 1

Tap (with host <-> vm pings) real ip, over wifi

Hello,
I am utilizing QEMU to run two Windows virtual machines (VMs) for driver development purposes. For simplicity, let's focus on a single host and a single VM configuration.

my qemu setup (no libvirt, virt-manger)
```
qemu-system-x86_64 -enable-kvm -cpu host -m 2G -smp 6,cores=1,threads=1 \
-drive file=win10.img,format=raw,if=none,id=hd \
-device ahci,id=ahci \
-device ide-hd,drive=hd,bus=ahci.0 \
-display sdl
```

The host machine (a laptop) is connected to the internet via Wi-Fi.
Both the host and the VM should have real IP addresses within the same subnet, as assigned by the Wi-Fi router.
Only the host and the VM should appear in the router's logs. (meaning no 3-rd phantom device etc)

In Windows, creating a network bridge over Wi-Fi is straightforward using the Network Manager. Similarly, OpenWRT simplifies this process. However, I am seeking a method to achieve the same bridged networking setup on a Linux host, specifically with QEMU, while connected to Wi-Fi.

Wifi adapter after all configuration on host should still be able to work as Access Point if needed

Last edited by externalof (2025-06-03 12:01:42)

-thc

Member

Registered: 2017-03-15

Posts: 934

Re: Tap (with host <-> vm pings) real ip, over wifi

AFAIK the "upstream" connection from a qemu VM to the host is accomplished by something like this:

qemu-system-x86_64 [...] -netdev type=tap,id=net0,ifname=tap0,script=no,downscript=no,vhost=on [...]

It's up to you to create the tap device ("tap0") and the bridge with your chosen network management (I have done this via systemd-networkd).

Wifi adapter after all configuration on host should still be able to work as Access Point if needed

Does this already work with your WiFi card (simultaneous client/AP)?

Last edited by -thc (2025-06-03 13:41:57)