I came across this blog post[0] concerning passt, which is an alternative usermode networking implementation for QEMU.

I'm working on a project that uses QEMU on Windows hosts running Linux guests. I'm trying to get faster usermode networking than is available with libslirp. My performance target is 200Mbps even on older or less powerful hardware, such as Celeron mini PCs. Currently I'm seeing 15-30MBps with libslirp.

It appears that passt doesn't currently support Windows, correct? Is there a guess as to how difficult that might be to implement? If the speedup is significant, I would be interested in taking a crack at adding Windows support.

Thanks,
//anders

[0]: http://blog.vmsplice.net/2021/10/a-new-approach-to-usermode-networking.html