On Fri, Oct 10, 2025 at 09:00:21PM +0800, Robert Hoo wrote:
Hi,
Does vsock support communication between guests?
From man page, and my experiment, seems it doesn't.
But why not?
It depends, vhost-user vsock device, supports it.
See
https://github.com/rust-vmm/vhost-device/tree/main/vhost-device-vsock#sibling-vm-communication
The vhost-vsock in-kernel device doesn't support it.
The main problem is that vsock is designed for host<->guest
communication, so implementing a guest<->guest communication is
possible, but requires more configuration (e.g. some kind of firewall,
etc.) and also an extension to the address (see the required
`.svm_flags = VMADDR_FLAG_TO_HOST` in the link).
The easy way to do that with vhost-vsock, is to use socat in the host to
concatenate 2 VMs (some examples here:
https://stefano-garzarella.github.io/posts/2021-01-22-socat-vsock/)
Cheers,
Stefano
