On 11/6/2025 10:32 PM, Stefano Garzarella wrote:
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
Nice, thanks Stefano. It sounds ideal for my VM <--> VM communication
requirement. I'll read the doc carefully later.
BTW, I also found your vsock-bridge
(https://github.com/stefano-garzarella/vsock-bridge); but seems its last commit
was 5 yrs ago. It's not recommended, is it?
