Please, add important note to https://wiki.qemu.org/Features/VirtioVsock page, that this feature only supported in KVM accelerated mode. It's not obvious. Furthermore, it isn't checked by qemu when invoking with "-device vhost-vsock-pci,..." and user encounters this only when communicating (via AF_VSOCK) application fails to connect() with weird "Connection timed out" error. --
С уважением, Артем Писаренко
