Virtio-serial API
From KVM
Guest API
| Function | Linux guest | Windows guest |
|---|---|---|
| Port discovery | symlinks from /dev/virtio-port/<portname> to /dev/vportNpn | |
| Opening port | open(2). Returns >= 0 on success. Only one open allowed at a time for a port. | |
| Reading | read(2). Blocking as well as non-blocking reads available. Return 0 if host is not connected. Block or -EINTR otherwise. Return -ENODEV if port or device get hot-unplugged | |
| Writing | write(2). Blocking as well as non-blocking. If host is not connected, write blocks or returns -EINTR. Return -ENODEV if port or device get hot-unplugged. | |
| Poll | poll(). POLLIN, POLLOUT with usual meaning. POLLHUP when host is not connected or when port or device got unplugged | |
| Signals | From kernel 2.6.37, SIGIO will be sent to guest apps that set O_ASYNC flag on the fd. SIGIO will be sent on host connection up, down and port unplug events. |