| .. _vhost_user_input: |
| |
| QEMU vhost-user-input - Input emulation |
| ======================================= |
| |
| This document describes the setup and usage of the Virtio input device. |
| The Virtio input device is a paravirtualized device for input events. |
| |
| Description |
| ----------- |
| |
| The vhost-user-input device implementation was designed to work with a daemon |
| polling on input devices and passes input events to the guest. |
| |
| QEMU provides a backend implementation in contrib/vhost-user-input. |
| |
| Linux kernel support |
| -------------------- |
| |
| Virtio input requires a guest Linux kernel built with the |
| ``CONFIG_VIRTIO_INPUT`` option. |
| |
| Examples |
| -------- |
| |
| The backend daemon should be started first: |
| |
| :: |
| |
| host# vhost-user-input --socket-path=input.sock \ |
| --evdev-path=/dev/input/event17 |
| |
| The QEMU invocation needs to create a chardev socket to communicate with the |
| backend daemon and access the VirtIO queues with the guest over the |
| :ref:`shared memory <shared_memory_object>`. |
| |
| :: |
| |
| host# qemu-system \ |
| -chardev socket,path=/tmp/input.sock,id=mouse0 \ |
| -device vhost-user-input-pci,chardev=mouse0 \ |
| -m 4096 \ |
| -object memory-backend-file,id=mem,size=4G,mem-path=/dev/shm,share=on \ |
| -numa node,memdev=mem \ |
| ... |
