projects / mirror_qemu.git / blame
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|---|---|---|
| 887d5775 LY |
1 | .. _vhost_user_input: |
| 2 | ||
| 3 | QEMU vhost-user-input - Input emulation | |
| 4 | ======================================= | |
| 5 | ||
| 6 | This document describes the setup and usage of the Virtio input device. | |
| 7 | The Virtio input device is a paravirtualized device for input events. | |
| 8 | ||
| 9 | Description | |
| 10 | ----------- | |
| 11 | ||
| 12 | The vhost-user-input device implementation was designed to work with a daemon | |
| 13 | polling on input devices and passes input events to the guest. | |
| 14 | ||
| 15 | QEMU provides a backend implementation in contrib/vhost-user-input. | |
| 16 | ||
| 17 | Linux kernel support | |
| 18 | -------------------- | |
| 19 | ||
| 20 | Virtio input requires a guest Linux kernel built with the | |
| 21 | ``CONFIG_VIRTIO_INPUT`` option. | |
| 22 | ||
| 23 | Examples | |
| 24 | -------- | |
| 25 | ||
| 26 | The backend daemon should be started first: | |
| 27 | ||
| 28 | :: | |
| 29 | ||
| 30 | host# vhost-user-input --socket-path=input.sock \ | |
| 31 | --evdev-path=/dev/input/event17 | |
| 32 | ||
| 33 | The QEMU invocation needs to create a chardev socket to communicate with the | |
| 34 | backend daemon and access the VirtIO queues with the guest over the | |
| 35 | :ref:`shared memory <shared_memory_object>`. | |
| 36 | ||
| 37 | :: | |
| 38 | ||
| 39 | host# qemu-system \ | |
| 40 | -chardev socket,path=/tmp/input.sock,id=mouse0 \ | |
| 41 | -device vhost-user-input-pci,chardev=mouse0 \ | |
| 42 | -m 4096 \ | |
| 43 | -object memory-backend-file,id=mem,size=4G,mem-path=/dev/shm,share=on \ | |
| 44 | -numa node,memdev=mem \ | |
| 45 | ... |