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Diffstat (limited to 'docs/system/devices/vhost-user-input.rst')
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diff --git a/docs/system/devices/vhost-user-input.rst b/docs/system/devices/vhost-user-input.rst new file mode 100644 index 0000000000..118eb78101 --- /dev/null +++ b/docs/system/devices/vhost-user-input.rst @@ -0,0 +1,45 @@ +.. _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 \ + ... |