Re: [PATCH v4 3/3] docs: Add documentation for vhost based RNG implementation

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Sep 27, 2021 at 04:13:59PM -0600, Mathieu Poirier wrote:
> Add description and example for the vhost-user based RNG implementation.
> 
> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

Causes a build failure:

Warning, treated as error:
/scm/qemu/docs/system/devices/vhost-user-rng.rst:document isn't included in any toctree



> ---
>  docs/system/devices/vhost-user-rng.rst | 39 ++++++++++++++++++++++++++
>  1 file changed, 39 insertions(+)
>  create mode 100644 docs/system/devices/vhost-user-rng.rst
> 
> diff --git a/docs/system/devices/vhost-user-rng.rst b/docs/system/devices/vhost-user-rng.rst
> new file mode 100644
> index 000000000000..a145d4105c1a
> --- /dev/null
> +++ b/docs/system/devices/vhost-user-rng.rst
> @@ -0,0 +1,39 @@
> +QEMU vhost-user-rng - RNG emulation
> +===================================
> +
> +Background
> +----------
> +
> +What follows builds on the material presented in vhost-user.rst - it should
> +be reviewed before moving forward with the content in this file.
> +
> +Description
> +-----------
> +
> +The vhost-user-rng device implementation was designed to work with a random
> +number generator daemon such as the one found in the vhost-device crate of
> +the rust-vmm project available on github [1].
> +
> +[1]. https://github.com/rust-vmm/vhost-device
> +
> +Examples
> +--------
> +
> +The daemon should be started first:
> +
> +::
> +
> +  host# vhost-device-rng --socket-path=rng.sock -c 1 -m 512 -p 1000
> +
> +The QEMU invocation needs to create a chardev socket the device can
> +use to communicate as well as share the guests memory over a memfd.
> +
> +::
> +
> +  host# qemu-system								\
> +      -chardev socket,path=$(PATH)/rng.sock,id=rng0				\
> +      -device vhost-user-rng-pci,chardev=rng0					\
> +      -m 4096 									\
> +      -object memory-backend-file,id=mem,size=4G,mem-path=/dev/shm,share=on	\
> +      -numa node,memdev=mem							\
> +      ...
> -- 
> 2.25.1