Add description and example for the vhost-user based RNG implementation. Tailored on Viresh Kumar's vhost-user-i2c documentation.
Signed-off-by: Mathieu Poirier mathieu.poirier@linaro.org --- docs/tools/vhost-user-rng.rst | 74 +++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) create mode 100644 docs/tools/vhost-user-rng.rst
diff --git a/docs/tools/vhost-user-rng.rst b/docs/tools/vhost-user-rng.rst new file mode 100644 index 000000000000..7f69d7bb3c58 --- /dev/null +++ b/docs/tools/vhost-user-rng.rst @@ -0,0 +1,74 @@ +QEMU vhost-user-rng - RNG emulation backend +=========================================== + +Synopsis +-------- + +**vhost-user-rng** [*OPTIONS*] + +Description +----------- + +This program is a vhost-user backend that emulates a VirtIO random number +generator (RNG). It uses the host's random number generator pool, +/dev/urandom by default but configurable at will, to satisfy requests from +guests. + +This program is designed to work with QEMU's ``-device +vhost-user-rng-pci`` but should work with any virtual machine monitor +(VMM) that supports vhost-user. See the Examples section below. + +Options +------- + +.. program:: vhost-user-rng + +.. option:: -h, --help + + Print help. + +.. option:: -v, --verbose + + Increase verbosity of output + +.. option:: -s, --socket-path=PATH + + Listen on vhost-user UNIX domain socket at PATH. Incompatible with --fd. + +.. option:: -f, --fd=FDNUM + + Accept connections from vhost-user UNIX domain socket file descriptor FDNUM. + The file descriptor must already be listening for connections. + Incompatible with --socket-path. + +.. option:: -p, --period + + Rate, in milliseconds, at which the RNG hardware can generate random data. + Used in conjunction with the --max-bytes option. + +.. option:: -m, --max-bytes + + In conjuction with the --period parameter, provides the maximum number of byte + per milliseconds a RNG device can generate. + +Examples +-------- + +The daemon should be started first: + +:: + + host# vhost-user-rng --socket-path=rng.sock --period=1000 --max-bytes=4096 + +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 \ + ...