1 /* 2 * Virtio RNG Support 3 * 4 * Copyright Red Hat, Inc. 2012 5 * Copyright Amit Shah <amit.shah@redhat.com> 6 * 7 * This work is licensed under the terms of the GNU GPL, version 2 or 8 * (at your option) any later version. See the COPYING file in the 9 * top-level directory. 10 */ 11 12 #ifndef _QEMU_VIRTIO_RNG_H 13 #define _QEMU_VIRTIO_RNG_H 14 15 #include "sysemu/rng.h" 16 #include "sysemu/rng-random.h" 17 #include "standard-headers/linux/virtio_rng.h" 18 19 #define TYPE_VIRTIO_RNG "virtio-rng-device" 20 #define VIRTIO_RNG(obj) \ 21 OBJECT_CHECK(VirtIORNG, (obj), TYPE_VIRTIO_RNG) 22 #define VIRTIO_RNG_GET_PARENT_CLASS(obj) \ 23 OBJECT_GET_PARENT_CLASS(obj, TYPE_VIRTIO_RNG) 24 25 struct VirtIORNGConf { 26 RngBackend *rng; 27 uint64_t max_bytes; 28 uint32_t period_ms; 29 RndRandom *default_backend; 30 }; 31 32 typedef struct VirtIORNG { 33 VirtIODevice parent_obj; 34 35 /* Only one vq - guest puts buffer(s) on it when it needs entropy */ 36 VirtQueue *vq; 37 38 VirtIORNGConf conf; 39 40 RngBackend *rng; 41 42 /* We purposefully don't migrate this state. The quota will reset on the 43 * destination as a result. Rate limiting is host state, not guest state. 44 */ 45 QEMUTimer *rate_limit_timer; 46 int64_t quota_remaining; 47 } VirtIORNG; 48 49 /* Set a default rate limit of 2^47 bytes per minute or roughly 2TB/s. If 50 you have an entropy source capable of generating more entropy than this 51 and you can pass it through via virtio-rng, then hats off to you. Until 52 then, this is unlimited for all practical purposes. 53 */ 54 #define DEFINE_VIRTIO_RNG_PROPERTIES(_state, _conf_field) \ 55 DEFINE_PROP_UINT64("max-bytes", _state, _conf_field.max_bytes, \ 56 INT64_MAX), \ 57 DEFINE_PROP_UINT32("period", _state, _conf_field.period_ms, 1 << 16) 58 59 #endif 60