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 18 #define TYPE_VIRTIO_RNG "virtio-rng-device" 19 #define VIRTIO_RNG(obj) \ 20 OBJECT_CHECK(VirtIORNG, (obj), TYPE_VIRTIO_RNG) 21 #define VIRTIO_RNG_GET_PARENT_CLASS(obj) \ 22 OBJECT_GET_PARENT_CLASS(obj, TYPE_VIRTIO_RNG) 23 24 /* The Virtio ID for the virtio rng device */ 25 #define VIRTIO_ID_RNG 4 26 27 struct VirtIORNGConf { 28 RngBackend *rng; 29 uint64_t max_bytes; 30 uint32_t period_ms; 31 RndRandom *default_backend; 32 }; 33 34 typedef struct VirtIORNG { 35 VirtIODevice parent_obj; 36 37 /* Only one vq - guest puts buffer(s) on it when it needs entropy */ 38 VirtQueue *vq; 39 40 VirtIORNGConf conf; 41 42 RngBackend *rng; 43 44 /* We purposefully don't migrate this state. The quota will reset on the 45 * destination as a result. Rate limiting is host state, not guest state. 46 */ 47 QEMUTimer *rate_limit_timer; 48 int64_t quota_remaining; 49 } VirtIORNG; 50 51 /* Set a default rate limit of 2^47 bytes per minute or roughly 2TB/s. If 52 you have an entropy source capable of generating more entropy than this 53 and you can pass it through via virtio-rng, then hats off to you. Until 54 then, this is unlimited for all practical purposes. 55 */ 56 #define DEFINE_VIRTIO_RNG_PROPERTIES(_state, _conf_field) \ 57 DEFINE_PROP_UINT64("max-bytes", _state, _conf_field.max_bytes, \ 58 INT64_MAX), \ 59 DEFINE_PROP_UINT32("period", _state, _conf_field.period_ms, 1 << 16) 60 61 #endif 62