| /* |
| * A virtio device implementing a hardware random number generator. |
| * |
| * Copyright 2012 Red Hat, Inc. |
| * Copyright 2012 Amit Shah <amit.shah@redhat.com> |
| * |
| * This work is licensed under the terms of the GNU GPL, version 2 or |
| * (at your option) any later version. See the COPYING file in the |
| * top-level directory. |
| */ |
| |
| #include "qemu/iov.h" |
| #include "hw/qdev.h" |
| #include "qapi/qmp/qerror.h" |
| #include "hw/virtio/virtio.h" |
| #include "hw/virtio/virtio-rng.h" |
| #include "sysemu/rng.h" |
| #include "qom/object_interfaces.h" |
| #include "trace.h" |
| |
| static bool is_guest_ready(VirtIORNG *vrng) |
| { |
| VirtIODevice *vdev = VIRTIO_DEVICE(vrng); |
| if (virtio_queue_ready(vrng->vq) |
| && (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) { |
| return true; |
| } |
| trace_virtio_rng_guest_not_ready(vrng); |
| return false; |
| } |
| |
| static size_t get_request_size(VirtQueue *vq, unsigned quota) |
| { |
| unsigned int in, out; |
| |
| virtqueue_get_avail_bytes(vq, &in, &out, quota, 0); |
| return in; |
| } |
| |
| static void virtio_rng_process(VirtIORNG *vrng); |
| |
| /* Send data from a char device over to the guest */ |
| static void chr_read(void *opaque, const void *buf, size_t size) |
| { |
| VirtIORNG *vrng = opaque; |
| VirtIODevice *vdev = VIRTIO_DEVICE(vrng); |
| VirtQueueElement elem; |
| size_t len; |
| int offset; |
| |
| if (!is_guest_ready(vrng)) { |
| return; |
| } |
| |
| vrng->quota_remaining -= size; |
| |
| offset = 0; |
| while (offset < size) { |
| if (!virtqueue_pop(vrng->vq, &elem)) { |
| break; |
| } |
| len = iov_from_buf(elem.in_sg, elem.in_num, |
| 0, buf + offset, size - offset); |
| offset += len; |
| |
| virtqueue_push(vrng->vq, &elem, len); |
| trace_virtio_rng_pushed(vrng, len); |
| } |
| virtio_notify(vdev, vrng->vq); |
| } |
| |
| static void virtio_rng_process(VirtIORNG *vrng) |
| { |
| size_t size; |
| unsigned quota; |
| |
| if (!is_guest_ready(vrng)) { |
| return; |
| } |
| |
| if (vrng->quota_remaining < 0) { |
| quota = 0; |
| } else { |
| quota = MIN((uint64_t)vrng->quota_remaining, (uint64_t)UINT32_MAX); |
| } |
| size = get_request_size(vrng->vq, quota); |
| |
| trace_virtio_rng_request(vrng, size, quota); |
| |
| size = MIN(vrng->quota_remaining, size); |
| if (size) { |
| rng_backend_request_entropy(vrng->rng, size, chr_read, vrng); |
| } |
| } |
| |
| static void handle_input(VirtIODevice *vdev, VirtQueue *vq) |
| { |
| VirtIORNG *vrng = VIRTIO_RNG(vdev); |
| virtio_rng_process(vrng); |
| } |
| |
| static uint32_t get_features(VirtIODevice *vdev, uint32_t f) |
| { |
| return f; |
| } |
| |
| static void virtio_rng_save(QEMUFile *f, void *opaque) |
| { |
| VirtIODevice *vdev = opaque; |
| |
| virtio_save(vdev, f); |
| } |
| |
| static int virtio_rng_load(QEMUFile *f, void *opaque, int version_id) |
| { |
| VirtIORNG *vrng = opaque; |
| int ret; |
| |
| if (version_id != 1) { |
| return -EINVAL; |
| } |
| ret = virtio_load(VIRTIO_DEVICE(vrng), f, version_id); |
| if (ret != 0) { |
| return ret; |
| } |
| |
| /* We may have an element ready but couldn't process it due to a quota |
| * limit. Make sure to try again after live migration when the quota may |
| * have been reset. |
| */ |
| virtio_rng_process(vrng); |
| |
| return 0; |
| } |
| |
| static void check_rate_limit(void *opaque) |
| { |
| VirtIORNG *vrng = opaque; |
| |
| vrng->quota_remaining = vrng->conf.max_bytes; |
| virtio_rng_process(vrng); |
| timer_mod(vrng->rate_limit_timer, |
| qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + vrng->conf.period_ms); |
| } |
| |
| static void virtio_rng_device_realize(DeviceState *dev, Error **errp) |
| { |
| VirtIODevice *vdev = VIRTIO_DEVICE(dev); |
| VirtIORNG *vrng = VIRTIO_RNG(dev); |
| Error *local_err = NULL; |
| |
| if (!vrng->conf.period_ms > 0) { |
| error_setg(errp, "'period' parameter expects a positive integer"); |
| return; |
| } |
| |
| /* Workaround: Property parsing does not enforce unsigned integers, |
| * So this is a hack to reject such numbers. */ |
| if (vrng->conf.max_bytes > INT64_MAX) { |
| error_setg(errp, "'max-bytes' parameter must be non-negative, " |
| "and less than 2^63"); |
| return; |
| } |
| |
| if (vrng->conf.rng == NULL) { |
| vrng->conf.default_backend = RNG_RANDOM(object_new(TYPE_RNG_RANDOM)); |
| |
| user_creatable_complete(OBJECT(vrng->conf.default_backend), |
| &local_err); |
| if (local_err) { |
| error_propagate(errp, local_err); |
| object_unref(OBJECT(vrng->conf.default_backend)); |
| return; |
| } |
| |
| object_property_add_child(OBJECT(dev), |
| "default-backend", |
| OBJECT(vrng->conf.default_backend), |
| NULL); |
| |
| /* The child property took a reference, we can safely drop ours now */ |
| object_unref(OBJECT(vrng->conf.default_backend)); |
| |
| object_property_set_link(OBJECT(dev), |
| OBJECT(vrng->conf.default_backend), |
| "rng", NULL); |
| } |
| |
| vrng->rng = vrng->conf.rng; |
| if (vrng->rng == NULL) { |
| error_setg(errp, "'rng' parameter expects a valid object"); |
| return; |
| } |
| |
| virtio_init(vdev, "virtio-rng", VIRTIO_ID_RNG, 0); |
| |
| vrng->vq = virtio_add_queue(vdev, 8, handle_input); |
| vrng->quota_remaining = vrng->conf.max_bytes; |
| |
| vrng->rate_limit_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, |
| check_rate_limit, vrng); |
| |
| timer_mod(vrng->rate_limit_timer, |
| qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + vrng->conf.period_ms); |
| |
| register_savevm(dev, "virtio-rng", -1, 1, virtio_rng_save, |
| virtio_rng_load, vrng); |
| } |
| |
| static void virtio_rng_device_unrealize(DeviceState *dev, Error **errp) |
| { |
| VirtIODevice *vdev = VIRTIO_DEVICE(dev); |
| VirtIORNG *vrng = VIRTIO_RNG(dev); |
| |
| timer_del(vrng->rate_limit_timer); |
| timer_free(vrng->rate_limit_timer); |
| unregister_savevm(dev, "virtio-rng", vrng); |
| virtio_cleanup(vdev); |
| } |
| |
| static Property virtio_rng_properties[] = { |
| DEFINE_VIRTIO_RNG_PROPERTIES(VirtIORNG, conf), |
| DEFINE_PROP_END_OF_LIST(), |
| }; |
| |
| static void virtio_rng_class_init(ObjectClass *klass, void *data) |
| { |
| DeviceClass *dc = DEVICE_CLASS(klass); |
| VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); |
| |
| dc->props = virtio_rng_properties; |
| set_bit(DEVICE_CATEGORY_MISC, dc->categories); |
| vdc->realize = virtio_rng_device_realize; |
| vdc->unrealize = virtio_rng_device_unrealize; |
| vdc->get_features = get_features; |
| } |
| |
| static void virtio_rng_initfn(Object *obj) |
| { |
| VirtIORNG *vrng = VIRTIO_RNG(obj); |
| |
| object_property_add_link(obj, "rng", TYPE_RNG_BACKEND, |
| (Object **)&vrng->conf.rng, |
| qdev_prop_allow_set_link_before_realize, |
| OBJ_PROP_LINK_UNREF_ON_RELEASE, NULL); |
| } |
| |
| static const TypeInfo virtio_rng_info = { |
| .name = TYPE_VIRTIO_RNG, |
| .parent = TYPE_VIRTIO_DEVICE, |
| .instance_size = sizeof(VirtIORNG), |
| .instance_init = virtio_rng_initfn, |
| .class_init = virtio_rng_class_init, |
| }; |
| |
| static void virtio_register_types(void) |
| { |
| type_register_static(&virtio_rng_info); |
| } |
| |
| type_init(virtio_register_types) |