mirror of https://github.com/proxmox/mirror_qemu
212 lines
5.1 KiB
C
212 lines
5.1 KiB
C
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/*
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* A virtio device implementing a hardware random number generator.
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*
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* Copyright 2012 Red Hat, Inc.
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* Copyright 2012 Amit Shah <amit.shah@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or
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* (at your option) any later version. See the COPYING file in the
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* top-level directory.
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*/
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#include "iov.h"
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#include "qdev.h"
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#include "virtio.h"
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#include "virtio-rng.h"
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#include "qemu/rng.h"
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typedef struct VirtIORNG {
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VirtIODevice vdev;
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DeviceState *qdev;
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/* Only one vq - guest puts buffer(s) on it when it needs entropy */
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VirtQueue *vq;
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VirtQueueElement elem;
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/* Config data for the device -- currently only chardev */
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VirtIORNGConf *conf;
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/* Whether we've popped a vq element into 'elem' above */
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bool popped;
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RngBackend *rng;
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} VirtIORNG;
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static bool is_guest_ready(VirtIORNG *vrng)
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{
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if (virtio_queue_ready(vrng->vq)
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&& (vrng->vdev.status & VIRTIO_CONFIG_S_DRIVER_OK)) {
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return true;
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}
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return false;
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}
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static size_t pop_an_elem(VirtIORNG *vrng)
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{
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size_t size;
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if (!vrng->popped && !virtqueue_pop(vrng->vq, &vrng->elem)) {
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return 0;
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}
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vrng->popped = true;
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size = iov_size(vrng->elem.in_sg, vrng->elem.in_num);
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return size;
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}
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/* Send data from a char device over to the guest */
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static void chr_read(void *opaque, const void *buf, size_t size)
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{
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VirtIORNG *vrng = opaque;
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size_t len;
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int offset;
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if (!is_guest_ready(vrng)) {
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return;
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}
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offset = 0;
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while (offset < size) {
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if (!pop_an_elem(vrng)) {
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break;
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}
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len = iov_from_buf(vrng->elem.in_sg, vrng->elem.in_num,
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0, buf + offset, size - offset);
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offset += len;
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virtqueue_push(vrng->vq, &vrng->elem, len);
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vrng->popped = false;
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}
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virtio_notify(&vrng->vdev, vrng->vq);
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/*
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* Lastly, if we had multiple elems queued by the guest, and we
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* didn't have enough data to fill them all, indicate we want more
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* data.
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*/
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len = pop_an_elem(vrng);
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if (len) {
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rng_backend_request_entropy(vrng->rng, size, chr_read, vrng);
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}
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}
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static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
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{
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VirtIORNG *vrng = DO_UPCAST(VirtIORNG, vdev, vdev);
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size_t size;
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size = pop_an_elem(vrng);
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if (size) {
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rng_backend_request_entropy(vrng->rng, size, chr_read, vrng);
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}
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}
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static uint32_t get_features(VirtIODevice *vdev, uint32_t f)
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{
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return f;
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}
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static void virtio_rng_save(QEMUFile *f, void *opaque)
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{
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VirtIORNG *vrng = opaque;
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virtio_save(&vrng->vdev, f);
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qemu_put_byte(f, vrng->popped);
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if (vrng->popped) {
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int i;
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qemu_put_be32(f, vrng->elem.index);
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qemu_put_be32(f, vrng->elem.in_num);
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for (i = 0; i < vrng->elem.in_num; i++) {
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qemu_put_be64(f, vrng->elem.in_addr[i]);
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}
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qemu_put_be32(f, vrng->elem.out_num);
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for (i = 0; i < vrng->elem.out_num; i++) {
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qemu_put_be64(f, vrng->elem.out_addr[i]);
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}
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}
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}
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static int virtio_rng_load(QEMUFile *f, void *opaque, int version_id)
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{
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VirtIORNG *vrng = opaque;
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if (version_id != 1) {
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return -EINVAL;
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}
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virtio_load(&vrng->vdev, f);
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vrng->popped = qemu_get_byte(f);
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if (vrng->popped) {
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int i;
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vrng->elem.index = qemu_get_be32(f);
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vrng->elem.in_num = qemu_get_be32(f);
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g_assert(vrng->elem.in_num < VIRTQUEUE_MAX_SIZE);
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for (i = 0; i < vrng->elem.in_num; i++) {
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vrng->elem.in_addr[i] = qemu_get_be64(f);
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}
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vrng->elem.out_num = qemu_get_be32(f);
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g_assert(vrng->elem.out_num < VIRTQUEUE_MAX_SIZE);
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for (i = 0; i < vrng->elem.out_num; i++) {
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vrng->elem.out_addr[i] = qemu_get_be64(f);
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}
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virtqueue_map_sg(vrng->elem.in_sg, vrng->elem.in_addr,
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vrng->elem.in_num, 1);
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virtqueue_map_sg(vrng->elem.out_sg, vrng->elem.out_addr,
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vrng->elem.out_num, 0);
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}
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return 0;
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}
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VirtIODevice *virtio_rng_init(DeviceState *dev, VirtIORNGConf *conf)
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{
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VirtIORNG *vrng;
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VirtIODevice *vdev;
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Error *local_err = NULL;
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vdev = virtio_common_init("virtio-rng", VIRTIO_ID_RNG, 0,
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sizeof(VirtIORNG));
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vrng = DO_UPCAST(VirtIORNG, vdev, vdev);
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vrng->rng = conf->rng;
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if (vrng->rng == NULL) {
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qerror_report(QERR_INVALID_PARAMETER_VALUE, "rng", "a valid object");
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return NULL;
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}
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rng_backend_open(vrng->rng, &local_err);
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if (local_err) {
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qerror_report_err(local_err);
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error_free(local_err);
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return NULL;
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}
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vrng->vq = virtio_add_queue(vdev, 8, handle_input);
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vrng->vdev.get_features = get_features;
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vrng->qdev = dev;
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vrng->conf = conf;
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vrng->popped = false;
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register_savevm(dev, "virtio-rng", -1, 1, virtio_rng_save,
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virtio_rng_load, vrng);
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return vdev;
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}
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void virtio_rng_exit(VirtIODevice *vdev)
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{
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VirtIORNG *vrng = DO_UPCAST(VirtIORNG, vdev, vdev);
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unregister_savevm(vrng->qdev, "virtio-rng", vrng);
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virtio_cleanup(vdev);
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}
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