vhost-user-rng: Add vhost-user-rng implementation
Introduce a random number generator (RNG) backend that communicates with a vhost-user server to retrieve entropy. That way other VMM that comply with the vhost user protocl can use the same vhost-user daemon without having to write yet another RNG driver. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> Message-Id: <20211012205904.4106769-2-mathieu.poirier@linaro.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Mathieu Poirier
Michael S. Tsirkin
parent
6889eb2d43
commit
821d28b88f
@ -63,3 +63,8 @@ config VHOST_USER_I2C
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bool
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default y
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depends on VIRTIO && VHOST_USER
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config VHOST_USER_RNG
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bool
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default y
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depends on VIRTIO && VHOST_USER
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@ -27,6 +27,7 @@ virtio_ss.add(when: 'CONFIG_VIRTIO_IOMMU', if_true: files('virtio-iommu.c'))
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virtio_ss.add(when: 'CONFIG_VIRTIO_MEM', if_true: files('virtio-mem.c'))
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virtio_ss.add(when: 'CONFIG_VHOST_USER_I2C', if_true: files('vhost-user-i2c.c'))
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virtio_ss.add(when: ['CONFIG_VIRTIO_PCI', 'CONFIG_VHOST_USER_I2C'], if_true: files('vhost-user-i2c-pci.c'))
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virtio_ss.add(when: 'CONFIG_VHOST_USER_RNG', if_true: files('vhost-user-rng.c'))
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virtio_pci_ss = ss.source_set()
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virtio_pci_ss.add(when: 'CONFIG_VHOST_VSOCK', if_true: files('vhost-vsock-pci.c'))
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289
hw/virtio/vhost-user-rng.c
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289
hw/virtio/vhost-user-rng.c
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@ -0,0 +1,289 @@
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/*
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* Vhost-user RNG virtio device
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*
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* Copyright (c) 2021 Mathieu Poirier <mathieu.poirier@linaro.org>
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*
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* Implementation seriously tailored on vhost-user-i2c.c
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "qemu/osdep.h"
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#include "qapi/error.h"
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#include "hw/qdev-properties.h"
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#include "hw/virtio/virtio-bus.h"
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#include "hw/virtio/vhost-user-rng.h"
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#include "qemu/error-report.h"
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#include "standard-headers/linux/virtio_ids.h"
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static void vu_rng_start(VirtIODevice *vdev)
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{
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VHostUserRNG *rng = VHOST_USER_RNG(vdev);
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BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
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VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
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int ret;
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int i;
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if (!k->set_guest_notifiers) {
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error_report("binding does not support guest notifiers");
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return;
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}
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ret = vhost_dev_enable_notifiers(&rng->vhost_dev, vdev);
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if (ret < 0) {
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error_report("Error enabling host notifiers: %d", -ret);
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return;
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}
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ret = k->set_guest_notifiers(qbus->parent, rng->vhost_dev.nvqs, true);
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if (ret < 0) {
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error_report("Error binding guest notifier: %d", -ret);
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goto err_host_notifiers;
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}
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rng->vhost_dev.acked_features = vdev->guest_features;
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ret = vhost_dev_start(&rng->vhost_dev, vdev);
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if (ret < 0) {
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error_report("Error starting vhost-user-rng: %d", -ret);
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goto err_guest_notifiers;
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}
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/*
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* guest_notifier_mask/pending not used yet, so just unmask
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* everything here. virtio-pci will do the right thing by
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* enabling/disabling irqfd.
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*/
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for (i = 0; i < rng->vhost_dev.nvqs; i++) {
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vhost_virtqueue_mask(&rng->vhost_dev, vdev, i, false);
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}
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return;
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err_guest_notifiers:
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k->set_guest_notifiers(qbus->parent, rng->vhost_dev.nvqs, false);
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err_host_notifiers:
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vhost_dev_disable_notifiers(&rng->vhost_dev, vdev);
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}
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static void vu_rng_stop(VirtIODevice *vdev)
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{
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VHostUserRNG *rng = VHOST_USER_RNG(vdev);
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BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
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VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
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int ret;
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if (!k->set_guest_notifiers) {
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return;
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}
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vhost_dev_stop(&rng->vhost_dev, vdev);
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ret = k->set_guest_notifiers(qbus->parent, rng->vhost_dev.nvqs, false);
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if (ret < 0) {
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error_report("vhost guest notifier cleanup failed: %d", ret);
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return;
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}
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vhost_dev_disable_notifiers(&rng->vhost_dev, vdev);
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}
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static void vu_rng_set_status(VirtIODevice *vdev, uint8_t status)
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{
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VHostUserRNG *rng = VHOST_USER_RNG(vdev);
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bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
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if (!vdev->vm_running) {
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should_start = false;
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}
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if (rng->vhost_dev.started == should_start) {
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return;
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}
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if (should_start) {
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vu_rng_start(vdev);
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} else {
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vu_rng_stop(vdev);
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}
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}
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static uint64_t vu_rng_get_features(VirtIODevice *vdev,
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uint64_t requested_features, Error **errp)
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{
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/* No feature bits used yet */
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return requested_features;
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}
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static void vu_rng_handle_output(VirtIODevice *vdev, VirtQueue *vq)
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{
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/*
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* Not normally called; it's the daemon that handles the queue;
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* however virtio's cleanup path can call this.
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*/
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}
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static void vu_rng_guest_notifier_mask(VirtIODevice *vdev, int idx, bool mask)
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{
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VHostUserRNG *rng = VHOST_USER_RNG(vdev);
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vhost_virtqueue_mask(&rng->vhost_dev, vdev, idx, mask);
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}
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static bool vu_rng_guest_notifier_pending(VirtIODevice *vdev, int idx)
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{
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VHostUserRNG *rng = VHOST_USER_RNG(vdev);
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return vhost_virtqueue_pending(&rng->vhost_dev, idx);
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}
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static void vu_rng_connect(DeviceState *dev)
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{
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VirtIODevice *vdev = VIRTIO_DEVICE(dev);
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VHostUserRNG *rng = VHOST_USER_RNG(vdev);
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if (rng->connected) {
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return;
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}
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rng->connected = true;
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/* restore vhost state */
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if (virtio_device_started(vdev, vdev->status)) {
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vu_rng_start(vdev);
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}
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}
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static void vu_rng_disconnect(DeviceState *dev)
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{
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VirtIODevice *vdev = VIRTIO_DEVICE(dev);
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VHostUserRNG *rng = VHOST_USER_RNG(vdev);
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if (!rng->connected) {
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return;
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}
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rng->connected = false;
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if (rng->vhost_dev.started) {
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vu_rng_stop(vdev);
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}
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}
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static void vu_rng_event(void *opaque, QEMUChrEvent event)
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{
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DeviceState *dev = opaque;
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switch (event) {
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case CHR_EVENT_OPENED:
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vu_rng_connect(dev);
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break;
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case CHR_EVENT_CLOSED:
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vu_rng_disconnect(dev);
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break;
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case CHR_EVENT_BREAK:
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case CHR_EVENT_MUX_IN:
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case CHR_EVENT_MUX_OUT:
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/* Ignore */
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break;
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}
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}
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static void vu_rng_device_realize(DeviceState *dev, Error **errp)
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{
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VirtIODevice *vdev = VIRTIO_DEVICE(dev);
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VHostUserRNG *rng = VHOST_USER_RNG(dev);
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int ret;
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if (!rng->chardev.chr) {
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error_setg(errp, "missing chardev");
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return;
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}
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if (!vhost_user_init(&rng->vhost_user, &rng->chardev, errp)) {
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return;
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}
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virtio_init(vdev, "vhost-user-rng", VIRTIO_ID_RNG, 0);
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rng->req_vq = virtio_add_queue(vdev, 4, vu_rng_handle_output);
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if (!rng->req_vq) {
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error_setg_errno(errp, -1, "virtio_add_queue() failed");
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goto virtio_add_queue_failed;
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}
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rng->vhost_dev.nvqs = 1;
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rng->vhost_dev.vqs = g_new0(struct vhost_virtqueue, rng->vhost_dev.nvqs);
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ret = vhost_dev_init(&rng->vhost_dev, &rng->vhost_user,
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VHOST_BACKEND_TYPE_USER, 0, errp);
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if (ret < 0) {
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error_setg_errno(errp, -ret, "vhost_dev_init() failed");
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goto vhost_dev_init_failed;
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}
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qemu_chr_fe_set_handlers(&rng->chardev, NULL, NULL, vu_rng_event, NULL,
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dev, NULL, true);
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return;
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vhost_dev_init_failed:
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virtio_delete_queue(rng->req_vq);
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virtio_add_queue_failed:
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virtio_cleanup(vdev);
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vhost_user_cleanup(&rng->vhost_user);
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}
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static void vu_rng_device_unrealize(DeviceState *dev)
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{
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VirtIODevice *vdev = VIRTIO_DEVICE(dev);
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VHostUserRNG *rng = VHOST_USER_RNG(dev);
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vu_rng_set_status(vdev, 0);
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vhost_dev_cleanup(&rng->vhost_dev);
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g_free(rng->vhost_dev.vqs);
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rng->vhost_dev.vqs = NULL;
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virtio_delete_queue(rng->req_vq);
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virtio_cleanup(vdev);
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vhost_user_cleanup(&rng->vhost_user);
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}
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static const VMStateDescription vu_rng_vmstate = {
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.name = "vhost-user-rng",
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.unmigratable = 1,
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};
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static Property vu_rng_properties[] = {
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DEFINE_PROP_CHR("chardev", VHostUserRNG, chardev),
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DEFINE_PROP_END_OF_LIST(),
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};
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static void vu_rng_class_init(ObjectClass *klass, void *data)
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{
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DeviceClass *dc = DEVICE_CLASS(klass);
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VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
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device_class_set_props(dc, vu_rng_properties);
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dc->vmsd = &vu_rng_vmstate;
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set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
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vdc->realize = vu_rng_device_realize;
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vdc->unrealize = vu_rng_device_unrealize;
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vdc->get_features = vu_rng_get_features;
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vdc->set_status = vu_rng_set_status;
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vdc->guest_notifier_mask = vu_rng_guest_notifier_mask;
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vdc->guest_notifier_pending = vu_rng_guest_notifier_pending;
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}
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static const TypeInfo vu_rng_info = {
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.name = TYPE_VHOST_USER_RNG,
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.parent = TYPE_VIRTIO_DEVICE,
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.instance_size = sizeof(VHostUserRNG),
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.class_init = vu_rng_class_init,
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};
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static void vu_rng_register_types(void)
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{
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type_register_static(&vu_rng_info);
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}
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type_init(vu_rng_register_types)
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33
include/hw/virtio/vhost-user-rng.h
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33
include/hw/virtio/vhost-user-rng.h
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@ -0,0 +1,33 @@
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/*
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* Vhost-user RNG virtio device
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*
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* Copyright (c) 2021 Mathieu Poirier <mathieu.poirier@linaro.org>
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#ifndef _QEMU_VHOST_USER_RNG_H
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#define _QEMU_VHOST_USER_RNG_H
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#include "hw/virtio/virtio.h"
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#include "hw/virtio/vhost.h"
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#include "hw/virtio/vhost-user.h"
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#include "chardev/char-fe.h"
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#define TYPE_VHOST_USER_RNG "vhost-user-rng"
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OBJECT_DECLARE_SIMPLE_TYPE(VHostUserRNG, VHOST_USER_RNG)
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struct VHostUserRNG {
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/*< private >*/
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VirtIODevice parent;
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CharBackend chardev;
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struct vhost_virtqueue *vhost_vq;
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struct vhost_dev vhost_dev;
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VhostUserState vhost_user;
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VirtQueue *req_vq;
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bool connected;
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/*< public >*/
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};
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#endif /* _QEMU_VHOST_USER_RNG_H */
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