Following in the footsteps of what whas done for vhost-user-i2c and virtiofsd, introduce a random number generator (RNG) backend that communicates with a vhost-user server to retrieve entropy. That way another VMM could be using the same vhost-user daemon and avoid having to write yet another RNG driver.
Signed-off-by: Mathieu Poirier mathieu.poirier@linaro.org --- hw/virtio/Kconfig | 5 + hw/virtio/meson.build | 1 + hw/virtio/vhost-user-rng.c | 294 +++++++++++++++++++++++++++++ include/hw/virtio/vhost-user-rng.h | 33 ++++ 4 files changed, 333 insertions(+) create mode 100644 hw/virtio/vhost-user-rng.c create mode 100644 include/hw/virtio/vhost-user-rng.h
diff --git a/hw/virtio/Kconfig b/hw/virtio/Kconfig index 0eda25c4e1bf..69066ab14e6d 100644 --- a/hw/virtio/Kconfig +++ b/hw/virtio/Kconfig @@ -58,3 +58,8 @@ config VIRTIO_MEM depends on LINUX depends on VIRTIO_MEM_SUPPORTED select MEM_DEVICE + +config VHOST_USER_RNG + bool + default y + depends on VIRTIO && VHOST_USER diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build index fbff9bc9d4de..e386791f2a05 100644 --- a/hw/virtio/meson.build +++ b/hw/virtio/meson.build @@ -25,6 +25,7 @@ virtio_ss.add(when: 'CONFIG_VHOST_USER_VSOCK', if_true: files('vhost-user-vsock. virtio_ss.add(when: 'CONFIG_VIRTIO_RNG', if_true: files('virtio-rng.c')) virtio_ss.add(when: 'CONFIG_VIRTIO_IOMMU', if_true: files('virtio-iommu.c')) virtio_ss.add(when: 'CONFIG_VIRTIO_MEM', if_true: files('virtio-mem.c')) +virtio_ss.add(when: 'CONFIG_VHOST_USER_RNG', if_true: files('vhost-user-rng.c'))
virtio_pci_ss = ss.source_set() virtio_pci_ss.add(when: 'CONFIG_VHOST_VSOCK', if_true: files('vhost-vsock-pci.c')) diff --git a/hw/virtio/vhost-user-rng.c b/hw/virtio/vhost-user-rng.c new file mode 100644 index 000000000000..78447e8d3791 --- /dev/null +++ b/hw/virtio/vhost-user-rng.c @@ -0,0 +1,294 @@ +/* + * Vhost-user RNG virtio device + * + * Copyright (c) 2021 Mathieu Poirier mathieu.poirier@linaro.org + * + * Implementation seriously tailored on vhost-user-i2c.c + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ + +#include "qemu/osdep.h" +#include "qapi/error.h" +#include "hw/qdev-properties.h" +#include "hw/virtio/virtio-bus.h" +#include "hw/virtio/vhost-user-rng.h" +#include "qemu/error-report.h" +#include "standard-headers/linux/virtio_ids.h" + +static void vu_rng_start(VirtIODevice *vdev) +{ + VHostUserRNG *rng = VHOST_USER_RNG(vdev); + BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev))); + VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); + int ret; + int i; + + if (!k->set_guest_notifiers) { + error_report("binding does not support guest notifiers"); + return; + } + + ret = vhost_dev_enable_notifiers(&rng->vhost_dev, vdev); + if (ret < 0) { + error_report("Error enabling host notifiers: %d", -ret); + return; + } + + ret = k->set_guest_notifiers(qbus->parent, rng->vhost_dev.nvqs, true); + if (ret < 0) { + error_report("Error binding guest notifier: %d", -ret); + goto err_host_notifiers; + } + + rng->vhost_dev.acked_features = vdev->guest_features; + ret = vhost_dev_start(&rng->vhost_dev, vdev); + if (ret < 0) { + error_report("Error starting vhost-user-rng: %d", -ret); + goto err_guest_notifiers; + } + + /* + * guest_notifier_mask/pending not used yet, so just unmask + * everything here. virtio-pci will do the right thing by + * enabling/disabling irqfd. + */ + for (i = 0; i < rng->vhost_dev.nvqs; i++) { + vhost_virtqueue_mask(&rng->vhost_dev, vdev, i, false); + } + + return; + +err_guest_notifiers: + k->set_guest_notifiers(qbus->parent, rng->vhost_dev.nvqs, false); +err_host_notifiers: + vhost_dev_disable_notifiers(&rng->vhost_dev, vdev); +} + +static void vu_rng_stop(VirtIODevice *vdev) +{ + VHostUserRNG *rng = VHOST_USER_RNG(vdev); + BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev))); + VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); + int ret; + + if (!k->set_guest_notifiers) { + return; + } + + vhost_dev_stop(&rng->vhost_dev, vdev); + + ret = k->set_guest_notifiers(qbus->parent, rng->vhost_dev.nvqs, false); + if (ret < 0) { + error_report("vhost guest notifier cleanup failed: %d", ret); + return; + } + + vhost_dev_disable_notifiers(&rng->vhost_dev, vdev); +} + +static void vu_rng_set_status(VirtIODevice *vdev, uint8_t status) +{ + VHostUserRNG *rng = VHOST_USER_RNG(vdev); + bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK; + + if (!vdev->vm_running) { + should_start = false; + } + + if (rng->vhost_dev.started == should_start) { + return; + } + + if (should_start) { + vu_rng_start(vdev); + } else { + vu_rng_stop(vdev); + } +} + +static uint64_t vu_rng_get_features(VirtIODevice *vdev, + uint64_t requested_features, Error **errp) +{ + /* No feature bits used yet */ + return requested_features; +} + +static void vu_rng_handle_output(VirtIODevice *vdev, VirtQueue *vq) +{ + /* + * Not normally called; it's the daemon that handles the queue; + * however virtio's cleanup path can call this. + */ +} + +static void vu_rng_guest_notifier_mask(VirtIODevice *vdev, int idx, bool mask) +{ + VHostUserRNG *rng = VHOST_USER_RNG(vdev); + + vhost_virtqueue_mask(&rng->vhost_dev, vdev, idx, mask); +} + +static bool vu_rng_guest_notifier_pending(VirtIODevice *vdev, int idx) +{ + VHostUserRNG *rng = VHOST_USER_RNG(vdev); + + return vhost_virtqueue_pending(&rng->vhost_dev, idx); +} + +static void vu_rng_connect(DeviceState *dev) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VHostUserRNG *rng = VHOST_USER_RNG(vdev); + + if (rng->connected) { + return; + } + + rng->connected = true; + + /* restore vhost state */ + if (virtio_device_started(vdev, vdev->status)) { + vu_rng_start(vdev); + } +} + +static void vu_rng_disconnect(DeviceState *dev) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VHostUserRNG *rng = VHOST_USER_RNG(vdev); + + if (!rng->connected) { + return; + } + + rng->connected = false; + + if (rng->vhost_dev.started) { + vu_rng_stop(vdev); + } +} + +static void vu_rng_event(void *opaque, QEMUChrEvent event) +{ + DeviceState *dev = opaque; + + switch (event) { + case CHR_EVENT_OPENED: + vu_rng_connect(dev); + break; + case CHR_EVENT_CLOSED: + vu_rng_disconnect(dev); + break; + case CHR_EVENT_BREAK: + case CHR_EVENT_MUX_IN: + case CHR_EVENT_MUX_OUT: + /* Ignore */ + break; + } +} + +static void vu_rng_device_realize(DeviceState *dev, Error **errp) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VHostUserRNG *rng = VHOST_USER_RNG(dev); + int ret; + + if (!rng->chardev.chr) { + error_setg(errp, "missing chardev"); + return; + } + + if (!vhost_user_init(&rng->vhost_user, &rng->chardev, errp)) { + return; + } + + virtio_init(vdev, "vhost-user-rng", VIRTIO_ID_RNG, 0); + + rng->req_vq = virtio_add_queue(vdev, 4, vu_rng_handle_output); + if (!rng->req_vq) { + error_setg_errno(errp, -1, "virtio_add_queue() failed"); + goto virtio_add_queue_failed; + } + + rng->vhost_dev.nvqs = 1; + rng->vhost_dev.vqs = g_new0(struct vhost_virtqueue, rng->vhost_dev.nvqs); + if (!rng->vhost_dev.vqs) { + error_setg_errno(errp, -1, "memory allocation failed"); + goto vhost_dev_init_failed; + } + + ret = vhost_dev_init(&rng->vhost_dev, &rng->vhost_user, + VHOST_BACKEND_TYPE_USER, 0); + if (ret < 0) { + error_setg_errno(errp, -ret, "vhost_dev_init() failed"); + goto vhost_dev_init_failed; + } + + qemu_chr_fe_set_handlers(&rng->chardev, NULL, NULL, vu_rng_event, NULL, + dev, NULL, true); + + return; + +vhost_dev_init_failed: + virtio_delete_queue(rng->req_vq); +virtio_add_queue_failed: + virtio_cleanup(vdev); + vhost_user_cleanup(&rng->vhost_user); +} + +static void vu_rng_device_unrealize(DeviceState *dev) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VHostUserRNG *rng = VHOST_USER_RNG(dev); + + vu_rng_set_status(vdev, 0); + + vhost_dev_cleanup(&rng->vhost_dev); + g_free(rng->vhost_dev.vqs); + rng->vhost_dev.vqs = NULL; + virtio_delete_queue(rng->req_vq); + virtio_cleanup(vdev); + vhost_user_cleanup(&rng->vhost_user); +} + +static const VMStateDescription vu_rng_vmstate = { + .name = "vhost-user-rng", + .unmigratable = 1, +}; + +static Property vu_rng_properties[] = { + DEFINE_PROP_CHR("chardev", VHostUserRNG, chardev), + DEFINE_PROP_END_OF_LIST(), +}; + +static void vu_rng_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); + + device_class_set_props(dc, vu_rng_properties); + dc->vmsd = &vu_rng_vmstate; + set_bit(DEVICE_CATEGORY_INPUT, dc->categories); + + vdc->realize = vu_rng_device_realize; + vdc->unrealize = vu_rng_device_unrealize; + vdc->get_features = vu_rng_get_features; + vdc->set_status = vu_rng_set_status; + vdc->guest_notifier_mask = vu_rng_guest_notifier_mask; + vdc->guest_notifier_pending = vu_rng_guest_notifier_pending; +} + +static const TypeInfo vu_rng_info = { + .name = TYPE_VHOST_USER_RNG, + .parent = TYPE_VIRTIO_DEVICE, + .instance_size = sizeof(VHostUserRNG), + .class_init = vu_rng_class_init, +}; + +static void vu_rng_register_types(void) +{ + type_register_static(&vu_rng_info); +} + +type_init(vu_rng_register_types) diff --git a/include/hw/virtio/vhost-user-rng.h b/include/hw/virtio/vhost-user-rng.h new file mode 100644 index 000000000000..071539996d1d --- /dev/null +++ b/include/hw/virtio/vhost-user-rng.h @@ -0,0 +1,33 @@ +/* + * Vhost-user RNG virtio device + * + * Copyright (c) 2021 Mathieu Poirier mathieu.poirier@linaro.org + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ + +#ifndef _QEMU_VHOST_USER_RNG_H +#define _QEMU_VHOST_USER_RNG_H + +#include "hw/virtio/virtio.h" +#include "hw/virtio/vhost.h" +#include "hw/virtio/vhost-user.h" +#include "chardev/char-fe.h" + +#define TYPE_VHOST_USER_RNG "vhost-user-rng" +OBJECT_DECLARE_SIMPLE_TYPE(VHostUserRNG, VHOST_USER_RNG) + +struct VHostUserRNG { + /*< private >*/ + VirtIODevice parent; + CharBackend chardev; + struct vhost_virtqueue *vhost_vq; + struct vhost_dev vhost_dev; + VhostUserState vhost_user; + VirtQueue *req_vq; + bool connected; + + /*< public >*/ +}; + +#endif /* _QEMU_VHOST_USER_RNG_H */