diff options
Diffstat (limited to 'hw/virtio/vhost-user-device.c')
| -rw-r--r-- | hw/virtio/vhost-user-device.c | 380 |
1 files changed, 380 insertions, 0 deletions
diff --git a/hw/virtio/vhost-user-device.c b/hw/virtio/vhost-user-device.c new file mode 100644 index 0000000000..2b028cae08 --- /dev/null +++ b/hw/virtio/vhost-user-device.c @@ -0,0 +1,380 @@ +/* + * Generic vhost-user stub. This can be used to connect to any + * vhost-user backend. All configuration details must be handled by + * the vhost-user daemon itself + * + * Copyright (c) 2023 Linaro Ltd + * Author: Alex Bennée <alex.bennee@linaro.org> + * + * 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-device.h" +#include "qemu/error-report.h" + +static void vub_start(VirtIODevice *vdev) +{ + BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev))); + VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); + VHostUserBase *vub = VHOST_USER_BASE(vdev); + int ret, i; + + if (!k->set_guest_notifiers) { + error_report("binding does not support guest notifiers"); + return; + } + + ret = vhost_dev_enable_notifiers(&vub->vhost_dev, vdev); + if (ret < 0) { + error_report("Error enabling host notifiers: %d", -ret); + return; + } + + ret = k->set_guest_notifiers(qbus->parent, vub->vhost_dev.nvqs, true); + if (ret < 0) { + error_report("Error binding guest notifier: %d", -ret); + goto err_host_notifiers; + } + + vub->vhost_dev.acked_features = vdev->guest_features; + + ret = vhost_dev_start(&vub->vhost_dev, vdev, true); + if (ret < 0) { + error_report("Error starting vhost-user-device: %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 < vub->vhost_dev.nvqs; i++) { + vhost_virtqueue_mask(&vub->vhost_dev, vdev, i, false); + } + + return; + +err_guest_notifiers: + k->set_guest_notifiers(qbus->parent, vub->vhost_dev.nvqs, false); +err_host_notifiers: + vhost_dev_disable_notifiers(&vub->vhost_dev, vdev); +} + +static void vub_stop(VirtIODevice *vdev) +{ + VHostUserBase *vub = VHOST_USER_BASE(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(&vub->vhost_dev, vdev, true); + + ret = k->set_guest_notifiers(qbus->parent, vub->vhost_dev.nvqs, false); + if (ret < 0) { + error_report("vhost guest notifier cleanup failed: %d", ret); + return; + } + + vhost_dev_disable_notifiers(&vub->vhost_dev, vdev); +} + +static void vub_set_status(VirtIODevice *vdev, uint8_t status) +{ + VHostUserBase *vub = VHOST_USER_BASE(vdev); + bool should_start = virtio_device_should_start(vdev, status); + + if (vhost_dev_is_started(&vub->vhost_dev) == should_start) { + return; + } + + if (should_start) { + vub_start(vdev); + } else { + vub_stop(vdev); + } +} + +/* + * For an implementation where everything is delegated to the backend + * we don't do anything other than return the full feature set offered + * by the daemon (module the reserved feature bit). + */ +static uint64_t vub_get_features(VirtIODevice *vdev, + uint64_t requested_features, Error **errp) +{ + VHostUserBase *vub = VHOST_USER_BASE(vdev); + /* This should be set when the vhost connection initialises */ + g_assert(vub->vhost_dev.features); + return vub->vhost_dev.features & ~(1ULL << VHOST_USER_F_PROTOCOL_FEATURES); +} + +/* + * To handle VirtIO config we need to know the size of the config + * space. We don't cache the config but re-fetch it from the guest + * every time in case something has changed. + */ +static void vub_get_config(VirtIODevice *vdev, uint8_t *config) +{ + VHostUserBase *vub = VHOST_USER_BASE(vdev); + Error *local_err = NULL; + + /* + * There will have been a warning during vhost_dev_init, but lets + * assert here as nothing will go right now. + */ + g_assert(vub->config_size && vub->vhost_user.supports_config == true); + + if (vhost_dev_get_config(&vub->vhost_dev, config, + vub->config_size, &local_err)) { + error_report_err(local_err); + } +} + +/* + * When the daemon signals an update to the config we just need to + * signal the guest as we re-read the config on demand above. + */ +static int vub_config_notifier(struct vhost_dev *dev) +{ + virtio_notify_config(dev->vdev); + return 0; +} + +const VhostDevConfigOps vub_config_ops = { + .vhost_dev_config_notifier = vub_config_notifier, +}; + +static void vub_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 do_vhost_user_cleanup(VirtIODevice *vdev, VHostUserBase *vub) +{ + vhost_user_cleanup(&vub->vhost_user); + + for (int i = 0; i < vub->num_vqs; i++) { + VirtQueue *vq = g_ptr_array_index(vub->vqs, i); + virtio_delete_queue(vq); + } + + virtio_cleanup(vdev); +} + +static int vub_connect(DeviceState *dev) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VHostUserBase *vub = VHOST_USER_BASE(vdev); + struct vhost_dev *vhost_dev = &vub->vhost_dev; + + if (vub->connected) { + return 0; + } + vub->connected = true; + + /* + * If we support VHOST_USER_GET_CONFIG we must enable the notifier + * so we can ping the guest when it updates. + */ + if (vub->vhost_user.supports_config) { + vhost_dev_set_config_notifier(vhost_dev, &vub_config_ops); + } + + /* restore vhost state */ + if (virtio_device_started(vdev, vdev->status)) { + vub_start(vdev); + } + + return 0; +} + +static void vub_disconnect(DeviceState *dev) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VHostUserBase *vub = VHOST_USER_BASE(vdev); + + if (!vub->connected) { + return; + } + vub->connected = false; + + if (vhost_dev_is_started(&vub->vhost_dev)) { + vub_stop(vdev); + } +} + +static void vub_event(void *opaque, QEMUChrEvent event) +{ + DeviceState *dev = opaque; + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VHostUserBase *vub = VHOST_USER_BASE(vdev); + + switch (event) { + case CHR_EVENT_OPENED: + if (vub_connect(dev) < 0) { + qemu_chr_fe_disconnect(&vub->chardev); + return; + } + break; + case CHR_EVENT_CLOSED: + vub_disconnect(dev); + break; + case CHR_EVENT_BREAK: + case CHR_EVENT_MUX_IN: + case CHR_EVENT_MUX_OUT: + /* Ignore */ + break; + } +} + +static void vub_device_realize(DeviceState *dev, Error **errp) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VHostUserBase *vub = VHOST_USER_BASE(dev); + int ret; + + if (!vub->chardev.chr) { + error_setg(errp, "vhost-user-device: missing chardev"); + return; + } + + if (!vub->virtio_id) { + error_setg(errp, "vhost-user-device: need to define device id"); + return; + } + + if (!vub->num_vqs) { + vub->num_vqs = 1; /* reasonable default? */ + } + + /* + * We can't handle config requests unless we know the size of the + * config region, specialisations of the vhost-user-device will be + * able to set this. + */ + if (vub->config_size) { + vub->vhost_user.supports_config = true; + } + + if (!vhost_user_init(&vub->vhost_user, &vub->chardev, errp)) { + return; + } + + virtio_init(vdev, vub->virtio_id, vub->config_size); + + /* + * Disable guest notifiers, by default all notifications will be via the + * asynchronous vhost-user socket. + */ + vdev->use_guest_notifier_mask = false; + + /* Allocate queues */ + vub->vqs = g_ptr_array_sized_new(vub->num_vqs); + for (int i = 0; i < vub->num_vqs; i++) { + g_ptr_array_add(vub->vqs, + virtio_add_queue(vdev, 4, vub_handle_output)); + } + + vub->vhost_dev.nvqs = vub->num_vqs; + vub->vhost_dev.vqs = g_new0(struct vhost_virtqueue, vub->vhost_dev.nvqs); + + /* connect to backend */ + ret = vhost_dev_init(&vub->vhost_dev, &vub->vhost_user, + VHOST_BACKEND_TYPE_USER, 0, errp); + + if (ret < 0) { + do_vhost_user_cleanup(vdev, vub); + } + + qemu_chr_fe_set_handlers(&vub->chardev, NULL, NULL, vub_event, NULL, + dev, NULL, true); +} + +static void vub_device_unrealize(DeviceState *dev) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(dev); + VHostUserBase *vub = VHOST_USER_BASE(dev); + struct vhost_virtqueue *vhost_vqs = vub->vhost_dev.vqs; + + /* This will stop vhost backend if appropriate. */ + vub_set_status(vdev, 0); + vhost_dev_cleanup(&vub->vhost_dev); + g_free(vhost_vqs); + do_vhost_user_cleanup(vdev, vub); +} + +static void vub_class_init(ObjectClass *klass, void *data) +{ + VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); + + vdc->realize = vub_device_realize; + vdc->unrealize = vub_device_unrealize; + vdc->get_features = vub_get_features; + vdc->get_config = vub_get_config; + vdc->set_status = vub_set_status; +} + +static const TypeInfo vub_info = { + .name = TYPE_VHOST_USER_BASE, + .parent = TYPE_VIRTIO_DEVICE, + .instance_size = sizeof(VHostUserBase), + .class_init = vub_class_init, + .class_size = sizeof(VHostUserBaseClass), + .abstract = true +}; + + +/* + * The following is a concrete implementation of the base class which + * allows the user to define the key parameters via the command line. + */ + +static const VMStateDescription vud_vmstate = { + .name = "vhost-user-device", + .unmigratable = 1, +}; + +static Property vud_properties[] = { + DEFINE_PROP_CHR("chardev", VHostUserBase, chardev), + DEFINE_PROP_UINT16("virtio-id", VHostUserBase, virtio_id, 0), + DEFINE_PROP_UINT32("num_vqs", VHostUserBase, num_vqs, 1), + DEFINE_PROP_UINT32("config_size", VHostUserBase, config_size, 0), + DEFINE_PROP_END_OF_LIST(), +}; + +static void vud_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + + device_class_set_props(dc, vud_properties); + dc->vmsd = &vud_vmstate; + set_bit(DEVICE_CATEGORY_INPUT, dc->categories); +} + +static const TypeInfo vud_info = { + .name = TYPE_VHOST_USER_DEVICE, + .parent = TYPE_VHOST_USER_BASE, + .instance_size = sizeof(VHostUserBase), + .class_init = vud_class_init, + .class_size = sizeof(VHostUserBaseClass), +}; + +static void vu_register_types(void) +{ + type_register_static(&vub_info); + type_register_static(&vud_info); +} + +type_init(vu_register_types) |