hw/virtio/vhost-user-scmi.c

   1 /*
   2  * Vhost-user SCMI virtio device
   3  *
   4  * SPDX-FileCopyrightText: Red Hat, Inc.
   5  * SPDX-License-Identifier: GPL-2.0-or-later
   6  *
   7  * Implementation based on other vhost-user devices in QEMU.
   8  */
   9
  10 #include "qemu/osdep.h"
  11 #include "qapi/error.h"
  12 #include "qemu/error-report.h"
  13 #include "hw/virtio/virtio-bus.h"
  14 #include "hw/virtio/vhost-user-scmi.h"
  15 #include "standard-headers/linux/virtio_ids.h"
  16 #include "standard-headers/linux/virtio_scmi.h"
  17 #include "trace.h"
  18
  19 /*
  20  * In this version, we don't support VIRTIO_SCMI_F_SHARED_MEMORY.
  21  * Note that VIRTIO_SCMI_F_SHARED_MEMORY is currently not supported in
  22  * Linux VirtIO SCMI guest driver.
  23  */
  24 static const int feature_bits[] = {
  25     VIRTIO_F_VERSION_1,
  26     VIRTIO_F_NOTIFY_ON_EMPTY,
  27     VIRTIO_RING_F_INDIRECT_DESC,
  28     VIRTIO_RING_F_EVENT_IDX,
  29     VIRTIO_F_RING_RESET,
  30     VIRTIO_SCMI_F_P2A_CHANNELS,
  31     VHOST_INVALID_FEATURE_BIT
  32 };
  33
  34 static int vu_scmi_start(VirtIODevice *vdev)
  35 {
  36     VHostUserSCMI *scmi = VHOST_USER_SCMI(vdev);
  37     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
  38     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
  39     struct vhost_dev *vhost_dev = &scmi->vhost_dev;
  40     int ret, i;
  41
  42     if (!k->set_guest_notifiers) {
  43         error_report("binding does not support guest notifiers");
  44         return -ENOSYS;
  45     }
  46
  47     ret = vhost_dev_enable_notifiers(vhost_dev, vdev);
  48     if (ret < 0) {
  49         error_report("Error enabling host notifiers: %d", ret);
  50         return ret;
  51     }
  52
  53     ret = k->set_guest_notifiers(qbus->parent, vhost_dev->nvqs, true);
  54     if (ret < 0) {
  55         error_report("Error binding guest notifier: %d", ret);
  56         goto err_host_notifiers;
  57     }
  58
  59     vhost_ack_features(&scmi->vhost_dev, feature_bits, vdev->guest_features);
  60
  61     ret = vhost_dev_start(&scmi->vhost_dev, vdev, true);
  62     if (ret < 0) {
  63         error_report("Error starting vhost-user-scmi: %d", ret);
  64         goto err_guest_notifiers;
  65     }
  66     scmi->started_vu = true;
  67
  68     /*
  69      * guest_notifier_mask/pending not used yet, so just unmask
  70      * everything here. virtio-pci will do the right thing by
  71      * enabling/disabling irqfd.
  72      */
  73     for (i = 0; i < scmi->vhost_dev.nvqs; i++) {
  74         vhost_virtqueue_mask(&scmi->vhost_dev, vdev, i, false);
  75     }
  76     return 0;
  77
  78 err_guest_notifiers:
  79     k->set_guest_notifiers(qbus->parent, vhost_dev->nvqs, false);
  80 err_host_notifiers:
  81     vhost_dev_disable_notifiers(vhost_dev, vdev);
  82
  83     return ret;
  84 }
  85
  86 static void vu_scmi_stop(VirtIODevice *vdev)
  87 {
  88     VHostUserSCMI *scmi = VHOST_USER_SCMI(vdev);
  89     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
  90     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
  91     struct vhost_dev *vhost_dev = &scmi->vhost_dev;
  92     int ret;
  93
  94     /* vhost_dev_is_started() check in the callers is not fully reliable. */
  95     if (!scmi->started_vu) {
  96         return;
  97     }
  98     scmi->started_vu = false;
  99
 100     if (!k->set_guest_notifiers) {
 101         return;
 102     }
 103
 104     vhost_dev_stop(vhost_dev, vdev, true);
 105
 106     ret = k->set_guest_notifiers(qbus->parent, vhost_dev->nvqs, false);
 107     if (ret < 0) {
 108         error_report("vhost guest notifier cleanup failed: %d", ret);
 109         return;
 110     }
 111     vhost_dev_disable_notifiers(vhost_dev, vdev);
 112 }
 113
 114 static void vu_scmi_set_status(VirtIODevice *vdev, uint8_t status)
 115 {
 116     VHostUserSCMI *scmi = VHOST_USER_SCMI(vdev);
 117     bool should_start = virtio_device_should_start(vdev, status);
 118
 119     if (!scmi->connected) {
 120         return;
 121     }
 122     if (vhost_dev_is_started(&scmi->vhost_dev) == should_start) {
 123         return;
 124     }
 125
 126     if (should_start) {
 127         vu_scmi_start(vdev);
 128     } else {
 129         vu_scmi_stop(vdev);
 130     }
 131 }
 132
 133 static uint64_t vu_scmi_get_features(VirtIODevice *vdev, uint64_t features,
 134                                      Error **errp)
 135 {
 136     VHostUserSCMI *scmi = VHOST_USER_SCMI(vdev);
 137
 138     return vhost_get_features(&scmi->vhost_dev, feature_bits, features);
 139 }
 140
 141 static void vu_scmi_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 142 {
 143     /*
 144      * Not normally called; it's the daemon that handles the queue;
 145      * however virtio's cleanup path can call this.
 146      */
 147 }
 148
 149 static void vu_scmi_guest_notifier_mask(VirtIODevice *vdev, int idx, bool mask)
 150 {
 151     VHostUserSCMI *scmi = VHOST_USER_SCMI(vdev);
 152
 153     if (idx == VIRTIO_CONFIG_IRQ_IDX) {
 154         return;
 155     }
 156
 157     vhost_virtqueue_mask(&scmi->vhost_dev, vdev, idx, mask);
 158 }
 159
 160 static bool vu_scmi_guest_notifier_pending(VirtIODevice *vdev, int idx)
 161 {
 162     VHostUserSCMI *scmi = VHOST_USER_SCMI(vdev);
 163
 164     return vhost_virtqueue_pending(&scmi->vhost_dev, idx);
 165 }
 166
 167 static void vu_scmi_connect(DeviceState *dev)
 168 {
 169     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 170     VHostUserSCMI *scmi = VHOST_USER_SCMI(vdev);
 171
 172     if (scmi->connected) {
 173         return;
 174     }
 175     scmi->connected = true;
 176
 177     /* restore vhost state */
 178     if (virtio_device_started(vdev, vdev->status)) {
 179         vu_scmi_start(vdev);
 180     }
 181 }
 182
 183 static void vu_scmi_disconnect(DeviceState *dev)
 184 {
 185     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 186     VHostUserSCMI *scmi = VHOST_USER_SCMI(vdev);
 187
 188     if (!scmi->connected) {
 189         return;
 190     }
 191     scmi->connected = false;
 192
 193     if (vhost_dev_is_started(&scmi->vhost_dev)) {
 194         vu_scmi_stop(vdev);
 195     }
 196 }
 197
 198 static void vu_scmi_event(void *opaque, QEMUChrEvent event)
 199 {
 200     DeviceState *dev = opaque;
 201
 202     switch (event) {
 203     case CHR_EVENT_OPENED:
 204         vu_scmi_connect(dev);
 205         break;
 206     case CHR_EVENT_CLOSED:
 207         vu_scmi_disconnect(dev);
 208         break;
 209     case CHR_EVENT_BREAK:
 210     case CHR_EVENT_MUX_IN:
 211     case CHR_EVENT_MUX_OUT:
 212         /* Ignore */
 213         break;
 214     }
 215 }
 216
 217 static void do_vhost_user_cleanup(VirtIODevice *vdev, VHostUserSCMI *scmi)
 218 {
 219     virtio_delete_queue(scmi->cmd_vq);
 220     virtio_delete_queue(scmi->event_vq);
 221     g_free(scmi->vhost_dev.vqs);
 222     virtio_cleanup(vdev);
 223     vhost_user_cleanup(&scmi->vhost_user);
 224 }
 225
 226 static void vu_scmi_device_realize(DeviceState *dev, Error **errp)
 227 {
 228     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 229     VHostUserSCMI *scmi = VHOST_USER_SCMI(dev);
 230     int ret;
 231
 232     if (!scmi->chardev.chr) {
 233         error_setg(errp, "vhost-user-scmi: chardev is mandatory");
 234         return;
 235     }
 236
 237     vdev->host_features |= (1ULL << VIRTIO_SCMI_F_P2A_CHANNELS);
 238
 239     if (!vhost_user_init(&scmi->vhost_user, &scmi->chardev, errp)) {
 240         return;
 241     }
 242
 243     virtio_init(vdev, VIRTIO_ID_SCMI, 0);
 244
 245     scmi->cmd_vq = virtio_add_queue(vdev, 256, vu_scmi_handle_output);
 246     scmi->event_vq = virtio_add_queue(vdev, 256, vu_scmi_handle_output);
 247     scmi->vhost_dev.nvqs = 2;
 248     scmi->vhost_dev.vqs = g_new0(struct vhost_virtqueue, scmi->vhost_dev.nvqs);
 249
 250     ret = vhost_dev_init(&scmi->vhost_dev, &scmi->vhost_user,
 251                          VHOST_BACKEND_TYPE_USER, 0, errp);
 252     if (ret < 0) {
 253         error_setg_errno(errp, -ret,
 254                          "vhost-user-scmi: vhost_dev_init() failed");
 255         do_vhost_user_cleanup(vdev, scmi);
 256         return;
 257     }
 258
 259     qemu_chr_fe_set_handlers(&scmi->chardev, NULL, NULL, vu_scmi_event, NULL,
 260                              dev, NULL, true);
 261
 262     return;
 263 }
 264
 265 static void vu_scmi_device_unrealize(DeviceState *dev)
 266 {
 267     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 268     VHostUserSCMI *scmi = VHOST_USER_SCMI(dev);
 269
 270     vu_scmi_set_status(vdev, 0);
 271     vhost_dev_cleanup(&scmi->vhost_dev);
 272     do_vhost_user_cleanup(vdev, scmi);
 273 }
 274
 275 static const VMStateDescription vu_scmi_vmstate = {
 276     .name = "vhost-user-scmi",
 277     .unmigratable = 1,
 278 };
 279
 280 static Property vu_scmi_properties[] = {
 281     DEFINE_PROP_CHR("chardev", VHostUserSCMI, chardev),
 282     DEFINE_PROP_END_OF_LIST(),
 283 };
 284
 285 static void vu_scmi_class_init(ObjectClass *klass, void *data)
 286 {
 287     DeviceClass *dc = DEVICE_CLASS(klass);
 288     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 289
 290     device_class_set_props(dc, vu_scmi_properties);
 291     dc->vmsd = &vu_scmi_vmstate;
 292     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
 293     vdc->realize = vu_scmi_device_realize;
 294     vdc->unrealize = vu_scmi_device_unrealize;
 295     vdc->get_features = vu_scmi_get_features;
 296     vdc->set_status = vu_scmi_set_status;
 297     vdc->guest_notifier_mask = vu_scmi_guest_notifier_mask;
 298     vdc->guest_notifier_pending = vu_scmi_guest_notifier_pending;
 299 }
 300
 301 static const TypeInfo vu_scmi_info = {
 302     .name = TYPE_VHOST_USER_SCMI,
 303     .parent = TYPE_VIRTIO_DEVICE,
 304     .instance_size = sizeof(VHostUserSCMI),
 305     .class_init = vu_scmi_class_init,
 306 };
 307
 308 static void vu_scmi_register_types(void)
 309 {
 310     type_register_static(&vu_scmi_info);
 311 }
 312
 313 type_init(vu_scmi_register_types)