hw/virtio/vhost-vsock.c

   1 /*
   2  * Virtio vsock device
   3  *
   4  * Copyright 2015 Red Hat, Inc.
   5  *
   6  * Authors:
   7  *  Stefan Hajnoczi <stefanha@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or
  10  * (at your option) any later version.  See the COPYING file in the
  11  * top-level directory.
  12  */
  13
  14 #include "qemu/osdep.h"
  15 #include <sys/ioctl.h>
  16 #include "standard-headers/linux/virtio_vsock.h"
  17 #include "qapi/error.h"
  18 #include "hw/virtio/virtio-bus.h"
  19 #include "hw/virtio/virtio-access.h"
  20 #include "qemu/error-report.h"
  21 #include "hw/virtio/vhost-vsock.h"
  22 #include "qemu/iov.h"
  23 #include "monitor/monitor.h"
  24
  25 enum {
  26     VHOST_VSOCK_SAVEVM_VERSION = 0,
  27
  28     VHOST_VSOCK_QUEUE_SIZE = 128,
  29 };
  30
  31 static void vhost_vsock_get_config(VirtIODevice *vdev, uint8_t *config)
  32 {
  33     VHostVSock *vsock = VHOST_VSOCK(vdev);
  34     struct virtio_vsock_config vsockcfg = {};
  35
  36     virtio_stq_p(vdev, &vsockcfg.guest_cid, vsock->conf.guest_cid);
  37     memcpy(config, &vsockcfg, sizeof(vsockcfg));
  38 }
  39
  40 static int vhost_vsock_set_guest_cid(VHostVSock *vsock)
  41 {
  42     const VhostOps *vhost_ops = vsock->vhost_dev.vhost_ops;
  43     int ret;
  44
  45     if (!vhost_ops->vhost_vsock_set_guest_cid) {
  46         return -ENOSYS;
  47     }
  48
  49     ret = vhost_ops->vhost_vsock_set_guest_cid(&vsock->vhost_dev,
  50                                                vsock->conf.guest_cid);
  51     if (ret < 0) {
  52         return -errno;
  53     }
  54     return 0;
  55 }
  56
  57 static int vhost_vsock_set_running(VHostVSock *vsock, int start)
  58 {
  59     const VhostOps *vhost_ops = vsock->vhost_dev.vhost_ops;
  60     int ret;
  61
  62     if (!vhost_ops->vhost_vsock_set_running) {
  63         return -ENOSYS;
  64     }
  65
  66     ret = vhost_ops->vhost_vsock_set_running(&vsock->vhost_dev, start);
  67     if (ret < 0) {
  68         return -errno;
  69     }
  70     return 0;
  71 }
  72
  73 static void vhost_vsock_start(VirtIODevice *vdev)
  74 {
  75     VHostVSock *vsock = VHOST_VSOCK(vdev);
  76     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
  77     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
  78     int ret;
  79     int i;
  80
  81     if (!k->set_guest_notifiers) {
  82         error_report("binding does not support guest notifiers");
  83         return;
  84     }
  85
  86     ret = vhost_dev_enable_notifiers(&vsock->vhost_dev, vdev);
  87     if (ret < 0) {
  88         error_report("Error enabling host notifiers: %d", -ret);
  89         return;
  90     }
  91
  92     ret = k->set_guest_notifiers(qbus->parent, vsock->vhost_dev.nvqs, true);
  93     if (ret < 0) {
  94         error_report("Error binding guest notifier: %d", -ret);
  95         goto err_host_notifiers;
  96     }
  97
  98     vsock->vhost_dev.acked_features = vdev->guest_features;
  99     ret = vhost_dev_start(&vsock->vhost_dev, vdev);
 100     if (ret < 0) {
 101         error_report("Error starting vhost: %d", -ret);
 102         goto err_guest_notifiers;
 103     }
 104
 105     ret = vhost_vsock_set_running(vsock, 1);
 106     if (ret < 0) {
 107         error_report("Error starting vhost vsock: %d", -ret);
 108         goto err_dev_start;
 109     }
 110
 111     /* guest_notifier_mask/pending not used yet, so just unmask
 112      * everything here.  virtio-pci will do the right thing by
 113      * enabling/disabling irqfd.
 114      */
 115     for (i = 0; i < vsock->vhost_dev.nvqs; i++) {
 116         vhost_virtqueue_mask(&vsock->vhost_dev, vdev, i, false);
 117     }
 118
 119     return;
 120
 121 err_dev_start:
 122     vhost_dev_stop(&vsock->vhost_dev, vdev);
 123 err_guest_notifiers:
 124     k->set_guest_notifiers(qbus->parent, vsock->vhost_dev.nvqs, false);
 125 err_host_notifiers:
 126     vhost_dev_disable_notifiers(&vsock->vhost_dev, vdev);
 127 }
 128
 129 static void vhost_vsock_stop(VirtIODevice *vdev)
 130 {
 131     VHostVSock *vsock = VHOST_VSOCK(vdev);
 132     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
 133     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
 134     int ret;
 135
 136     if (!k->set_guest_notifiers) {
 137         return;
 138     }
 139
 140     ret = vhost_vsock_set_running(vsock, 0);
 141     if (ret < 0) {
 142         error_report("vhost vsock set running failed: %d", ret);
 143         return;
 144     }
 145
 146     vhost_dev_stop(&vsock->vhost_dev, vdev);
 147
 148     ret = k->set_guest_notifiers(qbus->parent, vsock->vhost_dev.nvqs, false);
 149     if (ret < 0) {
 150         error_report("vhost guest notifier cleanup failed: %d", ret);
 151         return;
 152     }
 153
 154     vhost_dev_disable_notifiers(&vsock->vhost_dev, vdev);
 155 }
 156
 157 static void vhost_vsock_set_status(VirtIODevice *vdev, uint8_t status)
 158 {
 159     VHostVSock *vsock = VHOST_VSOCK(vdev);
 160     bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
 161
 162     if (!vdev->vm_running) {
 163         should_start = false;
 164     }
 165
 166     if (vsock->vhost_dev.started == should_start) {
 167         return;
 168     }
 169
 170     if (should_start) {
 171         vhost_vsock_start(vdev);
 172     } else {
 173         vhost_vsock_stop(vdev);
 174     }
 175 }
 176
 177 static uint64_t vhost_vsock_get_features(VirtIODevice *vdev,
 178                                          uint64_t requested_features,
 179                                          Error **errp)
 180 {
 181     /* No feature bits used yet */
 182     return requested_features;
 183 }
 184
 185 static void vhost_vsock_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 186 {
 187     /* Do nothing */
 188 }
 189
 190 static void vhost_vsock_guest_notifier_mask(VirtIODevice *vdev, int idx,
 191                                             bool mask)
 192 {
 193     VHostVSock *vsock = VHOST_VSOCK(vdev);
 194
 195     vhost_virtqueue_mask(&vsock->vhost_dev, vdev, idx, mask);
 196 }
 197
 198 static bool vhost_vsock_guest_notifier_pending(VirtIODevice *vdev, int idx)
 199 {
 200     VHostVSock *vsock = VHOST_VSOCK(vdev);
 201
 202     return vhost_virtqueue_pending(&vsock->vhost_dev, idx);
 203 }
 204
 205 static void vhost_vsock_send_transport_reset(VHostVSock *vsock)
 206 {
 207     VirtQueueElement *elem;
 208     VirtQueue *vq = vsock->event_vq;
 209     struct virtio_vsock_event event = {
 210         .id = cpu_to_le32(VIRTIO_VSOCK_EVENT_TRANSPORT_RESET),
 211     };
 212
 213     elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
 214     if (!elem) {
 215         error_report("vhost-vsock missed transport reset event");
 216         return;
 217     }
 218
 219     if (elem->out_num) {
 220         error_report("invalid vhost-vsock event virtqueue element with "
 221                      "out buffers");
 222         goto out;
 223     }
 224
 225     if (iov_from_buf(elem->in_sg, elem->in_num, 0,
 226                      &event, sizeof(event)) != sizeof(event)) {
 227         error_report("vhost-vsock event virtqueue element is too short");
 228         goto out;
 229     }
 230
 231     virtqueue_push(vq, elem, sizeof(event));
 232     virtio_notify(VIRTIO_DEVICE(vsock), vq);
 233
 234 out:
 235     g_free(elem);
 236 }
 237
 238 static void vhost_vsock_post_load_timer_cleanup(VHostVSock *vsock)
 239 {
 240     if (!vsock->post_load_timer) {
 241         return;
 242     }
 243
 244     timer_del(vsock->post_load_timer);
 245     timer_free(vsock->post_load_timer);
 246     vsock->post_load_timer = NULL;
 247 }
 248
 249 static void vhost_vsock_post_load_timer_cb(void *opaque)
 250 {
 251     VHostVSock *vsock = opaque;
 252
 253     vhost_vsock_post_load_timer_cleanup(vsock);
 254     vhost_vsock_send_transport_reset(vsock);
 255 }
 256
 257 static int vhost_vsock_pre_save(void *opaque)
 258 {
 259     VHostVSock *vsock = opaque;
 260
 261     /* At this point, backend must be stopped, otherwise
 262      * it might keep writing to memory. */
 263     assert(!vsock->vhost_dev.started);
 264
 265     return 0;
 266 }
 267
 268 static int vhost_vsock_post_load(void *opaque, int version_id)
 269 {
 270     VHostVSock *vsock = opaque;
 271     VirtIODevice *vdev = VIRTIO_DEVICE(vsock);
 272
 273     if (virtio_queue_get_addr(vdev, 2)) {
 274         /* Defer transport reset event to a vm clock timer so that virtqueue
 275          * changes happen after migration has completed.
 276          */
 277         assert(!vsock->post_load_timer);
 278         vsock->post_load_timer =
 279             timer_new_ns(QEMU_CLOCK_VIRTUAL,
 280                          vhost_vsock_post_load_timer_cb,
 281                          vsock);
 282         timer_mod(vsock->post_load_timer, 1);
 283     }
 284     return 0;
 285 }
 286
 287 static const VMStateDescription vmstate_virtio_vhost_vsock = {
 288     .name = "virtio-vhost_vsock",
 289     .minimum_version_id = VHOST_VSOCK_SAVEVM_VERSION,
 290     .version_id = VHOST_VSOCK_SAVEVM_VERSION,
 291     .fields = (VMStateField[]) {
 292         VMSTATE_VIRTIO_DEVICE,
 293         VMSTATE_END_OF_LIST()
 294     },
 295     .pre_save = vhost_vsock_pre_save,
 296     .post_load = vhost_vsock_post_load,
 297 };
 298
 299 static void vhost_vsock_device_realize(DeviceState *dev, Error **errp)
 300 {
 301     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 302     VHostVSock *vsock = VHOST_VSOCK(dev);
 303     int vhostfd;
 304     int ret;
 305
 306     /* Refuse to use reserved CID numbers */
 307     if (vsock->conf.guest_cid <= 2) {
 308         error_setg(errp, "guest-cid property must be greater than 2");
 309         return;
 310     }
 311
 312     if (vsock->conf.guest_cid > UINT32_MAX) {
 313         error_setg(errp, "guest-cid property must be a 32-bit number");
 314         return;
 315     }
 316
 317     if (vsock->conf.vhostfd) {
 318         vhostfd = monitor_fd_param(cur_mon, vsock->conf.vhostfd, errp);
 319         if (vhostfd == -1) {
 320             error_prepend(errp, "vhost-vsock: unable to parse vhostfd: ");
 321             return;
 322         }
 323     } else {
 324         vhostfd = open("/dev/vhost-vsock", O_RDWR);
 325         if (vhostfd < 0) {
 326             error_setg_errno(errp, -errno,
 327                              "vhost-vsock: failed to open vhost device");
 328             return;
 329         }
 330     }
 331
 332     virtio_init(vdev, "vhost-vsock", VIRTIO_ID_VSOCK,
 333                 sizeof(struct virtio_vsock_config));
 334
 335     /* Receive and transmit queues belong to vhost */
 336     virtio_add_queue(vdev, VHOST_VSOCK_QUEUE_SIZE, vhost_vsock_handle_output);
 337     virtio_add_queue(vdev, VHOST_VSOCK_QUEUE_SIZE, vhost_vsock_handle_output);
 338
 339     /* The event queue belongs to QEMU */
 340     vsock->event_vq = virtio_add_queue(vdev, VHOST_VSOCK_QUEUE_SIZE,
 341                                        vhost_vsock_handle_output);
 342
 343     vsock->vhost_dev.nvqs = ARRAY_SIZE(vsock->vhost_vqs);
 344     vsock->vhost_dev.vqs = vsock->vhost_vqs;
 345     ret = vhost_dev_init(&vsock->vhost_dev, (void *)(uintptr_t)vhostfd,
 346                          VHOST_BACKEND_TYPE_KERNEL, 0);
 347     if (ret < 0) {
 348         error_setg_errno(errp, -ret, "vhost-vsock: vhost_dev_init failed");
 349         goto err_virtio;
 350     }
 351
 352     ret = vhost_vsock_set_guest_cid(vsock);
 353     if (ret < 0) {
 354         error_setg_errno(errp, -ret, "vhost-vsock: unable to set guest cid");
 355         goto err_vhost_dev;
 356     }
 357
 358     vsock->post_load_timer = NULL;
 359     return;
 360
 361 err_vhost_dev:
 362     vhost_dev_cleanup(&vsock->vhost_dev);
 363 err_virtio:
 364     virtio_cleanup(vdev);
 365     close(vhostfd);
 366     return;
 367 }
 368
 369 static void vhost_vsock_device_unrealize(DeviceState *dev, Error **errp)
 370 {
 371     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 372     VHostVSock *vsock = VHOST_VSOCK(dev);
 373
 374     vhost_vsock_post_load_timer_cleanup(vsock);
 375
 376     /* This will stop vhost backend if appropriate. */
 377     vhost_vsock_set_status(vdev, 0);
 378
 379     vhost_dev_cleanup(&vsock->vhost_dev);
 380     virtio_cleanup(vdev);
 381 }
 382
 383 static Property vhost_vsock_properties[] = {
 384     DEFINE_PROP_UINT64("guest-cid", VHostVSock, conf.guest_cid, 0),
 385     DEFINE_PROP_STRING("vhostfd", VHostVSock, conf.vhostfd),
 386     DEFINE_PROP_END_OF_LIST(),
 387 };
 388
 389 static void vhost_vsock_class_init(ObjectClass *klass, void *data)
 390 {
 391     DeviceClass *dc = DEVICE_CLASS(klass);
 392     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 393
 394     dc->props = vhost_vsock_properties;
 395     dc->vmsd = &vmstate_virtio_vhost_vsock;
 396     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 397     vdc->realize = vhost_vsock_device_realize;
 398     vdc->unrealize = vhost_vsock_device_unrealize;
 399     vdc->get_features = vhost_vsock_get_features;
 400     vdc->get_config = vhost_vsock_get_config;
 401     vdc->set_status = vhost_vsock_set_status;
 402     vdc->guest_notifier_mask = vhost_vsock_guest_notifier_mask;
 403     vdc->guest_notifier_pending = vhost_vsock_guest_notifier_pending;
 404 }
 405
 406 static const TypeInfo vhost_vsock_info = {
 407     .name = TYPE_VHOST_VSOCK,
 408     .parent = TYPE_VIRTIO_DEVICE,
 409     .instance_size = sizeof(VHostVSock),
 410     .class_init = vhost_vsock_class_init,
 411 };
 412
 413 static void vhost_vsock_register_types(void)
 414 {
 415     type_register_static(&vhost_vsock_info);
 416 }
 417
 418 type_init(vhost_vsock_register_types)