hw/virtio/vhost-user-fs.c

   1 /*
   2  * Vhost-user filesystem virtio device
   3  *
   4  * Copyright 2018-2019 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_fs.h"
  17 #include "qapi/error.h"
  18 #include "hw/qdev-properties.h"
  19 #include "hw/qdev-properties-system.h"
  20 #include "hw/virtio/virtio-bus.h"
  21 #include "hw/virtio/virtio-access.h"
  22 #include "qemu/error-report.h"
  23 #include "hw/virtio/vhost.h"
  24 #include "hw/virtio/vhost-user-fs.h"
  25 #include "monitor/monitor.h"
  26 #include "sysemu/sysemu.h"
  27
  28 static const int user_feature_bits[] = {
  29     VIRTIO_F_VERSION_1,
  30     VIRTIO_RING_F_INDIRECT_DESC,
  31     VIRTIO_RING_F_EVENT_IDX,
  32     VIRTIO_F_NOTIFY_ON_EMPTY,
  33     VIRTIO_F_RING_PACKED,
  34     VIRTIO_F_IOMMU_PLATFORM,
  35     VIRTIO_F_RING_RESET,
  36
  37     VHOST_INVALID_FEATURE_BIT
  38 };
  39
  40 static void vuf_get_config(VirtIODevice *vdev, uint8_t *config)
  41 {
  42     VHostUserFS *fs = VHOST_USER_FS(vdev);
  43     struct virtio_fs_config fscfg = {};
  44
  45     memcpy((char *)fscfg.tag, fs->conf.tag,
  46            MIN(strlen(fs->conf.tag) + 1, sizeof(fscfg.tag)));
  47
  48     virtio_stl_p(vdev, &fscfg.num_request_queues, fs->conf.num_request_queues);
  49
  50     memcpy(config, &fscfg, sizeof(fscfg));
  51 }
  52
  53 static void vuf_start(VirtIODevice *vdev)
  54 {
  55     VHostUserFS *fs = VHOST_USER_FS(vdev);
  56     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
  57     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
  58     int ret;
  59     int i;
  60
  61     if (!k->set_guest_notifiers) {
  62         error_report("binding does not support guest notifiers");
  63         return;
  64     }
  65
  66     ret = vhost_dev_enable_notifiers(&fs->vhost_dev, vdev);
  67     if (ret < 0) {
  68         error_report("Error enabling host notifiers: %d", -ret);
  69         return;
  70     }
  71
  72     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, true);
  73     if (ret < 0) {
  74         error_report("Error binding guest notifier: %d", -ret);
  75         goto err_host_notifiers;
  76     }
  77
  78     fs->vhost_dev.acked_features = vdev->guest_features;
  79     ret = vhost_dev_start(&fs->vhost_dev, vdev, true);
  80     if (ret < 0) {
  81         error_report("Error starting vhost: %d", -ret);
  82         goto err_guest_notifiers;
  83     }
  84
  85     /*
  86      * guest_notifier_mask/pending not used yet, so just unmask
  87      * everything here.  virtio-pci will do the right thing by
  88      * enabling/disabling irqfd.
  89      */
  90     for (i = 0; i < fs->vhost_dev.nvqs; i++) {
  91         vhost_virtqueue_mask(&fs->vhost_dev, vdev, i, false);
  92     }
  93
  94     return;
  95
  96 err_guest_notifiers:
  97     k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
  98 err_host_notifiers:
  99     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
 100 }
 101
 102 static void vuf_stop(VirtIODevice *vdev)
 103 {
 104     VHostUserFS *fs = VHOST_USER_FS(vdev);
 105     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
 106     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
 107     int ret;
 108
 109     if (!k->set_guest_notifiers) {
 110         return;
 111     }
 112
 113     vhost_dev_stop(&fs->vhost_dev, vdev, true);
 114
 115     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
 116     if (ret < 0) {
 117         error_report("vhost guest notifier cleanup failed: %d", ret);
 118         return;
 119     }
 120
 121     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
 122 }
 123
 124 static void vuf_set_status(VirtIODevice *vdev, uint8_t status)
 125 {
 126     VHostUserFS *fs = VHOST_USER_FS(vdev);
 127     bool should_start = virtio_device_should_start(vdev, status);
 128
 129     if (vhost_dev_is_started(&fs->vhost_dev) == should_start) {
 130         return;
 131     }
 132
 133     if (should_start) {
 134         vuf_start(vdev);
 135     } else {
 136         vuf_stop(vdev);
 137     }
 138 }
 139
 140 static uint64_t vuf_get_features(VirtIODevice *vdev,
 141                                  uint64_t features,
 142                                  Error **errp)
 143 {
 144     VHostUserFS *fs = VHOST_USER_FS(vdev);
 145
 146     return vhost_get_features(&fs->vhost_dev, user_feature_bits, features);
 147 }
 148
 149 static void vuf_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 150 {
 151     /*
 152      * Not normally called; it's the daemon that handles the queue;
 153      * however virtio's cleanup path can call this.
 154      */
 155 }
 156
 157 static void vuf_guest_notifier_mask(VirtIODevice *vdev, int idx,
 158                                             bool mask)
 159 {
 160     VHostUserFS *fs = VHOST_USER_FS(vdev);
 161
 162     /*
 163      * Add the check for configure interrupt, Use VIRTIO_CONFIG_IRQ_IDX -1
 164      * as the macro of configure interrupt's IDX, If this driver does not
 165      * support, the function will return
 166      */
 167
 168     if (idx == VIRTIO_CONFIG_IRQ_IDX) {
 169         return;
 170     }
 171     vhost_virtqueue_mask(&fs->vhost_dev, vdev, idx, mask);
 172 }
 173
 174 static bool vuf_guest_notifier_pending(VirtIODevice *vdev, int idx)
 175 {
 176     VHostUserFS *fs = VHOST_USER_FS(vdev);
 177
 178     /*
 179      * Add the check for configure interrupt, Use VIRTIO_CONFIG_IRQ_IDX -1
 180      * as the macro of configure interrupt's IDX, If this driver does not
 181      * support, the function will return
 182      */
 183
 184     if (idx == VIRTIO_CONFIG_IRQ_IDX) {
 185         return false;
 186     }
 187     return vhost_virtqueue_pending(&fs->vhost_dev, idx);
 188 }
 189
 190 static void vuf_device_realize(DeviceState *dev, Error **errp)
 191 {
 192     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 193     VHostUserFS *fs = VHOST_USER_FS(dev);
 194     unsigned int i;
 195     size_t len;
 196     int ret;
 197
 198     if (!fs->conf.chardev.chr) {
 199         error_setg(errp, "missing chardev");
 200         return;
 201     }
 202
 203     if (!fs->conf.tag) {
 204         error_setg(errp, "missing tag property");
 205         return;
 206     }
 207     len = strlen(fs->conf.tag);
 208     if (len == 0) {
 209         error_setg(errp, "tag property cannot be empty");
 210         return;
 211     }
 212     if (len > sizeof_field(struct virtio_fs_config, tag)) {
 213         error_setg(errp, "tag property must be %zu bytes or less",
 214                    sizeof_field(struct virtio_fs_config, tag));
 215         return;
 216     }
 217
 218     if (fs->conf.num_request_queues == 0) {
 219         error_setg(errp, "num-request-queues property must be larger than 0");
 220         return;
 221     }
 222
 223     if (!is_power_of_2(fs->conf.queue_size)) {
 224         error_setg(errp, "queue-size property must be a power of 2");
 225         return;
 226     }
 227
 228     if (fs->conf.queue_size > VIRTQUEUE_MAX_SIZE) {
 229         error_setg(errp, "queue-size property must be %u or smaller",
 230                    VIRTQUEUE_MAX_SIZE);
 231         return;
 232     }
 233
 234     if (!vhost_user_init(&fs->vhost_user, &fs->conf.chardev, errp)) {
 235         return;
 236     }
 237
 238     virtio_init(vdev, VIRTIO_ID_FS, sizeof(struct virtio_fs_config));
 239
 240     /* Hiprio queue */
 241     fs->hiprio_vq = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
 242
 243     /* Request queues */
 244     fs->req_vqs = g_new(VirtQueue *, fs->conf.num_request_queues);
 245     for (i = 0; i < fs->conf.num_request_queues; i++) {
 246         fs->req_vqs[i] = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
 247     }
 248
 249     /* 1 high prio queue, plus the number configured */
 250     fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues;
 251     fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
 252     ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
 253                          VHOST_BACKEND_TYPE_USER, 0, errp);
 254     if (ret < 0) {
 255         goto err_virtio;
 256     }
 257
 258     return;
 259
 260 err_virtio:
 261     vhost_user_cleanup(&fs->vhost_user);
 262     virtio_delete_queue(fs->hiprio_vq);
 263     for (i = 0; i < fs->conf.num_request_queues; i++) {
 264         virtio_delete_queue(fs->req_vqs[i]);
 265     }
 266     g_free(fs->req_vqs);
 267     virtio_cleanup(vdev);
 268     g_free(fs->vhost_dev.vqs);
 269     return;
 270 }
 271
 272 static void vuf_device_unrealize(DeviceState *dev)
 273 {
 274     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 275     VHostUserFS *fs = VHOST_USER_FS(dev);
 276     struct vhost_virtqueue *vhost_vqs = fs->vhost_dev.vqs;
 277     int i;
 278
 279     /* This will stop vhost backend if appropriate. */
 280     vuf_set_status(vdev, 0);
 281
 282     vhost_dev_cleanup(&fs->vhost_dev);
 283
 284     vhost_user_cleanup(&fs->vhost_user);
 285
 286     virtio_delete_queue(fs->hiprio_vq);
 287     for (i = 0; i < fs->conf.num_request_queues; i++) {
 288         virtio_delete_queue(fs->req_vqs[i]);
 289     }
 290     g_free(fs->req_vqs);
 291     virtio_cleanup(vdev);
 292     g_free(vhost_vqs);
 293 }
 294
 295 static struct vhost_dev *vuf_get_vhost(VirtIODevice *vdev)
 296 {
 297     VHostUserFS *fs = VHOST_USER_FS(vdev);
 298     return &fs->vhost_dev;
 299 }
 300
 301 /**
 302  * Fetch the internal state from virtiofsd and save it to `f`.
 303  */
 304 static int vuf_save_state(QEMUFile *f, void *pv, size_t size,
 305                           const VMStateField *field, JSONWriter *vmdesc)
 306 {
 307     VirtIODevice *vdev = pv;
 308     VHostUserFS *fs = VHOST_USER_FS(vdev);
 309     Error *local_error = NULL;
 310     int ret;
 311
 312     ret = vhost_save_backend_state(&fs->vhost_dev, f, &local_error);
 313     if (ret < 0) {
 314         error_reportf_err(local_error,
 315                           "Error saving back-end state of %s device %s "
 316                           "(tag: \"%s\"): ",
 317                           vdev->name, vdev->parent_obj.canonical_path,
 318                           fs->conf.tag ?: "<none>");
 319         return ret;
 320     }
 321
 322     return 0;
 323 }
 324
 325 /**
 326  * Load virtiofsd's internal state from `f` and send it over to virtiofsd.
 327  */
 328 static int vuf_load_state(QEMUFile *f, void *pv, size_t size,
 329                           const VMStateField *field)
 330 {
 331     VirtIODevice *vdev = pv;
 332     VHostUserFS *fs = VHOST_USER_FS(vdev);
 333     Error *local_error = NULL;
 334     int ret;
 335
 336     ret = vhost_load_backend_state(&fs->vhost_dev, f, &local_error);
 337     if (ret < 0) {
 338         error_reportf_err(local_error,
 339                           "Error loading back-end state of %s device %s "
 340                           "(tag: \"%s\"): ",
 341                           vdev->name, vdev->parent_obj.canonical_path,
 342                           fs->conf.tag ?: "<none>");
 343         return ret;
 344     }
 345
 346     return 0;
 347 }
 348
 349 static bool vuf_is_internal_migration(void *opaque)
 350 {
 351     /* TODO: Return false when an external migration is requested */
 352     return true;
 353 }
 354
 355 static int vuf_check_migration_support(void *opaque)
 356 {
 357     VirtIODevice *vdev = opaque;
 358     VHostUserFS *fs = VHOST_USER_FS(vdev);
 359
 360     if (!vhost_supports_device_state(&fs->vhost_dev)) {
 361         error_report("Back-end of %s device %s (tag: \"%s\") does not support "
 362                      "migration through qemu",
 363                      vdev->name, vdev->parent_obj.canonical_path,
 364                      fs->conf.tag ?: "<none>");
 365         return -ENOTSUP;
 366     }
 367
 368     return 0;
 369 }
 370
 371 static const VMStateDescription vuf_backend_vmstate;
 372
 373 static const VMStateDescription vuf_vmstate = {
 374     .name = "vhost-user-fs",
 375     .version_id = 0,
 376     .fields = (const VMStateField[]) {
 377         VMSTATE_VIRTIO_DEVICE,
 378         VMSTATE_END_OF_LIST()
 379     },
 380     .subsections = (const VMStateDescription * const []) {
 381         &vuf_backend_vmstate,
 382         NULL,
 383     }
 384 };
 385
 386 static const VMStateDescription vuf_backend_vmstate = {
 387     .name = "vhost-user-fs-backend",
 388     .version_id = 0,
 389     .needed = vuf_is_internal_migration,
 390     .pre_load = vuf_check_migration_support,
 391     .pre_save = vuf_check_migration_support,
 392     .fields = (const VMStateField[]) {
 393         {
 394             .name = "back-end",
 395             .info = &(const VMStateInfo) {
 396                 .name = "virtio-fs back-end state",
 397                 .get = vuf_load_state,
 398                 .put = vuf_save_state,
 399             },
 400         },
 401         VMSTATE_END_OF_LIST()
 402     },
 403 };
 404
 405 static Property vuf_properties[] = {
 406     DEFINE_PROP_CHR("chardev", VHostUserFS, conf.chardev),
 407     DEFINE_PROP_STRING("tag", VHostUserFS, conf.tag),
 408     DEFINE_PROP_UINT16("num-request-queues", VHostUserFS,
 409                        conf.num_request_queues, 1),
 410     DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
 411     DEFINE_PROP_END_OF_LIST(),
 412 };
 413
 414 static void vuf_instance_init(Object *obj)
 415 {
 416     VHostUserFS *fs = VHOST_USER_FS(obj);
 417
 418     device_add_bootindex_property(obj, &fs->bootindex, "bootindex",
 419                                   "/filesystem@0", DEVICE(obj));
 420 }
 421
 422 static void vuf_class_init(ObjectClass *klass, void *data)
 423 {
 424     DeviceClass *dc = DEVICE_CLASS(klass);
 425     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 426
 427     device_class_set_props(dc, vuf_properties);
 428     dc->vmsd = &vuf_vmstate;
 429     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 430     vdc->realize = vuf_device_realize;
 431     vdc->unrealize = vuf_device_unrealize;
 432     vdc->get_features = vuf_get_features;
 433     vdc->get_config = vuf_get_config;
 434     vdc->set_status = vuf_set_status;
 435     vdc->guest_notifier_mask = vuf_guest_notifier_mask;
 436     vdc->guest_notifier_pending = vuf_guest_notifier_pending;
 437     vdc->get_vhost = vuf_get_vhost;
 438 }
 439
 440 static const TypeInfo vuf_info = {
 441     .name = TYPE_VHOST_USER_FS,
 442     .parent = TYPE_VIRTIO_DEVICE,
 443     .instance_size = sizeof(VHostUserFS),
 444     .instance_init = vuf_instance_init,
 445     .class_init = vuf_class_init,
 446 };
 447
 448 static void vuf_register_types(void)
 449 {
 450     type_register_static(&vuf_info);
 451 }
 452
 453 type_init(vuf_register_types)