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
  36     VHOST_INVALID_FEATURE_BIT
  37 };
  38
  39 static void vuf_get_config(VirtIODevice *vdev, uint8_t *config)
  40 {
  41     VHostUserFS *fs = VHOST_USER_FS(vdev);
  42     struct virtio_fs_config fscfg = {};
  43
  44     memcpy((char *)fscfg.tag, fs->conf.tag,
  45            MIN(strlen(fs->conf.tag) + 1, sizeof(fscfg.tag)));
  46
  47     virtio_stl_p(vdev, &fscfg.num_request_queues, fs->conf.num_request_queues);
  48
  49     memcpy(config, &fscfg, sizeof(fscfg));
  50 }
  51
  52 static void vuf_start(VirtIODevice *vdev)
  53 {
  54     VHostUserFS *fs = VHOST_USER_FS(vdev);
  55     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
  56     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
  57     int ret;
  58     int i;
  59
  60     if (!k->set_guest_notifiers) {
  61         error_report("binding does not support guest notifiers");
  62         return;
  63     }
  64
  65     ret = vhost_dev_enable_notifiers(&fs->vhost_dev, vdev);
  66     if (ret < 0) {
  67         error_report("Error enabling host notifiers: %d", -ret);
  68         return;
  69     }
  70
  71     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, true);
  72     if (ret < 0) {
  73         error_report("Error binding guest notifier: %d", -ret);
  74         goto err_host_notifiers;
  75     }
  76
  77     fs->vhost_dev.acked_features = vdev->guest_features;
  78     ret = vhost_dev_start(&fs->vhost_dev, vdev);
  79     if (ret < 0) {
  80         error_report("Error starting vhost: %d", -ret);
  81         goto err_guest_notifiers;
  82     }
  83
  84     /*
  85      * guest_notifier_mask/pending not used yet, so just unmask
  86      * everything here.  virtio-pci will do the right thing by
  87      * enabling/disabling irqfd.
  88      */
  89     for (i = 0; i < fs->vhost_dev.nvqs; i++) {
  90         vhost_virtqueue_mask(&fs->vhost_dev, vdev, i, false);
  91     }
  92
  93     return;
  94
  95 err_guest_notifiers:
  96     k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
  97 err_host_notifiers:
  98     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
  99 }
 100
 101 static void vuf_stop(VirtIODevice *vdev)
 102 {
 103     VHostUserFS *fs = VHOST_USER_FS(vdev);
 104     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
 105     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
 106     int ret;
 107
 108     if (!k->set_guest_notifiers) {
 109         return;
 110     }
 111
 112     vhost_dev_stop(&fs->vhost_dev, vdev);
 113
 114     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
 115     if (ret < 0) {
 116         error_report("vhost guest notifier cleanup failed: %d", ret);
 117         return;
 118     }
 119
 120     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
 121 }
 122
 123 static void vuf_set_status(VirtIODevice *vdev, uint8_t status)
 124 {
 125     VHostUserFS *fs = VHOST_USER_FS(vdev);
 126     bool should_start = virtio_device_started(vdev, status);
 127
 128     if (vhost_dev_is_started(&fs->vhost_dev) == should_start) {
 129         return;
 130     }
 131
 132     if (should_start) {
 133         vuf_start(vdev);
 134     } else {
 135         vuf_stop(vdev);
 136     }
 137 }
 138
 139 static uint64_t vuf_get_features(VirtIODevice *vdev,
 140                                  uint64_t features,
 141                                  Error **errp)
 142 {
 143     VHostUserFS *fs = VHOST_USER_FS(vdev);
 144
 145     return vhost_get_features(&fs->vhost_dev, user_feature_bits, features);
 146 }
 147
 148 static void vuf_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 149 {
 150     /*
 151      * Not normally called; it's the daemon that handles the queue;
 152      * however virtio's cleanup path can call this.
 153      */
 154 }
 155
 156 static void vuf_guest_notifier_mask(VirtIODevice *vdev, int idx,
 157                                             bool mask)
 158 {
 159     VHostUserFS *fs = VHOST_USER_FS(vdev);
 160
 161     vhost_virtqueue_mask(&fs->vhost_dev, vdev, idx, mask);
 162 }
 163
 164 static bool vuf_guest_notifier_pending(VirtIODevice *vdev, int idx)
 165 {
 166     VHostUserFS *fs = VHOST_USER_FS(vdev);
 167
 168     return vhost_virtqueue_pending(&fs->vhost_dev, idx);
 169 }
 170
 171 static void vuf_device_realize(DeviceState *dev, Error **errp)
 172 {
 173     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 174     VHostUserFS *fs = VHOST_USER_FS(dev);
 175     unsigned int i;
 176     size_t len;
 177     int ret;
 178
 179     if (!fs->conf.chardev.chr) {
 180         error_setg(errp, "missing chardev");
 181         return;
 182     }
 183
 184     if (!fs->conf.tag) {
 185         error_setg(errp, "missing tag property");
 186         return;
 187     }
 188     len = strlen(fs->conf.tag);
 189     if (len == 0) {
 190         error_setg(errp, "tag property cannot be empty");
 191         return;
 192     }
 193     if (len > sizeof_field(struct virtio_fs_config, tag)) {
 194         error_setg(errp, "tag property must be %zu bytes or less",
 195                    sizeof_field(struct virtio_fs_config, tag));
 196         return;
 197     }
 198
 199     if (fs->conf.num_request_queues == 0) {
 200         error_setg(errp, "num-request-queues property must be larger than 0");
 201         return;
 202     }
 203
 204     if (!is_power_of_2(fs->conf.queue_size)) {
 205         error_setg(errp, "queue-size property must be a power of 2");
 206         return;
 207     }
 208
 209     if (fs->conf.queue_size > VIRTQUEUE_MAX_SIZE) {
 210         error_setg(errp, "queue-size property must be %u or smaller",
 211                    VIRTQUEUE_MAX_SIZE);
 212         return;
 213     }
 214
 215     if (!vhost_user_init(&fs->vhost_user, &fs->conf.chardev, errp)) {
 216         return;
 217     }
 218
 219     virtio_init(vdev, VIRTIO_ID_FS, sizeof(struct virtio_fs_config));
 220
 221     /* Hiprio queue */
 222     fs->hiprio_vq = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
 223
 224     /* Request queues */
 225     fs->req_vqs = g_new(VirtQueue *, fs->conf.num_request_queues);
 226     for (i = 0; i < fs->conf.num_request_queues; i++) {
 227         fs->req_vqs[i] = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
 228     }
 229
 230     /* 1 high prio queue, plus the number configured */
 231     fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues;
 232     fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
 233     ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
 234                          VHOST_BACKEND_TYPE_USER, 0, errp);
 235     if (ret < 0) {
 236         goto err_virtio;
 237     }
 238
 239     return;
 240
 241 err_virtio:
 242     vhost_user_cleanup(&fs->vhost_user);
 243     virtio_delete_queue(fs->hiprio_vq);
 244     for (i = 0; i < fs->conf.num_request_queues; i++) {
 245         virtio_delete_queue(fs->req_vqs[i]);
 246     }
 247     g_free(fs->req_vqs);
 248     virtio_cleanup(vdev);
 249     g_free(fs->vhost_dev.vqs);
 250     return;
 251 }
 252
 253 static void vuf_device_unrealize(DeviceState *dev)
 254 {
 255     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 256     VHostUserFS *fs = VHOST_USER_FS(dev);
 257     int i;
 258
 259     /* This will stop vhost backend if appropriate. */
 260     vuf_set_status(vdev, 0);
 261
 262     vhost_dev_cleanup(&fs->vhost_dev);
 263
 264     vhost_user_cleanup(&fs->vhost_user);
 265
 266     virtio_delete_queue(fs->hiprio_vq);
 267     for (i = 0; i < fs->conf.num_request_queues; i++) {
 268         virtio_delete_queue(fs->req_vqs[i]);
 269     }
 270     g_free(fs->req_vqs);
 271     virtio_cleanup(vdev);
 272     g_free(fs->vhost_dev.vqs);
 273     fs->vhost_dev.vqs = NULL;
 274 }
 275
 276 static struct vhost_dev *vuf_get_vhost(VirtIODevice *vdev)
 277 {
 278     VHostUserFS *fs = VHOST_USER_FS(vdev);
 279     return &fs->vhost_dev;
 280 }
 281
 282 static const VMStateDescription vuf_vmstate = {
 283     .name = "vhost-user-fs",
 284     .unmigratable = 1,
 285 };
 286
 287 static Property vuf_properties[] = {
 288     DEFINE_PROP_CHR("chardev", VHostUserFS, conf.chardev),
 289     DEFINE_PROP_STRING("tag", VHostUserFS, conf.tag),
 290     DEFINE_PROP_UINT16("num-request-queues", VHostUserFS,
 291                        conf.num_request_queues, 1),
 292     DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
 293     DEFINE_PROP_END_OF_LIST(),
 294 };
 295
 296 static void vuf_instance_init(Object *obj)
 297 {
 298     VHostUserFS *fs = VHOST_USER_FS(obj);
 299
 300     device_add_bootindex_property(obj, &fs->bootindex, "bootindex",
 301                                   "/filesystem@0", DEVICE(obj));
 302 }
 303
 304 static void vuf_class_init(ObjectClass *klass, void *data)
 305 {
 306     DeviceClass *dc = DEVICE_CLASS(klass);
 307     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 308
 309     device_class_set_props(dc, vuf_properties);
 310     dc->vmsd = &vuf_vmstate;
 311     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 312     vdc->realize = vuf_device_realize;
 313     vdc->unrealize = vuf_device_unrealize;
 314     vdc->get_features = vuf_get_features;
 315     vdc->get_config = vuf_get_config;
 316     vdc->set_status = vuf_set_status;
 317     vdc->guest_notifier_mask = vuf_guest_notifier_mask;
 318     vdc->guest_notifier_pending = vuf_guest_notifier_pending;
 319     vdc->get_vhost = vuf_get_vhost;
 320 }
 321
 322 static const TypeInfo vuf_info = {
 323     .name = TYPE_VHOST_USER_FS,
 324     .parent = TYPE_VIRTIO_DEVICE,
 325     .instance_size = sizeof(VHostUserFS),
 326     .instance_init = vuf_instance_init,
 327     .class_init = vuf_class_init,
 328 };
 329
 330 static void vuf_register_types(void)
 331 {
 332     type_register_static(&vuf_info);
 333 }
 334
 335 type_init(vuf_register_types)