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-user-fs.h"
  24 #include "monitor/monitor.h"
  25 #include "sysemu/sysemu.h"
  26
  27 static const int user_feature_bits[] = {
  28     VIRTIO_F_VERSION_1,
  29     VIRTIO_RING_F_INDIRECT_DESC,
  30     VIRTIO_RING_F_EVENT_IDX,
  31     VIRTIO_F_NOTIFY_ON_EMPTY,
  32     VIRTIO_F_RING_PACKED,
  33     VIRTIO_F_IOMMU_PLATFORM,
  34
  35     VHOST_INVALID_FEATURE_BIT
  36 };
  37
  38 static void vuf_get_config(VirtIODevice *vdev, uint8_t *config)
  39 {
  40     VHostUserFS *fs = VHOST_USER_FS(vdev);
  41     struct virtio_fs_config fscfg = {};
  42
  43     memcpy((char *)fscfg.tag, fs->conf.tag,
  44            MIN(strlen(fs->conf.tag) + 1, sizeof(fscfg.tag)));
  45
  46     virtio_stl_p(vdev, &fscfg.num_request_queues, fs->conf.num_request_queues);
  47
  48     memcpy(config, &fscfg, sizeof(fscfg));
  49 }
  50
  51 static void vuf_start(VirtIODevice *vdev)
  52 {
  53     VHostUserFS *fs = VHOST_USER_FS(vdev);
  54     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
  55     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
  56     int ret;
  57     int i;
  58
  59     if (!k->set_guest_notifiers) {
  60         error_report("binding does not support guest notifiers");
  61         return;
  62     }
  63
  64     ret = vhost_dev_enable_notifiers(&fs->vhost_dev, vdev);
  65     if (ret < 0) {
  66         error_report("Error enabling host notifiers: %d", -ret);
  67         return;
  68     }
  69
  70     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, true);
  71     if (ret < 0) {
  72         error_report("Error binding guest notifier: %d", -ret);
  73         goto err_host_notifiers;
  74     }
  75
  76     fs->vhost_dev.acked_features = vdev->guest_features;
  77     ret = vhost_dev_start(&fs->vhost_dev, vdev);
  78     if (ret < 0) {
  79         error_report("Error starting vhost: %d", -ret);
  80         goto err_guest_notifiers;
  81     }
  82
  83     /*
  84      * guest_notifier_mask/pending not used yet, so just unmask
  85      * everything here.  virtio-pci will do the right thing by
  86      * enabling/disabling irqfd.
  87      */
  88     for (i = 0; i < fs->vhost_dev.nvqs; i++) {
  89         vhost_virtqueue_mask(&fs->vhost_dev, vdev, i, false);
  90     }
  91
  92     return;
  93
  94 err_guest_notifiers:
  95     k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
  96 err_host_notifiers:
  97     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
  98 }
  99
 100 static void vuf_stop(VirtIODevice *vdev)
 101 {
 102     VHostUserFS *fs = VHOST_USER_FS(vdev);
 103     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
 104     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
 105     int ret;
 106
 107     if (!k->set_guest_notifiers) {
 108         return;
 109     }
 110
 111     vhost_dev_stop(&fs->vhost_dev, vdev);
 112
 113     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
 114     if (ret < 0) {
 115         error_report("vhost guest notifier cleanup failed: %d", ret);
 116         return;
 117     }
 118
 119     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
 120 }
 121
 122 static void vuf_set_status(VirtIODevice *vdev, uint8_t status)
 123 {
 124     VHostUserFS *fs = VHOST_USER_FS(vdev);
 125     bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
 126
 127     if (!vdev->vm_running) {
 128         should_start = false;
 129     }
 130
 131     if (fs->vhost_dev.started == should_start) {
 132         return;
 133     }
 134
 135     if (should_start) {
 136         vuf_start(vdev);
 137     } else {
 138         vuf_stop(vdev);
 139     }
 140 }
 141
 142 static uint64_t vuf_get_features(VirtIODevice *vdev,
 143                                  uint64_t features,
 144                                  Error **errp)
 145 {
 146     VHostUserFS *fs = VHOST_USER_FS(vdev);
 147
 148     return vhost_get_features(&fs->vhost_dev, user_feature_bits, features);
 149 }
 150
 151 static void vuf_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 152 {
 153     /*
 154      * Not normally called; it's the daemon that handles the queue;
 155      * however virtio's cleanup path can call this.
 156      */
 157 }
 158
 159 static void vuf_guest_notifier_mask(VirtIODevice *vdev, int idx,
 160                                             bool mask)
 161 {
 162     VHostUserFS *fs = VHOST_USER_FS(vdev);
 163
 164     vhost_virtqueue_mask(&fs->vhost_dev, vdev, idx, mask);
 165 }
 166
 167 static bool vuf_guest_notifier_pending(VirtIODevice *vdev, int idx)
 168 {
 169     VHostUserFS *fs = VHOST_USER_FS(vdev);
 170
 171     return vhost_virtqueue_pending(&fs->vhost_dev, idx);
 172 }
 173
 174 static void vuf_device_realize(DeviceState *dev, Error **errp)
 175 {
 176     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 177     VHostUserFS *fs = VHOST_USER_FS(dev);
 178     unsigned int i;
 179     size_t len;
 180     int ret;
 181
 182     if (!fs->conf.chardev.chr) {
 183         error_setg(errp, "missing chardev");
 184         return;
 185     }
 186
 187     if (!fs->conf.tag) {
 188         error_setg(errp, "missing tag property");
 189         return;
 190     }
 191     len = strlen(fs->conf.tag);
 192     if (len == 0) {
 193         error_setg(errp, "tag property cannot be empty");
 194         return;
 195     }
 196     if (len > sizeof_field(struct virtio_fs_config, tag)) {
 197         error_setg(errp, "tag property must be %zu bytes or less",
 198                    sizeof_field(struct virtio_fs_config, tag));
 199         return;
 200     }
 201
 202     if (fs->conf.num_request_queues == 0) {
 203         error_setg(errp, "num-request-queues property must be larger than 0");
 204         return;
 205     }
 206
 207     if (!is_power_of_2(fs->conf.queue_size)) {
 208         error_setg(errp, "queue-size property must be a power of 2");
 209         return;
 210     }
 211
 212     if (fs->conf.queue_size > VIRTQUEUE_MAX_SIZE) {
 213         error_setg(errp, "queue-size property must be %u or smaller",
 214                    VIRTQUEUE_MAX_SIZE);
 215         return;
 216     }
 217
 218     if (!vhost_user_init(&fs->vhost_user, &fs->conf.chardev, errp)) {
 219         return;
 220     }
 221
 222     virtio_init(vdev, "vhost-user-fs", VIRTIO_ID_FS,
 223                 sizeof(struct virtio_fs_config));
 224
 225     /* Hiprio queue */
 226     fs->hiprio_vq = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
 227
 228     /* Request queues */
 229     fs->req_vqs = g_new(VirtQueue *, fs->conf.num_request_queues);
 230     for (i = 0; i < fs->conf.num_request_queues; i++) {
 231         fs->req_vqs[i] = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
 232     }
 233
 234     /* 1 high prio queue, plus the number configured */
 235     fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues;
 236     fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
 237     ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
 238                          VHOST_BACKEND_TYPE_USER, 0, errp);
 239     if (ret < 0) {
 240         goto err_virtio;
 241     }
 242
 243     return;
 244
 245 err_virtio:
 246     vhost_user_cleanup(&fs->vhost_user);
 247     virtio_delete_queue(fs->hiprio_vq);
 248     for (i = 0; i < fs->conf.num_request_queues; i++) {
 249         virtio_delete_queue(fs->req_vqs[i]);
 250     }
 251     g_free(fs->req_vqs);
 252     virtio_cleanup(vdev);
 253     g_free(fs->vhost_dev.vqs);
 254     return;
 255 }
 256
 257 static void vuf_device_unrealize(DeviceState *dev)
 258 {
 259     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 260     VHostUserFS *fs = VHOST_USER_FS(dev);
 261     int i;
 262
 263     /* This will stop vhost backend if appropriate. */
 264     vuf_set_status(vdev, 0);
 265
 266     vhost_dev_cleanup(&fs->vhost_dev);
 267
 268     vhost_user_cleanup(&fs->vhost_user);
 269
 270     virtio_delete_queue(fs->hiprio_vq);
 271     for (i = 0; i < fs->conf.num_request_queues; i++) {
 272         virtio_delete_queue(fs->req_vqs[i]);
 273     }
 274     g_free(fs->req_vqs);
 275     virtio_cleanup(vdev);
 276     g_free(fs->vhost_dev.vqs);
 277     fs->vhost_dev.vqs = NULL;
 278 }
 279
 280 static const VMStateDescription vuf_vmstate = {
 281     .name = "vhost-user-fs",
 282     .unmigratable = 1,
 283 };
 284
 285 static Property vuf_properties[] = {
 286     DEFINE_PROP_CHR("chardev", VHostUserFS, conf.chardev),
 287     DEFINE_PROP_STRING("tag", VHostUserFS, conf.tag),
 288     DEFINE_PROP_UINT16("num-request-queues", VHostUserFS,
 289                        conf.num_request_queues, 1),
 290     DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
 291     DEFINE_PROP_END_OF_LIST(),
 292 };
 293
 294 static void vuf_instance_init(Object *obj)
 295 {
 296     VHostUserFS *fs = VHOST_USER_FS(obj);
 297
 298     device_add_bootindex_property(obj, &fs->bootindex, "bootindex",
 299                                   "/filesystem@0", DEVICE(obj));
 300 }
 301
 302 static void vuf_class_init(ObjectClass *klass, void *data)
 303 {
 304     DeviceClass *dc = DEVICE_CLASS(klass);
 305     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 306
 307     device_class_set_props(dc, vuf_properties);
 308     dc->vmsd = &vuf_vmstate;
 309     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 310     vdc->realize = vuf_device_realize;
 311     vdc->unrealize = vuf_device_unrealize;
 312     vdc->get_features = vuf_get_features;
 313     vdc->get_config = vuf_get_config;
 314     vdc->set_status = vuf_set_status;
 315     vdc->guest_notifier_mask = vuf_guest_notifier_mask;
 316     vdc->guest_notifier_pending = vuf_guest_notifier_pending;
 317 }
 318
 319 static const TypeInfo vuf_info = {
 320     .name = TYPE_VHOST_USER_FS,
 321     .parent = TYPE_VIRTIO_DEVICE,
 322     .instance_size = sizeof(VHostUserFS),
 323     .instance_init = vuf_instance_init,
 324     .class_init = vuf_class_init,
 325 };
 326
 327 static void vuf_register_types(void)
 328 {
 329     type_register_static(&vuf_info);
 330 }
 331
 332 type_init(vuf_register_types)