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);
  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);
 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     vhost_virtqueue_mask(&fs->vhost_dev, vdev, idx, mask);
 163 }
 164
 165 static bool vuf_guest_notifier_pending(VirtIODevice *vdev, int idx)
 166 {
 167     VHostUserFS *fs = VHOST_USER_FS(vdev);
 168
 169     return vhost_virtqueue_pending(&fs->vhost_dev, idx);
 170 }
 171
 172 static void vuf_device_realize(DeviceState *dev, Error **errp)
 173 {
 174     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 175     VHostUserFS *fs = VHOST_USER_FS(dev);
 176     unsigned int i;
 177     size_t len;
 178     int ret;
 179
 180     if (!fs->conf.chardev.chr) {
 181         error_setg(errp, "missing chardev");
 182         return;
 183     }
 184
 185     if (!fs->conf.tag) {
 186         error_setg(errp, "missing tag property");
 187         return;
 188     }
 189     len = strlen(fs->conf.tag);
 190     if (len == 0) {
 191         error_setg(errp, "tag property cannot be empty");
 192         return;
 193     }
 194     if (len > sizeof_field(struct virtio_fs_config, tag)) {
 195         error_setg(errp, "tag property must be %zu bytes or less",
 196                    sizeof_field(struct virtio_fs_config, tag));
 197         return;
 198     }
 199
 200     if (fs->conf.num_request_queues == 0) {
 201         error_setg(errp, "num-request-queues property must be larger than 0");
 202         return;
 203     }
 204
 205     if (!is_power_of_2(fs->conf.queue_size)) {
 206         error_setg(errp, "queue-size property must be a power of 2");
 207         return;
 208     }
 209
 210     if (fs->conf.queue_size > VIRTQUEUE_MAX_SIZE) {
 211         error_setg(errp, "queue-size property must be %u or smaller",
 212                    VIRTQUEUE_MAX_SIZE);
 213         return;
 214     }
 215
 216     if (!vhost_user_init(&fs->vhost_user, &fs->conf.chardev, errp)) {
 217         return;
 218     }
 219
 220     virtio_init(vdev, VIRTIO_ID_FS, sizeof(struct virtio_fs_config));
 221
 222     /* Hiprio queue */
 223     fs->hiprio_vq = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
 224
 225     /* Request queues */
 226     fs->req_vqs = g_new(VirtQueue *, fs->conf.num_request_queues);
 227     for (i = 0; i < fs->conf.num_request_queues; i++) {
 228         fs->req_vqs[i] = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
 229     }
 230
 231     /* 1 high prio queue, plus the number configured */
 232     fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues;
 233     fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
 234     ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
 235                          VHOST_BACKEND_TYPE_USER, 0, errp);
 236     if (ret < 0) {
 237         goto err_virtio;
 238     }
 239
 240     return;
 241
 242 err_virtio:
 243     vhost_user_cleanup(&fs->vhost_user);
 244     virtio_delete_queue(fs->hiprio_vq);
 245     for (i = 0; i < fs->conf.num_request_queues; i++) {
 246         virtio_delete_queue(fs->req_vqs[i]);
 247     }
 248     g_free(fs->req_vqs);
 249     virtio_cleanup(vdev);
 250     g_free(fs->vhost_dev.vqs);
 251     return;
 252 }
 253
 254 static void vuf_device_unrealize(DeviceState *dev)
 255 {
 256     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 257     VHostUserFS *fs = VHOST_USER_FS(dev);
 258     int i;
 259
 260     /* This will stop vhost backend if appropriate. */
 261     vuf_set_status(vdev, 0);
 262
 263     vhost_dev_cleanup(&fs->vhost_dev);
 264
 265     vhost_user_cleanup(&fs->vhost_user);
 266
 267     virtio_delete_queue(fs->hiprio_vq);
 268     for (i = 0; i < fs->conf.num_request_queues; i++) {
 269         virtio_delete_queue(fs->req_vqs[i]);
 270     }
 271     g_free(fs->req_vqs);
 272     virtio_cleanup(vdev);
 273     g_free(fs->vhost_dev.vqs);
 274     fs->vhost_dev.vqs = NULL;
 275 }
 276
 277 static struct vhost_dev *vuf_get_vhost(VirtIODevice *vdev)
 278 {
 279     VHostUserFS *fs = VHOST_USER_FS(vdev);
 280     return &fs->vhost_dev;
 281 }
 282
 283 static const VMStateDescription vuf_vmstate = {
 284     .name = "vhost-user-fs",
 285     .unmigratable = 1,
 286 };
 287
 288 static Property vuf_properties[] = {
 289     DEFINE_PROP_CHR("chardev", VHostUserFS, conf.chardev),
 290     DEFINE_PROP_STRING("tag", VHostUserFS, conf.tag),
 291     DEFINE_PROP_UINT16("num-request-queues", VHostUserFS,
 292                        conf.num_request_queues, 1),
 293     DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
 294     DEFINE_PROP_END_OF_LIST(),
 295 };
 296
 297 static void vuf_instance_init(Object *obj)
 298 {
 299     VHostUserFS *fs = VHOST_USER_FS(obj);
 300
 301     device_add_bootindex_property(obj, &fs->bootindex, "bootindex",
 302                                   "/filesystem@0", DEVICE(obj));
 303 }
 304
 305 static void vuf_class_init(ObjectClass *klass, void *data)
 306 {
 307     DeviceClass *dc = DEVICE_CLASS(klass);
 308     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 309
 310     device_class_set_props(dc, vuf_properties);
 311     dc->vmsd = &vuf_vmstate;
 312     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 313     vdc->realize = vuf_device_realize;
 314     vdc->unrealize = vuf_device_unrealize;
 315     vdc->get_features = vuf_get_features;
 316     vdc->get_config = vuf_get_config;
 317     vdc->set_status = vuf_set_status;
 318     vdc->guest_notifier_mask = vuf_guest_notifier_mask;
 319     vdc->guest_notifier_pending = vuf_guest_notifier_pending;
 320     vdc->get_vhost = vuf_get_vhost;
 321 }
 322
 323 static const TypeInfo vuf_info = {
 324     .name = TYPE_VHOST_USER_FS,
 325     .parent = TYPE_VIRTIO_DEVICE,
 326     .instance_size = sizeof(VHostUserFS),
 327     .instance_init = vuf_instance_init,
 328     .class_init = vuf_class_init,
 329 };
 330
 331 static void vuf_register_types(void)
 332 {
 333     type_register_static(&vuf_info);
 334 }
 335
 336 type_init(vuf_register_types)