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
  26 static void vuf_get_config(VirtIODevice *vdev, uint8_t *config)
  27 {
  28     VHostUserFS *fs = VHOST_USER_FS(vdev);
  29     struct virtio_fs_config fscfg = {};
  30
  31     memcpy((char *)fscfg.tag, fs->conf.tag,
  32            MIN(strlen(fs->conf.tag) + 1, sizeof(fscfg.tag)));
  33
  34     virtio_stl_p(vdev, &fscfg.num_request_queues, fs->conf.num_request_queues);
  35
  36     memcpy(config, &fscfg, sizeof(fscfg));
  37 }
  38
  39 static void vuf_start(VirtIODevice *vdev)
  40 {
  41     VHostUserFS *fs = VHOST_USER_FS(vdev);
  42     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
  43     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
  44     int ret;
  45     int i;
  46
  47     if (!k->set_guest_notifiers) {
  48         error_report("binding does not support guest notifiers");
  49         return;
  50     }
  51
  52     ret = vhost_dev_enable_notifiers(&fs->vhost_dev, vdev);
  53     if (ret < 0) {
  54         error_report("Error enabling host notifiers: %d", -ret);
  55         return;
  56     }
  57
  58     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, true);
  59     if (ret < 0) {
  60         error_report("Error binding guest notifier: %d", -ret);
  61         goto err_host_notifiers;
  62     }
  63
  64     fs->vhost_dev.acked_features = vdev->guest_features;
  65     ret = vhost_dev_start(&fs->vhost_dev, vdev);
  66     if (ret < 0) {
  67         error_report("Error starting vhost: %d", -ret);
  68         goto err_guest_notifiers;
  69     }
  70
  71     /*
  72      * guest_notifier_mask/pending not used yet, so just unmask
  73      * everything here.  virtio-pci will do the right thing by
  74      * enabling/disabling irqfd.
  75      */
  76     for (i = 0; i < fs->vhost_dev.nvqs; i++) {
  77         vhost_virtqueue_mask(&fs->vhost_dev, vdev, i, false);
  78     }
  79
  80     return;
  81
  82 err_guest_notifiers:
  83     k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
  84 err_host_notifiers:
  85     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
  86 }
  87
  88 static void vuf_stop(VirtIODevice *vdev)
  89 {
  90     VHostUserFS *fs = VHOST_USER_FS(vdev);
  91     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
  92     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
  93     int ret;
  94
  95     if (!k->set_guest_notifiers) {
  96         return;
  97     }
  98
  99     vhost_dev_stop(&fs->vhost_dev, vdev);
 100
 101     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
 102     if (ret < 0) {
 103         error_report("vhost guest notifier cleanup failed: %d", ret);
 104         return;
 105     }
 106
 107     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
 108 }
 109
 110 static void vuf_set_status(VirtIODevice *vdev, uint8_t status)
 111 {
 112     VHostUserFS *fs = VHOST_USER_FS(vdev);
 113     bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
 114
 115     if (!vdev->vm_running) {
 116         should_start = false;
 117     }
 118
 119     if (fs->vhost_dev.started == should_start) {
 120         return;
 121     }
 122
 123     if (should_start) {
 124         vuf_start(vdev);
 125     } else {
 126         vuf_stop(vdev);
 127     }
 128 }
 129
 130 static uint64_t vuf_get_features(VirtIODevice *vdev,
 131                                       uint64_t requested_features,
 132                                       Error **errp)
 133 {
 134     /* No feature bits used yet */
 135     return requested_features;
 136 }
 137
 138 static void vuf_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 139 {
 140     /*
 141      * Not normally called; it's the daemon that handles the queue;
 142      * however virtio's cleanup path can call this.
 143      */
 144 }
 145
 146 static void vuf_guest_notifier_mask(VirtIODevice *vdev, int idx,
 147                                             bool mask)
 148 {
 149     VHostUserFS *fs = VHOST_USER_FS(vdev);
 150
 151     vhost_virtqueue_mask(&fs->vhost_dev, vdev, idx, mask);
 152 }
 153
 154 static bool vuf_guest_notifier_pending(VirtIODevice *vdev, int idx)
 155 {
 156     VHostUserFS *fs = VHOST_USER_FS(vdev);
 157
 158     return vhost_virtqueue_pending(&fs->vhost_dev, idx);
 159 }
 160
 161 static void vuf_device_realize(DeviceState *dev, Error **errp)
 162 {
 163     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 164     VHostUserFS *fs = VHOST_USER_FS(dev);
 165     unsigned int i;
 166     size_t len;
 167     int ret;
 168
 169     if (!fs->conf.chardev.chr) {
 170         error_setg(errp, "missing chardev");
 171         return;
 172     }
 173
 174     if (!fs->conf.tag) {
 175         error_setg(errp, "missing tag property");
 176         return;
 177     }
 178     len = strlen(fs->conf.tag);
 179     if (len == 0) {
 180         error_setg(errp, "tag property cannot be empty");
 181         return;
 182     }
 183     if (len > sizeof_field(struct virtio_fs_config, tag)) {
 184         error_setg(errp, "tag property must be %zu bytes or less",
 185                    sizeof_field(struct virtio_fs_config, tag));
 186         return;
 187     }
 188
 189     if (fs->conf.num_request_queues == 0) {
 190         error_setg(errp, "num-request-queues property must be larger than 0");
 191         return;
 192     }
 193
 194     if (!is_power_of_2(fs->conf.queue_size)) {
 195         error_setg(errp, "queue-size property must be a power of 2");
 196         return;
 197     }
 198
 199     if (fs->conf.queue_size > VIRTQUEUE_MAX_SIZE) {
 200         error_setg(errp, "queue-size property must be %u or smaller",
 201                    VIRTQUEUE_MAX_SIZE);
 202         return;
 203     }
 204
 205     if (!vhost_user_init(&fs->vhost_user, &fs->conf.chardev, errp)) {
 206         return;
 207     }
 208
 209     virtio_init(vdev, "vhost-user-fs", VIRTIO_ID_FS,
 210                 sizeof(struct virtio_fs_config));
 211
 212     /* Hiprio queue */
 213     fs->hiprio_vq = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
 214
 215     /* Request queues */
 216     fs->req_vqs = g_new(VirtQueue *, fs->conf.num_request_queues);
 217     for (i = 0; i < fs->conf.num_request_queues; i++) {
 218         fs->req_vqs[i] = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
 219     }
 220
 221     /* 1 high prio queue, plus the number configured */
 222     fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues;
 223     fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
 224     ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
 225                          VHOST_BACKEND_TYPE_USER, 0);
 226     if (ret < 0) {
 227         error_setg_errno(errp, -ret, "vhost_dev_init failed");
 228         goto err_virtio;
 229     }
 230
 231     return;
 232
 233 err_virtio:
 234     vhost_user_cleanup(&fs->vhost_user);
 235     virtio_delete_queue(fs->hiprio_vq);
 236     for (i = 0; i < fs->conf.num_request_queues; i++) {
 237         virtio_delete_queue(fs->req_vqs[i]);
 238     }
 239     g_free(fs->req_vqs);
 240     virtio_cleanup(vdev);
 241     g_free(fs->vhost_dev.vqs);
 242     return;
 243 }
 244
 245 static void vuf_device_unrealize(DeviceState *dev)
 246 {
 247     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 248     VHostUserFS *fs = VHOST_USER_FS(dev);
 249     int i;
 250
 251     /* This will stop vhost backend if appropriate. */
 252     vuf_set_status(vdev, 0);
 253
 254     vhost_dev_cleanup(&fs->vhost_dev);
 255
 256     vhost_user_cleanup(&fs->vhost_user);
 257
 258     virtio_delete_queue(fs->hiprio_vq);
 259     for (i = 0; i < fs->conf.num_request_queues; i++) {
 260         virtio_delete_queue(fs->req_vqs[i]);
 261     }
 262     g_free(fs->req_vqs);
 263     virtio_cleanup(vdev);
 264     g_free(fs->vhost_dev.vqs);
 265     fs->vhost_dev.vqs = NULL;
 266 }
 267
 268 static const VMStateDescription vuf_vmstate = {
 269     .name = "vhost-user-fs",
 270     .unmigratable = 1,
 271 };
 272
 273 static Property vuf_properties[] = {
 274     DEFINE_PROP_CHR("chardev", VHostUserFS, conf.chardev),
 275     DEFINE_PROP_STRING("tag", VHostUserFS, conf.tag),
 276     DEFINE_PROP_UINT16("num-request-queues", VHostUserFS,
 277                        conf.num_request_queues, 1),
 278     DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
 279     DEFINE_PROP_END_OF_LIST(),
 280 };
 281
 282 static void vuf_class_init(ObjectClass *klass, void *data)
 283 {
 284     DeviceClass *dc = DEVICE_CLASS(klass);
 285     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 286
 287     device_class_set_props(dc, vuf_properties);
 288     dc->vmsd = &vuf_vmstate;
 289     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 290     vdc->realize = vuf_device_realize;
 291     vdc->unrealize = vuf_device_unrealize;
 292     vdc->get_features = vuf_get_features;
 293     vdc->get_config = vuf_get_config;
 294     vdc->set_status = vuf_set_status;
 295     vdc->guest_notifier_mask = vuf_guest_notifier_mask;
 296     vdc->guest_notifier_pending = vuf_guest_notifier_pending;
 297 }
 298
 299 static const TypeInfo vuf_info = {
 300     .name = TYPE_VHOST_USER_FS,
 301     .parent = TYPE_VIRTIO_DEVICE,
 302     .instance_size = sizeof(VHostUserFS),
 303     .class_init = vuf_class_init,
 304 };
 305
 306 static void vuf_register_types(void)
 307 {
 308     type_register_static(&vuf_info);
 309 }
 310
 311 type_init(vuf_register_types)