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/virtio/virtio-bus.h"
  20 #include "hw/virtio/virtio-access.h"
  21 #include "qemu/error-report.h"
  22 #include "hw/virtio/vhost-user-fs.h"
  23 #include "monitor/monitor.h"
  24
  25 static void vuf_get_config(VirtIODevice *vdev, uint8_t *config)
  26 {
  27     VHostUserFS *fs = VHOST_USER_FS(vdev);
  28     struct virtio_fs_config fscfg = {};
  29
  30     memcpy((char *)fscfg.tag, fs->conf.tag,
  31            MIN(strlen(fs->conf.tag) + 1, sizeof(fscfg.tag)));
  32
  33     virtio_stl_p(vdev, &fscfg.num_request_queues, fs->conf.num_request_queues);
  34
  35     memcpy(config, &fscfg, sizeof(fscfg));
  36 }
  37
  38 static void vuf_start(VirtIODevice *vdev)
  39 {
  40     VHostUserFS *fs = VHOST_USER_FS(vdev);
  41     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
  42     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
  43     int ret;
  44     int i;
  45
  46     if (!k->set_guest_notifiers) {
  47         error_report("binding does not support guest notifiers");
  48         return;
  49     }
  50
  51     ret = vhost_dev_enable_notifiers(&fs->vhost_dev, vdev);
  52     if (ret < 0) {
  53         error_report("Error enabling host notifiers: %d", -ret);
  54         return;
  55     }
  56
  57     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, true);
  58     if (ret < 0) {
  59         error_report("Error binding guest notifier: %d", -ret);
  60         goto err_host_notifiers;
  61     }
  62
  63     fs->vhost_dev.acked_features = vdev->guest_features;
  64     ret = vhost_dev_start(&fs->vhost_dev, vdev);
  65     if (ret < 0) {
  66         error_report("Error starting vhost: %d", -ret);
  67         goto err_guest_notifiers;
  68     }
  69
  70     /*
  71      * guest_notifier_mask/pending not used yet, so just unmask
  72      * everything here.  virtio-pci will do the right thing by
  73      * enabling/disabling irqfd.
  74      */
  75     for (i = 0; i < fs->vhost_dev.nvqs; i++) {
  76         vhost_virtqueue_mask(&fs->vhost_dev, vdev, i, false);
  77     }
  78
  79     return;
  80
  81 err_guest_notifiers:
  82     k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
  83 err_host_notifiers:
  84     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
  85 }
  86
  87 static void vuf_stop(VirtIODevice *vdev)
  88 {
  89     VHostUserFS *fs = VHOST_USER_FS(vdev);
  90     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
  91     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
  92     int ret;
  93
  94     if (!k->set_guest_notifiers) {
  95         return;
  96     }
  97
  98     vhost_dev_stop(&fs->vhost_dev, vdev);
  99
 100     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
 101     if (ret < 0) {
 102         error_report("vhost guest notifier cleanup failed: %d", ret);
 103         return;
 104     }
 105
 106     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
 107 }
 108
 109 static void vuf_set_status(VirtIODevice *vdev, uint8_t status)
 110 {
 111     VHostUserFS *fs = VHOST_USER_FS(vdev);
 112     bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
 113
 114     if (!vdev->vm_running) {
 115         should_start = false;
 116     }
 117
 118     if (fs->vhost_dev.started == should_start) {
 119         return;
 120     }
 121
 122     if (should_start) {
 123         vuf_start(vdev);
 124     } else {
 125         vuf_stop(vdev);
 126     }
 127 }
 128
 129 static uint64_t vuf_get_features(VirtIODevice *vdev,
 130                                       uint64_t requested_features,
 131                                       Error **errp)
 132 {
 133     /* No feature bits used yet */
 134     return requested_features;
 135 }
 136
 137 static void vuf_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 138 {
 139     /*
 140      * Not normally called; it's the daemon that handles the queue;
 141      * however virtio's cleanup path can call this.
 142      */
 143 }
 144
 145 static void vuf_guest_notifier_mask(VirtIODevice *vdev, int idx,
 146                                             bool mask)
 147 {
 148     VHostUserFS *fs = VHOST_USER_FS(vdev);
 149
 150     vhost_virtqueue_mask(&fs->vhost_dev, vdev, idx, mask);
 151 }
 152
 153 static bool vuf_guest_notifier_pending(VirtIODevice *vdev, int idx)
 154 {
 155     VHostUserFS *fs = VHOST_USER_FS(vdev);
 156
 157     return vhost_virtqueue_pending(&fs->vhost_dev, idx);
 158 }
 159
 160 static void vuf_device_realize(DeviceState *dev, Error **errp)
 161 {
 162     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 163     VHostUserFS *fs = VHOST_USER_FS(dev);
 164     unsigned int i;
 165     size_t len;
 166     int ret;
 167
 168     if (!fs->conf.chardev.chr) {
 169         error_setg(errp, "missing chardev");
 170         return;
 171     }
 172
 173     if (!fs->conf.tag) {
 174         error_setg(errp, "missing tag property");
 175         return;
 176     }
 177     len = strlen(fs->conf.tag);
 178     if (len == 0) {
 179         error_setg(errp, "tag property cannot be empty");
 180         return;
 181     }
 182     if (len > sizeof_field(struct virtio_fs_config, tag)) {
 183         error_setg(errp, "tag property must be %zu bytes or less",
 184                    sizeof_field(struct virtio_fs_config, tag));
 185         return;
 186     }
 187
 188     if (fs->conf.num_request_queues == 0) {
 189         error_setg(errp, "num-request-queues property must be larger than 0");
 190         return;
 191     }
 192
 193     if (!is_power_of_2(fs->conf.queue_size)) {
 194         error_setg(errp, "queue-size property must be a power of 2");
 195         return;
 196     }
 197
 198     if (fs->conf.queue_size > VIRTQUEUE_MAX_SIZE) {
 199         error_setg(errp, "queue-size property must be %u or smaller",
 200                    VIRTQUEUE_MAX_SIZE);
 201         return;
 202     }
 203
 204     if (!vhost_user_init(&fs->vhost_user, &fs->conf.chardev, errp)) {
 205         return;
 206     }
 207
 208     virtio_init(vdev, "vhost-user-fs", VIRTIO_ID_FS,
 209                 sizeof(struct virtio_fs_config));
 210
 211     /* Hiprio queue */
 212     fs->hiprio_vq = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
 213
 214     /* Request queues */
 215     fs->req_vqs = g_new(VirtQueue *, fs->conf.num_request_queues);
 216     for (i = 0; i < fs->conf.num_request_queues; i++) {
 217         fs->req_vqs[i] = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
 218     }
 219
 220     /* 1 high prio queue, plus the number configured */
 221     fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues;
 222     fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
 223     ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
 224                          VHOST_BACKEND_TYPE_USER, 0);
 225     if (ret < 0) {
 226         error_setg_errno(errp, -ret, "vhost_dev_init failed");
 227         goto err_virtio;
 228     }
 229
 230     return;
 231
 232 err_virtio:
 233     vhost_user_cleanup(&fs->vhost_user);
 234     virtio_delete_queue(fs->hiprio_vq);
 235     for (i = 0; i < fs->conf.num_request_queues; i++) {
 236         virtio_delete_queue(fs->req_vqs[i]);
 237     }
 238     g_free(fs->req_vqs);
 239     virtio_cleanup(vdev);
 240     g_free(fs->vhost_dev.vqs);
 241     return;
 242 }
 243
 244 static void vuf_device_unrealize(DeviceState *dev)
 245 {
 246     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 247     VHostUserFS *fs = VHOST_USER_FS(dev);
 248     int i;
 249
 250     /* This will stop vhost backend if appropriate. */
 251     vuf_set_status(vdev, 0);
 252
 253     vhost_dev_cleanup(&fs->vhost_dev);
 254
 255     vhost_user_cleanup(&fs->vhost_user);
 256
 257     virtio_delete_queue(fs->hiprio_vq);
 258     for (i = 0; i < fs->conf.num_request_queues; i++) {
 259         virtio_delete_queue(fs->req_vqs[i]);
 260     }
 261     g_free(fs->req_vqs);
 262     virtio_cleanup(vdev);
 263     g_free(fs->vhost_dev.vqs);
 264     fs->vhost_dev.vqs = NULL;
 265 }
 266
 267 static const VMStateDescription vuf_vmstate = {
 268     .name = "vhost-user-fs",
 269     .unmigratable = 1,
 270 };
 271
 272 static Property vuf_properties[] = {
 273     DEFINE_PROP_CHR("chardev", VHostUserFS, conf.chardev),
 274     DEFINE_PROP_STRING("tag", VHostUserFS, conf.tag),
 275     DEFINE_PROP_UINT16("num-request-queues", VHostUserFS,
 276                        conf.num_request_queues, 1),
 277     DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
 278     DEFINE_PROP_END_OF_LIST(),
 279 };
 280
 281 static void vuf_class_init(ObjectClass *klass, void *data)
 282 {
 283     DeviceClass *dc = DEVICE_CLASS(klass);
 284     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 285
 286     device_class_set_props(dc, vuf_properties);
 287     dc->vmsd = &vuf_vmstate;
 288     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 289     vdc->realize = vuf_device_realize;
 290     vdc->unrealize = vuf_device_unrealize;
 291     vdc->get_features = vuf_get_features;
 292     vdc->get_config = vuf_get_config;
 293     vdc->set_status = vuf_set_status;
 294     vdc->guest_notifier_mask = vuf_guest_notifier_mask;
 295     vdc->guest_notifier_pending = vuf_guest_notifier_pending;
 296 }
 297
 298 static const TypeInfo vuf_info = {
 299     .name = TYPE_VHOST_USER_FS,
 300     .parent = TYPE_VIRTIO_DEVICE,
 301     .instance_size = sizeof(VHostUserFS),
 302     .class_init = vuf_class_init,
 303 };
 304
 305 static void vuf_register_types(void)
 306 {
 307     type_register_static(&vuf_info);
 308 }
 309
 310 type_init(vuf_register_types)