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 void vuf_get_config(VirtIODevice *vdev, uint8_t *config)
  28 {
  29     VHostUserFS *fs = VHOST_USER_FS(vdev);
  30     struct virtio_fs_config fscfg = {};
  31
  32     memcpy((char *)fscfg.tag, fs->conf.tag,
  33            MIN(strlen(fs->conf.tag) + 1, sizeof(fscfg.tag)));
  34
  35     virtio_stl_p(vdev, &fscfg.num_request_queues, fs->conf.num_request_queues);
  36
  37     memcpy(config, &fscfg, sizeof(fscfg));
  38 }
  39
  40 static void vuf_start(VirtIODevice *vdev)
  41 {
  42     VHostUserFS *fs = VHOST_USER_FS(vdev);
  43     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
  44     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
  45     int ret;
  46     int i;
  47
  48     if (!k->set_guest_notifiers) {
  49         error_report("binding does not support guest notifiers");
  50         return;
  51     }
  52
  53     ret = vhost_dev_enable_notifiers(&fs->vhost_dev, vdev);
  54     if (ret < 0) {
  55         error_report("Error enabling host notifiers: %d", -ret);
  56         return;
  57     }
  58
  59     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, true);
  60     if (ret < 0) {
  61         error_report("Error binding guest notifier: %d", -ret);
  62         goto err_host_notifiers;
  63     }
  64
  65     fs->vhost_dev.acked_features = vdev->guest_features;
  66     ret = vhost_dev_start(&fs->vhost_dev, vdev);
  67     if (ret < 0) {
  68         error_report("Error starting vhost: %d", -ret);
  69         goto err_guest_notifiers;
  70     }
  71
  72     /*
  73      * guest_notifier_mask/pending not used yet, so just unmask
  74      * everything here.  virtio-pci will do the right thing by
  75      * enabling/disabling irqfd.
  76      */
  77     for (i = 0; i < fs->vhost_dev.nvqs; i++) {
  78         vhost_virtqueue_mask(&fs->vhost_dev, vdev, i, false);
  79     }
  80
  81     return;
  82
  83 err_guest_notifiers:
  84     k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
  85 err_host_notifiers:
  86     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
  87 }
  88
  89 static void vuf_stop(VirtIODevice *vdev)
  90 {
  91     VHostUserFS *fs = VHOST_USER_FS(vdev);
  92     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
  93     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
  94     int ret;
  95
  96     if (!k->set_guest_notifiers) {
  97         return;
  98     }
  99
 100     vhost_dev_stop(&fs->vhost_dev, vdev);
 101
 102     ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
 103     if (ret < 0) {
 104         error_report("vhost guest notifier cleanup failed: %d", ret);
 105         return;
 106     }
 107
 108     vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
 109 }
 110
 111 static void vuf_set_status(VirtIODevice *vdev, uint8_t status)
 112 {
 113     VHostUserFS *fs = VHOST_USER_FS(vdev);
 114     bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
 115
 116     if (!vdev->vm_running) {
 117         should_start = false;
 118     }
 119
 120     if (fs->vhost_dev.started == should_start) {
 121         return;
 122     }
 123
 124     if (should_start) {
 125         vuf_start(vdev);
 126     } else {
 127         vuf_stop(vdev);
 128     }
 129 }
 130
 131 static uint64_t vuf_get_features(VirtIODevice *vdev,
 132                                       uint64_t requested_features,
 133                                       Error **errp)
 134 {
 135     /* No feature bits used yet */
 136     return requested_features;
 137 }
 138
 139 static void vuf_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 140 {
 141     /*
 142      * Not normally called; it's the daemon that handles the queue;
 143      * however virtio's cleanup path can call this.
 144      */
 145 }
 146
 147 static void vuf_guest_notifier_mask(VirtIODevice *vdev, int idx,
 148                                             bool mask)
 149 {
 150     VHostUserFS *fs = VHOST_USER_FS(vdev);
 151
 152     vhost_virtqueue_mask(&fs->vhost_dev, vdev, idx, mask);
 153 }
 154
 155 static bool vuf_guest_notifier_pending(VirtIODevice *vdev, int idx)
 156 {
 157     VHostUserFS *fs = VHOST_USER_FS(vdev);
 158
 159     return vhost_virtqueue_pending(&fs->vhost_dev, idx);
 160 }
 161
 162 static void vuf_device_realize(DeviceState *dev, Error **errp)
 163 {
 164     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 165     VHostUserFS *fs = VHOST_USER_FS(dev);
 166     unsigned int i;
 167     size_t len;
 168     int ret;
 169
 170     if (!fs->conf.chardev.chr) {
 171         error_setg(errp, "missing chardev");
 172         return;
 173     }
 174
 175     if (!fs->conf.tag) {
 176         error_setg(errp, "missing tag property");
 177         return;
 178     }
 179     len = strlen(fs->conf.tag);
 180     if (len == 0) {
 181         error_setg(errp, "tag property cannot be empty");
 182         return;
 183     }
 184     if (len > sizeof_field(struct virtio_fs_config, tag)) {
 185         error_setg(errp, "tag property must be %zu bytes or less",
 186                    sizeof_field(struct virtio_fs_config, tag));
 187         return;
 188     }
 189
 190     if (fs->conf.num_request_queues == 0) {
 191         error_setg(errp, "num-request-queues property must be larger than 0");
 192         return;
 193     }
 194
 195     if (!is_power_of_2(fs->conf.queue_size)) {
 196         error_setg(errp, "queue-size property must be a power of 2");
 197         return;
 198     }
 199
 200     if (fs->conf.queue_size > VIRTQUEUE_MAX_SIZE) {
 201         error_setg(errp, "queue-size property must be %u or smaller",
 202                    VIRTQUEUE_MAX_SIZE);
 203         return;
 204     }
 205
 206     if (!vhost_user_init(&fs->vhost_user, &fs->conf.chardev, errp)) {
 207         return;
 208     }
 209
 210     virtio_init(vdev, "vhost-user-fs", VIRTIO_ID_FS,
 211                 sizeof(struct virtio_fs_config));
 212
 213     /* Hiprio queue */
 214     fs->hiprio_vq = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
 215
 216     /* Request queues */
 217     fs->req_vqs = g_new(VirtQueue *, fs->conf.num_request_queues);
 218     for (i = 0; i < fs->conf.num_request_queues; i++) {
 219         fs->req_vqs[i] = virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
 220     }
 221
 222     /* 1 high prio queue, plus the number configured */
 223     fs->vhost_dev.nvqs = 1 + fs->conf.num_request_queues;
 224     fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
 225     ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
 226                          VHOST_BACKEND_TYPE_USER, 0);
 227     if (ret < 0) {
 228         error_setg_errno(errp, -ret, "vhost_dev_init failed");
 229         goto err_virtio;
 230     }
 231
 232     return;
 233
 234 err_virtio:
 235     vhost_user_cleanup(&fs->vhost_user);
 236     virtio_delete_queue(fs->hiprio_vq);
 237     for (i = 0; i < fs->conf.num_request_queues; i++) {
 238         virtio_delete_queue(fs->req_vqs[i]);
 239     }
 240     g_free(fs->req_vqs);
 241     virtio_cleanup(vdev);
 242     g_free(fs->vhost_dev.vqs);
 243     return;
 244 }
 245
 246 static void vuf_device_unrealize(DeviceState *dev)
 247 {
 248     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 249     VHostUserFS *fs = VHOST_USER_FS(dev);
 250     int i;
 251
 252     /* This will stop vhost backend if appropriate. */
 253     vuf_set_status(vdev, 0);
 254
 255     vhost_dev_cleanup(&fs->vhost_dev);
 256
 257     vhost_user_cleanup(&fs->vhost_user);
 258
 259     virtio_delete_queue(fs->hiprio_vq);
 260     for (i = 0; i < fs->conf.num_request_queues; i++) {
 261         virtio_delete_queue(fs->req_vqs[i]);
 262     }
 263     g_free(fs->req_vqs);
 264     virtio_cleanup(vdev);
 265     g_free(fs->vhost_dev.vqs);
 266     fs->vhost_dev.vqs = NULL;
 267 }
 268
 269 static const VMStateDescription vuf_vmstate = {
 270     .name = "vhost-user-fs",
 271     .unmigratable = 1,
 272 };
 273
 274 static Property vuf_properties[] = {
 275     DEFINE_PROP_CHR("chardev", VHostUserFS, conf.chardev),
 276     DEFINE_PROP_STRING("tag", VHostUserFS, conf.tag),
 277     DEFINE_PROP_UINT16("num-request-queues", VHostUserFS,
 278                        conf.num_request_queues, 1),
 279     DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
 280     DEFINE_PROP_END_OF_LIST(),
 281 };
 282
 283 static void vuf_instance_init(Object *obj)
 284 {
 285     VHostUserFS *fs = VHOST_USER_FS(obj);
 286
 287     device_add_bootindex_property(obj, &fs->bootindex, "bootindex",
 288                                   "/filesystem@0", DEVICE(obj));
 289 }
 290
 291 static void vuf_class_init(ObjectClass *klass, void *data)
 292 {
 293     DeviceClass *dc = DEVICE_CLASS(klass);
 294     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 295
 296     device_class_set_props(dc, vuf_properties);
 297     dc->vmsd = &vuf_vmstate;
 298     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
 299     vdc->realize = vuf_device_realize;
 300     vdc->unrealize = vuf_device_unrealize;
 301     vdc->get_features = vuf_get_features;
 302     vdc->get_config = vuf_get_config;
 303     vdc->set_status = vuf_set_status;
 304     vdc->guest_notifier_mask = vuf_guest_notifier_mask;
 305     vdc->guest_notifier_pending = vuf_guest_notifier_pending;
 306 }
 307
 308 static const TypeInfo vuf_info = {
 309     .name = TYPE_VHOST_USER_FS,
 310     .parent = TYPE_VIRTIO_DEVICE,
 311     .instance_size = sizeof(VHostUserFS),
 312     .instance_init = vuf_instance_init,
 313     .class_init = vuf_class_init,
 314 };
 315
 316 static void vuf_register_types(void)
 317 {
 318     type_register_static(&vuf_info);
 319 }
 320
 321 type_init(vuf_register_types)