hw/virtio/virtio-bus.c

   1 /*
   2  * VirtioBus
   3  *
   4  *  Copyright (C) 2012 : GreenSocs Ltd
   5  *      http://www.greensocs.com/ , email: info@greensocs.com
   6  *
   7  *  Developed by :
   8  *  Frederic Konrad   <fred.konrad@greensocs.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation, either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License along
  21  * with this program; if not, see <http://www.gnu.org/licenses/>.
  22  *
  23  */
  24
  25 #include "qemu/osdep.h"
  26 #include "qemu/error-report.h"
  27 #include "qemu/module.h"
  28 #include "qapi/error.h"
  29 #include "hw/virtio/virtio-bus.h"
  30 #include "hw/virtio/virtio.h"
  31 #include "exec/address-spaces.h"
  32
  33 /* #define DEBUG_VIRTIO_BUS */
  34
  35 #ifdef DEBUG_VIRTIO_BUS
  36 #define DPRINTF(fmt, ...) \
  37 do { printf("virtio_bus: " fmt , ## __VA_ARGS__); } while (0)
  38 #else
  39 #define DPRINTF(fmt, ...) do { } while (0)
  40 #endif
  41
  42 /* A VirtIODevice is being plugged */
  43 void virtio_bus_device_plugged(VirtIODevice *vdev, Error **errp)
  44 {
  45     DeviceState *qdev = DEVICE(vdev);
  46     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
  47     VirtioBusState *bus = VIRTIO_BUS(qbus);
  48     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
  49     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
  50     bool has_iommu = virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
  51     Error *local_err = NULL;
  52
  53     DPRINTF("%s: plug device.\n", qbus->name);
  54
  55     if (klass->pre_plugged != NULL) {
  56         klass->pre_plugged(qbus->parent, &local_err);
  57         if (local_err) {
  58             error_propagate(errp, local_err);
  59             return;
  60         }
  61     }
  62
  63     /* Get the features of the plugged device. */
  64     assert(vdc->get_features != NULL);
  65     vdev->host_features = vdc->get_features(vdev, vdev->host_features,
  66                                             &local_err);
  67     if (local_err) {
  68         error_propagate(errp, local_err);
  69         return;
  70     }
  71
  72     if (klass->device_plugged != NULL) {
  73         klass->device_plugged(qbus->parent, &local_err);
  74     }
  75     if (local_err) {
  76         error_propagate(errp, local_err);
  77         return;
  78     }
  79
  80     if (klass->get_dma_as != NULL && has_iommu) {
  81         virtio_add_feature(&vdev->host_features, VIRTIO_F_IOMMU_PLATFORM);
  82         vdev->dma_as = klass->get_dma_as(qbus->parent);
  83     } else {
  84         vdev->dma_as = &address_space_memory;
  85     }
  86 }
  87
  88 /* Reset the virtio_bus */
  89 void virtio_bus_reset(VirtioBusState *bus)
  90 {
  91     VirtIODevice *vdev = virtio_bus_get_device(bus);
  92
  93     DPRINTF("%s: reset device.\n", BUS(bus)->name);
  94     if (vdev != NULL) {
  95         virtio_reset(vdev);
  96     }
  97 }
  98
  99 /* A VirtIODevice is being unplugged */
 100 void virtio_bus_device_unplugged(VirtIODevice *vdev)
 101 {
 102     DeviceState *qdev = DEVICE(vdev);
 103     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
 104     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(qbus);
 105
 106     DPRINTF("%s: remove device.\n", qbus->name);
 107
 108     if (vdev != NULL) {
 109         if (klass->device_unplugged != NULL) {
 110             klass->device_unplugged(qbus->parent);
 111         }
 112     }
 113 }
 114
 115 /* Get the device id of the plugged device. */
 116 uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
 117 {
 118     VirtIODevice *vdev = virtio_bus_get_device(bus);
 119     assert(vdev != NULL);
 120     return vdev->device_id;
 121 }
 122
 123 /* Get the config_len field of the plugged device. */
 124 size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
 125 {
 126     VirtIODevice *vdev = virtio_bus_get_device(bus);
 127     assert(vdev != NULL);
 128     return vdev->config_len;
 129 }
 130
 131 /* Get bad features of the plugged device. */
 132 uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus)
 133 {
 134     VirtIODevice *vdev = virtio_bus_get_device(bus);
 135     VirtioDeviceClass *k;
 136
 137     assert(vdev != NULL);
 138     k = VIRTIO_DEVICE_GET_CLASS(vdev);
 139     if (k->bad_features != NULL) {
 140         return k->bad_features(vdev);
 141     } else {
 142         return 0;
 143     }
 144 }
 145
 146 /* Get config of the plugged device. */
 147 void virtio_bus_get_vdev_config(VirtioBusState *bus, uint8_t *config)
 148 {
 149     VirtIODevice *vdev = virtio_bus_get_device(bus);
 150     VirtioDeviceClass *k;
 151
 152     assert(vdev != NULL);
 153     k = VIRTIO_DEVICE_GET_CLASS(vdev);
 154     if (k->get_config != NULL) {
 155         k->get_config(vdev, config);
 156     }
 157 }
 158
 159 /* Set config of the plugged device. */
 160 void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config)
 161 {
 162     VirtIODevice *vdev = virtio_bus_get_device(bus);
 163     VirtioDeviceClass *k;
 164
 165     assert(vdev != NULL);
 166     k = VIRTIO_DEVICE_GET_CLASS(vdev);
 167     if (k->set_config != NULL) {
 168         k->set_config(vdev, config);
 169     }
 170 }
 171
 172 /* On success, ioeventfd ownership belongs to the caller.  */
 173 int virtio_bus_grab_ioeventfd(VirtioBusState *bus)
 174 {
 175     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 176
 177     /* vhost can be used even if ioeventfd=off in the proxy device,
 178      * so do not check k->ioeventfd_enabled.
 179      */
 180     if (!k->ioeventfd_assign) {
 181         return -ENOSYS;
 182     }
 183
 184     if (bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
 185         virtio_bus_stop_ioeventfd(bus);
 186         /* Remember that we need to restart ioeventfd
 187          * when ioeventfd_grabbed becomes zero.
 188          */
 189         bus->ioeventfd_started = true;
 190     }
 191     bus->ioeventfd_grabbed++;
 192     return 0;
 193 }
 194
 195 void virtio_bus_release_ioeventfd(VirtioBusState *bus)
 196 {
 197     assert(bus->ioeventfd_grabbed != 0);
 198     if (--bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
 199         /* Force virtio_bus_start_ioeventfd to act.  */
 200         bus->ioeventfd_started = false;
 201         virtio_bus_start_ioeventfd(bus);
 202     }
 203 }
 204
 205 int virtio_bus_start_ioeventfd(VirtioBusState *bus)
 206 {
 207     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 208     DeviceState *proxy = DEVICE(BUS(bus)->parent);
 209     VirtIODevice *vdev = virtio_bus_get_device(bus);
 210     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
 211     int r;
 212
 213     if (!k->ioeventfd_assign || !k->ioeventfd_enabled(proxy)) {
 214         return -ENOSYS;
 215     }
 216     if (bus->ioeventfd_started) {
 217         return 0;
 218     }
 219
 220     /* Only set our notifier if we have ownership.  */
 221     if (!bus->ioeventfd_grabbed) {
 222         r = vdc->start_ioeventfd(vdev);
 223         if (r < 0) {
 224             error_report("%s: failed. Fallback to userspace (slower).", __func__);
 225             return r;
 226         }
 227     }
 228     bus->ioeventfd_started = true;
 229     return 0;
 230 }
 231
 232 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
 233 {
 234     VirtIODevice *vdev;
 235     VirtioDeviceClass *vdc;
 236
 237     if (!bus->ioeventfd_started) {
 238         return;
 239     }
 240
 241     /* Only remove our notifier if we have ownership.  */
 242     if (!bus->ioeventfd_grabbed) {
 243         vdev = virtio_bus_get_device(bus);
 244         vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
 245         vdc->stop_ioeventfd(vdev);
 246     }
 247     bus->ioeventfd_started = false;
 248 }
 249
 250 bool virtio_bus_ioeventfd_enabled(VirtioBusState *bus)
 251 {
 252     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 253     DeviceState *proxy = DEVICE(BUS(bus)->parent);
 254
 255     return k->ioeventfd_assign && k->ioeventfd_enabled(proxy);
 256 }
 257
 258 /*
 259  * This function switches ioeventfd on/off in the device.
 260  * The caller must set or clear the handlers for the EventNotifier.
 261  */
 262 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
 263 {
 264     VirtIODevice *vdev = virtio_bus_get_device(bus);
 265     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 266     DeviceState *proxy = DEVICE(BUS(bus)->parent);
 267     VirtQueue *vq = virtio_get_queue(vdev, n);
 268     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
 269     int r = 0;
 270
 271     if (!k->ioeventfd_assign) {
 272         return -ENOSYS;
 273     }
 274
 275     if (assign) {
 276         r = event_notifier_init(notifier, 1);
 277         if (r < 0) {
 278             error_report("%s: unable to init event notifier: %s (%d)",
 279                          __func__, strerror(-r), r);
 280             return r;
 281         }
 282         r = k->ioeventfd_assign(proxy, notifier, n, true);
 283         if (r < 0) {
 284             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
 285             virtio_bus_cleanup_host_notifier(bus, n);
 286         }
 287     } else {
 288         k->ioeventfd_assign(proxy, notifier, n, false);
 289     }
 290
 291     if (r == 0) {
 292         virtio_queue_set_host_notifier_enabled(vq, assign);
 293     }
 294
 295     return r;
 296 }
 297
 298 void virtio_bus_cleanup_host_notifier(VirtioBusState *bus, int n)
 299 {
 300     VirtIODevice *vdev = virtio_bus_get_device(bus);
 301     VirtQueue *vq = virtio_get_queue(vdev, n);
 302     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
 303
 304     /* Test and clear notifier after disabling event,
 305      * in case poll callback didn't have time to run.
 306      */
 307     virtio_queue_host_notifier_read(notifier);
 308     event_notifier_cleanup(notifier);
 309 }
 310
 311 static char *virtio_bus_get_dev_path(DeviceState *dev)
 312 {
 313     BusState *bus = qdev_get_parent_bus(dev);
 314     DeviceState *proxy = DEVICE(bus->parent);
 315     return qdev_get_dev_path(proxy);
 316 }
 317
 318 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
 319 {
 320     return NULL;
 321 }
 322
 323 static void virtio_bus_class_init(ObjectClass *klass, void *data)
 324 {
 325     BusClass *bus_class = BUS_CLASS(klass);
 326     bus_class->get_dev_path = virtio_bus_get_dev_path;
 327     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
 328 }
 329
 330 static const TypeInfo virtio_bus_info = {
 331     .name = TYPE_VIRTIO_BUS,
 332     .parent = TYPE_BUS,
 333     .instance_size = sizeof(VirtioBusState),
 334     .abstract = true,
 335     .class_size = sizeof(VirtioBusClass),
 336     .class_init = virtio_bus_class_init
 337 };
 338
 339 static void virtio_register_types(void)
 340 {
 341     type_register_static(&virtio_bus_info);
 342 }
 343
 344 type_init(virtio_register_types)