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 (has_iommu && !virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM)) {
  73         error_setg(errp, "iommu_platform=true is not supported by the device");
  74         return;
  75     }
  76
  77     if (klass->device_plugged != NULL) {
  78         klass->device_plugged(qbus->parent, &local_err);
  79     }
  80     if (local_err) {
  81         error_propagate(errp, local_err);
  82         return;
  83     }
  84
  85     if (klass->get_dma_as != NULL && has_iommu) {
  86         virtio_add_feature(&vdev->host_features, VIRTIO_F_IOMMU_PLATFORM);
  87         vdev->dma_as = klass->get_dma_as(qbus->parent);
  88     } else {
  89         vdev->dma_as = &address_space_memory;
  90     }
  91 }
  92
  93 /* Reset the virtio_bus */
  94 void virtio_bus_reset(VirtioBusState *bus)
  95 {
  96     VirtIODevice *vdev = virtio_bus_get_device(bus);
  97
  98     DPRINTF("%s: reset device.\n", BUS(bus)->name);
  99     if (vdev != NULL) {
 100         virtio_reset(vdev);
 101     }
 102 }
 103
 104 /* A VirtIODevice is being unplugged */
 105 void virtio_bus_device_unplugged(VirtIODevice *vdev)
 106 {
 107     DeviceState *qdev = DEVICE(vdev);
 108     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
 109     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(qbus);
 110
 111     DPRINTF("%s: remove device.\n", qbus->name);
 112
 113     if (vdev != NULL) {
 114         if (klass->device_unplugged != NULL) {
 115             klass->device_unplugged(qbus->parent);
 116         }
 117     }
 118 }
 119
 120 /* Get the device id of the plugged device. */
 121 uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
 122 {
 123     VirtIODevice *vdev = virtio_bus_get_device(bus);
 124     assert(vdev != NULL);
 125     return vdev->device_id;
 126 }
 127
 128 /* Get the config_len field of the plugged device. */
 129 size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
 130 {
 131     VirtIODevice *vdev = virtio_bus_get_device(bus);
 132     assert(vdev != NULL);
 133     return vdev->config_len;
 134 }
 135
 136 /* Get bad features of the plugged device. */
 137 uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus)
 138 {
 139     VirtIODevice *vdev = virtio_bus_get_device(bus);
 140     VirtioDeviceClass *k;
 141
 142     assert(vdev != NULL);
 143     k = VIRTIO_DEVICE_GET_CLASS(vdev);
 144     if (k->bad_features != NULL) {
 145         return k->bad_features(vdev);
 146     } else {
 147         return 0;
 148     }
 149 }
 150
 151 /* Get config of the plugged device. */
 152 void virtio_bus_get_vdev_config(VirtioBusState *bus, uint8_t *config)
 153 {
 154     VirtIODevice *vdev = virtio_bus_get_device(bus);
 155     VirtioDeviceClass *k;
 156
 157     assert(vdev != NULL);
 158     k = VIRTIO_DEVICE_GET_CLASS(vdev);
 159     if (k->get_config != NULL) {
 160         k->get_config(vdev, config);
 161     }
 162 }
 163
 164 /* Set config of the plugged device. */
 165 void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config)
 166 {
 167     VirtIODevice *vdev = virtio_bus_get_device(bus);
 168     VirtioDeviceClass *k;
 169
 170     assert(vdev != NULL);
 171     k = VIRTIO_DEVICE_GET_CLASS(vdev);
 172     if (k->set_config != NULL) {
 173         k->set_config(vdev, config);
 174     }
 175 }
 176
 177 /* On success, ioeventfd ownership belongs to the caller.  */
 178 int virtio_bus_grab_ioeventfd(VirtioBusState *bus)
 179 {
 180     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 181
 182     /* vhost can be used even if ioeventfd=off in the proxy device,
 183      * so do not check k->ioeventfd_enabled.
 184      */
 185     if (!k->ioeventfd_assign) {
 186         return -ENOSYS;
 187     }
 188
 189     if (bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
 190         virtio_bus_stop_ioeventfd(bus);
 191         /* Remember that we need to restart ioeventfd
 192          * when ioeventfd_grabbed becomes zero.
 193          */
 194         bus->ioeventfd_started = true;
 195     }
 196     bus->ioeventfd_grabbed++;
 197     return 0;
 198 }
 199
 200 void virtio_bus_release_ioeventfd(VirtioBusState *bus)
 201 {
 202     assert(bus->ioeventfd_grabbed != 0);
 203     if (--bus->ioeventfd_grabbed == 0 && bus->ioeventfd_started) {
 204         /* Force virtio_bus_start_ioeventfd to act.  */
 205         bus->ioeventfd_started = false;
 206         virtio_bus_start_ioeventfd(bus);
 207     }
 208 }
 209
 210 int virtio_bus_start_ioeventfd(VirtioBusState *bus)
 211 {
 212     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 213     DeviceState *proxy = DEVICE(BUS(bus)->parent);
 214     VirtIODevice *vdev = virtio_bus_get_device(bus);
 215     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
 216     int r;
 217
 218     if (!k->ioeventfd_assign || !k->ioeventfd_enabled(proxy)) {
 219         return -ENOSYS;
 220     }
 221     if (bus->ioeventfd_started) {
 222         return 0;
 223     }
 224
 225     /* Only set our notifier if we have ownership.  */
 226     if (!bus->ioeventfd_grabbed) {
 227         r = vdc->start_ioeventfd(vdev);
 228         if (r < 0) {
 229             error_report("%s: failed. Fallback to userspace (slower).", __func__);
 230             return r;
 231         }
 232     }
 233     bus->ioeventfd_started = true;
 234     return 0;
 235 }
 236
 237 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
 238 {
 239     VirtIODevice *vdev;
 240     VirtioDeviceClass *vdc;
 241
 242     if (!bus->ioeventfd_started) {
 243         return;
 244     }
 245
 246     /* Only remove our notifier if we have ownership.  */
 247     if (!bus->ioeventfd_grabbed) {
 248         vdev = virtio_bus_get_device(bus);
 249         vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
 250         vdc->stop_ioeventfd(vdev);
 251     }
 252     bus->ioeventfd_started = false;
 253 }
 254
 255 bool virtio_bus_ioeventfd_enabled(VirtioBusState *bus)
 256 {
 257     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 258     DeviceState *proxy = DEVICE(BUS(bus)->parent);
 259
 260     return k->ioeventfd_assign && k->ioeventfd_enabled(proxy);
 261 }
 262
 263 /*
 264  * This function switches ioeventfd on/off in the device.
 265  * The caller must set or clear the handlers for the EventNotifier.
 266  */
 267 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
 268 {
 269     VirtIODevice *vdev = virtio_bus_get_device(bus);
 270     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 271     DeviceState *proxy = DEVICE(BUS(bus)->parent);
 272     VirtQueue *vq = virtio_get_queue(vdev, n);
 273     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
 274     int r = 0;
 275
 276     if (!k->ioeventfd_assign) {
 277         return -ENOSYS;
 278     }
 279
 280     if (assign) {
 281         r = event_notifier_init(notifier, 1);
 282         if (r < 0) {
 283             error_report("%s: unable to init event notifier: %s (%d)",
 284                          __func__, strerror(-r), r);
 285             return r;
 286         }
 287         r = k->ioeventfd_assign(proxy, notifier, n, true);
 288         if (r < 0) {
 289             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
 290             virtio_bus_cleanup_host_notifier(bus, n);
 291         }
 292     } else {
 293         k->ioeventfd_assign(proxy, notifier, n, false);
 294     }
 295
 296     if (r == 0) {
 297         virtio_queue_set_host_notifier_enabled(vq, assign);
 298     }
 299
 300     return r;
 301 }
 302
 303 void virtio_bus_cleanup_host_notifier(VirtioBusState *bus, int n)
 304 {
 305     VirtIODevice *vdev = virtio_bus_get_device(bus);
 306     VirtQueue *vq = virtio_get_queue(vdev, n);
 307     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
 308
 309     /* Test and clear notifier after disabling event,
 310      * in case poll callback didn't have time to run.
 311      */
 312     virtio_queue_host_notifier_read(notifier);
 313     event_notifier_cleanup(notifier);
 314 }
 315
 316 static char *virtio_bus_get_dev_path(DeviceState *dev)
 317 {
 318     BusState *bus = qdev_get_parent_bus(dev);
 319     DeviceState *proxy = DEVICE(bus->parent);
 320     return qdev_get_dev_path(proxy);
 321 }
 322
 323 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
 324 {
 325     return NULL;
 326 }
 327
 328 static void virtio_bus_class_init(ObjectClass *klass, void *data)
 329 {
 330     BusClass *bus_class = BUS_CLASS(klass);
 331     bus_class->get_dev_path = virtio_bus_get_dev_path;
 332     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
 333 }
 334
 335 static const TypeInfo virtio_bus_info = {
 336     .name = TYPE_VIRTIO_BUS,
 337     .parent = TYPE_BUS,
 338     .instance_size = sizeof(VirtioBusState),
 339     .abstract = true,
 340     .class_size = sizeof(VirtioBusClass),
 341     .class_init = virtio_bus_class_init
 342 };
 343
 344 static void virtio_register_types(void)
 345 {
 346     type_register_static(&virtio_bus_info);
 347 }
 348
 349 type_init(virtio_register_types)