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