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