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