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