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
  32 /* #define DEBUG_VIRTIO_BUS */
  33
  34 #ifdef DEBUG_VIRTIO_BUS
  35 #define DPRINTF(fmt, ...) \
  36 do { printf("virtio_bus: " fmt , ## __VA_ARGS__); } while (0)
  37 #else
  38 #define DPRINTF(fmt, ...) do { } while (0)
  39 #endif
  40
  41 /* A VirtIODevice is being plugged */
  42 void virtio_bus_device_plugged(VirtIODevice *vdev, Error **errp)
  43 {
  44     DeviceState *qdev = DEVICE(vdev);
  45     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
  46     VirtioBusState *bus = VIRTIO_BUS(qbus);
  47     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(bus);
  48     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
  49
  50     DPRINTF("%s: plug device.\n", qbus->name);
  51
  52     if (klass->device_plugged != NULL) {
  53         klass->device_plugged(qbus->parent, errp);
  54     }
  55
  56     /* Get the features of the plugged device. */
  57     assert(vdc->get_features != NULL);
  58     vdev->host_features = vdc->get_features(vdev, vdev->host_features,
  59                                             errp);
  60     if (klass->post_plugged != NULL) {
  61         klass->post_plugged(qbus->parent, errp);
  62     }
  63 }
  64
  65 /* Reset the virtio_bus */
  66 void virtio_bus_reset(VirtioBusState *bus)
  67 {
  68     VirtIODevice *vdev = virtio_bus_get_device(bus);
  69
  70     DPRINTF("%s: reset device.\n", BUS(bus)->name);
  71     if (vdev != NULL) {
  72         virtio_reset(vdev);
  73     }
  74 }
  75
  76 /* A VirtIODevice is being unplugged */
  77 void virtio_bus_device_unplugged(VirtIODevice *vdev)
  78 {
  79     DeviceState *qdev = DEVICE(vdev);
  80     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
  81     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(qbus);
  82
  83     DPRINTF("%s: remove device.\n", qbus->name);
  84
  85     if (vdev != NULL) {
  86         if (klass->device_unplugged != NULL) {
  87             klass->device_unplugged(qbus->parent);
  88         }
  89     }
  90 }
  91
  92 /* Get the device id of the plugged device. */
  93 uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
  94 {
  95     VirtIODevice *vdev = virtio_bus_get_device(bus);
  96     assert(vdev != NULL);
  97     return vdev->device_id;
  98 }
  99
 100 /* Get the config_len field of the plugged device. */
 101 size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
 102 {
 103     VirtIODevice *vdev = virtio_bus_get_device(bus);
 104     assert(vdev != NULL);
 105     return vdev->config_len;
 106 }
 107
 108 /* Get bad features of the plugged device. */
 109 uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus)
 110 {
 111     VirtIODevice *vdev = virtio_bus_get_device(bus);
 112     VirtioDeviceClass *k;
 113
 114     assert(vdev != NULL);
 115     k = VIRTIO_DEVICE_GET_CLASS(vdev);
 116     if (k->bad_features != NULL) {
 117         return k->bad_features(vdev);
 118     } else {
 119         return 0;
 120     }
 121 }
 122
 123 /* Get config of the plugged device. */
 124 void virtio_bus_get_vdev_config(VirtioBusState *bus, uint8_t *config)
 125 {
 126     VirtIODevice *vdev = virtio_bus_get_device(bus);
 127     VirtioDeviceClass *k;
 128
 129     assert(vdev != NULL);
 130     k = VIRTIO_DEVICE_GET_CLASS(vdev);
 131     if (k->get_config != NULL) {
 132         k->get_config(vdev, config);
 133     }
 134 }
 135
 136 /* Set config of the plugged device. */
 137 void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config)
 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->set_config != NULL) {
 145         k->set_config(vdev, config);
 146     }
 147 }
 148
 149 /*
 150  * This function handles both assigning the ioeventfd handler and
 151  * registering it with the kernel.
 152  * assign: register/deregister ioeventfd with the kernel
 153  * set_handler: use the generic ioeventfd handler
 154  */
 155 static int set_host_notifier_internal(DeviceState *proxy, VirtioBusState *bus,
 156                                       int n, bool assign, bool set_handler)
 157 {
 158     VirtIODevice *vdev = virtio_bus_get_device(bus);
 159     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 160     VirtQueue *vq = virtio_get_queue(vdev, n);
 161     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
 162     int r = 0;
 163
 164     if (assign) {
 165         r = event_notifier_init(notifier, 1);
 166         if (r < 0) {
 167             error_report("%s: unable to init event notifier: %d", __func__, r);
 168             return r;
 169         }
 170         virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler);
 171         r = k->ioeventfd_assign(proxy, notifier, n, assign);
 172         if (r < 0) {
 173             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
 174             virtio_queue_set_host_notifier_fd_handler(vq, false, false);
 175             event_notifier_cleanup(notifier);
 176             return r;
 177         }
 178     } else {
 179         virtio_queue_set_host_notifier_fd_handler(vq, false, false);
 180         k->ioeventfd_assign(proxy, notifier, n, assign);
 181         event_notifier_cleanup(notifier);
 182     }
 183     return r;
 184 }
 185
 186 void virtio_bus_start_ioeventfd(VirtioBusState *bus)
 187 {
 188     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 189     DeviceState *proxy = DEVICE(BUS(bus)->parent);
 190     VirtIODevice *vdev;
 191     int n, r;
 192
 193     if (!k->ioeventfd_started || k->ioeventfd_started(proxy)) {
 194         return;
 195     }
 196     if (k->ioeventfd_disabled(proxy)) {
 197         return;
 198     }
 199     vdev = virtio_bus_get_device(bus);
 200     for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
 201         if (!virtio_queue_get_num(vdev, n)) {
 202             continue;
 203         }
 204         r = set_host_notifier_internal(proxy, bus, n, true, true);
 205         if (r < 0) {
 206             goto assign_error;
 207         }
 208     }
 209     k->ioeventfd_set_started(proxy, true, false);
 210     return;
 211
 212 assign_error:
 213     while (--n >= 0) {
 214         if (!virtio_queue_get_num(vdev, n)) {
 215             continue;
 216         }
 217
 218         r = set_host_notifier_internal(proxy, bus, n, false, false);
 219         assert(r >= 0);
 220     }
 221     k->ioeventfd_set_started(proxy, false, true);
 222     error_report("%s: failed. Fallback to userspace (slower).", __func__);
 223 }
 224
 225 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
 226 {
 227     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 228     DeviceState *proxy = DEVICE(BUS(bus)->parent);
 229     VirtIODevice *vdev;
 230     int n, r;
 231
 232     if (!k->ioeventfd_started || !k->ioeventfd_started(proxy)) {
 233         return;
 234     }
 235     vdev = virtio_bus_get_device(bus);
 236     for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
 237         if (!virtio_queue_get_num(vdev, n)) {
 238             continue;
 239         }
 240         r = set_host_notifier_internal(proxy, bus, n, false, false);
 241         assert(r >= 0);
 242     }
 243     k->ioeventfd_set_started(proxy, false, false);
 244 }
 245
 246 /*
 247  * This function switches from/to the generic ioeventfd handler.
 248  * assign==false means 'use generic ioeventfd handler'.
 249  */
 250 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
 251 {
 252     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 253     DeviceState *proxy = DEVICE(BUS(bus)->parent);
 254     VirtIODevice *vdev = virtio_bus_get_device(bus);
 255     VirtQueue *vq = virtio_get_queue(vdev, n);
 256
 257     if (!k->ioeventfd_started) {
 258         return -ENOSYS;
 259     }
 260     if (assign) {
 261         /*
 262          * Stop using the generic ioeventfd, we are doing eventfd handling
 263          * ourselves below
 264          */
 265         k->ioeventfd_set_disabled(proxy, true);
 266     }
 267     /*
 268      * Just switch the handler, don't deassign the ioeventfd.
 269      * Otherwise, there's a window where we don't have an
 270      * ioeventfd and we may end up with a notification where
 271      * we don't expect one.
 272      */
 273     virtio_queue_set_host_notifier_fd_handler(vq, assign, !assign);
 274     if (!assign) {
 275         /* Use generic ioeventfd handler again. */
 276         k->ioeventfd_set_disabled(proxy, false);
 277     }
 278     return 0;
 279 }
 280
 281 static char *virtio_bus_get_dev_path(DeviceState *dev)
 282 {
 283     BusState *bus = qdev_get_parent_bus(dev);
 284     DeviceState *proxy = DEVICE(bus->parent);
 285     return qdev_get_dev_path(proxy);
 286 }
 287
 288 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
 289 {
 290     return NULL;
 291 }
 292
 293 static void virtio_bus_class_init(ObjectClass *klass, void *data)
 294 {
 295     BusClass *bus_class = BUS_CLASS(klass);
 296     bus_class->get_dev_path = virtio_bus_get_dev_path;
 297     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
 298 }
 299
 300 static const TypeInfo virtio_bus_info = {
 301     .name = TYPE_VIRTIO_BUS,
 302     .parent = TYPE_BUS,
 303     .instance_size = sizeof(VirtioBusState),
 304     .abstract = true,
 305     .class_size = sizeof(VirtioBusClass),
 306     .class_init = virtio_bus_class_init
 307 };
 308
 309 static void virtio_register_types(void)
 310 {
 311     type_register_static(&virtio_bus_info);
 312 }
 313
 314 type_init(virtio_register_types)