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: %s (%d)",
 168                          __func__, strerror(-r), r);
 169             return r;
 170         }
 171         virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler);
 172         r = k->ioeventfd_assign(proxy, notifier, n, assign);
 173         if (r < 0) {
 174             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
 175             virtio_queue_set_host_notifier_fd_handler(vq, false, false);
 176             event_notifier_cleanup(notifier);
 177             return r;
 178         }
 179     } else {
 180         k->ioeventfd_assign(proxy, notifier, n, assign);
 181         virtio_queue_set_host_notifier_fd_handler(vq, false, false);
 182         event_notifier_cleanup(notifier);
 183     }
 184     return r;
 185 }
 186
 187 void virtio_bus_start_ioeventfd(VirtioBusState *bus)
 188 {
 189     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 190     DeviceState *proxy = DEVICE(BUS(bus)->parent);
 191     VirtIODevice *vdev;
 192     int n, r;
 193
 194     if (!k->ioeventfd_started || k->ioeventfd_started(proxy)) {
 195         return;
 196     }
 197     if (k->ioeventfd_disabled(proxy)) {
 198         return;
 199     }
 200     vdev = virtio_bus_get_device(bus);
 201     for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
 202         if (!virtio_queue_get_num(vdev, n)) {
 203             continue;
 204         }
 205         r = set_host_notifier_internal(proxy, bus, n, true, true);
 206         if (r < 0) {
 207             goto assign_error;
 208         }
 209     }
 210     k->ioeventfd_set_started(proxy, true, false);
 211     return;
 212
 213 assign_error:
 214     while (--n >= 0) {
 215         if (!virtio_queue_get_num(vdev, n)) {
 216             continue;
 217         }
 218
 219         r = set_host_notifier_internal(proxy, bus, n, false, false);
 220         assert(r >= 0);
 221     }
 222     k->ioeventfd_set_started(proxy, false, true);
 223     error_report("%s: failed. Fallback to userspace (slower).", __func__);
 224 }
 225
 226 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
 227 {
 228     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 229     DeviceState *proxy = DEVICE(BUS(bus)->parent);
 230     VirtIODevice *vdev;
 231     int n, r;
 232
 233     if (!k->ioeventfd_started || !k->ioeventfd_started(proxy)) {
 234         return;
 235     }
 236     vdev = virtio_bus_get_device(bus);
 237     for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
 238         if (!virtio_queue_get_num(vdev, n)) {
 239             continue;
 240         }
 241         r = set_host_notifier_internal(proxy, bus, n, false, false);
 242         assert(r >= 0);
 243     }
 244     k->ioeventfd_set_started(proxy, false, false);
 245 }
 246
 247 /*
 248  * This function switches from/to the generic ioeventfd handler.
 249  * assign==false means 'use generic ioeventfd handler'.
 250  */
 251 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
 252 {
 253     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 254     DeviceState *proxy = DEVICE(BUS(bus)->parent);
 255
 256     if (!k->ioeventfd_started) {
 257         return -ENOSYS;
 258     }
 259     k->ioeventfd_set_disabled(proxy, assign);
 260     if (assign) {
 261         /*
 262          * Stop using the generic ioeventfd, we are doing eventfd handling
 263          * ourselves below
 264          *
 265          * FIXME: We should just switch the handler and not deassign the
 266          * ioeventfd.
 267          * Otherwise, there's a window where we don't have an
 268          * ioeventfd and we may end up with a notification where
 269          * we don't expect one.
 270          */
 271         virtio_bus_stop_ioeventfd(bus);
 272     }
 273     return set_host_notifier_internal(proxy, bus, n, assign, false);
 274 }
 275
 276 static char *virtio_bus_get_dev_path(DeviceState *dev)
 277 {
 278     BusState *bus = qdev_get_parent_bus(dev);
 279     DeviceState *proxy = DEVICE(bus->parent);
 280     return qdev_get_dev_path(proxy);
 281 }
 282
 283 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
 284 {
 285     return NULL;
 286 }
 287
 288 static void virtio_bus_class_init(ObjectClass *klass, void *data)
 289 {
 290     BusClass *bus_class = BUS_CLASS(klass);
 291     bus_class->get_dev_path = virtio_bus_get_dev_path;
 292     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
 293 }
 294
 295 static const TypeInfo virtio_bus_info = {
 296     .name = TYPE_VIRTIO_BUS,
 297     .parent = TYPE_BUS,
 298     .instance_size = sizeof(VirtioBusState),
 299     .abstract = true,
 300     .class_size = sizeof(VirtioBusClass),
 301     .class_init = virtio_bus_class_init
 302 };
 303
 304 static void virtio_register_types(void)
 305 {
 306     type_register_static(&virtio_bus_info);
 307 }
 308
 309 type_init(virtio_register_types)