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->pre_plugged != NULL) {
  53         klass->pre_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
  61     if (klass->device_plugged != NULL) {
  62         klass->device_plugged(qbus->parent, errp);
  63     }
  64 }
  65
  66 /* Reset the virtio_bus */
  67 void virtio_bus_reset(VirtioBusState *bus)
  68 {
  69     VirtIODevice *vdev = virtio_bus_get_device(bus);
  70
  71     DPRINTF("%s: reset device.\n", BUS(bus)->name);
  72     if (vdev != NULL) {
  73         virtio_reset(vdev);
  74     }
  75 }
  76
  77 /* A VirtIODevice is being unplugged */
  78 void virtio_bus_device_unplugged(VirtIODevice *vdev)
  79 {
  80     DeviceState *qdev = DEVICE(vdev);
  81     BusState *qbus = BUS(qdev_get_parent_bus(qdev));
  82     VirtioBusClass *klass = VIRTIO_BUS_GET_CLASS(qbus);
  83
  84     DPRINTF("%s: remove device.\n", qbus->name);
  85
  86     if (vdev != NULL) {
  87         if (klass->device_unplugged != NULL) {
  88             klass->device_unplugged(qbus->parent);
  89         }
  90     }
  91 }
  92
  93 /* Get the device id of the plugged device. */
  94 uint16_t virtio_bus_get_vdev_id(VirtioBusState *bus)
  95 {
  96     VirtIODevice *vdev = virtio_bus_get_device(bus);
  97     assert(vdev != NULL);
  98     return vdev->device_id;
  99 }
 100
 101 /* Get the config_len field of the plugged device. */
 102 size_t virtio_bus_get_vdev_config_len(VirtioBusState *bus)
 103 {
 104     VirtIODevice *vdev = virtio_bus_get_device(bus);
 105     assert(vdev != NULL);
 106     return vdev->config_len;
 107 }
 108
 109 /* Get bad features of the plugged device. */
 110 uint32_t virtio_bus_get_vdev_bad_features(VirtioBusState *bus)
 111 {
 112     VirtIODevice *vdev = virtio_bus_get_device(bus);
 113     VirtioDeviceClass *k;
 114
 115     assert(vdev != NULL);
 116     k = VIRTIO_DEVICE_GET_CLASS(vdev);
 117     if (k->bad_features != NULL) {
 118         return k->bad_features(vdev);
 119     } else {
 120         return 0;
 121     }
 122 }
 123
 124 /* Get config of the plugged device. */
 125 void virtio_bus_get_vdev_config(VirtioBusState *bus, uint8_t *config)
 126 {
 127     VirtIODevice *vdev = virtio_bus_get_device(bus);
 128     VirtioDeviceClass *k;
 129
 130     assert(vdev != NULL);
 131     k = VIRTIO_DEVICE_GET_CLASS(vdev);
 132     if (k->get_config != NULL) {
 133         k->get_config(vdev, config);
 134     }
 135 }
 136
 137 /* Set config of the plugged device. */
 138 void virtio_bus_set_vdev_config(VirtioBusState *bus, uint8_t *config)
 139 {
 140     VirtIODevice *vdev = virtio_bus_get_device(bus);
 141     VirtioDeviceClass *k;
 142
 143     assert(vdev != NULL);
 144     k = VIRTIO_DEVICE_GET_CLASS(vdev);
 145     if (k->set_config != NULL) {
 146         k->set_config(vdev, config);
 147     }
 148 }
 149
 150 /*
 151  * This function handles both assigning the ioeventfd handler and
 152  * registering it with the kernel.
 153  * assign: register/deregister ioeventfd with the kernel
 154  * set_handler: use the generic ioeventfd handler
 155  */
 156 int set_host_notifier_internal(DeviceState *proxy, VirtioBusState *bus,
 157                                int n, bool assign, bool set_handler)
 158 {
 159     VirtIODevice *vdev = virtio_bus_get_device(bus);
 160     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 161     VirtQueue *vq = virtio_get_queue(vdev, n);
 162     EventNotifier *notifier = virtio_queue_get_host_notifier(vq);
 163     int r = 0;
 164
 165     if (assign) {
 166         r = event_notifier_init(notifier, 1);
 167         if (r < 0) {
 168             error_report("%s: unable to init event notifier: %s (%d)",
 169                          __func__, strerror(-r), r);
 170             return r;
 171         }
 172         virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler);
 173         r = k->ioeventfd_assign(proxy, notifier, n, assign);
 174         if (r < 0) {
 175             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
 176             virtio_queue_set_host_notifier_fd_handler(vq, false, false);
 177             event_notifier_cleanup(notifier);
 178             return r;
 179         }
 180     } else {
 181         k->ioeventfd_assign(proxy, notifier, n, assign);
 182         virtio_queue_set_host_notifier_fd_handler(vq, false, false);
 183         event_notifier_cleanup(notifier);
 184     }
 185     return r;
 186 }
 187
 188 int virtio_bus_start_ioeventfd(VirtioBusState *bus)
 189 {
 190     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 191     DeviceState *proxy = DEVICE(BUS(bus)->parent);
 192     VirtIODevice *vdev = virtio_bus_get_device(bus);
 193     VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
 194     int r;
 195
 196     if (!k->ioeventfd_assign || k->ioeventfd_disabled(proxy)) {
 197         return -ENOSYS;
 198     }
 199     if (bus->ioeventfd_started || bus->ioeventfd_disabled) {
 200         return 0;
 201     }
 202     r = vdc->start_ioeventfd(vdev);
 203     if (r < 0) {
 204         error_report("%s: failed. Fallback to userspace (slower).", __func__);
 205         return r;
 206     }
 207     bus->ioeventfd_started = true;
 208     return 0;
 209 }
 210
 211 void virtio_bus_stop_ioeventfd(VirtioBusState *bus)
 212 {
 213     VirtIODevice *vdev;
 214     VirtioDeviceClass *vdc;
 215
 216     if (!bus->ioeventfd_started) {
 217         return;
 218     }
 219
 220     vdev = virtio_bus_get_device(bus);
 221     vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
 222     vdc->stop_ioeventfd(vdev);
 223     bus->ioeventfd_started = false;
 224 }
 225
 226 /*
 227  * This function switches from/to the generic ioeventfd handler.
 228  * assign==false means 'use generic ioeventfd handler'.
 229  */
 230 int virtio_bus_set_host_notifier(VirtioBusState *bus, int n, bool assign)
 231 {
 232     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(bus);
 233     DeviceState *proxy = DEVICE(BUS(bus)->parent);
 234
 235     if (!k->ioeventfd_assign) {
 236         return -ENOSYS;
 237     }
 238     bus->ioeventfd_disabled = assign;
 239     if (assign) {
 240         /*
 241          * Stop using the generic ioeventfd, we are doing eventfd handling
 242          * ourselves below
 243          *
 244          * FIXME: We should just switch the handler and not deassign the
 245          * ioeventfd.
 246          * Otherwise, there's a window where we don't have an
 247          * ioeventfd and we may end up with a notification where
 248          * we don't expect one.
 249          */
 250         virtio_bus_stop_ioeventfd(bus);
 251     }
 252     return set_host_notifier_internal(proxy, bus, n, assign, false);
 253 }
 254
 255 static char *virtio_bus_get_dev_path(DeviceState *dev)
 256 {
 257     BusState *bus = qdev_get_parent_bus(dev);
 258     DeviceState *proxy = DEVICE(bus->parent);
 259     return qdev_get_dev_path(proxy);
 260 }
 261
 262 static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
 263 {
 264     return NULL;
 265 }
 266
 267 static void virtio_bus_class_init(ObjectClass *klass, void *data)
 268 {
 269     BusClass *bus_class = BUS_CLASS(klass);
 270     bus_class->get_dev_path = virtio_bus_get_dev_path;
 271     bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
 272 }
 273
 274 static const TypeInfo virtio_bus_info = {
 275     .name = TYPE_VIRTIO_BUS,
 276     .parent = TYPE_BUS,
 277     .instance_size = sizeof(VirtioBusState),
 278     .abstract = true,
 279     .class_size = sizeof(VirtioBusClass),
 280     .class_init = virtio_bus_class_init
 281 };
 282
 283 static void virtio_register_types(void)
 284 {
 285     type_register_static(&virtio_bus_info);
 286 }
 287
 288 type_init(virtio_register_types)