LXR qemu/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, ...) \
  36do { 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 */
  42void 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 */
  66void 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 */
  77void 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. */
  93uint16_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. */
 101size_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. */
 109uint32_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. */
 124void 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. */
 137void 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 */
 155static 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        k->ioeventfd_assign(proxy, notifier, n, assign);
 180        virtio_queue_set_host_notifier_fd_handler(vq, false, false);
 181        event_notifier_cleanup(notifier);
 182    }
 183    return r;
 184}
 185
 186void 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
 212assign_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
 225void 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 */
 250int 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
 255    if (!k->ioeventfd_started) {
 256        return -ENOSYS;
 257    }
 258    k->ioeventfd_set_disabled(proxy, assign);
 259    if (assign) {
 260        /*
 261         * Stop using the generic ioeventfd, we are doing eventfd handling
 262         * ourselves below
 263         *
 264         * FIXME: We should just switch the handler and not deassign the
 265         * ioeventfd.
 266         * Otherwise, there's a window where we don't have an
 267         * ioeventfd and we may end up with a notification where
 268         * we don't expect one.
 269         */
 270        virtio_bus_stop_ioeventfd(bus);
 271    }
 272    return set_host_notifier_internal(proxy, bus, n, assign, false);
 273}
 274
 275static char *virtio_bus_get_dev_path(DeviceState *dev)
 276{
 277    BusState *bus = qdev_get_parent_bus(dev);
 278    DeviceState *proxy = DEVICE(bus->parent);
 279    return qdev_get_dev_path(proxy);
 280}
 281
 282static char *virtio_bus_get_fw_dev_path(DeviceState *dev)
 283{
 284    return NULL;
 285}
 286
 287static void virtio_bus_class_init(ObjectClass *klass, void *data)
 288{
 289    BusClass *bus_class = BUS_CLASS(klass);
 290    bus_class->get_dev_path = virtio_bus_get_dev_path;
 291    bus_class->get_fw_dev_path = virtio_bus_get_fw_dev_path;
 292}
 293
 294static const TypeInfo virtio_bus_info = {
 295    .name = TYPE_VIRTIO_BUS,
 296    .parent = TYPE_BUS,
 297    .instance_size = sizeof(VirtioBusState),
 298    .abstract = true,
 299    .class_size = sizeof(VirtioBusClass),
 300    .class_init = virtio_bus_class_init
 301};
 302
 303static void virtio_register_types(void)
 304{
 305    type_register_static(&virtio_bus_info);
 306}
 307
 308type_init(virtio_register_types)
 309