hw/virtio/vhost-user-i2c.c

   1 /*
   2  * Vhost-user i2c virtio device
   3  *
   4  * Copyright (c) 2021 Viresh Kumar <viresh.kumar@linaro.org>
   5  *
   6  * SPDX-License-Identifier: GPL-2.0-or-later
   7  */
   8
   9 #include "qemu/osdep.h"
  10 #include "qapi/error.h"
  11 #include "hw/qdev-properties.h"
  12 #include "hw/virtio/virtio-bus.h"
  13 #include "hw/virtio/vhost-user-i2c.h"
  14 #include "qemu/error-report.h"
  15 #include "standard-headers/linux/virtio_ids.h"
  16
  17 static const int feature_bits[] = {
  18     VIRTIO_I2C_F_ZERO_LENGTH_REQUEST,
  19     VIRTIO_F_RING_RESET,
  20     VHOST_INVALID_FEATURE_BIT
  21 };
  22
  23 static void vu_i2c_start(VirtIODevice *vdev)
  24 {
  25     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
  26     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
  27     VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
  28     int ret, i;
  29
  30     if (!k->set_guest_notifiers) {
  31         error_report("binding does not support guest notifiers");
  32         return;
  33     }
  34
  35     ret = vhost_dev_enable_notifiers(&i2c->vhost_dev, vdev);
  36     if (ret < 0) {
  37         error_report("Error enabling host notifiers: %d", -ret);
  38         return;
  39     }
  40
  41     ret = k->set_guest_notifiers(qbus->parent, i2c->vhost_dev.nvqs, true);
  42     if (ret < 0) {
  43         error_report("Error binding guest notifier: %d", -ret);
  44         goto err_host_notifiers;
  45     }
  46
  47     i2c->vhost_dev.acked_features = vdev->guest_features;
  48
  49     ret = vhost_dev_start(&i2c->vhost_dev, vdev, true);
  50     if (ret < 0) {
  51         error_report("Error starting vhost-user-i2c: %d", -ret);
  52         goto err_guest_notifiers;
  53     }
  54
  55     /*
  56      * guest_notifier_mask/pending not used yet, so just unmask
  57      * everything here. virtio-pci will do the right thing by
  58      * enabling/disabling irqfd.
  59      */
  60     for (i = 0; i < i2c->vhost_dev.nvqs; i++) {
  61         vhost_virtqueue_mask(&i2c->vhost_dev, vdev, i, false);
  62     }
  63
  64     return;
  65
  66 err_guest_notifiers:
  67     k->set_guest_notifiers(qbus->parent, i2c->vhost_dev.nvqs, false);
  68 err_host_notifiers:
  69     vhost_dev_disable_notifiers(&i2c->vhost_dev, vdev);
  70 }
  71
  72 static void vu_i2c_stop(VirtIODevice *vdev)
  73 {
  74     VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
  75     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
  76     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
  77     int ret;
  78
  79     if (!k->set_guest_notifiers) {
  80         return;
  81     }
  82
  83     vhost_dev_stop(&i2c->vhost_dev, vdev, true);
  84
  85     ret = k->set_guest_notifiers(qbus->parent, i2c->vhost_dev.nvqs, false);
  86     if (ret < 0) {
  87         error_report("vhost guest notifier cleanup failed: %d", ret);
  88         return;
  89     }
  90
  91     vhost_dev_disable_notifiers(&i2c->vhost_dev, vdev);
  92 }
  93
  94 static void vu_i2c_set_status(VirtIODevice *vdev, uint8_t status)
  95 {
  96     VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
  97     bool should_start = virtio_device_should_start(vdev, status);
  98
  99     if (vhost_dev_is_started(&i2c->vhost_dev) == should_start) {
 100         return;
 101     }
 102
 103     if (should_start) {
 104         vu_i2c_start(vdev);
 105     } else {
 106         vu_i2c_stop(vdev);
 107     }
 108 }
 109
 110 static uint64_t vu_i2c_get_features(VirtIODevice *vdev,
 111                                     uint64_t requested_features, Error **errp)
 112 {
 113     VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
 114
 115     virtio_add_feature(&requested_features, VIRTIO_I2C_F_ZERO_LENGTH_REQUEST);
 116     return vhost_get_features(&i2c->vhost_dev, feature_bits, requested_features);
 117 }
 118
 119 static void vu_i2c_handle_output(VirtIODevice *vdev, VirtQueue *vq)
 120 {
 121     /*
 122      * Not normally called; it's the daemon that handles the queue;
 123      * however virtio's cleanup path can call this.
 124      */
 125 }
 126
 127 static void vu_i2c_guest_notifier_mask(VirtIODevice *vdev, int idx, bool mask)
 128 {
 129     VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
 130
 131     /*
 132      * We don't support interrupts, return early if index is set to
 133      * VIRTIO_CONFIG_IRQ_IDX.
 134      */
 135     if (idx == VIRTIO_CONFIG_IRQ_IDX) {
 136         return;
 137     }
 138
 139     vhost_virtqueue_mask(&i2c->vhost_dev, vdev, idx, mask);
 140 }
 141
 142 static bool vu_i2c_guest_notifier_pending(VirtIODevice *vdev, int idx)
 143 {
 144     VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
 145
 146     /*
 147      * We don't support interrupts, return early if index is set to
 148      * VIRTIO_CONFIG_IRQ_IDX.
 149      */
 150     if (idx == VIRTIO_CONFIG_IRQ_IDX) {
 151         return false;
 152     }
 153
 154     return vhost_virtqueue_pending(&i2c->vhost_dev, idx);
 155 }
 156
 157 static void do_vhost_user_cleanup(VirtIODevice *vdev, VHostUserI2C *i2c)
 158 {
 159     vhost_user_cleanup(&i2c->vhost_user);
 160     virtio_delete_queue(i2c->vq);
 161     virtio_cleanup(vdev);
 162 }
 163
 164 static int vu_i2c_connect(DeviceState *dev)
 165 {
 166     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 167     VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
 168
 169     if (i2c->connected) {
 170         return 0;
 171     }
 172     i2c->connected = true;
 173
 174     /* restore vhost state */
 175     if (virtio_device_started(vdev, vdev->status)) {
 176         vu_i2c_start(vdev);
 177     }
 178
 179     return 0;
 180 }
 181
 182 static void vu_i2c_disconnect(DeviceState *dev)
 183 {
 184     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 185     VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
 186
 187     if (!i2c->connected) {
 188         return;
 189     }
 190     i2c->connected = false;
 191
 192     if (vhost_dev_is_started(&i2c->vhost_dev)) {
 193         vu_i2c_stop(vdev);
 194     }
 195 }
 196
 197 static void vu_i2c_event(void *opaque, QEMUChrEvent event)
 198 {
 199     DeviceState *dev = opaque;
 200     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 201     VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
 202
 203     switch (event) {
 204     case CHR_EVENT_OPENED:
 205         if (vu_i2c_connect(dev) < 0) {
 206             qemu_chr_fe_disconnect(&i2c->chardev);
 207             return;
 208         }
 209         break;
 210     case CHR_EVENT_CLOSED:
 211         vu_i2c_disconnect(dev);
 212         break;
 213     case CHR_EVENT_BREAK:
 214     case CHR_EVENT_MUX_IN:
 215     case CHR_EVENT_MUX_OUT:
 216         /* Ignore */
 217         break;
 218     }
 219 }
 220
 221 static void vu_i2c_device_realize(DeviceState *dev, Error **errp)
 222 {
 223     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 224     VHostUserI2C *i2c = VHOST_USER_I2C(dev);
 225     int ret;
 226
 227     if (!i2c->chardev.chr) {
 228         error_setg(errp, "vhost-user-i2c: missing chardev");
 229         return;
 230     }
 231
 232     if (!vhost_user_init(&i2c->vhost_user, &i2c->chardev, errp)) {
 233         return;
 234     }
 235
 236     virtio_init(vdev, VIRTIO_ID_I2C_ADAPTER, 0);
 237
 238     i2c->vhost_dev.nvqs = 1;
 239     i2c->vq = virtio_add_queue(vdev, 4, vu_i2c_handle_output);
 240     i2c->vhost_dev.vqs = g_new0(struct vhost_virtqueue, i2c->vhost_dev.nvqs);
 241
 242     ret = vhost_dev_init(&i2c->vhost_dev, &i2c->vhost_user,
 243                          VHOST_BACKEND_TYPE_USER, 0, errp);
 244     if (ret < 0) {
 245         g_free(i2c->vhost_dev.vqs);
 246         do_vhost_user_cleanup(vdev, i2c);
 247     }
 248
 249     qemu_chr_fe_set_handlers(&i2c->chardev, NULL, NULL, vu_i2c_event, NULL,
 250                              dev, NULL, true);
 251 }
 252
 253 static void vu_i2c_device_unrealize(DeviceState *dev)
 254 {
 255     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
 256     VHostUserI2C *i2c = VHOST_USER_I2C(dev);
 257     struct vhost_virtqueue *vhost_vqs = i2c->vhost_dev.vqs;
 258
 259     /* This will stop vhost backend if appropriate. */
 260     vu_i2c_set_status(vdev, 0);
 261     vhost_dev_cleanup(&i2c->vhost_dev);
 262     g_free(vhost_vqs);
 263     do_vhost_user_cleanup(vdev, i2c);
 264 }
 265
 266 static const VMStateDescription vu_i2c_vmstate = {
 267     .name = "vhost-user-i2c",
 268     .unmigratable = 1,
 269 };
 270
 271 static Property vu_i2c_properties[] = {
 272     DEFINE_PROP_CHR("chardev", VHostUserI2C, chardev),
 273     DEFINE_PROP_END_OF_LIST(),
 274 };
 275
 276 static void vu_i2c_class_init(ObjectClass *klass, void *data)
 277 {
 278     DeviceClass *dc = DEVICE_CLASS(klass);
 279     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 280
 281     device_class_set_props(dc, vu_i2c_properties);
 282     dc->vmsd = &vu_i2c_vmstate;
 283     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
 284     vdc->realize = vu_i2c_device_realize;
 285     vdc->unrealize = vu_i2c_device_unrealize;
 286     vdc->get_features = vu_i2c_get_features;
 287     vdc->set_status = vu_i2c_set_status;
 288     vdc->guest_notifier_mask = vu_i2c_guest_notifier_mask;
 289     vdc->guest_notifier_pending = vu_i2c_guest_notifier_pending;
 290 }
 291
 292 static const TypeInfo vu_i2c_info = {
 293     .name = TYPE_VHOST_USER_I2C,
 294     .parent = TYPE_VIRTIO_DEVICE,
 295     .instance_size = sizeof(VHostUserI2C),
 296     .class_init = vu_i2c_class_init,
 297 };
 298
 299 static void vu_i2c_register_types(void)
 300 {
 301     type_register_static(&vu_i2c_info);
 302 }
 303
 304 type_init(vu_i2c_register_types)