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