1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (c) 2013, Microsoft Corporation. 4 */ 5 6 #include <linux/init.h> 7 #include <linux/module.h> 8 #include <linux/device.h> 9 #include <linux/completion.h> 10 #include <linux/hyperv.h> 11 #include <linux/serio.h> 12 #include <linux/slab.h> 13 14 /* 15 * Current version 1.0 16 * 17 */ 18 #define SYNTH_KBD_VERSION_MAJOR 1 19 #define SYNTH_KBD_VERSION_MINOR 0 20 #define SYNTH_KBD_VERSION (SYNTH_KBD_VERSION_MINOR | \ 21 (SYNTH_KBD_VERSION_MAJOR << 16)) 22 23 24 /* 25 * Message types in the synthetic input protocol 26 */ 27 enum synth_kbd_msg_type { 28 SYNTH_KBD_PROTOCOL_REQUEST = 1, 29 SYNTH_KBD_PROTOCOL_RESPONSE = 2, 30 SYNTH_KBD_EVENT = 3, 31 SYNTH_KBD_LED_INDICATORS = 4, 32 }; 33 34 /* 35 * Basic message structures. 36 */ 37 struct synth_kbd_msg_hdr { 38 __le32 type; 39 }; 40 41 struct synth_kbd_msg { 42 struct synth_kbd_msg_hdr header; 43 char data[]; /* Enclosed message */ 44 }; 45 46 union synth_kbd_version { 47 __le32 version; 48 }; 49 50 /* 51 * Protocol messages 52 */ 53 struct synth_kbd_protocol_request { 54 struct synth_kbd_msg_hdr header; 55 union synth_kbd_version version_requested; 56 }; 57 58 #define PROTOCOL_ACCEPTED BIT(0) 59 struct synth_kbd_protocol_response { 60 struct synth_kbd_msg_hdr header; 61 __le32 proto_status; 62 }; 63 64 #define IS_UNICODE BIT(0) 65 #define IS_BREAK BIT(1) 66 #define IS_E0 BIT(2) 67 #define IS_E1 BIT(3) 68 struct synth_kbd_keystroke { 69 struct synth_kbd_msg_hdr header; 70 __le16 make_code; 71 __le16 reserved0; 72 __le32 info; /* Additional information */ 73 }; 74 75 76 #define HK_MAXIMUM_MESSAGE_SIZE 256 77 78 #define KBD_VSC_SEND_RING_BUFFER_SIZE VMBUS_RING_SIZE(36 * 1024) 79 #define KBD_VSC_RECV_RING_BUFFER_SIZE VMBUS_RING_SIZE(36 * 1024) 80 81 #define XTKBD_EMUL0 0xe0 82 #define XTKBD_EMUL1 0xe1 83 #define XTKBD_RELEASE 0x80 84 85 86 /* 87 * Represents a keyboard device 88 */ 89 struct hv_kbd_dev { 90 struct hv_device *hv_dev; 91 struct serio *hv_serio; 92 struct synth_kbd_protocol_request protocol_req; 93 struct synth_kbd_protocol_response protocol_resp; 94 /* Synchronize the request/response if needed */ 95 struct completion wait_event; 96 spinlock_t lock; /* protects 'started' field */ 97 bool started; 98 }; 99 100 static void hv_kbd_on_receive(struct hv_device *hv_dev, 101 struct synth_kbd_msg *msg, u32 msg_length) 102 { 103 struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev); 104 struct synth_kbd_keystroke *ks_msg; 105 unsigned long flags; 106 u32 msg_type = __le32_to_cpu(msg->header.type); 107 u32 info; 108 u16 scan_code; 109 110 switch (msg_type) { 111 case SYNTH_KBD_PROTOCOL_RESPONSE: 112 /* 113 * Validate the information provided by the host. 114 * If the host is giving us a bogus packet, 115 * drop the packet (hoping the problem 116 * goes away). 117 */ 118 if (msg_length < sizeof(struct synth_kbd_protocol_response)) { 119 dev_err(&hv_dev->device, 120 "Illegal protocol response packet (len: %d)\n", 121 msg_length); 122 break; 123 } 124 125 memcpy(&kbd_dev->protocol_resp, msg, 126 sizeof(struct synth_kbd_protocol_response)); 127 complete(&kbd_dev->wait_event); 128 break; 129 130 case SYNTH_KBD_EVENT: 131 /* 132 * Validate the information provided by the host. 133 * If the host is giving us a bogus packet, 134 * drop the packet (hoping the problem 135 * goes away). 136 */ 137 if (msg_length < sizeof(struct synth_kbd_keystroke)) { 138 dev_err(&hv_dev->device, 139 "Illegal keyboard event packet (len: %d)\n", 140 msg_length); 141 break; 142 } 143 144 ks_msg = (struct synth_kbd_keystroke *)msg; 145 info = __le32_to_cpu(ks_msg->info); 146 147 /* 148 * Inject the information through the serio interrupt. 149 */ 150 spin_lock_irqsave(&kbd_dev->lock, flags); 151 if (kbd_dev->started) { 152 if (info & IS_E0) 153 serio_interrupt(kbd_dev->hv_serio, 154 XTKBD_EMUL0, 0); 155 if (info & IS_E1) 156 serio_interrupt(kbd_dev->hv_serio, 157 XTKBD_EMUL1, 0); 158 scan_code = __le16_to_cpu(ks_msg->make_code); 159 if (info & IS_BREAK) 160 scan_code |= XTKBD_RELEASE; 161 162 serio_interrupt(kbd_dev->hv_serio, scan_code, 0); 163 } 164 spin_unlock_irqrestore(&kbd_dev->lock, flags); 165 166 /* 167 * Only trigger a wakeup on key down, otherwise 168 * "echo freeze > /sys/power/state" can't really enter the 169 * state because the Enter-UP can trigger a wakeup at once. 170 */ 171 if (!(info & IS_BREAK)) 172 pm_wakeup_hard_event(&hv_dev->device); 173 174 break; 175 176 default: 177 dev_err(&hv_dev->device, 178 "unhandled message type %d\n", msg_type); 179 } 180 } 181 182 static void hv_kbd_handle_received_packet(struct hv_device *hv_dev, 183 struct vmpacket_descriptor *desc, 184 u32 bytes_recvd, 185 u64 req_id) 186 { 187 struct synth_kbd_msg *msg; 188 u32 msg_sz; 189 190 switch (desc->type) { 191 case VM_PKT_COMP: 192 break; 193 194 case VM_PKT_DATA_INBAND: 195 /* 196 * We have a packet that has "inband" data. The API used 197 * for retrieving the packet guarantees that the complete 198 * packet is read. So, minimally, we should be able to 199 * parse the payload header safely (assuming that the host 200 * can be trusted. Trusting the host seems to be a 201 * reasonable assumption because in a virtualized 202 * environment there is not whole lot you can do if you 203 * don't trust the host. 204 * 205 * Nonetheless, let us validate if the host can be trusted 206 * (in a trivial way). The interesting aspect of this 207 * validation is how do you recover if we discover that the 208 * host is not to be trusted? Simply dropping the packet, I 209 * don't think is an appropriate recovery. In the interest 210 * of failing fast, it may be better to crash the guest. 211 * For now, I will just drop the packet! 212 */ 213 214 msg_sz = bytes_recvd - (desc->offset8 << 3); 215 if (msg_sz <= sizeof(struct synth_kbd_msg_hdr)) { 216 /* 217 * Drop the packet and hope 218 * the problem magically goes away. 219 */ 220 dev_err(&hv_dev->device, 221 "Illegal packet (type: %d, tid: %llx, size: %d)\n", 222 desc->type, req_id, msg_sz); 223 break; 224 } 225 226 msg = (void *)desc + (desc->offset8 << 3); 227 hv_kbd_on_receive(hv_dev, msg, msg_sz); 228 break; 229 230 default: 231 dev_err(&hv_dev->device, 232 "unhandled packet type %d, tid %llx len %d\n", 233 desc->type, req_id, bytes_recvd); 234 break; 235 } 236 } 237 238 static void hv_kbd_on_channel_callback(void *context) 239 { 240 struct vmpacket_descriptor *desc; 241 struct hv_device *hv_dev = context; 242 u32 bytes_recvd; 243 u64 req_id; 244 245 foreach_vmbus_pkt(desc, hv_dev->channel) { 246 bytes_recvd = desc->len8 * 8; 247 req_id = desc->trans_id; 248 249 hv_kbd_handle_received_packet(hv_dev, desc, bytes_recvd, 250 req_id); 251 } 252 } 253 254 static int hv_kbd_connect_to_vsp(struct hv_device *hv_dev) 255 { 256 struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev); 257 struct synth_kbd_protocol_request *request; 258 struct synth_kbd_protocol_response *response; 259 u32 proto_status; 260 int error; 261 262 reinit_completion(&kbd_dev->wait_event); 263 264 request = &kbd_dev->protocol_req; 265 memset(request, 0, sizeof(struct synth_kbd_protocol_request)); 266 request->header.type = __cpu_to_le32(SYNTH_KBD_PROTOCOL_REQUEST); 267 request->version_requested.version = __cpu_to_le32(SYNTH_KBD_VERSION); 268 269 error = vmbus_sendpacket(hv_dev->channel, request, 270 sizeof(struct synth_kbd_protocol_request), 271 (unsigned long)request, 272 VM_PKT_DATA_INBAND, 273 VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); 274 if (error) 275 return error; 276 277 if (!wait_for_completion_timeout(&kbd_dev->wait_event, 10 * HZ)) 278 return -ETIMEDOUT; 279 280 response = &kbd_dev->protocol_resp; 281 proto_status = __le32_to_cpu(response->proto_status); 282 if (!(proto_status & PROTOCOL_ACCEPTED)) { 283 dev_err(&hv_dev->device, 284 "synth_kbd protocol request failed (version %d)\n", 285 SYNTH_KBD_VERSION); 286 return -ENODEV; 287 } 288 289 return 0; 290 } 291 292 static int hv_kbd_start(struct serio *serio) 293 { 294 struct hv_kbd_dev *kbd_dev = serio->port_data; 295 unsigned long flags; 296 297 spin_lock_irqsave(&kbd_dev->lock, flags); 298 kbd_dev->started = true; 299 spin_unlock_irqrestore(&kbd_dev->lock, flags); 300 301 return 0; 302 } 303 304 static void hv_kbd_stop(struct serio *serio) 305 { 306 struct hv_kbd_dev *kbd_dev = serio->port_data; 307 unsigned long flags; 308 309 spin_lock_irqsave(&kbd_dev->lock, flags); 310 kbd_dev->started = false; 311 spin_unlock_irqrestore(&kbd_dev->lock, flags); 312 } 313 314 static int hv_kbd_probe(struct hv_device *hv_dev, 315 const struct hv_vmbus_device_id *dev_id) 316 { 317 struct hv_kbd_dev *kbd_dev; 318 struct serio *hv_serio; 319 int error; 320 321 kbd_dev = kzalloc(sizeof(struct hv_kbd_dev), GFP_KERNEL); 322 hv_serio = kzalloc(sizeof(struct serio), GFP_KERNEL); 323 if (!kbd_dev || !hv_serio) { 324 error = -ENOMEM; 325 goto err_free_mem; 326 } 327 328 kbd_dev->hv_dev = hv_dev; 329 kbd_dev->hv_serio = hv_serio; 330 spin_lock_init(&kbd_dev->lock); 331 init_completion(&kbd_dev->wait_event); 332 hv_set_drvdata(hv_dev, kbd_dev); 333 334 hv_serio->dev.parent = &hv_dev->device; 335 hv_serio->id.type = SERIO_8042_XL; 336 hv_serio->port_data = kbd_dev; 337 strscpy(hv_serio->name, dev_name(&hv_dev->device), 338 sizeof(hv_serio->name)); 339 strscpy(hv_serio->phys, dev_name(&hv_dev->device), 340 sizeof(hv_serio->phys)); 341 342 hv_serio->start = hv_kbd_start; 343 hv_serio->stop = hv_kbd_stop; 344 345 error = vmbus_open(hv_dev->channel, 346 KBD_VSC_SEND_RING_BUFFER_SIZE, 347 KBD_VSC_RECV_RING_BUFFER_SIZE, 348 NULL, 0, 349 hv_kbd_on_channel_callback, 350 hv_dev); 351 if (error) 352 goto err_free_mem; 353 354 error = hv_kbd_connect_to_vsp(hv_dev); 355 if (error) 356 goto err_close_vmbus; 357 358 serio_register_port(kbd_dev->hv_serio); 359 360 device_init_wakeup(&hv_dev->device, true); 361 362 return 0; 363 364 err_close_vmbus: 365 vmbus_close(hv_dev->channel); 366 err_free_mem: 367 kfree(hv_serio); 368 kfree(kbd_dev); 369 return error; 370 } 371 372 static int hv_kbd_remove(struct hv_device *hv_dev) 373 { 374 struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev); 375 376 serio_unregister_port(kbd_dev->hv_serio); 377 vmbus_close(hv_dev->channel); 378 kfree(kbd_dev); 379 380 hv_set_drvdata(hv_dev, NULL); 381 382 return 0; 383 } 384 385 static int hv_kbd_suspend(struct hv_device *hv_dev) 386 { 387 vmbus_close(hv_dev->channel); 388 389 return 0; 390 } 391 392 static int hv_kbd_resume(struct hv_device *hv_dev) 393 { 394 int ret; 395 396 ret = vmbus_open(hv_dev->channel, 397 KBD_VSC_SEND_RING_BUFFER_SIZE, 398 KBD_VSC_RECV_RING_BUFFER_SIZE, 399 NULL, 0, 400 hv_kbd_on_channel_callback, 401 hv_dev); 402 if (ret == 0) 403 ret = hv_kbd_connect_to_vsp(hv_dev); 404 405 return ret; 406 } 407 408 static const struct hv_vmbus_device_id id_table[] = { 409 /* Keyboard guid */ 410 { HV_KBD_GUID, }, 411 { }, 412 }; 413 414 MODULE_DEVICE_TABLE(vmbus, id_table); 415 416 static struct hv_driver hv_kbd_drv = { 417 .name = KBUILD_MODNAME, 418 .id_table = id_table, 419 .probe = hv_kbd_probe, 420 .remove = hv_kbd_remove, 421 .suspend = hv_kbd_suspend, 422 .resume = hv_kbd_resume, 423 .driver = { 424 .probe_type = PROBE_PREFER_ASYNCHRONOUS, 425 }, 426 }; 427 428 static int __init hv_kbd_init(void) 429 { 430 return vmbus_driver_register(&hv_kbd_drv); 431 } 432 433 static void __exit hv_kbd_exit(void) 434 { 435 vmbus_driver_unregister(&hv_kbd_drv); 436 } 437 438 MODULE_LICENSE("GPL"); 439 MODULE_DESCRIPTION("Microsoft Hyper-V Synthetic Keyboard Driver"); 440 441 module_init(hv_kbd_init); 442 module_exit(hv_kbd_exit); 443