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 */
27enum 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 */
37struct synth_kbd_msg_hdr {
38 __le32 type;
39};
40
41struct synth_kbd_msg {
42 struct synth_kbd_msg_hdr header;
43 char data[]; /* Enclosed message */
44};
45
46union synth_kbd_version {
47 __le32 version;
48};
49
50/*
51 * Protocol messages
52 */
53struct 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)
59struct 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)
68struct 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 */
89struct 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
100static 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(dev: 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(serio: kbd_dev->hv_serio,
154 XTKBD_EMUL0, flags: 0);
155 if (info & IS_E1)
156 serio_interrupt(serio: kbd_dev->hv_serio,
157 XTKBD_EMUL1, flags: 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(serio: kbd_dev->hv_serio, data: scan_code, flags: 0);
163 }
164 spin_unlock_irqrestore(lock: &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(dev: &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
182static 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_length: 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
238static 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
254static int hv_kbd_connect_to_vsp(struct hv_device *hv_dev)
255{
256 struct hv_kbd_dev *kbd_dev = hv_get_drvdata(dev: 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(x: &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(channel: hv_dev->channel, buffer: request,
270 bufferLen: sizeof(struct synth_kbd_protocol_request),
271 requestid: (unsigned long)request,
272 type: VM_PKT_DATA_INBAND,
273 VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
274 if (error)
275 return error;
276
277 if (!wait_for_completion_timeout(x: &kbd_dev->wait_event, timeout: 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
292static 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(lock: &kbd_dev->lock, flags);
300
301 return 0;
302}
303
304static 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(lock: &kbd_dev->lock, flags);
312}
313
314static 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(size: sizeof(struct hv_kbd_dev), GFP_KERNEL);
322 hv_serio = kzalloc(size: 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(x: &kbd_dev->wait_event);
332 hv_set_drvdata(dev: hv_dev, data: 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(p: hv_serio->name, q: dev_name(dev: &hv_dev->device),
338 size: sizeof(hv_serio->name));
339 strscpy(p: hv_serio->phys, q: dev_name(dev: &hv_dev->device),
340 size: sizeof(hv_serio->phys));
341
342 hv_serio->start = hv_kbd_start;
343 hv_serio->stop = hv_kbd_stop;
344
345 error = vmbus_open(channel: hv_dev->channel,
346 KBD_VSC_SEND_RING_BUFFER_SIZE,
347 KBD_VSC_RECV_RING_BUFFER_SIZE,
348 NULL, userdatalen: 0,
349 onchannel_callback: hv_kbd_on_channel_callback,
350 context: 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(dev: &hv_dev->device, enable: true);
361
362 return 0;
363
364err_close_vmbus:
365 vmbus_close(channel: hv_dev->channel);
366err_free_mem:
367 kfree(objp: hv_serio);
368 kfree(objp: kbd_dev);
369 return error;
370}
371
372static void hv_kbd_remove(struct hv_device *hv_dev)
373{
374 struct hv_kbd_dev *kbd_dev = hv_get_drvdata(dev: hv_dev);
375
376 serio_unregister_port(serio: kbd_dev->hv_serio);
377 vmbus_close(channel: hv_dev->channel);
378 kfree(objp: kbd_dev);
379
380 hv_set_drvdata(dev: hv_dev, NULL);
381}
382
383static int hv_kbd_suspend(struct hv_device *hv_dev)
384{
385 vmbus_close(channel: hv_dev->channel);
386
387 return 0;
388}
389
390static int hv_kbd_resume(struct hv_device *hv_dev)
391{
392 int ret;
393
394 ret = vmbus_open(channel: hv_dev->channel,
395 KBD_VSC_SEND_RING_BUFFER_SIZE,
396 KBD_VSC_RECV_RING_BUFFER_SIZE,
397 NULL, userdatalen: 0,
398 onchannel_callback: hv_kbd_on_channel_callback,
399 context: hv_dev);
400 if (ret == 0)
401 ret = hv_kbd_connect_to_vsp(hv_dev);
402
403 return ret;
404}
405
406static const struct hv_vmbus_device_id id_table[] = {
407 /* Keyboard guid */
408 { HV_KBD_GUID, },
409 { },
410};
411
412MODULE_DEVICE_TABLE(vmbus, id_table);
413
414static struct hv_driver hv_kbd_drv = {
415 .name = KBUILD_MODNAME,
416 .id_table = id_table,
417 .probe = hv_kbd_probe,
418 .remove = hv_kbd_remove,
419 .suspend = hv_kbd_suspend,
420 .resume = hv_kbd_resume,
421 .driver = {
422 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
423 },
424};
425
426static int __init hv_kbd_init(void)
427{
428 return vmbus_driver_register(&hv_kbd_drv);
429}
430
431static void __exit hv_kbd_exit(void)
432{
433 vmbus_driver_unregister(hv_driver: &hv_kbd_drv);
434}
435
436MODULE_LICENSE("GPL");
437MODULE_DESCRIPTION("Microsoft Hyper-V Synthetic Keyboard Driver");
438
439module_init(hv_kbd_init);
440module_exit(hv_kbd_exit);
441

source code of linux/drivers/input/serio/hyperv-keyboard.c