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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(hv_dev);
104 struct synth_kbd_keystroke *ks_msg;
105 u32 msg_type = __le32_to_cpu(msg->header.type);
106 u32 info;
107 u16 scan_code;
108
109 switch (msg_type) {
110 case SYNTH_KBD_PROTOCOL_RESPONSE:
111 /*
112 * Validate the information provided by the host.
113 * If the host is giving us a bogus packet,
114 * drop the packet (hoping the problem
115 * goes away).
116 */
117 if (msg_length < sizeof(struct synth_kbd_protocol_response)) {
118 dev_err(&hv_dev->device,
119 "Illegal protocol response packet (len: %d)\n",
120 msg_length);
121 break;
122 }
123
124 memcpy(&kbd_dev->protocol_resp, msg,
125 sizeof(struct synth_kbd_protocol_response));
126 complete(&kbd_dev->wait_event);
127 break;
128
129 case SYNTH_KBD_EVENT:
130 /*
131 * Validate the information provided by the host.
132 * If the host is giving us a bogus packet,
133 * drop the packet (hoping the problem
134 * goes away).
135 */
136 if (msg_length < sizeof(struct synth_kbd_keystroke)) {
137 dev_err(&hv_dev->device,
138 "Illegal keyboard event packet (len: %d)\n",
139 msg_length);
140 break;
141 }
142
143 ks_msg = (struct synth_kbd_keystroke *)msg;
144 info = __le32_to_cpu(ks_msg->info);
145
146 /*
147 * Inject the information through the serio interrupt.
148 */
149 scoped_guard(spinlock_irqsave, &kbd_dev->lock) {
150 if (kbd_dev->started) {
151 if (info & IS_E0)
152 serio_interrupt(kbd_dev->hv_serio,
153 XTKBD_EMUL0, 0);
154 if (info & IS_E1)
155 serio_interrupt(kbd_dev->hv_serio,
156 XTKBD_EMUL1, 0);
157 scan_code = __le16_to_cpu(ks_msg->make_code);
158 if (info & IS_BREAK)
159 scan_code |= XTKBD_RELEASE;
160
161 serio_interrupt(kbd_dev->hv_serio,
162 scan_code, 0);
163 }
164 }
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
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_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(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
292static int hv_kbd_start(struct serio *serio)
293{
294 struct hv_kbd_dev *kbd_dev = serio->port_data;
295
296 guard(spinlock_irqsave)(&kbd_dev->lock);
297
298 kbd_dev->started = true;
299
300 return 0;
301}
302
303static void hv_kbd_stop(struct serio *serio)
304{
305 struct hv_kbd_dev *kbd_dev = serio->port_data;
306
307 guard(spinlock_irqsave)(&kbd_dev->lock);
308
309 kbd_dev->started = false;
310}
311
312static int hv_kbd_probe(struct hv_device *hv_dev,
313 const struct hv_vmbus_device_id *dev_id)
314{
315 struct hv_kbd_dev *kbd_dev;
316 struct serio *hv_serio;
317 int error;
318
319 kbd_dev = kzalloc_obj(*kbd_dev);
320 hv_serio = kzalloc_obj(*hv_serio);
321 if (!kbd_dev || !hv_serio) {
322 error = -ENOMEM;
323 goto err_free_mem;
324 }
325
326 kbd_dev->hv_dev = hv_dev;
327 kbd_dev->hv_serio = hv_serio;
328 spin_lock_init(&kbd_dev->lock);
329 init_completion(&kbd_dev->wait_event);
330 hv_set_drvdata(hv_dev, kbd_dev);
331
332 hv_serio->dev.parent = &hv_dev->device;
333 hv_serio->id.type = SERIO_8042_XL;
334 hv_serio->port_data = kbd_dev;
335 strscpy(hv_serio->name, dev_name(&hv_dev->device),
336 sizeof(hv_serio->name));
337 strscpy(hv_serio->phys, dev_name(&hv_dev->device),
338 sizeof(hv_serio->phys));
339
340 hv_serio->start = hv_kbd_start;
341 hv_serio->stop = hv_kbd_stop;
342
343 error = vmbus_open(hv_dev->channel,
344 KBD_VSC_SEND_RING_BUFFER_SIZE,
345 KBD_VSC_RECV_RING_BUFFER_SIZE,
346 NULL, 0,
347 hv_kbd_on_channel_callback,
348 hv_dev);
349 if (error)
350 goto err_free_mem;
351
352 error = hv_kbd_connect_to_vsp(hv_dev);
353 if (error)
354 goto err_close_vmbus;
355
356 serio_register_port(kbd_dev->hv_serio);
357
358 device_init_wakeup(&hv_dev->device, true);
359
360 return 0;
361
362err_close_vmbus:
363 vmbus_close(hv_dev->channel);
364err_free_mem:
365 kfree(hv_serio);
366 kfree(kbd_dev);
367 return error;
368}
369
370static void hv_kbd_remove(struct hv_device *hv_dev)
371{
372 struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev);
373
374 serio_unregister_port(kbd_dev->hv_serio);
375 vmbus_close(hv_dev->channel);
376 kfree(kbd_dev);
377
378 hv_set_drvdata(hv_dev, NULL);
379}
380
381static int hv_kbd_suspend(struct hv_device *hv_dev)
382{
383 vmbus_close(hv_dev->channel);
384
385 return 0;
386}
387
388static int hv_kbd_resume(struct hv_device *hv_dev)
389{
390 int ret;
391
392 ret = vmbus_open(hv_dev->channel,
393 KBD_VSC_SEND_RING_BUFFER_SIZE,
394 KBD_VSC_RECV_RING_BUFFER_SIZE,
395 NULL, 0,
396 hv_kbd_on_channel_callback,
397 hv_dev);
398 if (ret == 0)
399 ret = hv_kbd_connect_to_vsp(hv_dev);
400
401 return ret;
402}
403
404static const struct hv_vmbus_device_id id_table[] = {
405 /* Keyboard guid */
406 { HV_KBD_GUID, },
407 { },
408};
409
410MODULE_DEVICE_TABLE(vmbus, id_table);
411
412static struct hv_driver hv_kbd_drv = {
413 .name = KBUILD_MODNAME,
414 .id_table = id_table,
415 .probe = hv_kbd_probe,
416 .remove = hv_kbd_remove,
417 .suspend = hv_kbd_suspend,
418 .resume = hv_kbd_resume,
419 .driver = {
420 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
421 },
422};
423
424static int __init hv_kbd_init(void)
425{
426 return vmbus_driver_register(&hv_kbd_drv);
427}
428
429static void __exit hv_kbd_exit(void)
430{
431 vmbus_driver_unregister(&hv_kbd_drv);
432}
433
434MODULE_LICENSE("GPL");
435MODULE_DESCRIPTION("Microsoft Hyper-V Synthetic Keyboard Driver");
436
437module_init(hv_kbd_init);
438module_exit(hv_kbd_exit);