xref: /freebsd/sys/amd64/vmm/io/vatpit.c (revision af23369a6deaaeb612ab266eb88b8bb8d560c322) 
1 /*-
2  * Copyright (c) 2014 Tycho Nightingale <tycho.nightingale@pluribusnetworks.com>
3  * Copyright (c) 2011 NetApp, Inc.
4  * All rights reserved.
5  * Copyright (c) 2018 Joyent, Inc.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include "opt_bhyve_snapshot.h"
33 
34 #include <sys/param.h>
35 #include <sys/types.h>
36 #include <sys/queue.h>
37 #include <sys/kernel.h>
38 #include <sys/lock.h>
39 #include <sys/malloc.h>
40 #include <sys/mutex.h>
41 #include <sys/systm.h>
42 
43 #include <machine/vmm.h>
44 #include <machine/vmm_snapshot.h>
45 
46 #include "vmm_ktr.h"
47 #include "vatpic.h"
48 #include "vioapic.h"
49 #include "vatpit.h"
50 
51 static MALLOC_DEFINE(M_VATPIT, "atpit", "bhyve virtual atpit (8254)");
52 
53 #define	VATPIT_LOCK(vatpit)		mtx_lock_spin(&((vatpit)->mtx))
54 #define	VATPIT_UNLOCK(vatpit)		mtx_unlock_spin(&((vatpit)->mtx))
55 #define	VATPIT_LOCKED(vatpit)		mtx_owned(&((vatpit)->mtx))
56 
57 #define	TIMER_SEL_MASK		0xc0
58 #define	TIMER_RW_MASK		0x30
59 #define	TIMER_MODE_MASK		0x0f
60 #define	TIMER_SEL_READBACK	0xc0
61 
62 #define	TIMER_STS_OUT		0x80
63 #define	TIMER_STS_NULLCNT	0x40
64 
65 #define	TIMER_RB_LCTR		0x20
66 #define	TIMER_RB_LSTATUS	0x10
67 #define	TIMER_RB_CTR_2		0x08
68 #define	TIMER_RB_CTR_1		0x04
69 #define	TIMER_RB_CTR_0		0x02
70 
71 #define	TMR2_OUT_STS		0x20
72 
73 #define	PIT_8254_FREQ		1193182
74 #define	TIMER_DIV(freq, hz)	(((freq) + (hz) / 2) / (hz))
75 
76 struct vatpit_callout_arg {
77 	struct vatpit	*vatpit;
78 	int		channel_num;
79 };
80 
81 struct channel {
82 	int		mode;
83 	uint16_t	initial;	/* initial counter value */
84 	struct bintime	now_bt;		/* uptime when counter was loaded */
85 	uint8_t		cr[2];
86 	uint8_t		ol[2];
87 	bool		slatched;	/* status latched */
88 	uint8_t		status;
89 	int		crbyte;
90 	int		olbyte;
91 	int		frbyte;
92 	struct callout	callout;
93 	struct bintime	callout_bt;	/* target time */
94 	struct vatpit_callout_arg callout_arg;
95 };
96 
97 struct vatpit {
98 	struct vm	*vm;
99 	struct mtx	mtx;
100 
101 	struct bintime	freq_bt;
102 
103 	struct channel	channel[3];
104 };
105 
106 static void pit_timer_start_cntr0(struct vatpit *vatpit);
107 
108 static uint64_t
109 vatpit_delta_ticks(struct vatpit *vatpit, struct channel *c)
110 {
111 	struct bintime delta;
112 	uint64_t result;
113 
114 	binuptime(&delta);
115 	bintime_sub(&delta, &c->now_bt);
116 
117 	result = delta.sec * PIT_8254_FREQ;
118 	result += delta.frac / vatpit->freq_bt.frac;
119 
120 	return (result);
121 }
122 
123 static int
124 vatpit_get_out(struct vatpit *vatpit, int channel)
125 {
126 	struct channel *c;
127 	uint64_t delta_ticks;
128 	int out;
129 
130 	c = &vatpit->channel[channel];
131 
132 	switch (c->mode) {
133 	case TIMER_INTTC:
134 		delta_ticks = vatpit_delta_ticks(vatpit, c);
135 		out = (delta_ticks >= c->initial);
136 		break;
137 	default:
138 		out = 0;
139 		break;
140 	}
141 
142 	return (out);
143 }
144 
145 static void
146 vatpit_callout_handler(void *a)
147 {
148 	struct vatpit_callout_arg *arg = a;
149 	struct vatpit *vatpit;
150 	struct callout *callout;
151 	struct channel *c;
152 
153 	vatpit = arg->vatpit;
154 	c = &vatpit->channel[arg->channel_num];
155 	callout = &c->callout;
156 
157 	VM_CTR1(vatpit->vm, "atpit t%d fired", arg->channel_num);
158 
159 	VATPIT_LOCK(vatpit);
160 
161 	if (callout_pending(callout))		/* callout was reset */
162 		goto done;
163 
164 	if (!callout_active(callout))		/* callout was stopped */
165 		goto done;
166 
167 	callout_deactivate(callout);
168 
169 	if (c->mode == TIMER_RATEGEN) {
170 		pit_timer_start_cntr0(vatpit);
171 	}
172 
173 	vatpic_pulse_irq(vatpit->vm, 0);
174 	vioapic_pulse_irq(vatpit->vm, 2);
175 
176 done:
177 	VATPIT_UNLOCK(vatpit);
178 	return;
179 }
180 
181 static void
182 pit_timer_start_cntr0(struct vatpit *vatpit)
183 {
184 	struct channel *c;
185 	struct bintime now, delta;
186 	sbintime_t precision;
187 
188 	c = &vatpit->channel[0];
189 	if (c->initial != 0) {
190 		delta.sec = 0;
191 		delta.frac = vatpit->freq_bt.frac * c->initial;
192 		bintime_add(&c->callout_bt, &delta);
193 		precision = bttosbt(delta) >> tc_precexp;
194 
195 		/*
196 		 * Reset 'callout_bt' if the time that the callout
197 		 * was supposed to fire is more than 'c->initial'
198 		 * ticks in the past.
199 		 */
200 		binuptime(&now);
201 		if (bintime_cmp(&c->callout_bt, &now, <)) {
202 			c->callout_bt = now;
203 			bintime_add(&c->callout_bt, &delta);
204 		}
205 
206 		callout_reset_sbt(&c->callout, bttosbt(c->callout_bt),
207 		    precision, vatpit_callout_handler, &c->callout_arg,
208 		    C_ABSOLUTE);
209 	}
210 }
211 
212 static uint16_t
213 pit_update_counter(struct vatpit *vatpit, struct channel *c, bool latch)
214 {
215 	uint16_t lval;
216 	uint64_t delta_ticks;
217 
218 	/* cannot latch a new value until the old one has been consumed */
219 	if (latch && c->olbyte != 0)
220 		return (0);
221 
222 	if (c->initial == 0) {
223 		/*
224 		 * This is possibly an o/s bug - reading the value of
225 		 * the timer without having set up the initial value.
226 		 *
227 		 * The original user-space version of this code set
228 		 * the timer to 100hz in this condition; do the same
229 		 * here.
230 		 */
231 		c->initial = TIMER_DIV(PIT_8254_FREQ, 100);
232 		binuptime(&c->now_bt);
233 		c->status &= ~TIMER_STS_NULLCNT;
234 	}
235 
236 	delta_ticks = vatpit_delta_ticks(vatpit, c);
237 	lval = c->initial - delta_ticks % c->initial;
238 
239 	if (latch) {
240 		c->olbyte = 2;
241 		c->ol[1] = lval;		/* LSB */
242 		c->ol[0] = lval >> 8;		/* MSB */
243 	}
244 
245 	return (lval);
246 }
247 
248 static int
249 pit_readback1(struct vatpit *vatpit, int channel, uint8_t cmd)
250 {
251 	struct channel *c;
252 
253 	c = &vatpit->channel[channel];
254 
255 	/*
256 	 * Latch the count/status of the timer if not already latched.
257 	 * N.B. that the count/status latch-select bits are active-low.
258 	 */
259 	if (!(cmd & TIMER_RB_LCTR) && !c->olbyte) {
260 		(void) pit_update_counter(vatpit, c, true);
261 	}
262 
263 	if (!(cmd & TIMER_RB_LSTATUS) && !c->slatched) {
264 		c->slatched = true;
265 		/*
266 		 * For mode 0, see if the elapsed time is greater
267 		 * than the initial value - this results in the
268 		 * output pin being set to 1 in the status byte.
269 		 */
270 		if (c->mode == TIMER_INTTC && vatpit_get_out(vatpit, channel))
271 			c->status |= TIMER_STS_OUT;
272 		else
273 			c->status &= ~TIMER_STS_OUT;
274 	}
275 
276 	return (0);
277 }
278 
279 static int
280 pit_readback(struct vatpit *vatpit, uint8_t cmd)
281 {
282 	int error;
283 
284 	/*
285 	 * The readback command can apply to all timers.
286 	 */
287 	error = 0;
288 	if (cmd & TIMER_RB_CTR_0)
289 		error = pit_readback1(vatpit, 0, cmd);
290 	if (!error && cmd & TIMER_RB_CTR_1)
291 		error = pit_readback1(vatpit, 1, cmd);
292 	if (!error && cmd & TIMER_RB_CTR_2)
293 		error = pit_readback1(vatpit, 2, cmd);
294 
295 	return (error);
296 }
297 
298 static int
299 vatpit_update_mode(struct vatpit *vatpit, uint8_t val)
300 {
301 	struct channel *c;
302 	int sel, rw, mode;
303 
304 	sel = val & TIMER_SEL_MASK;
305 	rw = val & TIMER_RW_MASK;
306 	mode = val & TIMER_MODE_MASK;
307 
308 	if (sel == TIMER_SEL_READBACK)
309 		return (pit_readback(vatpit, val));
310 
311 	if (rw != TIMER_LATCH && rw != TIMER_16BIT)
312 		return (-1);
313 
314 	if (rw != TIMER_LATCH) {
315 		/*
316 		 * Counter mode is not affected when issuing a
317 		 * latch command.
318 		 */
319 		if (mode != TIMER_INTTC &&
320 		    mode != TIMER_RATEGEN &&
321 		    mode != TIMER_SQWAVE &&
322 		    mode != TIMER_SWSTROBE)
323 			return (-1);
324 	}
325 
326 	c = &vatpit->channel[sel >> 6];
327 	if (rw == TIMER_LATCH)
328 		pit_update_counter(vatpit, c, true);
329 	else {
330 		c->mode = mode;
331 		c->olbyte = 0;	/* reset latch after reprogramming */
332 		c->status |= TIMER_STS_NULLCNT;
333 	}
334 
335 	return (0);
336 }
337 
338 int
339 vatpit_handler(struct vm *vm, bool in, int port, int bytes, uint32_t *eax)
340 {
341 	struct vatpit *vatpit;
342 	struct channel *c;
343 	uint8_t val;
344 	int error;
345 
346 	vatpit = vm_atpit(vm);
347 
348 	if (bytes != 1)
349 		return (-1);
350 
351 	val = *eax;
352 
353 	if (port == TIMER_MODE) {
354 		if (in) {
355 			VM_CTR0(vatpit->vm, "vatpit attempt to read mode");
356 			return (-1);
357 		}
358 
359 		VATPIT_LOCK(vatpit);
360 		error = vatpit_update_mode(vatpit, val);
361 		VATPIT_UNLOCK(vatpit);
362 
363 		return (error);
364 	}
365 
366 	/* counter ports */
367 	KASSERT(port >= TIMER_CNTR0 && port <= TIMER_CNTR2,
368 	    ("invalid port 0x%x", port));
369 	c = &vatpit->channel[port - TIMER_CNTR0];
370 
371 	VATPIT_LOCK(vatpit);
372 	if (in && c->slatched) {
373 		/*
374 		 * Return the status byte if latched
375 		 */
376 		*eax = c->status;
377 		c->slatched = false;
378 		c->status = 0;
379 	} else if (in) {
380 		/*
381 		 * The spec says that once the output latch is completely
382 		 * read it should revert to "following" the counter. Use
383 		 * the free running counter for this case (i.e. Linux
384 		 * TSC calibration). Assuming the access mode is 16-bit,
385 		 * toggle the MSB/LSB bit on each read.
386 		 */
387 		if (c->olbyte == 0) {
388 			uint16_t tmp;
389 
390 			tmp = pit_update_counter(vatpit, c, false);
391 			if (c->frbyte)
392 				tmp >>= 8;
393 			tmp &= 0xff;
394 			*eax = tmp;
395 			c->frbyte ^= 1;
396 		}  else
397 			*eax = c->ol[--c->olbyte];
398 	} else {
399 		c->cr[c->crbyte++] = *eax;
400 		if (c->crbyte == 2) {
401 			c->status &= ~TIMER_STS_NULLCNT;
402 			c->frbyte = 0;
403 			c->crbyte = 0;
404 			c->initial = c->cr[0] | (uint16_t)c->cr[1] << 8;
405 			binuptime(&c->now_bt);
406 			/* Start an interval timer for channel 0 */
407 			if (port == TIMER_CNTR0) {
408 				c->callout_bt = c->now_bt;
409 				pit_timer_start_cntr0(vatpit);
410 			}
411 			if (c->initial == 0)
412 				c->initial = 0xffff;
413 		}
414 	}
415 	VATPIT_UNLOCK(vatpit);
416 
417 	return (0);
418 }
419 
420 int
421 vatpit_nmisc_handler(struct vm *vm, bool in, int port, int bytes,
422     uint32_t *eax)
423 {
424 	struct vatpit *vatpit;
425 
426 	vatpit = vm_atpit(vm);
427 
428 	if (in) {
429 			VATPIT_LOCK(vatpit);
430 			if (vatpit_get_out(vatpit, 2))
431 				*eax = TMR2_OUT_STS;
432 			else
433 				*eax = 0;
434 
435 			VATPIT_UNLOCK(vatpit);
436 	}
437 
438 	return (0);
439 }
440 
441 struct vatpit *
442 vatpit_init(struct vm *vm)
443 {
444 	struct vatpit *vatpit;
445 	struct vatpit_callout_arg *arg;
446 	int i;
447 
448 	vatpit = malloc(sizeof(struct vatpit), M_VATPIT, M_WAITOK | M_ZERO);
449 	vatpit->vm = vm;
450 
451 	mtx_init(&vatpit->mtx, "vatpit lock", NULL, MTX_SPIN);
452 
453 	FREQ2BT(PIT_8254_FREQ, &vatpit->freq_bt);
454 
455 	for (i = 0; i < 3; i++) {
456 		callout_init(&vatpit->channel[i].callout, 1);
457 		arg = &vatpit->channel[i].callout_arg;
458 		arg->vatpit = vatpit;
459 		arg->channel_num = i;
460 	}
461 
462 	return (vatpit);
463 }
464 
465 void
466 vatpit_cleanup(struct vatpit *vatpit)
467 {
468 	int i;
469 
470 	for (i = 0; i < 3; i++)
471 		callout_drain(&vatpit->channel[i].callout);
472 
473 	mtx_destroy(&vatpit->mtx);
474 	free(vatpit, M_VATPIT);
475 }
476 
477 #ifdef BHYVE_SNAPSHOT
478 int
479 vatpit_snapshot(struct vatpit *vatpit, struct vm_snapshot_meta *meta)
480 {
481 	int ret;
482 	int i;
483 	struct channel *channel;
484 
485 	SNAPSHOT_VAR_OR_LEAVE(vatpit->freq_bt.sec, meta, ret, done);
486 	SNAPSHOT_VAR_OR_LEAVE(vatpit->freq_bt.frac, meta, ret, done);
487 
488 	/* properly restore timers; they will NOT work currently */
489 	printf("%s: snapshot restore does not reset timers!\r\n", __func__);
490 
491 	for (i = 0; i < nitems(vatpit->channel); i++) {
492 		channel = &vatpit->channel[i];
493 
494 		SNAPSHOT_VAR_OR_LEAVE(channel->mode, meta, ret, done);
495 		SNAPSHOT_VAR_OR_LEAVE(channel->initial, meta, ret, done);
496 		SNAPSHOT_VAR_OR_LEAVE(channel->now_bt.sec, meta, ret, done);
497 		SNAPSHOT_VAR_OR_LEAVE(channel->now_bt.frac, meta, ret, done);
498 		SNAPSHOT_BUF_OR_LEAVE(channel->cr, sizeof(channel->cr),
499 			meta, ret, done);
500 		SNAPSHOT_BUF_OR_LEAVE(channel->ol, sizeof(channel->ol),
501 			meta, ret, done);
502 		SNAPSHOT_VAR_OR_LEAVE(channel->slatched, meta, ret, done);
503 		SNAPSHOT_VAR_OR_LEAVE(channel->status, meta, ret, done);
504 		SNAPSHOT_VAR_OR_LEAVE(channel->crbyte, meta, ret, done);
505 		SNAPSHOT_VAR_OR_LEAVE(channel->frbyte, meta, ret, done);
506 		SNAPSHOT_VAR_OR_LEAVE(channel->callout_bt.sec, meta, ret, done);
507 		SNAPSHOT_VAR_OR_LEAVE(channel->callout_bt.frac, meta, ret,
508 			done);
509 	}
510 
511 done:
512 	return (ret);
513 }
514 #endif
515