xref: /freebsd/sys/amd64/vmm/io/vatpit.c (revision 069ac184) 
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 #include "opt_bhyve_snapshot.h"
31 
32 #include <sys/param.h>
33 #include <sys/types.h>
34 #include <sys/queue.h>
35 #include <sys/kernel.h>
36 #include <sys/lock.h>
37 #include <sys/malloc.h>
38 #include <sys/mutex.h>
39 #include <sys/systm.h>
40 
41 #include <machine/vmm.h>
42 #include <machine/vmm_snapshot.h>
43 
44 #include "vmm_ktr.h"
45 #include "vatpic.h"
46 #include "vioapic.h"
47 #include "vatpit.h"
48 
49 static MALLOC_DEFINE(M_VATPIT, "atpit", "bhyve virtual atpit (8254)");
50 
51 #define	VATPIT_LOCK(vatpit)		mtx_lock_spin(&((vatpit)->mtx))
52 #define	VATPIT_UNLOCK(vatpit)		mtx_unlock_spin(&((vatpit)->mtx))
53 #define	VATPIT_LOCKED(vatpit)		mtx_owned(&((vatpit)->mtx))
54 
55 #define	TIMER_SEL_MASK		0xc0
56 #define	TIMER_RW_MASK		0x30
57 #define	TIMER_MODE_MASK		0x0f
58 #define	TIMER_SEL_READBACK	0xc0
59 
60 #define	TIMER_STS_OUT		0x80
61 #define	TIMER_STS_NULLCNT	0x40
62 
63 #define	TIMER_RB_LCTR		0x20
64 #define	TIMER_RB_LSTATUS	0x10
65 #define	TIMER_RB_CTR_2		0x08
66 #define	TIMER_RB_CTR_1		0x04
67 #define	TIMER_RB_CTR_0		0x02
68 
69 #define	TMR2_OUT_STS		0x20
70 
71 #define	PIT_8254_FREQ		1193182
72 #define	TIMER_DIV(freq, hz)	(((freq) + (hz) / 2) / (hz))
73 
74 struct vatpit_callout_arg {
75 	struct vatpit	*vatpit;
76 	int		channel_num;
77 };
78 
79 struct channel {
80 	int		mode;
81 	uint16_t	initial;	/* initial counter value */
82 	struct bintime	now_bt;		/* uptime when counter was loaded */
83 	uint8_t		cr[2];
84 	uint8_t		ol[2];
85 	bool		slatched;	/* status latched */
86 	uint8_t		status;
87 	int		crbyte;
88 	int		olbyte;
89 	int		frbyte;
90 	struct callout	callout;
91 	struct bintime	callout_bt;	/* target time */
92 	struct vatpit_callout_arg callout_arg;
93 };
94 
95 struct vatpit {
96 	struct vm	*vm;
97 	struct mtx	mtx;
98 
99 	struct bintime	freq_bt;
100 
101 	struct channel	channel[3];
102 };
103 
104 static void pit_timer_start_cntr0(struct vatpit *vatpit);
105 
106 static uint64_t
107 vatpit_delta_ticks(struct vatpit *vatpit, struct channel *c)
108 {
109 	struct bintime delta;
110 	uint64_t result;
111 
112 	binuptime(&delta);
113 	bintime_sub(&delta, &c->now_bt);
114 
115 	result = delta.sec * PIT_8254_FREQ;
116 	result += delta.frac / vatpit->freq_bt.frac;
117 
118 	return (result);
119 }
120 
121 static int
122 vatpit_get_out(struct vatpit *vatpit, int channel)
123 {
124 	struct channel *c;
125 	uint64_t delta_ticks;
126 	int out;
127 
128 	c = &vatpit->channel[channel];
129 
130 	switch (c->mode) {
131 	case TIMER_INTTC:
132 		delta_ticks = vatpit_delta_ticks(vatpit, c);
133 		out = (delta_ticks >= c->initial);
134 		break;
135 	default:
136 		out = 0;
137 		break;
138 	}
139 
140 	return (out);
141 }
142 
143 static void
144 vatpit_callout_handler(void *a)
145 {
146 	struct vatpit_callout_arg *arg = a;
147 	struct vatpit *vatpit;
148 	struct callout *callout;
149 	struct channel *c;
150 
151 	vatpit = arg->vatpit;
152 	c = &vatpit->channel[arg->channel_num];
153 	callout = &c->callout;
154 
155 	VM_CTR1(vatpit->vm, "atpit t%d fired", arg->channel_num);
156 
157 	VATPIT_LOCK(vatpit);
158 
159 	if (callout_pending(callout))		/* callout was reset */
160 		goto done;
161 
162 	if (!callout_active(callout))		/* callout was stopped */
163 		goto done;
164 
165 	callout_deactivate(callout);
166 
167 	if (c->mode == TIMER_RATEGEN) {
168 		pit_timer_start_cntr0(vatpit);
169 	}
170 
171 	vatpic_pulse_irq(vatpit->vm, 0);
172 	vioapic_pulse_irq(vatpit->vm, 2);
173 
174 done:
175 	VATPIT_UNLOCK(vatpit);
176 	return;
177 }
178 
179 static void
180 pit_timer_start_cntr0(struct vatpit *vatpit)
181 {
182 	struct channel *c;
183 	struct bintime now, delta;
184 	sbintime_t precision;
185 
186 	c = &vatpit->channel[0];
187 	if (c->initial != 0) {
188 		delta.sec = 0;
189 		delta.frac = vatpit->freq_bt.frac * c->initial;
190 		bintime_add(&c->callout_bt, &delta);
191 		precision = bttosbt(delta) >> tc_precexp;
192 
193 		/*
194 		 * Reset 'callout_bt' if the time that the callout
195 		 * was supposed to fire is more than 'c->initial'
196 		 * ticks in the past.
197 		 */
198 		binuptime(&now);
199 		if (bintime_cmp(&c->callout_bt, &now, <)) {
200 			c->callout_bt = now;
201 			bintime_add(&c->callout_bt, &delta);
202 		}
203 
204 		callout_reset_sbt(&c->callout, bttosbt(c->callout_bt),
205 		    precision, vatpit_callout_handler, &c->callout_arg,
206 		    C_ABSOLUTE);
207 	}
208 }
209 
210 static uint16_t
211 pit_update_counter(struct vatpit *vatpit, struct channel *c, bool latch)
212 {
213 	uint16_t lval;
214 	uint64_t delta_ticks;
215 
216 	/* cannot latch a new value until the old one has been consumed */
217 	if (latch && c->olbyte != 0)
218 		return (0);
219 
220 	if (c->initial == 0) {
221 		/*
222 		 * This is possibly an o/s bug - reading the value of
223 		 * the timer without having set up the initial value.
224 		 *
225 		 * The original user-space version of this code set
226 		 * the timer to 100hz in this condition; do the same
227 		 * here.
228 		 */
229 		c->initial = TIMER_DIV(PIT_8254_FREQ, 100);
230 		binuptime(&c->now_bt);
231 		c->status &= ~TIMER_STS_NULLCNT;
232 	}
233 
234 	delta_ticks = vatpit_delta_ticks(vatpit, c);
235 	lval = c->initial - delta_ticks % c->initial;
236 
237 	if (latch) {
238 		c->olbyte = 2;
239 		c->ol[1] = lval;		/* LSB */
240 		c->ol[0] = lval >> 8;		/* MSB */
241 	}
242 
243 	return (lval);
244 }
245 
246 static int
247 pit_readback1(struct vatpit *vatpit, int channel, uint8_t cmd)
248 {
249 	struct channel *c;
250 
251 	c = &vatpit->channel[channel];
252 
253 	/*
254 	 * Latch the count/status of the timer if not already latched.
255 	 * N.B. that the count/status latch-select bits are active-low.
256 	 */
257 	if (!(cmd & TIMER_RB_LCTR) && !c->olbyte) {
258 		(void) pit_update_counter(vatpit, c, true);
259 	}
260 
261 	if (!(cmd & TIMER_RB_LSTATUS) && !c->slatched) {
262 		c->slatched = true;
263 		/*
264 		 * For mode 0, see if the elapsed time is greater
265 		 * than the initial value - this results in the
266 		 * output pin being set to 1 in the status byte.
267 		 */
268 		if (c->mode == TIMER_INTTC && vatpit_get_out(vatpit, channel))
269 			c->status |= TIMER_STS_OUT;
270 		else
271 			c->status &= ~TIMER_STS_OUT;
272 	}
273 
274 	return (0);
275 }
276 
277 static int
278 pit_readback(struct vatpit *vatpit, uint8_t cmd)
279 {
280 	int error;
281 
282 	/*
283 	 * The readback command can apply to all timers.
284 	 */
285 	error = 0;
286 	if (cmd & TIMER_RB_CTR_0)
287 		error = pit_readback1(vatpit, 0, cmd);
288 	if (!error && cmd & TIMER_RB_CTR_1)
289 		error = pit_readback1(vatpit, 1, cmd);
290 	if (!error && cmd & TIMER_RB_CTR_2)
291 		error = pit_readback1(vatpit, 2, cmd);
292 
293 	return (error);
294 }
295 
296 static int
297 vatpit_update_mode(struct vatpit *vatpit, uint8_t val)
298 {
299 	struct channel *c;
300 	int sel, rw, mode;
301 
302 	sel = val & TIMER_SEL_MASK;
303 	rw = val & TIMER_RW_MASK;
304 	mode = val & TIMER_MODE_MASK;
305 
306 	if (sel == TIMER_SEL_READBACK)
307 		return (pit_readback(vatpit, val));
308 
309 	if (rw != TIMER_LATCH && rw != TIMER_16BIT)
310 		return (-1);
311 
312 	if (rw != TIMER_LATCH) {
313 		/*
314 		 * Counter mode is not affected when issuing a
315 		 * latch command.
316 		 */
317 		if (mode != TIMER_INTTC &&
318 		    mode != TIMER_RATEGEN &&
319 		    mode != TIMER_SQWAVE &&
320 		    mode != TIMER_SWSTROBE)
321 			return (-1);
322 	}
323 
324 	c = &vatpit->channel[sel >> 6];
325 	if (rw == TIMER_LATCH)
326 		pit_update_counter(vatpit, c, true);
327 	else {
328 		c->mode = mode;
329 		c->olbyte = 0;	/* reset latch after reprogramming */
330 		c->status |= TIMER_STS_NULLCNT;
331 	}
332 
333 	return (0);
334 }
335 
336 int
337 vatpit_handler(struct vm *vm, bool in, int port, int bytes, uint32_t *eax)
338 {
339 	struct vatpit *vatpit;
340 	struct channel *c;
341 	uint8_t val;
342 	int error;
343 
344 	vatpit = vm_atpit(vm);
345 
346 	if (bytes != 1)
347 		return (-1);
348 
349 	val = *eax;
350 
351 	if (port == TIMER_MODE) {
352 		if (in) {
353 			VM_CTR0(vatpit->vm, "vatpit attempt to read mode");
354 			return (-1);
355 		}
356 
357 		VATPIT_LOCK(vatpit);
358 		error = vatpit_update_mode(vatpit, val);
359 		VATPIT_UNLOCK(vatpit);
360 
361 		return (error);
362 	}
363 
364 	/* counter ports */
365 	KASSERT(port >= TIMER_CNTR0 && port <= TIMER_CNTR2,
366 	    ("invalid port 0x%x", port));
367 	c = &vatpit->channel[port - TIMER_CNTR0];
368 
369 	VATPIT_LOCK(vatpit);
370 	if (in && c->slatched) {
371 		/*
372 		 * Return the status byte if latched
373 		 */
374 		*eax = c->status;
375 		c->slatched = false;
376 		c->status = 0;
377 	} else if (in) {
378 		/*
379 		 * The spec says that once the output latch is completely
380 		 * read it should revert to "following" the counter. Use
381 		 * the free running counter for this case (i.e. Linux
382 		 * TSC calibration). Assuming the access mode is 16-bit,
383 		 * toggle the MSB/LSB bit on each read.
384 		 */
385 		if (c->olbyte == 0) {
386 			uint16_t tmp;
387 
388 			tmp = pit_update_counter(vatpit, c, false);
389 			if (c->frbyte)
390 				tmp >>= 8;
391 			tmp &= 0xff;
392 			*eax = tmp;
393 			c->frbyte ^= 1;
394 		}  else
395 			*eax = c->ol[--c->olbyte];
396 	} else {
397 		c->cr[c->crbyte++] = *eax;
398 		if (c->crbyte == 2) {
399 			c->status &= ~TIMER_STS_NULLCNT;
400 			c->frbyte = 0;
401 			c->crbyte = 0;
402 			c->initial = c->cr[0] | (uint16_t)c->cr[1] << 8;
403 			binuptime(&c->now_bt);
404 			/* Start an interval timer for channel 0 */
405 			if (port == TIMER_CNTR0) {
406 				c->callout_bt = c->now_bt;
407 				pit_timer_start_cntr0(vatpit);
408 			}
409 			if (c->initial == 0)
410 				c->initial = 0xffff;
411 		}
412 	}
413 	VATPIT_UNLOCK(vatpit);
414 
415 	return (0);
416 }
417 
418 int
419 vatpit_nmisc_handler(struct vm *vm, bool in, int port, int bytes,
420     uint32_t *eax)
421 {
422 	struct vatpit *vatpit;
423 
424 	vatpit = vm_atpit(vm);
425 
426 	if (in) {
427 			VATPIT_LOCK(vatpit);
428 			if (vatpit_get_out(vatpit, 2))
429 				*eax = TMR2_OUT_STS;
430 			else
431 				*eax = 0;
432 
433 			VATPIT_UNLOCK(vatpit);
434 	}
435 
436 	return (0);
437 }
438 
439 struct vatpit *
440 vatpit_init(struct vm *vm)
441 {
442 	struct vatpit *vatpit;
443 	struct vatpit_callout_arg *arg;
444 	int i;
445 
446 	vatpit = malloc(sizeof(struct vatpit), M_VATPIT, M_WAITOK | M_ZERO);
447 	vatpit->vm = vm;
448 
449 	mtx_init(&vatpit->mtx, "vatpit lock", NULL, MTX_SPIN);
450 
451 	FREQ2BT(PIT_8254_FREQ, &vatpit->freq_bt);
452 
453 	for (i = 0; i < 3; i++) {
454 		callout_init(&vatpit->channel[i].callout, 1);
455 		arg = &vatpit->channel[i].callout_arg;
456 		arg->vatpit = vatpit;
457 		arg->channel_num = i;
458 	}
459 
460 	return (vatpit);
461 }
462 
463 void
464 vatpit_cleanup(struct vatpit *vatpit)
465 {
466 	int i;
467 
468 	for (i = 0; i < 3; i++)
469 		callout_drain(&vatpit->channel[i].callout);
470 
471 	mtx_destroy(&vatpit->mtx);
472 	free(vatpit, M_VATPIT);
473 }
474 
475 #ifdef BHYVE_SNAPSHOT
476 int
477 vatpit_snapshot(struct vatpit *vatpit, struct vm_snapshot_meta *meta)
478 {
479 	int ret;
480 	int i;
481 	struct channel *channel;
482 
483 	SNAPSHOT_VAR_OR_LEAVE(vatpit->freq_bt.sec, meta, ret, done);
484 	SNAPSHOT_VAR_OR_LEAVE(vatpit->freq_bt.frac, meta, ret, done);
485 
486 	/* properly restore timers; they will NOT work currently */
487 	printf("%s: snapshot restore does not reset timers!\r\n", __func__);
488 
489 	for (i = 0; i < nitems(vatpit->channel); i++) {
490 		channel = &vatpit->channel[i];
491 
492 		SNAPSHOT_VAR_OR_LEAVE(channel->mode, meta, ret, done);
493 		SNAPSHOT_VAR_OR_LEAVE(channel->initial, meta, ret, done);
494 		SNAPSHOT_VAR_OR_LEAVE(channel->now_bt.sec, meta, ret, done);
495 		SNAPSHOT_VAR_OR_LEAVE(channel->now_bt.frac, meta, ret, done);
496 		SNAPSHOT_BUF_OR_LEAVE(channel->cr, sizeof(channel->cr),
497 			meta, ret, done);
498 		SNAPSHOT_BUF_OR_LEAVE(channel->ol, sizeof(channel->ol),
499 			meta, ret, done);
500 		SNAPSHOT_VAR_OR_LEAVE(channel->slatched, meta, ret, done);
501 		SNAPSHOT_VAR_OR_LEAVE(channel->status, meta, ret, done);
502 		SNAPSHOT_VAR_OR_LEAVE(channel->crbyte, meta, ret, done);
503 		SNAPSHOT_VAR_OR_LEAVE(channel->frbyte, meta, ret, done);
504 		SNAPSHOT_VAR_OR_LEAVE(channel->callout_bt.sec, meta, ret, done);
505 		SNAPSHOT_VAR_OR_LEAVE(channel->callout_bt.frac, meta, ret,
506 			done);
507 	}
508 
509 done:
510 	return (ret);
511 }
512 #endif
513