xref: /freebsd/sys/amd64/vmm/io/vhpet.c (revision e796cc77c586c2955b2f3940dbf4991b31e8d289)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2013 Tycho Nightingale <tycho.nightingale@pluribusnetworks.com>
5  * Copyright (c) 2013 Neel Natu <neel@freebsd.org>
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * $FreeBSD$
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include <sys/param.h>
36 #include <sys/lock.h>
37 #include <sys/mutex.h>
38 #include <sys/kernel.h>
39 #include <sys/malloc.h>
40 #include <sys/systm.h>
41 
42 #include <dev/acpica/acpi_hpet.h>
43 
44 #include <machine/vmm.h>
45 #include <machine/vmm_dev.h>
46 
47 #include "vmm_lapic.h"
48 #include "vatpic.h"
49 #include "vioapic.h"
50 #include "vhpet.h"
51 
52 #include "vmm_ktr.h"
53 
54 static MALLOC_DEFINE(M_VHPET, "vhpet", "bhyve virtual hpet");
55 
56 #define	HPET_FREQ	16777216		/* 16.7 (2^24) Mhz */
57 #define	FS_PER_S	1000000000000000ul
58 
59 /* Timer N Configuration and Capabilities Register */
60 #define	HPET_TCAP_RO_MASK	(HPET_TCAP_INT_ROUTE 	|		\
61 				 HPET_TCAP_FSB_INT_DEL	|		\
62 				 HPET_TCAP_SIZE		|		\
63 				 HPET_TCAP_PER_INT)
64 /*
65  * HPET requires at least 3 timers and up to 32 timers per block.
66  */
67 #define	VHPET_NUM_TIMERS	8
68 CTASSERT(VHPET_NUM_TIMERS >= 3 && VHPET_NUM_TIMERS <= 32);
69 
70 struct vhpet_callout_arg {
71 	struct vhpet *vhpet;
72 	int timer_num;
73 };
74 
75 struct vhpet {
76 	struct vm	*vm;
77 	struct mtx	mtx;
78 	sbintime_t	freq_sbt;
79 
80 	uint64_t	config;		/* Configuration */
81 	uint64_t	isr;		/* Interrupt Status */
82 	uint32_t	countbase;	/* HPET counter base value */
83 	sbintime_t	countbase_sbt;	/* uptime corresponding to base value */
84 
85 	struct {
86 		uint64_t	cap_config;	/* Configuration */
87 		uint64_t	msireg;		/* FSB interrupt routing */
88 		uint32_t	compval;	/* Comparator */
89 		uint32_t	comprate;
90 		struct callout	callout;
91 		sbintime_t	callout_sbt;	/* time when counter==compval */
92 		struct vhpet_callout_arg arg;
93 	} timer[VHPET_NUM_TIMERS];
94 };
95 
96 #define	VHPET_LOCK(vhp)		mtx_lock(&((vhp)->mtx))
97 #define	VHPET_UNLOCK(vhp)	mtx_unlock(&((vhp)->mtx))
98 
99 static void vhpet_start_timer(struct vhpet *vhpet, int n, uint32_t counter,
100     sbintime_t now);
101 
102 static uint64_t
103 vhpet_capabilities(void)
104 {
105 	uint64_t cap = 0;
106 
107 	cap |= 0x8086 << 16;			/* vendor id */
108 	cap |= (VHPET_NUM_TIMERS - 1) << 8;	/* number of timers */
109 	cap |= 1;				/* revision */
110 	cap &= ~HPET_CAP_COUNT_SIZE;		/* 32-bit timer */
111 
112 	cap &= 0xffffffff;
113 	cap |= (FS_PER_S / HPET_FREQ) << 32;	/* tick period in fs */
114 
115 	return (cap);
116 }
117 
118 static __inline bool
119 vhpet_counter_enabled(struct vhpet *vhpet)
120 {
121 
122 	return ((vhpet->config & HPET_CNF_ENABLE) ? true : false);
123 }
124 
125 static __inline bool
126 vhpet_timer_msi_enabled(struct vhpet *vhpet, int n)
127 {
128 	const uint64_t msi_enable = HPET_TCAP_FSB_INT_DEL | HPET_TCNF_FSB_EN;
129 
130 	if ((vhpet->timer[n].cap_config & msi_enable) == msi_enable)
131 		return (true);
132 	else
133 		return (false);
134 }
135 
136 static __inline int
137 vhpet_timer_ioapic_pin(struct vhpet *vhpet, int n)
138 {
139 	/*
140 	 * If the timer is configured to use MSI then treat it as if the
141 	 * timer is not connected to the ioapic.
142 	 */
143 	if (vhpet_timer_msi_enabled(vhpet, n))
144 		return (0);
145 
146 	return ((vhpet->timer[n].cap_config & HPET_TCNF_INT_ROUTE) >> 9);
147 }
148 
149 static uint32_t
150 vhpet_counter(struct vhpet *vhpet, sbintime_t *nowptr)
151 {
152 	uint32_t val;
153 	sbintime_t now, delta;
154 
155 	val = vhpet->countbase;
156 	if (vhpet_counter_enabled(vhpet)) {
157 		now = sbinuptime();
158 		delta = now - vhpet->countbase_sbt;
159 		KASSERT(delta >= 0, ("vhpet_counter: uptime went backwards: "
160 		    "%#lx to %#lx", vhpet->countbase_sbt, now));
161 		val += delta / vhpet->freq_sbt;
162 		if (nowptr != NULL)
163 			*nowptr = now;
164 	} else {
165 		/*
166 		 * The sbinuptime corresponding to the 'countbase' is
167 		 * meaningless when the counter is disabled. Make sure
168 		 * that the caller doesn't want to use it.
169 		 */
170 		KASSERT(nowptr == NULL, ("vhpet_counter: nowptr must be NULL"));
171 	}
172 	return (val);
173 }
174 
175 static void
176 vhpet_timer_clear_isr(struct vhpet *vhpet, int n)
177 {
178 	int pin;
179 
180 	if (vhpet->isr & (1 << n)) {
181 		pin = vhpet_timer_ioapic_pin(vhpet, n);
182 		KASSERT(pin != 0, ("vhpet timer %d irq incorrectly routed", n));
183 		vioapic_deassert_irq(vhpet->vm, pin);
184 		vhpet->isr &= ~(1 << n);
185 	}
186 }
187 
188 static __inline bool
189 vhpet_periodic_timer(struct vhpet *vhpet, int n)
190 {
191 
192 	return ((vhpet->timer[n].cap_config & HPET_TCNF_TYPE) != 0);
193 }
194 
195 static __inline bool
196 vhpet_timer_interrupt_enabled(struct vhpet *vhpet, int n)
197 {
198 
199 	return ((vhpet->timer[n].cap_config & HPET_TCNF_INT_ENB) != 0);
200 }
201 
202 static __inline bool
203 vhpet_timer_edge_trig(struct vhpet *vhpet, int n)
204 {
205 
206 	KASSERT(!vhpet_timer_msi_enabled(vhpet, n), ("vhpet_timer_edge_trig: "
207 	    "timer %d is using MSI", n));
208 
209 	if ((vhpet->timer[n].cap_config & HPET_TCNF_INT_TYPE) == 0)
210 		return (true);
211 	else
212 		return (false);
213 }
214 
215 static void
216 vhpet_timer_interrupt(struct vhpet *vhpet, int n)
217 {
218 	int pin;
219 
220 	/* If interrupts are not enabled for this timer then just return. */
221 	if (!vhpet_timer_interrupt_enabled(vhpet, n))
222 		return;
223 
224 	/*
225 	 * If a level triggered interrupt is already asserted then just return.
226 	 */
227 	if ((vhpet->isr & (1 << n)) != 0) {
228 		VM_CTR1(vhpet->vm, "hpet t%d intr is already asserted", n);
229 		return;
230 	}
231 
232 	if (vhpet_timer_msi_enabled(vhpet, n)) {
233 		lapic_intr_msi(vhpet->vm, vhpet->timer[n].msireg >> 32,
234 		    vhpet->timer[n].msireg & 0xffffffff);
235 		return;
236 	}
237 
238 	pin = vhpet_timer_ioapic_pin(vhpet, n);
239 	if (pin == 0) {
240 		VM_CTR1(vhpet->vm, "hpet t%d intr is not routed to ioapic", n);
241 		return;
242 	}
243 
244 	if (vhpet_timer_edge_trig(vhpet, n)) {
245 		vioapic_pulse_irq(vhpet->vm, pin);
246 	} else {
247 		vhpet->isr |= 1 << n;
248 		vioapic_assert_irq(vhpet->vm, pin);
249 	}
250 }
251 
252 static void
253 vhpet_adjust_compval(struct vhpet *vhpet, int n, uint32_t counter)
254 {
255 	uint32_t compval, comprate, compnext;
256 
257 	KASSERT(vhpet->timer[n].comprate != 0, ("hpet t%d is not periodic", n));
258 
259 	compval = vhpet->timer[n].compval;
260 	comprate = vhpet->timer[n].comprate;
261 
262 	/*
263 	 * Calculate the comparator value to be used for the next periodic
264 	 * interrupt.
265 	 *
266 	 * This function is commonly called from the callout handler.
267 	 * In this scenario the 'counter' is ahead of 'compval'. To find
268 	 * the next value to program into the accumulator we divide the
269 	 * number space between 'compval' and 'counter' into 'comprate'
270 	 * sized units. The 'compval' is rounded up such that is "ahead"
271 	 * of 'counter'.
272 	 */
273 	compnext = compval + ((counter - compval) / comprate + 1) * comprate;
274 
275 	vhpet->timer[n].compval = compnext;
276 }
277 
278 static void
279 vhpet_handler(void *a)
280 {
281 	int n;
282 	uint32_t counter;
283 	sbintime_t now;
284 	struct vhpet *vhpet;
285 	struct callout *callout;
286 	struct vhpet_callout_arg *arg;
287 
288 	arg = a;
289 	vhpet = arg->vhpet;
290 	n = arg->timer_num;
291 	callout = &vhpet->timer[n].callout;
292 
293 	VM_CTR1(vhpet->vm, "hpet t%d fired", n);
294 
295 	VHPET_LOCK(vhpet);
296 
297 	if (callout_pending(callout))		/* callout was reset */
298 		goto done;
299 
300 	if (!callout_active(callout))		/* callout was stopped */
301 		goto done;
302 
303 	callout_deactivate(callout);
304 
305 	if (!vhpet_counter_enabled(vhpet))
306 		panic("vhpet(%p) callout with counter disabled", vhpet);
307 
308 	counter = vhpet_counter(vhpet, &now);
309 	vhpet_start_timer(vhpet, n, counter, now);
310 	vhpet_timer_interrupt(vhpet, n);
311 done:
312 	VHPET_UNLOCK(vhpet);
313 	return;
314 }
315 
316 static void
317 vhpet_stop_timer(struct vhpet *vhpet, int n, sbintime_t now)
318 {
319 
320 	VM_CTR1(vhpet->vm, "hpet t%d stopped", n);
321 	callout_stop(&vhpet->timer[n].callout);
322 
323 	/*
324 	 * If the callout was scheduled to expire in the past but hasn't
325 	 * had a chance to execute yet then trigger the timer interrupt
326 	 * here. Failing to do so will result in a missed timer interrupt
327 	 * in the guest. This is especially bad in one-shot mode because
328 	 * the next interrupt has to wait for the counter to wrap around.
329 	 */
330 	if (vhpet->timer[n].callout_sbt < now) {
331 		VM_CTR1(vhpet->vm, "hpet t%d interrupt triggered after "
332 		    "stopping timer", n);
333 		vhpet_timer_interrupt(vhpet, n);
334 	}
335 }
336 
337 static void
338 vhpet_start_timer(struct vhpet *vhpet, int n, uint32_t counter, sbintime_t now)
339 {
340 	sbintime_t delta, precision;
341 
342 	if (vhpet->timer[n].comprate != 0)
343 		vhpet_adjust_compval(vhpet, n, counter);
344 	else {
345 		/*
346 		 * In one-shot mode it is the guest's responsibility to make
347 		 * sure that the comparator value is not in the "past". The
348 		 * hardware doesn't have any belt-and-suspenders to deal with
349 		 * this so we don't either.
350 		 */
351 	}
352 
353 	delta = (vhpet->timer[n].compval - counter) * vhpet->freq_sbt;
354 	precision = delta >> tc_precexp;
355 	vhpet->timer[n].callout_sbt = now + delta;
356 	callout_reset_sbt(&vhpet->timer[n].callout, vhpet->timer[n].callout_sbt,
357 	    precision, vhpet_handler, &vhpet->timer[n].arg, C_ABSOLUTE);
358 }
359 
360 static void
361 vhpet_start_counting(struct vhpet *vhpet)
362 {
363 	int i;
364 
365 	vhpet->countbase_sbt = sbinuptime();
366 	for (i = 0; i < VHPET_NUM_TIMERS; i++) {
367 		/*
368 		 * Restart the timers based on the value of the main counter
369 		 * when it stopped counting.
370 		 */
371 		vhpet_start_timer(vhpet, i, vhpet->countbase,
372 		    vhpet->countbase_sbt);
373 	}
374 }
375 
376 static void
377 vhpet_stop_counting(struct vhpet *vhpet, uint32_t counter, sbintime_t now)
378 {
379 	int i;
380 
381 	vhpet->countbase = counter;
382 	for (i = 0; i < VHPET_NUM_TIMERS; i++)
383 		vhpet_stop_timer(vhpet, i, now);
384 }
385 
386 static __inline void
387 update_register(uint64_t *regptr, uint64_t data, uint64_t mask)
388 {
389 
390 	*regptr &= ~mask;
391 	*regptr |= (data & mask);
392 }
393 
394 static void
395 vhpet_timer_update_config(struct vhpet *vhpet, int n, uint64_t data,
396     uint64_t mask)
397 {
398 	bool clear_isr;
399 	int old_pin, new_pin;
400 	uint32_t allowed_irqs;
401 	uint64_t oldval, newval;
402 
403 	if (vhpet_timer_msi_enabled(vhpet, n) ||
404 	    vhpet_timer_edge_trig(vhpet, n)) {
405 		if (vhpet->isr & (1 << n))
406 			panic("vhpet timer %d isr should not be asserted", n);
407 	}
408 	old_pin = vhpet_timer_ioapic_pin(vhpet, n);
409 	oldval = vhpet->timer[n].cap_config;
410 
411 	newval = oldval;
412 	update_register(&newval, data, mask);
413 	newval &= ~(HPET_TCAP_RO_MASK | HPET_TCNF_32MODE);
414 	newval |= oldval & HPET_TCAP_RO_MASK;
415 
416 	if (newval == oldval)
417 		return;
418 
419 	vhpet->timer[n].cap_config = newval;
420 	VM_CTR2(vhpet->vm, "hpet t%d cap_config set to 0x%016x", n, newval);
421 
422 	/*
423 	 * Validate the interrupt routing in the HPET_TCNF_INT_ROUTE field.
424 	 * If it does not match the bits set in HPET_TCAP_INT_ROUTE then set
425 	 * it to the default value of 0.
426 	 */
427 	allowed_irqs = vhpet->timer[n].cap_config >> 32;
428 	new_pin = vhpet_timer_ioapic_pin(vhpet, n);
429 	if (new_pin != 0 && (allowed_irqs & (1 << new_pin)) == 0) {
430 		VM_CTR3(vhpet->vm, "hpet t%d configured invalid irq %d, "
431 		    "allowed_irqs 0x%08x", n, new_pin, allowed_irqs);
432 		new_pin = 0;
433 		vhpet->timer[n].cap_config &= ~HPET_TCNF_INT_ROUTE;
434 	}
435 
436 	if (!vhpet_periodic_timer(vhpet, n))
437 		vhpet->timer[n].comprate = 0;
438 
439 	/*
440 	 * If the timer's ISR bit is set then clear it in the following cases:
441 	 * - interrupt is disabled
442 	 * - interrupt type is changed from level to edge or fsb.
443 	 * - interrupt routing is changed
444 	 *
445 	 * This is to ensure that this timer's level triggered interrupt does
446 	 * not remain asserted forever.
447 	 */
448 	if (vhpet->isr & (1 << n)) {
449 		KASSERT(old_pin != 0, ("timer %d isr asserted to ioapic pin %d",
450 		    n, old_pin));
451 		if (!vhpet_timer_interrupt_enabled(vhpet, n))
452 			clear_isr = true;
453 		else if (vhpet_timer_msi_enabled(vhpet, n))
454 			clear_isr = true;
455 		else if (vhpet_timer_edge_trig(vhpet, n))
456 			clear_isr = true;
457 		else if (vhpet_timer_ioapic_pin(vhpet, n) != old_pin)
458 			clear_isr = true;
459 		else
460 			clear_isr = false;
461 
462 		if (clear_isr) {
463 			VM_CTR1(vhpet->vm, "hpet t%d isr cleared due to "
464 			    "configuration change", n);
465 			vioapic_deassert_irq(vhpet->vm, old_pin);
466 			vhpet->isr &= ~(1 << n);
467 		}
468 	}
469 }
470 
471 int
472 vhpet_mmio_write(void *vm, int vcpuid, uint64_t gpa, uint64_t val, int size,
473     void *arg)
474 {
475 	struct vhpet *vhpet;
476 	uint64_t data, mask, oldval, val64;
477 	uint32_t isr_clear_mask, old_compval, old_comprate, counter;
478 	sbintime_t now, *nowptr;
479 	int i, offset;
480 
481 	vhpet = vm_hpet(vm);
482 	offset = gpa - VHPET_BASE;
483 
484 	VHPET_LOCK(vhpet);
485 
486 	/* Accesses to the HPET should be 4 or 8 bytes wide */
487 	switch (size) {
488 	case 8:
489 		mask = 0xffffffffffffffff;
490 		data = val;
491 		break;
492 	case 4:
493 		mask = 0xffffffff;
494 		data = val;
495 		if ((offset & 0x4) != 0) {
496 			mask <<= 32;
497 			data <<= 32;
498 		}
499 		break;
500 	default:
501 		VM_CTR2(vhpet->vm, "hpet invalid mmio write: "
502 		    "offset 0x%08x, size %d", offset, size);
503 		goto done;
504 	}
505 
506 	/* Access to the HPET should be naturally aligned to its width */
507 	if (offset & (size - 1)) {
508 		VM_CTR2(vhpet->vm, "hpet invalid mmio write: "
509 		    "offset 0x%08x, size %d", offset, size);
510 		goto done;
511 	}
512 
513 	if (offset == HPET_CONFIG || offset == HPET_CONFIG + 4) {
514 		/*
515 		 * Get the most recent value of the counter before updating
516 		 * the 'config' register. If the HPET is going to be disabled
517 		 * then we need to update 'countbase' with the value right
518 		 * before it is disabled.
519 		 */
520 		nowptr = vhpet_counter_enabled(vhpet) ? &now : NULL;
521 		counter = vhpet_counter(vhpet, nowptr);
522 		oldval = vhpet->config;
523 		update_register(&vhpet->config, data, mask);
524 
525 		/*
526 		 * LegacyReplacement Routing is not supported so clear the
527 		 * bit explicitly.
528 		 */
529 		vhpet->config &= ~HPET_CNF_LEG_RT;
530 
531 		if ((oldval ^ vhpet->config) & HPET_CNF_ENABLE) {
532 			if (vhpet_counter_enabled(vhpet)) {
533 				vhpet_start_counting(vhpet);
534 				VM_CTR0(vhpet->vm, "hpet enabled");
535 			} else {
536 				vhpet_stop_counting(vhpet, counter, now);
537 				VM_CTR0(vhpet->vm, "hpet disabled");
538 			}
539 		}
540 		goto done;
541 	}
542 
543 	if (offset == HPET_ISR || offset == HPET_ISR + 4) {
544 		isr_clear_mask = vhpet->isr & data;
545 		for (i = 0; i < VHPET_NUM_TIMERS; i++) {
546 			if ((isr_clear_mask & (1 << i)) != 0) {
547 				VM_CTR1(vhpet->vm, "hpet t%d isr cleared", i);
548 				vhpet_timer_clear_isr(vhpet, i);
549 			}
550 		}
551 		goto done;
552 	}
553 
554 	if (offset == HPET_MAIN_COUNTER || offset == HPET_MAIN_COUNTER + 4) {
555 		/* Zero-extend the counter to 64-bits before updating it */
556 		val64 = vhpet_counter(vhpet, NULL);
557 		update_register(&val64, data, mask);
558 		vhpet->countbase = val64;
559 		if (vhpet_counter_enabled(vhpet))
560 			vhpet_start_counting(vhpet);
561 		goto done;
562 	}
563 
564 	for (i = 0; i < VHPET_NUM_TIMERS; i++) {
565 		if (offset == HPET_TIMER_CAP_CNF(i) ||
566 		    offset == HPET_TIMER_CAP_CNF(i) + 4) {
567 			vhpet_timer_update_config(vhpet, i, data, mask);
568 			break;
569 		}
570 
571 		if (offset == HPET_TIMER_COMPARATOR(i) ||
572 		    offset == HPET_TIMER_COMPARATOR(i) + 4) {
573 			old_compval = vhpet->timer[i].compval;
574 			old_comprate = vhpet->timer[i].comprate;
575 			if (vhpet_periodic_timer(vhpet, i)) {
576 				/*
577 				 * In periodic mode writes to the comparator
578 				 * change the 'compval' register only if the
579 				 * HPET_TCNF_VAL_SET bit is set in the config
580 				 * register.
581 				 */
582 				val64 = vhpet->timer[i].comprate;
583 				update_register(&val64, data, mask);
584 				vhpet->timer[i].comprate = val64;
585 				if ((vhpet->timer[i].cap_config &
586 				    HPET_TCNF_VAL_SET) != 0) {
587 					vhpet->timer[i].compval = val64;
588 				}
589 			} else {
590 				KASSERT(vhpet->timer[i].comprate == 0,
591 				    ("vhpet one-shot timer %d has invalid "
592 				    "rate %u", i, vhpet->timer[i].comprate));
593 				val64 = vhpet->timer[i].compval;
594 				update_register(&val64, data, mask);
595 				vhpet->timer[i].compval = val64;
596 			}
597 			vhpet->timer[i].cap_config &= ~HPET_TCNF_VAL_SET;
598 
599 			if (vhpet->timer[i].compval != old_compval ||
600 			    vhpet->timer[i].comprate != old_comprate) {
601 				if (vhpet_counter_enabled(vhpet)) {
602 					counter = vhpet_counter(vhpet, &now);
603 					vhpet_start_timer(vhpet, i, counter,
604 					    now);
605 				}
606 			}
607 			break;
608 		}
609 
610 		if (offset == HPET_TIMER_FSB_VAL(i) ||
611 		    offset == HPET_TIMER_FSB_ADDR(i)) {
612 			update_register(&vhpet->timer[i].msireg, data, mask);
613 			break;
614 		}
615 	}
616 done:
617 	VHPET_UNLOCK(vhpet);
618 	return (0);
619 }
620 
621 int
622 vhpet_mmio_read(void *vm, int vcpuid, uint64_t gpa, uint64_t *rval, int size,
623     void *arg)
624 {
625 	int i, offset;
626 	struct vhpet *vhpet;
627 	uint64_t data;
628 
629 	vhpet = vm_hpet(vm);
630 	offset = gpa - VHPET_BASE;
631 
632 	VHPET_LOCK(vhpet);
633 
634 	/* Accesses to the HPET should be 4 or 8 bytes wide */
635 	if (size != 4 && size != 8) {
636 		VM_CTR2(vhpet->vm, "hpet invalid mmio read: "
637 		    "offset 0x%08x, size %d", offset, size);
638 		data = 0;
639 		goto done;
640 	}
641 
642 	/* Access to the HPET should be naturally aligned to its width */
643 	if (offset & (size - 1)) {
644 		VM_CTR2(vhpet->vm, "hpet invalid mmio read: "
645 		    "offset 0x%08x, size %d", offset, size);
646 		data = 0;
647 		goto done;
648 	}
649 
650 	if (offset == HPET_CAPABILITIES || offset == HPET_CAPABILITIES + 4) {
651 		data = vhpet_capabilities();
652 		goto done;
653 	}
654 
655 	if (offset == HPET_CONFIG || offset == HPET_CONFIG + 4) {
656 		data = vhpet->config;
657 		goto done;
658 	}
659 
660 	if (offset == HPET_ISR || offset == HPET_ISR + 4) {
661 		data = vhpet->isr;
662 		goto done;
663 	}
664 
665 	if (offset == HPET_MAIN_COUNTER || offset == HPET_MAIN_COUNTER + 4) {
666 		data = vhpet_counter(vhpet, NULL);
667 		goto done;
668 	}
669 
670 	for (i = 0; i < VHPET_NUM_TIMERS; i++) {
671 		if (offset == HPET_TIMER_CAP_CNF(i) ||
672 		    offset == HPET_TIMER_CAP_CNF(i) + 4) {
673 			data = vhpet->timer[i].cap_config;
674 			break;
675 		}
676 
677 		if (offset == HPET_TIMER_COMPARATOR(i) ||
678 		    offset == HPET_TIMER_COMPARATOR(i) + 4) {
679 			data = vhpet->timer[i].compval;
680 			break;
681 		}
682 
683 		if (offset == HPET_TIMER_FSB_VAL(i) ||
684 		    offset == HPET_TIMER_FSB_ADDR(i)) {
685 			data = vhpet->timer[i].msireg;
686 			break;
687 		}
688 	}
689 
690 	if (i >= VHPET_NUM_TIMERS)
691 		data = 0;
692 done:
693 	VHPET_UNLOCK(vhpet);
694 
695 	if (size == 4) {
696 		if (offset & 0x4)
697 			data >>= 32;
698 	}
699 	*rval = data;
700 	return (0);
701 }
702 
703 struct vhpet *
704 vhpet_init(struct vm *vm)
705 {
706 	int i, pincount;
707 	struct vhpet *vhpet;
708 	uint64_t allowed_irqs;
709 	struct vhpet_callout_arg *arg;
710 	struct bintime bt;
711 
712 	vhpet = malloc(sizeof(struct vhpet), M_VHPET, M_WAITOK | M_ZERO);
713         vhpet->vm = vm;
714 	mtx_init(&vhpet->mtx, "vhpet lock", NULL, MTX_DEF);
715 
716 	FREQ2BT(HPET_FREQ, &bt);
717 	vhpet->freq_sbt = bttosbt(bt);
718 
719 	pincount = vioapic_pincount(vm);
720 	if (pincount >= 32)
721 		allowed_irqs = 0xff000000;	/* irqs 24-31 */
722 	else if (pincount >= 20)
723 		allowed_irqs = 0xf << (pincount - 4);	/* 4 upper irqs */
724 	else
725 		allowed_irqs = 0;
726 
727 	/*
728 	 * Initialize HPET timer hardware state.
729 	 */
730 	for (i = 0; i < VHPET_NUM_TIMERS; i++) {
731 		vhpet->timer[i].cap_config = allowed_irqs << 32;
732 		vhpet->timer[i].cap_config |= HPET_TCAP_PER_INT;
733 		vhpet->timer[i].cap_config |= HPET_TCAP_FSB_INT_DEL;
734 
735 		vhpet->timer[i].compval = 0xffffffff;
736 		callout_init(&vhpet->timer[i].callout, 1);
737 
738 		arg = &vhpet->timer[i].arg;
739 		arg->vhpet = vhpet;
740 		arg->timer_num = i;
741 	}
742 
743 	return (vhpet);
744 }
745 
746 void
747 vhpet_cleanup(struct vhpet *vhpet)
748 {
749 	int i;
750 
751 	for (i = 0; i < VHPET_NUM_TIMERS; i++)
752 		callout_drain(&vhpet->timer[i].callout);
753 
754 	free(vhpet, M_VHPET);
755 }
756 
757 int
758 vhpet_getcap(struct vm_hpet_cap *cap)
759 {
760 
761 	cap->capabilities = vhpet_capabilities();
762 	return (0);
763 }
764