1 /*
2 * 8253/8254 interval timer emulation
3 *
4 * Copyright (c) 2003-2004 Fabrice Bellard
5 * Copyright (c) 2006 Intel Corporation
6 * Copyright (c) 2007 Keir Fraser, XenSource Inc
7 * Copyright (c) 2008 Intel Corporation
8 * Copyright 2009 Red Hat, Inc. and/or its affiliates.
9 *
10 * Permission is hereby granted, free of charge, to any person obtaining a copy
11 * of this software and associated documentation files (the "Software"), to deal
12 * in the Software without restriction, including without limitation the rights
13 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
14 * copies of the Software, and to permit persons to whom the Software is
15 * furnished to do so, subject to the following conditions:
16 *
17 * The above copyright notice and this permission notice shall be included in
18 * all copies or substantial portions of the Software.
19 *
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
23 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
24 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
25 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
26 * THE SOFTWARE.
27 *
28 * Authors:
29 * Sheng Yang <sheng.yang@intel.com>
30 * Based on QEMU and Xen.
31 */
32
33 #define pr_fmt(fmt) "pit: " fmt
34
35 #include <linux/kvm_host.h>
36 #include <linux/slab.h>
37
38 #include "irq.h"
39 #include "i8254.h"
40 #include "x86.h"
41
42 #ifndef CONFIG_X86_64
43 #define mod_64(x, y) ((x) - (y) * div64_u64(x, y))
44 #else
45 #define mod_64(x, y) ((x) % (y))
46 #endif
47
48 #define RW_STATE_LSB 1
49 #define RW_STATE_MSB 2
50 #define RW_STATE_WORD0 3
51 #define RW_STATE_WORD1 4
52
53 /* Compute with 96 bit intermediate result: (a*b)/c */
muldiv64(u64 a,u32 b,u32 c)54 static u64 muldiv64(u64 a, u32 b, u32 c)
55 {
56 union {
57 u64 ll;
58 struct {
59 u32 low, high;
60 } l;
61 } u, res;
62 u64 rl, rh;
63
64 u.ll = a;
65 rl = (u64)u.l.low * (u64)b;
66 rh = (u64)u.l.high * (u64)b;
67 rh += (rl >> 32);
68 res.l.high = div64_u64(rh, c);
69 res.l.low = div64_u64(((mod_64(rh, c) << 32) + (rl & 0xffffffff)), c);
70 return res.ll;
71 }
72
pit_set_gate(struct kvm * kvm,int channel,u32 val)73 static void pit_set_gate(struct kvm *kvm, int channel, u32 val)
74 {
75 struct kvm_kpit_channel_state *c =
76 &kvm->arch.vpit->pit_state.channels[channel];
77
78 WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
79
80 switch (c->mode) {
81 default:
82 case 0:
83 case 4:
84 /* XXX: just disable/enable counting */
85 break;
86 case 1:
87 case 2:
88 case 3:
89 case 5:
90 /* Restart counting on rising edge. */
91 if (c->gate < val)
92 c->count_load_time = ktime_get();
93 break;
94 }
95
96 c->gate = val;
97 }
98
pit_get_gate(struct kvm * kvm,int channel)99 static int pit_get_gate(struct kvm *kvm, int channel)
100 {
101 WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
102
103 return kvm->arch.vpit->pit_state.channels[channel].gate;
104 }
105
__kpit_elapsed(struct kvm * kvm)106 static s64 __kpit_elapsed(struct kvm *kvm)
107 {
108 s64 elapsed;
109 ktime_t remaining;
110 struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
111
112 if (!ps->period)
113 return 0;
114
115 /*
116 * The Counter does not stop when it reaches zero. In
117 * Modes 0, 1, 4, and 5 the Counter ``wraps around'' to
118 * the highest count, either FFFF hex for binary counting
119 * or 9999 for BCD counting, and continues counting.
120 * Modes 2 and 3 are periodic; the Counter reloads
121 * itself with the initial count and continues counting
122 * from there.
123 */
124 remaining = hrtimer_get_remaining(&ps->timer);
125 elapsed = ps->period - ktime_to_ns(remaining);
126
127 return elapsed;
128 }
129
kpit_elapsed(struct kvm * kvm,struct kvm_kpit_channel_state * c,int channel)130 static s64 kpit_elapsed(struct kvm *kvm, struct kvm_kpit_channel_state *c,
131 int channel)
132 {
133 if (channel == 0)
134 return __kpit_elapsed(kvm);
135
136 return ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));
137 }
138
pit_get_count(struct kvm * kvm,int channel)139 static int pit_get_count(struct kvm *kvm, int channel)
140 {
141 struct kvm_kpit_channel_state *c =
142 &kvm->arch.vpit->pit_state.channels[channel];
143 s64 d, t;
144 int counter;
145
146 WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
147
148 t = kpit_elapsed(kvm, c, channel);
149 d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
150
151 switch (c->mode) {
152 case 0:
153 case 1:
154 case 4:
155 case 5:
156 counter = (c->count - d) & 0xffff;
157 break;
158 case 3:
159 /* XXX: may be incorrect for odd counts */
160 counter = c->count - (mod_64((2 * d), c->count));
161 break;
162 default:
163 counter = c->count - mod_64(d, c->count);
164 break;
165 }
166 return counter;
167 }
168
pit_get_out(struct kvm * kvm,int channel)169 static int pit_get_out(struct kvm *kvm, int channel)
170 {
171 struct kvm_kpit_channel_state *c =
172 &kvm->arch.vpit->pit_state.channels[channel];
173 s64 d, t;
174 int out;
175
176 WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
177
178 t = kpit_elapsed(kvm, c, channel);
179 d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
180
181 switch (c->mode) {
182 default:
183 case 0:
184 out = (d >= c->count);
185 break;
186 case 1:
187 out = (d < c->count);
188 break;
189 case 2:
190 out = ((mod_64(d, c->count) == 0) && (d != 0));
191 break;
192 case 3:
193 out = (mod_64(d, c->count) < ((c->count + 1) >> 1));
194 break;
195 case 4:
196 case 5:
197 out = (d == c->count);
198 break;
199 }
200
201 return out;
202 }
203
pit_latch_count(struct kvm * kvm,int channel)204 static void pit_latch_count(struct kvm *kvm, int channel)
205 {
206 struct kvm_kpit_channel_state *c =
207 &kvm->arch.vpit->pit_state.channels[channel];
208
209 WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
210
211 if (!c->count_latched) {
212 c->latched_count = pit_get_count(kvm, channel);
213 c->count_latched = c->rw_mode;
214 }
215 }
216
pit_latch_status(struct kvm * kvm,int channel)217 static void pit_latch_status(struct kvm *kvm, int channel)
218 {
219 struct kvm_kpit_channel_state *c =
220 &kvm->arch.vpit->pit_state.channels[channel];
221
222 WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
223
224 if (!c->status_latched) {
225 /* TODO: Return NULL COUNT (bit 6). */
226 c->status = ((pit_get_out(kvm, channel) << 7) |
227 (c->rw_mode << 4) |
228 (c->mode << 1) |
229 c->bcd);
230 c->status_latched = 1;
231 }
232 }
233
kvm_pit_ack_irq(struct kvm_irq_ack_notifier * kian)234 static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
235 {
236 struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
237 irq_ack_notifier);
238 int value;
239
240 spin_lock(&ps->inject_lock);
241 value = atomic_dec_return(&ps->pending);
242 if (value < 0)
243 /* spurious acks can be generated if, for example, the
244 * PIC is being reset. Handle it gracefully here
245 */
246 atomic_inc(&ps->pending);
247 else if (value > 0 && ps->reinject)
248 /* in this case, we had multiple outstanding pit interrupts
249 * that we needed to inject. Reinject
250 */
251 queue_kthread_work(&ps->pit->worker, &ps->pit->expired);
252 ps->irq_ack = 1;
253 spin_unlock(&ps->inject_lock);
254 }
255
__kvm_migrate_pit_timer(struct kvm_vcpu * vcpu)256 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
257 {
258 struct kvm_pit *pit = vcpu->kvm->arch.vpit;
259 struct hrtimer *timer;
260
261 if (!kvm_vcpu_is_bsp(vcpu) || !pit)
262 return;
263
264 timer = &pit->pit_state.timer;
265 mutex_lock(&pit->pit_state.lock);
266 if (hrtimer_cancel(timer))
267 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
268 mutex_unlock(&pit->pit_state.lock);
269 }
270
destroy_pit_timer(struct kvm_pit * pit)271 static void destroy_pit_timer(struct kvm_pit *pit)
272 {
273 hrtimer_cancel(&pit->pit_state.timer);
274 flush_kthread_work(&pit->expired);
275 }
276
pit_do_work(struct kthread_work * work)277 static void pit_do_work(struct kthread_work *work)
278 {
279 struct kvm_pit *pit = container_of(work, struct kvm_pit, expired);
280 struct kvm *kvm = pit->kvm;
281 struct kvm_vcpu *vcpu;
282 int i;
283 struct kvm_kpit_state *ps = &pit->pit_state;
284 int inject = 0;
285
286 /* Try to inject pending interrupts when
287 * last one has been acked.
288 */
289 spin_lock(&ps->inject_lock);
290 if (!ps->reinject)
291 inject = 1;
292 else if (ps->irq_ack) {
293 ps->irq_ack = 0;
294 inject = 1;
295 }
296 spin_unlock(&ps->inject_lock);
297 if (inject) {
298 kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1, false);
299 kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0, false);
300
301 /*
302 * Provides NMI watchdog support via Virtual Wire mode.
303 * The route is: PIT -> PIC -> LVT0 in NMI mode.
304 *
305 * Note: Our Virtual Wire implementation is simplified, only
306 * propagating PIT interrupts to all VCPUs when they have set
307 * LVT0 to NMI delivery. Other PIC interrupts are just sent to
308 * VCPU0, and only if its LVT0 is in EXTINT mode.
309 */
310 if (atomic_read(&kvm->arch.vapics_in_nmi_mode) > 0)
311 kvm_for_each_vcpu(i, vcpu, kvm)
312 kvm_apic_nmi_wd_deliver(vcpu);
313 }
314 }
315
pit_timer_fn(struct hrtimer * data)316 static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
317 {
318 struct kvm_kpit_state *ps = container_of(data, struct kvm_kpit_state, timer);
319 struct kvm_pit *pt = ps->kvm->arch.vpit;
320
321 if (ps->reinject)
322 atomic_inc(&ps->pending);
323
324 queue_kthread_work(&pt->worker, &pt->expired);
325
326 if (ps->is_periodic) {
327 hrtimer_add_expires_ns(&ps->timer, ps->period);
328 return HRTIMER_RESTART;
329 } else
330 return HRTIMER_NORESTART;
331 }
332
create_pit_timer(struct kvm * kvm,u32 val,int is_period)333 static void create_pit_timer(struct kvm *kvm, u32 val, int is_period)
334 {
335 struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
336 s64 interval;
337
338 if (!irqchip_in_kernel(kvm) || ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)
339 return;
340
341 interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
342
343 pr_debug("create pit timer, interval is %llu nsec\n", interval);
344
345 /* TODO The new value only affected after the retriggered */
346 hrtimer_cancel(&ps->timer);
347 flush_kthread_work(&ps->pit->expired);
348 ps->period = interval;
349 ps->is_periodic = is_period;
350
351 ps->timer.function = pit_timer_fn;
352 ps->kvm = ps->pit->kvm;
353
354 atomic_set(&ps->pending, 0);
355 ps->irq_ack = 1;
356
357 /*
358 * Do not allow the guest to program periodic timers with small
359 * interval, since the hrtimers are not throttled by the host
360 * scheduler.
361 */
362 if (ps->is_periodic) {
363 s64 min_period = min_timer_period_us * 1000LL;
364
365 if (ps->period < min_period) {
366 pr_info_ratelimited(
367 "kvm: requested %lld ns "
368 "i8254 timer period limited to %lld ns\n",
369 ps->period, min_period);
370 ps->period = min_period;
371 }
372 }
373
374 hrtimer_start(&ps->timer, ktime_add_ns(ktime_get(), interval),
375 HRTIMER_MODE_ABS);
376 }
377
pit_load_count(struct kvm * kvm,int channel,u32 val)378 static void pit_load_count(struct kvm *kvm, int channel, u32 val)
379 {
380 struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
381
382 WARN_ON(!mutex_is_locked(&ps->lock));
383
384 pr_debug("load_count val is %d, channel is %d\n", val, channel);
385
386 /*
387 * The largest possible initial count is 0; this is equivalent
388 * to 216 for binary counting and 104 for BCD counting.
389 */
390 if (val == 0)
391 val = 0x10000;
392
393 ps->channels[channel].count = val;
394
395 if (channel != 0) {
396 ps->channels[channel].count_load_time = ktime_get();
397 return;
398 }
399
400 /* Two types of timer
401 * mode 1 is one shot, mode 2 is period, otherwise del timer */
402 switch (ps->channels[0].mode) {
403 case 0:
404 case 1:
405 /* FIXME: enhance mode 4 precision */
406 case 4:
407 create_pit_timer(kvm, val, 0);
408 break;
409 case 2:
410 case 3:
411 create_pit_timer(kvm, val, 1);
412 break;
413 default:
414 destroy_pit_timer(kvm->arch.vpit);
415 }
416 }
417
kvm_pit_load_count(struct kvm * kvm,int channel,u32 val,int hpet_legacy_start)418 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start)
419 {
420 u8 saved_mode;
421 if (hpet_legacy_start) {
422 /* save existing mode for later reenablement */
423 saved_mode = kvm->arch.vpit->pit_state.channels[0].mode;
424 kvm->arch.vpit->pit_state.channels[0].mode = 0xff; /* disable timer */
425 pit_load_count(kvm, channel, val);
426 kvm->arch.vpit->pit_state.channels[0].mode = saved_mode;
427 } else {
428 pit_load_count(kvm, channel, val);
429 }
430 }
431
dev_to_pit(struct kvm_io_device * dev)432 static inline struct kvm_pit *dev_to_pit(struct kvm_io_device *dev)
433 {
434 return container_of(dev, struct kvm_pit, dev);
435 }
436
speaker_to_pit(struct kvm_io_device * dev)437 static inline struct kvm_pit *speaker_to_pit(struct kvm_io_device *dev)
438 {
439 return container_of(dev, struct kvm_pit, speaker_dev);
440 }
441
pit_in_range(gpa_t addr)442 static inline int pit_in_range(gpa_t addr)
443 {
444 return ((addr >= KVM_PIT_BASE_ADDRESS) &&
445 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
446 }
447
pit_ioport_write(struct kvm_io_device * this,gpa_t addr,int len,const void * data)448 static int pit_ioport_write(struct kvm_io_device *this,
449 gpa_t addr, int len, const void *data)
450 {
451 struct kvm_pit *pit = dev_to_pit(this);
452 struct kvm_kpit_state *pit_state = &pit->pit_state;
453 struct kvm *kvm = pit->kvm;
454 int channel, access;
455 struct kvm_kpit_channel_state *s;
456 u32 val = *(u32 *) data;
457 if (!pit_in_range(addr))
458 return -EOPNOTSUPP;
459
460 val &= 0xff;
461 addr &= KVM_PIT_CHANNEL_MASK;
462
463 mutex_lock(&pit_state->lock);
464
465 if (val != 0)
466 pr_debug("write addr is 0x%x, len is %d, val is 0x%x\n",
467 (unsigned int)addr, len, val);
468
469 if (addr == 3) {
470 channel = val >> 6;
471 if (channel == 3) {
472 /* Read-Back Command. */
473 for (channel = 0; channel < 3; channel++) {
474 s = &pit_state->channels[channel];
475 if (val & (2 << channel)) {
476 if (!(val & 0x20))
477 pit_latch_count(kvm, channel);
478 if (!(val & 0x10))
479 pit_latch_status(kvm, channel);
480 }
481 }
482 } else {
483 /* Select Counter <channel>. */
484 s = &pit_state->channels[channel];
485 access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
486 if (access == 0) {
487 pit_latch_count(kvm, channel);
488 } else {
489 s->rw_mode = access;
490 s->read_state = access;
491 s->write_state = access;
492 s->mode = (val >> 1) & 7;
493 if (s->mode > 5)
494 s->mode -= 4;
495 s->bcd = val & 1;
496 }
497 }
498 } else {
499 /* Write Count. */
500 s = &pit_state->channels[addr];
501 switch (s->write_state) {
502 default:
503 case RW_STATE_LSB:
504 pit_load_count(kvm, addr, val);
505 break;
506 case RW_STATE_MSB:
507 pit_load_count(kvm, addr, val << 8);
508 break;
509 case RW_STATE_WORD0:
510 s->write_latch = val;
511 s->write_state = RW_STATE_WORD1;
512 break;
513 case RW_STATE_WORD1:
514 pit_load_count(kvm, addr, s->write_latch | (val << 8));
515 s->write_state = RW_STATE_WORD0;
516 break;
517 }
518 }
519
520 mutex_unlock(&pit_state->lock);
521 return 0;
522 }
523
pit_ioport_read(struct kvm_io_device * this,gpa_t addr,int len,void * data)524 static int pit_ioport_read(struct kvm_io_device *this,
525 gpa_t addr, int len, void *data)
526 {
527 struct kvm_pit *pit = dev_to_pit(this);
528 struct kvm_kpit_state *pit_state = &pit->pit_state;
529 struct kvm *kvm = pit->kvm;
530 int ret, count;
531 struct kvm_kpit_channel_state *s;
532 if (!pit_in_range(addr))
533 return -EOPNOTSUPP;
534
535 addr &= KVM_PIT_CHANNEL_MASK;
536 if (addr == 3)
537 return 0;
538
539 s = &pit_state->channels[addr];
540
541 mutex_lock(&pit_state->lock);
542
543 if (s->status_latched) {
544 s->status_latched = 0;
545 ret = s->status;
546 } else if (s->count_latched) {
547 switch (s->count_latched) {
548 default:
549 case RW_STATE_LSB:
550 ret = s->latched_count & 0xff;
551 s->count_latched = 0;
552 break;
553 case RW_STATE_MSB:
554 ret = s->latched_count >> 8;
555 s->count_latched = 0;
556 break;
557 case RW_STATE_WORD0:
558 ret = s->latched_count & 0xff;
559 s->count_latched = RW_STATE_MSB;
560 break;
561 }
562 } else {
563 switch (s->read_state) {
564 default:
565 case RW_STATE_LSB:
566 count = pit_get_count(kvm, addr);
567 ret = count & 0xff;
568 break;
569 case RW_STATE_MSB:
570 count = pit_get_count(kvm, addr);
571 ret = (count >> 8) & 0xff;
572 break;
573 case RW_STATE_WORD0:
574 count = pit_get_count(kvm, addr);
575 ret = count & 0xff;
576 s->read_state = RW_STATE_WORD1;
577 break;
578 case RW_STATE_WORD1:
579 count = pit_get_count(kvm, addr);
580 ret = (count >> 8) & 0xff;
581 s->read_state = RW_STATE_WORD0;
582 break;
583 }
584 }
585
586 if (len > sizeof(ret))
587 len = sizeof(ret);
588 memcpy(data, (char *)&ret, len);
589
590 mutex_unlock(&pit_state->lock);
591 return 0;
592 }
593
speaker_ioport_write(struct kvm_io_device * this,gpa_t addr,int len,const void * data)594 static int speaker_ioport_write(struct kvm_io_device *this,
595 gpa_t addr, int len, const void *data)
596 {
597 struct kvm_pit *pit = speaker_to_pit(this);
598 struct kvm_kpit_state *pit_state = &pit->pit_state;
599 struct kvm *kvm = pit->kvm;
600 u32 val = *(u32 *) data;
601 if (addr != KVM_SPEAKER_BASE_ADDRESS)
602 return -EOPNOTSUPP;
603
604 mutex_lock(&pit_state->lock);
605 pit_state->speaker_data_on = (val >> 1) & 1;
606 pit_set_gate(kvm, 2, val & 1);
607 mutex_unlock(&pit_state->lock);
608 return 0;
609 }
610
speaker_ioport_read(struct kvm_io_device * this,gpa_t addr,int len,void * data)611 static int speaker_ioport_read(struct kvm_io_device *this,
612 gpa_t addr, int len, void *data)
613 {
614 struct kvm_pit *pit = speaker_to_pit(this);
615 struct kvm_kpit_state *pit_state = &pit->pit_state;
616 struct kvm *kvm = pit->kvm;
617 unsigned int refresh_clock;
618 int ret;
619 if (addr != KVM_SPEAKER_BASE_ADDRESS)
620 return -EOPNOTSUPP;
621
622 /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
623 refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
624
625 mutex_lock(&pit_state->lock);
626 ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
627 (pit_get_out(kvm, 2) << 5) | (refresh_clock << 4));
628 if (len > sizeof(ret))
629 len = sizeof(ret);
630 memcpy(data, (char *)&ret, len);
631 mutex_unlock(&pit_state->lock);
632 return 0;
633 }
634
kvm_pit_reset(struct kvm_pit * pit)635 void kvm_pit_reset(struct kvm_pit *pit)
636 {
637 int i;
638 struct kvm_kpit_channel_state *c;
639
640 mutex_lock(&pit->pit_state.lock);
641 pit->pit_state.flags = 0;
642 for (i = 0; i < 3; i++) {
643 c = &pit->pit_state.channels[i];
644 c->mode = 0xff;
645 c->gate = (i != 2);
646 pit_load_count(pit->kvm, i, 0);
647 }
648 mutex_unlock(&pit->pit_state.lock);
649
650 atomic_set(&pit->pit_state.pending, 0);
651 pit->pit_state.irq_ack = 1;
652 }
653
pit_mask_notifer(struct kvm_irq_mask_notifier * kimn,bool mask)654 static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
655 {
656 struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
657
658 if (!mask) {
659 atomic_set(&pit->pit_state.pending, 0);
660 pit->pit_state.irq_ack = 1;
661 }
662 }
663
664 static const struct kvm_io_device_ops pit_dev_ops = {
665 .read = pit_ioport_read,
666 .write = pit_ioport_write,
667 };
668
669 static const struct kvm_io_device_ops speaker_dev_ops = {
670 .read = speaker_ioport_read,
671 .write = speaker_ioport_write,
672 };
673
674 /* Caller must hold slots_lock */
kvm_create_pit(struct kvm * kvm,u32 flags)675 struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
676 {
677 struct kvm_pit *pit;
678 struct kvm_kpit_state *pit_state;
679 struct pid *pid;
680 pid_t pid_nr;
681 int ret;
682
683 pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
684 if (!pit)
685 return NULL;
686
687 pit->irq_source_id = kvm_request_irq_source_id(kvm);
688 if (pit->irq_source_id < 0) {
689 kfree(pit);
690 return NULL;
691 }
692
693 mutex_init(&pit->pit_state.lock);
694 mutex_lock(&pit->pit_state.lock);
695 spin_lock_init(&pit->pit_state.inject_lock);
696
697 pid = get_pid(task_tgid(current));
698 pid_nr = pid_vnr(pid);
699 put_pid(pid);
700
701 init_kthread_worker(&pit->worker);
702 pit->worker_task = kthread_run(kthread_worker_fn, &pit->worker,
703 "kvm-pit/%d", pid_nr);
704 if (IS_ERR(pit->worker_task)) {
705 mutex_unlock(&pit->pit_state.lock);
706 kvm_free_irq_source_id(kvm, pit->irq_source_id);
707 kfree(pit);
708 return NULL;
709 }
710 init_kthread_work(&pit->expired, pit_do_work);
711
712 kvm->arch.vpit = pit;
713 pit->kvm = kvm;
714
715 pit_state = &pit->pit_state;
716 pit_state->pit = pit;
717 hrtimer_init(&pit_state->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
718 pit_state->irq_ack_notifier.gsi = 0;
719 pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
720 kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
721 pit_state->reinject = true;
722 mutex_unlock(&pit->pit_state.lock);
723
724 kvm_pit_reset(pit);
725
726 pit->mask_notifier.func = pit_mask_notifer;
727 kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
728
729 kvm_iodevice_init(&pit->dev, &pit_dev_ops);
730 ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, KVM_PIT_BASE_ADDRESS,
731 KVM_PIT_MEM_LENGTH, &pit->dev);
732 if (ret < 0)
733 goto fail;
734
735 if (flags & KVM_PIT_SPEAKER_DUMMY) {
736 kvm_iodevice_init(&pit->speaker_dev, &speaker_dev_ops);
737 ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS,
738 KVM_SPEAKER_BASE_ADDRESS, 4,
739 &pit->speaker_dev);
740 if (ret < 0)
741 goto fail_unregister;
742 }
743
744 return pit;
745
746 fail_unregister:
747 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev);
748
749 fail:
750 kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
751 kvm_unregister_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
752 kvm_free_irq_source_id(kvm, pit->irq_source_id);
753 kthread_stop(pit->worker_task);
754 kfree(pit);
755 return NULL;
756 }
757
kvm_free_pit(struct kvm * kvm)758 void kvm_free_pit(struct kvm *kvm)
759 {
760 struct hrtimer *timer;
761
762 if (kvm->arch.vpit) {
763 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &kvm->arch.vpit->dev);
764 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS,
765 &kvm->arch.vpit->speaker_dev);
766 kvm_unregister_irq_mask_notifier(kvm, 0,
767 &kvm->arch.vpit->mask_notifier);
768 kvm_unregister_irq_ack_notifier(kvm,
769 &kvm->arch.vpit->pit_state.irq_ack_notifier);
770 mutex_lock(&kvm->arch.vpit->pit_state.lock);
771 timer = &kvm->arch.vpit->pit_state.timer;
772 hrtimer_cancel(timer);
773 flush_kthread_work(&kvm->arch.vpit->expired);
774 kthread_stop(kvm->arch.vpit->worker_task);
775 kvm_free_irq_source_id(kvm, kvm->arch.vpit->irq_source_id);
776 mutex_unlock(&kvm->arch.vpit->pit_state.lock);
777 kfree(kvm->arch.vpit);
778 }
779 }
780