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 "ioapic.h"
39 #include "irq.h"
40 #include "i8254.h"
41 #include "x86.h"
42
43 #ifndef CONFIG_X86_64
44 #define mod_64(x, y) ((x) - (y) * div64_u64(x, y))
45 #else
46 #define mod_64(x, y) ((x) % (y))
47 #endif
48
49 #define RW_STATE_LSB 1
50 #define RW_STATE_MSB 2
51 #define RW_STATE_WORD0 3
52 #define RW_STATE_WORD1 4
53
54 /* Compute with 96 bit intermediate result: (a*b)/c */
muldiv64(u64 a,u32 b,u32 c)55 static u64 muldiv64(u64 a, u32 b, u32 c)
56 {
57 union {
58 u64 ll;
59 struct {
60 u32 low, high;
61 } l;
62 } u, res;
63 u64 rl, rh;
64
65 u.ll = a;
66 rl = (u64)u.l.low * (u64)b;
67 rh = (u64)u.l.high * (u64)b;
68 rh += (rl >> 32);
69 res.l.high = div64_u64(rh, c);
70 res.l.low = div64_u64(((mod_64(rh, c) << 32) + (rl & 0xffffffff)), c);
71 return res.ll;
72 }
73
pit_set_gate(struct kvm * kvm,int channel,u32 val)74 static void pit_set_gate(struct kvm *kvm, int channel, u32 val)
75 {
76 struct kvm_kpit_channel_state *c =
77 &kvm->arch.vpit->pit_state.channels[channel];
78
79 WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
80
81 switch (c->mode) {
82 default:
83 case 0:
84 case 4:
85 /* XXX: just disable/enable counting */
86 break;
87 case 1:
88 case 2:
89 case 3:
90 case 5:
91 /* Restart counting on rising edge. */
92 if (c->gate < val)
93 c->count_load_time = ktime_get();
94 break;
95 }
96
97 c->gate = val;
98 }
99
pit_get_gate(struct kvm * kvm,int channel)100 static int pit_get_gate(struct kvm *kvm, int channel)
101 {
102 WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
103
104 return kvm->arch.vpit->pit_state.channels[channel].gate;
105 }
106
__kpit_elapsed(struct kvm * kvm)107 static s64 __kpit_elapsed(struct kvm *kvm)
108 {
109 s64 elapsed;
110 ktime_t remaining;
111 struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
112
113 if (!ps->period)
114 return 0;
115
116 /*
117 * The Counter does not stop when it reaches zero. In
118 * Modes 0, 1, 4, and 5 the Counter ``wraps around'' to
119 * the highest count, either FFFF hex for binary counting
120 * or 9999 for BCD counting, and continues counting.
121 * Modes 2 and 3 are periodic; the Counter reloads
122 * itself with the initial count and continues counting
123 * from there.
124 */
125 remaining = hrtimer_get_remaining(&ps->timer);
126 elapsed = ps->period - ktime_to_ns(remaining);
127
128 return elapsed;
129 }
130
kpit_elapsed(struct kvm * kvm,struct kvm_kpit_channel_state * c,int channel)131 static s64 kpit_elapsed(struct kvm *kvm, struct kvm_kpit_channel_state *c,
132 int channel)
133 {
134 if (channel == 0)
135 return __kpit_elapsed(kvm);
136
137 return ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));
138 }
139
pit_get_count(struct kvm * kvm,int channel)140 static int pit_get_count(struct kvm *kvm, int channel)
141 {
142 struct kvm_kpit_channel_state *c =
143 &kvm->arch.vpit->pit_state.channels[channel];
144 s64 d, t;
145 int counter;
146
147 WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
148
149 t = kpit_elapsed(kvm, c, channel);
150 d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
151
152 switch (c->mode) {
153 case 0:
154 case 1:
155 case 4:
156 case 5:
157 counter = (c->count - d) & 0xffff;
158 break;
159 case 3:
160 /* XXX: may be incorrect for odd counts */
161 counter = c->count - (mod_64((2 * d), c->count));
162 break;
163 default:
164 counter = c->count - mod_64(d, c->count);
165 break;
166 }
167 return counter;
168 }
169
pit_get_out(struct kvm * kvm,int channel)170 static int pit_get_out(struct kvm *kvm, int channel)
171 {
172 struct kvm_kpit_channel_state *c =
173 &kvm->arch.vpit->pit_state.channels[channel];
174 s64 d, t;
175 int out;
176
177 WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
178
179 t = kpit_elapsed(kvm, c, channel);
180 d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
181
182 switch (c->mode) {
183 default:
184 case 0:
185 out = (d >= c->count);
186 break;
187 case 1:
188 out = (d < c->count);
189 break;
190 case 2:
191 out = ((mod_64(d, c->count) == 0) && (d != 0));
192 break;
193 case 3:
194 out = (mod_64(d, c->count) < ((c->count + 1) >> 1));
195 break;
196 case 4:
197 case 5:
198 out = (d == c->count);
199 break;
200 }
201
202 return out;
203 }
204
pit_latch_count(struct kvm * kvm,int channel)205 static void pit_latch_count(struct kvm *kvm, int channel)
206 {
207 struct kvm_kpit_channel_state *c =
208 &kvm->arch.vpit->pit_state.channels[channel];
209
210 WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
211
212 if (!c->count_latched) {
213 c->latched_count = pit_get_count(kvm, channel);
214 c->count_latched = c->rw_mode;
215 }
216 }
217
pit_latch_status(struct kvm * kvm,int channel)218 static void pit_latch_status(struct kvm *kvm, int channel)
219 {
220 struct kvm_kpit_channel_state *c =
221 &kvm->arch.vpit->pit_state.channels[channel];
222
223 WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
224
225 if (!c->status_latched) {
226 /* TODO: Return NULL COUNT (bit 6). */
227 c->status = ((pit_get_out(kvm, channel) << 7) |
228 (c->rw_mode << 4) |
229 (c->mode << 1) |
230 c->bcd);
231 c->status_latched = 1;
232 }
233 }
234
kvm_pit_ack_irq(struct kvm_irq_ack_notifier * kian)235 static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
236 {
237 struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
238 irq_ack_notifier);
239 int value;
240
241 spin_lock(&ps->inject_lock);
242 value = atomic_dec_return(&ps->pending);
243 if (value < 0)
244 /* spurious acks can be generated if, for example, the
245 * PIC is being reset. Handle it gracefully here
246 */
247 atomic_inc(&ps->pending);
248 else if (value > 0 && ps->reinject)
249 /* in this case, we had multiple outstanding pit interrupts
250 * that we needed to inject. Reinject
251 */
252 queue_kthread_work(&ps->pit->worker, &ps->pit->expired);
253 ps->irq_ack = 1;
254 spin_unlock(&ps->inject_lock);
255 }
256
__kvm_migrate_pit_timer(struct kvm_vcpu * vcpu)257 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
258 {
259 struct kvm_pit *pit = vcpu->kvm->arch.vpit;
260 struct hrtimer *timer;
261
262 if (!kvm_vcpu_is_bsp(vcpu) || !pit)
263 return;
264
265 timer = &pit->pit_state.timer;
266 mutex_lock(&pit->pit_state.lock);
267 if (hrtimer_cancel(timer))
268 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
269 mutex_unlock(&pit->pit_state.lock);
270 }
271
destroy_pit_timer(struct kvm_pit * pit)272 static void destroy_pit_timer(struct kvm_pit *pit)
273 {
274 hrtimer_cancel(&pit->pit_state.timer);
275 flush_kthread_work(&pit->expired);
276 }
277
pit_do_work(struct kthread_work * work)278 static void pit_do_work(struct kthread_work *work)
279 {
280 struct kvm_pit *pit = container_of(work, struct kvm_pit, expired);
281 struct kvm *kvm = pit->kvm;
282 struct kvm_vcpu *vcpu;
283 int i;
284 struct kvm_kpit_state *ps = &pit->pit_state;
285 int inject = 0;
286
287 /* Try to inject pending interrupts when
288 * last one has been acked.
289 */
290 spin_lock(&ps->inject_lock);
291 if (!ps->reinject)
292 inject = 1;
293 else if (ps->irq_ack) {
294 ps->irq_ack = 0;
295 inject = 1;
296 }
297 spin_unlock(&ps->inject_lock);
298 if (inject) {
299 kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1, false);
300 kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0, false);
301
302 /*
303 * Provides NMI watchdog support via Virtual Wire mode.
304 * The route is: PIT -> PIC -> LVT0 in NMI mode.
305 *
306 * Note: Our Virtual Wire implementation is simplified, only
307 * propagating PIT interrupts to all VCPUs when they have set
308 * LVT0 to NMI delivery. Other PIC interrupts are just sent to
309 * VCPU0, and only if its LVT0 is in EXTINT mode.
310 */
311 if (atomic_read(&kvm->arch.vapics_in_nmi_mode) > 0)
312 kvm_for_each_vcpu(i, vcpu, kvm)
313 kvm_apic_nmi_wd_deliver(vcpu);
314 }
315 }
316
pit_timer_fn(struct hrtimer * data)317 static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
318 {
319 struct kvm_kpit_state *ps = container_of(data, struct kvm_kpit_state, timer);
320 struct kvm_pit *pt = ps->kvm->arch.vpit;
321
322 if (ps->reinject)
323 atomic_inc(&ps->pending);
324
325 queue_kthread_work(&pt->worker, &pt->expired);
326
327 if (ps->is_periodic) {
328 hrtimer_add_expires_ns(&ps->timer, ps->period);
329 return HRTIMER_RESTART;
330 } else
331 return HRTIMER_NORESTART;
332 }
333
create_pit_timer(struct kvm * kvm,u32 val,int is_period)334 static void create_pit_timer(struct kvm *kvm, u32 val, int is_period)
335 {
336 struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
337 s64 interval;
338
339 if (!ioapic_in_kernel(kvm) ||
340 ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)
341 return;
342
343 interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
344
345 pr_debug("create pit timer, interval is %llu nsec\n", interval);
346
347 /* TODO The new value only affected after the retriggered */
348 hrtimer_cancel(&ps->timer);
349 flush_kthread_work(&ps->pit->expired);
350 ps->period = interval;
351 ps->is_periodic = is_period;
352
353 ps->timer.function = pit_timer_fn;
354 ps->kvm = ps->pit->kvm;
355
356 atomic_set(&ps->pending, 0);
357 ps->irq_ack = 1;
358
359 /*
360 * Do not allow the guest to program periodic timers with small
361 * interval, since the hrtimers are not throttled by the host
362 * scheduler.
363 */
364 if (ps->is_periodic) {
365 s64 min_period = min_timer_period_us * 1000LL;
366
367 if (ps->period < min_period) {
368 pr_info_ratelimited(
369 "kvm: requested %lld ns "
370 "i8254 timer period limited to %lld ns\n",
371 ps->period, min_period);
372 ps->period = min_period;
373 }
374 }
375
376 hrtimer_start(&ps->timer, ktime_add_ns(ktime_get(), interval),
377 HRTIMER_MODE_ABS);
378 }
379
pit_load_count(struct kvm * kvm,int channel,u32 val)380 static void pit_load_count(struct kvm *kvm, int channel, u32 val)
381 {
382 struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
383
384 WARN_ON(!mutex_is_locked(&ps->lock));
385
386 pr_debug("load_count val is %d, channel is %d\n", val, channel);
387
388 /*
389 * The largest possible initial count is 0; this is equivalent
390 * to 216 for binary counting and 104 for BCD counting.
391 */
392 if (val == 0)
393 val = 0x10000;
394
395 ps->channels[channel].count = val;
396
397 if (channel != 0) {
398 ps->channels[channel].count_load_time = ktime_get();
399 return;
400 }
401
402 /* Two types of timer
403 * mode 1 is one shot, mode 2 is period, otherwise del timer */
404 switch (ps->channels[0].mode) {
405 case 0:
406 case 1:
407 /* FIXME: enhance mode 4 precision */
408 case 4:
409 create_pit_timer(kvm, val, 0);
410 break;
411 case 2:
412 case 3:
413 create_pit_timer(kvm, val, 1);
414 break;
415 default:
416 destroy_pit_timer(kvm->arch.vpit);
417 }
418 }
419
kvm_pit_load_count(struct kvm * kvm,int channel,u32 val,int hpet_legacy_start)420 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start)
421 {
422 u8 saved_mode;
423 if (hpet_legacy_start) {
424 /* save existing mode for later reenablement */
425 WARN_ON(channel != 0);
426 saved_mode = kvm->arch.vpit->pit_state.channels[0].mode;
427 kvm->arch.vpit->pit_state.channels[0].mode = 0xff; /* disable timer */
428 pit_load_count(kvm, channel, val);
429 kvm->arch.vpit->pit_state.channels[0].mode = saved_mode;
430 } else {
431 pit_load_count(kvm, channel, val);
432 }
433 }
434
dev_to_pit(struct kvm_io_device * dev)435 static inline struct kvm_pit *dev_to_pit(struct kvm_io_device *dev)
436 {
437 return container_of(dev, struct kvm_pit, dev);
438 }
439
speaker_to_pit(struct kvm_io_device * dev)440 static inline struct kvm_pit *speaker_to_pit(struct kvm_io_device *dev)
441 {
442 return container_of(dev, struct kvm_pit, speaker_dev);
443 }
444
pit_in_range(gpa_t addr)445 static inline int pit_in_range(gpa_t addr)
446 {
447 return ((addr >= KVM_PIT_BASE_ADDRESS) &&
448 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
449 }
450
pit_ioport_write(struct kvm_vcpu * vcpu,struct kvm_io_device * this,gpa_t addr,int len,const void * data)451 static int pit_ioport_write(struct kvm_vcpu *vcpu,
452 struct kvm_io_device *this,
453 gpa_t addr, int len, const void *data)
454 {
455 struct kvm_pit *pit = dev_to_pit(this);
456 struct kvm_kpit_state *pit_state = &pit->pit_state;
457 struct kvm *kvm = pit->kvm;
458 int channel, access;
459 struct kvm_kpit_channel_state *s;
460 u32 val = *(u32 *) data;
461 if (!pit_in_range(addr))
462 return -EOPNOTSUPP;
463
464 val &= 0xff;
465 addr &= KVM_PIT_CHANNEL_MASK;
466
467 mutex_lock(&pit_state->lock);
468
469 if (val != 0)
470 pr_debug("write addr is 0x%x, len is %d, val is 0x%x\n",
471 (unsigned int)addr, len, val);
472
473 if (addr == 3) {
474 channel = val >> 6;
475 if (channel == 3) {
476 /* Read-Back Command. */
477 for (channel = 0; channel < 3; channel++) {
478 s = &pit_state->channels[channel];
479 if (val & (2 << channel)) {
480 if (!(val & 0x20))
481 pit_latch_count(kvm, channel);
482 if (!(val & 0x10))
483 pit_latch_status(kvm, channel);
484 }
485 }
486 } else {
487 /* Select Counter <channel>. */
488 s = &pit_state->channels[channel];
489 access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
490 if (access == 0) {
491 pit_latch_count(kvm, channel);
492 } else {
493 s->rw_mode = access;
494 s->read_state = access;
495 s->write_state = access;
496 s->mode = (val >> 1) & 7;
497 if (s->mode > 5)
498 s->mode -= 4;
499 s->bcd = val & 1;
500 }
501 }
502 } else {
503 /* Write Count. */
504 s = &pit_state->channels[addr];
505 switch (s->write_state) {
506 default:
507 case RW_STATE_LSB:
508 pit_load_count(kvm, addr, val);
509 break;
510 case RW_STATE_MSB:
511 pit_load_count(kvm, addr, val << 8);
512 break;
513 case RW_STATE_WORD0:
514 s->write_latch = val;
515 s->write_state = RW_STATE_WORD1;
516 break;
517 case RW_STATE_WORD1:
518 pit_load_count(kvm, addr, s->write_latch | (val << 8));
519 s->write_state = RW_STATE_WORD0;
520 break;
521 }
522 }
523
524 mutex_unlock(&pit_state->lock);
525 return 0;
526 }
527
pit_ioport_read(struct kvm_vcpu * vcpu,struct kvm_io_device * this,gpa_t addr,int len,void * data)528 static int pit_ioport_read(struct kvm_vcpu *vcpu,
529 struct kvm_io_device *this,
530 gpa_t addr, int len, void *data)
531 {
532 struct kvm_pit *pit = dev_to_pit(this);
533 struct kvm_kpit_state *pit_state = &pit->pit_state;
534 struct kvm *kvm = pit->kvm;
535 int ret, count;
536 struct kvm_kpit_channel_state *s;
537 if (!pit_in_range(addr))
538 return -EOPNOTSUPP;
539
540 addr &= KVM_PIT_CHANNEL_MASK;
541 if (addr == 3)
542 return 0;
543
544 s = &pit_state->channels[addr];
545
546 mutex_lock(&pit_state->lock);
547
548 if (s->status_latched) {
549 s->status_latched = 0;
550 ret = s->status;
551 } else if (s->count_latched) {
552 switch (s->count_latched) {
553 default:
554 case RW_STATE_LSB:
555 ret = s->latched_count & 0xff;
556 s->count_latched = 0;
557 break;
558 case RW_STATE_MSB:
559 ret = s->latched_count >> 8;
560 s->count_latched = 0;
561 break;
562 case RW_STATE_WORD0:
563 ret = s->latched_count & 0xff;
564 s->count_latched = RW_STATE_MSB;
565 break;
566 }
567 } else {
568 switch (s->read_state) {
569 default:
570 case RW_STATE_LSB:
571 count = pit_get_count(kvm, addr);
572 ret = count & 0xff;
573 break;
574 case RW_STATE_MSB:
575 count = pit_get_count(kvm, addr);
576 ret = (count >> 8) & 0xff;
577 break;
578 case RW_STATE_WORD0:
579 count = pit_get_count(kvm, addr);
580 ret = count & 0xff;
581 s->read_state = RW_STATE_WORD1;
582 break;
583 case RW_STATE_WORD1:
584 count = pit_get_count(kvm, addr);
585 ret = (count >> 8) & 0xff;
586 s->read_state = RW_STATE_WORD0;
587 break;
588 }
589 }
590
591 if (len > sizeof(ret))
592 len = sizeof(ret);
593 memcpy(data, (char *)&ret, len);
594
595 mutex_unlock(&pit_state->lock);
596 return 0;
597 }
598
speaker_ioport_write(struct kvm_vcpu * vcpu,struct kvm_io_device * this,gpa_t addr,int len,const void * data)599 static int speaker_ioport_write(struct kvm_vcpu *vcpu,
600 struct kvm_io_device *this,
601 gpa_t addr, int len, const void *data)
602 {
603 struct kvm_pit *pit = speaker_to_pit(this);
604 struct kvm_kpit_state *pit_state = &pit->pit_state;
605 struct kvm *kvm = pit->kvm;
606 u32 val = *(u32 *) data;
607 if (addr != KVM_SPEAKER_BASE_ADDRESS)
608 return -EOPNOTSUPP;
609
610 mutex_lock(&pit_state->lock);
611 pit_state->speaker_data_on = (val >> 1) & 1;
612 pit_set_gate(kvm, 2, val & 1);
613 mutex_unlock(&pit_state->lock);
614 return 0;
615 }
616
speaker_ioport_read(struct kvm_vcpu * vcpu,struct kvm_io_device * this,gpa_t addr,int len,void * data)617 static int speaker_ioport_read(struct kvm_vcpu *vcpu,
618 struct kvm_io_device *this,
619 gpa_t addr, int len, void *data)
620 {
621 struct kvm_pit *pit = speaker_to_pit(this);
622 struct kvm_kpit_state *pit_state = &pit->pit_state;
623 struct kvm *kvm = pit->kvm;
624 unsigned int refresh_clock;
625 int ret;
626 if (addr != KVM_SPEAKER_BASE_ADDRESS)
627 return -EOPNOTSUPP;
628
629 /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
630 refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
631
632 mutex_lock(&pit_state->lock);
633 ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
634 (pit_get_out(kvm, 2) << 5) | (refresh_clock << 4));
635 if (len > sizeof(ret))
636 len = sizeof(ret);
637 memcpy(data, (char *)&ret, len);
638 mutex_unlock(&pit_state->lock);
639 return 0;
640 }
641
kvm_pit_reset(struct kvm_pit * pit)642 void kvm_pit_reset(struct kvm_pit *pit)
643 {
644 int i;
645 struct kvm_kpit_channel_state *c;
646
647 mutex_lock(&pit->pit_state.lock);
648 pit->pit_state.flags = 0;
649 for (i = 0; i < 3; i++) {
650 c = &pit->pit_state.channels[i];
651 c->mode = 0xff;
652 c->gate = (i != 2);
653 pit_load_count(pit->kvm, i, 0);
654 }
655 mutex_unlock(&pit->pit_state.lock);
656
657 atomic_set(&pit->pit_state.pending, 0);
658 pit->pit_state.irq_ack = 1;
659 }
660
pit_mask_notifer(struct kvm_irq_mask_notifier * kimn,bool mask)661 static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
662 {
663 struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
664
665 if (!mask) {
666 atomic_set(&pit->pit_state.pending, 0);
667 pit->pit_state.irq_ack = 1;
668 }
669 }
670
671 static const struct kvm_io_device_ops pit_dev_ops = {
672 .read = pit_ioport_read,
673 .write = pit_ioport_write,
674 };
675
676 static const struct kvm_io_device_ops speaker_dev_ops = {
677 .read = speaker_ioport_read,
678 .write = speaker_ioport_write,
679 };
680
kvm_create_pit(struct kvm * kvm,u32 flags)681 struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
682 {
683 struct kvm_pit *pit;
684 struct kvm_kpit_state *pit_state;
685 struct pid *pid;
686 pid_t pid_nr;
687 int ret;
688
689 pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
690 if (!pit)
691 return NULL;
692
693 pit->irq_source_id = kvm_request_irq_source_id(kvm);
694 if (pit->irq_source_id < 0) {
695 kfree(pit);
696 return NULL;
697 }
698
699 mutex_init(&pit->pit_state.lock);
700 mutex_lock(&pit->pit_state.lock);
701 spin_lock_init(&pit->pit_state.inject_lock);
702
703 pid = get_pid(task_tgid(current));
704 pid_nr = pid_vnr(pid);
705 put_pid(pid);
706
707 init_kthread_worker(&pit->worker);
708 pit->worker_task = kthread_run(kthread_worker_fn, &pit->worker,
709 "kvm-pit/%d", pid_nr);
710 if (IS_ERR(pit->worker_task)) {
711 mutex_unlock(&pit->pit_state.lock);
712 kvm_free_irq_source_id(kvm, pit->irq_source_id);
713 kfree(pit);
714 return NULL;
715 }
716 init_kthread_work(&pit->expired, pit_do_work);
717
718 kvm->arch.vpit = pit;
719 pit->kvm = kvm;
720
721 pit_state = &pit->pit_state;
722 pit_state->pit = pit;
723 hrtimer_init(&pit_state->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
724 pit_state->irq_ack_notifier.gsi = 0;
725 pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
726 kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
727 pit_state->reinject = true;
728 mutex_unlock(&pit->pit_state.lock);
729
730 kvm_pit_reset(pit);
731
732 pit->mask_notifier.func = pit_mask_notifer;
733 kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
734
735 mutex_lock(&kvm->slots_lock);
736 kvm_iodevice_init(&pit->dev, &pit_dev_ops);
737 ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, KVM_PIT_BASE_ADDRESS,
738 KVM_PIT_MEM_LENGTH, &pit->dev);
739 if (ret < 0)
740 goto fail;
741
742 if (flags & KVM_PIT_SPEAKER_DUMMY) {
743 kvm_iodevice_init(&pit->speaker_dev, &speaker_dev_ops);
744 ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS,
745 KVM_SPEAKER_BASE_ADDRESS, 4,
746 &pit->speaker_dev);
747 if (ret < 0)
748 goto fail_unregister;
749 }
750 mutex_unlock(&kvm->slots_lock);
751
752 return pit;
753
754 fail_unregister:
755 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev);
756 fail:
757 mutex_unlock(&kvm->slots_lock);
758 kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
759 kvm_unregister_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
760 kvm_free_irq_source_id(kvm, pit->irq_source_id);
761 kthread_stop(pit->worker_task);
762 kfree(pit);
763 return NULL;
764 }
765
kvm_free_pit(struct kvm * kvm)766 void kvm_free_pit(struct kvm *kvm)
767 {
768 struct hrtimer *timer;
769
770 if (kvm->arch.vpit) {
771 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &kvm->arch.vpit->dev);
772 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS,
773 &kvm->arch.vpit->speaker_dev);
774 kvm_unregister_irq_mask_notifier(kvm, 0,
775 &kvm->arch.vpit->mask_notifier);
776 kvm_unregister_irq_ack_notifier(kvm,
777 &kvm->arch.vpit->pit_state.irq_ack_notifier);
778 mutex_lock(&kvm->arch.vpit->pit_state.lock);
779 timer = &kvm->arch.vpit->pit_state.timer;
780 hrtimer_cancel(timer);
781 flush_kthread_work(&kvm->arch.vpit->expired);
782 kthread_stop(kvm->arch.vpit->worker_task);
783 kvm_free_irq_source_id(kvm, kvm->arch.vpit->irq_source_id);
784 mutex_unlock(&kvm->arch.vpit->pit_state.lock);
785 kfree(kvm->arch.vpit);
786 }
787 }
788