Merge branch 'fixes-hwmod-regression' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6.git] / arch / x86 / kvm / i8254.c
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 #include <linux/workqueue.h>
38
39 #include "irq.h"
40 #include "i8254.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 */
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
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
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
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->pit_timer.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->pit_timer.timer);
125         elapsed = ps->pit_timer.period - ktime_to_ns(remaining);
126         elapsed = mod_64(elapsed, ps->pit_timer.period);
127
128         return elapsed;
129 }
130
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
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
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
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
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
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->pit_timer.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->pit_timer.pending);
248         else if (value > 0)
249                 /* in this case, we had multiple outstanding pit interrupts
250                  * that we needed to inject.  Reinject
251                  */
252                 queue_work(ps->pit->wq, &ps->pit->expired);
253         ps->irq_ack = 1;
254         spin_unlock(&ps->inject_lock);
255 }
256
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.pit_timer.timer;
266         if (hrtimer_cancel(timer))
267                 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
268 }
269
270 static void destroy_pit_timer(struct kvm_pit *pit)
271 {
272         hrtimer_cancel(&pit->pit_state.pit_timer.timer);
273         cancel_work_sync(&pit->expired);
274 }
275
276 static bool kpit_is_periodic(struct kvm_timer *ktimer)
277 {
278         struct kvm_kpit_state *ps = container_of(ktimer, struct kvm_kpit_state,
279                                                  pit_timer);
280         return ps->is_periodic;
281 }
282
283 static struct kvm_timer_ops kpit_ops = {
284         .is_periodic = kpit_is_periodic,
285 };
286
287 static void pit_do_work(struct work_struct *work)
288 {
289         struct kvm_pit *pit = container_of(work, struct kvm_pit, expired);
290         struct kvm *kvm = pit->kvm;
291         struct kvm_vcpu *vcpu;
292         int i;
293         struct kvm_kpit_state *ps = &pit->pit_state;
294         int inject = 0;
295
296         /* Try to inject pending interrupts when
297          * last one has been acked.
298          */
299         spin_lock(&ps->inject_lock);
300         if (ps->irq_ack) {
301                 ps->irq_ack = 0;
302                 inject = 1;
303         }
304         spin_unlock(&ps->inject_lock);
305         if (inject) {
306                 kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1);
307                 kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0);
308
309                 /*
310                  * Provides NMI watchdog support via Virtual Wire mode.
311                  * The route is: PIT -> PIC -> LVT0 in NMI mode.
312                  *
313                  * Note: Our Virtual Wire implementation is simplified, only
314                  * propagating PIT interrupts to all VCPUs when they have set
315                  * LVT0 to NMI delivery. Other PIC interrupts are just sent to
316                  * VCPU0, and only if its LVT0 is in EXTINT mode.
317                  */
318                 if (kvm->arch.vapics_in_nmi_mode > 0)
319                         kvm_for_each_vcpu(i, vcpu, kvm)
320                                 kvm_apic_nmi_wd_deliver(vcpu);
321         }
322 }
323
324 static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
325 {
326         struct kvm_timer *ktimer = container_of(data, struct kvm_timer, timer);
327         struct kvm_pit *pt = ktimer->kvm->arch.vpit;
328
329         if (ktimer->reinject || !atomic_read(&ktimer->pending)) {
330                 atomic_inc(&ktimer->pending);
331                 queue_work(pt->wq, &pt->expired);
332         }
333
334         if (ktimer->t_ops->is_periodic(ktimer)) {
335                 hrtimer_add_expires_ns(&ktimer->timer, ktimer->period);
336                 return HRTIMER_RESTART;
337         } else
338                 return HRTIMER_NORESTART;
339 }
340
341 static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period)
342 {
343         struct kvm_timer *pt = &ps->pit_timer;
344         s64 interval;
345
346         interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
347
348         pr_debug("create pit timer, interval is %llu nsec\n", interval);
349
350         /* TODO The new value only affected after the retriggered */
351         hrtimer_cancel(&pt->timer);
352         cancel_work_sync(&ps->pit->expired);
353         pt->period = interval;
354         ps->is_periodic = is_period;
355
356         pt->timer.function = pit_timer_fn;
357         pt->t_ops = &kpit_ops;
358         pt->kvm = ps->pit->kvm;
359
360         atomic_set(&pt->pending, 0);
361         ps->irq_ack = 1;
362
363         hrtimer_start(&pt->timer, ktime_add_ns(ktime_get(), interval),
364                       HRTIMER_MODE_ABS);
365 }
366
367 static void pit_load_count(struct kvm *kvm, int channel, u32 val)
368 {
369         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
370
371         WARN_ON(!mutex_is_locked(&ps->lock));
372
373         pr_debug("load_count val is %d, channel is %d\n", val, channel);
374
375         /*
376          * The largest possible initial count is 0; this is equivalent
377          * to 216 for binary counting and 104 for BCD counting.
378          */
379         if (val == 0)
380                 val = 0x10000;
381
382         ps->channels[channel].count = val;
383
384         if (channel != 0) {
385                 ps->channels[channel].count_load_time = ktime_get();
386                 return;
387         }
388
389         /* Two types of timer
390          * mode 1 is one shot, mode 2 is period, otherwise del timer */
391         switch (ps->channels[0].mode) {
392         case 0:
393         case 1:
394         /* FIXME: enhance mode 4 precision */
395         case 4:
396                 if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)) {
397                         create_pit_timer(ps, val, 0);
398                 }
399                 break;
400         case 2:
401         case 3:
402                 if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)){
403                         create_pit_timer(ps, val, 1);
404                 }
405                 break;
406         default:
407                 destroy_pit_timer(kvm->arch.vpit);
408         }
409 }
410
411 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start)
412 {
413         u8 saved_mode;
414         if (hpet_legacy_start) {
415                 /* save existing mode for later reenablement */
416                 saved_mode = kvm->arch.vpit->pit_state.channels[0].mode;
417                 kvm->arch.vpit->pit_state.channels[0].mode = 0xff; /* disable timer */
418                 pit_load_count(kvm, channel, val);
419                 kvm->arch.vpit->pit_state.channels[0].mode = saved_mode;
420         } else {
421                 pit_load_count(kvm, channel, val);
422         }
423 }
424
425 static inline struct kvm_pit *dev_to_pit(struct kvm_io_device *dev)
426 {
427         return container_of(dev, struct kvm_pit, dev);
428 }
429
430 static inline struct kvm_pit *speaker_to_pit(struct kvm_io_device *dev)
431 {
432         return container_of(dev, struct kvm_pit, speaker_dev);
433 }
434
435 static inline int pit_in_range(gpa_t addr)
436 {
437         return ((addr >= KVM_PIT_BASE_ADDRESS) &&
438                 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
439 }
440
441 static int pit_ioport_write(struct kvm_io_device *this,
442                             gpa_t addr, int len, const void *data)
443 {
444         struct kvm_pit *pit = dev_to_pit(this);
445         struct kvm_kpit_state *pit_state = &pit->pit_state;
446         struct kvm *kvm = pit->kvm;
447         int channel, access;
448         struct kvm_kpit_channel_state *s;
449         u32 val = *(u32 *) data;
450         if (!pit_in_range(addr))
451                 return -EOPNOTSUPP;
452
453         val  &= 0xff;
454         addr &= KVM_PIT_CHANNEL_MASK;
455
456         mutex_lock(&pit_state->lock);
457
458         if (val != 0)
459                 pr_debug("write addr is 0x%x, len is %d, val is 0x%x\n",
460                          (unsigned int)addr, len, val);
461
462         if (addr == 3) {
463                 channel = val >> 6;
464                 if (channel == 3) {
465                         /* Read-Back Command. */
466                         for (channel = 0; channel < 3; channel++) {
467                                 s = &pit_state->channels[channel];
468                                 if (val & (2 << channel)) {
469                                         if (!(val & 0x20))
470                                                 pit_latch_count(kvm, channel);
471                                         if (!(val & 0x10))
472                                                 pit_latch_status(kvm, channel);
473                                 }
474                         }
475                 } else {
476                         /* Select Counter <channel>. */
477                         s = &pit_state->channels[channel];
478                         access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
479                         if (access == 0) {
480                                 pit_latch_count(kvm, channel);
481                         } else {
482                                 s->rw_mode = access;
483                                 s->read_state = access;
484                                 s->write_state = access;
485                                 s->mode = (val >> 1) & 7;
486                                 if (s->mode > 5)
487                                         s->mode -= 4;
488                                 s->bcd = val & 1;
489                         }
490                 }
491         } else {
492                 /* Write Count. */
493                 s = &pit_state->channels[addr];
494                 switch (s->write_state) {
495                 default:
496                 case RW_STATE_LSB:
497                         pit_load_count(kvm, addr, val);
498                         break;
499                 case RW_STATE_MSB:
500                         pit_load_count(kvm, addr, val << 8);
501                         break;
502                 case RW_STATE_WORD0:
503                         s->write_latch = val;
504                         s->write_state = RW_STATE_WORD1;
505                         break;
506                 case RW_STATE_WORD1:
507                         pit_load_count(kvm, addr, s->write_latch | (val << 8));
508                         s->write_state = RW_STATE_WORD0;
509                         break;
510                 }
511         }
512
513         mutex_unlock(&pit_state->lock);
514         return 0;
515 }
516
517 static int pit_ioport_read(struct kvm_io_device *this,
518                            gpa_t addr, int len, void *data)
519 {
520         struct kvm_pit *pit = dev_to_pit(this);
521         struct kvm_kpit_state *pit_state = &pit->pit_state;
522         struct kvm *kvm = pit->kvm;
523         int ret, count;
524         struct kvm_kpit_channel_state *s;
525         if (!pit_in_range(addr))
526                 return -EOPNOTSUPP;
527
528         addr &= KVM_PIT_CHANNEL_MASK;
529         if (addr == 3)
530                 return 0;
531
532         s = &pit_state->channels[addr];
533
534         mutex_lock(&pit_state->lock);
535
536         if (s->status_latched) {
537                 s->status_latched = 0;
538                 ret = s->status;
539         } else if (s->count_latched) {
540                 switch (s->count_latched) {
541                 default:
542                 case RW_STATE_LSB:
543                         ret = s->latched_count & 0xff;
544                         s->count_latched = 0;
545                         break;
546                 case RW_STATE_MSB:
547                         ret = s->latched_count >> 8;
548                         s->count_latched = 0;
549                         break;
550                 case RW_STATE_WORD0:
551                         ret = s->latched_count & 0xff;
552                         s->count_latched = RW_STATE_MSB;
553                         break;
554                 }
555         } else {
556                 switch (s->read_state) {
557                 default:
558                 case RW_STATE_LSB:
559                         count = pit_get_count(kvm, addr);
560                         ret = count & 0xff;
561                         break;
562                 case RW_STATE_MSB:
563                         count = pit_get_count(kvm, addr);
564                         ret = (count >> 8) & 0xff;
565                         break;
566                 case RW_STATE_WORD0:
567                         count = pit_get_count(kvm, addr);
568                         ret = count & 0xff;
569                         s->read_state = RW_STATE_WORD1;
570                         break;
571                 case RW_STATE_WORD1:
572                         count = pit_get_count(kvm, addr);
573                         ret = (count >> 8) & 0xff;
574                         s->read_state = RW_STATE_WORD0;
575                         break;
576                 }
577         }
578
579         if (len > sizeof(ret))
580                 len = sizeof(ret);
581         memcpy(data, (char *)&ret, len);
582
583         mutex_unlock(&pit_state->lock);
584         return 0;
585 }
586
587 static int speaker_ioport_write(struct kvm_io_device *this,
588                                 gpa_t addr, int len, const void *data)
589 {
590         struct kvm_pit *pit = speaker_to_pit(this);
591         struct kvm_kpit_state *pit_state = &pit->pit_state;
592         struct kvm *kvm = pit->kvm;
593         u32 val = *(u32 *) data;
594         if (addr != KVM_SPEAKER_BASE_ADDRESS)
595                 return -EOPNOTSUPP;
596
597         mutex_lock(&pit_state->lock);
598         pit_state->speaker_data_on = (val >> 1) & 1;
599         pit_set_gate(kvm, 2, val & 1);
600         mutex_unlock(&pit_state->lock);
601         return 0;
602 }
603
604 static int speaker_ioport_read(struct kvm_io_device *this,
605                                gpa_t addr, int len, void *data)
606 {
607         struct kvm_pit *pit = speaker_to_pit(this);
608         struct kvm_kpit_state *pit_state = &pit->pit_state;
609         struct kvm *kvm = pit->kvm;
610         unsigned int refresh_clock;
611         int ret;
612         if (addr != KVM_SPEAKER_BASE_ADDRESS)
613                 return -EOPNOTSUPP;
614
615         /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
616         refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
617
618         mutex_lock(&pit_state->lock);
619         ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
620                 (pit_get_out(kvm, 2) << 5) | (refresh_clock << 4));
621         if (len > sizeof(ret))
622                 len = sizeof(ret);
623         memcpy(data, (char *)&ret, len);
624         mutex_unlock(&pit_state->lock);
625         return 0;
626 }
627
628 void kvm_pit_reset(struct kvm_pit *pit)
629 {
630         int i;
631         struct kvm_kpit_channel_state *c;
632
633         mutex_lock(&pit->pit_state.lock);
634         pit->pit_state.flags = 0;
635         for (i = 0; i < 3; i++) {
636                 c = &pit->pit_state.channels[i];
637                 c->mode = 0xff;
638                 c->gate = (i != 2);
639                 pit_load_count(pit->kvm, i, 0);
640         }
641         mutex_unlock(&pit->pit_state.lock);
642
643         atomic_set(&pit->pit_state.pit_timer.pending, 0);
644         pit->pit_state.irq_ack = 1;
645 }
646
647 static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
648 {
649         struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
650
651         if (!mask) {
652                 atomic_set(&pit->pit_state.pit_timer.pending, 0);
653                 pit->pit_state.irq_ack = 1;
654         }
655 }
656
657 static const struct kvm_io_device_ops pit_dev_ops = {
658         .read     = pit_ioport_read,
659         .write    = pit_ioport_write,
660 };
661
662 static const struct kvm_io_device_ops speaker_dev_ops = {
663         .read     = speaker_ioport_read,
664         .write    = speaker_ioport_write,
665 };
666
667 /* Caller must hold slots_lock */
668 struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
669 {
670         struct kvm_pit *pit;
671         struct kvm_kpit_state *pit_state;
672         int ret;
673
674         pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
675         if (!pit)
676                 return NULL;
677
678         pit->irq_source_id = kvm_request_irq_source_id(kvm);
679         if (pit->irq_source_id < 0) {
680                 kfree(pit);
681                 return NULL;
682         }
683
684         mutex_init(&pit->pit_state.lock);
685         mutex_lock(&pit->pit_state.lock);
686         spin_lock_init(&pit->pit_state.inject_lock);
687
688         pit->wq = create_singlethread_workqueue("kvm-pit-wq");
689         if (!pit->wq) {
690                 mutex_unlock(&pit->pit_state.lock);
691                 kvm_free_irq_source_id(kvm, pit->irq_source_id);
692                 kfree(pit);
693                 return NULL;
694         }
695         INIT_WORK(&pit->expired, pit_do_work);
696
697         kvm->arch.vpit = pit;
698         pit->kvm = kvm;
699
700         pit_state = &pit->pit_state;
701         pit_state->pit = pit;
702         hrtimer_init(&pit_state->pit_timer.timer,
703                      CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
704         pit_state->irq_ack_notifier.gsi = 0;
705         pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
706         kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
707         pit_state->pit_timer.reinject = true;
708         mutex_unlock(&pit->pit_state.lock);
709
710         kvm_pit_reset(pit);
711
712         pit->mask_notifier.func = pit_mask_notifer;
713         kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
714
715         kvm_iodevice_init(&pit->dev, &pit_dev_ops);
716         ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, KVM_PIT_BASE_ADDRESS,
717                                       KVM_PIT_MEM_LENGTH, &pit->dev);
718         if (ret < 0)
719                 goto fail;
720
721         if (flags & KVM_PIT_SPEAKER_DUMMY) {
722                 kvm_iodevice_init(&pit->speaker_dev, &speaker_dev_ops);
723                 ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS,
724                                               KVM_SPEAKER_BASE_ADDRESS, 4,
725                                               &pit->speaker_dev);
726                 if (ret < 0)
727                         goto fail_unregister;
728         }
729
730         return pit;
731
732 fail_unregister:
733         kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev);
734
735 fail:
736         kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
737         kvm_unregister_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
738         kvm_free_irq_source_id(kvm, pit->irq_source_id);
739         destroy_workqueue(pit->wq);
740         kfree(pit);
741         return NULL;
742 }
743
744 void kvm_free_pit(struct kvm *kvm)
745 {
746         struct hrtimer *timer;
747
748         if (kvm->arch.vpit) {
749                 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &kvm->arch.vpit->dev);
750                 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS,
751                                               &kvm->arch.vpit->speaker_dev);
752                 kvm_unregister_irq_mask_notifier(kvm, 0,
753                                                &kvm->arch.vpit->mask_notifier);
754                 kvm_unregister_irq_ack_notifier(kvm,
755                                 &kvm->arch.vpit->pit_state.irq_ack_notifier);
756                 mutex_lock(&kvm->arch.vpit->pit_state.lock);
757                 timer = &kvm->arch.vpit->pit_state.pit_timer.timer;
758                 hrtimer_cancel(timer);
759                 cancel_work_sync(&kvm->arch.vpit->expired);
760                 kvm_free_irq_source_id(kvm, kvm->arch.vpit->irq_source_id);
761                 mutex_unlock(&kvm->arch.vpit->pit_state.lock);
762                 destroy_workqueue(kvm->arch.vpit->wq);
763                 kfree(kvm->arch.vpit);
764         }
765 }