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TOMOYO Linux Cross Reference
Linux/arch/x86/kvm/i8254.c

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  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 static void pit_set_gate(struct kvm_pit *pit, int channel, u32 val)
 55 {
 56         struct kvm_kpit_channel_state *c = &pit->pit_state.channels[channel];
 57 
 58         switch (c->mode) {
 59         default:
 60         case 0:
 61         case 4:
 62                 /* XXX: just disable/enable counting */
 63                 break;
 64         case 1:
 65         case 2:
 66         case 3:
 67         case 5:
 68                 /* Restart counting on rising edge. */
 69                 if (c->gate < val)
 70                         c->count_load_time = ktime_get();
 71                 break;
 72         }
 73 
 74         c->gate = val;
 75 }
 76 
 77 static int pit_get_gate(struct kvm_pit *pit, int channel)
 78 {
 79         return pit->pit_state.channels[channel].gate;
 80 }
 81 
 82 static s64 __kpit_elapsed(struct kvm_pit *pit)
 83 {
 84         s64 elapsed;
 85         ktime_t remaining;
 86         struct kvm_kpit_state *ps = &pit->pit_state;
 87 
 88         if (!ps->period)
 89                 return 0;
 90 
 91         /*
 92          * The Counter does not stop when it reaches zero. In
 93          * Modes 0, 1, 4, and 5 the Counter ``wraps around'' to
 94          * the highest count, either FFFF hex for binary counting
 95          * or 9999 for BCD counting, and continues counting.
 96          * Modes 2 and 3 are periodic; the Counter reloads
 97          * itself with the initial count and continues counting
 98          * from there.
 99          */
100         remaining = hrtimer_get_remaining(&ps->timer);
101         elapsed = ps->period - ktime_to_ns(remaining);
102 
103         return elapsed;
104 }
105 
106 static s64 kpit_elapsed(struct kvm_pit *pit, struct kvm_kpit_channel_state *c,
107                         int channel)
108 {
109         if (channel == 0)
110                 return __kpit_elapsed(pit);
111 
112         return ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));
113 }
114 
115 static int pit_get_count(struct kvm_pit *pit, int channel)
116 {
117         struct kvm_kpit_channel_state *c = &pit->pit_state.channels[channel];
118         s64 d, t;
119         int counter;
120 
121         t = kpit_elapsed(pit, c, channel);
122         d = mul_u64_u32_div(t, KVM_PIT_FREQ, NSEC_PER_SEC);
123 
124         switch (c->mode) {
125         case 0:
126         case 1:
127         case 4:
128         case 5:
129                 counter = (c->count - d) & 0xffff;
130                 break;
131         case 3:
132                 /* XXX: may be incorrect for odd counts */
133                 counter = c->count - (mod_64((2 * d), c->count));
134                 break;
135         default:
136                 counter = c->count - mod_64(d, c->count);
137                 break;
138         }
139         return counter;
140 }
141 
142 static int pit_get_out(struct kvm_pit *pit, int channel)
143 {
144         struct kvm_kpit_channel_state *c = &pit->pit_state.channels[channel];
145         s64 d, t;
146         int out;
147 
148         t = kpit_elapsed(pit, c, channel);
149         d = mul_u64_u32_div(t, KVM_PIT_FREQ, NSEC_PER_SEC);
150 
151         switch (c->mode) {
152         default:
153         case 0:
154                 out = (d >= c->count);
155                 break;
156         case 1:
157                 out = (d < c->count);
158                 break;
159         case 2:
160                 out = ((mod_64(d, c->count) == 0) && (d != 0));
161                 break;
162         case 3:
163                 out = (mod_64(d, c->count) < ((c->count + 1) >> 1));
164                 break;
165         case 4:
166         case 5:
167                 out = (d == c->count);
168                 break;
169         }
170 
171         return out;
172 }
173 
174 static void pit_latch_count(struct kvm_pit *pit, int channel)
175 {
176         struct kvm_kpit_channel_state *c = &pit->pit_state.channels[channel];
177 
178         if (!c->count_latched) {
179                 c->latched_count = pit_get_count(pit, channel);
180                 c->count_latched = c->rw_mode;
181         }
182 }
183 
184 static void pit_latch_status(struct kvm_pit *pit, int channel)
185 {
186         struct kvm_kpit_channel_state *c = &pit->pit_state.channels[channel];
187 
188         if (!c->status_latched) {
189                 /* TODO: Return NULL COUNT (bit 6). */
190                 c->status = ((pit_get_out(pit, channel) << 7) |
191                                 (c->rw_mode << 4) |
192                                 (c->mode << 1) |
193                                 c->bcd);
194                 c->status_latched = 1;
195         }
196 }
197 
198 static inline struct kvm_pit *pit_state_to_pit(struct kvm_kpit_state *ps)
199 {
200         return container_of(ps, struct kvm_pit, pit_state);
201 }
202 
203 static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
204 {
205         struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
206                                                  irq_ack_notifier);
207         struct kvm_pit *pit = pit_state_to_pit(ps);
208 
209         atomic_set(&ps->irq_ack, 1);
210         /* irq_ack should be set before pending is read.  Order accesses with
211          * inc(pending) in pit_timer_fn and xchg(irq_ack, 0) in pit_do_work.
212          */
213         smp_mb();
214         if (atomic_dec_if_positive(&ps->pending) > 0)
215                 kthread_queue_work(pit->worker, &pit->expired);
216 }
217 
218 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
219 {
220         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
221         struct hrtimer *timer;
222 
223         if (!kvm_vcpu_is_bsp(vcpu) || !pit)
224                 return;
225 
226         timer = &pit->pit_state.timer;
227         mutex_lock(&pit->pit_state.lock);
228         if (hrtimer_cancel(timer))
229                 hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
230         mutex_unlock(&pit->pit_state.lock);
231 }
232 
233 static void destroy_pit_timer(struct kvm_pit *pit)
234 {
235         hrtimer_cancel(&pit->pit_state.timer);
236         kthread_flush_work(&pit->expired);
237 }
238 
239 static void pit_do_work(struct kthread_work *work)
240 {
241         struct kvm_pit *pit = container_of(work, struct kvm_pit, expired);
242         struct kvm *kvm = pit->kvm;
243         struct kvm_vcpu *vcpu;
244         int i;
245         struct kvm_kpit_state *ps = &pit->pit_state;
246 
247         if (atomic_read(&ps->reinject) && !atomic_xchg(&ps->irq_ack, 0))
248                 return;
249 
250         kvm_set_irq(kvm, pit->irq_source_id, 0, 1, false);
251         kvm_set_irq(kvm, pit->irq_source_id, 0, 0, false);
252 
253         /*
254          * Provides NMI watchdog support via Virtual Wire mode.
255          * The route is: PIT -> LVT0 in NMI mode.
256          *
257          * Note: Our Virtual Wire implementation does not follow
258          * the MP specification.  We propagate a PIT interrupt to all
259          * VCPUs and only when LVT0 is in NMI mode.  The interrupt can
260          * also be simultaneously delivered through PIC and IOAPIC.
261          */
262         if (atomic_read(&kvm->arch.vapics_in_nmi_mode) > 0)
263                 kvm_for_each_vcpu(i, vcpu, kvm)
264                         kvm_apic_nmi_wd_deliver(vcpu);
265 }
266 
267 static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
268 {
269         struct kvm_kpit_state *ps = container_of(data, struct kvm_kpit_state, timer);
270         struct kvm_pit *pt = pit_state_to_pit(ps);
271 
272         if (atomic_read(&ps->reinject))
273                 atomic_inc(&ps->pending);
274 
275         kthread_queue_work(pt->worker, &pt->expired);
276 
277         if (ps->is_periodic) {
278                 hrtimer_add_expires_ns(&ps->timer, ps->period);
279                 return HRTIMER_RESTART;
280         } else
281                 return HRTIMER_NORESTART;
282 }
283 
284 static inline void kvm_pit_reset_reinject(struct kvm_pit *pit)
285 {
286         atomic_set(&pit->pit_state.pending, 0);
287         atomic_set(&pit->pit_state.irq_ack, 1);
288 }
289 
290 void kvm_pit_set_reinject(struct kvm_pit *pit, bool reinject)
291 {
292         struct kvm_kpit_state *ps = &pit->pit_state;
293         struct kvm *kvm = pit->kvm;
294 
295         if (atomic_read(&ps->reinject) == reinject)
296                 return;
297 
298         if (reinject) {
299                 /* The initial state is preserved while ps->reinject == 0. */
300                 kvm_pit_reset_reinject(pit);
301                 kvm_register_irq_ack_notifier(kvm, &ps->irq_ack_notifier);
302                 kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
303         } else {
304                 kvm_unregister_irq_ack_notifier(kvm, &ps->irq_ack_notifier);
305                 kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
306         }
307 
308         atomic_set(&ps->reinject, reinject);
309 }
310 
311 static void create_pit_timer(struct kvm_pit *pit, u32 val, int is_period)
312 {
313         struct kvm_kpit_state *ps = &pit->pit_state;
314         struct kvm *kvm = pit->kvm;
315         s64 interval;
316 
317         if (!ioapic_in_kernel(kvm) ||
318             ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)
319                 return;
320 
321         interval = mul_u64_u32_div(val, NSEC_PER_SEC, KVM_PIT_FREQ);
322 
323         pr_debug("create pit timer, interval is %llu nsec\n", interval);
324 
325         /* TODO The new value only affected after the retriggered */
326         hrtimer_cancel(&ps->timer);
327         kthread_flush_work(&pit->expired);
328         ps->period = interval;
329         ps->is_periodic = is_period;
330 
331         kvm_pit_reset_reinject(pit);
332 
333         /*
334          * Do not allow the guest to program periodic timers with small
335          * interval, since the hrtimers are not throttled by the host
336          * scheduler.
337          */
338         if (ps->is_periodic) {
339                 s64 min_period = min_timer_period_us * 1000LL;
340 
341                 if (ps->period < min_period) {
342                         pr_info_ratelimited(
343                             "kvm: requested %lld ns "
344                             "i8254 timer period limited to %lld ns\n",
345                             ps->period, min_period);
346                         ps->period = min_period;
347                 }
348         }
349 
350         hrtimer_start(&ps->timer, ktime_add_ns(ktime_get(), interval),
351                       HRTIMER_MODE_ABS);
352 }
353 
354 static void pit_load_count(struct kvm_pit *pit, int channel, u32 val)
355 {
356         struct kvm_kpit_state *ps = &pit->pit_state;
357 
358         pr_debug("load_count val is %d, channel is %d\n", val, channel);
359 
360         /*
361          * The largest possible initial count is 0; this is equivalent
362          * to 216 for binary counting and 104 for BCD counting.
363          */
364         if (val == 0)
365                 val = 0x10000;
366 
367         ps->channels[channel].count = val;
368 
369         if (channel != 0) {
370                 ps->channels[channel].count_load_time = ktime_get();
371                 return;
372         }
373 
374         /* Two types of timer
375          * mode 1 is one shot, mode 2 is period, otherwise del timer */
376         switch (ps->channels[0].mode) {
377         case 0:
378         case 1:
379         /* FIXME: enhance mode 4 precision */
380         case 4:
381                 create_pit_timer(pit, val, 0);
382                 break;
383         case 2:
384         case 3:
385                 create_pit_timer(pit, val, 1);
386                 break;
387         default:
388                 destroy_pit_timer(pit);
389         }
390 }
391 
392 void kvm_pit_load_count(struct kvm_pit *pit, int channel, u32 val,
393                 int hpet_legacy_start)
394 {
395         u8 saved_mode;
396 
397         WARN_ON_ONCE(!mutex_is_locked(&pit->pit_state.lock));
398 
399         if (hpet_legacy_start) {
400                 /* save existing mode for later reenablement */
401                 WARN_ON(channel != 0);
402                 saved_mode = pit->pit_state.channels[0].mode;
403                 pit->pit_state.channels[0].mode = 0xff; /* disable timer */
404                 pit_load_count(pit, channel, val);
405                 pit->pit_state.channels[0].mode = saved_mode;
406         } else {
407                 pit_load_count(pit, channel, val);
408         }
409 }
410 
411 static inline struct kvm_pit *dev_to_pit(struct kvm_io_device *dev)
412 {
413         return container_of(dev, struct kvm_pit, dev);
414 }
415 
416 static inline struct kvm_pit *speaker_to_pit(struct kvm_io_device *dev)
417 {
418         return container_of(dev, struct kvm_pit, speaker_dev);
419 }
420 
421 static inline int pit_in_range(gpa_t addr)
422 {
423         return ((addr >= KVM_PIT_BASE_ADDRESS) &&
424                 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
425 }
426 
427 static int pit_ioport_write(struct kvm_vcpu *vcpu,
428                                 struct kvm_io_device *this,
429                             gpa_t addr, int len, const void *data)
430 {
431         struct kvm_pit *pit = dev_to_pit(this);
432         struct kvm_kpit_state *pit_state = &pit->pit_state;
433         int channel, access;
434         struct kvm_kpit_channel_state *s;
435         u32 val = *(u32 *) data;
436         if (!pit_in_range(addr))
437                 return -EOPNOTSUPP;
438 
439         val  &= 0xff;
440         addr &= KVM_PIT_CHANNEL_MASK;
441 
442         mutex_lock(&pit_state->lock);
443 
444         if (val != 0)
445                 pr_debug("write addr is 0x%x, len is %d, val is 0x%x\n",
446                          (unsigned int)addr, len, val);
447 
448         if (addr == 3) {
449                 channel = val >> 6;
450                 if (channel == 3) {
451                         /* Read-Back Command. */
452                         for (channel = 0; channel < 3; channel++) {
453                                 s = &pit_state->channels[channel];
454                                 if (val & (2 << channel)) {
455                                         if (!(val & 0x20))
456                                                 pit_latch_count(pit, channel);
457                                         if (!(val & 0x10))
458                                                 pit_latch_status(pit, channel);
459                                 }
460                         }
461                 } else {
462                         /* Select Counter <channel>. */
463                         s = &pit_state->channels[channel];
464                         access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
465                         if (access == 0) {
466                                 pit_latch_count(pit, channel);
467                         } else {
468                                 s->rw_mode = access;
469                                 s->read_state = access;
470                                 s->write_state = access;
471                                 s->mode = (val >> 1) & 7;
472                                 if (s->mode > 5)
473                                         s->mode -= 4;
474                                 s->bcd = val & 1;
475                         }
476                 }
477         } else {
478                 /* Write Count. */
479                 s = &pit_state->channels[addr];
480                 switch (s->write_state) {
481                 default:
482                 case RW_STATE_LSB:
483                         pit_load_count(pit, addr, val);
484                         break;
485                 case RW_STATE_MSB:
486                         pit_load_count(pit, addr, val << 8);
487                         break;
488                 case RW_STATE_WORD0:
489                         s->write_latch = val;
490                         s->write_state = RW_STATE_WORD1;
491                         break;
492                 case RW_STATE_WORD1:
493                         pit_load_count(pit, addr, s->write_latch | (val << 8));
494                         s->write_state = RW_STATE_WORD0;
495                         break;
496                 }
497         }
498 
499         mutex_unlock(&pit_state->lock);
500         return 0;
501 }
502 
503 static int pit_ioport_read(struct kvm_vcpu *vcpu,
504                            struct kvm_io_device *this,
505                            gpa_t addr, int len, void *data)
506 {
507         struct kvm_pit *pit = dev_to_pit(this);
508         struct kvm_kpit_state *pit_state = &pit->pit_state;
509         int ret, count;
510         struct kvm_kpit_channel_state *s;
511         if (!pit_in_range(addr))
512                 return -EOPNOTSUPP;
513 
514         addr &= KVM_PIT_CHANNEL_MASK;
515         if (addr == 3)
516                 return 0;
517 
518         s = &pit_state->channels[addr];
519 
520         mutex_lock(&pit_state->lock);
521 
522         if (s->status_latched) {
523                 s->status_latched = 0;
524                 ret = s->status;
525         } else if (s->count_latched) {
526                 switch (s->count_latched) {
527                 default:
528                 case RW_STATE_LSB:
529                         ret = s->latched_count & 0xff;
530                         s->count_latched = 0;
531                         break;
532                 case RW_STATE_MSB:
533                         ret = s->latched_count >> 8;
534                         s->count_latched = 0;
535                         break;
536                 case RW_STATE_WORD0:
537                         ret = s->latched_count & 0xff;
538                         s->count_latched = RW_STATE_MSB;
539                         break;
540                 }
541         } else {
542                 switch (s->read_state) {
543                 default:
544                 case RW_STATE_LSB:
545                         count = pit_get_count(pit, addr);
546                         ret = count & 0xff;
547                         break;
548                 case RW_STATE_MSB:
549                         count = pit_get_count(pit, addr);
550                         ret = (count >> 8) & 0xff;
551                         break;
552                 case RW_STATE_WORD0:
553                         count = pit_get_count(pit, addr);
554                         ret = count & 0xff;
555                         s->read_state = RW_STATE_WORD1;
556                         break;
557                 case RW_STATE_WORD1:
558                         count = pit_get_count(pit, addr);
559                         ret = (count >> 8) & 0xff;
560                         s->read_state = RW_STATE_WORD0;
561                         break;
562                 }
563         }
564 
565         if (len > sizeof(ret))
566                 len = sizeof(ret);
567         memcpy(data, (char *)&ret, len);
568 
569         mutex_unlock(&pit_state->lock);
570         return 0;
571 }
572 
573 static int speaker_ioport_write(struct kvm_vcpu *vcpu,
574                                 struct kvm_io_device *this,
575                                 gpa_t addr, int len, const void *data)
576 {
577         struct kvm_pit *pit = speaker_to_pit(this);
578         struct kvm_kpit_state *pit_state = &pit->pit_state;
579         u32 val = *(u32 *) data;
580         if (addr != KVM_SPEAKER_BASE_ADDRESS)
581                 return -EOPNOTSUPP;
582 
583         mutex_lock(&pit_state->lock);
584         pit_state->speaker_data_on = (val >> 1) & 1;
585         pit_set_gate(pit, 2, val & 1);
586         mutex_unlock(&pit_state->lock);
587         return 0;
588 }
589 
590 static int speaker_ioport_read(struct kvm_vcpu *vcpu,
591                                    struct kvm_io_device *this,
592                                    gpa_t addr, int len, void *data)
593 {
594         struct kvm_pit *pit = speaker_to_pit(this);
595         struct kvm_kpit_state *pit_state = &pit->pit_state;
596         unsigned int refresh_clock;
597         int ret;
598         if (addr != KVM_SPEAKER_BASE_ADDRESS)
599                 return -EOPNOTSUPP;
600 
601         /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
602         refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
603 
604         mutex_lock(&pit_state->lock);
605         ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(pit, 2) |
606                 (pit_get_out(pit, 2) << 5) | (refresh_clock << 4));
607         if (len > sizeof(ret))
608                 len = sizeof(ret);
609         memcpy(data, (char *)&ret, len);
610         mutex_unlock(&pit_state->lock);
611         return 0;
612 }
613 
614 static void kvm_pit_reset(struct kvm_pit *pit)
615 {
616         int i;
617         struct kvm_kpit_channel_state *c;
618 
619         pit->pit_state.flags = 0;
620         for (i = 0; i < 3; i++) {
621                 c = &pit->pit_state.channels[i];
622                 c->mode = 0xff;
623                 c->gate = (i != 2);
624                 pit_load_count(pit, i, 0);
625         }
626 
627         kvm_pit_reset_reinject(pit);
628 }
629 
630 static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
631 {
632         struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
633 
634         if (!mask)
635                 kvm_pit_reset_reinject(pit);
636 }
637 
638 static const struct kvm_io_device_ops pit_dev_ops = {
639         .read     = pit_ioport_read,
640         .write    = pit_ioport_write,
641 };
642 
643 static const struct kvm_io_device_ops speaker_dev_ops = {
644         .read     = speaker_ioport_read,
645         .write    = speaker_ioport_write,
646 };
647 
648 struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
649 {
650         struct kvm_pit *pit;
651         struct kvm_kpit_state *pit_state;
652         struct pid *pid;
653         pid_t pid_nr;
654         int ret;
655 
656         pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
657         if (!pit)
658                 return NULL;
659 
660         pit->irq_source_id = kvm_request_irq_source_id(kvm);
661         if (pit->irq_source_id < 0)
662                 goto fail_request;
663 
664         mutex_init(&pit->pit_state.lock);
665 
666         pid = get_pid(task_tgid(current));
667         pid_nr = pid_vnr(pid);
668         put_pid(pid);
669 
670         pit->worker = kthread_create_worker(0, "kvm-pit/%d", pid_nr);
671         if (IS_ERR(pit->worker))
672                 goto fail_kthread;
673 
674         kthread_init_work(&pit->expired, pit_do_work);
675 
676         pit->kvm = kvm;
677 
678         pit_state = &pit->pit_state;
679         hrtimer_init(&pit_state->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
680         pit_state->timer.function = pit_timer_fn;
681 
682         pit_state->irq_ack_notifier.gsi = 0;
683         pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
684         pit->mask_notifier.func = pit_mask_notifer;
685 
686         kvm_pit_reset(pit);
687 
688         kvm_pit_set_reinject(pit, true);
689 
690         mutex_lock(&kvm->slots_lock);
691         kvm_iodevice_init(&pit->dev, &pit_dev_ops);
692         ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, KVM_PIT_BASE_ADDRESS,
693                                       KVM_PIT_MEM_LENGTH, &pit->dev);
694         if (ret < 0)
695                 goto fail_register_pit;
696 
697         if (flags & KVM_PIT_SPEAKER_DUMMY) {
698                 kvm_iodevice_init(&pit->speaker_dev, &speaker_dev_ops);
699                 ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS,
700                                               KVM_SPEAKER_BASE_ADDRESS, 4,
701                                               &pit->speaker_dev);
702                 if (ret < 0)
703                         goto fail_register_speaker;
704         }
705         mutex_unlock(&kvm->slots_lock);
706 
707         return pit;
708 
709 fail_register_speaker:
710         kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev);
711 fail_register_pit:
712         mutex_unlock(&kvm->slots_lock);
713         kvm_pit_set_reinject(pit, false);
714         kthread_destroy_worker(pit->worker);
715 fail_kthread:
716         kvm_free_irq_source_id(kvm, pit->irq_source_id);
717 fail_request:
718         kfree(pit);
719         return NULL;
720 }
721 
722 void kvm_free_pit(struct kvm *kvm)
723 {
724         struct kvm_pit *pit = kvm->arch.vpit;
725 
726         if (pit) {
727                 mutex_lock(&kvm->slots_lock);
728                 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev);
729                 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->speaker_dev);
730                 mutex_unlock(&kvm->slots_lock);
731                 kvm_pit_set_reinject(pit, false);
732                 hrtimer_cancel(&pit->pit_state.timer);
733                 kthread_destroy_worker(pit->worker);
734                 kvm_free_irq_source_id(kvm, pit->irq_source_id);
735                 kfree(pit);
736         }
737 }
738 

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