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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 "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 */
 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->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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 
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 */
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 
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 

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