KVM: migrate PIT timer
[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  *
9  * Permission is hereby granted, free of charge, to any person obtaining a copy
10  * of this software and associated documentation files (the "Software"), to deal
11  * in the Software without restriction, including without limitation the rights
12  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
13  * copies of the Software, and to permit persons to whom the Software is
14  * furnished to do so, subject to the following conditions:
15  *
16  * The above copyright notice and this permission notice shall be included in
17  * all copies or substantial portions of the Software.
18  *
19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
22  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
25  * THE SOFTWARE.
26  *
27  * Authors:
28  *   Sheng Yang <sheng.yang@intel.com>
29  *   Based on QEMU and Xen.
30  */
31
32 #include <linux/kvm_host.h>
33
34 #include "irq.h"
35 #include "i8254.h"
36
37 #ifndef CONFIG_X86_64
38 #define mod_64(x, y) ((x) - (y) * div64_u64(x, y))
39 #else
40 #define mod_64(x, y) ((x) % (y))
41 #endif
42
43 #define RW_STATE_LSB 1
44 #define RW_STATE_MSB 2
45 #define RW_STATE_WORD0 3
46 #define RW_STATE_WORD1 4
47
48 /* Compute with 96 bit intermediate result: (a*b)/c */
49 static u64 muldiv64(u64 a, u32 b, u32 c)
50 {
51         union {
52                 u64 ll;
53                 struct {
54                         u32 low, high;
55                 } l;
56         } u, res;
57         u64 rl, rh;
58
59         u.ll = a;
60         rl = (u64)u.l.low * (u64)b;
61         rh = (u64)u.l.high * (u64)b;
62         rh += (rl >> 32);
63         res.l.high = div64_u64(rh, c);
64         res.l.low = div64_u64(((mod_64(rh, c) << 32) + (rl & 0xffffffff)), c);
65         return res.ll;
66 }
67
68 static void pit_set_gate(struct kvm *kvm, int channel, u32 val)
69 {
70         struct kvm_kpit_channel_state *c =
71                 &kvm->arch.vpit->pit_state.channels[channel];
72
73         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
74
75         switch (c->mode) {
76         default:
77         case 0:
78         case 4:
79                 /* XXX: just disable/enable counting */
80                 break;
81         case 1:
82         case 2:
83         case 3:
84         case 5:
85                 /* Restart counting on rising edge. */
86                 if (c->gate < val)
87                         c->count_load_time = ktime_get();
88                 break;
89         }
90
91         c->gate = val;
92 }
93
94 int pit_get_gate(struct kvm *kvm, int channel)
95 {
96         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
97
98         return kvm->arch.vpit->pit_state.channels[channel].gate;
99 }
100
101 static int pit_get_count(struct kvm *kvm, int channel)
102 {
103         struct kvm_kpit_channel_state *c =
104                 &kvm->arch.vpit->pit_state.channels[channel];
105         s64 d, t;
106         int counter;
107
108         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
109
110         t = ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));
111         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
112
113         switch (c->mode) {
114         case 0:
115         case 1:
116         case 4:
117         case 5:
118                 counter = (c->count - d) & 0xffff;
119                 break;
120         case 3:
121                 /* XXX: may be incorrect for odd counts */
122                 counter = c->count - (mod_64((2 * d), c->count));
123                 break;
124         default:
125                 counter = c->count - mod_64(d, c->count);
126                 break;
127         }
128         return counter;
129 }
130
131 static int pit_get_out(struct kvm *kvm, int channel)
132 {
133         struct kvm_kpit_channel_state *c =
134                 &kvm->arch.vpit->pit_state.channels[channel];
135         s64 d, t;
136         int out;
137
138         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
139
140         t = ktime_to_ns(ktime_sub(ktime_get(), c->count_load_time));
141         d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
142
143         switch (c->mode) {
144         default:
145         case 0:
146                 out = (d >= c->count);
147                 break;
148         case 1:
149                 out = (d < c->count);
150                 break;
151         case 2:
152                 out = ((mod_64(d, c->count) == 0) && (d != 0));
153                 break;
154         case 3:
155                 out = (mod_64(d, c->count) < ((c->count + 1) >> 1));
156                 break;
157         case 4:
158         case 5:
159                 out = (d == c->count);
160                 break;
161         }
162
163         return out;
164 }
165
166 static void pit_latch_count(struct kvm *kvm, int channel)
167 {
168         struct kvm_kpit_channel_state *c =
169                 &kvm->arch.vpit->pit_state.channels[channel];
170
171         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
172
173         if (!c->count_latched) {
174                 c->latched_count = pit_get_count(kvm, channel);
175                 c->count_latched = c->rw_mode;
176         }
177 }
178
179 static void pit_latch_status(struct kvm *kvm, int channel)
180 {
181         struct kvm_kpit_channel_state *c =
182                 &kvm->arch.vpit->pit_state.channels[channel];
183
184         WARN_ON(!mutex_is_locked(&kvm->arch.vpit->pit_state.lock));
185
186         if (!c->status_latched) {
187                 /* TODO: Return NULL COUNT (bit 6). */
188                 c->status = ((pit_get_out(kvm, channel) << 7) |
189                                 (c->rw_mode << 4) |
190                                 (c->mode << 1) |
191                                 c->bcd);
192                 c->status_latched = 1;
193         }
194 }
195
196 int __pit_timer_fn(struct kvm_kpit_state *ps)
197 {
198         struct kvm_vcpu *vcpu0 = ps->pit->kvm->vcpus[0];
199         struct kvm_kpit_timer *pt = &ps->pit_timer;
200
201         atomic_inc(&pt->pending);
202         smp_mb__after_atomic_inc();
203         if (vcpu0 && waitqueue_active(&vcpu0->wq)) {
204                 vcpu0->arch.mp_state = KVM_MP_STATE_RUNNABLE;
205                 wake_up_interruptible(&vcpu0->wq);
206         }
207
208         pt->timer.expires = ktime_add_ns(pt->timer.expires, pt->period);
209         pt->scheduled = ktime_to_ns(pt->timer.expires);
210
211         return (pt->period == 0 ? 0 : 1);
212 }
213
214 int pit_has_pending_timer(struct kvm_vcpu *vcpu)
215 {
216         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
217
218         if (pit && vcpu->vcpu_id == 0 && pit->pit_state.inject_pending)
219                 return atomic_read(&pit->pit_state.pit_timer.pending);
220
221         return 0;
222 }
223
224 static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
225 {
226         struct kvm_kpit_state *ps;
227         int restart_timer = 0;
228
229         ps = container_of(data, struct kvm_kpit_state, pit_timer.timer);
230
231         restart_timer = __pit_timer_fn(ps);
232
233         if (restart_timer)
234                 return HRTIMER_RESTART;
235         else
236                 return HRTIMER_NORESTART;
237 }
238
239 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
240 {
241         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
242         struct hrtimer *timer;
243
244         if (vcpu->vcpu_id != 0 || !pit)
245                 return;
246
247         timer = &pit->pit_state.pit_timer.timer;
248         if (hrtimer_cancel(timer))
249                 hrtimer_start(timer, timer->expires, HRTIMER_MODE_ABS);
250 }
251
252 static void destroy_pit_timer(struct kvm_kpit_timer *pt)
253 {
254         pr_debug("pit: execute del timer!\n");
255         hrtimer_cancel(&pt->timer);
256 }
257
258 static void create_pit_timer(struct kvm_kpit_timer *pt, u32 val, int is_period)
259 {
260         s64 interval;
261
262         interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
263
264         pr_debug("pit: create pit timer, interval is %llu nsec\n", interval);
265
266         /* TODO The new value only affected after the retriggered */
267         hrtimer_cancel(&pt->timer);
268         pt->period = (is_period == 0) ? 0 : interval;
269         pt->timer.function = pit_timer_fn;
270         atomic_set(&pt->pending, 0);
271
272         hrtimer_start(&pt->timer, ktime_add_ns(ktime_get(), interval),
273                       HRTIMER_MODE_ABS);
274 }
275
276 static void pit_load_count(struct kvm *kvm, int channel, u32 val)
277 {
278         struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
279
280         WARN_ON(!mutex_is_locked(&ps->lock));
281
282         pr_debug("pit: load_count val is %d, channel is %d\n", val, channel);
283
284         /*
285          * Though spec said the state of 8254 is undefined after power-up,
286          * seems some tricky OS like Windows XP depends on IRQ0 interrupt
287          * when booting up.
288          * So here setting initialize rate for it, and not a specific number
289          */
290         if (val == 0)
291                 val = 0x10000;
292
293         ps->channels[channel].count_load_time = ktime_get();
294         ps->channels[channel].count = val;
295
296         if (channel != 0)
297                 return;
298
299         /* Two types of timer
300          * mode 1 is one shot, mode 2 is period, otherwise del timer */
301         switch (ps->channels[0].mode) {
302         case 1:
303         /* FIXME: enhance mode 4 precision */
304         case 4:
305                 create_pit_timer(&ps->pit_timer, val, 0);
306                 break;
307         case 2:
308                 create_pit_timer(&ps->pit_timer, val, 1);
309                 break;
310         default:
311                 destroy_pit_timer(&ps->pit_timer);
312         }
313 }
314
315 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val)
316 {
317         mutex_lock(&kvm->arch.vpit->pit_state.lock);
318         pit_load_count(kvm, channel, val);
319         mutex_unlock(&kvm->arch.vpit->pit_state.lock);
320 }
321
322 static void pit_ioport_write(struct kvm_io_device *this,
323                              gpa_t addr, int len, const void *data)
324 {
325         struct kvm_pit *pit = (struct kvm_pit *)this->private;
326         struct kvm_kpit_state *pit_state = &pit->pit_state;
327         struct kvm *kvm = pit->kvm;
328         int channel, access;
329         struct kvm_kpit_channel_state *s;
330         u32 val = *(u32 *) data;
331
332         val  &= 0xff;
333         addr &= KVM_PIT_CHANNEL_MASK;
334
335         mutex_lock(&pit_state->lock);
336
337         if (val != 0)
338                 pr_debug("pit: write addr is 0x%x, len is %d, val is 0x%x\n",
339                           (unsigned int)addr, len, val);
340
341         if (addr == 3) {
342                 channel = val >> 6;
343                 if (channel == 3) {
344                         /* Read-Back Command. */
345                         for (channel = 0; channel < 3; channel++) {
346                                 s = &pit_state->channels[channel];
347                                 if (val & (2 << channel)) {
348                                         if (!(val & 0x20))
349                                                 pit_latch_count(kvm, channel);
350                                         if (!(val & 0x10))
351                                                 pit_latch_status(kvm, channel);
352                                 }
353                         }
354                 } else {
355                         /* Select Counter <channel>. */
356                         s = &pit_state->channels[channel];
357                         access = (val >> 4) & KVM_PIT_CHANNEL_MASK;
358                         if (access == 0) {
359                                 pit_latch_count(kvm, channel);
360                         } else {
361                                 s->rw_mode = access;
362                                 s->read_state = access;
363                                 s->write_state = access;
364                                 s->mode = (val >> 1) & 7;
365                                 if (s->mode > 5)
366                                         s->mode -= 4;
367                                 s->bcd = val & 1;
368                         }
369                 }
370         } else {
371                 /* Write Count. */
372                 s = &pit_state->channels[addr];
373                 switch (s->write_state) {
374                 default:
375                 case RW_STATE_LSB:
376                         pit_load_count(kvm, addr, val);
377                         break;
378                 case RW_STATE_MSB:
379                         pit_load_count(kvm, addr, val << 8);
380                         break;
381                 case RW_STATE_WORD0:
382                         s->write_latch = val;
383                         s->write_state = RW_STATE_WORD1;
384                         break;
385                 case RW_STATE_WORD1:
386                         pit_load_count(kvm, addr, s->write_latch | (val << 8));
387                         s->write_state = RW_STATE_WORD0;
388                         break;
389                 }
390         }
391
392         mutex_unlock(&pit_state->lock);
393 }
394
395 static void pit_ioport_read(struct kvm_io_device *this,
396                             gpa_t addr, int len, void *data)
397 {
398         struct kvm_pit *pit = (struct kvm_pit *)this->private;
399         struct kvm_kpit_state *pit_state = &pit->pit_state;
400         struct kvm *kvm = pit->kvm;
401         int ret, count;
402         struct kvm_kpit_channel_state *s;
403
404         addr &= KVM_PIT_CHANNEL_MASK;
405         s = &pit_state->channels[addr];
406
407         mutex_lock(&pit_state->lock);
408
409         if (s->status_latched) {
410                 s->status_latched = 0;
411                 ret = s->status;
412         } else if (s->count_latched) {
413                 switch (s->count_latched) {
414                 default:
415                 case RW_STATE_LSB:
416                         ret = s->latched_count & 0xff;
417                         s->count_latched = 0;
418                         break;
419                 case RW_STATE_MSB:
420                         ret = s->latched_count >> 8;
421                         s->count_latched = 0;
422                         break;
423                 case RW_STATE_WORD0:
424                         ret = s->latched_count & 0xff;
425                         s->count_latched = RW_STATE_MSB;
426                         break;
427                 }
428         } else {
429                 switch (s->read_state) {
430                 default:
431                 case RW_STATE_LSB:
432                         count = pit_get_count(kvm, addr);
433                         ret = count & 0xff;
434                         break;
435                 case RW_STATE_MSB:
436                         count = pit_get_count(kvm, addr);
437                         ret = (count >> 8) & 0xff;
438                         break;
439                 case RW_STATE_WORD0:
440                         count = pit_get_count(kvm, addr);
441                         ret = count & 0xff;
442                         s->read_state = RW_STATE_WORD1;
443                         break;
444                 case RW_STATE_WORD1:
445                         count = pit_get_count(kvm, addr);
446                         ret = (count >> 8) & 0xff;
447                         s->read_state = RW_STATE_WORD0;
448                         break;
449                 }
450         }
451
452         if (len > sizeof(ret))
453                 len = sizeof(ret);
454         memcpy(data, (char *)&ret, len);
455
456         mutex_unlock(&pit_state->lock);
457 }
458
459 static int pit_in_range(struct kvm_io_device *this, gpa_t addr)
460 {
461         return ((addr >= KVM_PIT_BASE_ADDRESS) &&
462                 (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
463 }
464
465 static void speaker_ioport_write(struct kvm_io_device *this,
466                                  gpa_t addr, int len, const void *data)
467 {
468         struct kvm_pit *pit = (struct kvm_pit *)this->private;
469         struct kvm_kpit_state *pit_state = &pit->pit_state;
470         struct kvm *kvm = pit->kvm;
471         u32 val = *(u32 *) data;
472
473         mutex_lock(&pit_state->lock);
474         pit_state->speaker_data_on = (val >> 1) & 1;
475         pit_set_gate(kvm, 2, val & 1);
476         mutex_unlock(&pit_state->lock);
477 }
478
479 static void speaker_ioport_read(struct kvm_io_device *this,
480                                 gpa_t addr, int len, void *data)
481 {
482         struct kvm_pit *pit = (struct kvm_pit *)this->private;
483         struct kvm_kpit_state *pit_state = &pit->pit_state;
484         struct kvm *kvm = pit->kvm;
485         unsigned int refresh_clock;
486         int ret;
487
488         /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
489         refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
490
491         mutex_lock(&pit_state->lock);
492         ret = ((pit_state->speaker_data_on << 1) | pit_get_gate(kvm, 2) |
493                 (pit_get_out(kvm, 2) << 5) | (refresh_clock << 4));
494         if (len > sizeof(ret))
495                 len = sizeof(ret);
496         memcpy(data, (char *)&ret, len);
497         mutex_unlock(&pit_state->lock);
498 }
499
500 static int speaker_in_range(struct kvm_io_device *this, gpa_t addr)
501 {
502         return (addr == KVM_SPEAKER_BASE_ADDRESS);
503 }
504
505 void kvm_pit_reset(struct kvm_pit *pit)
506 {
507         int i;
508         struct kvm_kpit_channel_state *c;
509
510         mutex_lock(&pit->pit_state.lock);
511         for (i = 0; i < 3; i++) {
512                 c = &pit->pit_state.channels[i];
513                 c->mode = 0xff;
514                 c->gate = (i != 2);
515                 pit_load_count(pit->kvm, i, 0);
516         }
517         mutex_unlock(&pit->pit_state.lock);
518
519         atomic_set(&pit->pit_state.pit_timer.pending, 0);
520         pit->pit_state.inject_pending = 1;
521 }
522
523 struct kvm_pit *kvm_create_pit(struct kvm *kvm)
524 {
525         struct kvm_pit *pit;
526         struct kvm_kpit_state *pit_state;
527
528         pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
529         if (!pit)
530                 return NULL;
531
532         mutex_init(&pit->pit_state.lock);
533         mutex_lock(&pit->pit_state.lock);
534
535         /* Initialize PIO device */
536         pit->dev.read = pit_ioport_read;
537         pit->dev.write = pit_ioport_write;
538         pit->dev.in_range = pit_in_range;
539         pit->dev.private = pit;
540         kvm_io_bus_register_dev(&kvm->pio_bus, &pit->dev);
541
542         pit->speaker_dev.read = speaker_ioport_read;
543         pit->speaker_dev.write = speaker_ioport_write;
544         pit->speaker_dev.in_range = speaker_in_range;
545         pit->speaker_dev.private = pit;
546         kvm_io_bus_register_dev(&kvm->pio_bus, &pit->speaker_dev);
547
548         kvm->arch.vpit = pit;
549         pit->kvm = kvm;
550
551         pit_state = &pit->pit_state;
552         pit_state->pit = pit;
553         hrtimer_init(&pit_state->pit_timer.timer,
554                      CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
555         mutex_unlock(&pit->pit_state.lock);
556
557         kvm_pit_reset(pit);
558
559         return pit;
560 }
561
562 void kvm_free_pit(struct kvm *kvm)
563 {
564         struct hrtimer *timer;
565
566         if (kvm->arch.vpit) {
567                 mutex_lock(&kvm->arch.vpit->pit_state.lock);
568                 timer = &kvm->arch.vpit->pit_state.pit_timer.timer;
569                 hrtimer_cancel(timer);
570                 mutex_unlock(&kvm->arch.vpit->pit_state.lock);
571                 kfree(kvm->arch.vpit);
572         }
573 }
574
575 void __inject_pit_timer_intr(struct kvm *kvm)
576 {
577         mutex_lock(&kvm->lock);
578         kvm_ioapic_set_irq(kvm->arch.vioapic, 0, 1);
579         kvm_ioapic_set_irq(kvm->arch.vioapic, 0, 0);
580         kvm_pic_set_irq(pic_irqchip(kvm), 0, 1);
581         kvm_pic_set_irq(pic_irqchip(kvm), 0, 0);
582         mutex_unlock(&kvm->lock);
583 }
584
585 void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu)
586 {
587         struct kvm_pit *pit = vcpu->kvm->arch.vpit;
588         struct kvm *kvm = vcpu->kvm;
589         struct kvm_kpit_state *ps;
590
591         if (vcpu && pit) {
592                 ps = &pit->pit_state;
593
594                 /* Try to inject pending interrupts when:
595                  * 1. Pending exists
596                  * 2. Last interrupt was accepted or waited for too long time*/
597                 if (atomic_read(&ps->pit_timer.pending) &&
598                     (ps->inject_pending ||
599                     (jiffies - ps->last_injected_time
600                                 >= KVM_MAX_PIT_INTR_INTERVAL))) {
601                         ps->inject_pending = 0;
602                         __inject_pit_timer_intr(kvm);
603                         ps->last_injected_time = jiffies;
604                 }
605         }
606 }
607
608 void kvm_pit_timer_intr_post(struct kvm_vcpu *vcpu, int vec)
609 {
610         struct kvm_arch *arch = &vcpu->kvm->arch;
611         struct kvm_kpit_state *ps;
612
613         if (vcpu && arch->vpit) {
614                 ps = &arch->vpit->pit_state;
615                 if (atomic_read(&ps->pit_timer.pending) &&
616                 (((arch->vpic->pics[0].imr & 1) == 0 &&
617                   arch->vpic->pics[0].irq_base == vec) ||
618                   (arch->vioapic->redirtbl[0].fields.vector == vec &&
619                   arch->vioapic->redirtbl[0].fields.mask != 1))) {
620                         ps->inject_pending = 1;
621                         atomic_dec(&ps->pit_timer.pending);
622                         ps->channels[0].count_load_time = ktime_get();
623                 }
624         }
625 }