2 * 8253/8254 interval timer emulation
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
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:
16 * The above copyright notice and this permission notice shall be included in
17 * all copies or substantial portions of the Software.
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
28 * Sheng Yang <sheng.yang@intel.com>
29 * Based on QEMU and Xen.
32 #include <linux/kvm_host.h>
38 #define mod_64(x, y) ((x) - (y) * div64_u64(x, y))
40 #define mod_64(x, y) ((x) % (y))
43 #define RW_STATE_LSB 1
44 #define RW_STATE_MSB 2
45 #define RW_STATE_WORD0 3
46 #define RW_STATE_WORD1 4
48 /* Compute with 96 bit intermediate result: (a*b)/c */
49 static u64
muldiv64(u64 a
, u32 b
, u32 c
)
60 rl
= (u64
)u
.l
.low
* (u64
)b
;
61 rh
= (u64
)u
.l
.high
* (u64
)b
;
63 res
.l
.high
= div64_u64(rh
, c
);
64 res
.l
.low
= div64_u64(((mod_64(rh
, c
) << 32) + (rl
& 0xffffffff)), c
);
68 static void pit_set_gate(struct kvm
*kvm
, int channel
, u32 val
)
70 struct kvm_kpit_channel_state
*c
=
71 &kvm
->arch
.vpit
->pit_state
.channels
[channel
];
73 WARN_ON(!mutex_is_locked(&kvm
->arch
.vpit
->pit_state
.lock
));
79 /* XXX: just disable/enable counting */
85 /* Restart counting on rising edge. */
87 c
->count_load_time
= ktime_get();
94 static int pit_get_gate(struct kvm
*kvm
, int channel
)
96 WARN_ON(!mutex_is_locked(&kvm
->arch
.vpit
->pit_state
.lock
));
98 return kvm
->arch
.vpit
->pit_state
.channels
[channel
].gate
;
101 static s64
__kpit_elapsed(struct kvm
*kvm
)
105 struct kvm_kpit_state
*ps
= &kvm
->arch
.vpit
->pit_state
;
107 remaining
= hrtimer_expires_remaining(&ps
->pit_timer
.timer
);
108 if (ktime_to_ns(remaining
) < 0)
109 remaining
= ktime_set(0, 0);
111 elapsed
= ps
->pit_timer
.period
;
112 if (ktime_to_ns(remaining
) <= ps
->pit_timer
.period
)
113 elapsed
= ps
->pit_timer
.period
- ktime_to_ns(remaining
);
118 static s64
kpit_elapsed(struct kvm
*kvm
, struct kvm_kpit_channel_state
*c
,
122 return __kpit_elapsed(kvm
);
124 return ktime_to_ns(ktime_sub(ktime_get(), c
->count_load_time
));
127 static int pit_get_count(struct kvm
*kvm
, int channel
)
129 struct kvm_kpit_channel_state
*c
=
130 &kvm
->arch
.vpit
->pit_state
.channels
[channel
];
134 WARN_ON(!mutex_is_locked(&kvm
->arch
.vpit
->pit_state
.lock
));
136 t
= kpit_elapsed(kvm
, c
, channel
);
137 d
= muldiv64(t
, KVM_PIT_FREQ
, NSEC_PER_SEC
);
144 counter
= (c
->count
- d
) & 0xffff;
147 /* XXX: may be incorrect for odd counts */
148 counter
= c
->count
- (mod_64((2 * d
), c
->count
));
151 counter
= c
->count
- mod_64(d
, c
->count
);
157 static int pit_get_out(struct kvm
*kvm
, int channel
)
159 struct kvm_kpit_channel_state
*c
=
160 &kvm
->arch
.vpit
->pit_state
.channels
[channel
];
164 WARN_ON(!mutex_is_locked(&kvm
->arch
.vpit
->pit_state
.lock
));
166 t
= kpit_elapsed(kvm
, c
, channel
);
167 d
= muldiv64(t
, KVM_PIT_FREQ
, NSEC_PER_SEC
);
172 out
= (d
>= c
->count
);
175 out
= (d
< c
->count
);
178 out
= ((mod_64(d
, c
->count
) == 0) && (d
!= 0));
181 out
= (mod_64(d
, c
->count
) < ((c
->count
+ 1) >> 1));
185 out
= (d
== c
->count
);
192 static void pit_latch_count(struct kvm
*kvm
, int channel
)
194 struct kvm_kpit_channel_state
*c
=
195 &kvm
->arch
.vpit
->pit_state
.channels
[channel
];
197 WARN_ON(!mutex_is_locked(&kvm
->arch
.vpit
->pit_state
.lock
));
199 if (!c
->count_latched
) {
200 c
->latched_count
= pit_get_count(kvm
, channel
);
201 c
->count_latched
= c
->rw_mode
;
205 static void pit_latch_status(struct kvm
*kvm
, int channel
)
207 struct kvm_kpit_channel_state
*c
=
208 &kvm
->arch
.vpit
->pit_state
.channels
[channel
];
210 WARN_ON(!mutex_is_locked(&kvm
->arch
.vpit
->pit_state
.lock
));
212 if (!c
->status_latched
) {
213 /* TODO: Return NULL COUNT (bit 6). */
214 c
->status
= ((pit_get_out(kvm
, channel
) << 7) |
218 c
->status_latched
= 1;
222 static int __pit_timer_fn(struct kvm_kpit_state
*ps
)
224 struct kvm_vcpu
*vcpu0
= ps
->pit
->kvm
->vcpus
[0];
225 struct kvm_kpit_timer
*pt
= &ps
->pit_timer
;
227 if (!atomic_inc_and_test(&pt
->pending
))
228 set_bit(KVM_REQ_PENDING_TIMER
, &vcpu0
->requests
);
231 atomic_set(&pt
->pending
, 1);
233 if (vcpu0
&& waitqueue_active(&vcpu0
->wq
))
234 wake_up_interruptible(&vcpu0
->wq
);
236 hrtimer_add_expires_ns(&pt
->timer
, pt
->period
);
238 return (pt
->period
== 0 ? 0 : 1);
241 int pit_has_pending_timer(struct kvm_vcpu
*vcpu
)
243 struct kvm_pit
*pit
= vcpu
->kvm
->arch
.vpit
;
245 if (pit
&& vcpu
->vcpu_id
== 0 && pit
->pit_state
.irq_ack
)
246 return atomic_read(&pit
->pit_state
.pit_timer
.pending
);
250 static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier
*kian
)
252 struct kvm_kpit_state
*ps
= container_of(kian
, struct kvm_kpit_state
,
254 spin_lock(&ps
->inject_lock
);
255 if (atomic_dec_return(&ps
->pit_timer
.pending
) < 0)
256 atomic_inc(&ps
->pit_timer
.pending
);
258 spin_unlock(&ps
->inject_lock
);
261 static enum hrtimer_restart
pit_timer_fn(struct hrtimer
*data
)
263 struct kvm_kpit_state
*ps
;
264 int restart_timer
= 0;
266 ps
= container_of(data
, struct kvm_kpit_state
, pit_timer
.timer
);
268 restart_timer
= __pit_timer_fn(ps
);
271 return HRTIMER_RESTART
;
273 return HRTIMER_NORESTART
;
276 void __kvm_migrate_pit_timer(struct kvm_vcpu
*vcpu
)
278 struct kvm_pit
*pit
= vcpu
->kvm
->arch
.vpit
;
279 struct hrtimer
*timer
;
281 if (vcpu
->vcpu_id
!= 0 || !pit
)
284 timer
= &pit
->pit_state
.pit_timer
.timer
;
285 if (hrtimer_cancel(timer
))
286 hrtimer_start_expires(timer
, HRTIMER_MODE_ABS
);
289 static void destroy_pit_timer(struct kvm_kpit_timer
*pt
)
291 pr_debug("pit: execute del timer!\n");
292 hrtimer_cancel(&pt
->timer
);
295 static void create_pit_timer(struct kvm_kpit_state
*ps
, u32 val
, int is_period
)
297 struct kvm_kpit_timer
*pt
= &ps
->pit_timer
;
300 interval
= muldiv64(val
, NSEC_PER_SEC
, KVM_PIT_FREQ
);
302 pr_debug("pit: create pit timer, interval is %llu nsec\n", interval
);
304 /* TODO The new value only affected after the retriggered */
305 hrtimer_cancel(&pt
->timer
);
306 pt
->period
= (is_period
== 0) ? 0 : interval
;
307 pt
->timer
.function
= pit_timer_fn
;
308 atomic_set(&pt
->pending
, 0);
311 hrtimer_start(&pt
->timer
, ktime_add_ns(ktime_get(), interval
),
315 static void pit_load_count(struct kvm
*kvm
, int channel
, u32 val
)
317 struct kvm_kpit_state
*ps
= &kvm
->arch
.vpit
->pit_state
;
319 WARN_ON(!mutex_is_locked(&ps
->lock
));
321 pr_debug("pit: load_count val is %d, channel is %d\n", val
, channel
);
324 * Though spec said the state of 8254 is undefined after power-up,
325 * seems some tricky OS like Windows XP depends on IRQ0 interrupt
327 * So here setting initialize rate for it, and not a specific number
332 ps
->channels
[channel
].count
= val
;
335 ps
->channels
[channel
].count_load_time
= ktime_get();
339 /* Two types of timer
340 * mode 1 is one shot, mode 2 is period, otherwise del timer */
341 switch (ps
->channels
[0].mode
) {
343 /* FIXME: enhance mode 4 precision */
345 create_pit_timer(ps
, val
, 0);
349 create_pit_timer(ps
, val
, 1);
352 destroy_pit_timer(&ps
->pit_timer
);
356 void kvm_pit_load_count(struct kvm
*kvm
, int channel
, u32 val
)
358 mutex_lock(&kvm
->arch
.vpit
->pit_state
.lock
);
359 pit_load_count(kvm
, channel
, val
);
360 mutex_unlock(&kvm
->arch
.vpit
->pit_state
.lock
);
363 static void pit_ioport_write(struct kvm_io_device
*this,
364 gpa_t addr
, int len
, const void *data
)
366 struct kvm_pit
*pit
= (struct kvm_pit
*)this->private;
367 struct kvm_kpit_state
*pit_state
= &pit
->pit_state
;
368 struct kvm
*kvm
= pit
->kvm
;
370 struct kvm_kpit_channel_state
*s
;
371 u32 val
= *(u32
*) data
;
374 addr
&= KVM_PIT_CHANNEL_MASK
;
376 mutex_lock(&pit_state
->lock
);
379 pr_debug("pit: write addr is 0x%x, len is %d, val is 0x%x\n",
380 (unsigned int)addr
, len
, val
);
385 /* Read-Back Command. */
386 for (channel
= 0; channel
< 3; channel
++) {
387 s
= &pit_state
->channels
[channel
];
388 if (val
& (2 << channel
)) {
390 pit_latch_count(kvm
, channel
);
392 pit_latch_status(kvm
, channel
);
396 /* Select Counter <channel>. */
397 s
= &pit_state
->channels
[channel
];
398 access
= (val
>> 4) & KVM_PIT_CHANNEL_MASK
;
400 pit_latch_count(kvm
, channel
);
403 s
->read_state
= access
;
404 s
->write_state
= access
;
405 s
->mode
= (val
>> 1) & 7;
413 s
= &pit_state
->channels
[addr
];
414 switch (s
->write_state
) {
417 pit_load_count(kvm
, addr
, val
);
420 pit_load_count(kvm
, addr
, val
<< 8);
423 s
->write_latch
= val
;
424 s
->write_state
= RW_STATE_WORD1
;
427 pit_load_count(kvm
, addr
, s
->write_latch
| (val
<< 8));
428 s
->write_state
= RW_STATE_WORD0
;
433 mutex_unlock(&pit_state
->lock
);
436 static void pit_ioport_read(struct kvm_io_device
*this,
437 gpa_t addr
, int len
, void *data
)
439 struct kvm_pit
*pit
= (struct kvm_pit
*)this->private;
440 struct kvm_kpit_state
*pit_state
= &pit
->pit_state
;
441 struct kvm
*kvm
= pit
->kvm
;
443 struct kvm_kpit_channel_state
*s
;
445 addr
&= KVM_PIT_CHANNEL_MASK
;
446 s
= &pit_state
->channels
[addr
];
448 mutex_lock(&pit_state
->lock
);
450 if (s
->status_latched
) {
451 s
->status_latched
= 0;
453 } else if (s
->count_latched
) {
454 switch (s
->count_latched
) {
457 ret
= s
->latched_count
& 0xff;
458 s
->count_latched
= 0;
461 ret
= s
->latched_count
>> 8;
462 s
->count_latched
= 0;
465 ret
= s
->latched_count
& 0xff;
466 s
->count_latched
= RW_STATE_MSB
;
470 switch (s
->read_state
) {
473 count
= pit_get_count(kvm
, addr
);
477 count
= pit_get_count(kvm
, addr
);
478 ret
= (count
>> 8) & 0xff;
481 count
= pit_get_count(kvm
, addr
);
483 s
->read_state
= RW_STATE_WORD1
;
486 count
= pit_get_count(kvm
, addr
);
487 ret
= (count
>> 8) & 0xff;
488 s
->read_state
= RW_STATE_WORD0
;
493 if (len
> sizeof(ret
))
495 memcpy(data
, (char *)&ret
, len
);
497 mutex_unlock(&pit_state
->lock
);
500 static int pit_in_range(struct kvm_io_device
*this, gpa_t addr
,
501 int len
, int is_write
)
503 return ((addr
>= KVM_PIT_BASE_ADDRESS
) &&
504 (addr
< KVM_PIT_BASE_ADDRESS
+ KVM_PIT_MEM_LENGTH
));
507 static void speaker_ioport_write(struct kvm_io_device
*this,
508 gpa_t addr
, int len
, const void *data
)
510 struct kvm_pit
*pit
= (struct kvm_pit
*)this->private;
511 struct kvm_kpit_state
*pit_state
= &pit
->pit_state
;
512 struct kvm
*kvm
= pit
->kvm
;
513 u32 val
= *(u32
*) data
;
515 mutex_lock(&pit_state
->lock
);
516 pit_state
->speaker_data_on
= (val
>> 1) & 1;
517 pit_set_gate(kvm
, 2, val
& 1);
518 mutex_unlock(&pit_state
->lock
);
521 static void speaker_ioport_read(struct kvm_io_device
*this,
522 gpa_t addr
, int len
, void *data
)
524 struct kvm_pit
*pit
= (struct kvm_pit
*)this->private;
525 struct kvm_kpit_state
*pit_state
= &pit
->pit_state
;
526 struct kvm
*kvm
= pit
->kvm
;
527 unsigned int refresh_clock
;
530 /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
531 refresh_clock
= ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
533 mutex_lock(&pit_state
->lock
);
534 ret
= ((pit_state
->speaker_data_on
<< 1) | pit_get_gate(kvm
, 2) |
535 (pit_get_out(kvm
, 2) << 5) | (refresh_clock
<< 4));
536 if (len
> sizeof(ret
))
538 memcpy(data
, (char *)&ret
, len
);
539 mutex_unlock(&pit_state
->lock
);
542 static int speaker_in_range(struct kvm_io_device
*this, gpa_t addr
,
543 int len
, int is_write
)
545 return (addr
== KVM_SPEAKER_BASE_ADDRESS
);
548 void kvm_pit_reset(struct kvm_pit
*pit
)
551 struct kvm_kpit_channel_state
*c
;
553 mutex_lock(&pit
->pit_state
.lock
);
554 for (i
= 0; i
< 3; i
++) {
555 c
= &pit
->pit_state
.channels
[i
];
558 pit_load_count(pit
->kvm
, i
, 0);
560 mutex_unlock(&pit
->pit_state
.lock
);
562 atomic_set(&pit
->pit_state
.pit_timer
.pending
, 0);
563 pit
->pit_state
.irq_ack
= 1;
566 static void pit_mask_notifer(struct kvm_irq_mask_notifier
*kimn
, bool mask
)
568 struct kvm_pit
*pit
= container_of(kimn
, struct kvm_pit
, mask_notifier
);
571 atomic_set(&pit
->pit_state
.pit_timer
.pending
, 0);
572 pit
->pit_state
.irq_ack
= 1;
576 struct kvm_pit
*kvm_create_pit(struct kvm
*kvm
)
579 struct kvm_kpit_state
*pit_state
;
581 pit
= kzalloc(sizeof(struct kvm_pit
), GFP_KERNEL
);
585 pit
->irq_source_id
= kvm_request_irq_source_id(kvm
);
586 if (pit
->irq_source_id
< 0) {
591 mutex_init(&pit
->pit_state
.lock
);
592 mutex_lock(&pit
->pit_state
.lock
);
593 spin_lock_init(&pit
->pit_state
.inject_lock
);
595 /* Initialize PIO device */
596 pit
->dev
.read
= pit_ioport_read
;
597 pit
->dev
.write
= pit_ioport_write
;
598 pit
->dev
.in_range
= pit_in_range
;
599 pit
->dev
.private = pit
;
600 kvm_io_bus_register_dev(&kvm
->pio_bus
, &pit
->dev
);
602 pit
->speaker_dev
.read
= speaker_ioport_read
;
603 pit
->speaker_dev
.write
= speaker_ioport_write
;
604 pit
->speaker_dev
.in_range
= speaker_in_range
;
605 pit
->speaker_dev
.private = pit
;
606 kvm_io_bus_register_dev(&kvm
->pio_bus
, &pit
->speaker_dev
);
608 kvm
->arch
.vpit
= pit
;
611 pit_state
= &pit
->pit_state
;
612 pit_state
->pit
= pit
;
613 hrtimer_init(&pit_state
->pit_timer
.timer
,
614 CLOCK_MONOTONIC
, HRTIMER_MODE_ABS
);
615 pit_state
->irq_ack_notifier
.gsi
= 0;
616 pit_state
->irq_ack_notifier
.irq_acked
= kvm_pit_ack_irq
;
617 kvm_register_irq_ack_notifier(kvm
, &pit_state
->irq_ack_notifier
);
618 pit_state
->pit_timer
.reinject
= true;
619 mutex_unlock(&pit
->pit_state
.lock
);
623 pit
->mask_notifier
.func
= pit_mask_notifer
;
624 kvm_register_irq_mask_notifier(kvm
, 0, &pit
->mask_notifier
);
629 void kvm_free_pit(struct kvm
*kvm
)
631 struct hrtimer
*timer
;
633 if (kvm
->arch
.vpit
) {
634 kvm_unregister_irq_mask_notifier(kvm
, 0,
635 &kvm
->arch
.vpit
->mask_notifier
);
636 mutex_lock(&kvm
->arch
.vpit
->pit_state
.lock
);
637 timer
= &kvm
->arch
.vpit
->pit_state
.pit_timer
.timer
;
638 hrtimer_cancel(timer
);
639 kvm_free_irq_source_id(kvm
, kvm
->arch
.vpit
->irq_source_id
);
640 mutex_unlock(&kvm
->arch
.vpit
->pit_state
.lock
);
641 kfree(kvm
->arch
.vpit
);
645 static void __inject_pit_timer_intr(struct kvm
*kvm
)
647 struct kvm_vcpu
*vcpu
;
650 mutex_lock(&kvm
->lock
);
651 kvm_set_irq(kvm
, kvm
->arch
.vpit
->irq_source_id
, 0, 1);
652 kvm_set_irq(kvm
, kvm
->arch
.vpit
->irq_source_id
, 0, 0);
653 mutex_unlock(&kvm
->lock
);
656 * Provides NMI watchdog support via Virtual Wire mode.
657 * The route is: PIT -> PIC -> LVT0 in NMI mode.
659 * Note: Our Virtual Wire implementation is simplified, only
660 * propagating PIT interrupts to all VCPUs when they have set
661 * LVT0 to NMI delivery. Other PIC interrupts are just sent to
662 * VCPU0, and only if its LVT0 is in EXTINT mode.
664 if (kvm
->arch
.vapics_in_nmi_mode
> 0)
665 for (i
= 0; i
< KVM_MAX_VCPUS
; ++i
) {
666 vcpu
= kvm
->vcpus
[i
];
668 kvm_apic_nmi_wd_deliver(vcpu
);
672 void kvm_inject_pit_timer_irqs(struct kvm_vcpu
*vcpu
)
674 struct kvm_pit
*pit
= vcpu
->kvm
->arch
.vpit
;
675 struct kvm
*kvm
= vcpu
->kvm
;
676 struct kvm_kpit_state
*ps
;
680 ps
= &pit
->pit_state
;
682 /* Try to inject pending interrupts when
683 * last one has been acked.
685 spin_lock(&ps
->inject_lock
);
686 if (atomic_read(&ps
->pit_timer
.pending
) && ps
->irq_ack
) {
690 spin_unlock(&ps
->inject_lock
);
692 __inject_pit_timer_intr(kvm
);