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 int pit_get_count(struct kvm
*kvm
, int channel
)
103 struct kvm_kpit_channel_state
*c
=
104 &kvm
->arch
.vpit
->pit_state
.channels
[channel
];
108 WARN_ON(!mutex_is_locked(&kvm
->arch
.vpit
->pit_state
.lock
));
110 t
= ktime_to_ns(ktime_sub(ktime_get(), c
->count_load_time
));
111 d
= muldiv64(t
, KVM_PIT_FREQ
, NSEC_PER_SEC
);
118 counter
= (c
->count
- d
) & 0xffff;
121 /* XXX: may be incorrect for odd counts */
122 counter
= c
->count
- (mod_64((2 * d
), c
->count
));
125 counter
= c
->count
- mod_64(d
, c
->count
);
131 static int pit_get_out(struct kvm
*kvm
, int channel
)
133 struct kvm_kpit_channel_state
*c
=
134 &kvm
->arch
.vpit
->pit_state
.channels
[channel
];
138 WARN_ON(!mutex_is_locked(&kvm
->arch
.vpit
->pit_state
.lock
));
140 t
= ktime_to_ns(ktime_sub(ktime_get(), c
->count_load_time
));
141 d
= muldiv64(t
, KVM_PIT_FREQ
, NSEC_PER_SEC
);
146 out
= (d
>= c
->count
);
149 out
= (d
< c
->count
);
152 out
= ((mod_64(d
, c
->count
) == 0) && (d
!= 0));
155 out
= (mod_64(d
, c
->count
) < ((c
->count
+ 1) >> 1));
159 out
= (d
== c
->count
);
166 static void pit_latch_count(struct kvm
*kvm
, int channel
)
168 struct kvm_kpit_channel_state
*c
=
169 &kvm
->arch
.vpit
->pit_state
.channels
[channel
];
171 WARN_ON(!mutex_is_locked(&kvm
->arch
.vpit
->pit_state
.lock
));
173 if (!c
->count_latched
) {
174 c
->latched_count
= pit_get_count(kvm
, channel
);
175 c
->count_latched
= c
->rw_mode
;
179 static void pit_latch_status(struct kvm
*kvm
, int channel
)
181 struct kvm_kpit_channel_state
*c
=
182 &kvm
->arch
.vpit
->pit_state
.channels
[channel
];
184 WARN_ON(!mutex_is_locked(&kvm
->arch
.vpit
->pit_state
.lock
));
186 if (!c
->status_latched
) {
187 /* TODO: Return NULL COUNT (bit 6). */
188 c
->status
= ((pit_get_out(kvm
, channel
) << 7) |
192 c
->status_latched
= 1;
196 static int __pit_timer_fn(struct kvm_kpit_state
*ps
)
198 struct kvm_vcpu
*vcpu0
= ps
->pit
->kvm
->vcpus
[0];
199 struct kvm_kpit_timer
*pt
= &ps
->pit_timer
;
201 if (!atomic_inc_and_test(&pt
->pending
))
202 set_bit(KVM_REQ_PENDING_TIMER
, &vcpu0
->requests
);
205 atomic_set(&pt
->pending
, 1);
207 if (vcpu0
&& waitqueue_active(&vcpu0
->wq
))
208 wake_up_interruptible(&vcpu0
->wq
);
210 hrtimer_add_expires_ns(&pt
->timer
, pt
->period
);
211 pt
->scheduled
= hrtimer_get_expires_ns(&pt
->timer
);
213 ps
->channels
[0].count_load_time
= ktime_get();
215 return (pt
->period
== 0 ? 0 : 1);
218 int pit_has_pending_timer(struct kvm_vcpu
*vcpu
)
220 struct kvm_pit
*pit
= vcpu
->kvm
->arch
.vpit
;
222 if (pit
&& vcpu
->vcpu_id
== 0 && pit
->pit_state
.irq_ack
)
223 return atomic_read(&pit
->pit_state
.pit_timer
.pending
);
227 static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier
*kian
)
229 struct kvm_kpit_state
*ps
= container_of(kian
, struct kvm_kpit_state
,
231 spin_lock(&ps
->inject_lock
);
232 if (atomic_dec_return(&ps
->pit_timer
.pending
) < 0)
233 atomic_inc(&ps
->pit_timer
.pending
);
235 spin_unlock(&ps
->inject_lock
);
238 static enum hrtimer_restart
pit_timer_fn(struct hrtimer
*data
)
240 struct kvm_kpit_state
*ps
;
241 int restart_timer
= 0;
243 ps
= container_of(data
, struct kvm_kpit_state
, pit_timer
.timer
);
245 restart_timer
= __pit_timer_fn(ps
);
248 return HRTIMER_RESTART
;
250 return HRTIMER_NORESTART
;
253 void __kvm_migrate_pit_timer(struct kvm_vcpu
*vcpu
)
255 struct kvm_pit
*pit
= vcpu
->kvm
->arch
.vpit
;
256 struct hrtimer
*timer
;
258 if (vcpu
->vcpu_id
!= 0 || !pit
)
261 timer
= &pit
->pit_state
.pit_timer
.timer
;
262 if (hrtimer_cancel(timer
))
263 hrtimer_start_expires(timer
, HRTIMER_MODE_ABS
);
266 static void destroy_pit_timer(struct kvm_kpit_timer
*pt
)
268 pr_debug("pit: execute del timer!\n");
269 hrtimer_cancel(&pt
->timer
);
272 static void create_pit_timer(struct kvm_kpit_state
*ps
, u32 val
, int is_period
)
274 struct kvm_kpit_timer
*pt
= &ps
->pit_timer
;
277 interval
= muldiv64(val
, NSEC_PER_SEC
, KVM_PIT_FREQ
);
279 pr_debug("pit: create pit timer, interval is %llu nsec\n", interval
);
281 /* TODO The new value only affected after the retriggered */
282 hrtimer_cancel(&pt
->timer
);
283 pt
->period
= (is_period
== 0) ? 0 : interval
;
284 pt
->timer
.function
= pit_timer_fn
;
285 atomic_set(&pt
->pending
, 0);
288 hrtimer_start(&pt
->timer
, ktime_add_ns(ktime_get(), interval
),
292 static void pit_load_count(struct kvm
*kvm
, int channel
, u32 val
)
294 struct kvm_kpit_state
*ps
= &kvm
->arch
.vpit
->pit_state
;
296 WARN_ON(!mutex_is_locked(&ps
->lock
));
298 pr_debug("pit: load_count val is %d, channel is %d\n", val
, channel
);
301 * Though spec said the state of 8254 is undefined after power-up,
302 * seems some tricky OS like Windows XP depends on IRQ0 interrupt
304 * So here setting initialize rate for it, and not a specific number
309 ps
->channels
[channel
].count_load_time
= ktime_get();
310 ps
->channels
[channel
].count
= val
;
315 /* Two types of timer
316 * mode 1 is one shot, mode 2 is period, otherwise del timer */
317 switch (ps
->channels
[0].mode
) {
319 /* FIXME: enhance mode 4 precision */
321 create_pit_timer(ps
, val
, 0);
325 create_pit_timer(ps
, val
, 1);
328 destroy_pit_timer(&ps
->pit_timer
);
332 void kvm_pit_load_count(struct kvm
*kvm
, int channel
, u32 val
)
334 mutex_lock(&kvm
->arch
.vpit
->pit_state
.lock
);
335 pit_load_count(kvm
, channel
, val
);
336 mutex_unlock(&kvm
->arch
.vpit
->pit_state
.lock
);
339 static void pit_ioport_write(struct kvm_io_device
*this,
340 gpa_t addr
, int len
, const void *data
)
342 struct kvm_pit
*pit
= (struct kvm_pit
*)this->private;
343 struct kvm_kpit_state
*pit_state
= &pit
->pit_state
;
344 struct kvm
*kvm
= pit
->kvm
;
346 struct kvm_kpit_channel_state
*s
;
347 u32 val
= *(u32
*) data
;
350 addr
&= KVM_PIT_CHANNEL_MASK
;
352 mutex_lock(&pit_state
->lock
);
355 pr_debug("pit: write addr is 0x%x, len is %d, val is 0x%x\n",
356 (unsigned int)addr
, len
, val
);
361 /* Read-Back Command. */
362 for (channel
= 0; channel
< 3; channel
++) {
363 s
= &pit_state
->channels
[channel
];
364 if (val
& (2 << channel
)) {
366 pit_latch_count(kvm
, channel
);
368 pit_latch_status(kvm
, channel
);
372 /* Select Counter <channel>. */
373 s
= &pit_state
->channels
[channel
];
374 access
= (val
>> 4) & KVM_PIT_CHANNEL_MASK
;
376 pit_latch_count(kvm
, channel
);
379 s
->read_state
= access
;
380 s
->write_state
= access
;
381 s
->mode
= (val
>> 1) & 7;
389 s
= &pit_state
->channels
[addr
];
390 switch (s
->write_state
) {
393 pit_load_count(kvm
, addr
, val
);
396 pit_load_count(kvm
, addr
, val
<< 8);
399 s
->write_latch
= val
;
400 s
->write_state
= RW_STATE_WORD1
;
403 pit_load_count(kvm
, addr
, s
->write_latch
| (val
<< 8));
404 s
->write_state
= RW_STATE_WORD0
;
409 mutex_unlock(&pit_state
->lock
);
412 static void pit_ioport_read(struct kvm_io_device
*this,
413 gpa_t addr
, int len
, void *data
)
415 struct kvm_pit
*pit
= (struct kvm_pit
*)this->private;
416 struct kvm_kpit_state
*pit_state
= &pit
->pit_state
;
417 struct kvm
*kvm
= pit
->kvm
;
419 struct kvm_kpit_channel_state
*s
;
421 addr
&= KVM_PIT_CHANNEL_MASK
;
422 s
= &pit_state
->channels
[addr
];
424 mutex_lock(&pit_state
->lock
);
426 if (s
->status_latched
) {
427 s
->status_latched
= 0;
429 } else if (s
->count_latched
) {
430 switch (s
->count_latched
) {
433 ret
= s
->latched_count
& 0xff;
434 s
->count_latched
= 0;
437 ret
= s
->latched_count
>> 8;
438 s
->count_latched
= 0;
441 ret
= s
->latched_count
& 0xff;
442 s
->count_latched
= RW_STATE_MSB
;
446 switch (s
->read_state
) {
449 count
= pit_get_count(kvm
, addr
);
453 count
= pit_get_count(kvm
, addr
);
454 ret
= (count
>> 8) & 0xff;
457 count
= pit_get_count(kvm
, addr
);
459 s
->read_state
= RW_STATE_WORD1
;
462 count
= pit_get_count(kvm
, addr
);
463 ret
= (count
>> 8) & 0xff;
464 s
->read_state
= RW_STATE_WORD0
;
469 if (len
> sizeof(ret
))
471 memcpy(data
, (char *)&ret
, len
);
473 mutex_unlock(&pit_state
->lock
);
476 static int pit_in_range(struct kvm_io_device
*this, gpa_t addr
,
477 int len
, int is_write
)
479 return ((addr
>= KVM_PIT_BASE_ADDRESS
) &&
480 (addr
< KVM_PIT_BASE_ADDRESS
+ KVM_PIT_MEM_LENGTH
));
483 static void speaker_ioport_write(struct kvm_io_device
*this,
484 gpa_t addr
, int len
, const void *data
)
486 struct kvm_pit
*pit
= (struct kvm_pit
*)this->private;
487 struct kvm_kpit_state
*pit_state
= &pit
->pit_state
;
488 struct kvm
*kvm
= pit
->kvm
;
489 u32 val
= *(u32
*) data
;
491 mutex_lock(&pit_state
->lock
);
492 pit_state
->speaker_data_on
= (val
>> 1) & 1;
493 pit_set_gate(kvm
, 2, val
& 1);
494 mutex_unlock(&pit_state
->lock
);
497 static void speaker_ioport_read(struct kvm_io_device
*this,
498 gpa_t addr
, int len
, void *data
)
500 struct kvm_pit
*pit
= (struct kvm_pit
*)this->private;
501 struct kvm_kpit_state
*pit_state
= &pit
->pit_state
;
502 struct kvm
*kvm
= pit
->kvm
;
503 unsigned int refresh_clock
;
506 /* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
507 refresh_clock
= ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
509 mutex_lock(&pit_state
->lock
);
510 ret
= ((pit_state
->speaker_data_on
<< 1) | pit_get_gate(kvm
, 2) |
511 (pit_get_out(kvm
, 2) << 5) | (refresh_clock
<< 4));
512 if (len
> sizeof(ret
))
514 memcpy(data
, (char *)&ret
, len
);
515 mutex_unlock(&pit_state
->lock
);
518 static int speaker_in_range(struct kvm_io_device
*this, gpa_t addr
,
519 int len
, int is_write
)
521 return (addr
== KVM_SPEAKER_BASE_ADDRESS
);
524 void kvm_pit_reset(struct kvm_pit
*pit
)
527 struct kvm_kpit_channel_state
*c
;
529 mutex_lock(&pit
->pit_state
.lock
);
530 for (i
= 0; i
< 3; i
++) {
531 c
= &pit
->pit_state
.channels
[i
];
534 pit_load_count(pit
->kvm
, i
, 0);
536 mutex_unlock(&pit
->pit_state
.lock
);
538 atomic_set(&pit
->pit_state
.pit_timer
.pending
, 0);
539 pit
->pit_state
.irq_ack
= 1;
542 static void pit_mask_notifer(struct kvm_irq_mask_notifier
*kimn
, bool mask
)
544 struct kvm_pit
*pit
= container_of(kimn
, struct kvm_pit
, mask_notifier
);
547 atomic_set(&pit
->pit_state
.pit_timer
.pending
, 0);
548 pit
->pit_state
.irq_ack
= 1;
552 struct kvm_pit
*kvm_create_pit(struct kvm
*kvm
)
555 struct kvm_kpit_state
*pit_state
;
557 pit
= kzalloc(sizeof(struct kvm_pit
), GFP_KERNEL
);
561 pit
->irq_source_id
= kvm_request_irq_source_id(kvm
);
562 if (pit
->irq_source_id
< 0) {
567 mutex_init(&pit
->pit_state
.lock
);
568 mutex_lock(&pit
->pit_state
.lock
);
569 spin_lock_init(&pit
->pit_state
.inject_lock
);
571 /* Initialize PIO device */
572 pit
->dev
.read
= pit_ioport_read
;
573 pit
->dev
.write
= pit_ioport_write
;
574 pit
->dev
.in_range
= pit_in_range
;
575 pit
->dev
.private = pit
;
576 kvm_io_bus_register_dev(&kvm
->pio_bus
, &pit
->dev
);
578 pit
->speaker_dev
.read
= speaker_ioport_read
;
579 pit
->speaker_dev
.write
= speaker_ioport_write
;
580 pit
->speaker_dev
.in_range
= speaker_in_range
;
581 pit
->speaker_dev
.private = pit
;
582 kvm_io_bus_register_dev(&kvm
->pio_bus
, &pit
->speaker_dev
);
584 kvm
->arch
.vpit
= pit
;
587 pit_state
= &pit
->pit_state
;
588 pit_state
->pit
= pit
;
589 hrtimer_init(&pit_state
->pit_timer
.timer
,
590 CLOCK_MONOTONIC
, HRTIMER_MODE_ABS
);
591 pit_state
->irq_ack_notifier
.gsi
= 0;
592 pit_state
->irq_ack_notifier
.irq_acked
= kvm_pit_ack_irq
;
593 kvm_register_irq_ack_notifier(kvm
, &pit_state
->irq_ack_notifier
);
594 pit_state
->pit_timer
.reinject
= true;
595 mutex_unlock(&pit
->pit_state
.lock
);
599 pit
->mask_notifier
.func
= pit_mask_notifer
;
600 kvm_register_irq_mask_notifier(kvm
, 0, &pit
->mask_notifier
);
605 void kvm_free_pit(struct kvm
*kvm
)
607 struct hrtimer
*timer
;
609 if (kvm
->arch
.vpit
) {
610 kvm_unregister_irq_mask_notifier(kvm
, 0,
611 &kvm
->arch
.vpit
->mask_notifier
);
612 mutex_lock(&kvm
->arch
.vpit
->pit_state
.lock
);
613 timer
= &kvm
->arch
.vpit
->pit_state
.pit_timer
.timer
;
614 hrtimer_cancel(timer
);
615 kvm_free_irq_source_id(kvm
, kvm
->arch
.vpit
->irq_source_id
);
616 mutex_unlock(&kvm
->arch
.vpit
->pit_state
.lock
);
617 kfree(kvm
->arch
.vpit
);
621 static void __inject_pit_timer_intr(struct kvm
*kvm
)
623 struct kvm_vcpu
*vcpu
;
626 mutex_lock(&kvm
->lock
);
627 kvm_set_irq(kvm
, kvm
->arch
.vpit
->irq_source_id
, 0, 1);
628 kvm_set_irq(kvm
, kvm
->arch
.vpit
->irq_source_id
, 0, 0);
629 mutex_unlock(&kvm
->lock
);
632 * Provides NMI watchdog support via Virtual Wire mode.
633 * The route is: PIT -> PIC -> LVT0 in NMI mode.
635 * Note: Our Virtual Wire implementation is simplified, only
636 * propagating PIT interrupts to all VCPUs when they have set
637 * LVT0 to NMI delivery. Other PIC interrupts are just sent to
638 * VCPU0, and only if its LVT0 is in EXTINT mode.
640 if (kvm
->arch
.vapics_in_nmi_mode
> 0)
641 for (i
= 0; i
< KVM_MAX_VCPUS
; ++i
) {
642 vcpu
= kvm
->vcpus
[i
];
644 kvm_apic_nmi_wd_deliver(vcpu
);
648 void kvm_inject_pit_timer_irqs(struct kvm_vcpu
*vcpu
)
650 struct kvm_pit
*pit
= vcpu
->kvm
->arch
.vpit
;
651 struct kvm
*kvm
= vcpu
->kvm
;
652 struct kvm_kpit_state
*ps
;
656 ps
= &pit
->pit_state
;
658 /* Try to inject pending interrupts when
659 * last one has been acked.
661 spin_lock(&ps
->inject_lock
);
662 if (atomic_read(&ps
->pit_timer
.pending
) && ps
->irq_ack
) {
666 spin_unlock(&ps
->inject_lock
);
668 __inject_pit_timer_intr(kvm
);
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