1
2
3
4
5
6
7
8
9
10
11#include <linux/kernel.h>
12#include <linux/interrupt.h>
13#include <linux/clocksource.h>
14#include <linux/clockchips.h>
15#include <linux/gfp.h>
16#include <linux/slab.h>
17#include <linux/pvclock_gtod.h>
18#include <linux/timekeeper_internal.h>
19
20#include <asm/pvclock.h>
21#include <asm/xen/hypervisor.h>
22#include <asm/xen/hypercall.h>
23
24#include <xen/events.h>
25#include <xen/features.h>
26#include <xen/interface/xen.h>
27#include <xen/interface/vcpu.h>
28
29#include "xen-ops.h"
30
31
32#define TIMER_SLOP 100000
33
34static u64 xen_sched_clock_offset __read_mostly;
35
36
37static unsigned long xen_tsc_khz(void)
38{
39 struct pvclock_vcpu_time_info *info =
40 &HYPERVISOR_shared_info->vcpu_info[0].time;
41
42 setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
43 return pvclock_tsc_khz(info);
44}
45
46static u64 xen_clocksource_read(void)
47{
48 struct pvclock_vcpu_time_info *src;
49 u64 ret;
50
51 preempt_disable_notrace();
52 src = &__this_cpu_read(xen_vcpu)->time;
53 ret = pvclock_clocksource_read(src);
54 preempt_enable_notrace();
55 return ret;
56}
57
58static u64 xen_clocksource_get_cycles(struct clocksource *cs)
59{
60 return xen_clocksource_read();
61}
62
63static u64 xen_sched_clock(void)
64{
65 return xen_clocksource_read() - xen_sched_clock_offset;
66}
67
68static void xen_read_wallclock(struct timespec64 *ts)
69{
70 struct shared_info *s = HYPERVISOR_shared_info;
71 struct pvclock_wall_clock *wall_clock = &(s->wc);
72 struct pvclock_vcpu_time_info *vcpu_time;
73
74 vcpu_time = &get_cpu_var(xen_vcpu)->time;
75 pvclock_read_wallclock(wall_clock, vcpu_time, ts);
76 put_cpu_var(xen_vcpu);
77}
78
79static void xen_get_wallclock(struct timespec64 *now)
80{
81 xen_read_wallclock(now);
82}
83
84static int xen_set_wallclock(const struct timespec64 *now)
85{
86 return -ENODEV;
87}
88
89static int xen_pvclock_gtod_notify(struct notifier_block *nb,
90 unsigned long was_set, void *priv)
91{
92
93 static struct timespec64 next_sync;
94
95 struct xen_platform_op op;
96 struct timespec64 now;
97 struct timekeeper *tk = priv;
98 static bool settime64_supported = true;
99 int ret;
100
101 now.tv_sec = tk->xtime_sec;
102 now.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
103
104
105
106
107
108 if (!was_set && timespec64_compare(&now, &next_sync) < 0)
109 return NOTIFY_OK;
110
111again:
112 if (settime64_supported) {
113 op.cmd = XENPF_settime64;
114 op.u.settime64.mbz = 0;
115 op.u.settime64.secs = now.tv_sec;
116 op.u.settime64.nsecs = now.tv_nsec;
117 op.u.settime64.system_time = xen_clocksource_read();
118 } else {
119 op.cmd = XENPF_settime32;
120 op.u.settime32.secs = now.tv_sec;
121 op.u.settime32.nsecs = now.tv_nsec;
122 op.u.settime32.system_time = xen_clocksource_read();
123 }
124
125 ret = HYPERVISOR_platform_op(&op);
126
127 if (ret == -ENOSYS && settime64_supported) {
128 settime64_supported = false;
129 goto again;
130 }
131 if (ret < 0)
132 return NOTIFY_BAD;
133
134
135
136
137
138
139 next_sync = now;
140 next_sync.tv_sec += 11 * 60;
141
142 return NOTIFY_OK;
143}
144
145static struct notifier_block xen_pvclock_gtod_notifier = {
146 .notifier_call = xen_pvclock_gtod_notify,
147};
148
149static int xen_cs_enable(struct clocksource *cs)
150{
151 vclocks_set_used(VDSO_CLOCKMODE_PVCLOCK);
152 return 0;
153}
154
155static struct clocksource xen_clocksource __read_mostly = {
156 .name = "xen",
157 .rating = 400,
158 .read = xen_clocksource_get_cycles,
159 .mask = CLOCKSOURCE_MASK(64),
160 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
161 .enable = xen_cs_enable,
162};
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195static s64 get_abs_timeout(unsigned long delta)
196{
197 return xen_clocksource_read() + delta;
198}
199
200static int xen_timerop_shutdown(struct clock_event_device *evt)
201{
202
203 HYPERVISOR_set_timer_op(0);
204
205 return 0;
206}
207
208static int xen_timerop_set_next_event(unsigned long delta,
209 struct clock_event_device *evt)
210{
211 WARN_ON(!clockevent_state_oneshot(evt));
212
213 if (HYPERVISOR_set_timer_op(get_abs_timeout(delta)) < 0)
214 BUG();
215
216
217
218
219
220 return 0;
221}
222
223static struct clock_event_device xen_timerop_clockevent __ro_after_init = {
224 .name = "xen",
225 .features = CLOCK_EVT_FEAT_ONESHOT,
226
227 .max_delta_ns = 0xffffffff,
228 .max_delta_ticks = 0xffffffff,
229 .min_delta_ns = TIMER_SLOP,
230 .min_delta_ticks = TIMER_SLOP,
231
232 .mult = 1,
233 .shift = 0,
234 .rating = 500,
235
236 .set_state_shutdown = xen_timerop_shutdown,
237 .set_next_event = xen_timerop_set_next_event,
238};
239
240static int xen_vcpuop_shutdown(struct clock_event_device *evt)
241{
242 int cpu = smp_processor_id();
243
244 if (HYPERVISOR_vcpu_op(VCPUOP_stop_singleshot_timer, xen_vcpu_nr(cpu),
245 NULL) ||
246 HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, xen_vcpu_nr(cpu),
247 NULL))
248 BUG();
249
250 return 0;
251}
252
253static int xen_vcpuop_set_oneshot(struct clock_event_device *evt)
254{
255 int cpu = smp_processor_id();
256
257 if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, xen_vcpu_nr(cpu),
258 NULL))
259 BUG();
260
261 return 0;
262}
263
264static int xen_vcpuop_set_next_event(unsigned long delta,
265 struct clock_event_device *evt)
266{
267 int cpu = smp_processor_id();
268 struct vcpu_set_singleshot_timer single;
269 int ret;
270
271 WARN_ON(!clockevent_state_oneshot(evt));
272
273 single.timeout_abs_ns = get_abs_timeout(delta);
274
275 single.flags = 0;
276
277 ret = HYPERVISOR_vcpu_op(VCPUOP_set_singleshot_timer, xen_vcpu_nr(cpu),
278 &single);
279 BUG_ON(ret != 0);
280
281 return ret;
282}
283
284static struct clock_event_device xen_vcpuop_clockevent __ro_after_init = {
285 .name = "xen",
286 .features = CLOCK_EVT_FEAT_ONESHOT,
287
288 .max_delta_ns = 0xffffffff,
289 .max_delta_ticks = 0xffffffff,
290 .min_delta_ns = TIMER_SLOP,
291 .min_delta_ticks = TIMER_SLOP,
292
293 .mult = 1,
294 .shift = 0,
295 .rating = 500,
296
297 .set_state_shutdown = xen_vcpuop_shutdown,
298 .set_state_oneshot = xen_vcpuop_set_oneshot,
299 .set_next_event = xen_vcpuop_set_next_event,
300};
301
302static const struct clock_event_device *xen_clockevent =
303 &xen_timerop_clockevent;
304
305struct xen_clock_event_device {
306 struct clock_event_device evt;
307 char name[16];
308};
309static DEFINE_PER_CPU(struct xen_clock_event_device, xen_clock_events) = { .evt.irq = -1 };
310
311static irqreturn_t xen_timer_interrupt(int irq, void *dev_id)
312{
313 struct clock_event_device *evt = this_cpu_ptr(&xen_clock_events.evt);
314 irqreturn_t ret;
315
316 ret = IRQ_NONE;
317 if (evt->event_handler) {
318 evt->event_handler(evt);
319 ret = IRQ_HANDLED;
320 }
321
322 return ret;
323}
324
325void xen_teardown_timer(int cpu)
326{
327 struct clock_event_device *evt;
328 evt = &per_cpu(xen_clock_events, cpu).evt;
329
330 if (evt->irq >= 0) {
331 unbind_from_irqhandler(evt->irq, NULL);
332 evt->irq = -1;
333 }
334}
335
336void xen_setup_timer(int cpu)
337{
338 struct xen_clock_event_device *xevt = &per_cpu(xen_clock_events, cpu);
339 struct clock_event_device *evt = &xevt->evt;
340 int irq;
341
342 WARN(evt->irq >= 0, "IRQ%d for CPU%d is already allocated\n", evt->irq, cpu);
343 if (evt->irq >= 0)
344 xen_teardown_timer(cpu);
345
346 printk(KERN_INFO "installing Xen timer for CPU %d\n", cpu);
347
348 snprintf(xevt->name, sizeof(xevt->name), "timer%d", cpu);
349
350 irq = bind_virq_to_irqhandler(VIRQ_TIMER, cpu, xen_timer_interrupt,
351 IRQF_PERCPU|IRQF_NOBALANCING|IRQF_TIMER|
352 IRQF_FORCE_RESUME|IRQF_EARLY_RESUME,
353 xevt->name, NULL);
354 (void)xen_set_irq_priority(irq, XEN_IRQ_PRIORITY_MAX);
355
356 memcpy(evt, xen_clockevent, sizeof(*evt));
357
358 evt->cpumask = cpumask_of(cpu);
359 evt->irq = irq;
360}
361
362
363void xen_setup_cpu_clockevents(void)
364{
365 clockevents_register_device(this_cpu_ptr(&xen_clock_events.evt));
366}
367
368void xen_timer_resume(void)
369{
370 int cpu;
371
372 if (xen_clockevent != &xen_vcpuop_clockevent)
373 return;
374
375 for_each_online_cpu(cpu) {
376 if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer,
377 xen_vcpu_nr(cpu), NULL))
378 BUG();
379 }
380}
381
382static struct pvclock_vsyscall_time_info *xen_clock __read_mostly;
383static u64 xen_clock_value_saved;
384
385void xen_save_time_memory_area(void)
386{
387 struct vcpu_register_time_memory_area t;
388 int ret;
389
390 xen_clock_value_saved = xen_clocksource_read() - xen_sched_clock_offset;
391
392 if (!xen_clock)
393 return;
394
395 t.addr.v = NULL;
396
397 ret = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_time_memory_area, 0, &t);
398 if (ret != 0)
399 pr_notice("Cannot save secondary vcpu_time_info (err %d)",
400 ret);
401 else
402 clear_page(xen_clock);
403}
404
405void xen_restore_time_memory_area(void)
406{
407 struct vcpu_register_time_memory_area t;
408 int ret;
409
410 if (!xen_clock)
411 goto out;
412
413 t.addr.v = &xen_clock->pvti;
414
415 ret = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_time_memory_area, 0, &t);
416
417
418
419
420
421
422
423
424
425
426 if (ret != 0)
427 pr_notice("Cannot restore secondary vcpu_time_info (err %d)",
428 ret);
429
430out:
431
432 pvclock_resume();
433 xen_sched_clock_offset = xen_clocksource_read() - xen_clock_value_saved;
434}
435
436static void xen_setup_vsyscall_time_info(void)
437{
438 struct vcpu_register_time_memory_area t;
439 struct pvclock_vsyscall_time_info *ti;
440 int ret;
441
442 ti = (struct pvclock_vsyscall_time_info *)get_zeroed_page(GFP_KERNEL);
443 if (!ti)
444 return;
445
446 t.addr.v = &ti->pvti;
447
448 ret = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_time_memory_area, 0, &t);
449 if (ret) {
450 pr_notice("xen: VDSO_CLOCKMODE_PVCLOCK not supported (err %d)\n", ret);
451 free_page((unsigned long)ti);
452 return;
453 }
454
455
456
457
458
459
460 if (!(ti->pvti.flags & PVCLOCK_TSC_STABLE_BIT)) {
461 t.addr.v = NULL;
462 ret = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_time_memory_area,
463 0, &t);
464 if (!ret)
465 free_page((unsigned long)ti);
466
467 pr_notice("xen: VDSO_CLOCKMODE_PVCLOCK not supported (tsc unstable)\n");
468 return;
469 }
470
471 xen_clock = ti;
472 pvclock_set_pvti_cpu0_va(xen_clock);
473
474 xen_clocksource.vdso_clock_mode = VDSO_CLOCKMODE_PVCLOCK;
475}
476
477static void __init xen_time_init(void)
478{
479 struct pvclock_vcpu_time_info *pvti;
480 int cpu = smp_processor_id();
481 struct timespec64 tp;
482
483
484 if (xen_initial_domain())
485 xen_clocksource.rating = 275;
486
487 clocksource_register_hz(&xen_clocksource, NSEC_PER_SEC);
488
489 if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, xen_vcpu_nr(cpu),
490 NULL) == 0) {
491
492
493 printk(KERN_DEBUG "Xen: using vcpuop timer interface\n");
494 xen_clockevent = &xen_vcpuop_clockevent;
495 }
496
497
498 xen_read_wallclock(&tp);
499 do_settimeofday64(&tp);
500
501 setup_force_cpu_cap(X86_FEATURE_TSC);
502
503
504
505
506
507 pvti = &__this_cpu_read(xen_vcpu)->time;
508 if (pvti->flags & PVCLOCK_TSC_STABLE_BIT) {
509 pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT);
510 xen_setup_vsyscall_time_info();
511 }
512
513 xen_setup_runstate_info(cpu);
514 xen_setup_timer(cpu);
515 xen_setup_cpu_clockevents();
516
517 xen_time_setup_guest();
518
519 if (xen_initial_domain())
520 pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier);
521}
522
523static void __init xen_init_time_common(void)
524{
525 xen_sched_clock_offset = xen_clocksource_read();
526 static_call_update(pv_steal_clock, xen_steal_clock);
527 paravirt_set_sched_clock(xen_sched_clock);
528
529 x86_platform.calibrate_tsc = xen_tsc_khz;
530 x86_platform.get_wallclock = xen_get_wallclock;
531}
532
533void __init xen_init_time_ops(void)
534{
535 xen_init_time_common();
536
537 x86_init.timers.timer_init = xen_time_init;
538 x86_init.timers.setup_percpu_clockev = x86_init_noop;
539 x86_cpuinit.setup_percpu_clockev = x86_init_noop;
540
541
542 if (!xen_initial_domain())
543 x86_platform.set_wallclock = xen_set_wallclock;
544}
545
546#ifdef CONFIG_XEN_PVHVM
547static void xen_hvm_setup_cpu_clockevents(void)
548{
549 int cpu = smp_processor_id();
550 xen_setup_runstate_info(cpu);
551
552
553
554
555
556 xen_setup_cpu_clockevents();
557}
558
559void __init xen_hvm_init_time_ops(void)
560{
561
562
563
564
565
566 if (!xen_have_vector_callback)
567 return;
568
569 if (!xen_feature(XENFEAT_hvm_safe_pvclock)) {
570 pr_info("Xen doesn't support pvclock on HVM, disable pv timer");
571 return;
572 }
573
574 xen_init_time_common();
575
576 x86_init.timers.setup_percpu_clockev = xen_time_init;
577 x86_cpuinit.setup_percpu_clockev = xen_hvm_setup_cpu_clockevents;
578
579 x86_platform.set_wallclock = xen_set_wallclock;
580}
581#endif
582
583
584static int __init parse_xen_timer_slop(char *ptr)
585{
586 unsigned long slop = memparse(ptr, NULL);
587
588 xen_timerop_clockevent.min_delta_ns = slop;
589 xen_timerop_clockevent.min_delta_ticks = slop;
590 xen_vcpuop_clockevent.min_delta_ns = slop;
591 xen_vcpuop_clockevent.min_delta_ticks = slop;
592
593 return 0;
594}
595early_param("xen_timer_slop", parse_xen_timer_slop);
596