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Commit | Line | Data |
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15c84731 JF |
1 | /* |
2 | * Xen time implementation. | |
3 | * | |
4 | * This is implemented in terms of a clocksource driver which uses | |
5 | * the hypervisor clock as a nanosecond timebase, and a clockevent | |
6 | * driver which uses the hypervisor's timer mechanism. | |
7 | * | |
8 | * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 | |
9 | */ | |
10 | #include <linux/kernel.h> | |
11 | #include <linux/interrupt.h> | |
12 | #include <linux/clocksource.h> | |
13 | #include <linux/clockchips.h> | |
5a0e3ad6 | 14 | #include <linux/gfp.h> |
c9d76a24 | 15 | #include <linux/slab.h> |
5584880e | 16 | #include <linux/pvclock_gtod.h> |
76096863 | 17 | #include <linux/timekeeper_internal.h> |
15c84731 | 18 | |
1c7b67f7 | 19 | #include <asm/pvclock.h> |
15c84731 JF |
20 | #include <asm/xen/hypervisor.h> |
21 | #include <asm/xen/hypercall.h> | |
22 | ||
23 | #include <xen/events.h> | |
409771d2 | 24 | #include <xen/features.h> |
15c84731 JF |
25 | #include <xen/interface/xen.h> |
26 | #include <xen/interface/vcpu.h> | |
27 | ||
28 | #include "xen-ops.h" | |
29 | ||
15c84731 JF |
30 | /* Xen may fire a timer up to this many ns early */ |
31 | #define TIMER_SLOP 100000 | |
f91a8b44 | 32 | |
e93ef949 | 33 | /* Get the TSC speed from Xen */ |
409771d2 | 34 | static unsigned long xen_tsc_khz(void) |
15c84731 | 35 | { |
3807f345 | 36 | struct pvclock_vcpu_time_info *info = |
15c84731 JF |
37 | &HYPERVISOR_shared_info->vcpu_info[0].time; |
38 | ||
3807f345 | 39 | return pvclock_tsc_khz(info); |
15c84731 JF |
40 | } |
41 | ||
a5a1d1c2 | 42 | u64 xen_clocksource_read(void) |
15c84731 | 43 | { |
1c7b67f7 | 44 | struct pvclock_vcpu_time_info *src; |
a5a1d1c2 | 45 | u64 ret; |
15c84731 | 46 | |
f1c39625 | 47 | preempt_disable_notrace(); |
3251f20b | 48 | src = &__this_cpu_read(xen_vcpu)->time; |
1c7b67f7 | 49 | ret = pvclock_clocksource_read(src); |
f1c39625 | 50 | preempt_enable_notrace(); |
15c84731 JF |
51 | return ret; |
52 | } | |
53 | ||
a5a1d1c2 | 54 | static u64 xen_clocksource_get_cycles(struct clocksource *cs) |
8e19608e MD |
55 | { |
56 | return xen_clocksource_read(); | |
57 | } | |
58 | ||
15c84731 JF |
59 | static void xen_read_wallclock(struct timespec *ts) |
60 | { | |
1c7b67f7 GH |
61 | struct shared_info *s = HYPERVISOR_shared_info; |
62 | struct pvclock_wall_clock *wall_clock = &(s->wc); | |
63 | struct pvclock_vcpu_time_info *vcpu_time; | |
15c84731 | 64 | |
1c7b67f7 GH |
65 | vcpu_time = &get_cpu_var(xen_vcpu)->time; |
66 | pvclock_read_wallclock(wall_clock, vcpu_time, ts); | |
67 | put_cpu_var(xen_vcpu); | |
15c84731 JF |
68 | } |
69 | ||
3565184e | 70 | static void xen_get_wallclock(struct timespec *now) |
15c84731 | 71 | { |
3565184e | 72 | xen_read_wallclock(now); |
15c84731 | 73 | } |
15c84731 | 74 | |
3565184e | 75 | static int xen_set_wallclock(const struct timespec *now) |
15c84731 | 76 | { |
47433b8c | 77 | return -1; |
15c84731 JF |
78 | } |
79 | ||
47433b8c DV |
80 | static int xen_pvclock_gtod_notify(struct notifier_block *nb, |
81 | unsigned long was_set, void *priv) | |
15c84731 | 82 | { |
47433b8c | 83 | /* Protected by the calling core code serialization */ |
187b26a9 | 84 | static struct timespec64 next_sync; |
5584880e | 85 | |
fdb9eb9f | 86 | struct xen_platform_op op; |
76096863 SS |
87 | struct timespec64 now; |
88 | struct timekeeper *tk = priv; | |
89 | static bool settime64_supported = true; | |
90 | int ret; | |
fdb9eb9f | 91 | |
76096863 SS |
92 | now.tv_sec = tk->xtime_sec; |
93 | now.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift); | |
5584880e | 94 | |
47433b8c DV |
95 | /* |
96 | * We only take the expensive HV call when the clock was set | |
97 | * or when the 11 minutes RTC synchronization time elapsed. | |
98 | */ | |
187b26a9 | 99 | if (!was_set && timespec64_compare(&now, &next_sync) < 0) |
47433b8c | 100 | return NOTIFY_OK; |
fdb9eb9f | 101 | |
76096863 SS |
102 | again: |
103 | if (settime64_supported) { | |
104 | op.cmd = XENPF_settime64; | |
105 | op.u.settime64.mbz = 0; | |
106 | op.u.settime64.secs = now.tv_sec; | |
107 | op.u.settime64.nsecs = now.tv_nsec; | |
108 | op.u.settime64.system_time = xen_clocksource_read(); | |
109 | } else { | |
110 | op.cmd = XENPF_settime32; | |
111 | op.u.settime32.secs = now.tv_sec; | |
112 | op.u.settime32.nsecs = now.tv_nsec; | |
113 | op.u.settime32.system_time = xen_clocksource_read(); | |
114 | } | |
115 | ||
116 | ret = HYPERVISOR_platform_op(&op); | |
117 | ||
118 | if (ret == -ENOSYS && settime64_supported) { | |
119 | settime64_supported = false; | |
120 | goto again; | |
121 | } | |
122 | if (ret < 0) | |
123 | return NOTIFY_BAD; | |
fdb9eb9f | 124 | |
47433b8c DV |
125 | /* |
126 | * Move the next drift compensation time 11 minutes | |
127 | * ahead. That's emulating the sync_cmos_clock() update for | |
128 | * the hardware RTC. | |
129 | */ | |
130 | next_sync = now; | |
131 | next_sync.tv_sec += 11 * 60; | |
132 | ||
5584880e | 133 | return NOTIFY_OK; |
15c84731 JF |
134 | } |
135 | ||
5584880e DV |
136 | static struct notifier_block xen_pvclock_gtod_notifier = { |
137 | .notifier_call = xen_pvclock_gtod_notify, | |
138 | }; | |
139 | ||
15c84731 JF |
140 | static struct clocksource xen_clocksource __read_mostly = { |
141 | .name = "xen", | |
142 | .rating = 400, | |
8e19608e | 143 | .read = xen_clocksource_get_cycles, |
15c84731 | 144 | .mask = ~0, |
15c84731 JF |
145 | .flags = CLOCK_SOURCE_IS_CONTINUOUS, |
146 | }; | |
147 | ||
148 | /* | |
149 | Xen clockevent implementation | |
150 | ||
151 | Xen has two clockevent implementations: | |
152 | ||
153 | The old timer_op one works with all released versions of Xen prior | |
154 | to version 3.0.4. This version of the hypervisor provides a | |
155 | single-shot timer with nanosecond resolution. However, sharing the | |
156 | same event channel is a 100Hz tick which is delivered while the | |
157 | vcpu is running. We don't care about or use this tick, but it will | |
158 | cause the core time code to think the timer fired too soon, and | |
159 | will end up resetting it each time. It could be filtered, but | |
160 | doing so has complications when the ktime clocksource is not yet | |
161 | the xen clocksource (ie, at boot time). | |
162 | ||
163 | The new vcpu_op-based timer interface allows the tick timer period | |
164 | to be changed or turned off. The tick timer is not useful as a | |
165 | periodic timer because events are only delivered to running vcpus. | |
166 | The one-shot timer can report when a timeout is in the past, so | |
167 | set_next_event is capable of returning -ETIME when appropriate. | |
168 | This interface is used when available. | |
169 | */ | |
170 | ||
171 | ||
172 | /* | |
173 | Get a hypervisor absolute time. In theory we could maintain an | |
174 | offset between the kernel's time and the hypervisor's time, and | |
175 | apply that to a kernel's absolute timeout. Unfortunately the | |
176 | hypervisor and kernel times can drift even if the kernel is using | |
177 | the Xen clocksource, because ntp can warp the kernel's clocksource. | |
178 | */ | |
179 | static s64 get_abs_timeout(unsigned long delta) | |
180 | { | |
181 | return xen_clocksource_read() + delta; | |
182 | } | |
183 | ||
955381dd | 184 | static int xen_timerop_shutdown(struct clock_event_device *evt) |
15c84731 | 185 | { |
955381dd VK |
186 | /* cancel timeout */ |
187 | HYPERVISOR_set_timer_op(0); | |
188 | ||
189 | return 0; | |
15c84731 JF |
190 | } |
191 | ||
192 | static int xen_timerop_set_next_event(unsigned long delta, | |
193 | struct clock_event_device *evt) | |
194 | { | |
955381dd | 195 | WARN_ON(!clockevent_state_oneshot(evt)); |
15c84731 JF |
196 | |
197 | if (HYPERVISOR_set_timer_op(get_abs_timeout(delta)) < 0) | |
198 | BUG(); | |
199 | ||
200 | /* We may have missed the deadline, but there's no real way of | |
201 | knowing for sure. If the event was in the past, then we'll | |
202 | get an immediate interrupt. */ | |
203 | ||
204 | return 0; | |
205 | } | |
206 | ||
207 | static const struct clock_event_device xen_timerop_clockevent = { | |
955381dd VK |
208 | .name = "xen", |
209 | .features = CLOCK_EVT_FEAT_ONESHOT, | |
15c84731 | 210 | |
955381dd VK |
211 | .max_delta_ns = 0xffffffff, |
212 | .min_delta_ns = TIMER_SLOP, | |
15c84731 | 213 | |
955381dd VK |
214 | .mult = 1, |
215 | .shift = 0, | |
216 | .rating = 500, | |
15c84731 | 217 | |
955381dd VK |
218 | .set_state_shutdown = xen_timerop_shutdown, |
219 | .set_next_event = xen_timerop_set_next_event, | |
15c84731 JF |
220 | }; |
221 | ||
955381dd VK |
222 | static int xen_vcpuop_shutdown(struct clock_event_device *evt) |
223 | { | |
224 | int cpu = smp_processor_id(); | |
15c84731 | 225 | |
ad5475f9 VK |
226 | if (HYPERVISOR_vcpu_op(VCPUOP_stop_singleshot_timer, xen_vcpu_nr(cpu), |
227 | NULL) || | |
228 | HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, xen_vcpu_nr(cpu), | |
229 | NULL)) | |
955381dd | 230 | BUG(); |
15c84731 | 231 | |
955381dd VK |
232 | return 0; |
233 | } | |
234 | ||
235 | static int xen_vcpuop_set_oneshot(struct clock_event_device *evt) | |
15c84731 JF |
236 | { |
237 | int cpu = smp_processor_id(); | |
238 | ||
ad5475f9 VK |
239 | if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, xen_vcpu_nr(cpu), |
240 | NULL)) | |
955381dd VK |
241 | BUG(); |
242 | ||
243 | return 0; | |
15c84731 JF |
244 | } |
245 | ||
246 | static int xen_vcpuop_set_next_event(unsigned long delta, | |
247 | struct clock_event_device *evt) | |
248 | { | |
249 | int cpu = smp_processor_id(); | |
250 | struct vcpu_set_singleshot_timer single; | |
251 | int ret; | |
252 | ||
955381dd | 253 | WARN_ON(!clockevent_state_oneshot(evt)); |
15c84731 JF |
254 | |
255 | single.timeout_abs_ns = get_abs_timeout(delta); | |
c06b6d70 SS |
256 | /* Get an event anyway, even if the timeout is already expired */ |
257 | single.flags = 0; | |
15c84731 | 258 | |
ad5475f9 VK |
259 | ret = HYPERVISOR_vcpu_op(VCPUOP_set_singleshot_timer, xen_vcpu_nr(cpu), |
260 | &single); | |
c06b6d70 | 261 | BUG_ON(ret != 0); |
15c84731 JF |
262 | |
263 | return ret; | |
264 | } | |
265 | ||
266 | static const struct clock_event_device xen_vcpuop_clockevent = { | |
267 | .name = "xen", | |
268 | .features = CLOCK_EVT_FEAT_ONESHOT, | |
269 | ||
270 | .max_delta_ns = 0xffffffff, | |
271 | .min_delta_ns = TIMER_SLOP, | |
272 | ||
273 | .mult = 1, | |
274 | .shift = 0, | |
275 | .rating = 500, | |
276 | ||
955381dd VK |
277 | .set_state_shutdown = xen_vcpuop_shutdown, |
278 | .set_state_oneshot = xen_vcpuop_set_oneshot, | |
15c84731 JF |
279 | .set_next_event = xen_vcpuop_set_next_event, |
280 | }; | |
281 | ||
282 | static const struct clock_event_device *xen_clockevent = | |
283 | &xen_timerop_clockevent; | |
31620a19 KRW |
284 | |
285 | struct xen_clock_event_device { | |
286 | struct clock_event_device evt; | |
7be0772d | 287 | char name[16]; |
31620a19 KRW |
288 | }; |
289 | static DEFINE_PER_CPU(struct xen_clock_event_device, xen_clock_events) = { .evt.irq = -1 }; | |
15c84731 JF |
290 | |
291 | static irqreturn_t xen_timer_interrupt(int irq, void *dev_id) | |
292 | { | |
89cbc767 | 293 | struct clock_event_device *evt = this_cpu_ptr(&xen_clock_events.evt); |
15c84731 JF |
294 | irqreturn_t ret; |
295 | ||
296 | ret = IRQ_NONE; | |
297 | if (evt->event_handler) { | |
298 | evt->event_handler(evt); | |
299 | ret = IRQ_HANDLED; | |
300 | } | |
301 | ||
302 | return ret; | |
303 | } | |
304 | ||
09e99da7 KRW |
305 | void xen_teardown_timer(int cpu) |
306 | { | |
307 | struct clock_event_device *evt; | |
308 | BUG_ON(cpu == 0); | |
309 | evt = &per_cpu(xen_clock_events, cpu).evt; | |
310 | ||
311 | if (evt->irq >= 0) { | |
312 | unbind_from_irqhandler(evt->irq, NULL); | |
313 | evt->irq = -1; | |
09e99da7 KRW |
314 | } |
315 | } | |
316 | ||
f87e4cac | 317 | void xen_setup_timer(int cpu) |
15c84731 | 318 | { |
7be0772d VK |
319 | struct xen_clock_event_device *xevt = &per_cpu(xen_clock_events, cpu); |
320 | struct clock_event_device *evt = &xevt->evt; | |
15c84731 JF |
321 | int irq; |
322 | ||
ef35a4e6 | 323 | WARN(evt->irq >= 0, "IRQ%d for CPU%d is already allocated\n", evt->irq, cpu); |
09e99da7 KRW |
324 | if (evt->irq >= 0) |
325 | xen_teardown_timer(cpu); | |
ef35a4e6 | 326 | |
15c84731 JF |
327 | printk(KERN_INFO "installing Xen timer for CPU %d\n", cpu); |
328 | ||
7be0772d | 329 | snprintf(xevt->name, sizeof(xevt->name), "timer%d", cpu); |
15c84731 JF |
330 | |
331 | irq = bind_virq_to_irqhandler(VIRQ_TIMER, cpu, xen_timer_interrupt, | |
9d71cee6 | 332 | IRQF_PERCPU|IRQF_NOBALANCING|IRQF_TIMER| |
8d5999df | 333 | IRQF_FORCE_RESUME|IRQF_EARLY_RESUME, |
7be0772d | 334 | xevt->name, NULL); |
8785c676 | 335 | (void)xen_set_irq_priority(irq, XEN_IRQ_PRIORITY_MAX); |
15c84731 | 336 | |
15c84731 JF |
337 | memcpy(evt, xen_clockevent, sizeof(*evt)); |
338 | ||
320ab2b0 | 339 | evt->cpumask = cpumask_of(cpu); |
15c84731 | 340 | evt->irq = irq; |
f87e4cac JF |
341 | } |
342 | ||
d68d82af | 343 | |
f87e4cac JF |
344 | void xen_setup_cpu_clockevents(void) |
345 | { | |
89cbc767 | 346 | clockevents_register_device(this_cpu_ptr(&xen_clock_events.evt)); |
15c84731 JF |
347 | } |
348 | ||
d07af1f0 JF |
349 | void xen_timer_resume(void) |
350 | { | |
351 | int cpu; | |
352 | ||
e7a3481c JF |
353 | pvclock_resume(); |
354 | ||
d07af1f0 JF |
355 | if (xen_clockevent != &xen_vcpuop_clockevent) |
356 | return; | |
357 | ||
358 | for_each_online_cpu(cpu) { | |
ad5475f9 VK |
359 | if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, |
360 | xen_vcpu_nr(cpu), NULL)) | |
d07af1f0 JF |
361 | BUG(); |
362 | } | |
363 | } | |
364 | ||
fb6ce5de | 365 | static const struct pv_time_ops xen_time_ops __initconst = { |
ca50a5f3 | 366 | .sched_clock = xen_clocksource_read, |
d34c30cc | 367 | .steal_clock = xen_steal_clock, |
409771d2 SS |
368 | }; |
369 | ||
fb6ce5de | 370 | static void __init xen_time_init(void) |
15c84731 JF |
371 | { |
372 | int cpu = smp_processor_id(); | |
c4507257 | 373 | struct timespec tp; |
15c84731 | 374 | |
94dd85f6 PI |
375 | /* As Dom0 is never moved, no penalty on using TSC there */ |
376 | if (xen_initial_domain()) | |
377 | xen_clocksource.rating = 275; | |
378 | ||
b01cc1b0 | 379 | clocksource_register_hz(&xen_clocksource, NSEC_PER_SEC); |
15c84731 | 380 | |
ad5475f9 VK |
381 | if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, xen_vcpu_nr(cpu), |
382 | NULL) == 0) { | |
f91a8b44 | 383 | /* Successfully turned off 100Hz tick, so we have the |
15c84731 JF |
384 | vcpuop-based timer interface */ |
385 | printk(KERN_DEBUG "Xen: using vcpuop timer interface\n"); | |
386 | xen_clockevent = &xen_vcpuop_clockevent; | |
387 | } | |
388 | ||
389 | /* Set initial system time with full resolution */ | |
c4507257 JS |
390 | xen_read_wallclock(&tp); |
391 | do_settimeofday(&tp); | |
15c84731 | 392 | |
404ee5b1 | 393 | setup_force_cpu_cap(X86_FEATURE_TSC); |
15c84731 | 394 | |
be012920 | 395 | xen_setup_runstate_info(cpu); |
15c84731 | 396 | xen_setup_timer(cpu); |
f87e4cac | 397 | xen_setup_cpu_clockevents(); |
5584880e | 398 | |
ecb23dc6 JG |
399 | xen_time_setup_guest(); |
400 | ||
5584880e DV |
401 | if (xen_initial_domain()) |
402 | pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier); | |
15c84731 | 403 | } |
409771d2 | 404 | |
fb6ce5de | 405 | void __init xen_init_time_ops(void) |
409771d2 SS |
406 | { |
407 | pv_time_ops = xen_time_ops; | |
408 | ||
409 | x86_init.timers.timer_init = xen_time_init; | |
410 | x86_init.timers.setup_percpu_clockev = x86_init_noop; | |
411 | x86_cpuinit.setup_percpu_clockev = x86_init_noop; | |
412 | ||
413 | x86_platform.calibrate_tsc = xen_tsc_khz; | |
414 | x86_platform.get_wallclock = xen_get_wallclock; | |
47433b8c DV |
415 | /* Dom0 uses the native method to set the hardware RTC. */ |
416 | if (!xen_initial_domain()) | |
417 | x86_platform.set_wallclock = xen_set_wallclock; | |
409771d2 SS |
418 | } |
419 | ||
ca65f9fc | 420 | #ifdef CONFIG_XEN_PVHVM |
409771d2 SS |
421 | static void xen_hvm_setup_cpu_clockevents(void) |
422 | { | |
423 | int cpu = smp_processor_id(); | |
424 | xen_setup_runstate_info(cpu); | |
7918c92a KRW |
425 | /* |
426 | * xen_setup_timer(cpu) - snprintf is bad in atomic context. Hence | |
427 | * doing it xen_hvm_cpu_notify (which gets called by smp_init during | |
428 | * early bootup and also during CPU hotplug events). | |
429 | */ | |
409771d2 SS |
430 | xen_setup_cpu_clockevents(); |
431 | } | |
432 | ||
fb6ce5de | 433 | void __init xen_hvm_init_time_ops(void) |
409771d2 | 434 | { |
409771d2 SS |
435 | if (!xen_feature(XENFEAT_hvm_safe_pvclock)) { |
436 | printk(KERN_INFO "Xen doesn't support pvclock on HVM," | |
437 | "disable pv timer\n"); | |
438 | return; | |
439 | } | |
440 | ||
441 | pv_time_ops = xen_time_ops; | |
442 | x86_init.timers.setup_percpu_clockev = xen_time_init; | |
443 | x86_cpuinit.setup_percpu_clockev = xen_hvm_setup_cpu_clockevents; | |
444 | ||
445 | x86_platform.calibrate_tsc = xen_tsc_khz; | |
446 | x86_platform.get_wallclock = xen_get_wallclock; | |
447 | x86_platform.set_wallclock = xen_set_wallclock; | |
448 | } | |
ca65f9fc | 449 | #endif |