| 1 | /* $NetBSD: clock.c,v 1.64 2016/06/12 09:08:09 jnemeth Exp $ */ |
| 2 | |
| 3 | /* |
| 4 | * |
| 5 | * Copyright (c) 2004 Christian Limpach. |
| 6 | * All rights reserved. |
| 7 | * |
| 8 | * Redistribution and use in source and binary forms, with or without |
| 9 | * modification, are permitted provided that the following conditions |
| 10 | * are met: |
| 11 | * 1. Redistributions of source code must retain the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer. |
| 13 | * 2. Redistributions in binary form must reproduce the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer in the |
| 15 | * documentation and/or other materials provided with the distribution. |
| 16 | * |
| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 27 | */ |
| 28 | |
| 29 | #include "opt_xen.h" |
| 30 | |
| 31 | #include <sys/cdefs.h> |
| 32 | __KERNEL_RCSID(0, "$NetBSD: clock.c,v 1.64 2016/06/12 09:08:09 jnemeth Exp $" ); |
| 33 | |
| 34 | #include <sys/param.h> |
| 35 | #include <sys/systm.h> |
| 36 | #include <sys/time.h> |
| 37 | #include <sys/timetc.h> |
| 38 | #include <sys/timevar.h> |
| 39 | #include <sys/kernel.h> |
| 40 | #include <sys/device.h> |
| 41 | #include <sys/sysctl.h> |
| 42 | |
| 43 | #include <xen/xen.h> |
| 44 | #include <xen/hypervisor.h> |
| 45 | #include <xen/evtchn.h> |
| 46 | #include <xen/xen-public/vcpu.h> |
| 47 | #include <machine/cpu_counter.h> |
| 48 | |
| 49 | #include <dev/clock_subr.h> |
| 50 | #include <x86/rtc.h> |
| 51 | |
| 52 | static int xen_timer_handler(void *, struct intrframe *); |
| 53 | |
| 54 | /* A timecounter: Xen system_time extrapolated with a TSC. */ |
| 55 | u_int xen_get_timecount(struct timecounter*); |
| 56 | static struct timecounter xen_timecounter = { |
| 57 | .tc_get_timecount = xen_get_timecount, |
| 58 | .tc_poll_pps = NULL, |
| 59 | .tc_counter_mask = ~0U, |
| 60 | .tc_frequency = 1000000000ULL, |
| 61 | .tc_name = "xen_system_time" , |
| 62 | .tc_quality = 10000 /* |
| 63 | * This needs to take precedence over any hardware |
| 64 | * timecounters (e.g., ACPI in Xen3 dom0), because |
| 65 | * they can't correct for Xen scheduling latency. |
| 66 | */ |
| 67 | }; |
| 68 | |
| 69 | /* These are periodically updated in shared_info, and then copied here. */ |
| 70 | struct shadow { |
| 71 | uint64_t tsc_stamp; |
| 72 | uint64_t system_time; |
| 73 | unsigned long time_version; /* XXXSMP */ |
| 74 | uint32_t freq_mul; |
| 75 | int8_t freq_shift; |
| 76 | struct timespec ts; |
| 77 | }; |
| 78 | |
| 79 | /* Protects volatile variables ci_shadow & xen_clock_bias */ |
| 80 | static kmutex_t tmutex; |
| 81 | |
| 82 | /* Per CPU shadow time values */ |
| 83 | static volatile struct shadow ci_shadow[MAXCPUS]; |
| 84 | |
| 85 | /* The time when the last hardclock(9) call should have taken place, |
| 86 | * per cpu. |
| 87 | */ |
| 88 | static volatile uint64_t vcpu_system_time[MAXCPUS]; |
| 89 | |
| 90 | /* |
| 91 | * The clock (as returned by xen_get_timecount) may need to be held |
| 92 | * back to maintain the illusion that hardclock(9) was called when it |
| 93 | * was supposed to be, not when Xen got around to scheduling us. |
| 94 | */ |
| 95 | static volatile uint64_t xen_clock_bias[MAXCPUS]; |
| 96 | |
| 97 | #ifdef DOM0OPS |
| 98 | /* If we're dom0, send our time to Xen every minute or so. */ |
| 99 | int xen_timepush_ticks = 0; |
| 100 | static callout_t xen_timepush_co; |
| 101 | #endif |
| 102 | |
| 103 | #define NS_PER_TICK (1000000000ULL/hz) |
| 104 | |
| 105 | /* |
| 106 | * Reads a consistent set of time-base values from Xen, into a shadow data |
| 107 | * area. Must be called at splhigh (per timecounter requirements). |
| 108 | */ |
| 109 | static void |
| 110 | get_time_values_from_xen(struct cpu_info *ci) |
| 111 | { |
| 112 | |
| 113 | volatile struct shadow *shadow = &ci_shadow[ci->ci_cpuid]; |
| 114 | |
| 115 | volatile struct vcpu_time_info *t = &ci->ci_vcpu->time; |
| 116 | uint32_t tversion; |
| 117 | |
| 118 | KASSERT(mutex_owned(&tmutex)); |
| 119 | |
| 120 | do { |
| 121 | shadow->time_version = t->version; |
| 122 | xen_rmb(); |
| 123 | shadow->tsc_stamp = t->tsc_timestamp; |
| 124 | shadow->system_time = t->system_time; |
| 125 | shadow->freq_mul = t->tsc_to_system_mul; |
| 126 | shadow->freq_shift = t->tsc_shift; |
| 127 | xen_rmb(); |
| 128 | } while ((t->version & 1) || (shadow->time_version != t->version)); |
| 129 | do { |
| 130 | tversion = HYPERVISOR_shared_info->wc_version; |
| 131 | xen_rmb(); |
| 132 | shadow->ts.tv_sec = HYPERVISOR_shared_info->wc_sec; |
| 133 | shadow->ts.tv_nsec = HYPERVISOR_shared_info->wc_nsec; |
| 134 | xen_rmb(); |
| 135 | } while ((HYPERVISOR_shared_info->wc_version & 1) || |
| 136 | (tversion != HYPERVISOR_shared_info->wc_version)); |
| 137 | } |
| 138 | |
| 139 | /* |
| 140 | * Are the values we have up to date? |
| 141 | */ |
| 142 | static inline int |
| 143 | time_values_up_to_date(struct cpu_info *ci) |
| 144 | { |
| 145 | int rv; |
| 146 | |
| 147 | volatile struct shadow *shadow = &ci_shadow[ci->ci_cpuid]; |
| 148 | |
| 149 | KASSERT(ci != NULL); |
| 150 | KASSERT(mutex_owned(&tmutex)); |
| 151 | |
| 152 | xen_rmb(); |
| 153 | rv = shadow->time_version == ci->ci_vcpu->time.version; |
| 154 | xen_rmb(); |
| 155 | |
| 156 | return rv; |
| 157 | } |
| 158 | |
| 159 | /* |
| 160 | * Xen 3 helpfully provides the CPU clock speed in the form of a multiplier |
| 161 | * and shift that can be used to convert a cycle count into nanoseconds |
| 162 | * without using an actual (slow) divide insn. |
| 163 | */ |
| 164 | static inline uint64_t |
| 165 | scale_delta(uint64_t delta, uint32_t mul_frac, int8_t shift) |
| 166 | { |
| 167 | if (shift < 0) |
| 168 | delta >>= -shift; |
| 169 | else |
| 170 | delta <<= shift; |
| 171 | |
| 172 | /* |
| 173 | * Here, we multiply a 64-bit and a 32-bit value, and take the top |
| 174 | * 64 bits of that 96-bit product. This is broken up into two |
| 175 | * 32*32=>64-bit multiplies and a 64-bit add. The casts are needed |
| 176 | * to hint to GCC that both multiplicands really are 32-bit; the |
| 177 | * generated code is still fairly bad, but not insanely so. |
| 178 | */ |
| 179 | return ((uint64_t)(uint32_t)(delta >> 32) * mul_frac) |
| 180 | + ((((uint64_t)(uint32_t)(delta & 0xFFFFFFFF)) * mul_frac) >> 32); |
| 181 | } |
| 182 | |
| 183 | /* |
| 184 | * Use cycle counter to determine ns elapsed since last Xen time update. |
| 185 | * Must be called at splhigh (per timecounter requirements). |
| 186 | */ |
| 187 | static uint64_t |
| 188 | get_tsc_offset_ns(struct cpu_info *ci) |
| 189 | { |
| 190 | uint64_t tsc_delta, offset; |
| 191 | volatile struct shadow *shadow = &ci_shadow[ci->ci_cpuid]; |
| 192 | |
| 193 | KASSERT(mutex_owned(&tmutex)); |
| 194 | tsc_delta = cpu_counter() - shadow->tsc_stamp; |
| 195 | offset = scale_delta(tsc_delta, shadow->freq_mul, |
| 196 | shadow->freq_shift); |
| 197 | |
| 198 | return offset; |
| 199 | } |
| 200 | |
| 201 | /* |
| 202 | * Returns the current system_time on given vcpu, taking care that the |
| 203 | * timestamp used is valid for the TSC measurement in question. Xen2 |
| 204 | * doesn't ensure that this won't step backwards, so we enforce |
| 205 | * monotonicity on our own in that case. Must be called at splhigh. |
| 206 | */ |
| 207 | static uint64_t |
| 208 | get_vcpu_time(struct cpu_info *ci) |
| 209 | { |
| 210 | uint64_t offset, stime; |
| 211 | volatile struct shadow *shadow = &ci_shadow[ci->ci_cpuid]; |
| 212 | |
| 213 | |
| 214 | KASSERT(mutex_owned(&tmutex)); |
| 215 | do { |
| 216 | get_time_values_from_xen(ci); |
| 217 | offset = get_tsc_offset_ns(ci); |
| 218 | stime = shadow->system_time + offset; |
| 219 | /* if the timestamp went stale before we used it, refresh */ |
| 220 | |
| 221 | } while (!time_values_up_to_date(ci)); |
| 222 | |
| 223 | return stime; |
| 224 | } |
| 225 | |
| 226 | static void |
| 227 | xen_wall_time(struct timespec *wt) |
| 228 | { |
| 229 | uint64_t nsec; |
| 230 | |
| 231 | struct cpu_info *ci = curcpu(); |
| 232 | volatile struct shadow *shadow = &ci_shadow[ci->ci_cpuid]; |
| 233 | |
| 234 | mutex_enter(&tmutex); |
| 235 | do { |
| 236 | /* |
| 237 | * Under Xen3, shadow->ts is the wall time less system time |
| 238 | * get_vcpu_time() will update shadow |
| 239 | */ |
| 240 | nsec = get_vcpu_time(ci); |
| 241 | *wt = shadow->ts; |
| 242 | nsec += wt->tv_nsec; |
| 243 | } while (!time_values_up_to_date(ci)); |
| 244 | mutex_exit(&tmutex); |
| 245 | |
| 246 | wt->tv_sec += nsec / 1000000000L; |
| 247 | wt->tv_nsec = nsec % 1000000000L; |
| 248 | } |
| 249 | |
| 250 | static int |
| 251 | xen_rtc_get(todr_chip_handle_t todr, struct timeval *tvp) |
| 252 | { |
| 253 | struct timespec wt; |
| 254 | |
| 255 | xen_wall_time(&wt); |
| 256 | tvp->tv_sec = wt.tv_sec; |
| 257 | tvp->tv_usec = wt.tv_nsec / 1000; |
| 258 | |
| 259 | return 0; |
| 260 | } |
| 261 | |
| 262 | static int |
| 263 | xen_rtc_set(todr_chip_handle_t todr, struct timeval *tvp) |
| 264 | { |
| 265 | #ifdef DOM0OPS |
| 266 | #if __XEN_INTERFACE_VERSION__ < 0x00030204 |
| 267 | dom0_op_t op; |
| 268 | #else |
| 269 | xen_platform_op_t op; |
| 270 | #endif |
| 271 | if (xendomain_is_privileged()) { |
| 272 | /* needs to set the RTC chip too */ |
| 273 | struct clock_ymdhms dt; |
| 274 | clock_secs_to_ymdhms(tvp->tv_sec, &dt); |
| 275 | rtc_set_ymdhms(NULL, &dt); |
| 276 | |
| 277 | #if __XEN_INTERFACE_VERSION__ < 0x00030204 |
| 278 | op.cmd = DOM0_SETTIME; |
| 279 | #else |
| 280 | op.cmd = XENPF_settime; |
| 281 | #endif |
| 282 | /* XXX is rtc_offset handled correctly everywhere? */ |
| 283 | op.u.settime.secs = tvp->tv_sec; |
| 284 | op.u.settime.nsecs = tvp->tv_usec * 1000; |
| 285 | mutex_enter(&tmutex); |
| 286 | op.u.settime.system_time = get_vcpu_time(curcpu()); |
| 287 | mutex_exit(&tmutex); |
| 288 | #if __XEN_INTERFACE_VERSION__ < 0x00030204 |
| 289 | return HYPERVISOR_dom0_op(&op); |
| 290 | #else |
| 291 | return HYPERVISOR_platform_op(&op); |
| 292 | #endif |
| 293 | } |
| 294 | #endif |
| 295 | |
| 296 | return 0; |
| 297 | } |
| 298 | |
| 299 | void |
| 300 | startrtclock(void) |
| 301 | { |
| 302 | static struct todr_chip_handle tch; |
| 303 | tch.todr_gettime = xen_rtc_get; |
| 304 | tch.todr_settime = xen_rtc_set; |
| 305 | tch.todr_setwen = NULL; |
| 306 | |
| 307 | todr_attach(&tch); |
| 308 | } |
| 309 | |
| 310 | /* |
| 311 | * Wait approximately `n' microseconds. |
| 312 | */ |
| 313 | void |
| 314 | xen_delay(unsigned int n) |
| 315 | { |
| 316 | struct cpu_info *ci = curcpu(); |
| 317 | volatile struct shadow *shadow = &ci_shadow[ci->ci_cpuid]; |
| 318 | |
| 319 | if (n < 500000) { |
| 320 | /* |
| 321 | * shadow->system_time is updated every hz tick, it's not |
| 322 | * precise enough for short delays. Use the CPU counter |
| 323 | * instead. We assume it's working at this point. |
| 324 | */ |
| 325 | uint64_t cc, cc2, when; |
| 326 | |
| 327 | cc = cpu_counter(); |
| 328 | when = cc + (uint64_t)n * cpu_frequency(ci) / 1000000LL; |
| 329 | if (when < cc) { |
| 330 | /* wait for counter to wrap */ |
| 331 | cc2 = cpu_counter(); |
| 332 | while (cc2 > cc) |
| 333 | cc2 = cpu_counter(); |
| 334 | } |
| 335 | cc2 = cpu_counter(); |
| 336 | while (cc2 < when) |
| 337 | cc2 = cpu_counter(); |
| 338 | |
| 339 | return; |
| 340 | } else { |
| 341 | uint64_t when; |
| 342 | |
| 343 | /* for large delays, shadow->system_time is OK */ |
| 344 | mutex_enter(&tmutex); |
| 345 | get_time_values_from_xen(ci); |
| 346 | when = shadow->system_time + n * 1000; |
| 347 | while (shadow->system_time < when) { |
| 348 | mutex_exit(&tmutex); |
| 349 | HYPERVISOR_yield(); |
| 350 | mutex_enter(&tmutex); |
| 351 | get_time_values_from_xen(ci); |
| 352 | } |
| 353 | mutex_exit(&tmutex); |
| 354 | } |
| 355 | } |
| 356 | |
| 357 | #ifdef DOM0OPS |
| 358 | /* ARGSUSED */ |
| 359 | static void |
| 360 | xen_timepush(void *arg) |
| 361 | { |
| 362 | callout_t *co = arg; |
| 363 | |
| 364 | resettodr(); |
| 365 | if (xen_timepush_ticks > 0) |
| 366 | callout_schedule(co, xen_timepush_ticks); |
| 367 | } |
| 368 | |
| 369 | /* ARGSUSED */ |
| 370 | static int |
| 371 | sysctl_xen_timepush(SYSCTLFN_ARGS) |
| 372 | { |
| 373 | int error, new_ticks; |
| 374 | struct sysctlnode node; |
| 375 | |
| 376 | new_ticks = xen_timepush_ticks; |
| 377 | node = *rnode; |
| 378 | node.sysctl_data = &new_ticks; |
| 379 | error = sysctl_lookup(SYSCTLFN_CALL(&node)); |
| 380 | if (error || newp == NULL) |
| 381 | return error; |
| 382 | |
| 383 | if (new_ticks < 0) |
| 384 | return EINVAL; |
| 385 | if (new_ticks != xen_timepush_ticks) { |
| 386 | xen_timepush_ticks = new_ticks; |
| 387 | if (new_ticks > 0) |
| 388 | callout_schedule(&xen_timepush_co, new_ticks); |
| 389 | else |
| 390 | callout_stop(&xen_timepush_co); |
| 391 | } |
| 392 | |
| 393 | return 0; |
| 394 | } |
| 395 | #endif |
| 396 | |
| 397 | /* ARGSUSED */ |
| 398 | u_int |
| 399 | xen_get_timecount(struct timecounter *tc) |
| 400 | { |
| 401 | uint64_t ns; |
| 402 | |
| 403 | struct cpu_info *ci = curcpu(); |
| 404 | |
| 405 | mutex_enter(&tmutex); |
| 406 | ns = get_vcpu_time(ci) - xen_clock_bias[ci->ci_cpuid]; |
| 407 | mutex_exit(&tmutex); |
| 408 | |
| 409 | return (u_int)ns; |
| 410 | } |
| 411 | |
| 412 | /* |
| 413 | * Needs to be called per-cpu, from the local cpu, since VIRQ_TIMER is |
| 414 | * bound per-cpu |
| 415 | */ |
| 416 | |
| 417 | static struct evcnt hardclock_called[MAXCPUS]; |
| 418 | |
| 419 | void |
| 420 | xen_initclocks(void) |
| 421 | { |
| 422 | int err __diagused; |
| 423 | static bool tcdone = false; |
| 424 | |
| 425 | struct cpu_info *ci = curcpu(); |
| 426 | volatile struct shadow *shadow = &ci_shadow[ci->ci_cpuid]; |
| 427 | |
| 428 | xen_clock_bias[ci->ci_cpuid] = 0; |
| 429 | |
| 430 | evcnt_attach_dynamic(&hardclock_called[ci->ci_cpuid], |
| 431 | EVCNT_TYPE_INTR, |
| 432 | NULL, |
| 433 | device_xname(ci->ci_dev), |
| 434 | "hardclock" ); |
| 435 | |
| 436 | #ifdef DOM0OPS |
| 437 | if (!tcdone) { /* Do this only once */ |
| 438 | callout_init(&xen_timepush_co, 0); |
| 439 | } |
| 440 | #endif |
| 441 | |
| 442 | if (!tcdone) { /* Do this only once */ |
| 443 | mutex_init(&tmutex, MUTEX_DEFAULT, IPL_CLOCK); |
| 444 | } |
| 445 | mutex_enter(&tmutex); |
| 446 | get_time_values_from_xen(ci); |
| 447 | vcpu_system_time[ci->ci_cpuid] = shadow->system_time; |
| 448 | mutex_exit(&tmutex); |
| 449 | if (!tcdone) { /* Do this only once */ |
| 450 | tc_init(&xen_timecounter); |
| 451 | } |
| 452 | |
| 453 | /* The splhigh requirements start here. */ |
| 454 | xen_resumeclocks(ci); |
| 455 | |
| 456 | /* |
| 457 | * The periodic timer looks buggy, we stop receiving events |
| 458 | * after a while. Use the one-shot timer every NS_PER_TICK |
| 459 | * and rearm it from the event handler. |
| 460 | */ |
| 461 | if (XEN_MAJOR(xen_version) > 3 || XEN_MINOR(xen_version) > 0) { |
| 462 | /* exists only on Xen 3.1 and later */ |
| 463 | err = HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, |
| 464 | ci->ci_cpuid, |
| 465 | NULL); |
| 466 | KASSERT(err == 0); |
| 467 | } |
| 468 | |
| 469 | err = HYPERVISOR_set_timer_op( |
| 470 | vcpu_system_time[ci->ci_cpuid] + NS_PER_TICK); |
| 471 | KASSERT(err == 0); |
| 472 | |
| 473 | #ifdef DOM0OPS |
| 474 | const struct sysctlnode *node = NULL; |
| 475 | |
| 476 | if (!tcdone) { /* Do this only once */ |
| 477 | |
| 478 | xen_timepush_ticks = 53 * hz + 3; /* avoid exact # of min/sec */ |
| 479 | if (xendomain_is_privileged()) { |
| 480 | sysctl_createv(NULL, 0, NULL, &node, 0, |
| 481 | CTLTYPE_NODE, "xen" , |
| 482 | SYSCTL_DESCR("Xen top level node" ), |
| 483 | NULL, 0, NULL, 0, |
| 484 | CTL_MACHDEP, CTL_CREATE, CTL_EOL); |
| 485 | if (node != NULL) { |
| 486 | sysctl_createv(NULL, 0, &node, NULL, |
| 487 | CTLFLAG_READWRITE, CTLTYPE_INT, |
| 488 | "timepush_ticks" , |
| 489 | SYSCTL_DESCR("How often to update the " |
| 490 | "hypervisor's time-of-day; 0 to disable" ), |
| 491 | sysctl_xen_timepush, 0, |
| 492 | &xen_timepush_ticks, 0, |
| 493 | CTL_CREATE, CTL_EOL); |
| 494 | } |
| 495 | callout_reset(&xen_timepush_co, xen_timepush_ticks, |
| 496 | &xen_timepush, &xen_timepush_co); |
| 497 | } |
| 498 | } |
| 499 | #endif |
| 500 | tcdone = true; |
| 501 | } |
| 502 | |
| 503 | void |
| 504 | xen_suspendclocks(struct cpu_info *ci) |
| 505 | { |
| 506 | int evtch; |
| 507 | |
| 508 | evtch = unbind_virq_from_evtch(VIRQ_TIMER); |
| 509 | KASSERT(evtch != -1); |
| 510 | |
| 511 | hypervisor_mask_event(evtch); |
| 512 | event_remove_handler(evtch, (int (*)(void *))xen_timer_handler, ci); |
| 513 | |
| 514 | aprint_verbose("Xen clock: removed event channel %d\n" , evtch); |
| 515 | } |
| 516 | |
| 517 | void |
| 518 | xen_resumeclocks(struct cpu_info *ci) |
| 519 | { |
| 520 | int evtch; |
| 521 | |
| 522 | evtch = bind_virq_to_evtch(VIRQ_TIMER); |
| 523 | KASSERT(evtch != -1); |
| 524 | |
| 525 | event_set_handler(evtch, (int (*)(void *))xen_timer_handler, |
| 526 | ci, IPL_CLOCK, "clock" ); |
| 527 | hypervisor_enable_event(evtch); |
| 528 | |
| 529 | aprint_verbose("Xen clock: using event channel %d\n" , evtch); |
| 530 | } |
| 531 | |
| 532 | /* ARGSUSED */ |
| 533 | static int |
| 534 | xen_timer_handler(void *arg, struct intrframe *regs) |
| 535 | { |
| 536 | int64_t delta; |
| 537 | struct cpu_info *ci = curcpu(); |
| 538 | KASSERT(arg == ci); |
| 539 | int err; |
| 540 | again: |
| 541 | mutex_enter(&tmutex); |
| 542 | delta = (int64_t)(get_vcpu_time(ci) - vcpu_system_time[ci->ci_cpuid]); |
| 543 | mutex_exit(&tmutex); |
| 544 | |
| 545 | /* Several ticks may have passed without our being run; catch up. */ |
| 546 | while (delta >= (int64_t)NS_PER_TICK) { |
| 547 | mutex_enter(&tmutex); |
| 548 | vcpu_system_time[ci->ci_cpuid] += NS_PER_TICK; |
| 549 | xen_clock_bias[ci->ci_cpuid] = (delta -= NS_PER_TICK); |
| 550 | mutex_exit(&tmutex); |
| 551 | hardclock((struct clockframe *)regs); |
| 552 | hardclock_called[ci->ci_cpuid].ev_count++; |
| 553 | } |
| 554 | |
| 555 | /* |
| 556 | * rearm the timer. If it fails it's probably because the date |
| 557 | * is in the past, update our local time and try again. |
| 558 | */ |
| 559 | err = HYPERVISOR_set_timer_op( |
| 560 | vcpu_system_time[ci->ci_cpuid] + NS_PER_TICK); |
| 561 | if (err) |
| 562 | goto again; |
| 563 | |
| 564 | if (xen_clock_bias[ci->ci_cpuid]) { |
| 565 | mutex_enter(&tmutex); |
| 566 | xen_clock_bias[ci->ci_cpuid] = 0; |
| 567 | mutex_exit(&tmutex); |
| 568 | } |
| 569 | |
| 570 | return 0; |
| 571 | } |
| 572 | |
| 573 | void |
| 574 | setstatclockrate(int arg) |
| 575 | { |
| 576 | } |
| 577 | |
| 578 | void |
| 579 | idle_block(void) |
| 580 | { |
| 581 | KASSERT(curcpu()->ci_ipending == 0); |
| 582 | HYPERVISOR_block(); |
| 583 | } |
| 584 | |