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1/*
2 * KVM paravirt_ops implementation
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
17 *
18 * Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
19 * Copyright IBM Corporation, 2007
20 * Authors: Anthony Liguori <aliguori@us.ibm.com>
21 */
22
23#include <linux/context_tracking.h>
24#include <linux/module.h>
25#include <linux/kernel.h>
26#include <linux/kvm_para.h>
27#include <linux/cpu.h>
28#include <linux/mm.h>
29#include <linux/highmem.h>
30#include <linux/hardirq.h>
31#include <linux/notifier.h>
32#include <linux/reboot.h>
33#include <linux/hash.h>
34#include <linux/sched.h>
35#include <linux/slab.h>
36#include <linux/kprobes.h>
37#include <linux/debugfs.h>
38#include <linux/nmi.h>
39#include <linux/swait.h>
40#include <asm/timer.h>
41#include <asm/cpu.h>
42#include <asm/traps.h>
43#include <asm/desc.h>
44#include <asm/tlbflush.h>
45#include <asm/idle.h>
46#include <asm/apic.h>
47#include <asm/apicdef.h>
48#include <asm/hypervisor.h>
49#include <asm/kvm_guest.h>
50
51static int kvmapf = 1;
52
53static int parse_no_kvmapf(char *arg)
54{
55 kvmapf = 0;
56 return 0;
57}
58
59early_param("no-kvmapf", parse_no_kvmapf);
60
61static int steal_acc = 1;
62static int parse_no_stealacc(char *arg)
63{
64 steal_acc = 0;
65 return 0;
66}
67
68early_param("no-steal-acc", parse_no_stealacc);
69
70static int kvmclock_vsyscall = 1;
71static int parse_no_kvmclock_vsyscall(char *arg)
72{
73 kvmclock_vsyscall = 0;
74 return 0;
75}
76
77early_param("no-kvmclock-vsyscall", parse_no_kvmclock_vsyscall);
78
79static DEFINE_PER_CPU(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);
80static DEFINE_PER_CPU(struct kvm_steal_time, steal_time) __aligned(64);
81static int has_steal_clock = 0;
82
83/*
84 * No need for any "IO delay" on KVM
85 */
86static void kvm_io_delay(void)
87{
88}
89
90#define KVM_TASK_SLEEP_HASHBITS 8
91#define KVM_TASK_SLEEP_HASHSIZE (1<<KVM_TASK_SLEEP_HASHBITS)
92
93struct kvm_task_sleep_node {
94 struct hlist_node link;
95 struct swait_queue_head wq;
96 u32 token;
97 int cpu;
98 bool halted;
99};
100
101static struct kvm_task_sleep_head {
102 raw_spinlock_t lock;
103 struct hlist_head list;
104} async_pf_sleepers[KVM_TASK_SLEEP_HASHSIZE];
105
106static struct kvm_task_sleep_node *_find_apf_task(struct kvm_task_sleep_head *b,
107 u32 token)
108{
109 struct hlist_node *p;
110
111 hlist_for_each(p, &b->list) {
112 struct kvm_task_sleep_node *n =
113 hlist_entry(p, typeof(*n), link);
114 if (n->token == token)
115 return n;
116 }
117
118 return NULL;
119}
120
121void kvm_async_pf_task_wait(u32 token)
122{
123 u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
124 struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
125 struct kvm_task_sleep_node n, *e;
126 DECLARE_SWAITQUEUE(wait);
127
128 rcu_irq_enter();
129
130 raw_spin_lock(&b->lock);
131 e = _find_apf_task(b, token);
132 if (e) {
133 /* dummy entry exist -> wake up was delivered ahead of PF */
134 hlist_del(&e->link);
135 kfree(e);
136 raw_spin_unlock(&b->lock);
137
138 rcu_irq_exit();
139 return;
140 }
141
142 n.token = token;
143 n.cpu = smp_processor_id();
144 n.halted = is_idle_task(current) || preempt_count() > 1;
145 init_swait_queue_head(&n.wq);
146 hlist_add_head(&n.link, &b->list);
147 raw_spin_unlock(&b->lock);
148
149 for (;;) {
150 if (!n.halted)
151 prepare_to_swait(&n.wq, &wait, TASK_UNINTERRUPTIBLE);
152 if (hlist_unhashed(&n.link))
153 break;
154
155 if (!n.halted) {
156 local_irq_enable();
157 schedule();
158 local_irq_disable();
159 } else {
160 /*
161 * We cannot reschedule. So halt.
162 */
163 rcu_irq_exit();
164 native_safe_halt();
165 rcu_irq_enter();
166 local_irq_disable();
167 }
168 }
169 if (!n.halted)
170 finish_swait(&n.wq, &wait);
171
172 rcu_irq_exit();
173 return;
174}
175EXPORT_SYMBOL_GPL(kvm_async_pf_task_wait);
176
177static void apf_task_wake_one(struct kvm_task_sleep_node *n)
178{
179 hlist_del_init(&n->link);
180 if (n->halted)
181 smp_send_reschedule(n->cpu);
182 else if (swait_active(&n->wq))
183 swake_up(&n->wq);
184}
185
186static void apf_task_wake_all(void)
187{
188 int i;
189
190 for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) {
191 struct hlist_node *p, *next;
192 struct kvm_task_sleep_head *b = &async_pf_sleepers[i];
193 raw_spin_lock(&b->lock);
194 hlist_for_each_safe(p, next, &b->list) {
195 struct kvm_task_sleep_node *n =
196 hlist_entry(p, typeof(*n), link);
197 if (n->cpu == smp_processor_id())
198 apf_task_wake_one(n);
199 }
200 raw_spin_unlock(&b->lock);
201 }
202}
203
204void kvm_async_pf_task_wake(u32 token)
205{
206 u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
207 struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
208 struct kvm_task_sleep_node *n;
209
210 if (token == ~0) {
211 apf_task_wake_all();
212 return;
213 }
214
215again:
216 raw_spin_lock(&b->lock);
217 n = _find_apf_task(b, token);
218 if (!n) {
219 /*
220 * async PF was not yet handled.
221 * Add dummy entry for the token.
222 */
223 n = kzalloc(sizeof(*n), GFP_ATOMIC);
224 if (!n) {
225 /*
226 * Allocation failed! Busy wait while other cpu
227 * handles async PF.
228 */
229 raw_spin_unlock(&b->lock);
230 cpu_relax();
231 goto again;
232 }
233 n->token = token;
234 n->cpu = smp_processor_id();
235 init_swait_queue_head(&n->wq);
236 hlist_add_head(&n->link, &b->list);
237 } else
238 apf_task_wake_one(n);
239 raw_spin_unlock(&b->lock);
240 return;
241}
242EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake);
243
244u32 kvm_read_and_reset_pf_reason(void)
245{
246 u32 reason = 0;
247
248 if (__this_cpu_read(apf_reason.enabled)) {
249 reason = __this_cpu_read(apf_reason.reason);
250 __this_cpu_write(apf_reason.reason, 0);
251 }
252
253 return reason;
254}
255EXPORT_SYMBOL_GPL(kvm_read_and_reset_pf_reason);
256NOKPROBE_SYMBOL(kvm_read_and_reset_pf_reason);
257
258dotraplinkage void
259do_async_page_fault(struct pt_regs *regs, unsigned long error_code)
260{
261 enum ctx_state prev_state;
262
263 switch (kvm_read_and_reset_pf_reason()) {
264 default:
265 trace_do_page_fault(regs, error_code);
266 break;
267 case KVM_PV_REASON_PAGE_NOT_PRESENT:
268 /* page is swapped out by the host. */
269 prev_state = exception_enter();
270 exit_idle();
271 kvm_async_pf_task_wait((u32)read_cr2());
272 exception_exit(prev_state);
273 break;
274 case KVM_PV_REASON_PAGE_READY:
275 rcu_irq_enter();
276 exit_idle();
277 kvm_async_pf_task_wake((u32)read_cr2());
278 rcu_irq_exit();
279 break;
280 }
281}
282NOKPROBE_SYMBOL(do_async_page_fault);
283
284static void __init paravirt_ops_setup(void)
285{
286 pv_info.name = "KVM";
287
288 /*
289 * KVM isn't paravirt in the sense of paravirt_enabled. A KVM
290 * guest kernel works like a bare metal kernel with additional
291 * features, and paravirt_enabled is about features that are
292 * missing.
293 */
294 pv_info.paravirt_enabled = 0;
295
296 if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
297 pv_cpu_ops.io_delay = kvm_io_delay;
298
299#ifdef CONFIG_X86_IO_APIC
300 no_timer_check = 1;
301#endif
302}
303
304static void kvm_register_steal_time(void)
305{
306 int cpu = smp_processor_id();
307 struct kvm_steal_time *st = &per_cpu(steal_time, cpu);
308
309 if (!has_steal_clock)
310 return;
311
312 memset(st, 0, sizeof(*st));
313
314 wrmsrl(MSR_KVM_STEAL_TIME, (slow_virt_to_phys(st) | KVM_MSR_ENABLED));
315 pr_info("kvm-stealtime: cpu %d, msr %llx\n",
316 cpu, (unsigned long long) slow_virt_to_phys(st));
317}
318
319static DEFINE_PER_CPU(unsigned long, kvm_apic_eoi) = KVM_PV_EOI_DISABLED;
320
321static void kvm_guest_apic_eoi_write(u32 reg, u32 val)
322{
323 /**
324 * This relies on __test_and_clear_bit to modify the memory
325 * in a way that is atomic with respect to the local CPU.
326 * The hypervisor only accesses this memory from the local CPU so
327 * there's no need for lock or memory barriers.
328 * An optimization barrier is implied in apic write.
329 */
330 if (__test_and_clear_bit(KVM_PV_EOI_BIT, this_cpu_ptr(&kvm_apic_eoi)))
331 return;
332 apic_write(APIC_EOI, APIC_EOI_ACK);
333}
334
335static void kvm_guest_cpu_init(void)
336{
337 if (!kvm_para_available())
338 return;
339
340 if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf) {
341 u64 pa = slow_virt_to_phys(this_cpu_ptr(&apf_reason));
342
343#ifdef CONFIG_PREEMPT
344 pa |= KVM_ASYNC_PF_SEND_ALWAYS;
345#endif
346 wrmsrl(MSR_KVM_ASYNC_PF_EN, pa | KVM_ASYNC_PF_ENABLED);
347 __this_cpu_write(apf_reason.enabled, 1);
348 printk(KERN_INFO"KVM setup async PF for cpu %d\n",
349 smp_processor_id());
350 }
351
352 if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) {
353 unsigned long pa;
354 /* Size alignment is implied but just to make it explicit. */
355 BUILD_BUG_ON(__alignof__(kvm_apic_eoi) < 4);
356 __this_cpu_write(kvm_apic_eoi, 0);
357 pa = slow_virt_to_phys(this_cpu_ptr(&kvm_apic_eoi))
358 | KVM_MSR_ENABLED;
359 wrmsrl(MSR_KVM_PV_EOI_EN, pa);
360 }
361
362 if (has_steal_clock)
363 kvm_register_steal_time();
364}
365
366static void kvm_pv_disable_apf(void)
367{
368 if (!__this_cpu_read(apf_reason.enabled))
369 return;
370
371 wrmsrl(MSR_KVM_ASYNC_PF_EN, 0);
372 __this_cpu_write(apf_reason.enabled, 0);
373
374 printk(KERN_INFO"Unregister pv shared memory for cpu %d\n",
375 smp_processor_id());
376}
377
378static void kvm_pv_guest_cpu_reboot(void *unused)
379{
380 /*
381 * We disable PV EOI before we load a new kernel by kexec,
382 * since MSR_KVM_PV_EOI_EN stores a pointer into old kernel's memory.
383 * New kernel can re-enable when it boots.
384 */
385 if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
386 wrmsrl(MSR_KVM_PV_EOI_EN, 0);
387 kvm_pv_disable_apf();
388 kvm_disable_steal_time();
389}
390
391static int kvm_pv_reboot_notify(struct notifier_block *nb,
392 unsigned long code, void *unused)
393{
394 if (code == SYS_RESTART)
395 on_each_cpu(kvm_pv_guest_cpu_reboot, NULL, 1);
396 return NOTIFY_DONE;
397}
398
399static struct notifier_block kvm_pv_reboot_nb = {
400 .notifier_call = kvm_pv_reboot_notify,
401};
402
403static u64 kvm_steal_clock(int cpu)
404{
405 u64 steal;
406 struct kvm_steal_time *src;
407 int version;
408
409 src = &per_cpu(steal_time, cpu);
410 do {
411 version = src->version;
412 rmb();
413 steal = src->steal;
414 rmb();
415 } while ((version & 1) || (version != src->version));
416
417 return steal;
418}
419
420void kvm_disable_steal_time(void)
421{
422 if (!has_steal_clock)
423 return;
424
425 wrmsr(MSR_KVM_STEAL_TIME, 0, 0);
426}
427
428#ifdef CONFIG_SMP
429static void __init kvm_smp_prepare_boot_cpu(void)
430{
431 kvm_guest_cpu_init();
432 native_smp_prepare_boot_cpu();
433 kvm_spinlock_init();
434}
435
436static void kvm_guest_cpu_online(void *dummy)
437{
438 kvm_guest_cpu_init();
439}
440
441static void kvm_guest_cpu_offline(void *dummy)
442{
443 kvm_disable_steal_time();
444 if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
445 wrmsrl(MSR_KVM_PV_EOI_EN, 0);
446 kvm_pv_disable_apf();
447 apf_task_wake_all();
448}
449
450static int kvm_cpu_notify(struct notifier_block *self, unsigned long action,
451 void *hcpu)
452{
453 int cpu = (unsigned long)hcpu;
454 switch (action) {
455 case CPU_ONLINE:
456 case CPU_DOWN_FAILED:
457 case CPU_ONLINE_FROZEN:
458 smp_call_function_single(cpu, kvm_guest_cpu_online, NULL, 0);
459 break;
460 case CPU_DOWN_PREPARE:
461 case CPU_DOWN_PREPARE_FROZEN:
462 smp_call_function_single(cpu, kvm_guest_cpu_offline, NULL, 1);
463 break;
464 default:
465 break;
466 }
467 return NOTIFY_OK;
468}
469
470static struct notifier_block kvm_cpu_notifier = {
471 .notifier_call = kvm_cpu_notify,
472};
473#endif
474
475static void __init kvm_apf_trap_init(void)
476{
477 set_intr_gate(14, async_page_fault);
478}
479
480void __init kvm_guest_init(void)
481{
482 int i;
483
484 if (!kvm_para_available())
485 return;
486
487 paravirt_ops_setup();
488 register_reboot_notifier(&kvm_pv_reboot_nb);
489 for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++)
490 raw_spin_lock_init(&async_pf_sleepers[i].lock);
491 if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF))
492 x86_init.irqs.trap_init = kvm_apf_trap_init;
493
494 if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
495 has_steal_clock = 1;
496 pv_time_ops.steal_clock = kvm_steal_clock;
497 }
498
499 if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
500 apic_set_eoi_write(kvm_guest_apic_eoi_write);
501
502 if (kvmclock_vsyscall)
503 kvm_setup_vsyscall_timeinfo();
504
505#ifdef CONFIG_SMP
506 smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
507 register_cpu_notifier(&kvm_cpu_notifier);
508#else
509 kvm_guest_cpu_init();
510#endif
511
512 /*
513 * Hard lockup detection is enabled by default. Disable it, as guests
514 * can get false positives too easily, for example if the host is
515 * overcommitted.
516 */
517 hardlockup_detector_disable();
518}
519
520static noinline uint32_t __kvm_cpuid_base(void)
521{
522 if (boot_cpu_data.cpuid_level < 0)
523 return 0; /* So we don't blow up on old processors */
524
525 if (cpu_has_hypervisor)
526 return hypervisor_cpuid_base("KVMKVMKVM\0\0\0", 0);
527
528 return 0;
529}
530
531static inline uint32_t kvm_cpuid_base(void)
532{
533 static int kvm_cpuid_base = -1;
534
535 if (kvm_cpuid_base == -1)
536 kvm_cpuid_base = __kvm_cpuid_base();
537
538 return kvm_cpuid_base;
539}
540
541bool kvm_para_available(void)
542{
543 return kvm_cpuid_base() != 0;
544}
545EXPORT_SYMBOL_GPL(kvm_para_available);
546
547unsigned int kvm_arch_para_features(void)
548{
549 return cpuid_eax(kvm_cpuid_base() | KVM_CPUID_FEATURES);
550}
551
552static uint32_t __init kvm_detect(void)
553{
554 return kvm_cpuid_base();
555}
556
557const struct hypervisor_x86 x86_hyper_kvm __refconst = {
558 .name = "KVM",
559 .detect = kvm_detect,
560 .x2apic_available = kvm_para_available,
561};
562EXPORT_SYMBOL_GPL(x86_hyper_kvm);
563
564static __init int activate_jump_labels(void)
565{
566 if (has_steal_clock) {
567 static_key_slow_inc(¶virt_steal_enabled);
568 if (steal_acc)
569 static_key_slow_inc(¶virt_steal_rq_enabled);
570 }
571
572 return 0;
573}
574arch_initcall(activate_jump_labels);
575
576#ifdef CONFIG_PARAVIRT_SPINLOCKS
577
578/* Kick a cpu by its apicid. Used to wake up a halted vcpu */
579static void kvm_kick_cpu(int cpu)
580{
581 int apicid;
582 unsigned long flags = 0;
583
584 apicid = per_cpu(x86_cpu_to_apicid, cpu);
585 kvm_hypercall2(KVM_HC_KICK_CPU, flags, apicid);
586}
587
588
589#ifdef CONFIG_QUEUED_SPINLOCKS
590
591#include <asm/qspinlock.h>
592
593static void kvm_wait(u8 *ptr, u8 val)
594{
595 unsigned long flags;
596
597 if (in_nmi())
598 return;
599
600 local_irq_save(flags);
601
602 if (READ_ONCE(*ptr) != val)
603 goto out;
604
605 /*
606 * halt until it's our turn and kicked. Note that we do safe halt
607 * for irq enabled case to avoid hang when lock info is overwritten
608 * in irq spinlock slowpath and no spurious interrupt occur to save us.
609 */
610 if (arch_irqs_disabled_flags(flags))
611 halt();
612 else
613 safe_halt();
614
615out:
616 local_irq_restore(flags);
617}
618
619#else /* !CONFIG_QUEUED_SPINLOCKS */
620
621enum kvm_contention_stat {
622 TAKEN_SLOW,
623 TAKEN_SLOW_PICKUP,
624 RELEASED_SLOW,
625 RELEASED_SLOW_KICKED,
626 NR_CONTENTION_STATS
627};
628
629#ifdef CONFIG_KVM_DEBUG_FS
630#define HISTO_BUCKETS 30
631
632static struct kvm_spinlock_stats
633{
634 u32 contention_stats[NR_CONTENTION_STATS];
635 u32 histo_spin_blocked[HISTO_BUCKETS+1];
636 u64 time_blocked;
637} spinlock_stats;
638
639static u8 zero_stats;
640
641static inline void check_zero(void)
642{
643 u8 ret;
644 u8 old;
645
646 old = READ_ONCE(zero_stats);
647 if (unlikely(old)) {
648 ret = cmpxchg(&zero_stats, old, 0);
649 /* This ensures only one fellow resets the stat */
650 if (ret == old)
651 memset(&spinlock_stats, 0, sizeof(spinlock_stats));
652 }
653}
654
655static inline void add_stats(enum kvm_contention_stat var, u32 val)
656{
657 check_zero();
658 spinlock_stats.contention_stats[var] += val;
659}
660
661
662static inline u64 spin_time_start(void)
663{
664 return sched_clock();
665}
666
667static void __spin_time_accum(u64 delta, u32 *array)
668{
669 unsigned index;
670
671 index = ilog2(delta);
672 check_zero();
673
674 if (index < HISTO_BUCKETS)
675 array[index]++;
676 else
677 array[HISTO_BUCKETS]++;
678}
679
680static inline void spin_time_accum_blocked(u64 start)
681{
682 u32 delta;
683
684 delta = sched_clock() - start;
685 __spin_time_accum(delta, spinlock_stats.histo_spin_blocked);
686 spinlock_stats.time_blocked += delta;
687}
688
689static struct dentry *d_spin_debug;
690static struct dentry *d_kvm_debug;
691
692static struct dentry *kvm_init_debugfs(void)
693{
694 d_kvm_debug = debugfs_create_dir("kvm-guest", NULL);
695 if (!d_kvm_debug)
696 printk(KERN_WARNING "Could not create 'kvm' debugfs directory\n");
697
698 return d_kvm_debug;
699}
700
701static int __init kvm_spinlock_debugfs(void)
702{
703 struct dentry *d_kvm;
704
705 d_kvm = kvm_init_debugfs();
706 if (d_kvm == NULL)
707 return -ENOMEM;
708
709 d_spin_debug = debugfs_create_dir("spinlocks", d_kvm);
710
711 debugfs_create_u8("zero_stats", 0644, d_spin_debug, &zero_stats);
712
713 debugfs_create_u32("taken_slow", 0444, d_spin_debug,
714 &spinlock_stats.contention_stats[TAKEN_SLOW]);
715 debugfs_create_u32("taken_slow_pickup", 0444, d_spin_debug,
716 &spinlock_stats.contention_stats[TAKEN_SLOW_PICKUP]);
717
718 debugfs_create_u32("released_slow", 0444, d_spin_debug,
719 &spinlock_stats.contention_stats[RELEASED_SLOW]);
720 debugfs_create_u32("released_slow_kicked", 0444, d_spin_debug,
721 &spinlock_stats.contention_stats[RELEASED_SLOW_KICKED]);
722
723 debugfs_create_u64("time_blocked", 0444, d_spin_debug,
724 &spinlock_stats.time_blocked);
725
726 debugfs_create_u32_array("histo_blocked", 0444, d_spin_debug,
727 spinlock_stats.histo_spin_blocked, HISTO_BUCKETS + 1);
728
729 return 0;
730}
731fs_initcall(kvm_spinlock_debugfs);
732#else /* !CONFIG_KVM_DEBUG_FS */
733static inline void add_stats(enum kvm_contention_stat var, u32 val)
734{
735}
736
737static inline u64 spin_time_start(void)
738{
739 return 0;
740}
741
742static inline void spin_time_accum_blocked(u64 start)
743{
744}
745#endif /* CONFIG_KVM_DEBUG_FS */
746
747struct kvm_lock_waiting {
748 struct arch_spinlock *lock;
749 __ticket_t want;
750};
751
752/* cpus 'waiting' on a spinlock to become available */
753static cpumask_t waiting_cpus;
754
755/* Track spinlock on which a cpu is waiting */
756static DEFINE_PER_CPU(struct kvm_lock_waiting, klock_waiting);
757
758__visible void kvm_lock_spinning(struct arch_spinlock *lock, __ticket_t want)
759{
760 struct kvm_lock_waiting *w;
761 int cpu;
762 u64 start;
763 unsigned long flags;
764 __ticket_t head;
765
766 if (in_nmi())
767 return;
768
769 w = this_cpu_ptr(&klock_waiting);
770 cpu = smp_processor_id();
771 start = spin_time_start();
772
773 /*
774 * Make sure an interrupt handler can't upset things in a
775 * partially setup state.
776 */
777 local_irq_save(flags);
778
779 /*
780 * The ordering protocol on this is that the "lock" pointer
781 * may only be set non-NULL if the "want" ticket is correct.
782 * If we're updating "want", we must first clear "lock".
783 */
784 w->lock = NULL;
785 smp_wmb();
786 w->want = want;
787 smp_wmb();
788 w->lock = lock;
789
790 add_stats(TAKEN_SLOW, 1);
791
792 /*
793 * This uses set_bit, which is atomic but we should not rely on its
794 * reordering gurantees. So barrier is needed after this call.
795 */
796 cpumask_set_cpu(cpu, &waiting_cpus);
797
798 barrier();
799
800 /*
801 * Mark entry to slowpath before doing the pickup test to make
802 * sure we don't deadlock with an unlocker.
803 */
804 __ticket_enter_slowpath(lock);
805
806 /* make sure enter_slowpath, which is atomic does not cross the read */
807 smp_mb__after_atomic();
808
809 /*
810 * check again make sure it didn't become free while
811 * we weren't looking.
812 */
813 head = READ_ONCE(lock->tickets.head);
814 if (__tickets_equal(head, want)) {
815 add_stats(TAKEN_SLOW_PICKUP, 1);
816 goto out;
817 }
818
819 /*
820 * halt until it's our turn and kicked. Note that we do safe halt
821 * for irq enabled case to avoid hang when lock info is overwritten
822 * in irq spinlock slowpath and no spurious interrupt occur to save us.
823 */
824 if (arch_irqs_disabled_flags(flags))
825 halt();
826 else
827 safe_halt();
828
829out:
830 cpumask_clear_cpu(cpu, &waiting_cpus);
831 w->lock = NULL;
832 local_irq_restore(flags);
833 spin_time_accum_blocked(start);
834}
835PV_CALLEE_SAVE_REGS_THUNK(kvm_lock_spinning);
836
837/* Kick vcpu waiting on @lock->head to reach value @ticket */
838static void kvm_unlock_kick(struct arch_spinlock *lock, __ticket_t ticket)
839{
840 int cpu;
841
842 add_stats(RELEASED_SLOW, 1);
843 for_each_cpu(cpu, &waiting_cpus) {
844 const struct kvm_lock_waiting *w = &per_cpu(klock_waiting, cpu);
845 if (READ_ONCE(w->lock) == lock &&
846 READ_ONCE(w->want) == ticket) {
847 add_stats(RELEASED_SLOW_KICKED, 1);
848 kvm_kick_cpu(cpu);
849 break;
850 }
851 }
852}
853
854#endif /* !CONFIG_QUEUED_SPINLOCKS */
855
856/*
857 * Setup pv_lock_ops to exploit KVM_FEATURE_PV_UNHALT if present.
858 */
859void __init kvm_spinlock_init(void)
860{
861 if (!kvm_para_available())
862 return;
863 /* Does host kernel support KVM_FEATURE_PV_UNHALT? */
864 if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT))
865 return;
866
867#ifdef CONFIG_QUEUED_SPINLOCKS
868 __pv_init_lock_hash();
869 pv_lock_ops.queued_spin_lock_slowpath = __pv_queued_spin_lock_slowpath;
870 pv_lock_ops.queued_spin_unlock = PV_CALLEE_SAVE(__pv_queued_spin_unlock);
871 pv_lock_ops.wait = kvm_wait;
872 pv_lock_ops.kick = kvm_kick_cpu;
873#else /* !CONFIG_QUEUED_SPINLOCKS */
874 pv_lock_ops.lock_spinning = PV_CALLEE_SAVE(kvm_lock_spinning);
875 pv_lock_ops.unlock_kick = kvm_unlock_kick;
876#endif
877}
878
879static __init int kvm_spinlock_init_jump(void)
880{
881 if (!kvm_para_available())
882 return 0;
883 if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT))
884 return 0;
885
886 static_key_slow_inc(¶virt_ticketlocks_enabled);
887 printk(KERN_INFO "KVM setup paravirtual spinlock\n");
888
889 return 0;
890}
891early_initcall(kvm_spinlock_init_jump);
892
893#endif /* CONFIG_PARAVIRT_SPINLOCKS */
1/*
2 * KVM paravirt_ops implementation
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
17 *
18 * Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
19 * Copyright IBM Corporation, 2007
20 * Authors: Anthony Liguori <aliguori@us.ibm.com>
21 */
22
23#include <linux/module.h>
24#include <linux/kernel.h>
25#include <linux/kvm_para.h>
26#include <linux/cpu.h>
27#include <linux/mm.h>
28#include <linux/highmem.h>
29#include <linux/hardirq.h>
30#include <linux/notifier.h>
31#include <linux/reboot.h>
32#include <linux/hash.h>
33#include <linux/sched.h>
34#include <linux/slab.h>
35#include <linux/kprobes.h>
36#include <asm/timer.h>
37#include <asm/cpu.h>
38#include <asm/traps.h>
39#include <asm/desc.h>
40#include <asm/tlbflush.h>
41
42#define MMU_QUEUE_SIZE 1024
43
44static int kvmapf = 1;
45
46static int parse_no_kvmapf(char *arg)
47{
48 kvmapf = 0;
49 return 0;
50}
51
52early_param("no-kvmapf", parse_no_kvmapf);
53
54static int steal_acc = 1;
55static int parse_no_stealacc(char *arg)
56{
57 steal_acc = 0;
58 return 0;
59}
60
61early_param("no-steal-acc", parse_no_stealacc);
62
63struct kvm_para_state {
64 u8 mmu_queue[MMU_QUEUE_SIZE];
65 int mmu_queue_len;
66};
67
68static DEFINE_PER_CPU(struct kvm_para_state, para_state);
69static DEFINE_PER_CPU(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);
70static DEFINE_PER_CPU(struct kvm_steal_time, steal_time) __aligned(64);
71static int has_steal_clock = 0;
72
73static struct kvm_para_state *kvm_para_state(void)
74{
75 return &per_cpu(para_state, raw_smp_processor_id());
76}
77
78/*
79 * No need for any "IO delay" on KVM
80 */
81static void kvm_io_delay(void)
82{
83}
84
85#define KVM_TASK_SLEEP_HASHBITS 8
86#define KVM_TASK_SLEEP_HASHSIZE (1<<KVM_TASK_SLEEP_HASHBITS)
87
88struct kvm_task_sleep_node {
89 struct hlist_node link;
90 wait_queue_head_t wq;
91 u32 token;
92 int cpu;
93 bool halted;
94 struct mm_struct *mm;
95};
96
97static struct kvm_task_sleep_head {
98 spinlock_t lock;
99 struct hlist_head list;
100} async_pf_sleepers[KVM_TASK_SLEEP_HASHSIZE];
101
102static struct kvm_task_sleep_node *_find_apf_task(struct kvm_task_sleep_head *b,
103 u32 token)
104{
105 struct hlist_node *p;
106
107 hlist_for_each(p, &b->list) {
108 struct kvm_task_sleep_node *n =
109 hlist_entry(p, typeof(*n), link);
110 if (n->token == token)
111 return n;
112 }
113
114 return NULL;
115}
116
117void kvm_async_pf_task_wait(u32 token)
118{
119 u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
120 struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
121 struct kvm_task_sleep_node n, *e;
122 DEFINE_WAIT(wait);
123 int cpu, idle;
124
125 cpu = get_cpu();
126 idle = idle_cpu(cpu);
127 put_cpu();
128
129 spin_lock(&b->lock);
130 e = _find_apf_task(b, token);
131 if (e) {
132 /* dummy entry exist -> wake up was delivered ahead of PF */
133 hlist_del(&e->link);
134 kfree(e);
135 spin_unlock(&b->lock);
136 return;
137 }
138
139 n.token = token;
140 n.cpu = smp_processor_id();
141 n.mm = current->active_mm;
142 n.halted = idle || preempt_count() > 1;
143 atomic_inc(&n.mm->mm_count);
144 init_waitqueue_head(&n.wq);
145 hlist_add_head(&n.link, &b->list);
146 spin_unlock(&b->lock);
147
148 for (;;) {
149 if (!n.halted)
150 prepare_to_wait(&n.wq, &wait, TASK_UNINTERRUPTIBLE);
151 if (hlist_unhashed(&n.link))
152 break;
153
154 if (!n.halted) {
155 local_irq_enable();
156 schedule();
157 local_irq_disable();
158 } else {
159 /*
160 * We cannot reschedule. So halt.
161 */
162 native_safe_halt();
163 local_irq_disable();
164 }
165 }
166 if (!n.halted)
167 finish_wait(&n.wq, &wait);
168
169 return;
170}
171EXPORT_SYMBOL_GPL(kvm_async_pf_task_wait);
172
173static void apf_task_wake_one(struct kvm_task_sleep_node *n)
174{
175 hlist_del_init(&n->link);
176 if (!n->mm)
177 return;
178 mmdrop(n->mm);
179 if (n->halted)
180 smp_send_reschedule(n->cpu);
181 else if (waitqueue_active(&n->wq))
182 wake_up(&n->wq);
183}
184
185static void apf_task_wake_all(void)
186{
187 int i;
188
189 for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) {
190 struct hlist_node *p, *next;
191 struct kvm_task_sleep_head *b = &async_pf_sleepers[i];
192 spin_lock(&b->lock);
193 hlist_for_each_safe(p, next, &b->list) {
194 struct kvm_task_sleep_node *n =
195 hlist_entry(p, typeof(*n), link);
196 if (n->cpu == smp_processor_id())
197 apf_task_wake_one(n);
198 }
199 spin_unlock(&b->lock);
200 }
201}
202
203void kvm_async_pf_task_wake(u32 token)
204{
205 u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
206 struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
207 struct kvm_task_sleep_node *n;
208
209 if (token == ~0) {
210 apf_task_wake_all();
211 return;
212 }
213
214again:
215 spin_lock(&b->lock);
216 n = _find_apf_task(b, token);
217 if (!n) {
218 /*
219 * async PF was not yet handled.
220 * Add dummy entry for the token.
221 */
222 n = kmalloc(sizeof(*n), GFP_ATOMIC);
223 if (!n) {
224 /*
225 * Allocation failed! Busy wait while other cpu
226 * handles async PF.
227 */
228 spin_unlock(&b->lock);
229 cpu_relax();
230 goto again;
231 }
232 n->token = token;
233 n->cpu = smp_processor_id();
234 n->mm = NULL;
235 init_waitqueue_head(&n->wq);
236 hlist_add_head(&n->link, &b->list);
237 } else
238 apf_task_wake_one(n);
239 spin_unlock(&b->lock);
240 return;
241}
242EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake);
243
244u32 kvm_read_and_reset_pf_reason(void)
245{
246 u32 reason = 0;
247
248 if (__get_cpu_var(apf_reason).enabled) {
249 reason = __get_cpu_var(apf_reason).reason;
250 __get_cpu_var(apf_reason).reason = 0;
251 }
252
253 return reason;
254}
255EXPORT_SYMBOL_GPL(kvm_read_and_reset_pf_reason);
256
257dotraplinkage void __kprobes
258do_async_page_fault(struct pt_regs *regs, unsigned long error_code)
259{
260 switch (kvm_read_and_reset_pf_reason()) {
261 default:
262 do_page_fault(regs, error_code);
263 break;
264 case KVM_PV_REASON_PAGE_NOT_PRESENT:
265 /* page is swapped out by the host. */
266 kvm_async_pf_task_wait((u32)read_cr2());
267 break;
268 case KVM_PV_REASON_PAGE_READY:
269 kvm_async_pf_task_wake((u32)read_cr2());
270 break;
271 }
272}
273
274static void kvm_mmu_op(void *buffer, unsigned len)
275{
276 int r;
277 unsigned long a1, a2;
278
279 do {
280 a1 = __pa(buffer);
281 a2 = 0; /* on i386 __pa() always returns <4G */
282 r = kvm_hypercall3(KVM_HC_MMU_OP, len, a1, a2);
283 buffer += r;
284 len -= r;
285 } while (len);
286}
287
288static void mmu_queue_flush(struct kvm_para_state *state)
289{
290 if (state->mmu_queue_len) {
291 kvm_mmu_op(state->mmu_queue, state->mmu_queue_len);
292 state->mmu_queue_len = 0;
293 }
294}
295
296static void kvm_deferred_mmu_op(void *buffer, int len)
297{
298 struct kvm_para_state *state = kvm_para_state();
299
300 if (paravirt_get_lazy_mode() != PARAVIRT_LAZY_MMU) {
301 kvm_mmu_op(buffer, len);
302 return;
303 }
304 if (state->mmu_queue_len + len > sizeof state->mmu_queue)
305 mmu_queue_flush(state);
306 memcpy(state->mmu_queue + state->mmu_queue_len, buffer, len);
307 state->mmu_queue_len += len;
308}
309
310static void kvm_mmu_write(void *dest, u64 val)
311{
312 __u64 pte_phys;
313 struct kvm_mmu_op_write_pte wpte;
314
315#ifdef CONFIG_HIGHPTE
316 struct page *page;
317 unsigned long dst = (unsigned long) dest;
318
319 page = kmap_atomic_to_page(dest);
320 pte_phys = page_to_pfn(page);
321 pte_phys <<= PAGE_SHIFT;
322 pte_phys += (dst & ~(PAGE_MASK));
323#else
324 pte_phys = (unsigned long)__pa(dest);
325#endif
326 wpte.header.op = KVM_MMU_OP_WRITE_PTE;
327 wpte.pte_val = val;
328 wpte.pte_phys = pte_phys;
329
330 kvm_deferred_mmu_op(&wpte, sizeof wpte);
331}
332
333/*
334 * We only need to hook operations that are MMU writes. We hook these so that
335 * we can use lazy MMU mode to batch these operations. We could probably
336 * improve the performance of the host code if we used some of the information
337 * here to simplify processing of batched writes.
338 */
339static void kvm_set_pte(pte_t *ptep, pte_t pte)
340{
341 kvm_mmu_write(ptep, pte_val(pte));
342}
343
344static void kvm_set_pte_at(struct mm_struct *mm, unsigned long addr,
345 pte_t *ptep, pte_t pte)
346{
347 kvm_mmu_write(ptep, pte_val(pte));
348}
349
350static void kvm_set_pmd(pmd_t *pmdp, pmd_t pmd)
351{
352 kvm_mmu_write(pmdp, pmd_val(pmd));
353}
354
355#if PAGETABLE_LEVELS >= 3
356#ifdef CONFIG_X86_PAE
357static void kvm_set_pte_atomic(pte_t *ptep, pte_t pte)
358{
359 kvm_mmu_write(ptep, pte_val(pte));
360}
361
362static void kvm_pte_clear(struct mm_struct *mm,
363 unsigned long addr, pte_t *ptep)
364{
365 kvm_mmu_write(ptep, 0);
366}
367
368static void kvm_pmd_clear(pmd_t *pmdp)
369{
370 kvm_mmu_write(pmdp, 0);
371}
372#endif
373
374static void kvm_set_pud(pud_t *pudp, pud_t pud)
375{
376 kvm_mmu_write(pudp, pud_val(pud));
377}
378
379#if PAGETABLE_LEVELS == 4
380static void kvm_set_pgd(pgd_t *pgdp, pgd_t pgd)
381{
382 kvm_mmu_write(pgdp, pgd_val(pgd));
383}
384#endif
385#endif /* PAGETABLE_LEVELS >= 3 */
386
387static void kvm_flush_tlb(void)
388{
389 struct kvm_mmu_op_flush_tlb ftlb = {
390 .header.op = KVM_MMU_OP_FLUSH_TLB,
391 };
392
393 kvm_deferred_mmu_op(&ftlb, sizeof ftlb);
394}
395
396static void kvm_release_pt(unsigned long pfn)
397{
398 struct kvm_mmu_op_release_pt rpt = {
399 .header.op = KVM_MMU_OP_RELEASE_PT,
400 .pt_phys = (u64)pfn << PAGE_SHIFT,
401 };
402
403 kvm_mmu_op(&rpt, sizeof rpt);
404}
405
406static void kvm_enter_lazy_mmu(void)
407{
408 paravirt_enter_lazy_mmu();
409}
410
411static void kvm_leave_lazy_mmu(void)
412{
413 struct kvm_para_state *state = kvm_para_state();
414
415 mmu_queue_flush(state);
416 paravirt_leave_lazy_mmu();
417}
418
419static void __init paravirt_ops_setup(void)
420{
421 pv_info.name = "KVM";
422 pv_info.paravirt_enabled = 1;
423
424 if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
425 pv_cpu_ops.io_delay = kvm_io_delay;
426
427 if (kvm_para_has_feature(KVM_FEATURE_MMU_OP)) {
428 pv_mmu_ops.set_pte = kvm_set_pte;
429 pv_mmu_ops.set_pte_at = kvm_set_pte_at;
430 pv_mmu_ops.set_pmd = kvm_set_pmd;
431#if PAGETABLE_LEVELS >= 3
432#ifdef CONFIG_X86_PAE
433 pv_mmu_ops.set_pte_atomic = kvm_set_pte_atomic;
434 pv_mmu_ops.pte_clear = kvm_pte_clear;
435 pv_mmu_ops.pmd_clear = kvm_pmd_clear;
436#endif
437 pv_mmu_ops.set_pud = kvm_set_pud;
438#if PAGETABLE_LEVELS == 4
439 pv_mmu_ops.set_pgd = kvm_set_pgd;
440#endif
441#endif
442 pv_mmu_ops.flush_tlb_user = kvm_flush_tlb;
443 pv_mmu_ops.release_pte = kvm_release_pt;
444 pv_mmu_ops.release_pmd = kvm_release_pt;
445 pv_mmu_ops.release_pud = kvm_release_pt;
446
447 pv_mmu_ops.lazy_mode.enter = kvm_enter_lazy_mmu;
448 pv_mmu_ops.lazy_mode.leave = kvm_leave_lazy_mmu;
449 }
450#ifdef CONFIG_X86_IO_APIC
451 no_timer_check = 1;
452#endif
453}
454
455static void kvm_register_steal_time(void)
456{
457 int cpu = smp_processor_id();
458 struct kvm_steal_time *st = &per_cpu(steal_time, cpu);
459
460 if (!has_steal_clock)
461 return;
462
463 memset(st, 0, sizeof(*st));
464
465 wrmsrl(MSR_KVM_STEAL_TIME, (__pa(st) | KVM_MSR_ENABLED));
466 printk(KERN_INFO "kvm-stealtime: cpu %d, msr %lx\n",
467 cpu, __pa(st));
468}
469
470void __cpuinit kvm_guest_cpu_init(void)
471{
472 if (!kvm_para_available())
473 return;
474
475 if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf) {
476 u64 pa = __pa(&__get_cpu_var(apf_reason));
477
478#ifdef CONFIG_PREEMPT
479 pa |= KVM_ASYNC_PF_SEND_ALWAYS;
480#endif
481 wrmsrl(MSR_KVM_ASYNC_PF_EN, pa | KVM_ASYNC_PF_ENABLED);
482 __get_cpu_var(apf_reason).enabled = 1;
483 printk(KERN_INFO"KVM setup async PF for cpu %d\n",
484 smp_processor_id());
485 }
486
487 if (has_steal_clock)
488 kvm_register_steal_time();
489}
490
491static void kvm_pv_disable_apf(void *unused)
492{
493 if (!__get_cpu_var(apf_reason).enabled)
494 return;
495
496 wrmsrl(MSR_KVM_ASYNC_PF_EN, 0);
497 __get_cpu_var(apf_reason).enabled = 0;
498
499 printk(KERN_INFO"Unregister pv shared memory for cpu %d\n",
500 smp_processor_id());
501}
502
503static int kvm_pv_reboot_notify(struct notifier_block *nb,
504 unsigned long code, void *unused)
505{
506 if (code == SYS_RESTART)
507 on_each_cpu(kvm_pv_disable_apf, NULL, 1);
508 return NOTIFY_DONE;
509}
510
511static struct notifier_block kvm_pv_reboot_nb = {
512 .notifier_call = kvm_pv_reboot_notify,
513};
514
515static u64 kvm_steal_clock(int cpu)
516{
517 u64 steal;
518 struct kvm_steal_time *src;
519 int version;
520
521 src = &per_cpu(steal_time, cpu);
522 do {
523 version = src->version;
524 rmb();
525 steal = src->steal;
526 rmb();
527 } while ((version & 1) || (version != src->version));
528
529 return steal;
530}
531
532void kvm_disable_steal_time(void)
533{
534 if (!has_steal_clock)
535 return;
536
537 wrmsr(MSR_KVM_STEAL_TIME, 0, 0);
538}
539
540#ifdef CONFIG_SMP
541static void __init kvm_smp_prepare_boot_cpu(void)
542{
543#ifdef CONFIG_KVM_CLOCK
544 WARN_ON(kvm_register_clock("primary cpu clock"));
545#endif
546 kvm_guest_cpu_init();
547 native_smp_prepare_boot_cpu();
548}
549
550static void __cpuinit kvm_guest_cpu_online(void *dummy)
551{
552 kvm_guest_cpu_init();
553}
554
555static void kvm_guest_cpu_offline(void *dummy)
556{
557 kvm_disable_steal_time();
558 kvm_pv_disable_apf(NULL);
559 apf_task_wake_all();
560}
561
562static int __cpuinit kvm_cpu_notify(struct notifier_block *self,
563 unsigned long action, void *hcpu)
564{
565 int cpu = (unsigned long)hcpu;
566 switch (action) {
567 case CPU_ONLINE:
568 case CPU_DOWN_FAILED:
569 case CPU_ONLINE_FROZEN:
570 smp_call_function_single(cpu, kvm_guest_cpu_online, NULL, 0);
571 break;
572 case CPU_DOWN_PREPARE:
573 case CPU_DOWN_PREPARE_FROZEN:
574 smp_call_function_single(cpu, kvm_guest_cpu_offline, NULL, 1);
575 break;
576 default:
577 break;
578 }
579 return NOTIFY_OK;
580}
581
582static struct notifier_block __cpuinitdata kvm_cpu_notifier = {
583 .notifier_call = kvm_cpu_notify,
584};
585#endif
586
587static void __init kvm_apf_trap_init(void)
588{
589 set_intr_gate(14, &async_page_fault);
590}
591
592void __init kvm_guest_init(void)
593{
594 int i;
595
596 if (!kvm_para_available())
597 return;
598
599 paravirt_ops_setup();
600 register_reboot_notifier(&kvm_pv_reboot_nb);
601 for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++)
602 spin_lock_init(&async_pf_sleepers[i].lock);
603 if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF))
604 x86_init.irqs.trap_init = kvm_apf_trap_init;
605
606 if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
607 has_steal_clock = 1;
608 pv_time_ops.steal_clock = kvm_steal_clock;
609 }
610
611#ifdef CONFIG_SMP
612 smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
613 register_cpu_notifier(&kvm_cpu_notifier);
614#else
615 kvm_guest_cpu_init();
616#endif
617}
618
619static __init int activate_jump_labels(void)
620{
621 if (has_steal_clock) {
622 jump_label_inc(¶virt_steal_enabled);
623 if (steal_acc)
624 jump_label_inc(¶virt_steal_rq_enabled);
625 }
626
627 return 0;
628}
629arch_initcall(activate_jump_labels);