30963af5dba02960143f9ebf37b6f85d44de0dec
[linux-2.6.git] / drivers / xen / events.c
1 /*
2  * Xen event channels
3  *
4  * Xen models interrupts with abstract event channels.  Because each
5  * domain gets 1024 event channels, but NR_IRQ is not that large, we
6  * must dynamically map irqs<->event channels.  The event channels
7  * interface with the rest of the kernel by defining a xen interrupt
8  * chip.  When an event is recieved, it is mapped to an irq and sent
9  * through the normal interrupt processing path.
10  *
11  * There are four kinds of events which can be mapped to an event
12  * channel:
13  *
14  * 1. Inter-domain notifications.  This includes all the virtual
15  *    device events, since they're driven by front-ends in another domain
16  *    (typically dom0).
17  * 2. VIRQs, typically used for timers.  These are per-cpu events.
18  * 3. IPIs.
19  * 4. Hardware interrupts. Not supported at present.
20  *
21  * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
22  */
23
24 #include <linux/linkage.h>
25 #include <linux/interrupt.h>
26 #include <linux/irq.h>
27 #include <linux/module.h>
28 #include <linux/string.h>
29 #include <linux/bootmem.h>
30
31 #include <asm/ptrace.h>
32 #include <asm/irq.h>
33 #include <asm/idle.h>
34 #include <asm/sync_bitops.h>
35 #include <asm/xen/hypercall.h>
36 #include <asm/xen/hypervisor.h>
37
38 #include <xen/xen-ops.h>
39 #include <xen/events.h>
40 #include <xen/interface/xen.h>
41 #include <xen/interface/event_channel.h>
42
43 /*
44  * This lock protects updates to the following mapping and reference-count
45  * arrays. The lock does not need to be acquired to read the mapping tables.
46  */
47 static DEFINE_SPINLOCK(irq_mapping_update_lock);
48
49 /* IRQ <-> VIRQ mapping. */
50 static DEFINE_PER_CPU(int, virq_to_irq[NR_VIRQS]) = {[0 ... NR_VIRQS-1] = -1};
51
52 /* IRQ <-> IPI mapping */
53 static DEFINE_PER_CPU(int, ipi_to_irq[XEN_NR_IPIS]) = {[0 ... XEN_NR_IPIS-1] = -1};
54
55 /* Interrupt types. */
56 enum xen_irq_type {
57         IRQT_UNBOUND = 0,
58         IRQT_PIRQ,
59         IRQT_VIRQ,
60         IRQT_IPI,
61         IRQT_EVTCHN
62 };
63
64 /*
65  * Packed IRQ information:
66  * type - enum xen_irq_type
67  * event channel - irq->event channel mapping
68  * cpu - cpu this event channel is bound to
69  * index - type-specific information:
70  *    PIRQ - vector, with MSB being "needs EIO"
71  *    VIRQ - virq number
72  *    IPI - IPI vector
73  *    EVTCHN -
74  */
75 struct irq_info
76 {
77         enum xen_irq_type type; /* type */
78         unsigned short evtchn;  /* event channel */
79         unsigned short cpu;     /* cpu bound */
80
81         union {
82                 unsigned short virq;
83                 enum ipi_vector ipi;
84                 struct {
85                         unsigned short gsi;
86                         unsigned short vector;
87                 } pirq;
88         } u;
89 };
90
91 static struct irq_info irq_info[NR_IRQS];
92
93 static int evtchn_to_irq[NR_EVENT_CHANNELS] = {
94         [0 ... NR_EVENT_CHANNELS-1] = -1
95 };
96 struct cpu_evtchn_s {
97         unsigned long bits[NR_EVENT_CHANNELS/BITS_PER_LONG];
98 };
99 static struct cpu_evtchn_s *cpu_evtchn_mask_p;
100 static inline unsigned long *cpu_evtchn_mask(int cpu)
101 {
102         return cpu_evtchn_mask_p[cpu].bits;
103 }
104
105 /* Xen will never allocate port zero for any purpose. */
106 #define VALID_EVTCHN(chn)       ((chn) != 0)
107
108 static struct irq_chip xen_dynamic_chip;
109
110 /* Constructor for packed IRQ information. */
111 static struct irq_info mk_unbound_info(void)
112 {
113         return (struct irq_info) { .type = IRQT_UNBOUND };
114 }
115
116 static struct irq_info mk_evtchn_info(unsigned short evtchn)
117 {
118         return (struct irq_info) { .type = IRQT_EVTCHN, .evtchn = evtchn,
119                         .cpu = 0 };
120 }
121
122 static struct irq_info mk_ipi_info(unsigned short evtchn, enum ipi_vector ipi)
123 {
124         return (struct irq_info) { .type = IRQT_IPI, .evtchn = evtchn,
125                         .cpu = 0, .u.ipi = ipi };
126 }
127
128 static struct irq_info mk_virq_info(unsigned short evtchn, unsigned short virq)
129 {
130         return (struct irq_info) { .type = IRQT_VIRQ, .evtchn = evtchn,
131                         .cpu = 0, .u.virq = virq };
132 }
133
134 static struct irq_info mk_pirq_info(unsigned short evtchn,
135                                     unsigned short gsi, unsigned short vector)
136 {
137         return (struct irq_info) { .type = IRQT_PIRQ, .evtchn = evtchn,
138                         .cpu = 0, .u.pirq = { .gsi = gsi, .vector = vector } };
139 }
140
141 /*
142  * Accessors for packed IRQ information.
143  */
144 static struct irq_info *info_for_irq(unsigned irq)
145 {
146         return &irq_info[irq];
147 }
148
149 static unsigned int evtchn_from_irq(unsigned irq)
150 {
151         return info_for_irq(irq)->evtchn;
152 }
153
154 static enum ipi_vector ipi_from_irq(unsigned irq)
155 {
156         struct irq_info *info = info_for_irq(irq);
157
158         BUG_ON(info == NULL);
159         BUG_ON(info->type != IRQT_IPI);
160
161         return info->u.ipi;
162 }
163
164 static unsigned virq_from_irq(unsigned irq)
165 {
166         struct irq_info *info = info_for_irq(irq);
167
168         BUG_ON(info == NULL);
169         BUG_ON(info->type != IRQT_VIRQ);
170
171         return info->u.virq;
172 }
173
174 static unsigned gsi_from_irq(unsigned irq)
175 {
176         struct irq_info *info = info_for_irq(irq);
177
178         BUG_ON(info == NULL);
179         BUG_ON(info->type != IRQT_PIRQ);
180
181         return info->u.pirq.gsi;
182 }
183
184 static unsigned vector_from_irq(unsigned irq)
185 {
186         struct irq_info *info = info_for_irq(irq);
187
188         BUG_ON(info == NULL);
189         BUG_ON(info->type != IRQT_PIRQ);
190
191         return info->u.pirq.vector;
192 }
193
194 static enum xen_irq_type type_from_irq(unsigned irq)
195 {
196         return info_for_irq(irq)->type;
197 }
198
199 static unsigned cpu_from_irq(unsigned irq)
200 {
201         return info_for_irq(irq)->cpu;
202 }
203
204 static unsigned int cpu_from_evtchn(unsigned int evtchn)
205 {
206         int irq = evtchn_to_irq[evtchn];
207         unsigned ret = 0;
208
209         if (irq != -1)
210                 ret = cpu_from_irq(irq);
211
212         return ret;
213 }
214
215 static inline unsigned long active_evtchns(unsigned int cpu,
216                                            struct shared_info *sh,
217                                            unsigned int idx)
218 {
219         return (sh->evtchn_pending[idx] &
220                 cpu_evtchn_mask(cpu)[idx] &
221                 ~sh->evtchn_mask[idx]);
222 }
223
224 static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
225 {
226         int irq = evtchn_to_irq[chn];
227
228         BUG_ON(irq == -1);
229 #ifdef CONFIG_SMP
230         cpumask_copy(irq_to_desc(irq)->affinity, cpumask_of(cpu));
231 #endif
232
233         __clear_bit(chn, cpu_evtchn_mask(cpu_from_irq(irq)));
234         __set_bit(chn, cpu_evtchn_mask(cpu));
235
236         irq_info[irq].cpu = cpu;
237 }
238
239 static void init_evtchn_cpu_bindings(void)
240 {
241 #ifdef CONFIG_SMP
242         struct irq_desc *desc;
243         int i;
244
245         /* By default all event channels notify CPU#0. */
246         for_each_irq_desc(i, desc) {
247                 cpumask_copy(desc->affinity, cpumask_of(0));
248         }
249 #endif
250
251         memset(cpu_evtchn_mask(0), ~0, sizeof(cpu_evtchn_mask(0)));
252 }
253
254 static inline void clear_evtchn(int port)
255 {
256         struct shared_info *s = HYPERVISOR_shared_info;
257         sync_clear_bit(port, &s->evtchn_pending[0]);
258 }
259
260 static inline void set_evtchn(int port)
261 {
262         struct shared_info *s = HYPERVISOR_shared_info;
263         sync_set_bit(port, &s->evtchn_pending[0]);
264 }
265
266 static inline int test_evtchn(int port)
267 {
268         struct shared_info *s = HYPERVISOR_shared_info;
269         return sync_test_bit(port, &s->evtchn_pending[0]);
270 }
271
272
273 /**
274  * notify_remote_via_irq - send event to remote end of event channel via irq
275  * @irq: irq of event channel to send event to
276  *
277  * Unlike notify_remote_via_evtchn(), this is safe to use across
278  * save/restore. Notifications on a broken connection are silently
279  * dropped.
280  */
281 void notify_remote_via_irq(int irq)
282 {
283         int evtchn = evtchn_from_irq(irq);
284
285         if (VALID_EVTCHN(evtchn))
286                 notify_remote_via_evtchn(evtchn);
287 }
288 EXPORT_SYMBOL_GPL(notify_remote_via_irq);
289
290 static void mask_evtchn(int port)
291 {
292         struct shared_info *s = HYPERVISOR_shared_info;
293         sync_set_bit(port, &s->evtchn_mask[0]);
294 }
295
296 static void unmask_evtchn(int port)
297 {
298         struct shared_info *s = HYPERVISOR_shared_info;
299         unsigned int cpu = get_cpu();
300
301         BUG_ON(!irqs_disabled());
302
303         /* Slow path (hypercall) if this is a non-local port. */
304         if (unlikely(cpu != cpu_from_evtchn(port))) {
305                 struct evtchn_unmask unmask = { .port = port };
306                 (void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask);
307         } else {
308                 struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
309
310                 sync_clear_bit(port, &s->evtchn_mask[0]);
311
312                 /*
313                  * The following is basically the equivalent of
314                  * 'hw_resend_irq'. Just like a real IO-APIC we 'lose
315                  * the interrupt edge' if the channel is masked.
316                  */
317                 if (sync_test_bit(port, &s->evtchn_pending[0]) &&
318                     !sync_test_and_set_bit(port / BITS_PER_LONG,
319                                            &vcpu_info->evtchn_pending_sel))
320                         vcpu_info->evtchn_upcall_pending = 1;
321         }
322
323         put_cpu();
324 }
325
326 static int find_unbound_irq(void)
327 {
328         int irq;
329         struct irq_desc *desc;
330
331         for (irq = 0; irq < nr_irqs; irq++)
332                 if (irq_info[irq].type == IRQT_UNBOUND)
333                         break;
334
335         if (irq == nr_irqs)
336                 panic("No available IRQ to bind to: increase nr_irqs!\n");
337
338         desc = irq_to_desc_alloc_cpu(irq, 0);
339         if (WARN_ON(desc == NULL))
340                 return -1;
341
342         dynamic_irq_init(irq);
343
344         return irq;
345 }
346
347 int bind_evtchn_to_irq(unsigned int evtchn)
348 {
349         int irq;
350
351         spin_lock(&irq_mapping_update_lock);
352
353         irq = evtchn_to_irq[evtchn];
354
355         if (irq == -1) {
356                 irq = find_unbound_irq();
357
358                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
359                                               handle_level_irq, "event");
360
361                 evtchn_to_irq[evtchn] = irq;
362                 irq_info[irq] = mk_evtchn_info(evtchn);
363         }
364
365         spin_unlock(&irq_mapping_update_lock);
366
367         return irq;
368 }
369 EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);
370
371 static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
372 {
373         struct evtchn_bind_ipi bind_ipi;
374         int evtchn, irq;
375
376         spin_lock(&irq_mapping_update_lock);
377
378         irq = per_cpu(ipi_to_irq, cpu)[ipi];
379
380         if (irq == -1) {
381                 irq = find_unbound_irq();
382                 if (irq < 0)
383                         goto out;
384
385                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
386                                               handle_level_irq, "ipi");
387
388                 bind_ipi.vcpu = cpu;
389                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
390                                                 &bind_ipi) != 0)
391                         BUG();
392                 evtchn = bind_ipi.port;
393
394                 evtchn_to_irq[evtchn] = irq;
395                 irq_info[irq] = mk_ipi_info(evtchn, ipi);
396                 per_cpu(ipi_to_irq, cpu)[ipi] = irq;
397
398                 bind_evtchn_to_cpu(evtchn, cpu);
399         }
400
401  out:
402         spin_unlock(&irq_mapping_update_lock);
403         return irq;
404 }
405
406
407 static int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
408 {
409         struct evtchn_bind_virq bind_virq;
410         int evtchn, irq;
411
412         spin_lock(&irq_mapping_update_lock);
413
414         irq = per_cpu(virq_to_irq, cpu)[virq];
415
416         if (irq == -1) {
417                 bind_virq.virq = virq;
418                 bind_virq.vcpu = cpu;
419                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
420                                                 &bind_virq) != 0)
421                         BUG();
422                 evtchn = bind_virq.port;
423
424                 irq = find_unbound_irq();
425
426                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
427                                               handle_level_irq, "virq");
428
429                 evtchn_to_irq[evtchn] = irq;
430                 irq_info[irq] = mk_virq_info(evtchn, virq);
431
432                 per_cpu(virq_to_irq, cpu)[virq] = irq;
433
434                 bind_evtchn_to_cpu(evtchn, cpu);
435         }
436
437         spin_unlock(&irq_mapping_update_lock);
438
439         return irq;
440 }
441
442 static void unbind_from_irq(unsigned int irq)
443 {
444         struct evtchn_close close;
445         int evtchn = evtchn_from_irq(irq);
446
447         spin_lock(&irq_mapping_update_lock);
448
449         if (VALID_EVTCHN(evtchn)) {
450                 close.port = evtchn;
451                 if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
452                         BUG();
453
454                 switch (type_from_irq(irq)) {
455                 case IRQT_VIRQ:
456                         per_cpu(virq_to_irq, cpu_from_evtchn(evtchn))
457                                 [virq_from_irq(irq)] = -1;
458                         break;
459                 case IRQT_IPI:
460                         per_cpu(ipi_to_irq, cpu_from_evtchn(evtchn))
461                                 [ipi_from_irq(irq)] = -1;
462                         break;
463                 default:
464                         break;
465                 }
466
467                 /* Closed ports are implicitly re-bound to VCPU0. */
468                 bind_evtchn_to_cpu(evtchn, 0);
469
470                 evtchn_to_irq[evtchn] = -1;
471                 irq_info[irq] = mk_unbound_info();
472
473                 dynamic_irq_cleanup(irq);
474         }
475
476         spin_unlock(&irq_mapping_update_lock);
477 }
478
479 int bind_evtchn_to_irqhandler(unsigned int evtchn,
480                               irq_handler_t handler,
481                               unsigned long irqflags,
482                               const char *devname, void *dev_id)
483 {
484         unsigned int irq;
485         int retval;
486
487         irq = bind_evtchn_to_irq(evtchn);
488         retval = request_irq(irq, handler, irqflags, devname, dev_id);
489         if (retval != 0) {
490                 unbind_from_irq(irq);
491                 return retval;
492         }
493
494         return irq;
495 }
496 EXPORT_SYMBOL_GPL(bind_evtchn_to_irqhandler);
497
498 int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
499                             irq_handler_t handler,
500                             unsigned long irqflags, const char *devname, void *dev_id)
501 {
502         unsigned int irq;
503         int retval;
504
505         irq = bind_virq_to_irq(virq, cpu);
506         retval = request_irq(irq, handler, irqflags, devname, dev_id);
507         if (retval != 0) {
508                 unbind_from_irq(irq);
509                 return retval;
510         }
511
512         return irq;
513 }
514 EXPORT_SYMBOL_GPL(bind_virq_to_irqhandler);
515
516 int bind_ipi_to_irqhandler(enum ipi_vector ipi,
517                            unsigned int cpu,
518                            irq_handler_t handler,
519                            unsigned long irqflags,
520                            const char *devname,
521                            void *dev_id)
522 {
523         int irq, retval;
524
525         irq = bind_ipi_to_irq(ipi, cpu);
526         if (irq < 0)
527                 return irq;
528
529         retval = request_irq(irq, handler, irqflags, devname, dev_id);
530         if (retval != 0) {
531                 unbind_from_irq(irq);
532                 return retval;
533         }
534
535         return irq;
536 }
537
538 void unbind_from_irqhandler(unsigned int irq, void *dev_id)
539 {
540         free_irq(irq, dev_id);
541         unbind_from_irq(irq);
542 }
543 EXPORT_SYMBOL_GPL(unbind_from_irqhandler);
544
545 void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
546 {
547         int irq = per_cpu(ipi_to_irq, cpu)[vector];
548         BUG_ON(irq < 0);
549         notify_remote_via_irq(irq);
550 }
551
552 irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
553 {
554         struct shared_info *sh = HYPERVISOR_shared_info;
555         int cpu = smp_processor_id();
556         int i;
557         unsigned long flags;
558         static DEFINE_SPINLOCK(debug_lock);
559
560         spin_lock_irqsave(&debug_lock, flags);
561
562         printk("vcpu %d\n  ", cpu);
563
564         for_each_online_cpu(i) {
565                 struct vcpu_info *v = per_cpu(xen_vcpu, i);
566                 printk("%d: masked=%d pending=%d event_sel %08lx\n  ", i,
567                         (get_irq_regs() && i == cpu) ? xen_irqs_disabled(get_irq_regs()) : v->evtchn_upcall_mask,
568                         v->evtchn_upcall_pending,
569                         v->evtchn_pending_sel);
570         }
571         printk("pending:\n   ");
572         for(i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--)
573                 printk("%08lx%s", sh->evtchn_pending[i],
574                         i % 8 == 0 ? "\n   " : " ");
575         printk("\nmasks:\n   ");
576         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
577                 printk("%08lx%s", sh->evtchn_mask[i],
578                         i % 8 == 0 ? "\n   " : " ");
579
580         printk("\nunmasked:\n   ");
581         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
582                 printk("%08lx%s", sh->evtchn_pending[i] & ~sh->evtchn_mask[i],
583                         i % 8 == 0 ? "\n   " : " ");
584
585         printk("\npending list:\n");
586         for(i = 0; i < NR_EVENT_CHANNELS; i++) {
587                 if (sync_test_bit(i, sh->evtchn_pending)) {
588                         printk("  %d: event %d -> irq %d\n",
589                                cpu_from_evtchn(i), i,
590                                evtchn_to_irq[i]);
591                 }
592         }
593
594         spin_unlock_irqrestore(&debug_lock, flags);
595
596         return IRQ_HANDLED;
597 }
598
599 /*
600  * Search the CPUs pending events bitmasks.  For each one found, map
601  * the event number to an irq, and feed it into do_IRQ() for
602  * handling.
603  *
604  * Xen uses a two-level bitmap to speed searching.  The first level is
605  * a bitset of words which contain pending event bits.  The second
606  * level is a bitset of pending events themselves.
607  */
608 void xen_evtchn_do_upcall(struct pt_regs *regs)
609 {
610         int cpu = get_cpu();
611         struct pt_regs *old_regs = set_irq_regs(regs);
612         struct shared_info *s = HYPERVISOR_shared_info;
613         struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
614         static DEFINE_PER_CPU(unsigned, nesting_count);
615         unsigned count;
616
617         exit_idle();
618         irq_enter();
619
620         do {
621                 unsigned long pending_words;
622
623                 vcpu_info->evtchn_upcall_pending = 0;
624
625                 if (__get_cpu_var(nesting_count)++)
626                         goto out;
627
628 #ifndef CONFIG_X86 /* No need for a barrier -- XCHG is a barrier on x86. */
629                 /* Clear master flag /before/ clearing selector flag. */
630                 wmb();
631 #endif
632                 pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
633                 while (pending_words != 0) {
634                         unsigned long pending_bits;
635                         int word_idx = __ffs(pending_words);
636                         pending_words &= ~(1UL << word_idx);
637
638                         while ((pending_bits = active_evtchns(cpu, s, word_idx)) != 0) {
639                                 int bit_idx = __ffs(pending_bits);
640                                 int port = (word_idx * BITS_PER_LONG) + bit_idx;
641                                 int irq = evtchn_to_irq[port];
642
643                                 if (irq != -1)
644                                         handle_irq(irq, regs);
645                         }
646                 }
647
648                 BUG_ON(!irqs_disabled());
649
650                 count = __get_cpu_var(nesting_count);
651                 __get_cpu_var(nesting_count) = 0;
652         } while(count != 1);
653
654 out:
655         irq_exit();
656         set_irq_regs(old_regs);
657
658         put_cpu();
659 }
660
661 /* Rebind a new event channel to an existing irq. */
662 void rebind_evtchn_irq(int evtchn, int irq)
663 {
664         struct irq_info *info = info_for_irq(irq);
665
666         /* Make sure the irq is masked, since the new event channel
667            will also be masked. */
668         disable_irq(irq);
669
670         spin_lock(&irq_mapping_update_lock);
671
672         /* After resume the irq<->evtchn mappings are all cleared out */
673         BUG_ON(evtchn_to_irq[evtchn] != -1);
674         /* Expect irq to have been bound before,
675            so there should be a proper type */
676         BUG_ON(info->type == IRQT_UNBOUND);
677
678         evtchn_to_irq[evtchn] = irq;
679         irq_info[irq] = mk_evtchn_info(evtchn);
680
681         spin_unlock(&irq_mapping_update_lock);
682
683         /* new event channels are always bound to cpu 0 */
684         irq_set_affinity(irq, cpumask_of(0));
685
686         /* Unmask the event channel. */
687         enable_irq(irq);
688 }
689
690 /* Rebind an evtchn so that it gets delivered to a specific cpu */
691 static void rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
692 {
693         struct evtchn_bind_vcpu bind_vcpu;
694         int evtchn = evtchn_from_irq(irq);
695
696         if (!VALID_EVTCHN(evtchn))
697                 return;
698
699         /* Send future instances of this interrupt to other vcpu. */
700         bind_vcpu.port = evtchn;
701         bind_vcpu.vcpu = tcpu;
702
703         /*
704          * If this fails, it usually just indicates that we're dealing with a
705          * virq or IPI channel, which don't actually need to be rebound. Ignore
706          * it, but don't do the xenlinux-level rebind in that case.
707          */
708         if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
709                 bind_evtchn_to_cpu(evtchn, tcpu);
710 }
711
712
713 static void set_affinity_irq(unsigned irq, const struct cpumask *dest)
714 {
715         unsigned tcpu = cpumask_first(dest);
716         rebind_irq_to_cpu(irq, tcpu);
717 }
718
719 int resend_irq_on_evtchn(unsigned int irq)
720 {
721         int masked, evtchn = evtchn_from_irq(irq);
722         struct shared_info *s = HYPERVISOR_shared_info;
723
724         if (!VALID_EVTCHN(evtchn))
725                 return 1;
726
727         masked = sync_test_and_set_bit(evtchn, s->evtchn_mask);
728         sync_set_bit(evtchn, s->evtchn_pending);
729         if (!masked)
730                 unmask_evtchn(evtchn);
731
732         return 1;
733 }
734
735 static void enable_dynirq(unsigned int irq)
736 {
737         int evtchn = evtchn_from_irq(irq);
738
739         if (VALID_EVTCHN(evtchn))
740                 unmask_evtchn(evtchn);
741 }
742
743 static void disable_dynirq(unsigned int irq)
744 {
745         int evtchn = evtchn_from_irq(irq);
746
747         if (VALID_EVTCHN(evtchn))
748                 mask_evtchn(evtchn);
749 }
750
751 static void ack_dynirq(unsigned int irq)
752 {
753         int evtchn = evtchn_from_irq(irq);
754
755         move_native_irq(irq);
756
757         if (VALID_EVTCHN(evtchn))
758                 clear_evtchn(evtchn);
759 }
760
761 static int retrigger_dynirq(unsigned int irq)
762 {
763         int evtchn = evtchn_from_irq(irq);
764         struct shared_info *sh = HYPERVISOR_shared_info;
765         int ret = 0;
766
767         if (VALID_EVTCHN(evtchn)) {
768                 int masked;
769
770                 masked = sync_test_and_set_bit(evtchn, sh->evtchn_mask);
771                 sync_set_bit(evtchn, sh->evtchn_pending);
772                 if (!masked)
773                         unmask_evtchn(evtchn);
774                 ret = 1;
775         }
776
777         return ret;
778 }
779
780 static void restore_cpu_virqs(unsigned int cpu)
781 {
782         struct evtchn_bind_virq bind_virq;
783         int virq, irq, evtchn;
784
785         for (virq = 0; virq < NR_VIRQS; virq++) {
786                 if ((irq = per_cpu(virq_to_irq, cpu)[virq]) == -1)
787                         continue;
788
789                 BUG_ON(virq_from_irq(irq) != virq);
790
791                 /* Get a new binding from Xen. */
792                 bind_virq.virq = virq;
793                 bind_virq.vcpu = cpu;
794                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
795                                                 &bind_virq) != 0)
796                         BUG();
797                 evtchn = bind_virq.port;
798
799                 /* Record the new mapping. */
800                 evtchn_to_irq[evtchn] = irq;
801                 irq_info[irq] = mk_virq_info(evtchn, virq);
802                 bind_evtchn_to_cpu(evtchn, cpu);
803
804                 /* Ready for use. */
805                 unmask_evtchn(evtchn);
806         }
807 }
808
809 static void restore_cpu_ipis(unsigned int cpu)
810 {
811         struct evtchn_bind_ipi bind_ipi;
812         int ipi, irq, evtchn;
813
814         for (ipi = 0; ipi < XEN_NR_IPIS; ipi++) {
815                 if ((irq = per_cpu(ipi_to_irq, cpu)[ipi]) == -1)
816                         continue;
817
818                 BUG_ON(ipi_from_irq(irq) != ipi);
819
820                 /* Get a new binding from Xen. */
821                 bind_ipi.vcpu = cpu;
822                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
823                                                 &bind_ipi) != 0)
824                         BUG();
825                 evtchn = bind_ipi.port;
826
827                 /* Record the new mapping. */
828                 evtchn_to_irq[evtchn] = irq;
829                 irq_info[irq] = mk_ipi_info(evtchn, ipi);
830                 bind_evtchn_to_cpu(evtchn, cpu);
831
832                 /* Ready for use. */
833                 unmask_evtchn(evtchn);
834
835         }
836 }
837
838 /* Clear an irq's pending state, in preparation for polling on it */
839 void xen_clear_irq_pending(int irq)
840 {
841         int evtchn = evtchn_from_irq(irq);
842
843         if (VALID_EVTCHN(evtchn))
844                 clear_evtchn(evtchn);
845 }
846
847 void xen_set_irq_pending(int irq)
848 {
849         int evtchn = evtchn_from_irq(irq);
850
851         if (VALID_EVTCHN(evtchn))
852                 set_evtchn(evtchn);
853 }
854
855 bool xen_test_irq_pending(int irq)
856 {
857         int evtchn = evtchn_from_irq(irq);
858         bool ret = false;
859
860         if (VALID_EVTCHN(evtchn))
861                 ret = test_evtchn(evtchn);
862
863         return ret;
864 }
865
866 /* Poll waiting for an irq to become pending.  In the usual case, the
867    irq will be disabled so it won't deliver an interrupt. */
868 void xen_poll_irq(int irq)
869 {
870         evtchn_port_t evtchn = evtchn_from_irq(irq);
871
872         if (VALID_EVTCHN(evtchn)) {
873                 struct sched_poll poll;
874
875                 poll.nr_ports = 1;
876                 poll.timeout = 0;
877                 set_xen_guest_handle(poll.ports, &evtchn);
878
879                 if (HYPERVISOR_sched_op(SCHEDOP_poll, &poll) != 0)
880                         BUG();
881         }
882 }
883
884 void xen_irq_resume(void)
885 {
886         unsigned int cpu, irq, evtchn;
887
888         init_evtchn_cpu_bindings();
889
890         /* New event-channel space is not 'live' yet. */
891         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
892                 mask_evtchn(evtchn);
893
894         /* No IRQ <-> event-channel mappings. */
895         for (irq = 0; irq < nr_irqs; irq++)
896                 irq_info[irq].evtchn = 0; /* zap event-channel binding */
897
898         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
899                 evtchn_to_irq[evtchn] = -1;
900
901         for_each_possible_cpu(cpu) {
902                 restore_cpu_virqs(cpu);
903                 restore_cpu_ipis(cpu);
904         }
905 }
906
907 static struct irq_chip xen_dynamic_chip __read_mostly = {
908         .name           = "xen-dyn",
909
910         .disable        = disable_dynirq,
911         .mask           = disable_dynirq,
912         .unmask         = enable_dynirq,
913
914         .ack            = ack_dynirq,
915         .set_affinity   = set_affinity_irq,
916         .retrigger      = retrigger_dynirq,
917 };
918
919 void __init xen_init_IRQ(void)
920 {
921         int i;
922         size_t size = nr_cpu_ids * sizeof(struct cpu_evtchn_s);
923
924         cpu_evtchn_mask_p = alloc_bootmem(size);
925         BUG_ON(cpu_evtchn_mask_p == NULL);
926
927         init_evtchn_cpu_bindings();
928
929         /* No event channels are 'live' right now. */
930         for (i = 0; i < NR_EVENT_CHANNELS; i++)
931                 mask_evtchn(i);
932
933         irq_ctx_init(smp_processor_id());
934 }