git.oblomov.eu Git - linux-2.6/blob - 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 }