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 unsigned irq_from_evtchn(unsigned int evtchn)
 155 {
 156         return evtchn_to_irq[evtchn];
 157 }
 158 EXPORT_SYMBOL_GPL(irq_from_evtchn);
 159
 160 static enum ipi_vector ipi_from_irq(unsigned irq)
 161 {
 162         struct irq_info *info = info_for_irq(irq);
 163
 164         BUG_ON(info == NULL);
 165         BUG_ON(info->type != IRQT_IPI);
 166
 167         return info->u.ipi;
 168 }
 169
 170 static unsigned virq_from_irq(unsigned irq)
 171 {
 172         struct irq_info *info = info_for_irq(irq);
 173
 174         BUG_ON(info == NULL);
 175         BUG_ON(info->type != IRQT_VIRQ);
 176
 177         return info->u.virq;
 178 }
 179
 180 static unsigned gsi_from_irq(unsigned irq)
 181 {
 182         struct irq_info *info = info_for_irq(irq);
 183
 184         BUG_ON(info == NULL);
 185         BUG_ON(info->type != IRQT_PIRQ);
 186
 187         return info->u.pirq.gsi;
 188 }
 189
 190 static unsigned vector_from_irq(unsigned irq)
 191 {
 192         struct irq_info *info = info_for_irq(irq);
 193
 194         BUG_ON(info == NULL);
 195         BUG_ON(info->type != IRQT_PIRQ);
 196
 197         return info->u.pirq.vector;
 198 }
 199
 200 static enum xen_irq_type type_from_irq(unsigned irq)
 201 {
 202         return info_for_irq(irq)->type;
 203 }
 204
 205 static unsigned cpu_from_irq(unsigned irq)
 206 {
 207         return info_for_irq(irq)->cpu;
 208 }
 209
 210 static unsigned int cpu_from_evtchn(unsigned int evtchn)
 211 {
 212         int irq = evtchn_to_irq[evtchn];
 213         unsigned ret = 0;
 214
 215         if (irq != -1)
 216                 ret = cpu_from_irq(irq);
 217
 218         return ret;
 219 }
 220
 221 static inline unsigned long active_evtchns(unsigned int cpu,
 222                                            struct shared_info *sh,
 223                                            unsigned int idx)
 224 {
 225         return (sh->evtchn_pending[idx] &
 226                 cpu_evtchn_mask(cpu)[idx] &
 227                 ~sh->evtchn_mask[idx]);
 228 }
 229
 230 static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
 231 {
 232         int irq = evtchn_to_irq[chn];
 233
 234         BUG_ON(irq == -1);
 235 #ifdef CONFIG_SMP
 236         cpumask_copy(irq_to_desc(irq)->affinity, cpumask_of(cpu));
 237 #endif
 238
 239         __clear_bit(chn, cpu_evtchn_mask(cpu_from_irq(irq)));
 240         __set_bit(chn, cpu_evtchn_mask(cpu));
 241
 242         irq_info[irq].cpu = cpu;
 243 }
 244
 245 static void init_evtchn_cpu_bindings(void)
 246 {
 247 #ifdef CONFIG_SMP
 248         struct irq_desc *desc;
 249         int i;
 250
 251         /* By default all event channels notify CPU#0. */
 252         for_each_irq_desc(i, desc) {
 253                 cpumask_copy(desc->affinity, cpumask_of(0));
 254         }
 255 #endif
 256
 257         memset(cpu_evtchn_mask(0), ~0, sizeof(cpu_evtchn_mask(0)));
 258 }
 259
 260 static inline void clear_evtchn(int port)
 261 {
 262         struct shared_info *s = HYPERVISOR_shared_info;
 263         sync_clear_bit(port, &s->evtchn_pending[0]);
 264 }
 265
 266 static inline void set_evtchn(int port)
 267 {
 268         struct shared_info *s = HYPERVISOR_shared_info;
 269         sync_set_bit(port, &s->evtchn_pending[0]);
 270 }
 271
 272 static inline int test_evtchn(int port)
 273 {
 274         struct shared_info *s = HYPERVISOR_shared_info;
 275         return sync_test_bit(port, &s->evtchn_pending[0]);
 276 }
 277
 278
 279 /**
 280  * notify_remote_via_irq - send event to remote end of event channel via irq
 281  * @irq: irq of event channel to send event to
 282  *
 283  * Unlike notify_remote_via_evtchn(), this is safe to use across
 284  * save/restore. Notifications on a broken connection are silently
 285  * dropped.
 286  */
 287 void notify_remote_via_irq(int irq)
 288 {
 289         int evtchn = evtchn_from_irq(irq);
 290
 291         if (VALID_EVTCHN(evtchn))
 292                 notify_remote_via_evtchn(evtchn);
 293 }
 294 EXPORT_SYMBOL_GPL(notify_remote_via_irq);
 295
 296 static void mask_evtchn(int port)
 297 {
 298         struct shared_info *s = HYPERVISOR_shared_info;
 299         sync_set_bit(port, &s->evtchn_mask[0]);
 300 }
 301
 302 static void unmask_evtchn(int port)
 303 {
 304         struct shared_info *s = HYPERVISOR_shared_info;
 305         unsigned int cpu = get_cpu();
 306
 307         BUG_ON(!irqs_disabled());
 308
 309         /* Slow path (hypercall) if this is a non-local port. */
 310         if (unlikely(cpu != cpu_from_evtchn(port))) {
 311                 struct evtchn_unmask unmask = { .port = port };
 312                 (void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask);
 313         } else {
 314                 struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
 315
 316                 sync_clear_bit(port, &s->evtchn_mask[0]);
 317
 318                 /*
 319                  * The following is basically the equivalent of
 320                  * 'hw_resend_irq'. Just like a real IO-APIC we 'lose
 321                  * the interrupt edge' if the channel is masked.
 322                  */
 323                 if (sync_test_bit(port, &s->evtchn_pending[0]) &&
 324                     !sync_test_and_set_bit(port / BITS_PER_LONG,
 325                                            &vcpu_info->evtchn_pending_sel))
 326                         vcpu_info->evtchn_upcall_pending = 1;
 327         }
 328
 329         put_cpu();
 330 }
 331
 332 static int find_unbound_irq(void)
 333 {
 334         int irq;
 335         struct irq_desc *desc;
 336
 337         for (irq = 0; irq < nr_irqs; irq++)
 338                 if (irq_info[irq].type == IRQT_UNBOUND)
 339                         break;
 340
 341         if (irq == nr_irqs)
 342                 panic("No available IRQ to bind to: increase nr_irqs!\n");
 343
 344         desc = irq_to_desc_alloc_node(irq, 0);
 345         if (WARN_ON(desc == NULL))
 346                 return -1;
 347
 348         dynamic_irq_init(irq);
 349
 350         return irq;
 351 }
 352
 353 int bind_evtchn_to_irq(unsigned int evtchn)
 354 {
 355         int irq;
 356
 357         spin_lock(&irq_mapping_update_lock);
 358
 359         irq = evtchn_to_irq[evtchn];
 360
 361         if (irq == -1) {
 362                 irq = find_unbound_irq();
 363
 364                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 365                                               handle_level_irq, "event");
 366
 367                 evtchn_to_irq[evtchn] = irq;
 368                 irq_info[irq] = mk_evtchn_info(evtchn);
 369         }
 370
 371         spin_unlock(&irq_mapping_update_lock);
 372
 373         return irq;
 374 }
 375 EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);
 376
 377 static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
 378 {
 379         struct evtchn_bind_ipi bind_ipi;
 380         int evtchn, irq;
 381
 382         spin_lock(&irq_mapping_update_lock);
 383
 384         irq = per_cpu(ipi_to_irq, cpu)[ipi];
 385
 386         if (irq == -1) {
 387                 irq = find_unbound_irq();
 388                 if (irq < 0)
 389                         goto out;
 390
 391                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 392                                               handle_level_irq, "ipi");
 393
 394                 bind_ipi.vcpu = cpu;
 395                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
 396                                                 &bind_ipi) != 0)
 397                         BUG();
 398                 evtchn = bind_ipi.port;
 399
 400                 evtchn_to_irq[evtchn] = irq;
 401                 irq_info[irq] = mk_ipi_info(evtchn, ipi);
 402                 per_cpu(ipi_to_irq, cpu)[ipi] = irq;
 403
 404                 bind_evtchn_to_cpu(evtchn, cpu);
 405         }
 406
 407  out:
 408         spin_unlock(&irq_mapping_update_lock);
 409         return irq;
 410 }
 411
 412
 413 static int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 414 {
 415         struct evtchn_bind_virq bind_virq;
 416         int evtchn, irq;
 417
 418         spin_lock(&irq_mapping_update_lock);
 419
 420         irq = per_cpu(virq_to_irq, cpu)[virq];
 421
 422         if (irq == -1) {
 423                 bind_virq.virq = virq;
 424                 bind_virq.vcpu = cpu;
 425                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
 426                                                 &bind_virq) != 0)
 427                         BUG();
 428                 evtchn = bind_virq.port;
 429
 430                 irq = find_unbound_irq();
 431
 432                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 433                                               handle_level_irq, "virq");
 434
 435                 evtchn_to_irq[evtchn] = irq;
 436                 irq_info[irq] = mk_virq_info(evtchn, virq);
 437
 438                 per_cpu(virq_to_irq, cpu)[virq] = irq;
 439
 440                 bind_evtchn_to_cpu(evtchn, cpu);
 441         }
 442
 443         spin_unlock(&irq_mapping_update_lock);
 444
 445         return irq;
 446 }
 447
 448 static void unbind_from_irq(unsigned int irq)
 449 {
 450         struct evtchn_close close;
 451         int evtchn = evtchn_from_irq(irq);
 452
 453         spin_lock(&irq_mapping_update_lock);
 454
 455         if (VALID_EVTCHN(evtchn)) {
 456                 close.port = evtchn;
 457                 if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
 458                         BUG();
 459
 460                 switch (type_from_irq(irq)) {
 461                 case IRQT_VIRQ:
 462                         per_cpu(virq_to_irq, cpu_from_evtchn(evtchn))
 463                                 [virq_from_irq(irq)] = -1;
 464                         break;
 465                 case IRQT_IPI:
 466                         per_cpu(ipi_to_irq, cpu_from_evtchn(evtchn))
 467                                 [ipi_from_irq(irq)] = -1;
 468                         break;
 469                 default:
 470                         break;
 471                 }
 472
 473                 /* Closed ports are implicitly re-bound to VCPU0. */
 474                 bind_evtchn_to_cpu(evtchn, 0);
 475
 476                 evtchn_to_irq[evtchn] = -1;
 477                 irq_info[irq] = mk_unbound_info();
 478
 479                 dynamic_irq_cleanup(irq);
 480         }
 481
 482         spin_unlock(&irq_mapping_update_lock);
 483 }
 484
 485 int bind_evtchn_to_irqhandler(unsigned int evtchn,
 486                               irq_handler_t handler,
 487                               unsigned long irqflags,
 488                               const char *devname, void *dev_id)
 489 {
 490         unsigned int irq;
 491         int retval;
 492
 493         irq = bind_evtchn_to_irq(evtchn);
 494         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 495         if (retval != 0) {
 496                 unbind_from_irq(irq);
 497                 return retval;
 498         }
 499
 500         return irq;
 501 }
 502 EXPORT_SYMBOL_GPL(bind_evtchn_to_irqhandler);
 503
 504 int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
 505                             irq_handler_t handler,
 506                             unsigned long irqflags, const char *devname, void *dev_id)
 507 {
 508         unsigned int irq;
 509         int retval;
 510
 511         irq = bind_virq_to_irq(virq, cpu);
 512         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 513         if (retval != 0) {
 514                 unbind_from_irq(irq);
 515                 return retval;
 516         }
 517
 518         return irq;
 519 }
 520 EXPORT_SYMBOL_GPL(bind_virq_to_irqhandler);
 521
 522 int bind_ipi_to_irqhandler(enum ipi_vector ipi,
 523                            unsigned int cpu,
 524                            irq_handler_t handler,
 525                            unsigned long irqflags,
 526                            const char *devname,
 527                            void *dev_id)
 528 {
 529         int irq, retval;
 530
 531         irq = bind_ipi_to_irq(ipi, cpu);
 532         if (irq < 0)
 533                 return irq;
 534
 535         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 536         if (retval != 0) {
 537                 unbind_from_irq(irq);
 538                 return retval;
 539         }
 540
 541         return irq;
 542 }
 543
 544 void unbind_from_irqhandler(unsigned int irq, void *dev_id)
 545 {
 546         free_irq(irq, dev_id);
 547         unbind_from_irq(irq);
 548 }
 549 EXPORT_SYMBOL_GPL(unbind_from_irqhandler);
 550
 551 void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
 552 {
 553         int irq = per_cpu(ipi_to_irq, cpu)[vector];
 554         BUG_ON(irq < 0);
 555         notify_remote_via_irq(irq);
 556 }
 557
 558 irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 559 {
 560         struct shared_info *sh = HYPERVISOR_shared_info;
 561         int cpu = smp_processor_id();
 562         int i;
 563         unsigned long flags;
 564         static DEFINE_SPINLOCK(debug_lock);
 565
 566         spin_lock_irqsave(&debug_lock, flags);
 567
 568         printk("vcpu %d\n  ", cpu);
 569
 570         for_each_online_cpu(i) {
 571                 struct vcpu_info *v = per_cpu(xen_vcpu, i);
 572                 printk("%d: masked=%d pending=%d event_sel %08lx\n  ", i,
 573                         (get_irq_regs() && i == cpu) ? xen_irqs_disabled(get_irq_regs()) : v->evtchn_upcall_mask,
 574                         v->evtchn_upcall_pending,
 575                         v->evtchn_pending_sel);
 576         }
 577         printk("pending:\n   ");
 578         for(i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--)
 579                 printk("%08lx%s", sh->evtchn_pending[i],
 580                         i % 8 == 0 ? "\n   " : " ");
 581         printk("\nmasks:\n   ");
 582         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
 583                 printk("%08lx%s", sh->evtchn_mask[i],
 584                         i % 8 == 0 ? "\n   " : " ");
 585
 586         printk("\nunmasked:\n   ");
 587         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
 588                 printk("%08lx%s", sh->evtchn_pending[i] & ~sh->evtchn_mask[i],
 589                         i % 8 == 0 ? "\n   " : " ");
 590
 591         printk("\npending list:\n");
 592         for(i = 0; i < NR_EVENT_CHANNELS; i++) {
 593                 if (sync_test_bit(i, sh->evtchn_pending)) {
 594                         printk("  %d: event %d -> irq %d\n",
 595                                cpu_from_evtchn(i), i,
 596                                evtchn_to_irq[i]);
 597                 }
 598         }
 599
 600         spin_unlock_irqrestore(&debug_lock, flags);
 601
 602         return IRQ_HANDLED;
 603 }
 604
 605 /*
 606  * Search the CPUs pending events bitmasks.  For each one found, map
 607  * the event number to an irq, and feed it into do_IRQ() for
 608  * handling.
 609  *
 610  * Xen uses a two-level bitmap to speed searching.  The first level is
 611  * a bitset of words which contain pending event bits.  The second
 612  * level is a bitset of pending events themselves.
 613  */
 614 void xen_evtchn_do_upcall(struct pt_regs *regs)
 615 {
 616         int cpu = get_cpu();
 617         struct pt_regs *old_regs = set_irq_regs(regs);
 618         struct shared_info *s = HYPERVISOR_shared_info;
 619         struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
 620         static DEFINE_PER_CPU(unsigned, nesting_count);
 621         unsigned count;
 622
 623         exit_idle();
 624         irq_enter();
 625
 626         do {
 627                 unsigned long pending_words;
 628
 629                 vcpu_info->evtchn_upcall_pending = 0;
 630
 631                 if (__get_cpu_var(nesting_count)++)
 632                         goto out;
 633
 634 #ifndef CONFIG_X86 /* No need for a barrier -- XCHG is a barrier on x86. */
 635                 /* Clear master flag /before/ clearing selector flag. */
 636                 wmb();
 637 #endif
 638                 pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
 639                 while (pending_words != 0) {
 640                         unsigned long pending_bits;
 641                         int word_idx = __ffs(pending_words);
 642                         pending_words &= ~(1UL << word_idx);
 643
 644                         while ((pending_bits = active_evtchns(cpu, s, word_idx)) != 0) {
 645                                 int bit_idx = __ffs(pending_bits);
 646                                 int port = (word_idx * BITS_PER_LONG) + bit_idx;
 647                                 int irq = evtchn_to_irq[port];
 648
 649                                 if (irq != -1)
 650                                         handle_irq(irq, regs);
 651                         }
 652                 }
 653
 654                 BUG_ON(!irqs_disabled());
 655
 656                 count = __get_cpu_var(nesting_count);
 657                 __get_cpu_var(nesting_count) = 0;
 658         } while(count != 1);
 659
 660 out:
 661         irq_exit();
 662         set_irq_regs(old_regs);
 663
 664         put_cpu();
 665 }
 666
 667 /* Rebind a new event channel to an existing irq. */
 668 void rebind_evtchn_irq(int evtchn, int irq)
 669 {
 670         struct irq_info *info = info_for_irq(irq);
 671
 672         /* Make sure the irq is masked, since the new event channel
 673            will also be masked. */
 674         disable_irq(irq);
 675
 676         spin_lock(&irq_mapping_update_lock);
 677
 678         /* After resume the irq<->evtchn mappings are all cleared out */
 679         BUG_ON(evtchn_to_irq[evtchn] != -1);
 680         /* Expect irq to have been bound before,
 681            so there should be a proper type */
 682         BUG_ON(info->type == IRQT_UNBOUND);
 683
 684         evtchn_to_irq[evtchn] = irq;
 685         irq_info[irq] = mk_evtchn_info(evtchn);
 686
 687         spin_unlock(&irq_mapping_update_lock);
 688
 689         /* new event channels are always bound to cpu 0 */
 690         irq_set_affinity(irq, cpumask_of(0));
 691
 692         /* Unmask the event channel. */
 693         enable_irq(irq);
 694 }
 695
 696 /* Rebind an evtchn so that it gets delivered to a specific cpu */
 697 static int rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
 698 {
 699         struct evtchn_bind_vcpu bind_vcpu;
 700         int evtchn = evtchn_from_irq(irq);
 701
 702         if (!VALID_EVTCHN(evtchn))
 703                 return -1;
 704
 705         /* Send future instances of this interrupt to other vcpu. */
 706         bind_vcpu.port = evtchn;
 707         bind_vcpu.vcpu = tcpu;
 708
 709         /*
 710          * If this fails, it usually just indicates that we're dealing with a
 711          * virq or IPI channel, which don't actually need to be rebound. Ignore
 712          * it, but don't do the xenlinux-level rebind in that case.
 713          */
 714         if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
 715                 bind_evtchn_to_cpu(evtchn, tcpu);
 716
 717         return 0;
 718 }
 719
 720 static int set_affinity_irq(unsigned irq, const struct cpumask *dest)
 721 {
 722         unsigned tcpu = cpumask_first(dest);
 723
 724         return rebind_irq_to_cpu(irq, tcpu);
 725 }
 726
 727 int resend_irq_on_evtchn(unsigned int irq)
 728 {
 729         int masked, evtchn = evtchn_from_irq(irq);
 730         struct shared_info *s = HYPERVISOR_shared_info;
 731
 732         if (!VALID_EVTCHN(evtchn))
 733                 return 1;
 734
 735         masked = sync_test_and_set_bit(evtchn, s->evtchn_mask);
 736         sync_set_bit(evtchn, s->evtchn_pending);
 737         if (!masked)
 738                 unmask_evtchn(evtchn);
 739
 740         return 1;
 741 }
 742
 743 static void enable_dynirq(unsigned int irq)
 744 {
 745         int evtchn = evtchn_from_irq(irq);
 746
 747         if (VALID_EVTCHN(evtchn))
 748                 unmask_evtchn(evtchn);
 749 }
 750
 751 static void disable_dynirq(unsigned int irq)
 752 {
 753         int evtchn = evtchn_from_irq(irq);
 754
 755         if (VALID_EVTCHN(evtchn))
 756                 mask_evtchn(evtchn);
 757 }
 758
 759 static void ack_dynirq(unsigned int irq)
 760 {
 761         int evtchn = evtchn_from_irq(irq);
 762
 763         move_native_irq(irq);
 764
 765         if (VALID_EVTCHN(evtchn))
 766                 clear_evtchn(evtchn);
 767 }
 768
 769 static int retrigger_dynirq(unsigned int irq)
 770 {
 771         int evtchn = evtchn_from_irq(irq);
 772         struct shared_info *sh = HYPERVISOR_shared_info;
 773         int ret = 0;
 774
 775         if (VALID_EVTCHN(evtchn)) {
 776                 int masked;
 777
 778                 masked = sync_test_and_set_bit(evtchn, sh->evtchn_mask);
 779                 sync_set_bit(evtchn, sh->evtchn_pending);
 780                 if (!masked)
 781                         unmask_evtchn(evtchn);
 782                 ret = 1;
 783         }
 784
 785         return ret;
 786 }
 787
 788 static void restore_cpu_virqs(unsigned int cpu)
 789 {
 790         struct evtchn_bind_virq bind_virq;
 791         int virq, irq, evtchn;
 792
 793         for (virq = 0; virq < NR_VIRQS; virq++) {
 794                 if ((irq = per_cpu(virq_to_irq, cpu)[virq]) == -1)
 795                         continue;
 796
 797                 BUG_ON(virq_from_irq(irq) != virq);
 798
 799                 /* Get a new binding from Xen. */
 800                 bind_virq.virq = virq;
 801                 bind_virq.vcpu = cpu;
 802                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
 803                                                 &bind_virq) != 0)
 804                         BUG();
 805                 evtchn = bind_virq.port;
 806
 807                 /* Record the new mapping. */
 808                 evtchn_to_irq[evtchn] = irq;
 809                 irq_info[irq] = mk_virq_info(evtchn, virq);
 810                 bind_evtchn_to_cpu(evtchn, cpu);
 811
 812                 /* Ready for use. */
 813                 unmask_evtchn(evtchn);
 814         }
 815 }
 816
 817 static void restore_cpu_ipis(unsigned int cpu)
 818 {
 819         struct evtchn_bind_ipi bind_ipi;
 820         int ipi, irq, evtchn;
 821
 822         for (ipi = 0; ipi < XEN_NR_IPIS; ipi++) {
 823                 if ((irq = per_cpu(ipi_to_irq, cpu)[ipi]) == -1)
 824                         continue;
 825
 826                 BUG_ON(ipi_from_irq(irq) != ipi);
 827
 828                 /* Get a new binding from Xen. */
 829                 bind_ipi.vcpu = cpu;
 830                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
 831                                                 &bind_ipi) != 0)
 832                         BUG();
 833                 evtchn = bind_ipi.port;
 834
 835                 /* Record the new mapping. */
 836                 evtchn_to_irq[evtchn] = irq;
 837                 irq_info[irq] = mk_ipi_info(evtchn, ipi);
 838                 bind_evtchn_to_cpu(evtchn, cpu);
 839
 840                 /* Ready for use. */
 841                 unmask_evtchn(evtchn);
 842
 843         }
 844 }
 845
 846 /* Clear an irq's pending state, in preparation for polling on it */
 847 void xen_clear_irq_pending(int irq)
 848 {
 849         int evtchn = evtchn_from_irq(irq);
 850
 851         if (VALID_EVTCHN(evtchn))
 852                 clear_evtchn(evtchn);
 853 }
 854
 855 void xen_set_irq_pending(int irq)
 856 {
 857         int evtchn = evtchn_from_irq(irq);
 858
 859         if (VALID_EVTCHN(evtchn))
 860                 set_evtchn(evtchn);
 861 }
 862
 863 bool xen_test_irq_pending(int irq)
 864 {
 865         int evtchn = evtchn_from_irq(irq);
 866         bool ret = false;
 867
 868         if (VALID_EVTCHN(evtchn))
 869                 ret = test_evtchn(evtchn);
 870
 871         return ret;
 872 }
 873
 874 /* Poll waiting for an irq to become pending.  In the usual case, the
 875    irq will be disabled so it won't deliver an interrupt. */
 876 void xen_poll_irq(int irq)
 877 {
 878         evtchn_port_t evtchn = evtchn_from_irq(irq);
 879
 880         if (VALID_EVTCHN(evtchn)) {
 881                 struct sched_poll poll;
 882
 883                 poll.nr_ports = 1;
 884                 poll.timeout = 0;
 885                 set_xen_guest_handle(poll.ports, &evtchn);
 886
 887                 if (HYPERVISOR_sched_op(SCHEDOP_poll, &poll) != 0)
 888                         BUG();
 889         }
 890 }
 891
 892 void xen_irq_resume(void)
 893 {
 894         unsigned int cpu, irq, evtchn;
 895
 896         init_evtchn_cpu_bindings();
 897
 898         /* New event-channel space is not 'live' yet. */
 899         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
 900                 mask_evtchn(evtchn);
 901
 902         /* No IRQ <-> event-channel mappings. */
 903         for (irq = 0; irq < nr_irqs; irq++)
 904                 irq_info[irq].evtchn = 0; /* zap event-channel binding */
 905
 906         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
 907                 evtchn_to_irq[evtchn] = -1;
 908
 909         for_each_possible_cpu(cpu) {
 910                 restore_cpu_virqs(cpu);
 911                 restore_cpu_ipis(cpu);
 912         }
 913 }
 914
 915 static struct irq_chip xen_dynamic_chip __read_mostly = {
 916         .name           = "xen-dyn",
 917
 918         .disable        = disable_dynirq,
 919         .mask           = disable_dynirq,
 920         .unmask         = enable_dynirq,
 921
 922         .ack            = ack_dynirq,
 923         .set_affinity   = set_affinity_irq,
 924         .retrigger      = retrigger_dynirq,
 925 };
 926
 927 void __init xen_init_IRQ(void)
 928 {
 929         int i;
 930         size_t size = nr_cpu_ids * sizeof(struct cpu_evtchn_s);
 931
 932         cpu_evtchn_mask_p = alloc_bootmem(size);
 933         BUG_ON(cpu_evtchn_mask_p == NULL);
 934
 935         init_evtchn_cpu_bindings();
 936
 937         /* No event channels are 'live' right now. */
 938         for (i = 0; i < NR_EVENT_CHANNELS; i++)
 939                 mask_evtchn(i);
 940
 941         irq_ctx_init(smp_processor_id());
 942 }