SAFE public projects git trees. - safe/jmp/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 }
 120
 121 static struct irq_info mk_ipi_info(unsigned short evtchn, enum ipi_vector ipi)
 122 {
 123         return (struct irq_info) { .type = IRQT_IPI, .evtchn = evtchn,
 124                         .u.ipi = ipi };
 125 }
 126
 127 static struct irq_info mk_virq_info(unsigned short evtchn, unsigned short virq)
 128 {
 129         return (struct irq_info) { .type = IRQT_VIRQ, .evtchn = evtchn,
 130                         .u.virq = virq };
 131 }
 132
 133 static struct irq_info mk_pirq_info(unsigned short evtchn,
 134                                     unsigned short gsi, unsigned short vector)
 135 {
 136         return (struct irq_info) { .type = IRQT_PIRQ, .evtchn = evtchn,
 137                         .u.pirq = { .gsi = gsi, .vector = vector } };
 138 }
 139
 140 /*
 141  * Accessors for packed IRQ information.
 142  */
 143 static struct irq_info *info_for_irq(unsigned irq)
 144 {
 145         return &irq_info[irq];
 146 }
 147
 148 static unsigned int evtchn_from_irq(unsigned irq)
 149 {
 150         return info_for_irq(irq)->evtchn;
 151 }
 152
 153 static enum ipi_vector ipi_from_irq(unsigned irq)
 154 {
 155         struct irq_info *info = info_for_irq(irq);
 156
 157         BUG_ON(info == NULL);
 158         BUG_ON(info->type != IRQT_IPI);
 159
 160         return info->u.ipi;
 161 }
 162
 163 static unsigned virq_from_irq(unsigned irq)
 164 {
 165         struct irq_info *info = info_for_irq(irq);
 166
 167         BUG_ON(info == NULL);
 168         BUG_ON(info->type != IRQT_VIRQ);
 169
 170         return info->u.virq;
 171 }
 172
 173 static unsigned gsi_from_irq(unsigned irq)
 174 {
 175         struct irq_info *info = info_for_irq(irq);
 176
 177         BUG_ON(info == NULL);
 178         BUG_ON(info->type != IRQT_PIRQ);
 179
 180         return info->u.pirq.gsi;
 181 }
 182
 183 static unsigned vector_from_irq(unsigned irq)
 184 {
 185         struct irq_info *info = info_for_irq(irq);
 186
 187         BUG_ON(info == NULL);
 188         BUG_ON(info->type != IRQT_PIRQ);
 189
 190         return info->u.pirq.vector;
 191 }
 192
 193 static enum xen_irq_type type_from_irq(unsigned irq)
 194 {
 195         return info_for_irq(irq)->type;
 196 }
 197
 198 static unsigned cpu_from_irq(unsigned irq)
 199 {
 200         return info_for_irq(irq)->cpu;
 201 }
 202
 203 static unsigned int cpu_from_evtchn(unsigned int evtchn)
 204 {
 205         int irq = evtchn_to_irq[evtchn];
 206         unsigned ret = 0;
 207
 208         if (irq != -1)
 209                 ret = cpu_from_irq(irq);
 210
 211         return ret;
 212 }
 213
 214 static inline unsigned long active_evtchns(unsigned int cpu,
 215                                            struct shared_info *sh,
 216                                            unsigned int idx)
 217 {
 218         return (sh->evtchn_pending[idx] &
 219                 cpu_evtchn_mask(cpu)[idx] &
 220                 ~sh->evtchn_mask[idx]);
 221 }
 222
 223 static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
 224 {
 225         int irq = evtchn_to_irq[chn];
 226
 227         BUG_ON(irq == -1);
 228 #ifdef CONFIG_SMP
 229         cpumask_copy(irq_to_desc(irq)->affinity, cpumask_of(cpu));
 230 #endif
 231
 232         __clear_bit(chn, cpu_evtchn_mask(cpu_from_irq(irq)));
 233         __set_bit(chn, cpu_evtchn_mask(cpu));
 234
 235         irq_info[irq].cpu = cpu;
 236 }
 237
 238 static void init_evtchn_cpu_bindings(void)
 239 {
 240 #ifdef CONFIG_SMP
 241         struct irq_desc *desc;
 242         int i;
 243
 244         /* By default all event channels notify CPU#0. */
 245         for_each_irq_desc(i, desc) {
 246                 cpumask_copy(desc->affinity, cpumask_of(0));
 247         }
 248 #endif
 249
 250         memset(cpu_evtchn_mask(0), ~0, sizeof(cpu_evtchn_mask(0)));
 251 }
 252
 253 static inline void clear_evtchn(int port)
 254 {
 255         struct shared_info *s = HYPERVISOR_shared_info;
 256         sync_clear_bit(port, &s->evtchn_pending[0]);
 257 }
 258
 259 static inline void set_evtchn(int port)
 260 {
 261         struct shared_info *s = HYPERVISOR_shared_info;
 262         sync_set_bit(port, &s->evtchn_pending[0]);
 263 }
 264
 265 static inline int test_evtchn(int port)
 266 {
 267         struct shared_info *s = HYPERVISOR_shared_info;
 268         return sync_test_bit(port, &s->evtchn_pending[0]);
 269 }
 270
 271
 272 /**
 273  * notify_remote_via_irq - send event to remote end of event channel via irq
 274  * @irq: irq of event channel to send event to
 275  *
 276  * Unlike notify_remote_via_evtchn(), this is safe to use across
 277  * save/restore. Notifications on a broken connection are silently
 278  * dropped.
 279  */
 280 void notify_remote_via_irq(int irq)
 281 {
 282         int evtchn = evtchn_from_irq(irq);
 283
 284         if (VALID_EVTCHN(evtchn))
 285                 notify_remote_via_evtchn(evtchn);
 286 }
 287 EXPORT_SYMBOL_GPL(notify_remote_via_irq);
 288
 289 static void mask_evtchn(int port)
 290 {
 291         struct shared_info *s = HYPERVISOR_shared_info;
 292         sync_set_bit(port, &s->evtchn_mask[0]);
 293 }
 294
 295 static void unmask_evtchn(int port)
 296 {
 297         struct shared_info *s = HYPERVISOR_shared_info;
 298         unsigned int cpu = get_cpu();
 299
 300         BUG_ON(!irqs_disabled());
 301
 302         /* Slow path (hypercall) if this is a non-local port. */
 303         if (unlikely(cpu != cpu_from_evtchn(port))) {
 304                 struct evtchn_unmask unmask = { .port = port };
 305                 (void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask);
 306         } else {
 307                 struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
 308
 309                 sync_clear_bit(port, &s->evtchn_mask[0]);
 310
 311                 /*
 312                  * The following is basically the equivalent of
 313                  * 'hw_resend_irq'. Just like a real IO-APIC we 'lose
 314                  * the interrupt edge' if the channel is masked.
 315                  */
 316                 if (sync_test_bit(port, &s->evtchn_pending[0]) &&
 317                     !sync_test_and_set_bit(port / BITS_PER_LONG,
 318                                            &vcpu_info->evtchn_pending_sel))
 319                         vcpu_info->evtchn_upcall_pending = 1;
 320         }
 321
 322         put_cpu();
 323 }
 324
 325 static int find_unbound_irq(void)
 326 {
 327         int irq;
 328         struct irq_desc *desc;
 329
 330         for (irq = 0; irq < nr_irqs; irq++)
 331                 if (irq_info[irq].type == IRQT_UNBOUND)
 332                         break;
 333
 334         if (irq == nr_irqs)
 335                 panic("No available IRQ to bind to: increase nr_irqs!\n");
 336
 337         desc = irq_to_desc_alloc_cpu(irq, 0);
 338         if (WARN_ON(desc == NULL))
 339                 return -1;
 340
 341         dynamic_irq_init(irq);
 342
 343         return irq;
 344 }
 345
 346 int bind_evtchn_to_irq(unsigned int evtchn)
 347 {
 348         int irq;
 349
 350         spin_lock(&irq_mapping_update_lock);
 351
 352         irq = evtchn_to_irq[evtchn];
 353
 354         if (irq == -1) {
 355                 irq = find_unbound_irq();
 356
 357                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 358                                               handle_level_irq, "event");
 359
 360                 evtchn_to_irq[evtchn] = irq;
 361                 irq_info[irq] = mk_evtchn_info(evtchn);
 362         }
 363
 364         spin_unlock(&irq_mapping_update_lock);
 365
 366         return irq;
 367 }
 368 EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);
 369
 370 static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
 371 {
 372         struct evtchn_bind_ipi bind_ipi;
 373         int evtchn, irq;
 374
 375         spin_lock(&irq_mapping_update_lock);
 376
 377         irq = per_cpu(ipi_to_irq, cpu)[ipi];
 378         if (irq == -1) {
 379                 irq = find_unbound_irq();
 380                 if (irq < 0)
 381                         goto out;
 382
 383                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 384                                               handle_level_irq, "ipi");
 385
 386                 bind_ipi.vcpu = cpu;
 387                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
 388                                                 &bind_ipi) != 0)
 389                         BUG();
 390                 evtchn = bind_ipi.port;
 391
 392                 evtchn_to_irq[evtchn] = irq;
 393                 irq_info[irq] = mk_ipi_info(evtchn, ipi);
 394
 395                 per_cpu(ipi_to_irq, cpu)[ipi] = irq;
 396
 397                 bind_evtchn_to_cpu(evtchn, cpu);
 398         }
 399
 400  out:
 401         spin_unlock(&irq_mapping_update_lock);
 402         return irq;
 403 }
 404
 405
 406 static int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 407 {
 408         struct evtchn_bind_virq bind_virq;
 409         int evtchn, irq;
 410
 411         spin_lock(&irq_mapping_update_lock);
 412
 413         irq = per_cpu(virq_to_irq, cpu)[virq];
 414
 415         if (irq == -1) {
 416                 bind_virq.virq = virq;
 417                 bind_virq.vcpu = cpu;
 418                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
 419                                                 &bind_virq) != 0)
 420                         BUG();
 421                 evtchn = bind_virq.port;
 422
 423                 irq = find_unbound_irq();
 424
 425                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 426                                               handle_level_irq, "virq");
 427
 428                 evtchn_to_irq[evtchn] = irq;
 429                 irq_info[irq] = mk_virq_info(evtchn, virq);
 430
 431                 per_cpu(virq_to_irq, cpu)[virq] = irq;
 432
 433                 bind_evtchn_to_cpu(evtchn, cpu);
 434         }
 435
 436         spin_unlock(&irq_mapping_update_lock);
 437
 438         return irq;
 439 }
 440
 441 static void unbind_from_irq(unsigned int irq)
 442 {
 443         struct evtchn_close close;
 444         int evtchn = evtchn_from_irq(irq);
 445
 446         spin_lock(&irq_mapping_update_lock);
 447
 448         if (VALID_EVTCHN(evtchn)) {
 449                 close.port = evtchn;
 450                 if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
 451                         BUG();
 452
 453                 switch (type_from_irq(irq)) {
 454                 case IRQT_VIRQ:
 455                         per_cpu(virq_to_irq, cpu_from_evtchn(evtchn))
 456                                 [virq_from_irq(irq)] = -1;
 457                         break;
 458                 case IRQT_IPI:
 459                         per_cpu(ipi_to_irq, cpu_from_evtchn(evtchn))
 460                                 [ipi_from_irq(irq)] = -1;
 461                         break;
 462                 default:
 463                         break;
 464                 }
 465
 466                 /* Closed ports are implicitly re-bound to VCPU0. */
 467                 bind_evtchn_to_cpu(evtchn, 0);
 468
 469                 evtchn_to_irq[evtchn] = -1;
 470                 irq_info[irq] = mk_unbound_info();
 471
 472                 dynamic_irq_cleanup(irq);
 473         }
 474
 475         spin_unlock(&irq_mapping_update_lock);
 476 }
 477
 478 int bind_evtchn_to_irqhandler(unsigned int evtchn,
 479                               irq_handler_t handler,
 480                               unsigned long irqflags,
 481                               const char *devname, void *dev_id)
 482 {
 483         unsigned int irq;
 484         int retval;
 485
 486         irq = bind_evtchn_to_irq(evtchn);
 487         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 488         if (retval != 0) {
 489                 unbind_from_irq(irq);
 490                 return retval;
 491         }
 492
 493         return irq;
 494 }
 495 EXPORT_SYMBOL_GPL(bind_evtchn_to_irqhandler);
 496
 497 int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
 498                             irq_handler_t handler,
 499                             unsigned long irqflags, const char *devname, void *dev_id)
 500 {
 501         unsigned int irq;
 502         int retval;
 503
 504         irq = bind_virq_to_irq(virq, cpu);
 505         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 506         if (retval != 0) {
 507                 unbind_from_irq(irq);
 508                 return retval;
 509         }
 510
 511         return irq;
 512 }
 513 EXPORT_SYMBOL_GPL(bind_virq_to_irqhandler);
 514
 515 int bind_ipi_to_irqhandler(enum ipi_vector ipi,
 516                            unsigned int cpu,
 517                            irq_handler_t handler,
 518                            unsigned long irqflags,
 519                            const char *devname,
 520                            void *dev_id)
 521 {
 522         int irq, retval;
 523
 524         irq = bind_ipi_to_irq(ipi, cpu);
 525         if (irq < 0)
 526                 return irq;
 527
 528         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 529         if (retval != 0) {
 530                 unbind_from_irq(irq);
 531                 return retval;
 532         }
 533
 534         return irq;
 535 }
 536
 537 void unbind_from_irqhandler(unsigned int irq, void *dev_id)
 538 {
 539         free_irq(irq, dev_id);
 540         unbind_from_irq(irq);
 541 }
 542 EXPORT_SYMBOL_GPL(unbind_from_irqhandler);
 543
 544 void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
 545 {
 546         int irq = per_cpu(ipi_to_irq, cpu)[vector];
 547         BUG_ON(irq < 0);
 548         notify_remote_via_irq(irq);
 549 }
 550
 551 irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 552 {
 553         struct shared_info *sh = HYPERVISOR_shared_info;
 554         int cpu = smp_processor_id();
 555         int i;
 556         unsigned long flags;
 557         static DEFINE_SPINLOCK(debug_lock);
 558
 559         spin_lock_irqsave(&debug_lock, flags);
 560
 561         printk("vcpu %d\n  ", cpu);
 562
 563         for_each_online_cpu(i) {
 564                 struct vcpu_info *v = per_cpu(xen_vcpu, i);
 565                 printk("%d: masked=%d pending=%d event_sel %08lx\n  ", i,
 566                         (get_irq_regs() && i == cpu) ? xen_irqs_disabled(get_irq_regs()) : v->evtchn_upcall_mask,
 567                         v->evtchn_upcall_pending,
 568                         v->evtchn_pending_sel);
 569         }
 570         printk("pending:\n   ");
 571         for(i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--)
 572                 printk("%08lx%s", sh->evtchn_pending[i],
 573                         i % 8 == 0 ? "\n   " : " ");
 574         printk("\nmasks:\n   ");
 575         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
 576                 printk("%08lx%s", sh->evtchn_mask[i],
 577                         i % 8 == 0 ? "\n   " : " ");
 578
 579         printk("\nunmasked:\n   ");
 580         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
 581                 printk("%08lx%s", sh->evtchn_pending[i] & ~sh->evtchn_mask[i],
 582                         i % 8 == 0 ? "\n   " : " ");
 583
 584         printk("\npending list:\n");
 585         for(i = 0; i < NR_EVENT_CHANNELS; i++) {
 586                 if (sync_test_bit(i, sh->evtchn_pending)) {
 587                         printk("  %d: event %d -> irq %d\n",
 588                                cpu_from_evtchn(i), i,
 589                                evtchn_to_irq[i]);
 590                 }
 591         }
 592
 593         spin_unlock_irqrestore(&debug_lock, flags);
 594
 595         return IRQ_HANDLED;
 596 }
 597
 598
 599 static void xen_do_irq(unsigned irq, struct pt_regs *regs)
 600 {
 601         struct pt_regs *old_regs = set_irq_regs(regs);
 602
 603         if (WARN_ON(irq == -1))
 604                 return;
 605
 606         exit_idle();
 607         irq_enter();
 608
 609         //printk("cpu %d handling irq %d\n", smp_processor_id(), info->irq);
 610         handle_irq(irq, regs);
 611
 612         irq_exit();
 613
 614         set_irq_regs(old_regs);
 615 }
 616
 617 /*
 618  * Search the CPUs pending events bitmasks.  For each one found, map
 619  * the event number to an irq, and feed it into do_IRQ() for
 620  * handling.
 621  *
 622  * Xen uses a two-level bitmap to speed searching.  The first level is
 623  * a bitset of words which contain pending event bits.  The second
 624  * level is a bitset of pending events themselves.
 625  */
 626 void xen_evtchn_do_upcall(struct pt_regs *regs)
 627 {
 628         int cpu = get_cpu();
 629         struct shared_info *s = HYPERVISOR_shared_info;
 630         struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
 631         static DEFINE_PER_CPU(unsigned, nesting_count);
 632         unsigned count;
 633
 634         do {
 635                 unsigned long pending_words;
 636
 637                 vcpu_info->evtchn_upcall_pending = 0;
 638
 639                 if (__get_cpu_var(nesting_count)++)
 640                         goto out;
 641
 642 #ifndef CONFIG_X86 /* No need for a barrier -- XCHG is a barrier on x86. */
 643                 /* Clear master flag /before/ clearing selector flag. */
 644                 wmb();
 645 #endif
 646                 pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
 647                 while (pending_words != 0) {
 648                         unsigned long pending_bits;
 649                         int word_idx = __ffs(pending_words);
 650                         pending_words &= ~(1UL << word_idx);
 651
 652                         while ((pending_bits = active_evtchns(cpu, s, word_idx)) != 0) {
 653                                 int bit_idx = __ffs(pending_bits);
 654                                 int port = (word_idx * BITS_PER_LONG) + bit_idx;
 655                                 int irq = evtchn_to_irq[port];
 656
 657                                 xen_do_irq(irq, regs);
 658                         }
 659                 }
 660
 661                 BUG_ON(!irqs_disabled());
 662
 663                 count = __get_cpu_var(nesting_count);
 664                 __get_cpu_var(nesting_count) = 0;
 665         } while(count != 1);
 666
 667 out:
 668         put_cpu();
 669 }
 670
 671 /* Rebind a new event channel to an existing irq. */
 672 void rebind_evtchn_irq(int evtchn, int irq)
 673 {
 674         struct irq_info *info = info_for_irq(irq);
 675
 676         /* Make sure the irq is masked, since the new event channel
 677            will also be masked. */
 678         disable_irq(irq);
 679
 680         spin_lock(&irq_mapping_update_lock);
 681
 682         /* After resume the irq<->evtchn mappings are all cleared out */
 683         BUG_ON(evtchn_to_irq[evtchn] != -1);
 684         /* Expect irq to have been bound before,
 685            so there should be a proper type */
 686         BUG_ON(info->type == IRQT_UNBOUND);
 687
 688         evtchn_to_irq[evtchn] = irq;
 689         irq_info[irq] = mk_evtchn_info(evtchn);
 690
 691         spin_unlock(&irq_mapping_update_lock);
 692
 693         /* new event channels are always bound to cpu 0 */
 694         irq_set_affinity(irq, cpumask_of(0));
 695
 696         /* Unmask the event channel. */
 697         enable_irq(irq);
 698 }
 699
 700 /* Rebind an evtchn so that it gets delivered to a specific cpu */
 701 static void rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
 702 {
 703         struct evtchn_bind_vcpu bind_vcpu;
 704         int evtchn = evtchn_from_irq(irq);
 705
 706         if (!VALID_EVTCHN(evtchn))
 707                 return;
 708
 709         /* Send future instances of this interrupt to other vcpu. */
 710         bind_vcpu.port = evtchn;
 711         bind_vcpu.vcpu = tcpu;
 712
 713         /*
 714          * If this fails, it usually just indicates that we're dealing with a
 715          * virq or IPI channel, which don't actually need to be rebound. Ignore
 716          * it, but don't do the xenlinux-level rebind in that case.
 717          */
 718         if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
 719                 bind_evtchn_to_cpu(evtchn, tcpu);
 720 }
 721
 722
 723 static void set_affinity_irq(unsigned irq, const struct cpumask *dest)
 724 {
 725         unsigned tcpu = cpumask_first(dest);
 726         rebind_irq_to_cpu(irq, tcpu);
 727 }
 728
 729 int resend_irq_on_evtchn(unsigned int irq)
 730 {
 731         int masked, evtchn = evtchn_from_irq(irq);
 732         struct shared_info *s = HYPERVISOR_shared_info;
 733
 734         if (!VALID_EVTCHN(evtchn))
 735                 return 1;
 736
 737         masked = sync_test_and_set_bit(evtchn, s->evtchn_mask);
 738         sync_set_bit(evtchn, s->evtchn_pending);
 739         if (!masked)
 740                 unmask_evtchn(evtchn);
 741
 742         return 1;
 743 }
 744
 745 static void enable_dynirq(unsigned int irq)
 746 {
 747         int evtchn = evtchn_from_irq(irq);
 748
 749         if (VALID_EVTCHN(evtchn))
 750                 unmask_evtchn(evtchn);
 751 }
 752
 753 static void disable_dynirq(unsigned int irq)
 754 {
 755         int evtchn = evtchn_from_irq(irq);
 756
 757         if (VALID_EVTCHN(evtchn))
 758                 mask_evtchn(evtchn);
 759 }
 760
 761 static void ack_dynirq(unsigned int irq)
 762 {
 763         int evtchn = evtchn_from_irq(irq);
 764
 765         move_native_irq(irq);
 766
 767         if (VALID_EVTCHN(evtchn))
 768                 clear_evtchn(evtchn);
 769 }
 770
 771 static int retrigger_dynirq(unsigned int irq)
 772 {
 773         int evtchn = evtchn_from_irq(irq);
 774         struct shared_info *sh = HYPERVISOR_shared_info;
 775         int ret = 0;
 776
 777         if (VALID_EVTCHN(evtchn)) {
 778                 int masked;
 779
 780                 masked = sync_test_and_set_bit(evtchn, sh->evtchn_mask);
 781                 sync_set_bit(evtchn, sh->evtchn_pending);
 782                 if (!masked)
 783                         unmask_evtchn(evtchn);
 784                 ret = 1;
 785         }
 786
 787         return ret;
 788 }
 789
 790 static void restore_cpu_virqs(unsigned int cpu)
 791 {
 792         struct evtchn_bind_virq bind_virq;
 793         int virq, irq, evtchn;
 794
 795         for (virq = 0; virq < NR_VIRQS; virq++) {
 796                 if ((irq = per_cpu(virq_to_irq, cpu)[virq]) == -1)
 797                         continue;
 798
 799                 BUG_ON(virq_from_irq(irq) != virq);
 800
 801                 /* Get a new binding from Xen. */
 802                 bind_virq.virq = virq;
 803                 bind_virq.vcpu = cpu;
 804                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
 805                                                 &bind_virq) != 0)
 806                         BUG();
 807                 evtchn = bind_virq.port;
 808
 809                 /* Record the new mapping. */
 810                 evtchn_to_irq[evtchn] = irq;
 811                 irq_info[irq] = mk_virq_info(evtchn, virq);
 812                 bind_evtchn_to_cpu(evtchn, cpu);
 813
 814                 /* Ready for use. */
 815                 unmask_evtchn(evtchn);
 816         }
 817 }
 818
 819 static void restore_cpu_ipis(unsigned int cpu)
 820 {
 821         struct evtchn_bind_ipi bind_ipi;
 822         int ipi, irq, evtchn;
 823
 824         for (ipi = 0; ipi < XEN_NR_IPIS; ipi++) {
 825                 if ((irq = per_cpu(ipi_to_irq, cpu)[ipi]) == -1)
 826                         continue;
 827
 828                 BUG_ON(ipi_from_irq(irq) != ipi);
 829
 830                 /* Get a new binding from Xen. */
 831                 bind_ipi.vcpu = cpu;
 832                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
 833                                                 &bind_ipi) != 0)
 834                         BUG();
 835                 evtchn = bind_ipi.port;
 836
 837                 /* Record the new mapping. */
 838                 evtchn_to_irq[evtchn] = irq;
 839                 irq_info[irq] = mk_ipi_info(evtchn, ipi);
 840                 bind_evtchn_to_cpu(evtchn, cpu);
 841
 842                 /* Ready for use. */
 843                 unmask_evtchn(evtchn);
 844
 845         }
 846 }
 847
 848 /* Clear an irq's pending state, in preparation for polling on it */
 849 void xen_clear_irq_pending(int irq)
 850 {
 851         int evtchn = evtchn_from_irq(irq);
 852
 853         if (VALID_EVTCHN(evtchn))
 854                 clear_evtchn(evtchn);
 855 }
 856
 857 void xen_set_irq_pending(int irq)
 858 {
 859         int evtchn = evtchn_from_irq(irq);
 860
 861         if (VALID_EVTCHN(evtchn))
 862                 set_evtchn(evtchn);
 863 }
 864
 865 bool xen_test_irq_pending(int irq)
 866 {
 867         int evtchn = evtchn_from_irq(irq);
 868         bool ret = false;
 869
 870         if (VALID_EVTCHN(evtchn))
 871                 ret = test_evtchn(evtchn);
 872
 873         return ret;
 874 }
 875
 876 /* Poll waiting for an irq to become pending.  In the usual case, the
 877    irq will be disabled so it won't deliver an interrupt. */
 878 void xen_poll_irq(int irq)
 879 {
 880         evtchn_port_t evtchn = evtchn_from_irq(irq);
 881
 882         if (VALID_EVTCHN(evtchn)) {
 883                 struct sched_poll poll;
 884
 885                 poll.nr_ports = 1;
 886                 poll.timeout = 0;
 887                 set_xen_guest_handle(poll.ports, &evtchn);
 888
 889                 if (HYPERVISOR_sched_op(SCHEDOP_poll, &poll) != 0)
 890                         BUG();
 891         }
 892 }
 893
 894 void xen_irq_resume(void)
 895 {
 896         unsigned int cpu, irq, evtchn;
 897
 898         init_evtchn_cpu_bindings();
 899
 900         /* New event-channel space is not 'live' yet. */
 901         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
 902                 mask_evtchn(evtchn);
 903
 904         /* No IRQ <-> event-channel mappings. */
 905         for (irq = 0; irq < nr_irqs; irq++)
 906                 irq_info[irq].evtchn = 0; /* zap event-channel binding */
 907
 908         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
 909                 evtchn_to_irq[evtchn] = -1;
 910
 911         for_each_possible_cpu(cpu) {
 912                 restore_cpu_virqs(cpu);
 913                 restore_cpu_ipis(cpu);
 914         }
 915 }
 916
 917 static struct irq_chip xen_dynamic_chip __read_mostly = {
 918         .name           = "xen-dyn",
 919
 920         .disable        = disable_dynirq,
 921         .mask           = disable_dynirq,
 922         .unmask         = enable_dynirq,
 923
 924         .ack            = ack_dynirq,
 925         .set_affinity   = set_affinity_irq,
 926         .retrigger      = retrigger_dynirq,
 927 };
 928
 929 void __init xen_init_IRQ(void)
 930 {
 931         int i;
 932         size_t size = nr_cpu_ids * sizeof(struct cpu_evtchn_s);
 933
 934         cpu_evtchn_mask_p = alloc_bootmem(size);
 935         BUG_ON(cpu_evtchn_mask_p == NULL);
 936
 937         init_evtchn_cpu_bindings();
 938
 939         /* No event channels are 'live' right now. */
 940         for (i = 0; i < NR_EVENT_CHANNELS; i++)
 941                 mask_evtchn(i);
 942
 943         irq_ctx_init(smp_processor_id());
 944 }