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. PIRQs - Hardware interrupts.
  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 #include <linux/slab.h>
  31 #include <linux/irqnr.h>
  32
  33 #include <asm/desc.h>
  34 #include <asm/ptrace.h>
  35 #include <asm/irq.h>
  36 #include <asm/idle.h>
  37 #include <asm/io_apic.h>
  38 #include <asm/sync_bitops.h>
  39 #include <asm/xen/pci.h>
  40 #include <asm/xen/hypercall.h>
  41 #include <asm/xen/hypervisor.h>
  42
  43 #include <xen/xen.h>
  44 #include <xen/hvm.h>
  45 #include <xen/xen-ops.h>
  46 #include <xen/events.h>
  47 #include <xen/interface/xen.h>
  48 #include <xen/interface/event_channel.h>
  49 #include <xen/interface/hvm/hvm_op.h>
  50 #include <xen/interface/hvm/params.h>
  51
  52 /*
  53  * This lock protects updates to the following mapping and reference-count
  54  * arrays. The lock does not need to be acquired to read the mapping tables.
  55  */
  56 static DEFINE_SPINLOCK(irq_mapping_update_lock);
  57
  58 /* IRQ <-> VIRQ mapping. */
  59 static DEFINE_PER_CPU(int [NR_VIRQS], virq_to_irq) = {[0 ... NR_VIRQS-1] = -1};
  60
  61 /* IRQ <-> IPI mapping */
  62 static DEFINE_PER_CPU(int [XEN_NR_IPIS], ipi_to_irq) = {[0 ... XEN_NR_IPIS-1] = -1};
  63
  64 /* Interrupt types. */
  65 enum xen_irq_type {
  66         IRQT_UNBOUND = 0,
  67         IRQT_PIRQ,
  68         IRQT_VIRQ,
  69         IRQT_IPI,
  70         IRQT_EVTCHN
  71 };
  72
  73 /*
  74  * Packed IRQ information:
  75  * type - enum xen_irq_type
  76  * event channel - irq->event channel mapping
  77  * cpu - cpu this event channel is bound to
  78  * index - type-specific information:
  79  *    PIRQ - vector, with MSB being "needs EIO", or physical IRQ of the HVM
  80  *           guest, or GSI (real passthrough IRQ) of the device.
  81  *    VIRQ - virq number
  82  *    IPI - IPI vector
  83  *    EVTCHN -
  84  */
  85 struct irq_info
  86 {
  87         enum xen_irq_type type; /* type */
  88         unsigned short evtchn;  /* event channel */
  89         unsigned short cpu;     /* cpu bound */
  90
  91         union {
  92                 unsigned short virq;
  93                 enum ipi_vector ipi;
  94                 struct {
  95                         unsigned short pirq;
  96                         unsigned short gsi;
  97                         unsigned char vector;
  98                         unsigned char flags;
  99                 } pirq;
 100         } u;
 101 };
 102 #define PIRQ_NEEDS_EOI  (1 << 0)
 103 #define PIRQ_SHAREABLE  (1 << 1)
 104
 105 static struct irq_info *irq_info;
 106 static int *pirq_to_irq;
 107 static int nr_pirqs;
 108
 109 static int *evtchn_to_irq;
 110 struct cpu_evtchn_s {
 111         unsigned long bits[NR_EVENT_CHANNELS/BITS_PER_LONG];
 112 };
 113
 114 static __initdata struct cpu_evtchn_s init_evtchn_mask = {
 115         .bits[0 ... (NR_EVENT_CHANNELS/BITS_PER_LONG)-1] = ~0ul,
 116 };
 117 static struct cpu_evtchn_s *cpu_evtchn_mask_p = &init_evtchn_mask;
 118
 119 static inline unsigned long *cpu_evtchn_mask(int cpu)
 120 {
 121         return cpu_evtchn_mask_p[cpu].bits;
 122 }
 123
 124 /* Xen will never allocate port zero for any purpose. */
 125 #define VALID_EVTCHN(chn)       ((chn) != 0)
 126
 127 static struct irq_chip xen_dynamic_chip;
 128 static struct irq_chip xen_percpu_chip;
 129 static struct irq_chip xen_pirq_chip;
 130
 131 /* Constructor for packed IRQ information. */
 132 static struct irq_info mk_unbound_info(void)
 133 {
 134         return (struct irq_info) { .type = IRQT_UNBOUND };
 135 }
 136
 137 static struct irq_info mk_evtchn_info(unsigned short evtchn)
 138 {
 139         return (struct irq_info) { .type = IRQT_EVTCHN, .evtchn = evtchn,
 140                         .cpu = 0 };
 141 }
 142
 143 static struct irq_info mk_ipi_info(unsigned short evtchn, enum ipi_vector ipi)
 144 {
 145         return (struct irq_info) { .type = IRQT_IPI, .evtchn = evtchn,
 146                         .cpu = 0, .u.ipi = ipi };
 147 }
 148
 149 static struct irq_info mk_virq_info(unsigned short evtchn, unsigned short virq)
 150 {
 151         return (struct irq_info) { .type = IRQT_VIRQ, .evtchn = evtchn,
 152                         .cpu = 0, .u.virq = virq };
 153 }
 154
 155 static struct irq_info mk_pirq_info(unsigned short evtchn, unsigned short pirq,
 156                                     unsigned short gsi, unsigned short vector)
 157 {
 158         return (struct irq_info) { .type = IRQT_PIRQ, .evtchn = evtchn,
 159                         .cpu = 0,
 160                         .u.pirq = { .pirq = pirq, .gsi = gsi, .vector = vector } };
 161 }
 162
 163 /*
 164  * Accessors for packed IRQ information.
 165  */
 166 static struct irq_info *info_for_irq(unsigned irq)
 167 {
 168         return &irq_info[irq];
 169 }
 170
 171 static unsigned int evtchn_from_irq(unsigned irq)
 172 {
 173         return info_for_irq(irq)->evtchn;
 174 }
 175
 176 unsigned irq_from_evtchn(unsigned int evtchn)
 177 {
 178         return evtchn_to_irq[evtchn];
 179 }
 180 EXPORT_SYMBOL_GPL(irq_from_evtchn);
 181
 182 static enum ipi_vector ipi_from_irq(unsigned irq)
 183 {
 184         struct irq_info *info = info_for_irq(irq);
 185
 186         BUG_ON(info == NULL);
 187         BUG_ON(info->type != IRQT_IPI);
 188
 189         return info->u.ipi;
 190 }
 191
 192 static unsigned virq_from_irq(unsigned irq)
 193 {
 194         struct irq_info *info = info_for_irq(irq);
 195
 196         BUG_ON(info == NULL);
 197         BUG_ON(info->type != IRQT_VIRQ);
 198
 199         return info->u.virq;
 200 }
 201
 202 static unsigned pirq_from_irq(unsigned irq)
 203 {
 204         struct irq_info *info = info_for_irq(irq);
 205
 206         BUG_ON(info == NULL);
 207         BUG_ON(info->type != IRQT_PIRQ);
 208
 209         return info->u.pirq.pirq;
 210 }
 211
 212 static unsigned gsi_from_irq(unsigned irq)
 213 {
 214         struct irq_info *info = info_for_irq(irq);
 215
 216         BUG_ON(info == NULL);
 217         BUG_ON(info->type != IRQT_PIRQ);
 218
 219         return info->u.pirq.gsi;
 220 }
 221
 222 static unsigned vector_from_irq(unsigned irq)
 223 {
 224         struct irq_info *info = info_for_irq(irq);
 225
 226         BUG_ON(info == NULL);
 227         BUG_ON(info->type != IRQT_PIRQ);
 228
 229         return info->u.pirq.vector;
 230 }
 231
 232 static enum xen_irq_type type_from_irq(unsigned irq)
 233 {
 234         return info_for_irq(irq)->type;
 235 }
 236
 237 static unsigned cpu_from_irq(unsigned irq)
 238 {
 239         return info_for_irq(irq)->cpu;
 240 }
 241
 242 static unsigned int cpu_from_evtchn(unsigned int evtchn)
 243 {
 244         int irq = evtchn_to_irq[evtchn];
 245         unsigned ret = 0;
 246
 247         if (irq != -1)
 248                 ret = cpu_from_irq(irq);
 249
 250         return ret;
 251 }
 252
 253 static bool pirq_needs_eoi(unsigned irq)
 254 {
 255         struct irq_info *info = info_for_irq(irq);
 256
 257         BUG_ON(info->type != IRQT_PIRQ);
 258
 259         return info->u.pirq.flags & PIRQ_NEEDS_EOI;
 260 }
 261
 262 static inline unsigned long active_evtchns(unsigned int cpu,
 263                                            struct shared_info *sh,
 264                                            unsigned int idx)
 265 {
 266         return (sh->evtchn_pending[idx] &
 267                 cpu_evtchn_mask(cpu)[idx] &
 268                 ~sh->evtchn_mask[idx]);
 269 }
 270
 271 static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
 272 {
 273         int irq = evtchn_to_irq[chn];
 274
 275         BUG_ON(irq == -1);
 276 #ifdef CONFIG_SMP
 277         cpumask_copy(irq_to_desc(irq)->affinity, cpumask_of(cpu));
 278 #endif
 279
 280         __clear_bit(chn, cpu_evtchn_mask(cpu_from_irq(irq)));
 281         __set_bit(chn, cpu_evtchn_mask(cpu));
 282
 283         irq_info[irq].cpu = cpu;
 284 }
 285
 286 static void init_evtchn_cpu_bindings(void)
 287 {
 288 #ifdef CONFIG_SMP
 289         struct irq_desc *desc;
 290         int i;
 291
 292         /* By default all event channels notify CPU#0. */
 293         for_each_irq_desc(i, desc) {
 294                 cpumask_copy(desc->affinity, cpumask_of(0));
 295         }
 296 #endif
 297
 298         memset(cpu_evtchn_mask(0), ~0, sizeof(cpu_evtchn_mask(0)));
 299 }
 300
 301 static inline void clear_evtchn(int port)
 302 {
 303         struct shared_info *s = HYPERVISOR_shared_info;
 304         sync_clear_bit(port, &s->evtchn_pending[0]);
 305 }
 306
 307 static inline void set_evtchn(int port)
 308 {
 309         struct shared_info *s = HYPERVISOR_shared_info;
 310         sync_set_bit(port, &s->evtchn_pending[0]);
 311 }
 312
 313 static inline int test_evtchn(int port)
 314 {
 315         struct shared_info *s = HYPERVISOR_shared_info;
 316         return sync_test_bit(port, &s->evtchn_pending[0]);
 317 }
 318
 319
 320 /**
 321  * notify_remote_via_irq - send event to remote end of event channel via irq
 322  * @irq: irq of event channel to send event to
 323  *
 324  * Unlike notify_remote_via_evtchn(), this is safe to use across
 325  * save/restore. Notifications on a broken connection are silently
 326  * dropped.
 327  */
 328 void notify_remote_via_irq(int irq)
 329 {
 330         int evtchn = evtchn_from_irq(irq);
 331
 332         if (VALID_EVTCHN(evtchn))
 333                 notify_remote_via_evtchn(evtchn);
 334 }
 335 EXPORT_SYMBOL_GPL(notify_remote_via_irq);
 336
 337 static void mask_evtchn(int port)
 338 {
 339         struct shared_info *s = HYPERVISOR_shared_info;
 340         sync_set_bit(port, &s->evtchn_mask[0]);
 341 }
 342
 343 static void unmask_evtchn(int port)
 344 {
 345         struct shared_info *s = HYPERVISOR_shared_info;
 346         unsigned int cpu = get_cpu();
 347
 348         BUG_ON(!irqs_disabled());
 349
 350         /* Slow path (hypercall) if this is a non-local port. */
 351         if (unlikely(cpu != cpu_from_evtchn(port))) {
 352                 struct evtchn_unmask unmask = { .port = port };
 353                 (void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask);
 354         } else {
 355                 struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
 356
 357                 sync_clear_bit(port, &s->evtchn_mask[0]);
 358
 359                 /*
 360                  * The following is basically the equivalent of
 361                  * 'hw_resend_irq'. Just like a real IO-APIC we 'lose
 362                  * the interrupt edge' if the channel is masked.
 363                  */
 364                 if (sync_test_bit(port, &s->evtchn_pending[0]) &&
 365                     !sync_test_and_set_bit(port / BITS_PER_LONG,
 366                                            &vcpu_info->evtchn_pending_sel))
 367                         vcpu_info->evtchn_upcall_pending = 1;
 368         }
 369
 370         put_cpu();
 371 }
 372
 373 static int get_nr_hw_irqs(void)
 374 {
 375         int ret = 1;
 376
 377 #ifdef CONFIG_X86_IO_APIC
 378         ret = get_nr_irqs_gsi();
 379 #endif
 380
 381         return ret;
 382 }
 383
 384 /* callers of this function should make sure that PHYSDEVOP_get_nr_pirqs
 385  * succeeded otherwise nr_pirqs won't hold the right value */
 386 static int find_unbound_pirq(void)
 387 {
 388         int i;
 389         for (i = nr_pirqs-1; i >= 0; i--) {
 390                 if (pirq_to_irq[i] < 0)
 391                         return i;
 392         }
 393         return -1;
 394 }
 395
 396 static int find_unbound_irq(void)
 397 {
 398         struct irq_data *data;
 399         int irq, res;
 400         int start = get_nr_hw_irqs();
 401
 402         if (start == nr_irqs)
 403                 goto no_irqs;
 404
 405         /* nr_irqs is a magic value. Must not use it.*/
 406         for (irq = nr_irqs-1; irq > start; irq--) {
 407                 data = irq_get_irq_data(irq);
 408                 /* only 0->15 have init'd desc; handle irq > 16 */
 409                 if (!data)
 410                         break;
 411                 if (data->chip == &no_irq_chip)
 412                         break;
 413                 if (data->chip != &xen_dynamic_chip)
 414                         continue;
 415                 if (irq_info[irq].type == IRQT_UNBOUND)
 416                         return irq;
 417         }
 418
 419         if (irq == start)
 420                 goto no_irqs;
 421
 422         res = irq_alloc_desc_at(irq, 0);
 423
 424         if (WARN_ON(res != irq))
 425                 return -1;
 426
 427         return irq;
 428
 429 no_irqs:
 430         panic("No available IRQ to bind to: increase nr_irqs!\n");
 431 }
 432
 433 static bool identity_mapped_irq(unsigned irq)
 434 {
 435         /* identity map all the hardware irqs */
 436         return irq < get_nr_hw_irqs();
 437 }
 438
 439 static void pirq_unmask_notify(int irq)
 440 {
 441         struct physdev_eoi eoi = { .irq = pirq_from_irq(irq) };
 442
 443         if (unlikely(pirq_needs_eoi(irq))) {
 444                 int rc = HYPERVISOR_physdev_op(PHYSDEVOP_eoi, &eoi);
 445                 WARN_ON(rc);
 446         }
 447 }
 448
 449 static void pirq_query_unmask(int irq)
 450 {
 451         struct physdev_irq_status_query irq_status;
 452         struct irq_info *info = info_for_irq(irq);
 453
 454         BUG_ON(info->type != IRQT_PIRQ);
 455
 456         irq_status.irq = pirq_from_irq(irq);
 457         if (HYPERVISOR_physdev_op(PHYSDEVOP_irq_status_query, &irq_status))
 458                 irq_status.flags = 0;
 459
 460         info->u.pirq.flags &= ~PIRQ_NEEDS_EOI;
 461         if (irq_status.flags & XENIRQSTAT_needs_eoi)
 462                 info->u.pirq.flags |= PIRQ_NEEDS_EOI;
 463 }
 464
 465 static bool probing_irq(int irq)
 466 {
 467         struct irq_desc *desc = irq_to_desc(irq);
 468
 469         return desc && desc->action == NULL;
 470 }
 471
 472 static unsigned int startup_pirq(unsigned int irq)
 473 {
 474         struct evtchn_bind_pirq bind_pirq;
 475         struct irq_info *info = info_for_irq(irq);
 476         int evtchn = evtchn_from_irq(irq);
 477         int rc;
 478
 479         BUG_ON(info->type != IRQT_PIRQ);
 480
 481         if (VALID_EVTCHN(evtchn))
 482                 goto out;
 483
 484         bind_pirq.pirq = pirq_from_irq(irq);
 485         /* NB. We are happy to share unless we are probing. */
 486         bind_pirq.flags = info->u.pirq.flags & PIRQ_SHAREABLE ?
 487                                         BIND_PIRQ__WILL_SHARE : 0;
 488         rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_pirq, &bind_pirq);
 489         if (rc != 0) {
 490                 if (!probing_irq(irq))
 491                         printk(KERN_INFO "Failed to obtain physical IRQ %d\n",
 492                                irq);
 493                 return 0;
 494         }
 495         evtchn = bind_pirq.port;
 496
 497         pirq_query_unmask(irq);
 498
 499         evtchn_to_irq[evtchn] = irq;
 500         bind_evtchn_to_cpu(evtchn, 0);
 501         info->evtchn = evtchn;
 502
 503 out:
 504         unmask_evtchn(evtchn);
 505         pirq_unmask_notify(irq);
 506
 507         return 0;
 508 }
 509
 510 static void shutdown_pirq(unsigned int irq)
 511 {
 512         struct evtchn_close close;
 513         struct irq_info *info = info_for_irq(irq);
 514         int evtchn = evtchn_from_irq(irq);
 515
 516         BUG_ON(info->type != IRQT_PIRQ);
 517
 518         if (!VALID_EVTCHN(evtchn))
 519                 return;
 520
 521         mask_evtchn(evtchn);
 522
 523         close.port = evtchn;
 524         if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
 525                 BUG();
 526
 527         bind_evtchn_to_cpu(evtchn, 0);
 528         evtchn_to_irq[evtchn] = -1;
 529         info->evtchn = 0;
 530 }
 531
 532 static void enable_pirq(unsigned int irq)
 533 {
 534         startup_pirq(irq);
 535 }
 536
 537 static void disable_pirq(unsigned int irq)
 538 {
 539 }
 540
 541 static void ack_pirq(unsigned int irq)
 542 {
 543         int evtchn = evtchn_from_irq(irq);
 544
 545         move_native_irq(irq);
 546
 547         if (VALID_EVTCHN(evtchn)) {
 548                 mask_evtchn(evtchn);
 549                 clear_evtchn(evtchn);
 550         }
 551 }
 552
 553 static void end_pirq(unsigned int irq)
 554 {
 555         int evtchn = evtchn_from_irq(irq);
 556         struct irq_desc *desc = irq_to_desc(irq);
 557
 558         if (WARN_ON(!desc))
 559                 return;
 560
 561         if ((desc->status & (IRQ_DISABLED|IRQ_PENDING)) ==
 562             (IRQ_DISABLED|IRQ_PENDING)) {
 563                 shutdown_pirq(irq);
 564         } else if (VALID_EVTCHN(evtchn)) {
 565                 unmask_evtchn(evtchn);
 566                 pirq_unmask_notify(irq);
 567         }
 568 }
 569
 570 static int find_irq_by_gsi(unsigned gsi)
 571 {
 572         int irq;
 573
 574         for (irq = 0; irq < nr_irqs; irq++) {
 575                 struct irq_info *info = info_for_irq(irq);
 576
 577                 if (info == NULL || info->type != IRQT_PIRQ)
 578                         continue;
 579
 580                 if (gsi_from_irq(irq) == gsi)
 581                         return irq;
 582         }
 583
 584         return -1;
 585 }
 586
 587 int xen_allocate_pirq(unsigned gsi, int shareable, char *name)
 588 {
 589         return xen_map_pirq_gsi(gsi, gsi, shareable, name);
 590 }
 591
 592 /* xen_map_pirq_gsi might allocate irqs from the top down, as a
 593  * consequence don't assume that the irq number returned has a low value
 594  * or can be used as a pirq number unless you know otherwise.
 595  *
 596  * One notable exception is when xen_map_pirq_gsi is called passing an
 597  * hardware gsi as argument, in that case the irq number returned
 598  * matches the gsi number passed as second argument.
 599  *
 600  * Note: We don't assign an event channel until the irq actually started
 601  * up.  Return an existing irq if we've already got one for the gsi.
 602  */
 603 int xen_map_pirq_gsi(unsigned pirq, unsigned gsi, int shareable, char *name)
 604 {
 605         int irq = 0;
 606         struct physdev_irq irq_op;
 607
 608         spin_lock(&irq_mapping_update_lock);
 609
 610         if ((pirq > nr_pirqs) || (gsi > nr_irqs)) {
 611                 printk(KERN_WARNING "xen_map_pirq_gsi: %s %s is incorrect!\n",
 612                         pirq > nr_pirqs ? "nr_pirqs" :"",
 613                         gsi > nr_irqs ? "nr_irqs" : "");
 614                 goto out;
 615         }
 616
 617         irq = find_irq_by_gsi(gsi);
 618         if (irq != -1) {
 619                 printk(KERN_INFO "xen_map_pirq_gsi: returning irq %d for gsi %u\n",
 620                        irq, gsi);
 621                 goto out;       /* XXX need refcount? */
 622         }
 623
 624         /* If we are a PV guest, we don't have GSIs (no ACPI passed). Therefore
 625          * we are using the !xen_initial_domain() to drop in the function.*/
 626         if (identity_mapped_irq(gsi) || !xen_initial_domain()) {
 627                 irq = gsi;
 628                 irq_alloc_desc_at(irq, 0);
 629         } else
 630                 irq = find_unbound_irq();
 631
 632         set_irq_chip_and_handler_name(irq, &xen_pirq_chip,
 633                                       handle_level_irq, name);
 634
 635         irq_op.irq = irq;
 636         irq_op.vector = 0;
 637
 638         /* Only the privileged domain can do this. For non-priv, the pcifront
 639          * driver provides a PCI bus that does the call to do exactly
 640          * this in the priv domain. */
 641         if (xen_initial_domain() &&
 642             HYPERVISOR_physdev_op(PHYSDEVOP_alloc_irq_vector, &irq_op)) {
 643                 irq_free_desc(irq);
 644                 irq = -ENOSPC;
 645                 goto out;
 646         }
 647
 648         irq_info[irq] = mk_pirq_info(0, pirq, gsi, irq_op.vector);
 649         irq_info[irq].u.pirq.flags |= shareable ? PIRQ_SHAREABLE : 0;
 650         pirq_to_irq[pirq] = irq;
 651
 652 out:
 653         spin_unlock(&irq_mapping_update_lock);
 654
 655         return irq;
 656 }
 657
 658 int xen_destroy_irq(int irq)
 659 {
 660         struct irq_desc *desc;
 661         int rc = -ENOENT;
 662
 663         spin_lock(&irq_mapping_update_lock);
 664
 665         desc = irq_to_desc(irq);
 666         if (!desc)
 667                 goto out;
 668
 669         irq_info[irq] = mk_unbound_info();
 670
 671         irq_free_desc(irq);
 672
 673 out:
 674         spin_unlock(&irq_mapping_update_lock);
 675         return rc;
 676 }
 677
 678 int xen_vector_from_irq(unsigned irq)
 679 {
 680         return vector_from_irq(irq);
 681 }
 682
 683 int xen_gsi_from_irq(unsigned irq)
 684 {
 685         return gsi_from_irq(irq);
 686 }
 687
 688 int bind_evtchn_to_irq(unsigned int evtchn)
 689 {
 690         int irq;
 691
 692         spin_lock(&irq_mapping_update_lock);
 693
 694         irq = evtchn_to_irq[evtchn];
 695
 696         if (irq == -1) {
 697                 irq = find_unbound_irq();
 698
 699                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 700                                               handle_edge_irq, "event");
 701
 702                 evtchn_to_irq[evtchn] = irq;
 703                 irq_info[irq] = mk_evtchn_info(evtchn);
 704         }
 705
 706         spin_unlock(&irq_mapping_update_lock);
 707
 708         return irq;
 709 }
 710 EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);
 711
 712 static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
 713 {
 714         struct evtchn_bind_ipi bind_ipi;
 715         int evtchn, irq;
 716
 717         spin_lock(&irq_mapping_update_lock);
 718
 719         irq = per_cpu(ipi_to_irq, cpu)[ipi];
 720
 721         if (irq == -1) {
 722                 irq = find_unbound_irq();
 723                 if (irq < 0)
 724                         goto out;
 725
 726                 set_irq_chip_and_handler_name(irq, &xen_percpu_chip,
 727                                               handle_percpu_irq, "ipi");
 728
 729                 bind_ipi.vcpu = cpu;
 730                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
 731                                                 &bind_ipi) != 0)
 732                         BUG();
 733                 evtchn = bind_ipi.port;
 734
 735                 evtchn_to_irq[evtchn] = irq;
 736                 irq_info[irq] = mk_ipi_info(evtchn, ipi);
 737                 per_cpu(ipi_to_irq, cpu)[ipi] = irq;
 738
 739                 bind_evtchn_to_cpu(evtchn, cpu);
 740         }
 741
 742  out:
 743         spin_unlock(&irq_mapping_update_lock);
 744         return irq;
 745 }
 746
 747
 748 static int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 749 {
 750         struct evtchn_bind_virq bind_virq;
 751         int evtchn, irq;
 752
 753         spin_lock(&irq_mapping_update_lock);
 754
 755         irq = per_cpu(virq_to_irq, cpu)[virq];
 756
 757         if (irq == -1) {
 758                 bind_virq.virq = virq;
 759                 bind_virq.vcpu = cpu;
 760                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
 761                                                 &bind_virq) != 0)
 762                         BUG();
 763                 evtchn = bind_virq.port;
 764
 765                 irq = find_unbound_irq();
 766
 767                 set_irq_chip_and_handler_name(irq, &xen_percpu_chip,
 768                                               handle_percpu_irq, "virq");
 769
 770                 evtchn_to_irq[evtchn] = irq;
 771                 irq_info[irq] = mk_virq_info(evtchn, virq);
 772
 773                 per_cpu(virq_to_irq, cpu)[virq] = irq;
 774
 775                 bind_evtchn_to_cpu(evtchn, cpu);
 776         }
 777
 778         spin_unlock(&irq_mapping_update_lock);
 779
 780         return irq;
 781 }
 782
 783 static void unbind_from_irq(unsigned int irq)
 784 {
 785         struct evtchn_close close;
 786         int evtchn = evtchn_from_irq(irq);
 787
 788         spin_lock(&irq_mapping_update_lock);
 789
 790         if (VALID_EVTCHN(evtchn)) {
 791                 close.port = evtchn;
 792                 if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
 793                         BUG();
 794
 795                 switch (type_from_irq(irq)) {
 796                 case IRQT_VIRQ:
 797                         per_cpu(virq_to_irq, cpu_from_evtchn(evtchn))
 798                                 [virq_from_irq(irq)] = -1;
 799                         break;
 800                 case IRQT_IPI:
 801                         per_cpu(ipi_to_irq, cpu_from_evtchn(evtchn))
 802                                 [ipi_from_irq(irq)] = -1;
 803                         break;
 804                 default:
 805                         break;
 806                 }
 807
 808                 /* Closed ports are implicitly re-bound to VCPU0. */
 809                 bind_evtchn_to_cpu(evtchn, 0);
 810
 811                 evtchn_to_irq[evtchn] = -1;
 812         }
 813
 814         if (irq_info[irq].type != IRQT_UNBOUND) {
 815                 irq_info[irq] = mk_unbound_info();
 816
 817                 irq_free_desc(irq);
 818         }
 819
 820         spin_unlock(&irq_mapping_update_lock);
 821 }
 822
 823 int bind_evtchn_to_irqhandler(unsigned int evtchn,
 824                               irq_handler_t handler,
 825                               unsigned long irqflags,
 826                               const char *devname, void *dev_id)
 827 {
 828         unsigned int irq;
 829         int retval;
 830
 831         irq = bind_evtchn_to_irq(evtchn);
 832         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 833         if (retval != 0) {
 834                 unbind_from_irq(irq);
 835                 return retval;
 836         }
 837
 838         return irq;
 839 }
 840 EXPORT_SYMBOL_GPL(bind_evtchn_to_irqhandler);
 841
 842 int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
 843                             irq_handler_t handler,
 844                             unsigned long irqflags, const char *devname, void *dev_id)
 845 {
 846         unsigned int irq;
 847         int retval;
 848
 849         irq = bind_virq_to_irq(virq, cpu);
 850         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 851         if (retval != 0) {
 852                 unbind_from_irq(irq);
 853                 return retval;
 854         }
 855
 856         return irq;
 857 }
 858 EXPORT_SYMBOL_GPL(bind_virq_to_irqhandler);
 859
 860 int bind_ipi_to_irqhandler(enum ipi_vector ipi,
 861                            unsigned int cpu,
 862                            irq_handler_t handler,
 863                            unsigned long irqflags,
 864                            const char *devname,
 865                            void *dev_id)
 866 {
 867         int irq, retval;
 868
 869         irq = bind_ipi_to_irq(ipi, cpu);
 870         if (irq < 0)
 871                 return irq;
 872
 873         irqflags |= IRQF_NO_SUSPEND;
 874         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 875         if (retval != 0) {
 876                 unbind_from_irq(irq);
 877                 return retval;
 878         }
 879
 880         return irq;
 881 }
 882
 883 void unbind_from_irqhandler(unsigned int irq, void *dev_id)
 884 {
 885         free_irq(irq, dev_id);
 886         unbind_from_irq(irq);
 887 }
 888 EXPORT_SYMBOL_GPL(unbind_from_irqhandler);
 889
 890 void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
 891 {
 892         int irq = per_cpu(ipi_to_irq, cpu)[vector];
 893         BUG_ON(irq < 0);
 894         notify_remote_via_irq(irq);
 895 }
 896
 897 irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 898 {
 899         struct shared_info *sh = HYPERVISOR_shared_info;
 900         int cpu = smp_processor_id();
 901         int i;
 902         unsigned long flags;
 903         static DEFINE_SPINLOCK(debug_lock);
 904
 905         spin_lock_irqsave(&debug_lock, flags);
 906
 907         printk("vcpu %d\n  ", cpu);
 908
 909         for_each_online_cpu(i) {
 910                 struct vcpu_info *v = per_cpu(xen_vcpu, i);
 911                 printk("%d: masked=%d pending=%d event_sel %08lx\n  ", i,
 912                         (get_irq_regs() && i == cpu) ? xen_irqs_disabled(get_irq_regs()) : v->evtchn_upcall_mask,
 913                         v->evtchn_upcall_pending,
 914                         v->evtchn_pending_sel);
 915         }
 916         printk("pending:\n   ");
 917         for(i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--)
 918                 printk("%08lx%s", sh->evtchn_pending[i],
 919                         i % 8 == 0 ? "\n   " : " ");
 920         printk("\nmasks:\n   ");
 921         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
 922                 printk("%08lx%s", sh->evtchn_mask[i],
 923                         i % 8 == 0 ? "\n   " : " ");
 924
 925         printk("\nunmasked:\n   ");
 926         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
 927                 printk("%08lx%s", sh->evtchn_pending[i] & ~sh->evtchn_mask[i],
 928                         i % 8 == 0 ? "\n   " : " ");
 929
 930         printk("\npending list:\n");
 931         for(i = 0; i < NR_EVENT_CHANNELS; i++) {
 932                 if (sync_test_bit(i, sh->evtchn_pending)) {
 933                         printk("  %d: event %d -> irq %d\n",
 934                                cpu_from_evtchn(i), i,
 935                                evtchn_to_irq[i]);
 936                 }
 937         }
 938
 939         spin_unlock_irqrestore(&debug_lock, flags);
 940
 941         return IRQ_HANDLED;
 942 }
 943
 944 static DEFINE_PER_CPU(unsigned, xed_nesting_count);
 945
 946 /*
 947  * Search the CPUs pending events bitmasks.  For each one found, map
 948  * the event number to an irq, and feed it into do_IRQ() for
 949  * handling.
 950  *
 951  * Xen uses a two-level bitmap to speed searching.  The first level is
 952  * a bitset of words which contain pending event bits.  The second
 953  * level is a bitset of pending events themselves.
 954  */
 955 static void __xen_evtchn_do_upcall(void)
 956 {
 957         int cpu = get_cpu();
 958         struct shared_info *s = HYPERVISOR_shared_info;
 959         struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
 960         unsigned count;
 961
 962         do {
 963                 unsigned long pending_words;
 964
 965                 vcpu_info->evtchn_upcall_pending = 0;
 966
 967                 if (__get_cpu_var(xed_nesting_count)++)
 968                         goto out;
 969
 970 #ifndef CONFIG_X86 /* No need for a barrier -- XCHG is a barrier on x86. */
 971                 /* Clear master flag /before/ clearing selector flag. */
 972                 wmb();
 973 #endif
 974                 pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
 975                 while (pending_words != 0) {
 976                         unsigned long pending_bits;
 977                         int word_idx = __ffs(pending_words);
 978                         pending_words &= ~(1UL << word_idx);
 979
 980                         while ((pending_bits = active_evtchns(cpu, s, word_idx)) != 0) {
 981                                 int bit_idx = __ffs(pending_bits);
 982                                 int port = (word_idx * BITS_PER_LONG) + bit_idx;
 983                                 int irq = evtchn_to_irq[port];
 984                                 struct irq_desc *desc;
 985
 986                                 if (irq != -1) {
 987                                         desc = irq_to_desc(irq);
 988                                         if (desc)
 989                                                 generic_handle_irq_desc(irq, desc);
 990                                 }
 991                         }
 992                 }
 993
 994                 BUG_ON(!irqs_disabled());
 995
 996                 count = __get_cpu_var(xed_nesting_count);
 997                 __get_cpu_var(xed_nesting_count) = 0;
 998         } while (count != 1 || vcpu_info->evtchn_upcall_pending);
 999
1000 out:
1001
1002         put_cpu();
1003 }
1004
1005 void xen_evtchn_do_upcall(struct pt_regs *regs)
1006 {
1007         struct pt_regs *old_regs = set_irq_regs(regs);
1008
1009         exit_idle();
1010         irq_enter();
1011
1012         __xen_evtchn_do_upcall();
1013
1014         irq_exit();
1015         set_irq_regs(old_regs);
1016 }
1017
1018 void xen_hvm_evtchn_do_upcall(void)
1019 {
1020         __xen_evtchn_do_upcall();
1021 }
1022 EXPORT_SYMBOL_GPL(xen_hvm_evtchn_do_upcall);
1023
1024 /* Rebind a new event channel to an existing irq. */
1025 void rebind_evtchn_irq(int evtchn, int irq)
1026 {
1027         struct irq_info *info = info_for_irq(irq);
1028
1029         /* Make sure the irq is masked, since the new event channel
1030            will also be masked. */
1031         disable_irq(irq);
1032
1033         spin_lock(&irq_mapping_update_lock);
1034
1035         /* After resume the irq<->evtchn mappings are all cleared out */
1036         BUG_ON(evtchn_to_irq[evtchn] != -1);
1037         /* Expect irq to have been bound before,
1038            so there should be a proper type */
1039         BUG_ON(info->type == IRQT_UNBOUND);
1040
1041         evtchn_to_irq[evtchn] = irq;
1042         irq_info[irq] = mk_evtchn_info(evtchn);
1043
1044         spin_unlock(&irq_mapping_update_lock);
1045
1046         /* new event channels are always bound to cpu 0 */
1047         irq_set_affinity(irq, cpumask_of(0));
1048
1049         /* Unmask the event channel. */
1050         enable_irq(irq);
1051 }
1052
1053 /* Rebind an evtchn so that it gets delivered to a specific cpu */
1054 static int rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
1055 {
1056         struct evtchn_bind_vcpu bind_vcpu;
1057         int evtchn = evtchn_from_irq(irq);
1058
1059         /* events delivered via platform PCI interrupts are always
1060          * routed to vcpu 0 */
1061         if (!VALID_EVTCHN(evtchn) ||
1062                 (xen_hvm_domain() && !xen_have_vector_callback))
1063                 return -1;
1064
1065         /* Send future instances of this interrupt to other vcpu. */
1066         bind_vcpu.port = evtchn;
1067         bind_vcpu.vcpu = tcpu;
1068
1069         /*
1070          * If this fails, it usually just indicates that we're dealing with a
1071          * virq or IPI channel, which don't actually need to be rebound. Ignore
1072          * it, but don't do the xenlinux-level rebind in that case.
1073          */
1074         if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
1075                 bind_evtchn_to_cpu(evtchn, tcpu);
1076
1077         return 0;
1078 }
1079
1080 static int set_affinity_irq(unsigned irq, const struct cpumask *dest)
1081 {
1082         unsigned tcpu = cpumask_first(dest);
1083
1084         return rebind_irq_to_cpu(irq, tcpu);
1085 }
1086
1087 int resend_irq_on_evtchn(unsigned int irq)
1088 {
1089         int masked, evtchn = evtchn_from_irq(irq);
1090         struct shared_info *s = HYPERVISOR_shared_info;
1091
1092         if (!VALID_EVTCHN(evtchn))
1093                 return 1;
1094
1095         masked = sync_test_and_set_bit(evtchn, s->evtchn_mask);
1096         sync_set_bit(evtchn, s->evtchn_pending);
1097         if (!masked)
1098                 unmask_evtchn(evtchn);
1099
1100         return 1;
1101 }
1102
1103 static void enable_dynirq(unsigned int irq)
1104 {
1105         int evtchn = evtchn_from_irq(irq);
1106
1107         if (VALID_EVTCHN(evtchn))
1108                 unmask_evtchn(evtchn);
1109 }
1110
1111 static void disable_dynirq(unsigned int irq)
1112 {
1113         int evtchn = evtchn_from_irq(irq);
1114
1115         if (VALID_EVTCHN(evtchn))
1116                 mask_evtchn(evtchn);
1117 }
1118
1119 static void ack_dynirq(unsigned int irq)
1120 {
1121         int evtchn = evtchn_from_irq(irq);
1122
1123         move_native_irq(irq);
1124
1125         if (VALID_EVTCHN(evtchn))
1126                 clear_evtchn(evtchn);
1127 }
1128
1129 static int retrigger_dynirq(unsigned int irq)
1130 {
1131         int evtchn = evtchn_from_irq(irq);
1132         struct shared_info *sh = HYPERVISOR_shared_info;
1133         int ret = 0;
1134
1135         if (VALID_EVTCHN(evtchn)) {
1136                 int masked;
1137
1138                 masked = sync_test_and_set_bit(evtchn, sh->evtchn_mask);
1139                 sync_set_bit(evtchn, sh->evtchn_pending);
1140                 if (!masked)
1141                         unmask_evtchn(evtchn);
1142                 ret = 1;
1143         }
1144
1145         return ret;
1146 }
1147
1148 static void restore_cpu_virqs(unsigned int cpu)
1149 {
1150         struct evtchn_bind_virq bind_virq;
1151         int virq, irq, evtchn;
1152
1153         for (virq = 0; virq < NR_VIRQS; virq++) {
1154                 if ((irq = per_cpu(virq_to_irq, cpu)[virq]) == -1)
1155                         continue;
1156
1157                 BUG_ON(virq_from_irq(irq) != virq);
1158
1159                 /* Get a new binding from Xen. */
1160                 bind_virq.virq = virq;
1161                 bind_virq.vcpu = cpu;
1162                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
1163                                                 &bind_virq) != 0)
1164                         BUG();
1165                 evtchn = bind_virq.port;
1166
1167                 /* Record the new mapping. */
1168                 evtchn_to_irq[evtchn] = irq;
1169                 irq_info[irq] = mk_virq_info(evtchn, virq);
1170                 bind_evtchn_to_cpu(evtchn, cpu);
1171
1172                 /* Ready for use. */
1173                 unmask_evtchn(evtchn);
1174         }
1175 }
1176
1177 static void restore_cpu_ipis(unsigned int cpu)
1178 {
1179         struct evtchn_bind_ipi bind_ipi;
1180         int ipi, irq, evtchn;
1181
1182         for (ipi = 0; ipi < XEN_NR_IPIS; ipi++) {
1183                 if ((irq = per_cpu(ipi_to_irq, cpu)[ipi]) == -1)
1184                         continue;
1185
1186                 BUG_ON(ipi_from_irq(irq) != ipi);
1187
1188                 /* Get a new binding from Xen. */
1189                 bind_ipi.vcpu = cpu;
1190                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
1191                                                 &bind_ipi) != 0)
1192                         BUG();
1193                 evtchn = bind_ipi.port;
1194
1195                 /* Record the new mapping. */
1196                 evtchn_to_irq[evtchn] = irq;
1197                 irq_info[irq] = mk_ipi_info(evtchn, ipi);
1198                 bind_evtchn_to_cpu(evtchn, cpu);
1199
1200                 /* Ready for use. */
1201                 unmask_evtchn(evtchn);
1202
1203         }
1204 }
1205
1206 /* Clear an irq's pending state, in preparation for polling on it */
1207 void xen_clear_irq_pending(int irq)
1208 {
1209         int evtchn = evtchn_from_irq(irq);
1210
1211         if (VALID_EVTCHN(evtchn))
1212                 clear_evtchn(evtchn);
1213 }
1214 EXPORT_SYMBOL(xen_clear_irq_pending);
1215 void xen_set_irq_pending(int irq)
1216 {
1217         int evtchn = evtchn_from_irq(irq);
1218
1219         if (VALID_EVTCHN(evtchn))
1220                 set_evtchn(evtchn);
1221 }
1222
1223 bool xen_test_irq_pending(int irq)
1224 {
1225         int evtchn = evtchn_from_irq(irq);
1226         bool ret = false;
1227
1228         if (VALID_EVTCHN(evtchn))
1229                 ret = test_evtchn(evtchn);
1230
1231         return ret;
1232 }
1233
1234 /* Poll waiting for an irq to become pending with timeout.  In the usual case,
1235  * the irq will be disabled so it won't deliver an interrupt. */
1236 void xen_poll_irq_timeout(int irq, u64 timeout)
1237 {
1238         evtchn_port_t evtchn = evtchn_from_irq(irq);
1239
1240         if (VALID_EVTCHN(evtchn)) {
1241                 struct sched_poll poll;
1242
1243                 poll.nr_ports = 1;
1244                 poll.timeout = timeout;
1245                 set_xen_guest_handle(poll.ports, &evtchn);
1246
1247                 if (HYPERVISOR_sched_op(SCHEDOP_poll, &poll) != 0)
1248                         BUG();
1249         }
1250 }
1251 EXPORT_SYMBOL(xen_poll_irq_timeout);
1252 /* Poll waiting for an irq to become pending.  In the usual case, the
1253  * irq will be disabled so it won't deliver an interrupt. */
1254 void xen_poll_irq(int irq)
1255 {
1256         xen_poll_irq_timeout(irq, 0 /* no timeout */);
1257 }
1258
1259 void xen_irq_resume(void)
1260 {
1261         unsigned int cpu, irq, evtchn;
1262
1263         init_evtchn_cpu_bindings();
1264
1265         /* New event-channel space is not 'live' yet. */
1266         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
1267                 mask_evtchn(evtchn);
1268
1269         /* No IRQ <-> event-channel mappings. */
1270         for (irq = 0; irq < nr_irqs; irq++)
1271                 irq_info[irq].evtchn = 0; /* zap event-channel binding */
1272
1273         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
1274                 evtchn_to_irq[evtchn] = -1;
1275
1276         for_each_possible_cpu(cpu) {
1277                 restore_cpu_virqs(cpu);
1278                 restore_cpu_ipis(cpu);
1279         }
1280 }
1281
1282 static struct irq_chip xen_dynamic_chip __read_mostly = {
1283         .name           = "xen-dyn",
1284
1285         .disable        = disable_dynirq,
1286         .mask           = disable_dynirq,
1287         .unmask         = enable_dynirq,
1288
1289         .ack            = ack_dynirq,
1290         .set_affinity   = set_affinity_irq,
1291         .retrigger      = retrigger_dynirq,
1292 };
1293
1294 static struct irq_chip xen_pirq_chip __read_mostly = {
1295         .name           = "xen-pirq",
1296
1297         .startup        = startup_pirq,
1298         .shutdown       = shutdown_pirq,
1299
1300         .enable         = enable_pirq,
1301         .unmask         = enable_pirq,
1302
1303         .disable        = disable_pirq,
1304         .mask           = disable_pirq,
1305
1306         .ack            = ack_pirq,
1307         .end            = end_pirq,
1308
1309         .set_affinity   = set_affinity_irq,
1310
1311         .retrigger      = retrigger_dynirq,
1312 };
1313
1314 static struct irq_chip xen_percpu_chip __read_mostly = {
1315         .name           = "xen-percpu",
1316
1317         .disable        = disable_dynirq,
1318         .mask           = disable_dynirq,
1319         .unmask         = enable_dynirq,
1320
1321         .ack            = ack_dynirq,
1322 };
1323
1324 int xen_set_callback_via(uint64_t via)
1325 {
1326         struct xen_hvm_param a;
1327         a.domid = DOMID_SELF;
1328         a.index = HVM_PARAM_CALLBACK_IRQ;
1329         a.value = via;
1330         return HYPERVISOR_hvm_op(HVMOP_set_param, &a);
1331 }
1332 EXPORT_SYMBOL_GPL(xen_set_callback_via);
1333
1334 #ifdef CONFIG_XEN_PVHVM
1335 /* Vector callbacks are better than PCI interrupts to receive event
1336  * channel notifications because we can receive vector callbacks on any
1337  * vcpu and we don't need PCI support or APIC interactions. */
1338 void xen_callback_vector(void)
1339 {
1340         int rc;
1341         uint64_t callback_via;
1342         if (xen_have_vector_callback) {
1343                 callback_via = HVM_CALLBACK_VECTOR(XEN_HVM_EVTCHN_CALLBACK);
1344                 rc = xen_set_callback_via(callback_via);
1345                 if (rc) {
1346                         printk(KERN_ERR "Request for Xen HVM callback vector"
1347                                         " failed.\n");
1348                         xen_have_vector_callback = 0;
1349                         return;
1350                 }
1351                 printk(KERN_INFO "Xen HVM callback vector for event delivery is "
1352                                 "enabled\n");
1353                 /* in the restore case the vector has already been allocated */
1354                 if (!test_bit(XEN_HVM_EVTCHN_CALLBACK, used_vectors))
1355                         alloc_intr_gate(XEN_HVM_EVTCHN_CALLBACK, xen_hvm_callback_vector);
1356         }
1357 }
1358 #else
1359 void xen_callback_vector(void) {}
1360 #endif
1361
1362 void __init xen_init_IRQ(void)
1363 {
1364         int i, rc;
1365         struct physdev_nr_pirqs op_nr_pirqs;
1366
1367         cpu_evtchn_mask_p = kcalloc(nr_cpu_ids, sizeof(struct cpu_evtchn_s),
1368                                     GFP_KERNEL);
1369         irq_info = kcalloc(nr_irqs, sizeof(*irq_info), GFP_KERNEL);
1370
1371         rc = HYPERVISOR_physdev_op(PHYSDEVOP_get_nr_pirqs, &op_nr_pirqs);
1372         if (rc < 0) {
1373                 nr_pirqs = nr_irqs;
1374                 if (rc != -ENOSYS)
1375                         printk(KERN_WARNING "PHYSDEVOP_get_nr_pirqs returned rc=%d\n", rc);
1376         } else {
1377                 if (xen_pv_domain() && !xen_initial_domain())
1378                         nr_pirqs = max((int)op_nr_pirqs.nr_pirqs, nr_irqs);
1379                 else
1380                         nr_pirqs = op_nr_pirqs.nr_pirqs;
1381         }
1382         pirq_to_irq = kcalloc(nr_pirqs, sizeof(*pirq_to_irq), GFP_KERNEL);
1383         for (i = 0; i < nr_pirqs; i++)
1384                 pirq_to_irq[i] = -1;
1385
1386         evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
1387                                     GFP_KERNEL);
1388         for (i = 0; i < NR_EVENT_CHANNELS; i++)
1389                 evtchn_to_irq[i] = -1;
1390
1391         init_evtchn_cpu_bindings();
1392
1393         /* No event channels are 'live' right now. */
1394         for (i = 0; i < NR_EVENT_CHANNELS; i++)
1395                 mask_evtchn(i);
1396
1397         if (xen_hvm_domain()) {
1398                 xen_callback_vector();
1399                 native_init_IRQ();
1400         } else {
1401                 irq_ctx_init(smp_processor_id());
1402         }
1403 }