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                                 xen_pv_domain())) {
 628                 irq = gsi;
 629                 irq_alloc_desc_at(irq, 0);
 630         } else
 631                 irq = find_unbound_irq();
 632
 633         set_irq_chip_and_handler_name(irq, &xen_pirq_chip,
 634                                       handle_level_irq, name);
 635
 636         irq_op.irq = irq;
 637         irq_op.vector = 0;
 638
 639         /* Only the privileged domain can do this. For non-priv, the pcifront
 640          * driver provides a PCI bus that does the call to do exactly
 641          * this in the priv domain. */
 642         if (xen_initial_domain() &&
 643             HYPERVISOR_physdev_op(PHYSDEVOP_alloc_irq_vector, &irq_op)) {
 644                 irq_free_desc(irq);
 645                 irq = -ENOSPC;
 646                 goto out;
 647         }
 648
 649         irq_info[irq] = mk_pirq_info(0, pirq, gsi, irq_op.vector);
 650         irq_info[irq].u.pirq.flags |= shareable ? PIRQ_SHAREABLE : 0;
 651         pirq_to_irq[pirq] = irq;
 652
 653 out:
 654         spin_unlock(&irq_mapping_update_lock);
 655
 656         return irq;
 657 }
 658
 659 void xen_allocate_pirq_msi(char *name, int *irq, int *pirq)
 660 {
 661         spin_lock(&irq_mapping_update_lock);
 662
 663         *irq = find_unbound_irq();
 664         if (*irq == -1)
 665                 goto out;
 666
 667         *pirq = find_unbound_pirq();
 668         if (*pirq == -1)
 669                 goto out;
 670
 671         set_irq_chip_and_handler_name(*irq, &xen_pirq_chip,
 672                                       handle_level_irq, name);
 673
 674         irq_info[*irq] = mk_pirq_info(0, *pirq, 0, 0);
 675         pirq_to_irq[*pirq] = *irq;
 676
 677 out:
 678         spin_unlock(&irq_mapping_update_lock);
 679 }
 680
 681 int xen_destroy_irq(int irq)
 682 {
 683         struct irq_desc *desc;
 684         struct physdev_unmap_pirq unmap_irq;
 685         struct irq_info *info = info_for_irq(irq);
 686         int rc = -ENOENT;
 687
 688         spin_lock(&irq_mapping_update_lock);
 689
 690         desc = irq_to_desc(irq);
 691         if (!desc)
 692                 goto out;
 693
 694         if (xen_initial_domain()) {
 695                 unmap_irq.pirq = info->u.pirq.gsi;
 696                 unmap_irq.domid = DOMID_SELF;
 697                 rc = HYPERVISOR_physdev_op(PHYSDEVOP_unmap_pirq, &unmap_irq);
 698                 if (rc) {
 699                         printk(KERN_WARNING "unmap irq failed %d\n", rc);
 700                         goto out;
 701                 }
 702         }
 703         irq_info[irq] = mk_unbound_info();
 704
 705         irq_free_desc(irq);
 706
 707 out:
 708         spin_unlock(&irq_mapping_update_lock);
 709         return rc;
 710 }
 711
 712 int xen_vector_from_irq(unsigned irq)
 713 {
 714         return vector_from_irq(irq);
 715 }
 716
 717 int xen_gsi_from_irq(unsigned irq)
 718 {
 719         return gsi_from_irq(irq);
 720 }
 721
 722 int bind_evtchn_to_irq(unsigned int evtchn)
 723 {
 724         int irq;
 725
 726         spin_lock(&irq_mapping_update_lock);
 727
 728         irq = evtchn_to_irq[evtchn];
 729
 730         if (irq == -1) {
 731                 irq = find_unbound_irq();
 732
 733                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 734                                               handle_edge_irq, "event");
 735
 736                 evtchn_to_irq[evtchn] = irq;
 737                 irq_info[irq] = mk_evtchn_info(evtchn);
 738         }
 739
 740         spin_unlock(&irq_mapping_update_lock);
 741
 742         return irq;
 743 }
 744 EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);
 745
 746 static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
 747 {
 748         struct evtchn_bind_ipi bind_ipi;
 749         int evtchn, irq;
 750
 751         spin_lock(&irq_mapping_update_lock);
 752
 753         irq = per_cpu(ipi_to_irq, cpu)[ipi];
 754
 755         if (irq == -1) {
 756                 irq = find_unbound_irq();
 757                 if (irq < 0)
 758                         goto out;
 759
 760                 set_irq_chip_and_handler_name(irq, &xen_percpu_chip,
 761                                               handle_percpu_irq, "ipi");
 762
 763                 bind_ipi.vcpu = cpu;
 764                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
 765                                                 &bind_ipi) != 0)
 766                         BUG();
 767                 evtchn = bind_ipi.port;
 768
 769                 evtchn_to_irq[evtchn] = irq;
 770                 irq_info[irq] = mk_ipi_info(evtchn, ipi);
 771                 per_cpu(ipi_to_irq, cpu)[ipi] = irq;
 772
 773                 bind_evtchn_to_cpu(evtchn, cpu);
 774         }
 775
 776  out:
 777         spin_unlock(&irq_mapping_update_lock);
 778         return irq;
 779 }
 780
 781
 782 static int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 783 {
 784         struct evtchn_bind_virq bind_virq;
 785         int evtchn, irq;
 786
 787         spin_lock(&irq_mapping_update_lock);
 788
 789         irq = per_cpu(virq_to_irq, cpu)[virq];
 790
 791         if (irq == -1) {
 792                 bind_virq.virq = virq;
 793                 bind_virq.vcpu = cpu;
 794                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
 795                                                 &bind_virq) != 0)
 796                         BUG();
 797                 evtchn = bind_virq.port;
 798
 799                 irq = find_unbound_irq();
 800
 801                 set_irq_chip_and_handler_name(irq, &xen_percpu_chip,
 802                                               handle_percpu_irq, "virq");
 803
 804                 evtchn_to_irq[evtchn] = irq;
 805                 irq_info[irq] = mk_virq_info(evtchn, virq);
 806
 807                 per_cpu(virq_to_irq, cpu)[virq] = irq;
 808
 809                 bind_evtchn_to_cpu(evtchn, cpu);
 810         }
 811
 812         spin_unlock(&irq_mapping_update_lock);
 813
 814         return irq;
 815 }
 816
 817 static void unbind_from_irq(unsigned int irq)
 818 {
 819         struct evtchn_close close;
 820         int evtchn = evtchn_from_irq(irq);
 821
 822         spin_lock(&irq_mapping_update_lock);
 823
 824         if (VALID_EVTCHN(evtchn)) {
 825                 close.port = evtchn;
 826                 if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
 827                         BUG();
 828
 829                 switch (type_from_irq(irq)) {
 830                 case IRQT_VIRQ:
 831                         per_cpu(virq_to_irq, cpu_from_evtchn(evtchn))
 832                                 [virq_from_irq(irq)] = -1;
 833                         break;
 834                 case IRQT_IPI:
 835                         per_cpu(ipi_to_irq, cpu_from_evtchn(evtchn))
 836                                 [ipi_from_irq(irq)] = -1;
 837                         break;
 838                 default:
 839                         break;
 840                 }
 841
 842                 /* Closed ports are implicitly re-bound to VCPU0. */
 843                 bind_evtchn_to_cpu(evtchn, 0);
 844
 845                 evtchn_to_irq[evtchn] = -1;
 846         }
 847
 848         if (irq_info[irq].type != IRQT_UNBOUND) {
 849                 irq_info[irq] = mk_unbound_info();
 850
 851                 irq_free_desc(irq);
 852         }
 853
 854         spin_unlock(&irq_mapping_update_lock);
 855 }
 856
 857 int bind_evtchn_to_irqhandler(unsigned int evtchn,
 858                               irq_handler_t handler,
 859                               unsigned long irqflags,
 860                               const char *devname, void *dev_id)
 861 {
 862         unsigned int irq;
 863         int retval;
 864
 865         irq = bind_evtchn_to_irq(evtchn);
 866         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 867         if (retval != 0) {
 868                 unbind_from_irq(irq);
 869                 return retval;
 870         }
 871
 872         return irq;
 873 }
 874 EXPORT_SYMBOL_GPL(bind_evtchn_to_irqhandler);
 875
 876 int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
 877                             irq_handler_t handler,
 878                             unsigned long irqflags, const char *devname, void *dev_id)
 879 {
 880         unsigned int irq;
 881         int retval;
 882
 883         irq = bind_virq_to_irq(virq, cpu);
 884         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 885         if (retval != 0) {
 886                 unbind_from_irq(irq);
 887                 return retval;
 888         }
 889
 890         return irq;
 891 }
 892 EXPORT_SYMBOL_GPL(bind_virq_to_irqhandler);
 893
 894 int bind_ipi_to_irqhandler(enum ipi_vector ipi,
 895                            unsigned int cpu,
 896                            irq_handler_t handler,
 897                            unsigned long irqflags,
 898                            const char *devname,
 899                            void *dev_id)
 900 {
 901         int irq, retval;
 902
 903         irq = bind_ipi_to_irq(ipi, cpu);
 904         if (irq < 0)
 905                 return irq;
 906
 907         irqflags |= IRQF_NO_SUSPEND;
 908         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 909         if (retval != 0) {
 910                 unbind_from_irq(irq);
 911                 return retval;
 912         }
 913
 914         return irq;
 915 }
 916
 917 void unbind_from_irqhandler(unsigned int irq, void *dev_id)
 918 {
 919         free_irq(irq, dev_id);
 920         unbind_from_irq(irq);
 921 }
 922 EXPORT_SYMBOL_GPL(unbind_from_irqhandler);
 923
 924 void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
 925 {
 926         int irq = per_cpu(ipi_to_irq, cpu)[vector];
 927         BUG_ON(irq < 0);
 928         notify_remote_via_irq(irq);
 929 }
 930
 931 irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 932 {
 933         struct shared_info *sh = HYPERVISOR_shared_info;
 934         int cpu = smp_processor_id();
 935         int i;
 936         unsigned long flags;
 937         static DEFINE_SPINLOCK(debug_lock);
 938
 939         spin_lock_irqsave(&debug_lock, flags);
 940
 941         printk("vcpu %d\n  ", cpu);
 942
 943         for_each_online_cpu(i) {
 944                 struct vcpu_info *v = per_cpu(xen_vcpu, i);
 945                 printk("%d: masked=%d pending=%d event_sel %08lx\n  ", i,
 946                         (get_irq_regs() && i == cpu) ? xen_irqs_disabled(get_irq_regs()) : v->evtchn_upcall_mask,
 947                         v->evtchn_upcall_pending,
 948                         v->evtchn_pending_sel);
 949         }
 950         printk("pending:\n   ");
 951         for(i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--)
 952                 printk("%08lx%s", sh->evtchn_pending[i],
 953                         i % 8 == 0 ? "\n   " : " ");
 954         printk("\nmasks:\n   ");
 955         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
 956                 printk("%08lx%s", sh->evtchn_mask[i],
 957                         i % 8 == 0 ? "\n   " : " ");
 958
 959         printk("\nunmasked:\n   ");
 960         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
 961                 printk("%08lx%s", sh->evtchn_pending[i] & ~sh->evtchn_mask[i],
 962                         i % 8 == 0 ? "\n   " : " ");
 963
 964         printk("\npending list:\n");
 965         for(i = 0; i < NR_EVENT_CHANNELS; i++) {
 966                 if (sync_test_bit(i, sh->evtchn_pending)) {
 967                         printk("  %d: event %d -> irq %d\n",
 968                                cpu_from_evtchn(i), i,
 969                                evtchn_to_irq[i]);
 970                 }
 971         }
 972
 973         spin_unlock_irqrestore(&debug_lock, flags);
 974
 975         return IRQ_HANDLED;
 976 }
 977
 978 static DEFINE_PER_CPU(unsigned, xed_nesting_count);
 979
 980 /*
 981  * Search the CPUs pending events bitmasks.  For each one found, map
 982  * the event number to an irq, and feed it into do_IRQ() for
 983  * handling.
 984  *
 985  * Xen uses a two-level bitmap to speed searching.  The first level is
 986  * a bitset of words which contain pending event bits.  The second
 987  * level is a bitset of pending events themselves.
 988  */
 989 static void __xen_evtchn_do_upcall(void)
 990 {
 991         int cpu = get_cpu();
 992         struct shared_info *s = HYPERVISOR_shared_info;
 993         struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
 994         unsigned count;
 995
 996         do {
 997                 unsigned long pending_words;
 998
 999                 vcpu_info->evtchn_upcall_pending = 0;
1000
1001                 if (__get_cpu_var(xed_nesting_count)++)
1002                         goto out;
1003
1004 #ifndef CONFIG_X86 /* No need for a barrier -- XCHG is a barrier on x86. */
1005                 /* Clear master flag /before/ clearing selector flag. */
1006                 wmb();
1007 #endif
1008                 pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
1009                 while (pending_words != 0) {
1010                         unsigned long pending_bits;
1011                         int word_idx = __ffs(pending_words);
1012                         pending_words &= ~(1UL << word_idx);
1013
1014                         while ((pending_bits = active_evtchns(cpu, s, word_idx)) != 0) {
1015                                 int bit_idx = __ffs(pending_bits);
1016                                 int port = (word_idx * BITS_PER_LONG) + bit_idx;
1017                                 int irq = evtchn_to_irq[port];
1018                                 struct irq_desc *desc;
1019
1020                                 if (irq != -1) {
1021                                         desc = irq_to_desc(irq);
1022                                         if (desc)
1023                                                 generic_handle_irq_desc(irq, desc);
1024                                 }
1025                         }
1026                 }
1027
1028                 BUG_ON(!irqs_disabled());
1029
1030                 count = __get_cpu_var(xed_nesting_count);
1031                 __get_cpu_var(xed_nesting_count) = 0;
1032         } while (count != 1 || vcpu_info->evtchn_upcall_pending);
1033
1034 out:
1035
1036         put_cpu();
1037 }
1038
1039 void xen_evtchn_do_upcall(struct pt_regs *regs)
1040 {
1041         struct pt_regs *old_regs = set_irq_regs(regs);
1042
1043         exit_idle();
1044         irq_enter();
1045
1046         __xen_evtchn_do_upcall();
1047
1048         irq_exit();
1049         set_irq_regs(old_regs);
1050 }
1051
1052 void xen_hvm_evtchn_do_upcall(void)
1053 {
1054         __xen_evtchn_do_upcall();
1055 }
1056 EXPORT_SYMBOL_GPL(xen_hvm_evtchn_do_upcall);
1057
1058 /* Rebind a new event channel to an existing irq. */
1059 void rebind_evtchn_irq(int evtchn, int irq)
1060 {
1061         struct irq_info *info = info_for_irq(irq);
1062
1063         /* Make sure the irq is masked, since the new event channel
1064            will also be masked. */
1065         disable_irq(irq);
1066
1067         spin_lock(&irq_mapping_update_lock);
1068
1069         /* After resume the irq<->evtchn mappings are all cleared out */
1070         BUG_ON(evtchn_to_irq[evtchn] != -1);
1071         /* Expect irq to have been bound before,
1072            so there should be a proper type */
1073         BUG_ON(info->type == IRQT_UNBOUND);
1074
1075         evtchn_to_irq[evtchn] = irq;
1076         irq_info[irq] = mk_evtchn_info(evtchn);
1077
1078         spin_unlock(&irq_mapping_update_lock);
1079
1080         /* new event channels are always bound to cpu 0 */
1081         irq_set_affinity(irq, cpumask_of(0));
1082
1083         /* Unmask the event channel. */
1084         enable_irq(irq);
1085 }
1086
1087 /* Rebind an evtchn so that it gets delivered to a specific cpu */
1088 static int rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
1089 {
1090         struct evtchn_bind_vcpu bind_vcpu;
1091         int evtchn = evtchn_from_irq(irq);
1092
1093         /* events delivered via platform PCI interrupts are always
1094          * routed to vcpu 0 */
1095         if (!VALID_EVTCHN(evtchn) ||
1096                 (xen_hvm_domain() && !xen_have_vector_callback))
1097                 return -1;
1098
1099         /* Send future instances of this interrupt to other vcpu. */
1100         bind_vcpu.port = evtchn;
1101         bind_vcpu.vcpu = tcpu;
1102
1103         /*
1104          * If this fails, it usually just indicates that we're dealing with a
1105          * virq or IPI channel, which don't actually need to be rebound. Ignore
1106          * it, but don't do the xenlinux-level rebind in that case.
1107          */
1108         if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
1109                 bind_evtchn_to_cpu(evtchn, tcpu);
1110
1111         return 0;
1112 }
1113
1114 static int set_affinity_irq(unsigned irq, const struct cpumask *dest)
1115 {
1116         unsigned tcpu = cpumask_first(dest);
1117
1118         return rebind_irq_to_cpu(irq, tcpu);
1119 }
1120
1121 int resend_irq_on_evtchn(unsigned int irq)
1122 {
1123         int masked, evtchn = evtchn_from_irq(irq);
1124         struct shared_info *s = HYPERVISOR_shared_info;
1125
1126         if (!VALID_EVTCHN(evtchn))
1127                 return 1;
1128
1129         masked = sync_test_and_set_bit(evtchn, s->evtchn_mask);
1130         sync_set_bit(evtchn, s->evtchn_pending);
1131         if (!masked)
1132                 unmask_evtchn(evtchn);
1133
1134         return 1;
1135 }
1136
1137 static void enable_dynirq(unsigned int irq)
1138 {
1139         int evtchn = evtchn_from_irq(irq);
1140
1141         if (VALID_EVTCHN(evtchn))
1142                 unmask_evtchn(evtchn);
1143 }
1144
1145 static void disable_dynirq(unsigned int irq)
1146 {
1147         int evtchn = evtchn_from_irq(irq);
1148
1149         if (VALID_EVTCHN(evtchn))
1150                 mask_evtchn(evtchn);
1151 }
1152
1153 static void ack_dynirq(unsigned int irq)
1154 {
1155         int evtchn = evtchn_from_irq(irq);
1156
1157         move_native_irq(irq);
1158
1159         if (VALID_EVTCHN(evtchn))
1160                 clear_evtchn(evtchn);
1161 }
1162
1163 static int retrigger_dynirq(unsigned int irq)
1164 {
1165         int evtchn = evtchn_from_irq(irq);
1166         struct shared_info *sh = HYPERVISOR_shared_info;
1167         int ret = 0;
1168
1169         if (VALID_EVTCHN(evtchn)) {
1170                 int masked;
1171
1172                 masked = sync_test_and_set_bit(evtchn, sh->evtchn_mask);
1173                 sync_set_bit(evtchn, sh->evtchn_pending);
1174                 if (!masked)
1175                         unmask_evtchn(evtchn);
1176                 ret = 1;
1177         }
1178
1179         return ret;
1180 }
1181
1182 static void restore_cpu_virqs(unsigned int cpu)
1183 {
1184         struct evtchn_bind_virq bind_virq;
1185         int virq, irq, evtchn;
1186
1187         for (virq = 0; virq < NR_VIRQS; virq++) {
1188                 if ((irq = per_cpu(virq_to_irq, cpu)[virq]) == -1)
1189                         continue;
1190
1191                 BUG_ON(virq_from_irq(irq) != virq);
1192
1193                 /* Get a new binding from Xen. */
1194                 bind_virq.virq = virq;
1195                 bind_virq.vcpu = cpu;
1196                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
1197                                                 &bind_virq) != 0)
1198                         BUG();
1199                 evtchn = bind_virq.port;
1200
1201                 /* Record the new mapping. */
1202                 evtchn_to_irq[evtchn] = irq;
1203                 irq_info[irq] = mk_virq_info(evtchn, virq);
1204                 bind_evtchn_to_cpu(evtchn, cpu);
1205
1206                 /* Ready for use. */
1207                 unmask_evtchn(evtchn);
1208         }
1209 }
1210
1211 static void restore_cpu_ipis(unsigned int cpu)
1212 {
1213         struct evtchn_bind_ipi bind_ipi;
1214         int ipi, irq, evtchn;
1215
1216         for (ipi = 0; ipi < XEN_NR_IPIS; ipi++) {
1217                 if ((irq = per_cpu(ipi_to_irq, cpu)[ipi]) == -1)
1218                         continue;
1219
1220                 BUG_ON(ipi_from_irq(irq) != ipi);
1221
1222                 /* Get a new binding from Xen. */
1223                 bind_ipi.vcpu = cpu;
1224                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
1225                                                 &bind_ipi) != 0)
1226                         BUG();
1227                 evtchn = bind_ipi.port;
1228
1229                 /* Record the new mapping. */
1230                 evtchn_to_irq[evtchn] = irq;
1231                 irq_info[irq] = mk_ipi_info(evtchn, ipi);
1232                 bind_evtchn_to_cpu(evtchn, cpu);
1233
1234                 /* Ready for use. */
1235                 unmask_evtchn(evtchn);
1236
1237         }
1238 }
1239
1240 /* Clear an irq's pending state, in preparation for polling on it */
1241 void xen_clear_irq_pending(int irq)
1242 {
1243         int evtchn = evtchn_from_irq(irq);
1244
1245         if (VALID_EVTCHN(evtchn))
1246                 clear_evtchn(evtchn);
1247 }
1248 EXPORT_SYMBOL(xen_clear_irq_pending);
1249 void xen_set_irq_pending(int irq)
1250 {
1251         int evtchn = evtchn_from_irq(irq);
1252
1253         if (VALID_EVTCHN(evtchn))
1254                 set_evtchn(evtchn);
1255 }
1256
1257 bool xen_test_irq_pending(int irq)
1258 {
1259         int evtchn = evtchn_from_irq(irq);
1260         bool ret = false;
1261
1262         if (VALID_EVTCHN(evtchn))
1263                 ret = test_evtchn(evtchn);
1264
1265         return ret;
1266 }
1267
1268 /* Poll waiting for an irq to become pending with timeout.  In the usual case,
1269  * the irq will be disabled so it won't deliver an interrupt. */
1270 void xen_poll_irq_timeout(int irq, u64 timeout)
1271 {
1272         evtchn_port_t evtchn = evtchn_from_irq(irq);
1273
1274         if (VALID_EVTCHN(evtchn)) {
1275                 struct sched_poll poll;
1276
1277                 poll.nr_ports = 1;
1278                 poll.timeout = timeout;
1279                 set_xen_guest_handle(poll.ports, &evtchn);
1280
1281                 if (HYPERVISOR_sched_op(SCHEDOP_poll, &poll) != 0)
1282                         BUG();
1283         }
1284 }
1285 EXPORT_SYMBOL(xen_poll_irq_timeout);
1286 /* Poll waiting for an irq to become pending.  In the usual case, the
1287  * irq will be disabled so it won't deliver an interrupt. */
1288 void xen_poll_irq(int irq)
1289 {
1290         xen_poll_irq_timeout(irq, 0 /* no timeout */);
1291 }
1292
1293 void xen_irq_resume(void)
1294 {
1295         unsigned int cpu, irq, evtchn;
1296
1297         init_evtchn_cpu_bindings();
1298
1299         /* New event-channel space is not 'live' yet. */
1300         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
1301                 mask_evtchn(evtchn);
1302
1303         /* No IRQ <-> event-channel mappings. */
1304         for (irq = 0; irq < nr_irqs; irq++)
1305                 irq_info[irq].evtchn = 0; /* zap event-channel binding */
1306
1307         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
1308                 evtchn_to_irq[evtchn] = -1;
1309
1310         for_each_possible_cpu(cpu) {
1311                 restore_cpu_virqs(cpu);
1312                 restore_cpu_ipis(cpu);
1313         }
1314 }
1315
1316 static struct irq_chip xen_dynamic_chip __read_mostly = {
1317         .name           = "xen-dyn",
1318
1319         .disable        = disable_dynirq,
1320         .mask           = disable_dynirq,
1321         .unmask         = enable_dynirq,
1322
1323         .ack            = ack_dynirq,
1324         .set_affinity   = set_affinity_irq,
1325         .retrigger      = retrigger_dynirq,
1326 };
1327
1328 static struct irq_chip xen_pirq_chip __read_mostly = {
1329         .name           = "xen-pirq",
1330
1331         .startup        = startup_pirq,
1332         .shutdown       = shutdown_pirq,
1333
1334         .enable         = enable_pirq,
1335         .unmask         = enable_pirq,
1336
1337         .disable        = disable_pirq,
1338         .mask           = disable_pirq,
1339
1340         .ack            = ack_pirq,
1341         .end            = end_pirq,
1342
1343         .set_affinity   = set_affinity_irq,
1344
1345         .retrigger      = retrigger_dynirq,
1346 };
1347
1348 static struct irq_chip xen_percpu_chip __read_mostly = {
1349         .name           = "xen-percpu",
1350
1351         .disable        = disable_dynirq,
1352         .mask           = disable_dynirq,
1353         .unmask         = enable_dynirq,
1354
1355         .ack            = ack_dynirq,
1356 };
1357
1358 int xen_set_callback_via(uint64_t via)
1359 {
1360         struct xen_hvm_param a;
1361         a.domid = DOMID_SELF;
1362         a.index = HVM_PARAM_CALLBACK_IRQ;
1363         a.value = via;
1364         return HYPERVISOR_hvm_op(HVMOP_set_param, &a);
1365 }
1366 EXPORT_SYMBOL_GPL(xen_set_callback_via);
1367
1368 #ifdef CONFIG_XEN_PVHVM
1369 /* Vector callbacks are better than PCI interrupts to receive event
1370  * channel notifications because we can receive vector callbacks on any
1371  * vcpu and we don't need PCI support or APIC interactions. */
1372 void xen_callback_vector(void)
1373 {
1374         int rc;
1375         uint64_t callback_via;
1376         if (xen_have_vector_callback) {
1377                 callback_via = HVM_CALLBACK_VECTOR(XEN_HVM_EVTCHN_CALLBACK);
1378                 rc = xen_set_callback_via(callback_via);
1379                 if (rc) {
1380                         printk(KERN_ERR "Request for Xen HVM callback vector"
1381                                         " failed.\n");
1382                         xen_have_vector_callback = 0;
1383                         return;
1384                 }
1385                 printk(KERN_INFO "Xen HVM callback vector for event delivery is "
1386                                 "enabled\n");
1387                 /* in the restore case the vector has already been allocated */
1388                 if (!test_bit(XEN_HVM_EVTCHN_CALLBACK, used_vectors))
1389                         alloc_intr_gate(XEN_HVM_EVTCHN_CALLBACK, xen_hvm_callback_vector);
1390         }
1391 }
1392 #else
1393 void xen_callback_vector(void) {}
1394 #endif
1395
1396 void __init xen_init_IRQ(void)
1397 {
1398         int i, rc;
1399         struct physdev_nr_pirqs op_nr_pirqs;
1400
1401         cpu_evtchn_mask_p = kcalloc(nr_cpu_ids, sizeof(struct cpu_evtchn_s),
1402                                     GFP_KERNEL);
1403         irq_info = kcalloc(nr_irqs, sizeof(*irq_info), GFP_KERNEL);
1404
1405         rc = HYPERVISOR_physdev_op(PHYSDEVOP_get_nr_pirqs, &op_nr_pirqs);
1406         if (rc < 0) {
1407                 nr_pirqs = nr_irqs;
1408                 if (rc != -ENOSYS)
1409                         printk(KERN_WARNING "PHYSDEVOP_get_nr_pirqs returned rc=%d\n", rc);
1410         } else {
1411                 if (xen_pv_domain() && !xen_initial_domain())
1412                         nr_pirqs = max((int)op_nr_pirqs.nr_pirqs, nr_irqs);
1413                 else
1414                         nr_pirqs = op_nr_pirqs.nr_pirqs;
1415         }
1416         pirq_to_irq = kcalloc(nr_pirqs, sizeof(*pirq_to_irq), GFP_KERNEL);
1417         for (i = 0; i < nr_pirqs; i++)
1418                 pirq_to_irq[i] = -1;
1419
1420         evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
1421                                     GFP_KERNEL);
1422         for (i = 0; i < NR_EVENT_CHANNELS; i++)
1423                 evtchn_to_irq[i] = -1;
1424
1425         init_evtchn_cpu_bindings();
1426
1427         /* No event channels are 'live' right now. */
1428         for (i = 0; i < NR_EVENT_CHANNELS; i++)
1429                 mask_evtchn(i);
1430
1431         if (xen_hvm_domain()) {
1432                 xen_callback_vector();
1433                 native_init_IRQ();
1434                 /* pci_xen_hvm_init must be called after native_init_IRQ so that
1435                  * __acpi_register_gsi can point at the right function */
1436                 pci_xen_hvm_init();
1437         } else {
1438                 irq_ctx_init(smp_processor_id());
1439                 if (xen_initial_domain())
1440                         xen_setup_pirqs();
1441         }
1442 }