SAFE public projects git trees. - safe/jmp/linux-2.6/blob - drivers/xen/events.c

   1 /*
   2  * Xen event channels
   3  *
   4  * Xen models interrupts with abstract event channels.  Because each
   5  * domain gets 1024 event channels, but NR_IRQ is not that large, we
   6  * must dynamically map irqs<->event channels.  The event channels
   7  * interface with the rest of the kernel by defining a xen interrupt
   8  * chip.  When an event is recieved, it is mapped to an irq and sent
   9  * through the normal interrupt processing path.
  10  *
  11  * There are four kinds of events which can be mapped to an event
  12  * channel:
  13  *
  14  * 1. Inter-domain notifications.  This includes all the virtual
  15  *    device events, since they're driven by front-ends in another domain
  16  *    (typically dom0).
  17  * 2. VIRQs, typically used for timers.  These are per-cpu events.
  18  * 3. IPIs.
  19  * 4. Hardware interrupts. Not supported at present.
  20  *
  21  * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
  22  */
  23
  24 #include <linux/linkage.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/irq.h>
  27 #include <linux/module.h>
  28 #include <linux/string.h>
  29
  30 #include <asm/ptrace.h>
  31 #include <asm/irq.h>
  32 #include <asm/sync_bitops.h>
  33 #include <asm/xen/hypercall.h>
  34 #include <asm/xen/hypervisor.h>
  35
  36 #include <xen/xen-ops.h>
  37 #include <xen/events.h>
  38 #include <xen/interface/xen.h>
  39 #include <xen/interface/event_channel.h>
  40
  41 /*
  42  * This lock protects updates to the following mapping and reference-count
  43  * arrays. The lock does not need to be acquired to read the mapping tables.
  44  */
  45 static DEFINE_SPINLOCK(irq_mapping_update_lock);
  46
  47 /* IRQ <-> VIRQ mapping. */
  48 static DEFINE_PER_CPU(int, virq_to_irq[NR_VIRQS]) = {[0 ... NR_VIRQS-1] = -1};
  49
  50 /* IRQ <-> IPI mapping */
  51 static DEFINE_PER_CPU(int, ipi_to_irq[XEN_NR_IPIS]) = {[0 ... XEN_NR_IPIS-1] = -1};
  52
  53 /* Packed IRQ information: binding type, sub-type index, and event channel. */
  54 struct packed_irq
  55 {
  56         unsigned short evtchn;
  57         unsigned char index;
  58         unsigned char type;
  59 };
  60
  61 static struct packed_irq irq_info[NR_IRQS];
  62
  63 /* Binding types. */
  64 enum {
  65         IRQT_UNBOUND,
  66         IRQT_PIRQ,
  67         IRQT_VIRQ,
  68         IRQT_IPI,
  69         IRQT_EVTCHN
  70 };
  71
  72 /* Convenient shorthand for packed representation of an unbound IRQ. */
  73 #define IRQ_UNBOUND     mk_irq_info(IRQT_UNBOUND, 0, 0)
  74
  75 static int evtchn_to_irq[NR_EVENT_CHANNELS] = {
  76         [0 ... NR_EVENT_CHANNELS-1] = -1
  77 };
  78 static unsigned long cpu_evtchn_mask[NR_CPUS][NR_EVENT_CHANNELS/BITS_PER_LONG];
  79 static u8 cpu_evtchn[NR_EVENT_CHANNELS];
  80
  81 /* Reference counts for bindings to IRQs. */
  82 static int irq_bindcount[NR_IRQS];
  83
  84 /* Xen will never allocate port zero for any purpose. */
  85 #define VALID_EVTCHN(chn)       ((chn) != 0)
  86
  87 static struct irq_chip xen_dynamic_chip;
  88
  89 /* Constructor for packed IRQ information. */
  90 static inline struct packed_irq mk_irq_info(u32 type, u32 index, u32 evtchn)
  91 {
  92         return (struct packed_irq) { evtchn, index, type };
  93 }
  94
  95 /*
  96  * Accessors for packed IRQ information.
  97  */
  98 static inline unsigned int evtchn_from_irq(int irq)
  99 {
 100         return irq_info[irq].evtchn;
 101 }
 102
 103 static inline unsigned int index_from_irq(int irq)
 104 {
 105         return irq_info[irq].index;
 106 }
 107
 108 static inline unsigned int type_from_irq(int irq)
 109 {
 110         return irq_info[irq].type;
 111 }
 112
 113 static inline unsigned long active_evtchns(unsigned int cpu,
 114                                            struct shared_info *sh,
 115                                            unsigned int idx)
 116 {
 117         return (sh->evtchn_pending[idx] &
 118                 cpu_evtchn_mask[cpu][idx] &
 119                 ~sh->evtchn_mask[idx]);
 120 }
 121
 122 static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
 123 {
 124         int irq = evtchn_to_irq[chn];
 125
 126         BUG_ON(irq == -1);
 127 #ifdef CONFIG_SMP
 128         irq_to_desc(irq)->affinity = cpumask_of_cpu(cpu);
 129 #endif
 130
 131         __clear_bit(chn, cpu_evtchn_mask[cpu_evtchn[chn]]);
 132         __set_bit(chn, cpu_evtchn_mask[cpu]);
 133
 134         cpu_evtchn[chn] = cpu;
 135 }
 136
 137 static void init_evtchn_cpu_bindings(void)
 138 {
 139 #ifdef CONFIG_SMP
 140         struct irq_desc *desc;
 141         int i;
 142
 143         /* By default all event channels notify CPU#0. */
 144         for_each_irq_desc(i, desc) {
 145                 if (!desc)
 146                         continue;
 147
 148                 desc->affinity = cpumask_of_cpu(0);
 149         }
 150 #endif
 151
 152         memset(cpu_evtchn, 0, sizeof(cpu_evtchn));
 153         memset(cpu_evtchn_mask[0], ~0, sizeof(cpu_evtchn_mask[0]));
 154 }
 155
 156 static inline unsigned int cpu_from_evtchn(unsigned int evtchn)
 157 {
 158         return cpu_evtchn[evtchn];
 159 }
 160
 161 static inline void clear_evtchn(int port)
 162 {
 163         struct shared_info *s = HYPERVISOR_shared_info;
 164         sync_clear_bit(port, &s->evtchn_pending[0]);
 165 }
 166
 167 static inline void set_evtchn(int port)
 168 {
 169         struct shared_info *s = HYPERVISOR_shared_info;
 170         sync_set_bit(port, &s->evtchn_pending[0]);
 171 }
 172
 173 static inline int test_evtchn(int port)
 174 {
 175         struct shared_info *s = HYPERVISOR_shared_info;
 176         return sync_test_bit(port, &s->evtchn_pending[0]);
 177 }
 178
 179
 180 /**
 181  * notify_remote_via_irq - send event to remote end of event channel via irq
 182  * @irq: irq of event channel to send event to
 183  *
 184  * Unlike notify_remote_via_evtchn(), this is safe to use across
 185  * save/restore. Notifications on a broken connection are silently
 186  * dropped.
 187  */
 188 void notify_remote_via_irq(int irq)
 189 {
 190         int evtchn = evtchn_from_irq(irq);
 191
 192         if (VALID_EVTCHN(evtchn))
 193                 notify_remote_via_evtchn(evtchn);
 194 }
 195 EXPORT_SYMBOL_GPL(notify_remote_via_irq);
 196
 197 static void mask_evtchn(int port)
 198 {
 199         struct shared_info *s = HYPERVISOR_shared_info;
 200         sync_set_bit(port, &s->evtchn_mask[0]);
 201 }
 202
 203 static void unmask_evtchn(int port)
 204 {
 205         struct shared_info *s = HYPERVISOR_shared_info;
 206         unsigned int cpu = get_cpu();
 207
 208         BUG_ON(!irqs_disabled());
 209
 210         /* Slow path (hypercall) if this is a non-local port. */
 211         if (unlikely(cpu != cpu_from_evtchn(port))) {
 212                 struct evtchn_unmask unmask = { .port = port };
 213                 (void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask);
 214         } else {
 215                 struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
 216
 217                 sync_clear_bit(port, &s->evtchn_mask[0]);
 218
 219                 /*
 220                  * The following is basically the equivalent of
 221                  * 'hw_resend_irq'. Just like a real IO-APIC we 'lose
 222                  * the interrupt edge' if the channel is masked.
 223                  */
 224                 if (sync_test_bit(port, &s->evtchn_pending[0]) &&
 225                     !sync_test_and_set_bit(port / BITS_PER_LONG,
 226                                            &vcpu_info->evtchn_pending_sel))
 227                         vcpu_info->evtchn_upcall_pending = 1;
 228         }
 229
 230         put_cpu();
 231 }
 232
 233 static int find_unbound_irq(void)
 234 {
 235         int irq;
 236
 237         /* Only allocate from dynirq range */
 238         for (irq = 0; irq < nr_irqs; irq++)
 239                 if (irq_bindcount[irq] == 0)
 240                         break;
 241
 242         if (irq == nr_irqs)
 243                 panic("No available IRQ to bind to: increase nr_irqs!\n");
 244
 245         return irq;
 246 }
 247
 248 int bind_evtchn_to_irq(unsigned int evtchn)
 249 {
 250         int irq;
 251
 252         spin_lock(&irq_mapping_update_lock);
 253
 254         irq = evtchn_to_irq[evtchn];
 255
 256         if (irq == -1) {
 257                 irq = find_unbound_irq();
 258
 259                 dynamic_irq_init(irq);
 260                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 261                                               handle_level_irq, "event");
 262
 263                 evtchn_to_irq[evtchn] = irq;
 264                 irq_info[irq] = mk_irq_info(IRQT_EVTCHN, 0, evtchn);
 265         }
 266
 267         irq_bindcount[irq]++;
 268
 269         spin_unlock(&irq_mapping_update_lock);
 270
 271         return irq;
 272 }
 273 EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);
 274
 275 static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
 276 {
 277         struct evtchn_bind_ipi bind_ipi;
 278         int evtchn, irq;
 279
 280         spin_lock(&irq_mapping_update_lock);
 281
 282         irq = per_cpu(ipi_to_irq, cpu)[ipi];
 283         if (irq == -1) {
 284                 irq = find_unbound_irq();
 285                 if (irq < 0)
 286                         goto out;
 287
 288                 dynamic_irq_init(irq);
 289                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 290                                               handle_level_irq, "ipi");
 291
 292                 bind_ipi.vcpu = cpu;
 293                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
 294                                                 &bind_ipi) != 0)
 295                         BUG();
 296                 evtchn = bind_ipi.port;
 297
 298                 evtchn_to_irq[evtchn] = irq;
 299                 irq_info[irq] = mk_irq_info(IRQT_IPI, ipi, evtchn);
 300
 301                 per_cpu(ipi_to_irq, cpu)[ipi] = irq;
 302
 303                 bind_evtchn_to_cpu(evtchn, cpu);
 304         }
 305
 306         irq_bindcount[irq]++;
 307
 308  out:
 309         spin_unlock(&irq_mapping_update_lock);
 310         return irq;
 311 }
 312
 313
 314 static int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 315 {
 316         struct evtchn_bind_virq bind_virq;
 317         int evtchn, irq;
 318
 319         spin_lock(&irq_mapping_update_lock);
 320
 321         irq = per_cpu(virq_to_irq, cpu)[virq];
 322
 323         if (irq == -1) {
 324                 bind_virq.virq = virq;
 325                 bind_virq.vcpu = cpu;
 326                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
 327                                                 &bind_virq) != 0)
 328                         BUG();
 329                 evtchn = bind_virq.port;
 330
 331                 irq = find_unbound_irq();
 332
 333                 dynamic_irq_init(irq);
 334                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 335                                               handle_level_irq, "virq");
 336
 337                 evtchn_to_irq[evtchn] = irq;
 338                 irq_info[irq] = mk_irq_info(IRQT_VIRQ, virq, evtchn);
 339
 340                 per_cpu(virq_to_irq, cpu)[virq] = irq;
 341
 342                 bind_evtchn_to_cpu(evtchn, cpu);
 343         }
 344
 345         irq_bindcount[irq]++;
 346
 347         spin_unlock(&irq_mapping_update_lock);
 348
 349         return irq;
 350 }
 351
 352 static void unbind_from_irq(unsigned int irq)
 353 {
 354         struct evtchn_close close;
 355         int evtchn = evtchn_from_irq(irq);
 356
 357         spin_lock(&irq_mapping_update_lock);
 358
 359         if ((--irq_bindcount[irq] == 0) && VALID_EVTCHN(evtchn)) {
 360                 close.port = evtchn;
 361                 if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
 362                         BUG();
 363
 364                 switch (type_from_irq(irq)) {
 365                 case IRQT_VIRQ:
 366                         per_cpu(virq_to_irq, cpu_from_evtchn(evtchn))
 367                                 [index_from_irq(irq)] = -1;
 368                         break;
 369                 case IRQT_IPI:
 370                         per_cpu(ipi_to_irq, cpu_from_evtchn(evtchn))
 371                                 [index_from_irq(irq)] = -1;
 372                         break;
 373                 default:
 374                         break;
 375                 }
 376
 377                 /* Closed ports are implicitly re-bound to VCPU0. */
 378                 bind_evtchn_to_cpu(evtchn, 0);
 379
 380                 evtchn_to_irq[evtchn] = -1;
 381                 irq_info[irq] = IRQ_UNBOUND;
 382
 383                 dynamic_irq_cleanup(irq);
 384         }
 385
 386         spin_unlock(&irq_mapping_update_lock);
 387 }
 388
 389 int bind_evtchn_to_irqhandler(unsigned int evtchn,
 390                               irq_handler_t handler,
 391                               unsigned long irqflags,
 392                               const char *devname, void *dev_id)
 393 {
 394         unsigned int irq;
 395         int retval;
 396
 397         irq = bind_evtchn_to_irq(evtchn);
 398         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 399         if (retval != 0) {
 400                 unbind_from_irq(irq);
 401                 return retval;
 402         }
 403
 404         return irq;
 405 }
 406 EXPORT_SYMBOL_GPL(bind_evtchn_to_irqhandler);
 407
 408 int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
 409                             irq_handler_t handler,
 410                             unsigned long irqflags, const char *devname, void *dev_id)
 411 {
 412         unsigned int irq;
 413         int retval;
 414
 415         irq = bind_virq_to_irq(virq, cpu);
 416         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 417         if (retval != 0) {
 418                 unbind_from_irq(irq);
 419                 return retval;
 420         }
 421
 422         return irq;
 423 }
 424 EXPORT_SYMBOL_GPL(bind_virq_to_irqhandler);
 425
 426 int bind_ipi_to_irqhandler(enum ipi_vector ipi,
 427                            unsigned int cpu,
 428                            irq_handler_t handler,
 429                            unsigned long irqflags,
 430                            const char *devname,
 431                            void *dev_id)
 432 {
 433         int irq, retval;
 434
 435         irq = bind_ipi_to_irq(ipi, cpu);
 436         if (irq < 0)
 437                 return irq;
 438
 439         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 440         if (retval != 0) {
 441                 unbind_from_irq(irq);
 442                 return retval;
 443         }
 444
 445         return irq;
 446 }
 447
 448 void unbind_from_irqhandler(unsigned int irq, void *dev_id)
 449 {
 450         free_irq(irq, dev_id);
 451         unbind_from_irq(irq);
 452 }
 453 EXPORT_SYMBOL_GPL(unbind_from_irqhandler);
 454
 455 void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
 456 {
 457         int irq = per_cpu(ipi_to_irq, cpu)[vector];
 458         BUG_ON(irq < 0);
 459         notify_remote_via_irq(irq);
 460 }
 461
 462 irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 463 {
 464         struct shared_info *sh = HYPERVISOR_shared_info;
 465         int cpu = smp_processor_id();
 466         int i;
 467         unsigned long flags;
 468         static DEFINE_SPINLOCK(debug_lock);
 469
 470         spin_lock_irqsave(&debug_lock, flags);
 471
 472         printk("vcpu %d\n  ", cpu);
 473
 474         for_each_online_cpu(i) {
 475                 struct vcpu_info *v = per_cpu(xen_vcpu, i);
 476                 printk("%d: masked=%d pending=%d event_sel %08lx\n  ", i,
 477                         (get_irq_regs() && i == cpu) ? xen_irqs_disabled(get_irq_regs()) : v->evtchn_upcall_mask,
 478                         v->evtchn_upcall_pending,
 479                         v->evtchn_pending_sel);
 480         }
 481         printk("pending:\n   ");
 482         for(i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--)
 483                 printk("%08lx%s", sh->evtchn_pending[i],
 484                         i % 8 == 0 ? "\n   " : " ");
 485         printk("\nmasks:\n   ");
 486         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
 487                 printk("%08lx%s", sh->evtchn_mask[i],
 488                         i % 8 == 0 ? "\n   " : " ");
 489
 490         printk("\nunmasked:\n   ");
 491         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
 492                 printk("%08lx%s", sh->evtchn_pending[i] & ~sh->evtchn_mask[i],
 493                         i % 8 == 0 ? "\n   " : " ");
 494
 495         printk("\npending list:\n");
 496         for(i = 0; i < NR_EVENT_CHANNELS; i++) {
 497                 if (sync_test_bit(i, sh->evtchn_pending)) {
 498                         printk("  %d: event %d -> irq %d\n",
 499                                 cpu_evtchn[i], i,
 500                                 evtchn_to_irq[i]);
 501                 }
 502         }
 503
 504         spin_unlock_irqrestore(&debug_lock, flags);
 505
 506         return IRQ_HANDLED;
 507 }
 508
 509
 510 /*
 511  * Search the CPUs pending events bitmasks.  For each one found, map
 512  * the event number to an irq, and feed it into do_IRQ() for
 513  * handling.
 514  *
 515  * Xen uses a two-level bitmap to speed searching.  The first level is
 516  * a bitset of words which contain pending event bits.  The second
 517  * level is a bitset of pending events themselves.
 518  */
 519 void xen_evtchn_do_upcall(struct pt_regs *regs)
 520 {
 521         int cpu = get_cpu();
 522         struct shared_info *s = HYPERVISOR_shared_info;
 523         struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
 524         static DEFINE_PER_CPU(unsigned, nesting_count);
 525         unsigned count;
 526
 527         do {
 528                 unsigned long pending_words;
 529
 530                 vcpu_info->evtchn_upcall_pending = 0;
 531
 532                 if (__get_cpu_var(nesting_count)++)
 533                         goto out;
 534
 535 #ifndef CONFIG_X86 /* No need for a barrier -- XCHG is a barrier on x86. */
 536                 /* Clear master flag /before/ clearing selector flag. */
 537                 wmb();
 538 #endif
 539                 pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
 540                 while (pending_words != 0) {
 541                         unsigned long pending_bits;
 542                         int word_idx = __ffs(pending_words);
 543                         pending_words &= ~(1UL << word_idx);
 544
 545                         while ((pending_bits = active_evtchns(cpu, s, word_idx)) != 0) {
 546                                 int bit_idx = __ffs(pending_bits);
 547                                 int port = (word_idx * BITS_PER_LONG) + bit_idx;
 548                                 int irq = evtchn_to_irq[port];
 549
 550                                 if (irq != -1)
 551                                         xen_do_IRQ(irq, regs);
 552                         }
 553                 }
 554
 555                 BUG_ON(!irqs_disabled());
 556
 557                 count = __get_cpu_var(nesting_count);
 558                 __get_cpu_var(nesting_count) = 0;
 559         } while(count != 1);
 560
 561 out:
 562         put_cpu();
 563 }
 564
 565 /* Rebind a new event channel to an existing irq. */
 566 void rebind_evtchn_irq(int evtchn, int irq)
 567 {
 568         /* Make sure the irq is masked, since the new event channel
 569            will also be masked. */
 570         disable_irq(irq);
 571
 572         spin_lock(&irq_mapping_update_lock);
 573
 574         /* After resume the irq<->evtchn mappings are all cleared out */
 575         BUG_ON(evtchn_to_irq[evtchn] != -1);
 576         /* Expect irq to have been bound before,
 577            so the bindcount should be non-0 */
 578         BUG_ON(irq_bindcount[irq] == 0);
 579
 580         evtchn_to_irq[evtchn] = irq;
 581         irq_info[irq] = mk_irq_info(IRQT_EVTCHN, 0, evtchn);
 582
 583         spin_unlock(&irq_mapping_update_lock);
 584
 585         /* new event channels are always bound to cpu 0 */
 586         irq_set_affinity(irq, cpumask_of(0));
 587
 588         /* Unmask the event channel. */
 589         enable_irq(irq);
 590 }
 591
 592 /* Rebind an evtchn so that it gets delivered to a specific cpu */
 593 static void rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
 594 {
 595         struct evtchn_bind_vcpu bind_vcpu;
 596         int evtchn = evtchn_from_irq(irq);
 597
 598         if (!VALID_EVTCHN(evtchn))
 599                 return;
 600
 601         /* Send future instances of this interrupt to other vcpu. */
 602         bind_vcpu.port = evtchn;
 603         bind_vcpu.vcpu = tcpu;
 604
 605         /*
 606          * If this fails, it usually just indicates that we're dealing with a
 607          * virq or IPI channel, which don't actually need to be rebound. Ignore
 608          * it, but don't do the xenlinux-level rebind in that case.
 609          */
 610         if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
 611                 bind_evtchn_to_cpu(evtchn, tcpu);
 612 }
 613
 614
 615 static void set_affinity_irq(unsigned irq, const struct cpumask *dest)
 616 {
 617         unsigned tcpu = cpumask_first(dest);
 618         rebind_irq_to_cpu(irq, tcpu);
 619 }
 620
 621 int resend_irq_on_evtchn(unsigned int irq)
 622 {
 623         int masked, evtchn = evtchn_from_irq(irq);
 624         struct shared_info *s = HYPERVISOR_shared_info;
 625
 626         if (!VALID_EVTCHN(evtchn))
 627                 return 1;
 628
 629         masked = sync_test_and_set_bit(evtchn, s->evtchn_mask);
 630         sync_set_bit(evtchn, s->evtchn_pending);
 631         if (!masked)
 632                 unmask_evtchn(evtchn);
 633
 634         return 1;
 635 }
 636
 637 static void enable_dynirq(unsigned int irq)
 638 {
 639         int evtchn = evtchn_from_irq(irq);
 640
 641         if (VALID_EVTCHN(evtchn))
 642                 unmask_evtchn(evtchn);
 643 }
 644
 645 static void disable_dynirq(unsigned int irq)
 646 {
 647         int evtchn = evtchn_from_irq(irq);
 648
 649         if (VALID_EVTCHN(evtchn))
 650                 mask_evtchn(evtchn);
 651 }
 652
 653 static void ack_dynirq(unsigned int irq)
 654 {
 655         int evtchn = evtchn_from_irq(irq);
 656
 657         move_native_irq(irq);
 658
 659         if (VALID_EVTCHN(evtchn))
 660                 clear_evtchn(evtchn);
 661 }
 662
 663 static int retrigger_dynirq(unsigned int irq)
 664 {
 665         int evtchn = evtchn_from_irq(irq);
 666         struct shared_info *sh = HYPERVISOR_shared_info;
 667         int ret = 0;
 668
 669         if (VALID_EVTCHN(evtchn)) {
 670                 int masked;
 671
 672                 masked = sync_test_and_set_bit(evtchn, sh->evtchn_mask);
 673                 sync_set_bit(evtchn, sh->evtchn_pending);
 674                 if (!masked)
 675                         unmask_evtchn(evtchn);
 676                 ret = 1;
 677         }
 678
 679         return ret;
 680 }
 681
 682 static void restore_cpu_virqs(unsigned int cpu)
 683 {
 684         struct evtchn_bind_virq bind_virq;
 685         int virq, irq, evtchn;
 686
 687         for (virq = 0; virq < NR_VIRQS; virq++) {
 688                 if ((irq = per_cpu(virq_to_irq, cpu)[virq]) == -1)
 689                         continue;
 690
 691                 BUG_ON(irq_info[irq].type != IRQT_VIRQ);
 692                 BUG_ON(irq_info[irq].index != virq);
 693
 694                 /* Get a new binding from Xen. */
 695                 bind_virq.virq = virq;
 696                 bind_virq.vcpu = cpu;
 697                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
 698                                                 &bind_virq) != 0)
 699                         BUG();
 700                 evtchn = bind_virq.port;
 701
 702                 /* Record the new mapping. */
 703                 evtchn_to_irq[evtchn] = irq;
 704                 irq_info[irq] = mk_irq_info(IRQT_VIRQ, virq, evtchn);
 705                 bind_evtchn_to_cpu(evtchn, cpu);
 706
 707                 /* Ready for use. */
 708                 unmask_evtchn(evtchn);
 709         }
 710 }
 711
 712 static void restore_cpu_ipis(unsigned int cpu)
 713 {
 714         struct evtchn_bind_ipi bind_ipi;
 715         int ipi, irq, evtchn;
 716
 717         for (ipi = 0; ipi < XEN_NR_IPIS; ipi++) {
 718                 if ((irq = per_cpu(ipi_to_irq, cpu)[ipi]) == -1)
 719                         continue;
 720
 721                 BUG_ON(irq_info[irq].type != IRQT_IPI);
 722                 BUG_ON(irq_info[irq].index != ipi);
 723
 724                 /* Get a new binding from Xen. */
 725                 bind_ipi.vcpu = cpu;
 726                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
 727                                                 &bind_ipi) != 0)
 728                         BUG();
 729                 evtchn = bind_ipi.port;
 730
 731                 /* Record the new mapping. */
 732                 evtchn_to_irq[evtchn] = irq;
 733                 irq_info[irq] = mk_irq_info(IRQT_IPI, ipi, evtchn);
 734                 bind_evtchn_to_cpu(evtchn, cpu);
 735
 736                 /* Ready for use. */
 737                 unmask_evtchn(evtchn);
 738
 739         }
 740 }
 741
 742 /* Clear an irq's pending state, in preparation for polling on it */
 743 void xen_clear_irq_pending(int irq)
 744 {
 745         int evtchn = evtchn_from_irq(irq);
 746
 747         if (VALID_EVTCHN(evtchn))
 748                 clear_evtchn(evtchn);
 749 }
 750
 751 void xen_set_irq_pending(int irq)
 752 {
 753         int evtchn = evtchn_from_irq(irq);
 754
 755         if (VALID_EVTCHN(evtchn))
 756                 set_evtchn(evtchn);
 757 }
 758
 759 bool xen_test_irq_pending(int irq)
 760 {
 761         int evtchn = evtchn_from_irq(irq);
 762         bool ret = false;
 763
 764         if (VALID_EVTCHN(evtchn))
 765                 ret = test_evtchn(evtchn);
 766
 767         return ret;
 768 }
 769
 770 /* Poll waiting for an irq to become pending.  In the usual case, the
 771    irq will be disabled so it won't deliver an interrupt. */
 772 void xen_poll_irq(int irq)
 773 {
 774         evtchn_port_t evtchn = evtchn_from_irq(irq);
 775
 776         if (VALID_EVTCHN(evtchn)) {
 777                 struct sched_poll poll;
 778
 779                 poll.nr_ports = 1;
 780                 poll.timeout = 0;
 781                 set_xen_guest_handle(poll.ports, &evtchn);
 782
 783                 if (HYPERVISOR_sched_op(SCHEDOP_poll, &poll) != 0)
 784                         BUG();
 785         }
 786 }
 787
 788 void xen_irq_resume(void)
 789 {
 790         unsigned int cpu, irq, evtchn;
 791
 792         init_evtchn_cpu_bindings();
 793
 794         /* New event-channel space is not 'live' yet. */
 795         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
 796                 mask_evtchn(evtchn);
 797
 798         /* No IRQ <-> event-channel mappings. */
 799         for (irq = 0; irq < nr_irqs; irq++)
 800                 irq_info[irq].evtchn = 0; /* zap event-channel binding */
 801
 802         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
 803                 evtchn_to_irq[evtchn] = -1;
 804
 805         for_each_possible_cpu(cpu) {
 806                 restore_cpu_virqs(cpu);
 807                 restore_cpu_ipis(cpu);
 808         }
 809 }
 810
 811 static struct irq_chip xen_dynamic_chip __read_mostly = {
 812         .name           = "xen-dyn",
 813         .mask           = disable_dynirq,
 814         .unmask         = enable_dynirq,
 815         .ack            = ack_dynirq,
 816         .set_affinity   = set_affinity_irq,
 817         .retrigger      = retrigger_dynirq,
 818 };
 819
 820 void __init xen_init_IRQ(void)
 821 {
 822         int i;
 823
 824         init_evtchn_cpu_bindings();
 825
 826         /* No event channels are 'live' right now. */
 827         for (i = 0; i < NR_EVENT_CHANNELS; i++)
 828                 mask_evtchn(i);
 829
 830         /* Dynamic IRQ space is currently unbound. Zero the refcnts. */
 831         for (i = 0; i < nr_irqs; i++)
 832                 irq_bindcount[i] = 0;
 833
 834         irq_ctx_init(smp_processor_id());
 835 }