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