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 struct cpu_evtchn_s {
  79         unsigned long bits[NR_EVENT_CHANNELS/BITS_PER_LONG];
  80 };
  81 static struct cpu_evtchn_s *cpu_evtchn_mask_p;
  82 static inline unsigned long *cpu_evtchn_mask(int cpu)
  83 {
  84         return cpu_evtchn_mask_p[cpu].bits;
  85 }
  86 static u8 cpu_evtchn[NR_EVENT_CHANNELS];
  87
  88 /* Reference counts for bindings to IRQs. */
  89 static int irq_bindcount[NR_IRQS];
  90
  91 /* Xen will never allocate port zero for any purpose. */
  92 #define VALID_EVTCHN(chn)       ((chn) != 0)
  93
  94 static struct irq_chip xen_dynamic_chip;
  95
  96 /* Constructor for packed IRQ information. */
  97 static inline struct packed_irq mk_irq_info(u32 type, u32 index, u32 evtchn)
  98 {
  99         return (struct packed_irq) { evtchn, index, type };
 100 }
 101
 102 /*
 103  * Accessors for packed IRQ information.
 104  */
 105 static inline unsigned int evtchn_from_irq(int irq)
 106 {
 107         return irq_info[irq].evtchn;
 108 }
 109
 110 static inline unsigned int index_from_irq(int irq)
 111 {
 112         return irq_info[irq].index;
 113 }
 114
 115 static inline unsigned int type_from_irq(int irq)
 116 {
 117         return irq_info[irq].type;
 118 }
 119
 120 static inline unsigned long active_evtchns(unsigned int cpu,
 121                                            struct shared_info *sh,
 122                                            unsigned int idx)
 123 {
 124         return (sh->evtchn_pending[idx] &
 125                 cpu_evtchn_mask(cpu)[idx] &
 126                 ~sh->evtchn_mask[idx]);
 127 }
 128
 129 static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
 130 {
 131         int irq = evtchn_to_irq[chn];
 132
 133         BUG_ON(irq == -1);
 134 #ifdef CONFIG_SMP
 135         cpumask_copy(irq_to_desc(irq)->affinity, cpumask_of(cpu));
 136 #endif
 137
 138         __clear_bit(chn, cpu_evtchn_mask(cpu_evtchn[chn]));
 139         __set_bit(chn, cpu_evtchn_mask(cpu));
 140
 141         cpu_evtchn[chn] = cpu;
 142 }
 143
 144 static void init_evtchn_cpu_bindings(void)
 145 {
 146 #ifdef CONFIG_SMP
 147         struct irq_desc *desc;
 148         int i;
 149
 150         /* By default all event channels notify CPU#0. */
 151         for_each_irq_desc(i, desc) {
 152                 cpumask_copy(desc->affinity, cpumask_of(0));
 153         }
 154 #endif
 155
 156         memset(cpu_evtchn, 0, sizeof(cpu_evtchn));
 157         memset(cpu_evtchn_mask(0), ~0, sizeof(cpu_evtchn_mask(0)));
 158 }
 159
 160 static inline unsigned int cpu_from_evtchn(unsigned int evtchn)
 161 {
 162         return cpu_evtchn[evtchn];
 163 }
 164
 165 static inline void clear_evtchn(int port)
 166 {
 167         struct shared_info *s = HYPERVISOR_shared_info;
 168         sync_clear_bit(port, &s->evtchn_pending[0]);
 169 }
 170
 171 static inline void set_evtchn(int port)
 172 {
 173         struct shared_info *s = HYPERVISOR_shared_info;
 174         sync_set_bit(port, &s->evtchn_pending[0]);
 175 }
 176
 177 static inline int test_evtchn(int port)
 178 {
 179         struct shared_info *s = HYPERVISOR_shared_info;
 180         return sync_test_bit(port, &s->evtchn_pending[0]);
 181 }
 182
 183
 184 /**
 185  * notify_remote_via_irq - send event to remote end of event channel via irq
 186  * @irq: irq of event channel to send event to
 187  *
 188  * Unlike notify_remote_via_evtchn(), this is safe to use across
 189  * save/restore. Notifications on a broken connection are silently
 190  * dropped.
 191  */
 192 void notify_remote_via_irq(int irq)
 193 {
 194         int evtchn = evtchn_from_irq(irq);
 195
 196         if (VALID_EVTCHN(evtchn))
 197                 notify_remote_via_evtchn(evtchn);
 198 }
 199 EXPORT_SYMBOL_GPL(notify_remote_via_irq);
 200
 201 static void mask_evtchn(int port)
 202 {
 203         struct shared_info *s = HYPERVISOR_shared_info;
 204         sync_set_bit(port, &s->evtchn_mask[0]);
 205 }
 206
 207 static void unmask_evtchn(int port)
 208 {
 209         struct shared_info *s = HYPERVISOR_shared_info;
 210         unsigned int cpu = get_cpu();
 211
 212         BUG_ON(!irqs_disabled());
 213
 214         /* Slow path (hypercall) if this is a non-local port. */
 215         if (unlikely(cpu != cpu_from_evtchn(port))) {
 216                 struct evtchn_unmask unmask = { .port = port };
 217                 (void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask);
 218         } else {
 219                 struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
 220
 221                 sync_clear_bit(port, &s->evtchn_mask[0]);
 222
 223                 /*
 224                  * The following is basically the equivalent of
 225                  * 'hw_resend_irq'. Just like a real IO-APIC we 'lose
 226                  * the interrupt edge' if the channel is masked.
 227                  */
 228                 if (sync_test_bit(port, &s->evtchn_pending[0]) &&
 229                     !sync_test_and_set_bit(port / BITS_PER_LONG,
 230                                            &vcpu_info->evtchn_pending_sel))
 231                         vcpu_info->evtchn_upcall_pending = 1;
 232         }
 233
 234         put_cpu();
 235 }
 236
 237 static int find_unbound_irq(void)
 238 {
 239         int irq;
 240         struct irq_desc *desc;
 241
 242         /* Only allocate from dynirq range */
 243         for (irq = 0; irq < nr_irqs; irq++)
 244                 if (irq_bindcount[irq] == 0)
 245                         break;
 246
 247         if (irq == nr_irqs)
 248                 panic("No available IRQ to bind to: increase nr_irqs!\n");
 249
 250         desc = irq_to_desc_alloc_cpu(irq, 0);
 251         if (WARN_ON(desc == NULL))
 252                 return -1;
 253
 254         return irq;
 255 }
 256
 257 int bind_evtchn_to_irq(unsigned int evtchn)
 258 {
 259         int irq;
 260
 261         spin_lock(&irq_mapping_update_lock);
 262
 263         irq = evtchn_to_irq[evtchn];
 264
 265         if (irq == -1) {
 266                 irq = find_unbound_irq();
 267
 268                 dynamic_irq_init(irq);
 269                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 270                                               handle_level_irq, "event");
 271
 272                 evtchn_to_irq[evtchn] = irq;
 273                 irq_info[irq] = mk_irq_info(IRQT_EVTCHN, 0, evtchn);
 274         }
 275
 276         irq_bindcount[irq]++;
 277
 278         spin_unlock(&irq_mapping_update_lock);
 279
 280         return irq;
 281 }
 282 EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);
 283
 284 static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
 285 {
 286         struct evtchn_bind_ipi bind_ipi;
 287         int evtchn, irq;
 288
 289         spin_lock(&irq_mapping_update_lock);
 290
 291         irq = per_cpu(ipi_to_irq, cpu)[ipi];
 292         if (irq == -1) {
 293                 irq = find_unbound_irq();
 294                 if (irq < 0)
 295                         goto out;
 296
 297                 dynamic_irq_init(irq);
 298                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 299                                               handle_level_irq, "ipi");
 300
 301                 bind_ipi.vcpu = cpu;
 302                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
 303                                                 &bind_ipi) != 0)
 304                         BUG();
 305                 evtchn = bind_ipi.port;
 306
 307                 evtchn_to_irq[evtchn] = irq;
 308                 irq_info[irq] = mk_irq_info(IRQT_IPI, ipi, evtchn);
 309
 310                 per_cpu(ipi_to_irq, cpu)[ipi] = irq;
 311
 312                 bind_evtchn_to_cpu(evtchn, cpu);
 313         }
 314
 315         irq_bindcount[irq]++;
 316
 317  out:
 318         spin_unlock(&irq_mapping_update_lock);
 319         return irq;
 320 }
 321
 322
 323 static int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 324 {
 325         struct evtchn_bind_virq bind_virq;
 326         int evtchn, irq;
 327
 328         spin_lock(&irq_mapping_update_lock);
 329
 330         irq = per_cpu(virq_to_irq, cpu)[virq];
 331
 332         if (irq == -1) {
 333                 bind_virq.virq = virq;
 334                 bind_virq.vcpu = cpu;
 335                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
 336                                                 &bind_virq) != 0)
 337                         BUG();
 338                 evtchn = bind_virq.port;
 339
 340                 irq = find_unbound_irq();
 341
 342                 dynamic_irq_init(irq);
 343                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 344                                               handle_level_irq, "virq");
 345
 346                 evtchn_to_irq[evtchn] = irq;
 347                 irq_info[irq] = mk_irq_info(IRQT_VIRQ, virq, evtchn);
 348
 349                 per_cpu(virq_to_irq, cpu)[virq] = irq;
 350
 351                 bind_evtchn_to_cpu(evtchn, cpu);
 352         }
 353
 354         irq_bindcount[irq]++;
 355
 356         spin_unlock(&irq_mapping_update_lock);
 357
 358         return irq;
 359 }
 360
 361 static void unbind_from_irq(unsigned int irq)
 362 {
 363         struct evtchn_close close;
 364         int evtchn = evtchn_from_irq(irq);
 365
 366         spin_lock(&irq_mapping_update_lock);
 367
 368         if ((--irq_bindcount[irq] == 0) && VALID_EVTCHN(evtchn)) {
 369                 close.port = evtchn;
 370                 if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
 371                         BUG();
 372
 373                 switch (type_from_irq(irq)) {
 374                 case IRQT_VIRQ:
 375                         per_cpu(virq_to_irq, cpu_from_evtchn(evtchn))
 376                                 [index_from_irq(irq)] = -1;
 377                         break;
 378                 case IRQT_IPI:
 379                         per_cpu(ipi_to_irq, cpu_from_evtchn(evtchn))
 380                                 [index_from_irq(irq)] = -1;
 381                         break;
 382                 default:
 383                         break;
 384                 }
 385
 386                 /* Closed ports are implicitly re-bound to VCPU0. */
 387                 bind_evtchn_to_cpu(evtchn, 0);
 388
 389                 evtchn_to_irq[evtchn] = -1;
 390                 irq_info[irq] = IRQ_UNBOUND;
 391
 392                 dynamic_irq_cleanup(irq);
 393         }
 394
 395         spin_unlock(&irq_mapping_update_lock);
 396 }
 397
 398 int bind_evtchn_to_irqhandler(unsigned int evtchn,
 399                               irq_handler_t handler,
 400                               unsigned long irqflags,
 401                               const char *devname, void *dev_id)
 402 {
 403         unsigned int irq;
 404         int retval;
 405
 406         irq = bind_evtchn_to_irq(evtchn);
 407         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 408         if (retval != 0) {
 409                 unbind_from_irq(irq);
 410                 return retval;
 411         }
 412
 413         return irq;
 414 }
 415 EXPORT_SYMBOL_GPL(bind_evtchn_to_irqhandler);
 416
 417 int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
 418                             irq_handler_t handler,
 419                             unsigned long irqflags, const char *devname, void *dev_id)
 420 {
 421         unsigned int irq;
 422         int retval;
 423
 424         irq = bind_virq_to_irq(virq, cpu);
 425         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 426         if (retval != 0) {
 427                 unbind_from_irq(irq);
 428                 return retval;
 429         }
 430
 431         return irq;
 432 }
 433 EXPORT_SYMBOL_GPL(bind_virq_to_irqhandler);
 434
 435 int bind_ipi_to_irqhandler(enum ipi_vector ipi,
 436                            unsigned int cpu,
 437                            irq_handler_t handler,
 438                            unsigned long irqflags,
 439                            const char *devname,
 440                            void *dev_id)
 441 {
 442         int irq, retval;
 443
 444         irq = bind_ipi_to_irq(ipi, cpu);
 445         if (irq < 0)
 446                 return irq;
 447
 448         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 449         if (retval != 0) {
 450                 unbind_from_irq(irq);
 451                 return retval;
 452         }
 453
 454         return irq;
 455 }
 456
 457 void unbind_from_irqhandler(unsigned int irq, void *dev_id)
 458 {
 459         free_irq(irq, dev_id);
 460         unbind_from_irq(irq);
 461 }
 462 EXPORT_SYMBOL_GPL(unbind_from_irqhandler);
 463
 464 void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
 465 {
 466         int irq = per_cpu(ipi_to_irq, cpu)[vector];
 467         BUG_ON(irq < 0);
 468         notify_remote_via_irq(irq);
 469 }
 470
 471 irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 472 {
 473         struct shared_info *sh = HYPERVISOR_shared_info;
 474         int cpu = smp_processor_id();
 475         int i;
 476         unsigned long flags;
 477         static DEFINE_SPINLOCK(debug_lock);
 478
 479         spin_lock_irqsave(&debug_lock, flags);
 480
 481         printk("vcpu %d\n  ", cpu);
 482
 483         for_each_online_cpu(i) {
 484                 struct vcpu_info *v = per_cpu(xen_vcpu, i);
 485                 printk("%d: masked=%d pending=%d event_sel %08lx\n  ", i,
 486                         (get_irq_regs() && i == cpu) ? xen_irqs_disabled(get_irq_regs()) : v->evtchn_upcall_mask,
 487                         v->evtchn_upcall_pending,
 488                         v->evtchn_pending_sel);
 489         }
 490         printk("pending:\n   ");
 491         for(i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--)
 492                 printk("%08lx%s", sh->evtchn_pending[i],
 493                         i % 8 == 0 ? "\n   " : " ");
 494         printk("\nmasks:\n   ");
 495         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
 496                 printk("%08lx%s", sh->evtchn_mask[i],
 497                         i % 8 == 0 ? "\n   " : " ");
 498
 499         printk("\nunmasked:\n   ");
 500         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
 501                 printk("%08lx%s", sh->evtchn_pending[i] & ~sh->evtchn_mask[i],
 502                         i % 8 == 0 ? "\n   " : " ");
 503
 504         printk("\npending list:\n");
 505         for(i = 0; i < NR_EVENT_CHANNELS; i++) {
 506                 if (sync_test_bit(i, sh->evtchn_pending)) {
 507                         printk("  %d: event %d -> irq %d\n",
 508                                 cpu_evtchn[i], i,
 509                                 evtchn_to_irq[i]);
 510                 }
 511         }
 512
 513         spin_unlock_irqrestore(&debug_lock, flags);
 514
 515         return IRQ_HANDLED;
 516 }
 517
 518
 519 /*
 520  * Search the CPUs pending events bitmasks.  For each one found, map
 521  * the event number to an irq, and feed it into do_IRQ() for
 522  * handling.
 523  *
 524  * Xen uses a two-level bitmap to speed searching.  The first level is
 525  * a bitset of words which contain pending event bits.  The second
 526  * level is a bitset of pending events themselves.
 527  */
 528 void xen_evtchn_do_upcall(struct pt_regs *regs)
 529 {
 530         int cpu = get_cpu();
 531         struct shared_info *s = HYPERVISOR_shared_info;
 532         struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
 533         static DEFINE_PER_CPU(unsigned, nesting_count);
 534         unsigned count;
 535
 536         do {
 537                 unsigned long pending_words;
 538
 539                 vcpu_info->evtchn_upcall_pending = 0;
 540
 541                 if (__get_cpu_var(nesting_count)++)
 542                         goto out;
 543
 544 #ifndef CONFIG_X86 /* No need for a barrier -- XCHG is a barrier on x86. */
 545                 /* Clear master flag /before/ clearing selector flag. */
 546                 wmb();
 547 #endif
 548                 pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
 549                 while (pending_words != 0) {
 550                         unsigned long pending_bits;
 551                         int word_idx = __ffs(pending_words);
 552                         pending_words &= ~(1UL << word_idx);
 553
 554                         while ((pending_bits = active_evtchns(cpu, s, word_idx)) != 0) {
 555                                 int bit_idx = __ffs(pending_bits);
 556                                 int port = (word_idx * BITS_PER_LONG) + bit_idx;
 557                                 int irq = evtchn_to_irq[port];
 558
 559                                 if (irq != -1)
 560                                         xen_do_IRQ(irq, regs);
 561                         }
 562                 }
 563
 564                 BUG_ON(!irqs_disabled());
 565
 566                 count = __get_cpu_var(nesting_count);
 567                 __get_cpu_var(nesting_count) = 0;
 568         } while(count != 1);
 569
 570 out:
 571         put_cpu();
 572 }
 573
 574 /* Rebind a new event channel to an existing irq. */
 575 void rebind_evtchn_irq(int evtchn, int irq)
 576 {
 577         /* Make sure the irq is masked, since the new event channel
 578            will also be masked. */
 579         disable_irq(irq);
 580
 581         spin_lock(&irq_mapping_update_lock);
 582
 583         /* After resume the irq<->evtchn mappings are all cleared out */
 584         BUG_ON(evtchn_to_irq[evtchn] != -1);
 585         /* Expect irq to have been bound before,
 586            so the bindcount should be non-0 */
 587         BUG_ON(irq_bindcount[irq] == 0);
 588
 589         evtchn_to_irq[evtchn] = irq;
 590         irq_info[irq] = mk_irq_info(IRQT_EVTCHN, 0, evtchn);
 591
 592         spin_unlock(&irq_mapping_update_lock);
 593
 594         /* new event channels are always bound to cpu 0 */
 595         irq_set_affinity(irq, cpumask_of(0));
 596
 597         /* Unmask the event channel. */
 598         enable_irq(irq);
 599 }
 600
 601 /* Rebind an evtchn so that it gets delivered to a specific cpu */
 602 static void rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
 603 {
 604         struct evtchn_bind_vcpu bind_vcpu;
 605         int evtchn = evtchn_from_irq(irq);
 606
 607         if (!VALID_EVTCHN(evtchn))
 608                 return;
 609
 610         /* Send future instances of this interrupt to other vcpu. */
 611         bind_vcpu.port = evtchn;
 612         bind_vcpu.vcpu = tcpu;
 613
 614         /*
 615          * If this fails, it usually just indicates that we're dealing with a
 616          * virq or IPI channel, which don't actually need to be rebound. Ignore
 617          * it, but don't do the xenlinux-level rebind in that case.
 618          */
 619         if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
 620                 bind_evtchn_to_cpu(evtchn, tcpu);
 621 }
 622
 623
 624 static void set_affinity_irq(unsigned irq, const struct cpumask *dest)
 625 {
 626         unsigned tcpu = cpumask_first(dest);
 627         rebind_irq_to_cpu(irq, tcpu);
 628 }
 629
 630 int resend_irq_on_evtchn(unsigned int irq)
 631 {
 632         int masked, evtchn = evtchn_from_irq(irq);
 633         struct shared_info *s = HYPERVISOR_shared_info;
 634
 635         if (!VALID_EVTCHN(evtchn))
 636                 return 1;
 637
 638         masked = sync_test_and_set_bit(evtchn, s->evtchn_mask);
 639         sync_set_bit(evtchn, s->evtchn_pending);
 640         if (!masked)
 641                 unmask_evtchn(evtchn);
 642
 643         return 1;
 644 }
 645
 646 static void enable_dynirq(unsigned int irq)
 647 {
 648         int evtchn = evtchn_from_irq(irq);
 649
 650         if (VALID_EVTCHN(evtchn))
 651                 unmask_evtchn(evtchn);
 652 }
 653
 654 static void disable_dynirq(unsigned int irq)
 655 {
 656         int evtchn = evtchn_from_irq(irq);
 657
 658         if (VALID_EVTCHN(evtchn))
 659                 mask_evtchn(evtchn);
 660 }
 661
 662 static void ack_dynirq(unsigned int irq)
 663 {
 664         int evtchn = evtchn_from_irq(irq);
 665
 666         move_native_irq(irq);
 667
 668         if (VALID_EVTCHN(evtchn))
 669                 clear_evtchn(evtchn);
 670 }
 671
 672 static int retrigger_dynirq(unsigned int irq)
 673 {
 674         int evtchn = evtchn_from_irq(irq);
 675         struct shared_info *sh = HYPERVISOR_shared_info;
 676         int ret = 0;
 677
 678         if (VALID_EVTCHN(evtchn)) {
 679                 int masked;
 680
 681                 masked = sync_test_and_set_bit(evtchn, sh->evtchn_mask);
 682                 sync_set_bit(evtchn, sh->evtchn_pending);
 683                 if (!masked)
 684                         unmask_evtchn(evtchn);
 685                 ret = 1;
 686         }
 687
 688         return ret;
 689 }
 690
 691 static void restore_cpu_virqs(unsigned int cpu)
 692 {
 693         struct evtchn_bind_virq bind_virq;
 694         int virq, irq, evtchn;
 695
 696         for (virq = 0; virq < NR_VIRQS; virq++) {
 697                 if ((irq = per_cpu(virq_to_irq, cpu)[virq]) == -1)
 698                         continue;
 699
 700                 BUG_ON(irq_info[irq].type != IRQT_VIRQ);
 701                 BUG_ON(irq_info[irq].index != virq);
 702
 703                 /* Get a new binding from Xen. */
 704                 bind_virq.virq = virq;
 705                 bind_virq.vcpu = cpu;
 706                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
 707                                                 &bind_virq) != 0)
 708                         BUG();
 709                 evtchn = bind_virq.port;
 710
 711                 /* Record the new mapping. */
 712                 evtchn_to_irq[evtchn] = irq;
 713                 irq_info[irq] = mk_irq_info(IRQT_VIRQ, virq, evtchn);
 714                 bind_evtchn_to_cpu(evtchn, cpu);
 715
 716                 /* Ready for use. */
 717                 unmask_evtchn(evtchn);
 718         }
 719 }
 720
 721 static void restore_cpu_ipis(unsigned int cpu)
 722 {
 723         struct evtchn_bind_ipi bind_ipi;
 724         int ipi, irq, evtchn;
 725
 726         for (ipi = 0; ipi < XEN_NR_IPIS; ipi++) {
 727                 if ((irq = per_cpu(ipi_to_irq, cpu)[ipi]) == -1)
 728                         continue;
 729
 730                 BUG_ON(irq_info[irq].type != IRQT_IPI);
 731                 BUG_ON(irq_info[irq].index != ipi);
 732
 733                 /* Get a new binding from Xen. */
 734                 bind_ipi.vcpu = cpu;
 735                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
 736                                                 &bind_ipi) != 0)
 737                         BUG();
 738                 evtchn = bind_ipi.port;
 739
 740                 /* Record the new mapping. */
 741                 evtchn_to_irq[evtchn] = irq;
 742                 irq_info[irq] = mk_irq_info(IRQT_IPI, ipi, evtchn);
 743                 bind_evtchn_to_cpu(evtchn, cpu);
 744
 745                 /* Ready for use. */
 746                 unmask_evtchn(evtchn);
 747
 748         }
 749 }
 750
 751 /* Clear an irq's pending state, in preparation for polling on it */
 752 void xen_clear_irq_pending(int irq)
 753 {
 754         int evtchn = evtchn_from_irq(irq);
 755
 756         if (VALID_EVTCHN(evtchn))
 757                 clear_evtchn(evtchn);
 758 }
 759
 760 void xen_set_irq_pending(int irq)
 761 {
 762         int evtchn = evtchn_from_irq(irq);
 763
 764         if (VALID_EVTCHN(evtchn))
 765                 set_evtchn(evtchn);
 766 }
 767
 768 bool xen_test_irq_pending(int irq)
 769 {
 770         int evtchn = evtchn_from_irq(irq);
 771         bool ret = false;
 772
 773         if (VALID_EVTCHN(evtchn))
 774                 ret = test_evtchn(evtchn);
 775
 776         return ret;
 777 }
 778
 779 /* Poll waiting for an irq to become pending.  In the usual case, the
 780    irq will be disabled so it won't deliver an interrupt. */
 781 void xen_poll_irq(int irq)
 782 {
 783         evtchn_port_t evtchn = evtchn_from_irq(irq);
 784
 785         if (VALID_EVTCHN(evtchn)) {
 786                 struct sched_poll poll;
 787
 788                 poll.nr_ports = 1;
 789                 poll.timeout = 0;
 790                 set_xen_guest_handle(poll.ports, &evtchn);
 791
 792                 if (HYPERVISOR_sched_op(SCHEDOP_poll, &poll) != 0)
 793                         BUG();
 794         }
 795 }
 796
 797 void xen_irq_resume(void)
 798 {
 799         unsigned int cpu, irq, evtchn;
 800
 801         init_evtchn_cpu_bindings();
 802
 803         /* New event-channel space is not 'live' yet. */
 804         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
 805                 mask_evtchn(evtchn);
 806
 807         /* No IRQ <-> event-channel mappings. */
 808         for (irq = 0; irq < nr_irqs; irq++)
 809                 irq_info[irq].evtchn = 0; /* zap event-channel binding */
 810
 811         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
 812                 evtchn_to_irq[evtchn] = -1;
 813
 814         for_each_possible_cpu(cpu) {
 815                 restore_cpu_virqs(cpu);
 816                 restore_cpu_ipis(cpu);
 817         }
 818 }
 819
 820 static struct irq_chip xen_dynamic_chip __read_mostly = {
 821         .name           = "xen-dyn",
 822         .mask           = disable_dynirq,
 823         .unmask         = enable_dynirq,
 824         .ack            = ack_dynirq,
 825         .set_affinity   = set_affinity_irq,
 826         .retrigger      = retrigger_dynirq,
 827 };
 828
 829 void __init xen_init_IRQ(void)
 830 {
 831         int i;
 832         size_t size = nr_cpu_ids * sizeof(struct cpu_evtchn_s);
 833
 834         cpu_evtchn_mask_p = kmalloc(size, GFP_KERNEL);
 835         BUG_ON(cpu_evtchn_mask == NULL);
 836
 837         init_evtchn_cpu_bindings();
 838
 839         /* No event channels are 'live' right now. */
 840         for (i = 0; i < NR_EVENT_CHANNELS; i++)
 841                 mask_evtchn(i);
 842
 843         /* Dynamic IRQ space is currently unbound. Zero the refcnts. */
 844         for (i = 0; i < nr_irqs; i++)
 845                 irq_bindcount[i] = 0;
 846
 847         irq_ctx_init(smp_processor_id());
 848 }