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 #include <linux/bootmem.h>
  30
  31 #include <asm/ptrace.h>
  32 #include <asm/irq.h>
  33 #include <asm/idle.h>
  34 #include <asm/sync_bitops.h>
  35 #include <asm/xen/hypercall.h>
  36 #include <asm/xen/hypervisor.h>
  37
  38 #include <xen/xen-ops.h>
  39 #include <xen/events.h>
  40 #include <xen/interface/xen.h>
  41 #include <xen/interface/event_channel.h>
  42
  43 /*
  44  * This lock protects updates to the following mapping and reference-count
  45  * arrays. The lock does not need to be acquired to read the mapping tables.
  46  */
  47 static DEFINE_SPINLOCK(irq_mapping_update_lock);
  48
  49 /* IRQ <-> VIRQ mapping. */
  50 static DEFINE_PER_CPU(int, virq_to_irq[NR_VIRQS]) = {[0 ... NR_VIRQS-1] = -1};
  51
  52 /* IRQ <-> IPI mapping */
  53 static DEFINE_PER_CPU(int, ipi_to_irq[XEN_NR_IPIS]) = {[0 ... XEN_NR_IPIS-1] = -1};
  54
  55 /* Interrupt types. */
  56 enum xen_irq_type {
  57         IRQT_UNBOUND,
  58         IRQT_PIRQ,
  59         IRQT_VIRQ,
  60         IRQT_IPI,
  61         IRQT_EVTCHN
  62 };
  63
  64 /*
  65  * Packed IRQ information:
  66  * type - enum xen_irq_type
  67  * event channel - irq->event channel mapping
  68  * cpu - cpu this event channel is bound to
  69  * index - type-specific information:
  70  *    PIRQ - vector, with MSB being "needs EIO"
  71  *    VIRQ - virq number
  72  *    IPI - IPI vector
  73  *    EVTCHN -
  74  */
  75 struct irq_info
  76 {
  77         enum xen_irq_type type; /* type */
  78         unsigned short evtchn;  /* event channel */
  79         unsigned short cpu;     /* cpu bound */
  80
  81         union {
  82                 unsigned short virq;
  83                 enum ipi_vector ipi;
  84                 struct {
  85                         unsigned short gsi;
  86                         unsigned short vector;
  87                 } pirq;
  88         } u;
  89 };
  90
  91 static struct irq_info irq_info[NR_IRQS];
  92
  93 static int evtchn_to_irq[NR_EVENT_CHANNELS] = {
  94         [0 ... NR_EVENT_CHANNELS-1] = -1
  95 };
  96 struct cpu_evtchn_s {
  97         unsigned long bits[NR_EVENT_CHANNELS/BITS_PER_LONG];
  98 };
  99 static struct cpu_evtchn_s *cpu_evtchn_mask_p;
 100 static inline unsigned long *cpu_evtchn_mask(int cpu)
 101 {
 102         return cpu_evtchn_mask_p[cpu].bits;
 103 }
 104
 105 /* Reference counts for bindings to IRQs. */
 106 static int irq_bindcount[NR_IRQS];
 107
 108 /* Xen will never allocate port zero for any purpose. */
 109 #define VALID_EVTCHN(chn)       ((chn) != 0)
 110
 111 static struct irq_chip xen_dynamic_chip;
 112
 113 /* Constructor for packed IRQ information. */
 114 static struct irq_info mk_unbound_info(void)
 115 {
 116         return (struct irq_info) { .type = IRQT_UNBOUND };
 117 }
 118
 119 static struct irq_info mk_evtchn_info(unsigned short evtchn)
 120 {
 121         return (struct irq_info) { .type = IRQT_EVTCHN, .evtchn = evtchn };
 122 }
 123
 124 static struct irq_info mk_ipi_info(unsigned short evtchn, enum ipi_vector ipi)
 125 {
 126         return (struct irq_info) { .type = IRQT_IPI, .evtchn = evtchn,
 127                         .u.ipi = ipi };
 128 }
 129
 130 static struct irq_info mk_virq_info(unsigned short evtchn, unsigned short virq)
 131 {
 132         return (struct irq_info) { .type = IRQT_VIRQ, .evtchn = evtchn,
 133                         .u.virq = virq };
 134 }
 135
 136 static struct irq_info mk_pirq_info(unsigned short evtchn,
 137                                     unsigned short gsi, unsigned short vector)
 138 {
 139         return (struct irq_info) { .type = IRQT_PIRQ, .evtchn = evtchn,
 140                         .u.pirq = { .gsi = gsi, .vector = vector } };
 141 }
 142
 143 /*
 144  * Accessors for packed IRQ information.
 145  */
 146 static struct irq_info *info_for_irq(unsigned irq)
 147 {
 148         return &irq_info[irq];
 149 }
 150
 151 static unsigned int evtchn_from_irq(unsigned irq)
 152 {
 153         return info_for_irq(irq)->evtchn;
 154 }
 155
 156 static enum ipi_vector ipi_from_irq(unsigned irq)
 157 {
 158         struct irq_info *info = info_for_irq(irq);
 159
 160         BUG_ON(info == NULL);
 161         BUG_ON(info->type != IRQT_IPI);
 162
 163         return info->u.ipi;
 164 }
 165
 166 static unsigned virq_from_irq(unsigned irq)
 167 {
 168         struct irq_info *info = info_for_irq(irq);
 169
 170         BUG_ON(info == NULL);
 171         BUG_ON(info->type != IRQT_VIRQ);
 172
 173         return info->u.virq;
 174 }
 175
 176 static unsigned gsi_from_irq(unsigned irq)
 177 {
 178         struct irq_info *info = info_for_irq(irq);
 179
 180         BUG_ON(info == NULL);
 181         BUG_ON(info->type != IRQT_PIRQ);
 182
 183         return info->u.pirq.gsi;
 184 }
 185
 186 static unsigned vector_from_irq(unsigned irq)
 187 {
 188         struct irq_info *info = info_for_irq(irq);
 189
 190         BUG_ON(info == NULL);
 191         BUG_ON(info->type != IRQT_PIRQ);
 192
 193         return info->u.pirq.vector;
 194 }
 195
 196 static enum xen_irq_type type_from_irq(unsigned irq)
 197 {
 198         return info_for_irq(irq)->type;
 199 }
 200
 201 static unsigned cpu_from_irq(unsigned irq)
 202 {
 203         return info_for_irq(irq)->cpu;
 204 }
 205
 206 static unsigned int cpu_from_evtchn(unsigned int evtchn)
 207 {
 208         int irq = evtchn_to_irq[evtchn];
 209         unsigned ret = 0;
 210
 211         if (irq != -1)
 212                 ret = cpu_from_irq(irq);
 213
 214         return ret;
 215 }
 216
 217 static inline unsigned long active_evtchns(unsigned int cpu,
 218                                            struct shared_info *sh,
 219                                            unsigned int idx)
 220 {
 221         return (sh->evtchn_pending[idx] &
 222                 cpu_evtchn_mask(cpu)[idx] &
 223                 ~sh->evtchn_mask[idx]);
 224 }
 225
 226 static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
 227 {
 228         int irq = evtchn_to_irq[chn];
 229
 230         BUG_ON(irq == -1);
 231 #ifdef CONFIG_SMP
 232         cpumask_copy(irq_to_desc(irq)->affinity, cpumask_of(cpu));
 233 #endif
 234
 235         __clear_bit(chn, cpu_evtchn_mask(cpu_from_irq(irq)));
 236         __set_bit(chn, cpu_evtchn_mask(cpu));
 237
 238         irq_info[irq].cpu = cpu;
 239 }
 240
 241 static void init_evtchn_cpu_bindings(void)
 242 {
 243 #ifdef CONFIG_SMP
 244         struct irq_desc *desc;
 245         int i;
 246
 247         /* By default all event channels notify CPU#0. */
 248         for_each_irq_desc(i, desc) {
 249                 cpumask_copy(desc->affinity, cpumask_of(0));
 250         }
 251 #endif
 252
 253         memset(cpu_evtchn_mask(0), ~0, sizeof(cpu_evtchn_mask(0)));
 254 }
 255
 256 static inline void clear_evtchn(int port)
 257 {
 258         struct shared_info *s = HYPERVISOR_shared_info;
 259         sync_clear_bit(port, &s->evtchn_pending[0]);
 260 }
 261
 262 static inline void set_evtchn(int port)
 263 {
 264         struct shared_info *s = HYPERVISOR_shared_info;
 265         sync_set_bit(port, &s->evtchn_pending[0]);
 266 }
 267
 268 static inline int test_evtchn(int port)
 269 {
 270         struct shared_info *s = HYPERVISOR_shared_info;
 271         return sync_test_bit(port, &s->evtchn_pending[0]);
 272 }
 273
 274
 275 /**
 276  * notify_remote_via_irq - send event to remote end of event channel via irq
 277  * @irq: irq of event channel to send event to
 278  *
 279  * Unlike notify_remote_via_evtchn(), this is safe to use across
 280  * save/restore. Notifications on a broken connection are silently
 281  * dropped.
 282  */
 283 void notify_remote_via_irq(int irq)
 284 {
 285         int evtchn = evtchn_from_irq(irq);
 286
 287         if (VALID_EVTCHN(evtchn))
 288                 notify_remote_via_evtchn(evtchn);
 289 }
 290 EXPORT_SYMBOL_GPL(notify_remote_via_irq);
 291
 292 static void mask_evtchn(int port)
 293 {
 294         struct shared_info *s = HYPERVISOR_shared_info;
 295         sync_set_bit(port, &s->evtchn_mask[0]);
 296 }
 297
 298 static void unmask_evtchn(int port)
 299 {
 300         struct shared_info *s = HYPERVISOR_shared_info;
 301         unsigned int cpu = get_cpu();
 302
 303         BUG_ON(!irqs_disabled());
 304
 305         /* Slow path (hypercall) if this is a non-local port. */
 306         if (unlikely(cpu != cpu_from_evtchn(port))) {
 307                 struct evtchn_unmask unmask = { .port = port };
 308                 (void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask);
 309         } else {
 310                 struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
 311
 312                 sync_clear_bit(port, &s->evtchn_mask[0]);
 313
 314                 /*
 315                  * The following is basically the equivalent of
 316                  * 'hw_resend_irq'. Just like a real IO-APIC we 'lose
 317                  * the interrupt edge' if the channel is masked.
 318                  */
 319                 if (sync_test_bit(port, &s->evtchn_pending[0]) &&
 320                     !sync_test_and_set_bit(port / BITS_PER_LONG,
 321                                            &vcpu_info->evtchn_pending_sel))
 322                         vcpu_info->evtchn_upcall_pending = 1;
 323         }
 324
 325         put_cpu();
 326 }
 327
 328 static int find_unbound_irq(void)
 329 {
 330         int irq;
 331         struct irq_desc *desc;
 332
 333         /* Only allocate from dynirq range */
 334         for (irq = 0; irq < nr_irqs; irq++)
 335                 if (irq_bindcount[irq] == 0)
 336                         break;
 337
 338         if (irq == nr_irqs)
 339                 panic("No available IRQ to bind to: increase nr_irqs!\n");
 340
 341         desc = irq_to_desc_alloc_cpu(irq, 0);
 342         if (WARN_ON(desc == NULL))
 343                 return -1;
 344
 345         dynamic_irq_init(irq);
 346
 347         return irq;
 348 }
 349
 350 int bind_evtchn_to_irq(unsigned int evtchn)
 351 {
 352         int irq;
 353
 354         spin_lock(&irq_mapping_update_lock);
 355
 356         irq = evtchn_to_irq[evtchn];
 357
 358         if (irq == -1) {
 359                 irq = find_unbound_irq();
 360
 361                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 362                                               handle_level_irq, "event");
 363
 364                 evtchn_to_irq[evtchn] = irq;
 365                 irq_info[irq] = mk_evtchn_info(evtchn);
 366         }
 367
 368         irq_bindcount[irq]++;
 369
 370         spin_unlock(&irq_mapping_update_lock);
 371
 372         return irq;
 373 }
 374 EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);
 375
 376 static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
 377 {
 378         struct evtchn_bind_ipi bind_ipi;
 379         int evtchn, irq;
 380
 381         spin_lock(&irq_mapping_update_lock);
 382
 383         irq = per_cpu(ipi_to_irq, cpu)[ipi];
 384         if (irq == -1) {
 385                 irq = find_unbound_irq();
 386                 if (irq < 0)
 387                         goto out;
 388
 389                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 390                                               handle_level_irq, "ipi");
 391
 392                 bind_ipi.vcpu = cpu;
 393                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
 394                                                 &bind_ipi) != 0)
 395                         BUG();
 396                 evtchn = bind_ipi.port;
 397
 398                 evtchn_to_irq[evtchn] = irq;
 399                 irq_info[irq] = mk_ipi_info(evtchn, ipi);
 400
 401                 per_cpu(ipi_to_irq, cpu)[ipi] = irq;
 402
 403                 bind_evtchn_to_cpu(evtchn, cpu);
 404         }
 405
 406         irq_bindcount[irq]++;
 407
 408  out:
 409         spin_unlock(&irq_mapping_update_lock);
 410         return irq;
 411 }
 412
 413
 414 static int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 415 {
 416         struct evtchn_bind_virq bind_virq;
 417         int evtchn, irq;
 418
 419         spin_lock(&irq_mapping_update_lock);
 420
 421         irq = per_cpu(virq_to_irq, cpu)[virq];
 422
 423         if (irq == -1) {
 424                 bind_virq.virq = virq;
 425                 bind_virq.vcpu = cpu;
 426                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
 427                                                 &bind_virq) != 0)
 428                         BUG();
 429                 evtchn = bind_virq.port;
 430
 431                 irq = find_unbound_irq();
 432
 433                 set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
 434                                               handle_level_irq, "virq");
 435
 436                 evtchn_to_irq[evtchn] = irq;
 437                 irq_info[irq] = mk_virq_info(evtchn, virq);
 438
 439                 per_cpu(virq_to_irq, cpu)[virq] = irq;
 440
 441                 bind_evtchn_to_cpu(evtchn, cpu);
 442         }
 443
 444         irq_bindcount[irq]++;
 445
 446         spin_unlock(&irq_mapping_update_lock);
 447
 448         return irq;
 449 }
 450
 451 static void unbind_from_irq(unsigned int irq)
 452 {
 453         struct evtchn_close close;
 454         int evtchn = evtchn_from_irq(irq);
 455
 456         spin_lock(&irq_mapping_update_lock);
 457
 458         if ((--irq_bindcount[irq] == 0) && VALID_EVTCHN(evtchn)) {
 459                 close.port = evtchn;
 460                 if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
 461                         BUG();
 462
 463                 switch (type_from_irq(irq)) {
 464                 case IRQT_VIRQ:
 465                         per_cpu(virq_to_irq, cpu_from_evtchn(evtchn))
 466                                 [virq_from_irq(irq)] = -1;
 467                         break;
 468                 case IRQT_IPI:
 469                         per_cpu(ipi_to_irq, cpu_from_evtchn(evtchn))
 470                                 [ipi_from_irq(irq)] = -1;
 471                         break;
 472                 default:
 473                         break;
 474                 }
 475
 476                 /* Closed ports are implicitly re-bound to VCPU0. */
 477                 bind_evtchn_to_cpu(evtchn, 0);
 478
 479                 evtchn_to_irq[evtchn] = -1;
 480                 irq_info[irq] = mk_unbound_info();
 481
 482                 dynamic_irq_cleanup(irq);
 483         }
 484
 485         spin_unlock(&irq_mapping_update_lock);
 486 }
 487
 488 int bind_evtchn_to_irqhandler(unsigned int evtchn,
 489                               irq_handler_t handler,
 490                               unsigned long irqflags,
 491                               const char *devname, void *dev_id)
 492 {
 493         unsigned int irq;
 494         int retval;
 495
 496         irq = bind_evtchn_to_irq(evtchn);
 497         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 498         if (retval != 0) {
 499                 unbind_from_irq(irq);
 500                 return retval;
 501         }
 502
 503         return irq;
 504 }
 505 EXPORT_SYMBOL_GPL(bind_evtchn_to_irqhandler);
 506
 507 int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
 508                             irq_handler_t handler,
 509                             unsigned long irqflags, const char *devname, void *dev_id)
 510 {
 511         unsigned int irq;
 512         int retval;
 513
 514         irq = bind_virq_to_irq(virq, cpu);
 515         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 516         if (retval != 0) {
 517                 unbind_from_irq(irq);
 518                 return retval;
 519         }
 520
 521         return irq;
 522 }
 523 EXPORT_SYMBOL_GPL(bind_virq_to_irqhandler);
 524
 525 int bind_ipi_to_irqhandler(enum ipi_vector ipi,
 526                            unsigned int cpu,
 527                            irq_handler_t handler,
 528                            unsigned long irqflags,
 529                            const char *devname,
 530                            void *dev_id)
 531 {
 532         int irq, retval;
 533
 534         irq = bind_ipi_to_irq(ipi, cpu);
 535         if (irq < 0)
 536                 return irq;
 537
 538         retval = request_irq(irq, handler, irqflags, devname, dev_id);
 539         if (retval != 0) {
 540                 unbind_from_irq(irq);
 541                 return retval;
 542         }
 543
 544         return irq;
 545 }
 546
 547 void unbind_from_irqhandler(unsigned int irq, void *dev_id)
 548 {
 549         free_irq(irq, dev_id);
 550         unbind_from_irq(irq);
 551 }
 552 EXPORT_SYMBOL_GPL(unbind_from_irqhandler);
 553
 554 void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
 555 {
 556         int irq = per_cpu(ipi_to_irq, cpu)[vector];
 557         BUG_ON(irq < 0);
 558         notify_remote_via_irq(irq);
 559 }
 560
 561 irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 562 {
 563         struct shared_info *sh = HYPERVISOR_shared_info;
 564         int cpu = smp_processor_id();
 565         int i;
 566         unsigned long flags;
 567         static DEFINE_SPINLOCK(debug_lock);
 568
 569         spin_lock_irqsave(&debug_lock, flags);
 570
 571         printk("vcpu %d\n  ", cpu);
 572
 573         for_each_online_cpu(i) {
 574                 struct vcpu_info *v = per_cpu(xen_vcpu, i);
 575                 printk("%d: masked=%d pending=%d event_sel %08lx\n  ", i,
 576                         (get_irq_regs() && i == cpu) ? xen_irqs_disabled(get_irq_regs()) : v->evtchn_upcall_mask,
 577                         v->evtchn_upcall_pending,
 578                         v->evtchn_pending_sel);
 579         }
 580         printk("pending:\n   ");
 581         for(i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--)
 582                 printk("%08lx%s", sh->evtchn_pending[i],
 583                         i % 8 == 0 ? "\n   " : " ");
 584         printk("\nmasks:\n   ");
 585         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
 586                 printk("%08lx%s", sh->evtchn_mask[i],
 587                         i % 8 == 0 ? "\n   " : " ");
 588
 589         printk("\nunmasked:\n   ");
 590         for(i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
 591                 printk("%08lx%s", sh->evtchn_pending[i] & ~sh->evtchn_mask[i],
 592                         i % 8 == 0 ? "\n   " : " ");
 593
 594         printk("\npending list:\n");
 595         for(i = 0; i < NR_EVENT_CHANNELS; i++) {
 596                 if (sync_test_bit(i, sh->evtchn_pending)) {
 597                         printk("  %d: event %d -> irq %d\n",
 598                                cpu_from_evtchn(i), i,
 599                                evtchn_to_irq[i]);
 600                 }
 601         }
 602
 603         spin_unlock_irqrestore(&debug_lock, flags);
 604
 605         return IRQ_HANDLED;
 606 }
 607
 608
 609 static void xen_do_irq(unsigned irq, struct pt_regs *regs)
 610 {
 611         struct pt_regs *old_regs = set_irq_regs(regs);
 612
 613         if (WARN_ON(irq == -1))
 614                 return;
 615
 616         exit_idle();
 617         irq_enter();
 618
 619         //printk("cpu %d handling irq %d\n", smp_processor_id(), info->irq);
 620         handle_irq(irq, regs);
 621
 622         irq_exit();
 623
 624         set_irq_regs(old_regs);
 625 }
 626
 627 /*
 628  * Search the CPUs pending events bitmasks.  For each one found, map
 629  * the event number to an irq, and feed it into do_IRQ() for
 630  * handling.
 631  *
 632  * Xen uses a two-level bitmap to speed searching.  The first level is
 633  * a bitset of words which contain pending event bits.  The second
 634  * level is a bitset of pending events themselves.
 635  */
 636 void xen_evtchn_do_upcall(struct pt_regs *regs)
 637 {
 638         int cpu = get_cpu();
 639         struct shared_info *s = HYPERVISOR_shared_info;
 640         struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
 641         static DEFINE_PER_CPU(unsigned, nesting_count);
 642         unsigned count;
 643
 644         do {
 645                 unsigned long pending_words;
 646
 647                 vcpu_info->evtchn_upcall_pending = 0;
 648
 649                 if (__get_cpu_var(nesting_count)++)
 650                         goto out;
 651
 652 #ifndef CONFIG_X86 /* No need for a barrier -- XCHG is a barrier on x86. */
 653                 /* Clear master flag /before/ clearing selector flag. */
 654                 wmb();
 655 #endif
 656                 pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
 657                 while (pending_words != 0) {
 658                         unsigned long pending_bits;
 659                         int word_idx = __ffs(pending_words);
 660                         pending_words &= ~(1UL << word_idx);
 661
 662                         while ((pending_bits = active_evtchns(cpu, s, word_idx)) != 0) {
 663                                 int bit_idx = __ffs(pending_bits);
 664                                 int port = (word_idx * BITS_PER_LONG) + bit_idx;
 665                                 int irq = evtchn_to_irq[port];
 666
 667                                 xen_do_irq(irq, regs);
 668                         }
 669                 }
 670
 671                 BUG_ON(!irqs_disabled());
 672
 673                 count = __get_cpu_var(nesting_count);
 674                 __get_cpu_var(nesting_count) = 0;
 675         } while(count != 1);
 676
 677 out:
 678         put_cpu();
 679 }
 680
 681 /* Rebind a new event channel to an existing irq. */
 682 void rebind_evtchn_irq(int evtchn, int irq)
 683 {
 684         /* Make sure the irq is masked, since the new event channel
 685            will also be masked. */
 686         disable_irq(irq);
 687
 688         spin_lock(&irq_mapping_update_lock);
 689
 690         /* After resume the irq<->evtchn mappings are all cleared out */
 691         BUG_ON(evtchn_to_irq[evtchn] != -1);
 692         /* Expect irq to have been bound before,
 693            so the bindcount should be non-0 */
 694         BUG_ON(irq_bindcount[irq] == 0);
 695
 696         evtchn_to_irq[evtchn] = irq;
 697         irq_info[irq] = mk_evtchn_info(evtchn);
 698
 699         spin_unlock(&irq_mapping_update_lock);
 700
 701         /* new event channels are always bound to cpu 0 */
 702         irq_set_affinity(irq, cpumask_of(0));
 703
 704         /* Unmask the event channel. */
 705         enable_irq(irq);
 706 }
 707
 708 /* Rebind an evtchn so that it gets delivered to a specific cpu */
 709 static void rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
 710 {
 711         struct evtchn_bind_vcpu bind_vcpu;
 712         int evtchn = evtchn_from_irq(irq);
 713
 714         if (!VALID_EVTCHN(evtchn))
 715                 return;
 716
 717         /* Send future instances of this interrupt to other vcpu. */
 718         bind_vcpu.port = evtchn;
 719         bind_vcpu.vcpu = tcpu;
 720
 721         /*
 722          * If this fails, it usually just indicates that we're dealing with a
 723          * virq or IPI channel, which don't actually need to be rebound. Ignore
 724          * it, but don't do the xenlinux-level rebind in that case.
 725          */
 726         if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
 727                 bind_evtchn_to_cpu(evtchn, tcpu);
 728 }
 729
 730
 731 static void set_affinity_irq(unsigned irq, const struct cpumask *dest)
 732 {
 733         unsigned tcpu = cpumask_first(dest);
 734         rebind_irq_to_cpu(irq, tcpu);
 735 }
 736
 737 int resend_irq_on_evtchn(unsigned int irq)
 738 {
 739         int masked, evtchn = evtchn_from_irq(irq);
 740         struct shared_info *s = HYPERVISOR_shared_info;
 741
 742         if (!VALID_EVTCHN(evtchn))
 743                 return 1;
 744
 745         masked = sync_test_and_set_bit(evtchn, s->evtchn_mask);
 746         sync_set_bit(evtchn, s->evtchn_pending);
 747         if (!masked)
 748                 unmask_evtchn(evtchn);
 749
 750         return 1;
 751 }
 752
 753 static void enable_dynirq(unsigned int irq)
 754 {
 755         int evtchn = evtchn_from_irq(irq);
 756
 757         if (VALID_EVTCHN(evtchn))
 758                 unmask_evtchn(evtchn);
 759 }
 760
 761 static void disable_dynirq(unsigned int irq)
 762 {
 763         int evtchn = evtchn_from_irq(irq);
 764
 765         if (VALID_EVTCHN(evtchn))
 766                 mask_evtchn(evtchn);
 767 }
 768
 769 static void ack_dynirq(unsigned int irq)
 770 {
 771         int evtchn = evtchn_from_irq(irq);
 772
 773         move_native_irq(irq);
 774
 775         if (VALID_EVTCHN(evtchn))
 776                 clear_evtchn(evtchn);
 777 }
 778
 779 static int retrigger_dynirq(unsigned int irq)
 780 {
 781         int evtchn = evtchn_from_irq(irq);
 782         struct shared_info *sh = HYPERVISOR_shared_info;
 783         int ret = 0;
 784
 785         if (VALID_EVTCHN(evtchn)) {
 786                 int masked;
 787
 788                 masked = sync_test_and_set_bit(evtchn, sh->evtchn_mask);
 789                 sync_set_bit(evtchn, sh->evtchn_pending);
 790                 if (!masked)
 791                         unmask_evtchn(evtchn);
 792                 ret = 1;
 793         }
 794
 795         return ret;
 796 }
 797
 798 static void restore_cpu_virqs(unsigned int cpu)
 799 {
 800         struct evtchn_bind_virq bind_virq;
 801         int virq, irq, evtchn;
 802
 803         for (virq = 0; virq < NR_VIRQS; virq++) {
 804                 if ((irq = per_cpu(virq_to_irq, cpu)[virq]) == -1)
 805                         continue;
 806
 807                 BUG_ON(virq_from_irq(irq) != virq);
 808
 809                 /* Get a new binding from Xen. */
 810                 bind_virq.virq = virq;
 811                 bind_virq.vcpu = cpu;
 812                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
 813                                                 &bind_virq) != 0)
 814                         BUG();
 815                 evtchn = bind_virq.port;
 816
 817                 /* Record the new mapping. */
 818                 evtchn_to_irq[evtchn] = irq;
 819                 irq_info[irq] = mk_virq_info(evtchn, virq);
 820                 bind_evtchn_to_cpu(evtchn, cpu);
 821
 822                 /* Ready for use. */
 823                 unmask_evtchn(evtchn);
 824         }
 825 }
 826
 827 static void restore_cpu_ipis(unsigned int cpu)
 828 {
 829         struct evtchn_bind_ipi bind_ipi;
 830         int ipi, irq, evtchn;
 831
 832         for (ipi = 0; ipi < XEN_NR_IPIS; ipi++) {
 833                 if ((irq = per_cpu(ipi_to_irq, cpu)[ipi]) == -1)
 834                         continue;
 835
 836                 BUG_ON(ipi_from_irq(irq) != ipi);
 837
 838                 /* Get a new binding from Xen. */
 839                 bind_ipi.vcpu = cpu;
 840                 if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
 841                                                 &bind_ipi) != 0)
 842                         BUG();
 843                 evtchn = bind_ipi.port;
 844
 845                 /* Record the new mapping. */
 846                 evtchn_to_irq[evtchn] = irq;
 847                 irq_info[irq] = mk_ipi_info(evtchn, ipi);
 848                 bind_evtchn_to_cpu(evtchn, cpu);
 849
 850                 /* Ready for use. */
 851                 unmask_evtchn(evtchn);
 852
 853         }
 854 }
 855
 856 /* Clear an irq's pending state, in preparation for polling on it */
 857 void xen_clear_irq_pending(int irq)
 858 {
 859         int evtchn = evtchn_from_irq(irq);
 860
 861         if (VALID_EVTCHN(evtchn))
 862                 clear_evtchn(evtchn);
 863 }
 864
 865 void xen_set_irq_pending(int irq)
 866 {
 867         int evtchn = evtchn_from_irq(irq);
 868
 869         if (VALID_EVTCHN(evtchn))
 870                 set_evtchn(evtchn);
 871 }
 872
 873 bool xen_test_irq_pending(int irq)
 874 {
 875         int evtchn = evtchn_from_irq(irq);
 876         bool ret = false;
 877
 878         if (VALID_EVTCHN(evtchn))
 879                 ret = test_evtchn(evtchn);
 880
 881         return ret;
 882 }
 883
 884 /* Poll waiting for an irq to become pending.  In the usual case, the
 885    irq will be disabled so it won't deliver an interrupt. */
 886 void xen_poll_irq(int irq)
 887 {
 888         evtchn_port_t evtchn = evtchn_from_irq(irq);
 889
 890         if (VALID_EVTCHN(evtchn)) {
 891                 struct sched_poll poll;
 892
 893                 poll.nr_ports = 1;
 894                 poll.timeout = 0;
 895                 set_xen_guest_handle(poll.ports, &evtchn);
 896
 897                 if (HYPERVISOR_sched_op(SCHEDOP_poll, &poll) != 0)
 898                         BUG();
 899         }
 900 }
 901
 902 void xen_irq_resume(void)
 903 {
 904         unsigned int cpu, irq, evtchn;
 905
 906         init_evtchn_cpu_bindings();
 907
 908         /* New event-channel space is not 'live' yet. */
 909         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
 910                 mask_evtchn(evtchn);
 911
 912         /* No IRQ <-> event-channel mappings. */
 913         for (irq = 0; irq < nr_irqs; irq++)
 914                 irq_info[irq].evtchn = 0; /* zap event-channel binding */
 915
 916         for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
 917                 evtchn_to_irq[evtchn] = -1;
 918
 919         for_each_possible_cpu(cpu) {
 920                 restore_cpu_virqs(cpu);
 921                 restore_cpu_ipis(cpu);
 922         }
 923 }
 924
 925 static struct irq_chip xen_dynamic_chip __read_mostly = {
 926         .name           = "xen-dyn",
 927
 928         .disable        = disable_dynirq,
 929         .mask           = disable_dynirq,
 930         .unmask         = enable_dynirq,
 931
 932         .ack            = ack_dynirq,
 933         .set_affinity   = set_affinity_irq,
 934         .retrigger      = retrigger_dynirq,
 935 };
 936
 937 void __init xen_init_IRQ(void)
 938 {
 939         int i;
 940         size_t size = nr_cpu_ids * sizeof(struct cpu_evtchn_s);
 941
 942         cpu_evtchn_mask_p = alloc_bootmem(size);
 943         BUG_ON(cpu_evtchn_mask_p == NULL);
 944
 945         init_evtchn_cpu_bindings();
 946
 947         /* No event channels are 'live' right now. */
 948         for (i = 0; i < NR_EVENT_CHANNELS; i++)
 949                 mask_evtchn(i);
 950
 951         /* Dynamic IRQ space is currently unbound. Zero the refcnts. */
 952         for (i = 0; i < nr_irqs; i++)
 953                 irq_bindcount[i] = 0;
 954
 955         irq_ctx_init(smp_processor_id());
 956 }