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