git.oblomov.eu Git - linux-2.6/blob - drivers/xen/events.c

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