linux/drivers/xen/events.c
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   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 received, 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. PIRQs - Hardware interrupts.
  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#include <linux/irqnr.h>
  32#include <linux/pci.h>
  33
  34#ifdef CONFIG_X86
  35#include <asm/desc.h>
  36#include <asm/ptrace.h>
  37#include <asm/irq.h>
  38#include <asm/idle.h>
  39#include <asm/io_apic.h>
  40#include <asm/xen/page.h>
  41#include <asm/xen/pci.h>
  42#endif
  43#include <asm/sync_bitops.h>
  44#include <asm/xen/hypercall.h>
  45#include <asm/xen/hypervisor.h>
  46
  47#include <xen/xen.h>
  48#include <xen/hvm.h>
  49#include <xen/xen-ops.h>
  50#include <xen/events.h>
  51#include <xen/interface/xen.h>
  52#include <xen/interface/event_channel.h>
  53#include <xen/interface/hvm/hvm_op.h>
  54#include <xen/interface/hvm/params.h>
  55#include <xen/interface/physdev.h>
  56#include <xen/interface/sched.h>
  57#include <asm/hw_irq.h>
  58
  59/*
  60 * This lock protects updates to the following mapping and reference-count
  61 * arrays. The lock does not need to be acquired to read the mapping tables.
  62 */
  63static DEFINE_MUTEX(irq_mapping_update_lock);
  64
  65static LIST_HEAD(xen_irq_list_head);
  66
  67/* IRQ <-> VIRQ mapping. */
  68static DEFINE_PER_CPU(int [NR_VIRQS], virq_to_irq) = {[0 ... NR_VIRQS-1] = -1};
  69
  70/* IRQ <-> IPI mapping */
  71static DEFINE_PER_CPU(int [XEN_NR_IPIS], ipi_to_irq) = {[0 ... XEN_NR_IPIS-1] = -1};
  72
  73/* Interrupt types. */
  74enum xen_irq_type {
  75        IRQT_UNBOUND = 0,
  76        IRQT_PIRQ,
  77        IRQT_VIRQ,
  78        IRQT_IPI,
  79        IRQT_EVTCHN
  80};
  81
  82/*
  83 * Packed IRQ information:
  84 * type - enum xen_irq_type
  85 * event channel - irq->event channel mapping
  86 * cpu - cpu this event channel is bound to
  87 * index - type-specific information:
  88 *    PIRQ - vector, with MSB being "needs EIO", or physical IRQ of the HVM
  89 *           guest, or GSI (real passthrough IRQ) of the device.
  90 *    VIRQ - virq number
  91 *    IPI - IPI vector
  92 *    EVTCHN -
  93 */
  94struct irq_info {
  95        struct list_head list;
  96        int refcnt;
  97        enum xen_irq_type type; /* type */
  98        unsigned irq;
  99        unsigned short evtchn;  /* event channel */
 100        unsigned short cpu;     /* cpu bound */
 101
 102        union {
 103                unsigned short virq;
 104                enum ipi_vector ipi;
 105                struct {
 106                        unsigned short pirq;
 107                        unsigned short gsi;
 108                        unsigned char vector;
 109                        unsigned char flags;
 110                        uint16_t domid;
 111                } pirq;
 112        } u;
 113};
 114#define PIRQ_NEEDS_EOI  (1 << 0)
 115#define PIRQ_SHAREABLE  (1 << 1)
 116
 117static int *evtchn_to_irq;
 118#ifdef CONFIG_X86
 119static unsigned long *pirq_eoi_map;
 120#endif
 121static bool (*pirq_needs_eoi)(unsigned irq);
 122
 123static DEFINE_PER_CPU(unsigned long [NR_EVENT_CHANNELS/BITS_PER_LONG],
 124                      cpu_evtchn_mask);
 125
 126/* Xen will never allocate port zero for any purpose. */
 127#define VALID_EVTCHN(chn)       ((chn) != 0)
 128
 129static struct irq_chip xen_dynamic_chip;
 130static struct irq_chip xen_percpu_chip;
 131static struct irq_chip xen_pirq_chip;
 132static void enable_dynirq(struct irq_data *data);
 133static void disable_dynirq(struct irq_data *data);
 134
 135/* Get info for IRQ */
 136static struct irq_info *info_for_irq(unsigned irq)
 137{
 138        return irq_get_handler_data(irq);
 139}
 140
 141/* Constructors for packed IRQ information. */
 142static void xen_irq_info_common_init(struct irq_info *info,
 143                                     unsigned irq,
 144                                     enum xen_irq_type type,
 145                                     unsigned short evtchn,
 146                                     unsigned short cpu)
 147{
 148
 149        BUG_ON(info->type != IRQT_UNBOUND && info->type != type);
 150
 151        info->type = type;
 152        info->irq = irq;
 153        info->evtchn = evtchn;
 154        info->cpu = cpu;
 155
 156        evtchn_to_irq[evtchn] = irq;
 157}
 158
 159static void xen_irq_info_evtchn_init(unsigned irq,
 160                                     unsigned short evtchn)
 161{
 162        struct irq_info *info = info_for_irq(irq);
 163
 164        xen_irq_info_common_init(info, irq, IRQT_EVTCHN, evtchn, 0);
 165}
 166
 167static void xen_irq_info_ipi_init(unsigned cpu,
 168                                  unsigned irq,
 169                                  unsigned short evtchn,
 170                                  enum ipi_vector ipi)
 171{
 172        struct irq_info *info = info_for_irq(irq);
 173
 174        xen_irq_info_common_init(info, irq, IRQT_IPI, evtchn, 0);
 175
 176        info->u.ipi = ipi;
 177
 178        per_cpu(ipi_to_irq, cpu)[ipi] = irq;
 179}
 180
 181static void xen_irq_info_virq_init(unsigned cpu,
 182                                   unsigned irq,
 183                                   unsigned short evtchn,
 184                                   unsigned short virq)
 185{
 186        struct irq_info *info = info_for_irq(irq);
 187
 188        xen_irq_info_common_init(info, irq, IRQT_VIRQ, evtchn, 0);
 189
 190        info->u.virq = virq;
 191
 192        per_cpu(virq_to_irq, cpu)[virq] = irq;
 193}
 194
 195static void xen_irq_info_pirq_init(unsigned irq,
 196                                   unsigned short evtchn,
 197                                   unsigned short pirq,
 198                                   unsigned short gsi,
 199                                   unsigned short vector,
 200                                   uint16_t domid,
 201                                   unsigned char flags)
 202{
 203        struct irq_info *info = info_for_irq(irq);
 204
 205        xen_irq_info_common_init(info, irq, IRQT_PIRQ, evtchn, 0);
 206
 207        info->u.pirq.pirq = pirq;
 208        info->u.pirq.gsi = gsi;
 209        info->u.pirq.vector = vector;
 210        info->u.pirq.domid = domid;
 211        info->u.pirq.flags = flags;
 212}
 213
 214/*
 215 * Accessors for packed IRQ information.
 216 */
 217static unsigned int evtchn_from_irq(unsigned irq)
 218{
 219        if (unlikely(WARN(irq < 0 || irq >= nr_irqs, "Invalid irq %d!\n", irq)))
 220                return 0;
 221
 222        return info_for_irq(irq)->evtchn;
 223}
 224
 225unsigned irq_from_evtchn(unsigned int evtchn)
 226{
 227        return evtchn_to_irq[evtchn];
 228}
 229EXPORT_SYMBOL_GPL(irq_from_evtchn);
 230
 231static enum ipi_vector ipi_from_irq(unsigned irq)
 232{
 233        struct irq_info *info = info_for_irq(irq);
 234
 235        BUG_ON(info == NULL);
 236        BUG_ON(info->type != IRQT_IPI);
 237
 238        return info->u.ipi;
 239}
 240
 241static unsigned virq_from_irq(unsigned irq)
 242{
 243        struct irq_info *info = info_for_irq(irq);
 244
 245        BUG_ON(info == NULL);
 246        BUG_ON(info->type != IRQT_VIRQ);
 247
 248        return info->u.virq;
 249}
 250
 251static unsigned pirq_from_irq(unsigned irq)
 252{
 253        struct irq_info *info = info_for_irq(irq);
 254
 255        BUG_ON(info == NULL);
 256        BUG_ON(info->type != IRQT_PIRQ);
 257
 258        return info->u.pirq.pirq;
 259}
 260
 261static enum xen_irq_type type_from_irq(unsigned irq)
 262{
 263        return info_for_irq(irq)->type;
 264}
 265
 266static unsigned cpu_from_irq(unsigned irq)
 267{
 268        return info_for_irq(irq)->cpu;
 269}
 270
 271static unsigned int cpu_from_evtchn(unsigned int evtchn)
 272{
 273        int irq = evtchn_to_irq[evtchn];
 274        unsigned ret = 0;
 275
 276        if (irq != -1)
 277                ret = cpu_from_irq(irq);
 278
 279        return ret;
 280}
 281
 282#ifdef CONFIG_X86
 283static bool pirq_check_eoi_map(unsigned irq)
 284{
 285        return test_bit(pirq_from_irq(irq), pirq_eoi_map);
 286}
 287#endif
 288
 289static bool pirq_needs_eoi_flag(unsigned irq)
 290{
 291        struct irq_info *info = info_for_irq(irq);
 292        BUG_ON(info->type != IRQT_PIRQ);
 293
 294        return info->u.pirq.flags & PIRQ_NEEDS_EOI;
 295}
 296
 297static inline unsigned long active_evtchns(unsigned int cpu,
 298                                           struct shared_info *sh,
 299                                           unsigned int idx)
 300{
 301        return sh->evtchn_pending[idx] &
 302                per_cpu(cpu_evtchn_mask, cpu)[idx] &
 303                ~sh->evtchn_mask[idx];
 304}
 305
 306static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
 307{
 308        int irq = evtchn_to_irq[chn];
 309
 310        BUG_ON(irq == -1);
 311#ifdef CONFIG_SMP
 312        cpumask_copy(irq_to_desc(irq)->irq_data.affinity, cpumask_of(cpu));
 313#endif
 314
 315        clear_bit(chn, per_cpu(cpu_evtchn_mask, cpu_from_irq(irq)));
 316        set_bit(chn, per_cpu(cpu_evtchn_mask, cpu));
 317
 318        info_for_irq(irq)->cpu = cpu;
 319}
 320
 321static void init_evtchn_cpu_bindings(void)
 322{
 323        int i;
 324#ifdef CONFIG_SMP
 325        struct irq_info *info;
 326
 327        /* By default all event channels notify CPU#0. */
 328        list_for_each_entry(info, &xen_irq_list_head, list) {
 329                struct irq_desc *desc = irq_to_desc(info->irq);
 330                cpumask_copy(desc->irq_data.affinity, cpumask_of(0));
 331        }
 332#endif
 333
 334        for_each_possible_cpu(i)
 335                memset(per_cpu(cpu_evtchn_mask, i),
 336                       (i == 0) ? ~0 : 0, sizeof(*per_cpu(cpu_evtchn_mask, i)));
 337}
 338
 339static inline void clear_evtchn(int port)
 340{
 341        struct shared_info *s = HYPERVISOR_shared_info;
 342        sync_clear_bit(port, &s->evtchn_pending[0]);
 343}
 344
 345static inline void set_evtchn(int port)
 346{
 347        struct shared_info *s = HYPERVISOR_shared_info;
 348        sync_set_bit(port, &s->evtchn_pending[0]);
 349}
 350
 351static inline int test_evtchn(int port)
 352{
 353        struct shared_info *s = HYPERVISOR_shared_info;
 354        return sync_test_bit(port, &s->evtchn_pending[0]);
 355}
 356
 357
 358/**
 359 * notify_remote_via_irq - send event to remote end of event channel via irq
 360 * @irq: irq of event channel to send event to
 361 *
 362 * Unlike notify_remote_via_evtchn(), this is safe to use across
 363 * save/restore. Notifications on a broken connection are silently
 364 * dropped.
 365 */
 366void notify_remote_via_irq(int irq)
 367{
 368        int evtchn = evtchn_from_irq(irq);
 369
 370        if (VALID_EVTCHN(evtchn))
 371                notify_remote_via_evtchn(evtchn);
 372}
 373EXPORT_SYMBOL_GPL(notify_remote_via_irq);
 374
 375static void mask_evtchn(int port)
 376{
 377        struct shared_info *s = HYPERVISOR_shared_info;
 378        sync_set_bit(port, &s->evtchn_mask[0]);
 379}
 380
 381static void unmask_evtchn(int port)
 382{
 383        struct shared_info *s = HYPERVISOR_shared_info;
 384        unsigned int cpu = get_cpu();
 385        int do_hypercall = 0, evtchn_pending = 0;
 386
 387        BUG_ON(!irqs_disabled());
 388
 389        if (unlikely((cpu != cpu_from_evtchn(port))))
 390                do_hypercall = 1;
 391        else
 392                evtchn_pending = sync_test_bit(port, &s->evtchn_pending[0]);
 393
 394        if (unlikely(evtchn_pending && xen_hvm_domain()))
 395                do_hypercall = 1;
 396
 397        /* Slow path (hypercall) if this is a non-local port or if this is
 398         * an hvm domain and an event is pending (hvm domains don't have
 399         * their own implementation of irq_enable). */
 400        if (do_hypercall) {
 401                struct evtchn_unmask unmask = { .port = port };
 402                (void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask);
 403        } else {
 404                struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
 405
 406                sync_clear_bit(port, &s->evtchn_mask[0]);
 407
 408                /*
 409                 * The following is basically the equivalent of
 410                 * 'hw_resend_irq'. Just like a real IO-APIC we 'lose
 411                 * the interrupt edge' if the channel is masked.
 412                 */
 413                if (evtchn_pending &&
 414                    !sync_test_and_set_bit(port / BITS_PER_LONG,
 415                                           &vcpu_info->evtchn_pending_sel))
 416                        vcpu_info->evtchn_upcall_pending = 1;
 417        }
 418
 419        put_cpu();
 420}
 421
 422static void xen_irq_init(unsigned irq)
 423{
 424        struct irq_info *info;
 425#ifdef CONFIG_SMP
 426        struct irq_desc *desc = irq_to_desc(irq);
 427
 428        /* By default all event channels notify CPU#0. */
 429        cpumask_copy(desc->irq_data.affinity, cpumask_of(0));
 430#endif
 431
 432        info = kzalloc(sizeof(*info), GFP_KERNEL);
 433        if (info == NULL)
 434                panic("Unable to allocate metadata for IRQ%d\n", irq);
 435
 436        info->type = IRQT_UNBOUND;
 437        info->refcnt = -1;
 438
 439        irq_set_handler_data(irq, info);
 440
 441        list_add_tail(&info->list, &xen_irq_list_head);
 442}
 443
 444static int __must_check xen_allocate_irq_dynamic(void)
 445{
 446        int first = 0;
 447        int irq;
 448
 449#ifdef CONFIG_X86_IO_APIC
 450        /*
 451         * For an HVM guest or domain 0 which see "real" (emulated or
 452         * actual respectively) GSIs we allocate dynamic IRQs
 453         * e.g. those corresponding to event channels or MSIs
 454         * etc. from the range above those "real" GSIs to avoid
 455         * collisions.
 456         */
 457        if (xen_initial_domain() || xen_hvm_domain())
 458                first = get_nr_irqs_gsi();
 459#endif
 460
 461        irq = irq_alloc_desc_from(first, -1);
 462
 463        if (irq >= 0)
 464                xen_irq_init(irq);
 465
 466        return irq;
 467}
 468
 469static int __must_check xen_allocate_irq_gsi(unsigned gsi)
 470{
 471        int irq;
 472
 473        /*
 474         * A PV guest has no concept of a GSI (since it has no ACPI
 475         * nor access to/knowledge of the physical APICs). Therefore
 476         * all IRQs are dynamically allocated from the entire IRQ
 477         * space.
 478         */
 479        if (xen_pv_domain() && !xen_initial_domain())
 480                return xen_allocate_irq_dynamic();
 481
 482        /* Legacy IRQ descriptors are already allocated by the arch. */
 483        if (gsi < NR_IRQS_LEGACY)
 484                irq = gsi;
 485        else
 486                irq = irq_alloc_desc_at(gsi, -1);
 487
 488        xen_irq_init(irq);
 489
 490        return irq;
 491}
 492
 493static void xen_free_irq(unsigned irq)
 494{
 495        struct irq_info *info = irq_get_handler_data(irq);
 496
 497        list_del(&info->list);
 498
 499        irq_set_handler_data(irq, NULL);
 500
 501        WARN_ON(info->refcnt > 0);
 502
 503        kfree(info);
 504
 505        /* Legacy IRQ descriptors are managed by the arch. */
 506        if (irq < NR_IRQS_LEGACY)
 507                return;
 508
 509        irq_free_desc(irq);
 510}
 511
 512static void pirq_query_unmask(int irq)
 513{
 514        struct physdev_irq_status_query irq_status;
 515        struct irq_info *info = info_for_irq(irq);
 516
 517        BUG_ON(info->type != IRQT_PIRQ);
 518
 519        irq_status.irq = pirq_from_irq(irq);
 520        if (HYPERVISOR_physdev_op(PHYSDEVOP_irq_status_query, &irq_status))
 521                irq_status.flags = 0;
 522
 523        info->u.pirq.flags &= ~PIRQ_NEEDS_EOI;
 524        if (irq_status.flags & XENIRQSTAT_needs_eoi)
 525                info->u.pirq.flags |= PIRQ_NEEDS_EOI;
 526}
 527
 528static bool probing_irq(int irq)
 529{
 530        struct irq_desc *desc = irq_to_desc(irq);
 531
 532        return desc && desc->action == NULL;
 533}
 534
 535static void eoi_pirq(struct irq_data *data)
 536{
 537        int evtchn = evtchn_from_irq(data->irq);
 538        struct physdev_eoi eoi = { .irq = pirq_from_irq(data->irq) };
 539        int rc = 0;
 540
 541        irq_move_irq(data);
 542
 543        if (VALID_EVTCHN(evtchn))
 544                clear_evtchn(evtchn);
 545
 546        if (pirq_needs_eoi(data->irq)) {
 547                rc = HYPERVISOR_physdev_op(PHYSDEVOP_eoi, &eoi);
 548                WARN_ON(rc);
 549        }
 550}
 551
 552static void mask_ack_pirq(struct irq_data *data)
 553{
 554        disable_dynirq(data);
 555        eoi_pirq(data);
 556}
 557
 558static unsigned int __startup_pirq(unsigned int irq)
 559{
 560        struct evtchn_bind_pirq bind_pirq;
 561        struct irq_info *info = info_for_irq(irq);
 562        int evtchn = evtchn_from_irq(irq);
 563        int rc;
 564
 565        BUG_ON(info->type != IRQT_PIRQ);
 566
 567        if (VALID_EVTCHN(evtchn))
 568                goto out;
 569
 570        bind_pirq.pirq = pirq_from_irq(irq);
 571        /* NB. We are happy to share unless we are probing. */
 572        bind_pirq.flags = info->u.pirq.flags & PIRQ_SHAREABLE ?
 573                                        BIND_PIRQ__WILL_SHARE : 0;
 574        rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_pirq, &bind_pirq);
 575        if (rc != 0) {
 576                if (!probing_irq(irq))
 577                        printk(KERN_INFO "Failed to obtain physical IRQ %d\n",
 578                               irq);
 579                return 0;
 580        }
 581        evtchn = bind_pirq.port;
 582
 583        pirq_query_unmask(irq);
 584
 585        evtchn_to_irq[evtchn] = irq;
 586        bind_evtchn_to_cpu(evtchn, 0);
 587        info->evtchn = evtchn;
 588
 589out:
 590        unmask_evtchn(evtchn);
 591        eoi_pirq(irq_get_irq_data(irq));
 592
 593        return 0;
 594}
 595
 596static unsigned int startup_pirq(struct irq_data *data)
 597{
 598        return __startup_pirq(data->irq);
 599}
 600
 601static void shutdown_pirq(struct irq_data *data)
 602{
 603        struct evtchn_close close;
 604        unsigned int irq = data->irq;
 605        struct irq_info *info = info_for_irq(irq);
 606        int evtchn = evtchn_from_irq(irq);
 607
 608        BUG_ON(info->type != IRQT_PIRQ);
 609
 610        if (!VALID_EVTCHN(evtchn))
 611                return;
 612
 613        mask_evtchn(evtchn);
 614
 615        close.port = evtchn;
 616        if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
 617                BUG();
 618
 619        bind_evtchn_to_cpu(evtchn, 0);
 620        evtchn_to_irq[evtchn] = -1;
 621        info->evtchn = 0;
 622}
 623
 624static void enable_pirq(struct irq_data *data)
 625{
 626        startup_pirq(data);
 627}
 628
 629static void disable_pirq(struct irq_data *data)
 630{
 631        disable_dynirq(data);
 632}
 633
 634int xen_irq_from_gsi(unsigned gsi)
 635{
 636        struct irq_info *info;
 637
 638        list_for_each_entry(info, &xen_irq_list_head, list) {
 639                if (info->type != IRQT_PIRQ)
 640                        continue;
 641
 642                if (info->u.pirq.gsi == gsi)
 643                        return info->irq;
 644        }
 645
 646        return -1;
 647}
 648EXPORT_SYMBOL_GPL(xen_irq_from_gsi);
 649
 650/*
 651 * Do not make any assumptions regarding the relationship between the
 652 * IRQ number returned here and the Xen pirq argument.
 653 *
 654 * Note: We don't assign an event channel until the irq actually started
 655 * up.  Return an existing irq if we've already got one for the gsi.
 656 *
 657 * Shareable implies level triggered, not shareable implies edge
 658 * triggered here.
 659 */
 660int xen_bind_pirq_gsi_to_irq(unsigned gsi,
 661                             unsigned pirq, int shareable, char *name)
 662{
 663        int irq = -1;
 664        struct physdev_irq irq_op;
 665
 666        mutex_lock(&irq_mapping_update_lock);
 667
 668        irq = xen_irq_from_gsi(gsi);
 669        if (irq != -1) {
 670                printk(KERN_INFO "xen_map_pirq_gsi: returning irq %d for gsi %u\n",
 671                       irq, gsi);
 672                goto out;
 673        }
 674
 675        irq = xen_allocate_irq_gsi(gsi);
 676        if (irq < 0)
 677                goto out;
 678
 679        irq_op.irq = irq;
 680        irq_op.vector = 0;
 681
 682        /* Only the privileged domain can do this. For non-priv, the pcifront
 683         * driver provides a PCI bus that does the call to do exactly
 684         * this in the priv domain. */
 685        if (xen_initial_domain() &&
 686            HYPERVISOR_physdev_op(PHYSDEVOP_alloc_irq_vector, &irq_op)) {
 687                xen_free_irq(irq);
 688                irq = -ENOSPC;
 689                goto out;
 690        }
 691
 692        xen_irq_info_pirq_init(irq, 0, pirq, gsi, irq_op.vector, DOMID_SELF,
 693                               shareable ? PIRQ_SHAREABLE : 0);
 694
 695        pirq_query_unmask(irq);
 696        /* We try to use the handler with the appropriate semantic for the
 697         * type of interrupt: if the interrupt is an edge triggered
 698         * interrupt we use handle_edge_irq.
 699         *
 700         * On the other hand if the interrupt is level triggered we use
 701         * handle_fasteoi_irq like the native code does for this kind of
 702         * interrupts.
 703         *
 704         * Depending on the Xen version, pirq_needs_eoi might return true
 705         * not only for level triggered interrupts but for edge triggered
 706         * interrupts too. In any case Xen always honors the eoi mechanism,
 707         * not injecting any more pirqs of the same kind if the first one
 708         * hasn't received an eoi yet. Therefore using the fasteoi handler
 709         * is the right choice either way.
 710         */
 711        if (shareable)
 712                irq_set_chip_and_handler_name(irq, &xen_pirq_chip,
 713                                handle_fasteoi_irq, name);
 714        else
 715                irq_set_chip_and_handler_name(irq, &xen_pirq_chip,
 716                                handle_edge_irq, name);
 717
 718out:
 719        mutex_unlock(&irq_mapping_update_lock);
 720
 721        return irq;
 722}
 723
 724#ifdef CONFIG_PCI_MSI
 725int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc)
 726{
 727        int rc;
 728        struct physdev_get_free_pirq op_get_free_pirq;
 729
 730        op_get_free_pirq.type = MAP_PIRQ_TYPE_MSI;
 731        rc = HYPERVISOR_physdev_op(PHYSDEVOP_get_free_pirq, &op_get_free_pirq);
 732
 733        WARN_ONCE(rc == -ENOSYS,
 734                  "hypervisor does not support the PHYSDEVOP_get_free_pirq interface\n");
 735
 736        return rc ? -1 : op_get_free_pirq.pirq;
 737}
 738
 739int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
 740                             int pirq, int vector, const char *name,
 741                             domid_t domid)
 742{
 743        int irq, ret;
 744
 745        mutex_lock(&irq_mapping_update_lock);
 746
 747        irq = xen_allocate_irq_dynamic();
 748        if (irq < 0)
 749                goto out;
 750
 751        irq_set_chip_and_handler_name(irq, &xen_pirq_chip, handle_edge_irq,
 752                        name);
 753
 754        xen_irq_info_pirq_init(irq, 0, pirq, 0, vector, domid, 0);
 755        ret = irq_set_msi_desc(irq, msidesc);
 756        if (ret < 0)
 757                goto error_irq;
 758out:
 759        mutex_unlock(&irq_mapping_update_lock);
 760        return irq;
 761error_irq:
 762        mutex_unlock(&irq_mapping_update_lock);
 763        xen_free_irq(irq);
 764        return ret;
 765}
 766#endif
 767
 768int xen_destroy_irq(int irq)
 769{
 770        struct irq_desc *desc;
 771        struct physdev_unmap_pirq unmap_irq;
 772        struct irq_info *info = info_for_irq(irq);
 773        int rc = -ENOENT;
 774
 775        mutex_lock(&irq_mapping_update_lock);
 776
 777        desc = irq_to_desc(irq);
 778        if (!desc)
 779                goto out;
 780
 781        if (xen_initial_domain()) {
 782                unmap_irq.pirq = info->u.pirq.pirq;
 783                unmap_irq.domid = info->u.pirq.domid;
 784                rc = HYPERVISOR_physdev_op(PHYSDEVOP_unmap_pirq, &unmap_irq);
 785                /* If another domain quits without making the pci_disable_msix
 786                 * call, the Xen hypervisor takes care of freeing the PIRQs
 787                 * (free_domain_pirqs).
 788                 */
 789                if ((rc == -ESRCH && info->u.pirq.domid != DOMID_SELF))
 790                        printk(KERN_INFO "domain %d does not have %d anymore\n",
 791                                info->u.pirq.domid, info->u.pirq.pirq);
 792                else if (rc) {
 793                        printk(KERN_WARNING "unmap irq failed %d\n", rc);
 794                        goto out;
 795                }
 796        }
 797
 798        xen_free_irq(irq);
 799
 800out:
 801        mutex_unlock(&irq_mapping_update_lock);
 802        return rc;
 803}
 804
 805int xen_irq_from_pirq(unsigned pirq)
 806{
 807        int irq;
 808
 809        struct irq_info *info;
 810
 811        mutex_lock(&irq_mapping_update_lock);
 812
 813        list_for_each_entry(info, &xen_irq_list_head, list) {
 814                if (info->type != IRQT_PIRQ)
 815                        continue;
 816                irq = info->irq;
 817                if (info->u.pirq.pirq == pirq)
 818                        goto out;
 819        }
 820        irq = -1;
 821out:
 822        mutex_unlock(&irq_mapping_update_lock);
 823
 824        return irq;
 825}
 826
 827
 828int xen_pirq_from_irq(unsigned irq)
 829{
 830        return pirq_from_irq(irq);
 831}
 832EXPORT_SYMBOL_GPL(xen_pirq_from_irq);
 833int bind_evtchn_to_irq(unsigned int evtchn)
 834{
 835        int irq;
 836
 837        mutex_lock(&irq_mapping_update_lock);
 838
 839        irq = evtchn_to_irq[evtchn];
 840
 841        if (irq == -1) {
 842                irq = xen_allocate_irq_dynamic();
 843                if (irq == -1)
 844                        goto out;
 845
 846                irq_set_chip_and_handler_name(irq, &xen_dynamic_chip,
 847                                              handle_edge_irq, "event");
 848
 849                xen_irq_info_evtchn_init(irq, evtchn);
 850        } else {
 851                struct irq_info *info = info_for_irq(irq);
 852                WARN_ON(info == NULL || info->type != IRQT_EVTCHN);
 853        }
 854        irq_clear_status_flags(irq, IRQ_NOREQUEST|IRQ_NOAUTOEN);
 855
 856out:
 857        mutex_unlock(&irq_mapping_update_lock);
 858
 859        return irq;
 860}
 861EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);
 862
 863static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
 864{
 865        struct evtchn_bind_ipi bind_ipi;
 866        int evtchn, irq;
 867
 868        mutex_lock(&irq_mapping_update_lock);
 869
 870        irq = per_cpu(ipi_to_irq, cpu)[ipi];
 871
 872        if (irq == -1) {
 873                irq = xen_allocate_irq_dynamic();
 874                if (irq < 0)
 875                        goto out;
 876
 877                irq_set_chip_and_handler_name(irq, &xen_percpu_chip,
 878                                              handle_percpu_irq, "ipi");
 879
 880                bind_ipi.vcpu = cpu;
 881                if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
 882                                                &bind_ipi) != 0)
 883                        BUG();
 884                evtchn = bind_ipi.port;
 885
 886                xen_irq_info_ipi_init(cpu, irq, evtchn, ipi);
 887
 888                bind_evtchn_to_cpu(evtchn, cpu);
 889        } else {
 890                struct irq_info *info = info_for_irq(irq);
 891                WARN_ON(info == NULL || info->type != IRQT_IPI);
 892        }
 893
 894 out:
 895        mutex_unlock(&irq_mapping_update_lock);
 896        return irq;
 897}
 898
 899static int bind_interdomain_evtchn_to_irq(unsigned int remote_domain,
 900                                          unsigned int remote_port)
 901{
 902        struct evtchn_bind_interdomain bind_interdomain;
 903        int err;
 904
 905        bind_interdomain.remote_dom  = remote_domain;
 906        bind_interdomain.remote_port = remote_port;
 907
 908        err = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain,
 909                                          &bind_interdomain);
 910
 911        return err ? : bind_evtchn_to_irq(bind_interdomain.local_port);
 912}
 913
 914static int find_virq(unsigned int virq, unsigned int cpu)
 915{
 916        struct evtchn_status status;
 917        int port, rc = -ENOENT;
 918
 919        memset(&status, 0, sizeof(status));
 920        for (port = 0; port <= NR_EVENT_CHANNELS; port++) {
 921                status.dom = DOMID_SELF;
 922                status.port = port;
 923                rc = HYPERVISOR_event_channel_op(EVTCHNOP_status, &status);
 924                if (rc < 0)
 925                        continue;
 926                if (status.status != EVTCHNSTAT_virq)
 927                        continue;
 928                if (status.u.virq == virq && status.vcpu == cpu) {
 929                        rc = port;
 930                        break;
 931                }
 932        }
 933        return rc;
 934}
 935
 936int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 937{
 938        struct evtchn_bind_virq bind_virq;
 939        int evtchn, irq, ret;
 940
 941        mutex_lock(&irq_mapping_update_lock);
 942
 943        irq = per_cpu(virq_to_irq, cpu)[virq];
 944
 945        if (irq == -1) {
 946                irq = xen_allocate_irq_dynamic();
 947                if (irq == -1)
 948                        goto out;
 949
 950                irq_set_chip_and_handler_name(irq, &xen_percpu_chip,
 951                                              handle_percpu_irq, "virq");
 952
 953                bind_virq.virq = virq;
 954                bind_virq.vcpu = cpu;
 955                ret = HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
 956                                                &bind_virq);
 957                if (ret == 0)
 958                        evtchn = bind_virq.port;
 959                else {
 960                        if (ret == -EEXIST)
 961                                ret = find_virq(virq, cpu);
 962                        BUG_ON(ret < 0);
 963                        evtchn = ret;
 964                }
 965
 966                xen_irq_info_virq_init(cpu, irq, evtchn, virq);
 967
 968                bind_evtchn_to_cpu(evtchn, cpu);
 969        } else {
 970                struct irq_info *info = info_for_irq(irq);
 971                WARN_ON(info == NULL || info->type != IRQT_VIRQ);
 972        }
 973
 974out:
 975        mutex_unlock(&irq_mapping_update_lock);
 976
 977        return irq;
 978}
 979
 980static void unbind_from_irq(unsigned int irq)
 981{
 982        struct evtchn_close close;
 983        int evtchn = evtchn_from_irq(irq);
 984        struct irq_info *info = irq_get_handler_data(irq);
 985
 986        mutex_lock(&irq_mapping_update_lock);
 987
 988        if (info->refcnt > 0) {
 989                info->refcnt--;
 990                if (info->refcnt != 0)
 991                        goto done;
 992        }
 993
 994        if (VALID_EVTCHN(evtchn)) {
 995                close.port = evtchn;
 996                if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
 997                        BUG();
 998
 999                switch (type_from_irq(irq)) {
1000                case IRQT_VIRQ:
1001                        per_cpu(virq_to_irq, cpu_from_evtchn(evtchn))
1002                                [virq_from_irq(irq)] = -1;
1003                        break;
1004                case IRQT_IPI:
1005                        per_cpu(ipi_to_irq, cpu_from_evtchn(evtchn))
1006                                [ipi_from_irq(irq)] = -1;
1007                        break;
1008                default:
1009                        break;
1010                }
1011
1012                /* Closed ports are implicitly re-bound to VCPU0. */
1013                bind_evtchn_to_cpu(evtchn, 0);
1014
1015                evtchn_to_irq[evtchn] = -1;
1016        }
1017
1018        BUG_ON(info_for_irq(irq)->type == IRQT_UNBOUND);
1019
1020        xen_free_irq(irq);
1021
1022 done:
1023        mutex_unlock(&irq_mapping_update_lock);
1024}
1025
1026int bind_evtchn_to_irqhandler(unsigned int evtchn,
1027                              irq_handler_t handler,
1028                              unsigned long irqflags,
1029                              const char *devname, void *dev_id)
1030{
1031        int irq, retval;
1032
1033        irq = bind_evtchn_to_irq(evtchn);
1034        if (irq < 0)
1035                return irq;
1036        retval = request_irq(irq, handler, irqflags, devname, dev_id);
1037        if (retval != 0) {
1038                unbind_from_irq(irq);
1039                return retval;
1040        }
1041
1042        return irq;
1043}
1044EXPORT_SYMBOL_GPL(bind_evtchn_to_irqhandler);
1045
1046int bind_interdomain_evtchn_to_irqhandler(unsigned int remote_domain,
1047                                          unsigned int remote_port,
1048                                          irq_handler_t handler,
1049                                          unsigned long irqflags,
1050                                          const char *devname,
1051                                          void *dev_id)
1052{
1053        int irq, retval;
1054
1055        irq = bind_interdomain_evtchn_to_irq(remote_domain, remote_port);
1056        if (irq < 0)
1057                return irq;
1058
1059        retval = request_irq(irq, handler, irqflags, devname, dev_id);
1060        if (retval != 0) {
1061                unbind_from_irq(irq);
1062                return retval;
1063        }
1064
1065        return irq;
1066}
1067EXPORT_SYMBOL_GPL(bind_interdomain_evtchn_to_irqhandler);
1068
1069int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
1070                            irq_handler_t handler,
1071                            unsigned long irqflags, const char *devname, void *dev_id)
1072{
1073        int irq, retval;
1074
1075        irq = bind_virq_to_irq(virq, cpu);
1076        if (irq < 0)
1077                return irq;
1078        retval = request_irq(irq, handler, irqflags, devname, dev_id);
1079        if (retval != 0) {
1080                unbind_from_irq(irq);
1081                return retval;
1082        }
1083
1084        return irq;
1085}
1086EXPORT_SYMBOL_GPL(bind_virq_to_irqhandler);
1087
1088int bind_ipi_to_irqhandler(enum ipi_vector ipi,
1089                           unsigned int cpu,
1090                           irq_handler_t handler,
1091                           unsigned long irqflags,
1092                           const char *devname,
1093                           void *dev_id)
1094{
1095        int irq, retval;
1096
1097        irq = bind_ipi_to_irq(ipi, cpu);
1098        if (irq < 0)
1099                return irq;
1100
1101        irqflags |= IRQF_NO_SUSPEND | IRQF_FORCE_RESUME | IRQF_EARLY_RESUME;
1102        retval = request_irq(irq, handler, irqflags, devname, dev_id);
1103        if (retval != 0) {
1104                unbind_from_irq(irq);
1105                return retval;
1106        }
1107
1108        return irq;
1109}
1110
1111void unbind_from_irqhandler(unsigned int irq, void *dev_id)
1112{
1113        free_irq(irq, dev_id);
1114        unbind_from_irq(irq);
1115}
1116EXPORT_SYMBOL_GPL(unbind_from_irqhandler);
1117
1118int evtchn_make_refcounted(unsigned int evtchn)
1119{
1120        int irq = evtchn_to_irq[evtchn];
1121        struct irq_info *info;
1122
1123        if (irq == -1)
1124                return -ENOENT;
1125
1126        info = irq_get_handler_data(irq);
1127
1128        if (!info)
1129                return -ENOENT;
1130
1131        WARN_ON(info->refcnt != -1);
1132
1133        info->refcnt = 1;
1134
1135        return 0;
1136}
1137EXPORT_SYMBOL_GPL(evtchn_make_refcounted);
1138
1139int evtchn_get(unsigned int evtchn)
1140{
1141        int irq;
1142        struct irq_info *info;
1143        int err = -ENOENT;
1144
1145        if (evtchn >= NR_EVENT_CHANNELS)
1146                return -EINVAL;
1147
1148        mutex_lock(&irq_mapping_update_lock);
1149
1150        irq = evtchn_to_irq[evtchn];
1151        if (irq == -1)
1152                goto done;
1153
1154        info = irq_get_handler_data(irq);
1155
1156        if (!info)
1157                goto done;
1158
1159        err = -EINVAL;
1160        if (info->refcnt <= 0)
1161                goto done;
1162
1163        info->refcnt++;
1164        err = 0;
1165 done:
1166        mutex_unlock(&irq_mapping_update_lock);
1167
1168        return err;
1169}
1170EXPORT_SYMBOL_GPL(evtchn_get);
1171
1172void evtchn_put(unsigned int evtchn)
1173{
1174        int irq = evtchn_to_irq[evtchn];
1175        if (WARN_ON(irq == -1))
1176                return;
1177        unbind_from_irq(irq);
1178}
1179EXPORT_SYMBOL_GPL(evtchn_put);
1180
1181void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
1182{
1183        int irq = per_cpu(ipi_to_irq, cpu)[vector];
1184        BUG_ON(irq < 0);
1185        notify_remote_via_irq(irq);
1186}
1187
1188irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
1189{
1190        struct shared_info *sh = HYPERVISOR_shared_info;
1191        int cpu = smp_processor_id();
1192        unsigned long *cpu_evtchn = per_cpu(cpu_evtchn_mask, cpu);
1193        int i;
1194        unsigned long flags;
1195        static DEFINE_SPINLOCK(debug_lock);
1196        struct vcpu_info *v;
1197
1198        spin_lock_irqsave(&debug_lock, flags);
1199
1200        printk("\nvcpu %d\n  ", cpu);
1201
1202        for_each_online_cpu(i) {
1203                int pending;
1204                v = per_cpu(xen_vcpu, i);
1205                pending = (get_irq_regs() && i == cpu)
1206                        ? xen_irqs_disabled(get_irq_regs())
1207                        : v->evtchn_upcall_mask;
1208                printk("%d: masked=%d pending=%d event_sel %0*lx\n  ", i,
1209                       pending, v->evtchn_upcall_pending,
1210                       (int)(sizeof(v->evtchn_pending_sel)*2),
1211                       v->evtchn_pending_sel);
1212        }
1213        v = per_cpu(xen_vcpu, cpu);
1214
1215        printk("\npending:\n   ");
1216        for (i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--)
1217                printk("%0*lx%s", (int)sizeof(sh->evtchn_pending[0])*2,
1218                       sh->evtchn_pending[i],
1219                       i % 8 == 0 ? "\n   " : " ");
1220        printk("\nglobal mask:\n   ");
1221        for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
1222                printk("%0*lx%s",
1223                       (int)(sizeof(sh->evtchn_mask[0])*2),
1224                       sh->evtchn_mask[i],
1225                       i % 8 == 0 ? "\n   " : " ");
1226
1227        printk("\nglobally unmasked:\n   ");
1228        for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
1229                printk("%0*lx%s", (int)(sizeof(sh->evtchn_mask[0])*2),
1230                       sh->evtchn_pending[i] & ~sh->evtchn_mask[i],
1231                       i % 8 == 0 ? "\n   " : " ");
1232
1233        printk("\nlocal cpu%d mask:\n   ", cpu);
1234        for (i = (NR_EVENT_CHANNELS/BITS_PER_LONG)-1; i >= 0; i--)
1235                printk("%0*lx%s", (int)(sizeof(cpu_evtchn[0])*2),
1236                       cpu_evtchn[i],
1237                       i % 8 == 0 ? "\n   " : " ");
1238
1239        printk("\nlocally unmasked:\n   ");
1240        for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--) {
1241                unsigned long pending = sh->evtchn_pending[i]
1242                        & ~sh->evtchn_mask[i]
1243                        & cpu_evtchn[i];
1244                printk("%0*lx%s", (int)(sizeof(sh->evtchn_mask[0])*2),
1245                       pending, i % 8 == 0 ? "\n   " : " ");
1246        }
1247
1248        printk("\npending list:\n");
1249        for (i = 0; i < NR_EVENT_CHANNELS; i++) {
1250                if (sync_test_bit(i, sh->evtchn_pending)) {
1251                        int word_idx = i / BITS_PER_LONG;
1252                        printk("  %d: event %d -> irq %d%s%s%s\n",
1253                               cpu_from_evtchn(i), i,
1254                               evtchn_to_irq[i],
1255                               sync_test_bit(word_idx, &v->evtchn_pending_sel)
1256                                             ? "" : " l2-clear",
1257                               !sync_test_bit(i, sh->evtchn_mask)
1258                                             ? "" : " globally-masked",
1259                               sync_test_bit(i, cpu_evtchn)
1260                                             ? "" : " locally-masked");
1261                }
1262        }
1263
1264        spin_unlock_irqrestore(&debug_lock, flags);
1265
1266        return IRQ_HANDLED;
1267}
1268
1269static DEFINE_PER_CPU(unsigned, xed_nesting_count);
1270static DEFINE_PER_CPU(unsigned int, current_word_idx);
1271static DEFINE_PER_CPU(unsigned int, current_bit_idx);
1272
1273/*
1274 * Mask out the i least significant bits of w
1275 */
1276#define MASK_LSBS(w, i) (w & ((~0UL) << i))
1277
1278/*
1279 * Search the CPUs pending events bitmasks.  For each one found, map
1280 * the event number to an irq, and feed it into do_IRQ() for
1281 * handling.
1282 *
1283 * Xen uses a two-level bitmap to speed searching.  The first level is
1284 * a bitset of words which contain pending event bits.  The second
1285 * level is a bitset of pending events themselves.
1286 */
1287static void __xen_evtchn_do_upcall(void)
1288{
1289        int start_word_idx, start_bit_idx;
1290        int word_idx, bit_idx;
1291        int i;
1292        int cpu = get_cpu();
1293        struct shared_info *s = HYPERVISOR_shared_info;
1294        struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
1295        unsigned count;
1296
1297        do {
1298                unsigned long pending_words;
1299
1300                vcpu_info->evtchn_upcall_pending = 0;
1301
1302                if (__this_cpu_inc_return(xed_nesting_count) - 1)
1303                        goto out;
1304
1305#ifndef CONFIG_X86 /* No need for a barrier -- XCHG is a barrier on x86. */
1306                /* Clear master flag /before/ clearing selector flag. */
1307                wmb();
1308#endif
1309                pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
1310
1311                start_word_idx = __this_cpu_read(current_word_idx);
1312                start_bit_idx = __this_cpu_read(current_bit_idx);
1313
1314                word_idx = start_word_idx;
1315
1316                for (i = 0; pending_words != 0; i++) {
1317                        unsigned long pending_bits;
1318                        unsigned long words;
1319
1320                        words = MASK_LSBS(pending_words, word_idx);
1321
1322                        /*
1323                         * If we masked out all events, wrap to beginning.
1324                         */
1325                        if (words == 0) {
1326                                word_idx = 0;
1327                                bit_idx = 0;
1328                                continue;
1329                        }
1330                        word_idx = __ffs(words);
1331
1332                        pending_bits = active_evtchns(cpu, s, word_idx);
1333                        bit_idx = 0; /* usually scan entire word from start */
1334                        if (word_idx == start_word_idx) {
1335                                /* We scan the starting word in two parts */
1336                                if (i == 0)
1337                                        /* 1st time: start in the middle */
1338                                        bit_idx = start_bit_idx;
1339                                else
1340                                        /* 2nd time: mask bits done already */
1341                                        bit_idx &= (1UL << start_bit_idx) - 1;
1342                        }
1343
1344                        do {
1345                                unsigned long bits;
1346                                int port, irq;
1347                                struct irq_desc *desc;
1348
1349                                bits = MASK_LSBS(pending_bits, bit_idx);
1350
1351                                /* If we masked out all events, move on. */
1352                                if (bits == 0)
1353                                        break;
1354
1355                                bit_idx = __ffs(bits);
1356
1357                                /* Process port. */
1358                                port = (word_idx * BITS_PER_LONG) + bit_idx;
1359                                irq = evtchn_to_irq[port];
1360
1361                                if (irq != -1) {
1362                                        desc = irq_to_desc(irq);
1363                                        if (desc)
1364                                                generic_handle_irq_desc(irq, desc);
1365                                }
1366
1367                                bit_idx = (bit_idx + 1) % BITS_PER_LONG;
1368
1369                                /* Next caller starts at last processed + 1 */
1370                                __this_cpu_write(current_word_idx,
1371                                                 bit_idx ? word_idx :
1372                                                 (word_idx+1) % BITS_PER_LONG);
1373                                __this_cpu_write(current_bit_idx, bit_idx);
1374                        } while (bit_idx != 0);
1375
1376                        /* Scan start_l1i twice; all others once. */
1377                        if ((word_idx != start_word_idx) || (i != 0))
1378                                pending_words &= ~(1UL << word_idx);
1379
1380                        word_idx = (word_idx + 1) % BITS_PER_LONG;
1381                }
1382
1383                BUG_ON(!irqs_disabled());
1384
1385                count = __this_cpu_read(xed_nesting_count);
1386                __this_cpu_write(xed_nesting_count, 0);
1387        } while (count != 1 || vcpu_info->evtchn_upcall_pending);
1388
1389out:
1390
1391        put_cpu();
1392}
1393
1394void xen_evtchn_do_upcall(struct pt_regs *regs)
1395{
1396        struct pt_regs *old_regs = set_irq_regs(regs);
1397
1398        irq_enter();
1399#ifdef CONFIG_X86
1400        exit_idle();
1401#endif
1402
1403        __xen_evtchn_do_upcall();
1404
1405        irq_exit();
1406        set_irq_regs(old_regs);
1407}
1408
1409void xen_hvm_evtchn_do_upcall(void)
1410{
1411        __xen_evtchn_do_upcall();
1412}
1413EXPORT_SYMBOL_GPL(xen_hvm_evtchn_do_upcall);
1414
1415/* Rebind a new event channel to an existing irq. */
1416void rebind_evtchn_irq(int evtchn, int irq)
1417{
1418        struct irq_info *info = info_for_irq(irq);
1419
1420        /* Make sure the irq is masked, since the new event channel
1421           will also be masked. */
1422        disable_irq(irq);
1423
1424        mutex_lock(&irq_mapping_update_lock);
1425
1426        /* After resume the irq<->evtchn mappings are all cleared out */
1427        BUG_ON(evtchn_to_irq[evtchn] != -1);
1428        /* Expect irq to have been bound before,
1429           so there should be a proper type */
1430        BUG_ON(info->type == IRQT_UNBOUND);
1431
1432        xen_irq_info_evtchn_init(irq, evtchn);
1433
1434        mutex_unlock(&irq_mapping_update_lock);
1435
1436        /* new event channels are always bound to cpu 0 */
1437        irq_set_affinity(irq, cpumask_of(0));
1438
1439        /* Unmask the event channel. */
1440        enable_irq(irq);
1441}
1442
1443/* Rebind an evtchn so that it gets delivered to a specific cpu */
1444static int rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
1445{
1446        struct evtchn_bind_vcpu bind_vcpu;
1447        int evtchn = evtchn_from_irq(irq);
1448
1449        if (!VALID_EVTCHN(evtchn))
1450                return -1;
1451
1452        /*
1453         * Events delivered via platform PCI interrupts are always
1454         * routed to vcpu 0 and hence cannot be rebound.
1455         */
1456        if (xen_hvm_domain() && !xen_have_vector_callback)
1457                return -1;
1458
1459        /* Send future instances of this interrupt to other vcpu. */
1460        bind_vcpu.port = evtchn;
1461        bind_vcpu.vcpu = tcpu;
1462
1463        /*
1464         * If this fails, it usually just indicates that we're dealing with a
1465         * virq or IPI channel, which don't actually need to be rebound. Ignore
1466         * it, but don't do the xenlinux-level rebind in that case.
1467         */
1468        if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
1469                bind_evtchn_to_cpu(evtchn, tcpu);
1470
1471        return 0;
1472}
1473
1474static int set_affinity_irq(struct irq_data *data, const struct cpumask *dest,
1475                            bool force)
1476{
1477        unsigned tcpu = cpumask_first(dest);
1478
1479        return rebind_irq_to_cpu(data->irq, tcpu);
1480}
1481
1482int resend_irq_on_evtchn(unsigned int irq)
1483{
1484        int masked, evtchn = evtchn_from_irq(irq);
1485        struct shared_info *s = HYPERVISOR_shared_info;
1486
1487        if (!VALID_EVTCHN(evtchn))
1488                return 1;
1489
1490        masked = sync_test_and_set_bit(evtchn, s->evtchn_mask);
1491        sync_set_bit(evtchn, s->evtchn_pending);
1492        if (!masked)
1493                unmask_evtchn(evtchn);
1494
1495        return 1;
1496}
1497
1498static void enable_dynirq(struct irq_data *data)
1499{
1500        int evtchn = evtchn_from_irq(data->irq);
1501
1502        if (VALID_EVTCHN(evtchn))
1503                unmask_evtchn(evtchn);
1504}
1505
1506static void disable_dynirq(struct irq_data *data)
1507{
1508        int evtchn = evtchn_from_irq(data->irq);
1509
1510        if (VALID_EVTCHN(evtchn))
1511                mask_evtchn(evtchn);
1512}
1513
1514static void ack_dynirq(struct irq_data *data)
1515{
1516        int evtchn = evtchn_from_irq(data->irq);
1517
1518        irq_move_irq(data);
1519
1520        if (VALID_EVTCHN(evtchn))
1521                clear_evtchn(evtchn);
1522}
1523
1524static void mask_ack_dynirq(struct irq_data *data)
1525{
1526        disable_dynirq(data);
1527        ack_dynirq(data);
1528}
1529
1530static int retrigger_dynirq(struct irq_data *data)
1531{
1532        int evtchn = evtchn_from_irq(data->irq);
1533        struct shared_info *sh = HYPERVISOR_shared_info;
1534        int ret = 0;
1535
1536        if (VALID_EVTCHN(evtchn)) {
1537                int masked;
1538
1539                masked = sync_test_and_set_bit(evtchn, sh->evtchn_mask);
1540                sync_set_bit(evtchn, sh->evtchn_pending);
1541                if (!masked)
1542                        unmask_evtchn(evtchn);
1543                ret = 1;
1544        }
1545
1546        return ret;
1547}
1548
1549static void restore_pirqs(void)
1550{
1551        int pirq, rc, irq, gsi;
1552        struct physdev_map_pirq map_irq;
1553        struct irq_info *info;
1554
1555        list_for_each_entry(info, &xen_irq_list_head, list) {
1556                if (info->type != IRQT_PIRQ)
1557                        continue;
1558
1559                pirq = info->u.pirq.pirq;
1560                gsi = info->u.pirq.gsi;
1561                irq = info->irq;
1562
1563                /* save/restore of PT devices doesn't work, so at this point the
1564                 * only devices present are GSI based emulated devices */
1565                if (!gsi)
1566                        continue;
1567
1568                map_irq.domid = DOMID_SELF;
1569                map_irq.type = MAP_PIRQ_TYPE_GSI;
1570                map_irq.index = gsi;
1571                map_irq.pirq = pirq;
1572
1573                rc = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq, &map_irq);
1574                if (rc) {
1575                        printk(KERN_WARNING "xen map irq failed gsi=%d irq=%d pirq=%d rc=%d\n",
1576                                        gsi, irq, pirq, rc);
1577                        xen_free_irq(irq);
1578                        continue;
1579                }
1580
1581                printk(KERN_DEBUG "xen: --> irq=%d, pirq=%d\n", irq, map_irq.pirq);
1582
1583                __startup_pirq(irq);
1584        }
1585}
1586
1587static void restore_cpu_virqs(unsigned int cpu)
1588{
1589        struct evtchn_bind_virq bind_virq;
1590        int virq, irq, evtchn;
1591
1592        for (virq = 0; virq < NR_VIRQS; virq++) {
1593                if ((irq = per_cpu(virq_to_irq, cpu)[virq]) == -1)
1594                        continue;
1595
1596                BUG_ON(virq_from_irq(irq) != virq);
1597
1598                /* Get a new binding from Xen. */
1599                bind_virq.virq = virq;
1600                bind_virq.vcpu = cpu;
1601                if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
1602                                                &bind_virq) != 0)
1603                        BUG();
1604                evtchn = bind_virq.port;
1605
1606                /* Record the new mapping. */
1607                xen_irq_info_virq_init(cpu, irq, evtchn, virq);
1608                bind_evtchn_to_cpu(evtchn, cpu);
1609        }
1610}
1611
1612static void restore_cpu_ipis(unsigned int cpu)
1613{
1614        struct evtchn_bind_ipi bind_ipi;
1615        int ipi, irq, evtchn;
1616
1617        for (ipi = 0; ipi < XEN_NR_IPIS; ipi++) {
1618                if ((irq = per_cpu(ipi_to_irq, cpu)[ipi]) == -1)
1619                        continue;
1620
1621                BUG_ON(ipi_from_irq(irq) != ipi);
1622
1623                /* Get a new binding from Xen. */
1624                bind_ipi.vcpu = cpu;
1625                if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
1626                                                &bind_ipi) != 0)
1627                        BUG();
1628                evtchn = bind_ipi.port;
1629
1630                /* Record the new mapping. */
1631                xen_irq_info_ipi_init(cpu, irq, evtchn, ipi);
1632                bind_evtchn_to_cpu(evtchn, cpu);
1633        }
1634}
1635
1636/* Clear an irq's pending state, in preparation for polling on it */
1637void xen_clear_irq_pending(int irq)
1638{
1639        int evtchn = evtchn_from_irq(irq);
1640
1641        if (VALID_EVTCHN(evtchn))
1642                clear_evtchn(evtchn);
1643}
1644EXPORT_SYMBOL(xen_clear_irq_pending);
1645void xen_set_irq_pending(int irq)
1646{
1647        int evtchn = evtchn_from_irq(irq);
1648
1649        if (VALID_EVTCHN(evtchn))
1650                set_evtchn(evtchn);
1651}
1652
1653bool xen_test_irq_pending(int irq)
1654{
1655        int evtchn = evtchn_from_irq(irq);
1656        bool ret = false;
1657
1658        if (VALID_EVTCHN(evtchn))
1659                ret = test_evtchn(evtchn);
1660
1661        return ret;
1662}
1663
1664/* Poll waiting for an irq to become pending with timeout.  In the usual case,
1665 * the irq will be disabled so it won't deliver an interrupt. */
1666void xen_poll_irq_timeout(int irq, u64 timeout)
1667{
1668        evtchn_port_t evtchn = evtchn_from_irq(irq);
1669
1670        if (VALID_EVTCHN(evtchn)) {
1671                struct sched_poll poll;
1672
1673                poll.nr_ports = 1;
1674                poll.timeout = timeout;
1675                set_xen_guest_handle(poll.ports, &evtchn);
1676
1677                if (HYPERVISOR_sched_op(SCHEDOP_poll, &poll) != 0)
1678                        BUG();
1679        }
1680}
1681EXPORT_SYMBOL(xen_poll_irq_timeout);
1682/* Poll waiting for an irq to become pending.  In the usual case, the
1683 * irq will be disabled so it won't deliver an interrupt. */
1684void xen_poll_irq(int irq)
1685{
1686        xen_poll_irq_timeout(irq, 0 /* no timeout */);
1687}
1688
1689/* Check whether the IRQ line is shared with other guests. */
1690int xen_test_irq_shared(int irq)
1691{
1692        struct irq_info *info = info_for_irq(irq);
1693        struct physdev_irq_status_query irq_status = { .irq = info->u.pirq.pirq };
1694
1695        if (HYPERVISOR_physdev_op(PHYSDEVOP_irq_status_query, &irq_status))
1696                return 0;
1697        return !(irq_status.flags & XENIRQSTAT_shared);
1698}
1699EXPORT_SYMBOL_GPL(xen_test_irq_shared);
1700
1701void xen_irq_resume(void)
1702{
1703        unsigned int cpu, evtchn;
1704        struct irq_info *info;
1705
1706        init_evtchn_cpu_bindings();
1707
1708        /* New event-channel space is not 'live' yet. */
1709        for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
1710                mask_evtchn(evtchn);
1711
1712        /* No IRQ <-> event-channel mappings. */
1713        list_for_each_entry(info, &xen_irq_list_head, list)
1714                info->evtchn = 0; /* zap event-channel binding */
1715
1716        for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
1717                evtchn_to_irq[evtchn] = -1;
1718
1719        for_each_possible_cpu(cpu) {
1720                restore_cpu_virqs(cpu);
1721                restore_cpu_ipis(cpu);
1722        }
1723
1724        restore_pirqs();
1725}
1726
1727static struct irq_chip xen_dynamic_chip __read_mostly = {
1728        .name                   = "xen-dyn",
1729
1730        .irq_disable            = disable_dynirq,
1731        .irq_mask               = disable_dynirq,
1732        .irq_unmask             = enable_dynirq,
1733
1734        .irq_ack                = ack_dynirq,
1735        .irq_mask_ack           = mask_ack_dynirq,
1736
1737        .irq_set_affinity       = set_affinity_irq,
1738        .irq_retrigger          = retrigger_dynirq,
1739};
1740
1741static struct irq_chip xen_pirq_chip __read_mostly = {
1742        .name                   = "xen-pirq",
1743
1744        .irq_startup            = startup_pirq,
1745        .irq_shutdown           = shutdown_pirq,
1746        .irq_enable             = enable_pirq,
1747        .irq_disable            = disable_pirq,
1748
1749        .irq_mask               = disable_dynirq,
1750        .irq_unmask             = enable_dynirq,
1751
1752        .irq_ack                = eoi_pirq,
1753        .irq_eoi                = eoi_pirq,
1754        .irq_mask_ack           = mask_ack_pirq,
1755
1756        .irq_set_affinity       = set_affinity_irq,
1757
1758        .irq_retrigger          = retrigger_dynirq,
1759};
1760
1761static struct irq_chip xen_percpu_chip __read_mostly = {
1762        .name                   = "xen-percpu",
1763
1764        .irq_disable            = disable_dynirq,
1765        .irq_mask               = disable_dynirq,
1766        .irq_unmask             = enable_dynirq,
1767
1768        .irq_ack                = ack_dynirq,
1769};
1770
1771int xen_set_callback_via(uint64_t via)
1772{
1773        struct xen_hvm_param a;
1774        a.domid = DOMID_SELF;
1775        a.index = HVM_PARAM_CALLBACK_IRQ;
1776        a.value = via;
1777        return HYPERVISOR_hvm_op(HVMOP_set_param, &a);
1778}
1779EXPORT_SYMBOL_GPL(xen_set_callback_via);
1780
1781#ifdef CONFIG_XEN_PVHVM
1782/* Vector callbacks are better than PCI interrupts to receive event
1783 * channel notifications because we can receive vector callbacks on any
1784 * vcpu and we don't need PCI support or APIC interactions. */
1785void xen_callback_vector(void)
1786{
1787        int rc;
1788        uint64_t callback_via;
1789        if (xen_have_vector_callback) {
1790                callback_via = HVM_CALLBACK_VECTOR(XEN_HVM_EVTCHN_CALLBACK);
1791                rc = xen_set_callback_via(callback_via);
1792                if (rc) {
1793                        printk(KERN_ERR "Request for Xen HVM callback vector"
1794                                        " failed.\n");
1795                        xen_have_vector_callback = 0;
1796                        return;
1797                }
1798                printk(KERN_INFO "Xen HVM callback vector for event delivery is "
1799                                "enabled\n");
1800                /* in the restore case the vector has already been allocated */
1801                if (!test_bit(XEN_HVM_EVTCHN_CALLBACK, used_vectors))
1802                        alloc_intr_gate(XEN_HVM_EVTCHN_CALLBACK, xen_hvm_callback_vector);
1803        }
1804}
1805#else
1806void xen_callback_vector(void) {}
1807#endif
1808
1809void __init xen_init_IRQ(void)
1810{
1811        int i;
1812
1813        evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
1814                                    GFP_KERNEL);
1815        BUG_ON(!evtchn_to_irq);
1816        for (i = 0; i < NR_EVENT_CHANNELS; i++)
1817                evtchn_to_irq[i] = -1;
1818
1819        init_evtchn_cpu_bindings();
1820
1821        /* No event channels are 'live' right now. */
1822        for (i = 0; i < NR_EVENT_CHANNELS; i++)
1823                mask_evtchn(i);
1824
1825        pirq_needs_eoi = pirq_needs_eoi_flag;
1826
1827#ifdef CONFIG_X86
1828        if (xen_hvm_domain()) {
1829                xen_callback_vector();
1830                native_init_IRQ();
1831                /* pci_xen_hvm_init must be called after native_init_IRQ so that
1832                 * __acpi_register_gsi can point at the right function */
1833                pci_xen_hvm_init();
1834        } else {
1835                int rc;
1836                struct physdev_pirq_eoi_gmfn eoi_gmfn;
1837
1838                irq_ctx_init(smp_processor_id());
1839                if (xen_initial_domain())
1840                        pci_xen_initial_domain();
1841
1842                pirq_eoi_map = (void *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
1843                eoi_gmfn.gmfn = virt_to_mfn(pirq_eoi_map);
1844                rc = HYPERVISOR_physdev_op(PHYSDEVOP_pirq_eoi_gmfn_v2, &eoi_gmfn);
1845                if (rc != 0) {
1846                        free_page((unsigned long) pirq_eoi_map);
1847                        pirq_eoi_map = NULL;
1848                } else
1849                        pirq_needs_eoi = pirq_check_eoi_map;
1850        }
1851#endif
1852}
1853
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