linux/virt/kvm/irq_comm.c
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   1/*
   2 * irq_comm.c: Common API for in kernel interrupt controller
   3 * Copyright (c) 2007, Intel Corporation.
   4 *
   5 * This program is free software; you can redistribute it and/or modify it
   6 * under the terms and conditions of the GNU General Public License,
   7 * version 2, as published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope it will be useful, but WITHOUT
  10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12 * more details.
  13 *
  14 * You should have received a copy of the GNU General Public License along with
  15 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  16 * Place - Suite 330, Boston, MA 02111-1307 USA.
  17 * Authors:
  18 *   Yaozu (Eddie) Dong <Eddie.dong@intel.com>
  19 *
  20 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
  21 */
  22
  23#include <linux/kvm_host.h>
  24#include <linux/slab.h>
  25#include <trace/events/kvm.h>
  26
  27#include <asm/msidef.h>
  28#ifdef CONFIG_IA64
  29#include <asm/iosapic.h>
  30#endif
  31
  32#include "irq.h"
  33
  34#include "ioapic.h"
  35
  36static inline int kvm_irq_line_state(unsigned long *irq_state,
  37                                     int irq_source_id, int level)
  38{
  39        /* Logical OR for level trig interrupt */
  40        if (level)
  41                set_bit(irq_source_id, irq_state);
  42        else
  43                clear_bit(irq_source_id, irq_state);
  44
  45        return !!(*irq_state);
  46}
  47
  48static int kvm_set_pic_irq(struct kvm_kernel_irq_routing_entry *e,
  49                           struct kvm *kvm, int irq_source_id, int level)
  50{
  51#ifdef CONFIG_X86
  52        struct kvm_pic *pic = pic_irqchip(kvm);
  53        level = kvm_irq_line_state(&pic->irq_states[e->irqchip.pin],
  54                                   irq_source_id, level);
  55        return kvm_pic_set_irq(pic, e->irqchip.pin, level);
  56#else
  57        return -1;
  58#endif
  59}
  60
  61static int kvm_set_ioapic_irq(struct kvm_kernel_irq_routing_entry *e,
  62                              struct kvm *kvm, int irq_source_id, int level)
  63{
  64        struct kvm_ioapic *ioapic = kvm->arch.vioapic;
  65        level = kvm_irq_line_state(&ioapic->irq_states[e->irqchip.pin],
  66                                   irq_source_id, level);
  67
  68        return kvm_ioapic_set_irq(ioapic, e->irqchip.pin, level);
  69}
  70
  71inline static bool kvm_is_dm_lowest_prio(struct kvm_lapic_irq *irq)
  72{
  73#ifdef CONFIG_IA64
  74        return irq->delivery_mode ==
  75                (IOSAPIC_LOWEST_PRIORITY << IOSAPIC_DELIVERY_SHIFT);
  76#else
  77        return irq->delivery_mode == APIC_DM_LOWEST;
  78#endif
  79}
  80
  81int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
  82                struct kvm_lapic_irq *irq)
  83{
  84        int i, r = -1;
  85        struct kvm_vcpu *vcpu, *lowest = NULL;
  86
  87        if (irq->dest_mode == 0 && irq->dest_id == 0xff &&
  88                        kvm_is_dm_lowest_prio(irq))
  89                printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n");
  90
  91        kvm_for_each_vcpu(i, vcpu, kvm) {
  92                if (!kvm_apic_present(vcpu))
  93                        continue;
  94
  95                if (!kvm_apic_match_dest(vcpu, src, irq->shorthand,
  96                                        irq->dest_id, irq->dest_mode))
  97                        continue;
  98
  99                if (!kvm_is_dm_lowest_prio(irq)) {
 100                        if (r < 0)
 101                                r = 0;
 102                        r += kvm_apic_set_irq(vcpu, irq);
 103                } else if (kvm_lapic_enabled(vcpu)) {
 104                        if (!lowest)
 105                                lowest = vcpu;
 106                        else if (kvm_apic_compare_prio(vcpu, lowest) < 0)
 107                                lowest = vcpu;
 108                }
 109        }
 110
 111        if (lowest)
 112                r = kvm_apic_set_irq(lowest, irq);
 113
 114        return r;
 115}
 116
 117int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
 118                struct kvm *kvm, int irq_source_id, int level)
 119{
 120        struct kvm_lapic_irq irq;
 121
 122        if (!level)
 123                return -1;
 124
 125        trace_kvm_msi_set_irq(e->msi.address_lo, e->msi.data);
 126
 127        irq.dest_id = (e->msi.address_lo &
 128                        MSI_ADDR_DEST_ID_MASK) >> MSI_ADDR_DEST_ID_SHIFT;
 129        irq.vector = (e->msi.data &
 130                        MSI_DATA_VECTOR_MASK) >> MSI_DATA_VECTOR_SHIFT;
 131        irq.dest_mode = (1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo;
 132        irq.trig_mode = (1 << MSI_DATA_TRIGGER_SHIFT) & e->msi.data;
 133        irq.delivery_mode = e->msi.data & 0x700;
 134        irq.level = 1;
 135        irq.shorthand = 0;
 136
 137        /* TODO Deal with RH bit of MSI message address */
 138        return kvm_irq_delivery_to_apic(kvm, NULL, &irq);
 139}
 140
 141/*
 142 * Return value:
 143 *  < 0   Interrupt was ignored (masked or not delivered for other reasons)
 144 *  = 0   Interrupt was coalesced (previous irq is still pending)
 145 *  > 0   Number of CPUs interrupt was delivered to
 146 */
 147int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level)
 148{
 149        struct kvm_kernel_irq_routing_entry *e, irq_set[KVM_NR_IRQCHIPS];
 150        int ret = -1, i = 0;
 151        struct kvm_irq_routing_table *irq_rt;
 152        struct hlist_node *n;
 153
 154        trace_kvm_set_irq(irq, level, irq_source_id);
 155
 156        /* Not possible to detect if the guest uses the PIC or the
 157         * IOAPIC.  So set the bit in both. The guest will ignore
 158         * writes to the unused one.
 159         */
 160        rcu_read_lock();
 161        irq_rt = rcu_dereference(kvm->irq_routing);
 162        if (irq < irq_rt->nr_rt_entries)
 163                hlist_for_each_entry(e, n, &irq_rt->map[irq], link)
 164                        irq_set[i++] = *e;
 165        rcu_read_unlock();
 166
 167        while(i--) {
 168                int r;
 169                r = irq_set[i].set(&irq_set[i], kvm, irq_source_id, level);
 170                if (r < 0)
 171                        continue;
 172
 173                ret = r + ((ret < 0) ? 0 : ret);
 174        }
 175
 176        return ret;
 177}
 178
 179void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
 180{
 181        struct kvm_irq_ack_notifier *kian;
 182        struct hlist_node *n;
 183        int gsi;
 184
 185        trace_kvm_ack_irq(irqchip, pin);
 186
 187        rcu_read_lock();
 188        gsi = rcu_dereference(kvm->irq_routing)->chip[irqchip][pin];
 189        if (gsi != -1)
 190                hlist_for_each_entry_rcu(kian, n, &kvm->irq_ack_notifier_list,
 191                                         link)
 192                        if (kian->gsi == gsi)
 193                                kian->irq_acked(kian);
 194        rcu_read_unlock();
 195}
 196
 197void kvm_register_irq_ack_notifier(struct kvm *kvm,
 198                                   struct kvm_irq_ack_notifier *kian)
 199{
 200        mutex_lock(&kvm->irq_lock);
 201        hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list);
 202        mutex_unlock(&kvm->irq_lock);
 203}
 204
 205void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
 206                                    struct kvm_irq_ack_notifier *kian)
 207{
 208        mutex_lock(&kvm->irq_lock);
 209        hlist_del_init_rcu(&kian->link);
 210        mutex_unlock(&kvm->irq_lock);
 211        synchronize_rcu();
 212}
 213
 214int kvm_request_irq_source_id(struct kvm *kvm)
 215{
 216        unsigned long *bitmap = &kvm->arch.irq_sources_bitmap;
 217        int irq_source_id;
 218
 219        mutex_lock(&kvm->irq_lock);
 220        irq_source_id = find_first_zero_bit(bitmap, BITS_PER_LONG);
 221
 222        if (irq_source_id >= BITS_PER_LONG) {
 223                printk(KERN_WARNING "kvm: exhaust allocatable IRQ sources!\n");
 224                irq_source_id = -EFAULT;
 225                goto unlock;
 226        }
 227
 228        ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
 229        set_bit(irq_source_id, bitmap);
 230unlock:
 231        mutex_unlock(&kvm->irq_lock);
 232
 233        return irq_source_id;
 234}
 235
 236void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id)
 237{
 238        int i;
 239
 240        ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
 241
 242        mutex_lock(&kvm->irq_lock);
 243        if (irq_source_id < 0 ||
 244            irq_source_id >= BITS_PER_LONG) {
 245                printk(KERN_ERR "kvm: IRQ source ID out of range!\n");
 246                goto unlock;
 247        }
 248        clear_bit(irq_source_id, &kvm->arch.irq_sources_bitmap);
 249        if (!irqchip_in_kernel(kvm))
 250                goto unlock;
 251
 252        for (i = 0; i < KVM_IOAPIC_NUM_PINS; i++) {
 253                clear_bit(irq_source_id, &kvm->arch.vioapic->irq_states[i]);
 254                if (i >= 16)
 255                        continue;
 256#ifdef CONFIG_X86
 257                clear_bit(irq_source_id, &pic_irqchip(kvm)->irq_states[i]);
 258#endif
 259        }
 260unlock:
 261        mutex_unlock(&kvm->irq_lock);
 262}
 263
 264void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq,
 265                                    struct kvm_irq_mask_notifier *kimn)
 266{
 267        mutex_lock(&kvm->irq_lock);
 268        kimn->irq = irq;
 269        hlist_add_head_rcu(&kimn->link, &kvm->mask_notifier_list);
 270        mutex_unlock(&kvm->irq_lock);
 271}
 272
 273void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq,
 274                                      struct kvm_irq_mask_notifier *kimn)
 275{
 276        mutex_lock(&kvm->irq_lock);
 277        hlist_del_rcu(&kimn->link);
 278        mutex_unlock(&kvm->irq_lock);
 279        synchronize_rcu();
 280}
 281
 282void kvm_fire_mask_notifiers(struct kvm *kvm, unsigned irqchip, unsigned pin,
 283                             bool mask)
 284{
 285        struct kvm_irq_mask_notifier *kimn;
 286        struct hlist_node *n;
 287        int gsi;
 288
 289        rcu_read_lock();
 290        gsi = rcu_dereference(kvm->irq_routing)->chip[irqchip][pin];
 291        if (gsi != -1)
 292                hlist_for_each_entry_rcu(kimn, n, &kvm->mask_notifier_list, link)
 293                        if (kimn->irq == gsi)
 294                                kimn->func(kimn, mask);
 295        rcu_read_unlock();
 296}
 297
 298void kvm_free_irq_routing(struct kvm *kvm)
 299{
 300        /* Called only during vm destruction. Nobody can use the pointer
 301           at this stage */
 302        kfree(kvm->irq_routing);
 303}
 304
 305static int setup_routing_entry(struct kvm_irq_routing_table *rt,
 306                               struct kvm_kernel_irq_routing_entry *e,
 307                               const struct kvm_irq_routing_entry *ue)
 308{
 309        int r = -EINVAL;
 310        int delta;
 311        unsigned max_pin;
 312        struct kvm_kernel_irq_routing_entry *ei;
 313        struct hlist_node *n;
 314
 315        /*
 316         * Do not allow GSI to be mapped to the same irqchip more than once.
 317         * Allow only one to one mapping between GSI and MSI.
 318         */
 319        hlist_for_each_entry(ei, n, &rt->map[ue->gsi], link)
 320                if (ei->type == KVM_IRQ_ROUTING_MSI ||
 321                    ue->u.irqchip.irqchip == ei->irqchip.irqchip)
 322                        return r;
 323
 324        e->gsi = ue->gsi;
 325        e->type = ue->type;
 326        switch (ue->type) {
 327        case KVM_IRQ_ROUTING_IRQCHIP:
 328                delta = 0;
 329                switch (ue->u.irqchip.irqchip) {
 330                case KVM_IRQCHIP_PIC_MASTER:
 331                        e->set = kvm_set_pic_irq;
 332                        max_pin = 16;
 333                        break;
 334                case KVM_IRQCHIP_PIC_SLAVE:
 335                        e->set = kvm_set_pic_irq;
 336                        max_pin = 16;
 337                        delta = 8;
 338                        break;
 339                case KVM_IRQCHIP_IOAPIC:
 340                        max_pin = KVM_IOAPIC_NUM_PINS;
 341                        e->set = kvm_set_ioapic_irq;
 342                        break;
 343                default:
 344                        goto out;
 345                }
 346                e->irqchip.irqchip = ue->u.irqchip.irqchip;
 347                e->irqchip.pin = ue->u.irqchip.pin + delta;
 348                if (e->irqchip.pin >= max_pin)
 349                        goto out;
 350                rt->chip[ue->u.irqchip.irqchip][e->irqchip.pin] = ue->gsi;
 351                break;
 352        case KVM_IRQ_ROUTING_MSI:
 353                e->set = kvm_set_msi;
 354                e->msi.address_lo = ue->u.msi.address_lo;
 355                e->msi.address_hi = ue->u.msi.address_hi;
 356                e->msi.data = ue->u.msi.data;
 357                break;
 358        default:
 359                goto out;
 360        }
 361
 362        hlist_add_head(&e->link, &rt->map[e->gsi]);
 363        r = 0;
 364out:
 365        return r;
 366}
 367
 368
 369int kvm_set_irq_routing(struct kvm *kvm,
 370                        const struct kvm_irq_routing_entry *ue,
 371                        unsigned nr,
 372                        unsigned flags)
 373{
 374        struct kvm_irq_routing_table *new, *old;
 375        u32 i, j, nr_rt_entries = 0;
 376        int r;
 377
 378        for (i = 0; i < nr; ++i) {
 379                if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
 380                        return -EINVAL;
 381                nr_rt_entries = max(nr_rt_entries, ue[i].gsi);
 382        }
 383
 384        nr_rt_entries += 1;
 385
 386        new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head))
 387                      + (nr * sizeof(struct kvm_kernel_irq_routing_entry)),
 388                      GFP_KERNEL);
 389
 390        if (!new)
 391                return -ENOMEM;
 392
 393        new->rt_entries = (void *)&new->map[nr_rt_entries];
 394
 395        new->nr_rt_entries = nr_rt_entries;
 396        for (i = 0; i < 3; i++)
 397                for (j = 0; j < KVM_IOAPIC_NUM_PINS; j++)
 398                        new->chip[i][j] = -1;
 399
 400        for (i = 0; i < nr; ++i) {
 401                r = -EINVAL;
 402                if (ue->flags)
 403                        goto out;
 404                r = setup_routing_entry(new, &new->rt_entries[i], ue);
 405                if (r)
 406                        goto out;
 407                ++ue;
 408        }
 409
 410        mutex_lock(&kvm->irq_lock);
 411        old = kvm->irq_routing;
 412        kvm_irq_routing_update(kvm, new);
 413        mutex_unlock(&kvm->irq_lock);
 414
 415        synchronize_rcu();
 416
 417        new = old;
 418        r = 0;
 419
 420out:
 421        kfree(new);
 422        return r;
 423}
 424
 425#define IOAPIC_ROUTING_ENTRY(irq) \
 426        { .gsi = irq, .type = KVM_IRQ_ROUTING_IRQCHIP,  \
 427          .u.irqchip.irqchip = KVM_IRQCHIP_IOAPIC, .u.irqchip.pin = (irq) }
 428#define ROUTING_ENTRY1(irq) IOAPIC_ROUTING_ENTRY(irq)
 429
 430#ifdef CONFIG_X86
 431#  define PIC_ROUTING_ENTRY(irq) \
 432        { .gsi = irq, .type = KVM_IRQ_ROUTING_IRQCHIP,  \
 433          .u.irqchip.irqchip = SELECT_PIC(irq), .u.irqchip.pin = (irq) % 8 }
 434#  define ROUTING_ENTRY2(irq) \
 435        IOAPIC_ROUTING_ENTRY(irq), PIC_ROUTING_ENTRY(irq)
 436#else
 437#  define ROUTING_ENTRY2(irq) \
 438        IOAPIC_ROUTING_ENTRY(irq)
 439#endif
 440
 441static const struct kvm_irq_routing_entry default_routing[] = {
 442        ROUTING_ENTRY2(0), ROUTING_ENTRY2(1),
 443        ROUTING_ENTRY2(2), ROUTING_ENTRY2(3),
 444        ROUTING_ENTRY2(4), ROUTING_ENTRY2(5),
 445        ROUTING_ENTRY2(6), ROUTING_ENTRY2(7),
 446        ROUTING_ENTRY2(8), ROUTING_ENTRY2(9),
 447        ROUTING_ENTRY2(10), ROUTING_ENTRY2(11),
 448        ROUTING_ENTRY2(12), ROUTING_ENTRY2(13),
 449        ROUTING_ENTRY2(14), ROUTING_ENTRY2(15),
 450        ROUTING_ENTRY1(16), ROUTING_ENTRY1(17),
 451        ROUTING_ENTRY1(18), ROUTING_ENTRY1(19),
 452        ROUTING_ENTRY1(20), ROUTING_ENTRY1(21),
 453        ROUTING_ENTRY1(22), ROUTING_ENTRY1(23),
 454#ifdef CONFIG_IA64
 455        ROUTING_ENTRY1(24), ROUTING_ENTRY1(25),
 456        ROUTING_ENTRY1(26), ROUTING_ENTRY1(27),
 457        ROUTING_ENTRY1(28), ROUTING_ENTRY1(29),
 458        ROUTING_ENTRY1(30), ROUTING_ENTRY1(31),
 459        ROUTING_ENTRY1(32), ROUTING_ENTRY1(33),
 460        ROUTING_ENTRY1(34), ROUTING_ENTRY1(35),
 461        ROUTING_ENTRY1(36), ROUTING_ENTRY1(37),
 462        ROUTING_ENTRY1(38), ROUTING_ENTRY1(39),
 463        ROUTING_ENTRY1(40), ROUTING_ENTRY1(41),
 464        ROUTING_ENTRY1(42), ROUTING_ENTRY1(43),
 465        ROUTING_ENTRY1(44), ROUTING_ENTRY1(45),
 466        ROUTING_ENTRY1(46), ROUTING_ENTRY1(47),
 467#endif
 468};
 469
 470int kvm_setup_default_irq_routing(struct kvm *kvm)
 471{
 472        return kvm_set_irq_routing(kvm, default_routing,
 473                                   ARRAY_SIZE(default_routing), 0);
 474}
 475