virt/kvm/irq_comm.c

   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
  36 static int kvm_set_pic_irq(struct kvm_kernel_irq_routing_entry *e,
  37                            struct kvm *kvm, int irq_source_id, int level)
  38 {
  39 #ifdef CONFIG_X86
  40         struct kvm_pic *pic = pic_irqchip(kvm);
  41         return kvm_pic_set_irq(pic, e->irqchip.pin, irq_source_id, level);
  42 #else
  43         return -1;
  44 #endif
  45 }
  46
  47 static int kvm_set_ioapic_irq(struct kvm_kernel_irq_routing_entry *e,
  48                               struct kvm *kvm, int irq_source_id, int level)
  49 {
  50         struct kvm_ioapic *ioapic = kvm->arch.vioapic;
  51         return kvm_ioapic_set_irq(ioapic, e->irqchip.pin, irq_source_id, level);
  52 }
  53
  54 inline static bool kvm_is_dm_lowest_prio(struct kvm_lapic_irq *irq)
  55 {
  56 #ifdef CONFIG_IA64
  57         return irq->delivery_mode ==
  58                 (IOSAPIC_LOWEST_PRIORITY << IOSAPIC_DELIVERY_SHIFT);
  59 #else
  60         return irq->delivery_mode == APIC_DM_LOWEST;
  61 #endif
  62 }
  63
  64 int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
  65                 struct kvm_lapic_irq *irq)
  66 {
  67         int i, r = -1;
  68         struct kvm_vcpu *vcpu, *lowest = NULL;
  69
  70         if (irq->dest_mode == 0 && irq->dest_id == 0xff &&
  71                         kvm_is_dm_lowest_prio(irq)) {
  72                 printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n");
  73                 irq->delivery_mode = APIC_DM_FIXED;
  74         }
  75
  76         if (kvm_irq_delivery_to_apic_fast(kvm, src, irq, &r))
  77                 return r;
  78
  79         kvm_for_each_vcpu(i, vcpu, kvm) {
  80                 if (!kvm_apic_present(vcpu))
  81                         continue;
  82
  83                 if (!kvm_apic_match_dest(vcpu, src, irq->shorthand,
  84                                         irq->dest_id, irq->dest_mode))
  85                         continue;
  86
  87                 if (!kvm_is_dm_lowest_prio(irq)) {
  88                         if (r < 0)
  89                                 r = 0;
  90                         r += kvm_apic_set_irq(vcpu, irq);
  91                 } else if (kvm_lapic_enabled(vcpu)) {
  92                         if (!lowest)
  93                                 lowest = vcpu;
  94                         else if (kvm_apic_compare_prio(vcpu, lowest) < 0)
  95                                 lowest = vcpu;
  96                 }
  97         }
  98
  99         if (lowest)
 100                 r = kvm_apic_set_irq(lowest, irq);
 101
 102         return r;
 103 }
 104
 105 static inline void kvm_set_msi_irq(struct kvm_kernel_irq_routing_entry *e,
 106                                    struct kvm_lapic_irq *irq)
 107 {
 108         trace_kvm_msi_set_irq(e->msi.address_lo, e->msi.data);
 109
 110         irq->dest_id = (e->msi.address_lo &
 111                         MSI_ADDR_DEST_ID_MASK) >> MSI_ADDR_DEST_ID_SHIFT;
 112         irq->vector = (e->msi.data &
 113                         MSI_DATA_VECTOR_MASK) >> MSI_DATA_VECTOR_SHIFT;
 114         irq->dest_mode = (1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo;
 115         irq->trig_mode = (1 << MSI_DATA_TRIGGER_SHIFT) & e->msi.data;
 116         irq->delivery_mode = e->msi.data & 0x700;
 117         irq->level = 1;
 118         irq->shorthand = 0;
 119         /* TODO Deal with RH bit of MSI message address */
 120 }
 121
 122 int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
 123                 struct kvm *kvm, int irq_source_id, int level)
 124 {
 125         struct kvm_lapic_irq irq;
 126
 127         if (!level)
 128                 return -1;
 129
 130         kvm_set_msi_irq(e, &irq);
 131
 132         return kvm_irq_delivery_to_apic(kvm, NULL, &irq);
 133 }
 134
 135
 136 static int kvm_set_msi_inatomic(struct kvm_kernel_irq_routing_entry *e,
 137                          struct kvm *kvm)
 138 {
 139         struct kvm_lapic_irq irq;
 140         int r;
 141
 142         kvm_set_msi_irq(e, &irq);
 143
 144         if (kvm_irq_delivery_to_apic_fast(kvm, NULL, &irq, &r))
 145                 return r;
 146         else
 147                 return -EWOULDBLOCK;
 148 }
 149
 150 int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
 151 {
 152         struct kvm_kernel_irq_routing_entry route;
 153
 154         if (!irqchip_in_kernel(kvm) || msi->flags != 0)
 155                 return -EINVAL;
 156
 157         route.msi.address_lo = msi->address_lo;
 158         route.msi.address_hi = msi->address_hi;
 159         route.msi.data = msi->data;
 160
 161         return kvm_set_msi(&route, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1);
 162 }
 163
 164 /*
 165  * Return value:
 166  *  < 0   Interrupt was ignored (masked or not delivered for other reasons)
 167  *  = 0   Interrupt was coalesced (previous irq is still pending)
 168  *  > 0   Number of CPUs interrupt was delivered to
 169  */
 170 int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level)
 171 {
 172         struct kvm_kernel_irq_routing_entry *e, irq_set[KVM_NR_IRQCHIPS];
 173         int ret = -1, i = 0;
 174         struct kvm_irq_routing_table *irq_rt;
 175         struct hlist_node *n;
 176
 177         trace_kvm_set_irq(irq, level, irq_source_id);
 178
 179         /* Not possible to detect if the guest uses the PIC or the
 180          * IOAPIC.  So set the bit in both. The guest will ignore
 181          * writes to the unused one.
 182          */
 183         rcu_read_lock();
 184         irq_rt = rcu_dereference(kvm->irq_routing);
 185         if (irq < irq_rt->nr_rt_entries)
 186                 hlist_for_each_entry(e, n, &irq_rt->map[irq], link)
 187                         irq_set[i++] = *e;
 188         rcu_read_unlock();
 189
 190         while(i--) {
 191                 int r;
 192                 r = irq_set[i].set(&irq_set[i], kvm, irq_source_id, level);
 193                 if (r < 0)
 194                         continue;
 195
 196                 ret = r + ((ret < 0) ? 0 : ret);
 197         }
 198
 199         return ret;
 200 }
 201
 202 /*
 203  * Deliver an IRQ in an atomic context if we can, or return a failure,
 204  * user can retry in a process context.
 205  * Return value:
 206  *  -EWOULDBLOCK - Can't deliver in atomic context: retry in a process context.
 207  *  Other values - No need to retry.
 208  */
 209 int kvm_set_irq_inatomic(struct kvm *kvm, int irq_source_id, u32 irq, int level)
 210 {
 211         struct kvm_kernel_irq_routing_entry *e;
 212         int ret = -EINVAL;
 213         struct kvm_irq_routing_table *irq_rt;
 214         struct hlist_node *n;
 215
 216         trace_kvm_set_irq(irq, level, irq_source_id);
 217
 218         /*
 219          * Injection into either PIC or IOAPIC might need to scan all CPUs,
 220          * which would need to be retried from thread context;  when same GSI
 221          * is connected to both PIC and IOAPIC, we'd have to report a
 222          * partial failure here.
 223          * Since there's no easy way to do this, we only support injecting MSI
 224          * which is limited to 1:1 GSI mapping.
 225          */
 226         rcu_read_lock();
 227         irq_rt = rcu_dereference(kvm->irq_routing);
 228         if (irq < irq_rt->nr_rt_entries)
 229                 hlist_for_each_entry(e, n, &irq_rt->map[irq], link) {
 230                         if (likely(e->type == KVM_IRQ_ROUTING_MSI))
 231                                 ret = kvm_set_msi_inatomic(e, kvm);
 232                         else
 233                                 ret = -EWOULDBLOCK;
 234                         break;
 235                 }
 236         rcu_read_unlock();
 237         return ret;
 238 }
 239
 240 void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
 241 {
 242         struct kvm_irq_ack_notifier *kian;
 243         struct hlist_node *n;
 244         int gsi;
 245
 246         trace_kvm_ack_irq(irqchip, pin);
 247
 248         rcu_read_lock();
 249         gsi = rcu_dereference(kvm->irq_routing)->chip[irqchip][pin];
 250         if (gsi != -1)
 251                 hlist_for_each_entry_rcu(kian, n, &kvm->irq_ack_notifier_list,
 252                                          link)
 253                         if (kian->gsi == gsi)
 254                                 kian->irq_acked(kian);
 255         rcu_read_unlock();
 256 }
 257
 258 void kvm_register_irq_ack_notifier(struct kvm *kvm,
 259                                    struct kvm_irq_ack_notifier *kian)
 260 {
 261         mutex_lock(&kvm->irq_lock);
 262         hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list);
 263         mutex_unlock(&kvm->irq_lock);
 264 }
 265
 266 void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
 267                                     struct kvm_irq_ack_notifier *kian)
 268 {
 269         mutex_lock(&kvm->irq_lock);
 270         hlist_del_init_rcu(&kian->link);
 271         mutex_unlock(&kvm->irq_lock);
 272         synchronize_rcu();
 273 }
 274
 275 int kvm_request_irq_source_id(struct kvm *kvm)
 276 {
 277         unsigned long *bitmap = &kvm->arch.irq_sources_bitmap;
 278         int irq_source_id;
 279
 280         mutex_lock(&kvm->irq_lock);
 281         irq_source_id = find_first_zero_bit(bitmap, BITS_PER_LONG);
 282
 283         if (irq_source_id >= BITS_PER_LONG) {
 284                 printk(KERN_WARNING "kvm: exhaust allocatable IRQ sources!\n");
 285                 irq_source_id = -EFAULT;
 286                 goto unlock;
 287         }
 288
 289         ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
 290 #ifdef CONFIG_X86
 291         ASSERT(irq_source_id != KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID);
 292 #endif
 293         set_bit(irq_source_id, bitmap);
 294 unlock:
 295         mutex_unlock(&kvm->irq_lock);
 296
 297         return irq_source_id;
 298 }
 299
 300 void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id)
 301 {
 302         ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
 303 #ifdef CONFIG_X86
 304         ASSERT(irq_source_id != KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID);
 305 #endif
 306
 307         mutex_lock(&kvm->irq_lock);
 308         if (irq_source_id < 0 ||
 309             irq_source_id >= BITS_PER_LONG) {
 310                 printk(KERN_ERR "kvm: IRQ source ID out of range!\n");
 311                 goto unlock;
 312         }
 313         clear_bit(irq_source_id, &kvm->arch.irq_sources_bitmap);
 314         if (!irqchip_in_kernel(kvm))
 315                 goto unlock;
 316
 317         kvm_ioapic_clear_all(kvm->arch.vioapic, irq_source_id);
 318 #ifdef CONFIG_X86
 319         kvm_pic_clear_all(pic_irqchip(kvm), irq_source_id);
 320 #endif
 321 unlock:
 322         mutex_unlock(&kvm->irq_lock);
 323 }
 324
 325 void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq,
 326                                     struct kvm_irq_mask_notifier *kimn)
 327 {
 328         mutex_lock(&kvm->irq_lock);
 329         kimn->irq = irq;
 330         hlist_add_head_rcu(&kimn->link, &kvm->mask_notifier_list);
 331         mutex_unlock(&kvm->irq_lock);
 332 }
 333
 334 void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq,
 335                                       struct kvm_irq_mask_notifier *kimn)
 336 {
 337         mutex_lock(&kvm->irq_lock);
 338         hlist_del_rcu(&kimn->link);
 339         mutex_unlock(&kvm->irq_lock);
 340         synchronize_rcu();
 341 }
 342
 343 void kvm_fire_mask_notifiers(struct kvm *kvm, unsigned irqchip, unsigned pin,
 344                              bool mask)
 345 {
 346         struct kvm_irq_mask_notifier *kimn;
 347         struct hlist_node *n;
 348         int gsi;
 349
 350         rcu_read_lock();
 351         gsi = rcu_dereference(kvm->irq_routing)->chip[irqchip][pin];
 352         if (gsi != -1)
 353                 hlist_for_each_entry_rcu(kimn, n, &kvm->mask_notifier_list, link)
 354                         if (kimn->irq == gsi)
 355                                 kimn->func(kimn, mask);
 356         rcu_read_unlock();
 357 }
 358
 359 void kvm_free_irq_routing(struct kvm *kvm)
 360 {
 361         /* Called only during vm destruction. Nobody can use the pointer
 362            at this stage */
 363         kfree(kvm->irq_routing);
 364 }
 365
 366 static int setup_routing_entry(struct kvm_irq_routing_table *rt,
 367                                struct kvm_kernel_irq_routing_entry *e,
 368                                const struct kvm_irq_routing_entry *ue)
 369 {
 370         int r = -EINVAL;
 371         int delta;
 372         unsigned max_pin;
 373         struct kvm_kernel_irq_routing_entry *ei;
 374         struct hlist_node *n;
 375
 376         /*
 377          * Do not allow GSI to be mapped to the same irqchip more than once.
 378          * Allow only one to one mapping between GSI and MSI.
 379          */
 380         hlist_for_each_entry(ei, n, &rt->map[ue->gsi], link)
 381                 if (ei->type == KVM_IRQ_ROUTING_MSI ||
 382                     ue->type == KVM_IRQ_ROUTING_MSI ||
 383                     ue->u.irqchip.irqchip == ei->irqchip.irqchip)
 384                         return r;
 385
 386         e->gsi = ue->gsi;
 387         e->type = ue->type;
 388         switch (ue->type) {
 389         case KVM_IRQ_ROUTING_IRQCHIP:
 390                 delta = 0;
 391                 switch (ue->u.irqchip.irqchip) {
 392                 case KVM_IRQCHIP_PIC_MASTER:
 393                         e->set = kvm_set_pic_irq;
 394                         max_pin = PIC_NUM_PINS;
 395                         break;
 396                 case KVM_IRQCHIP_PIC_SLAVE:
 397                         e->set = kvm_set_pic_irq;
 398                         max_pin = PIC_NUM_PINS;
 399                         delta = 8;
 400                         break;
 401                 case KVM_IRQCHIP_IOAPIC:
 402                         max_pin = KVM_IOAPIC_NUM_PINS;
 403                         e->set = kvm_set_ioapic_irq;
 404                         break;
 405                 default:
 406                         goto out;
 407                 }
 408                 e->irqchip.irqchip = ue->u.irqchip.irqchip;
 409                 e->irqchip.pin = ue->u.irqchip.pin + delta;
 410                 if (e->irqchip.pin >= max_pin)
 411                         goto out;
 412                 rt->chip[ue->u.irqchip.irqchip][e->irqchip.pin] = ue->gsi;
 413                 break;
 414         case KVM_IRQ_ROUTING_MSI:
 415                 e->set = kvm_set_msi;
 416                 e->msi.address_lo = ue->u.msi.address_lo;
 417                 e->msi.address_hi = ue->u.msi.address_hi;
 418                 e->msi.data = ue->u.msi.data;
 419                 break;
 420         default:
 421                 goto out;
 422         }
 423
 424         hlist_add_head(&e->link, &rt->map[e->gsi]);
 425         r = 0;
 426 out:
 427         return r;
 428 }
 429
 430
 431 int kvm_set_irq_routing(struct kvm *kvm,
 432                         const struct kvm_irq_routing_entry *ue,
 433                         unsigned nr,
 434                         unsigned flags)
 435 {
 436         struct kvm_irq_routing_table *new, *old;
 437         u32 i, j, nr_rt_entries = 0;
 438         int r;
 439
 440         for (i = 0; i < nr; ++i) {
 441                 if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
 442                         return -EINVAL;
 443                 nr_rt_entries = max(nr_rt_entries, ue[i].gsi);
 444         }
 445
 446         nr_rt_entries += 1;
 447
 448         new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head))
 449                       + (nr * sizeof(struct kvm_kernel_irq_routing_entry)),
 450                       GFP_KERNEL);
 451
 452         if (!new)
 453                 return -ENOMEM;
 454
 455         new->rt_entries = (void *)&new->map[nr_rt_entries];
 456
 457         new->nr_rt_entries = nr_rt_entries;
 458         for (i = 0; i < 3; i++)
 459                 for (j = 0; j < KVM_IOAPIC_NUM_PINS; j++)
 460                         new->chip[i][j] = -1;
 461
 462         for (i = 0; i < nr; ++i) {
 463                 r = -EINVAL;
 464                 if (ue->flags)
 465                         goto out;
 466                 r = setup_routing_entry(new, &new->rt_entries[i], ue);
 467                 if (r)
 468                         goto out;
 469                 ++ue;
 470         }
 471
 472         mutex_lock(&kvm->irq_lock);
 473         old = kvm->irq_routing;
 474         kvm_irq_routing_update(kvm, new);
 475         mutex_unlock(&kvm->irq_lock);
 476
 477         synchronize_rcu();
 478
 479         new = old;
 480         r = 0;
 481
 482 out:
 483         kfree(new);
 484         return r;
 485 }
 486
 487 #define IOAPIC_ROUTING_ENTRY(irq) \
 488         { .gsi = irq, .type = KVM_IRQ_ROUTING_IRQCHIP,  \
 489           .u.irqchip.irqchip = KVM_IRQCHIP_IOAPIC, .u.irqchip.pin = (irq) }
 490 #define ROUTING_ENTRY1(irq) IOAPIC_ROUTING_ENTRY(irq)
 491
 492 #ifdef CONFIG_X86
 493 #  define PIC_ROUTING_ENTRY(irq) \
 494         { .gsi = irq, .type = KVM_IRQ_ROUTING_IRQCHIP,  \
 495           .u.irqchip.irqchip = SELECT_PIC(irq), .u.irqchip.pin = (irq) % 8 }
 496 #  define ROUTING_ENTRY2(irq) \
 497         IOAPIC_ROUTING_ENTRY(irq), PIC_ROUTING_ENTRY(irq)
 498 #else
 499 #  define ROUTING_ENTRY2(irq) \
 500         IOAPIC_ROUTING_ENTRY(irq)
 501 #endif
 502
 503 static const struct kvm_irq_routing_entry default_routing[] = {
 504         ROUTING_ENTRY2(0), ROUTING_ENTRY2(1),
 505         ROUTING_ENTRY2(2), ROUTING_ENTRY2(3),
 506         ROUTING_ENTRY2(4), ROUTING_ENTRY2(5),
 507         ROUTING_ENTRY2(6), ROUTING_ENTRY2(7),
 508         ROUTING_ENTRY2(8), ROUTING_ENTRY2(9),
 509         ROUTING_ENTRY2(10), ROUTING_ENTRY2(11),
 510         ROUTING_ENTRY2(12), ROUTING_ENTRY2(13),
 511         ROUTING_ENTRY2(14), ROUTING_ENTRY2(15),
 512         ROUTING_ENTRY1(16), ROUTING_ENTRY1(17),
 513         ROUTING_ENTRY1(18), ROUTING_ENTRY1(19),
 514         ROUTING_ENTRY1(20), ROUTING_ENTRY1(21),
 515         ROUTING_ENTRY1(22), ROUTING_ENTRY1(23),
 516 #ifdef CONFIG_IA64
 517         ROUTING_ENTRY1(24), ROUTING_ENTRY1(25),
 518         ROUTING_ENTRY1(26), ROUTING_ENTRY1(27),
 519         ROUTING_ENTRY1(28), ROUTING_ENTRY1(29),
 520         ROUTING_ENTRY1(30), ROUTING_ENTRY1(31),
 521         ROUTING_ENTRY1(32), ROUTING_ENTRY1(33),
 522         ROUTING_ENTRY1(34), ROUTING_ENTRY1(35),
 523         ROUTING_ENTRY1(36), ROUTING_ENTRY1(37),
 524         ROUTING_ENTRY1(38), ROUTING_ENTRY1(39),
 525         ROUTING_ENTRY1(40), ROUTING_ENTRY1(41),
 526         ROUTING_ENTRY1(42), ROUTING_ENTRY1(43),
 527         ROUTING_ENTRY1(44), ROUTING_ENTRY1(45),
 528         ROUTING_ENTRY1(46), ROUTING_ENTRY1(47),
 529 #endif
 530 };
 531
 532 int kvm_setup_default_irq_routing(struct kvm *kvm)
 533 {
 534         return kvm_set_irq_routing(kvm, default_routing,
 535                                    ARRAY_SIZE(default_routing), 0);
 536 }