virt/kvm/arm/vgic/vgic.c

   1 /*
   2  * Copyright (C) 2015, 2016 ARM Ltd.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <linux/kvm.h>
  18 #include <linux/kvm_host.h>
  19 #include <linux/list_sort.h>
  20
  21 #include "vgic.h"
  22
  23 #define CREATE_TRACE_POINTS
  24 #include "trace.h"
  25
  26 #ifdef CONFIG_DEBUG_SPINLOCK
  27 #define DEBUG_SPINLOCK_BUG_ON(p) BUG_ON(p)
  28 #else
  29 #define DEBUG_SPINLOCK_BUG_ON(p)
  30 #endif
  31
  32 struct vgic_global kvm_vgic_global_state __ro_after_init = {
  33         .gicv3_cpuif = STATIC_KEY_FALSE_INIT,
  34 };
  35
  36 /*
  37  * Locking order is always:
  38  * kvm->lock (mutex)
  39  *   its->cmd_lock (mutex)
  40  *     its->its_lock (mutex)
  41  *       vgic_cpu->ap_list_lock
  42  *         kvm->lpi_list_lock
  43  *           vgic_irq->irq_lock
  44  *
  45  * If you need to take multiple locks, always take the upper lock first,
  46  * then the lower ones, e.g. first take the its_lock, then the irq_lock.
  47  * If you are already holding a lock and need to take a higher one, you
  48  * have to drop the lower ranking lock first and re-aquire it after having
  49  * taken the upper one.
  50  *
  51  * When taking more than one ap_list_lock at the same time, always take the
  52  * lowest numbered VCPU's ap_list_lock first, so:
  53  *   vcpuX->vcpu_id < vcpuY->vcpu_id:
  54  *     spin_lock(vcpuX->arch.vgic_cpu.ap_list_lock);
  55  *     spin_lock(vcpuY->arch.vgic_cpu.ap_list_lock);
  56  */
  57
  58 /*
  59  * Iterate over the VM's list of mapped LPIs to find the one with a
  60  * matching interrupt ID and return a reference to the IRQ structure.
  61  */
  62 static struct vgic_irq *vgic_get_lpi(struct kvm *kvm, u32 intid)
  63 {
  64         struct vgic_dist *dist = &kvm->arch.vgic;
  65         struct vgic_irq *irq = NULL;
  66
  67         spin_lock(&dist->lpi_list_lock);
  68
  69         list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
  70                 if (irq->intid != intid)
  71                         continue;
  72
  73                 /*
  74                  * This increases the refcount, the caller is expected to
  75                  * call vgic_put_irq() later once it's finished with the IRQ.
  76                  */
  77                 vgic_get_irq_kref(irq);
  78                 goto out_unlock;
  79         }
  80         irq = NULL;
  81
  82 out_unlock:
  83         spin_unlock(&dist->lpi_list_lock);
  84
  85         return irq;
  86 }
  87
  88 /*
  89  * This looks up the virtual interrupt ID to get the corresponding
  90  * struct vgic_irq. It also increases the refcount, so any caller is expected
  91  * to call vgic_put_irq() once it's finished with this IRQ.
  92  */
  93 struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
  94                               u32 intid)
  95 {
  96         /* SGIs and PPIs */
  97         if (intid <= VGIC_MAX_PRIVATE)
  98                 return &vcpu->arch.vgic_cpu.private_irqs[intid];
  99
 100         /* SPIs */
 101         if (intid <= VGIC_MAX_SPI)
 102                 return &kvm->arch.vgic.spis[intid - VGIC_NR_PRIVATE_IRQS];
 103
 104         /* LPIs */
 105         if (intid >= VGIC_MIN_LPI)
 106                 return vgic_get_lpi(kvm, intid);
 107
 108         WARN(1, "Looking up struct vgic_irq for reserved INTID");
 109         return NULL;
 110 }
 111
 112 /*
 113  * We can't do anything in here, because we lack the kvm pointer to
 114  * lock and remove the item from the lpi_list. So we keep this function
 115  * empty and use the return value of kref_put() to trigger the freeing.
 116  */
 117 static void vgic_irq_release(struct kref *ref)
 118 {
 119 }
 120
 121 void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq)
 122 {
 123         struct vgic_dist *dist = &kvm->arch.vgic;
 124
 125         if (irq->intid < VGIC_MIN_LPI)
 126                 return;
 127
 128         spin_lock(&dist->lpi_list_lock);
 129         if (!kref_put(&irq->refcount, vgic_irq_release)) {
 130                 spin_unlock(&dist->lpi_list_lock);
 131                 return;
 132         };
 133
 134         list_del(&irq->lpi_list);
 135         dist->lpi_list_count--;
 136         spin_unlock(&dist->lpi_list_lock);
 137
 138         kfree(irq);
 139 }
 140
 141 /**
 142  * kvm_vgic_target_oracle - compute the target vcpu for an irq
 143  *
 144  * @irq:        The irq to route. Must be already locked.
 145  *
 146  * Based on the current state of the interrupt (enabled, pending,
 147  * active, vcpu and target_vcpu), compute the next vcpu this should be
 148  * given to. Return NULL if this shouldn't be injected at all.
 149  *
 150  * Requires the IRQ lock to be held.
 151  */
 152 static struct kvm_vcpu *vgic_target_oracle(struct vgic_irq *irq)
 153 {
 154         DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&irq->irq_lock));
 155
 156         /* If the interrupt is active, it must stay on the current vcpu */
 157         if (irq->active)
 158                 return irq->vcpu ? : irq->target_vcpu;
 159
 160         /*
 161          * If the IRQ is not active but enabled and pending, we should direct
 162          * it to its configured target VCPU.
 163          * If the distributor is disabled, pending interrupts shouldn't be
 164          * forwarded.
 165          */
 166         if (irq->enabled && irq_is_pending(irq)) {
 167                 if (unlikely(irq->target_vcpu &&
 168                              !irq->target_vcpu->kvm->arch.vgic.enabled))
 169                         return NULL;
 170
 171                 return irq->target_vcpu;
 172         }
 173
 174         /* If neither active nor pending and enabled, then this IRQ should not
 175          * be queued to any VCPU.
 176          */
 177         return NULL;
 178 }
 179
 180 /*
 181  * The order of items in the ap_lists defines how we'll pack things in LRs as
 182  * well, the first items in the list being the first things populated in the
 183  * LRs.
 184  *
 185  * A hard rule is that active interrupts can never be pushed out of the LRs
 186  * (and therefore take priority) since we cannot reliably trap on deactivation
 187  * of IRQs and therefore they have to be present in the LRs.
 188  *
 189  * Otherwise things should be sorted by the priority field and the GIC
 190  * hardware support will take care of preemption of priority groups etc.
 191  *
 192  * Return negative if "a" sorts before "b", 0 to preserve order, and positive
 193  * to sort "b" before "a".
 194  */
 195 static int vgic_irq_cmp(void *priv, struct list_head *a, struct list_head *b)
 196 {
 197         struct vgic_irq *irqa = container_of(a, struct vgic_irq, ap_list);
 198         struct vgic_irq *irqb = container_of(b, struct vgic_irq, ap_list);
 199         bool penda, pendb;
 200         int ret;
 201
 202         /*
 203          * list_sort may call this function with the same element when
 204          * the list is fairly long.
 205          */
 206         if (unlikely(irqa == irqb))
 207                 return 0;
 208
 209         spin_lock(&irqa->irq_lock);
 210         spin_lock_nested(&irqb->irq_lock, SINGLE_DEPTH_NESTING);
 211
 212         if (irqa->active || irqb->active) {
 213                 ret = (int)irqb->active - (int)irqa->active;
 214                 goto out;
 215         }
 216
 217         penda = irqa->enabled && irq_is_pending(irqa);
 218         pendb = irqb->enabled && irq_is_pending(irqb);
 219
 220         if (!penda || !pendb) {
 221                 ret = (int)pendb - (int)penda;
 222                 goto out;
 223         }
 224
 225         /* Both pending and enabled, sort by priority */
 226         ret = irqa->priority - irqb->priority;
 227 out:
 228         spin_unlock(&irqb->irq_lock);
 229         spin_unlock(&irqa->irq_lock);
 230         return ret;
 231 }
 232
 233 /* Must be called with the ap_list_lock held */
 234 static void vgic_sort_ap_list(struct kvm_vcpu *vcpu)
 235 {
 236         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 237
 238         DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&vgic_cpu->ap_list_lock));
 239
 240         list_sort(NULL, &vgic_cpu->ap_list_head, vgic_irq_cmp);
 241 }
 242
 243 /*
 244  * Only valid injection if changing level for level-triggered IRQs or for a
 245  * rising edge, and in-kernel connected IRQ lines can only be controlled by
 246  * their owner.
 247  */
 248 static bool vgic_validate_injection(struct vgic_irq *irq, bool level, void *owner)
 249 {
 250         if (irq->owner != owner)
 251                 return false;
 252
 253         switch (irq->config) {
 254         case VGIC_CONFIG_LEVEL:
 255                 return irq->line_level != level;
 256         case VGIC_CONFIG_EDGE:
 257                 return level;
 258         }
 259
 260         return false;
 261 }
 262
 263 /*
 264  * Check whether an IRQ needs to (and can) be queued to a VCPU's ap list.
 265  * Do the queuing if necessary, taking the right locks in the right order.
 266  * Returns true when the IRQ was queued, false otherwise.
 267  *
 268  * Needs to be entered with the IRQ lock already held, but will return
 269  * with all locks dropped.
 270  */
 271 bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq)
 272 {
 273         struct kvm_vcpu *vcpu;
 274
 275         DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&irq->irq_lock));
 276
 277 retry:
 278         vcpu = vgic_target_oracle(irq);
 279         if (irq->vcpu || !vcpu) {
 280                 /*
 281                  * If this IRQ is already on a VCPU's ap_list, then it
 282                  * cannot be moved or modified and there is no more work for
 283                  * us to do.
 284                  *
 285                  * Otherwise, if the irq is not pending and enabled, it does
 286                  * not need to be inserted into an ap_list and there is also
 287                  * no more work for us to do.
 288                  */
 289                 spin_unlock(&irq->irq_lock);
 290
 291                 /*
 292                  * We have to kick the VCPU here, because we could be
 293                  * queueing an edge-triggered interrupt for which we
 294                  * get no EOI maintenance interrupt. In that case,
 295                  * while the IRQ is already on the VCPU's AP list, the
 296                  * VCPU could have EOI'ed the original interrupt and
 297                  * won't see this one until it exits for some other
 298                  * reason.
 299                  */
 300                 if (vcpu) {
 301                         kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
 302                         kvm_vcpu_kick(vcpu);
 303                 }
 304                 return false;
 305         }
 306
 307         /*
 308          * We must unlock the irq lock to take the ap_list_lock where
 309          * we are going to insert this new pending interrupt.
 310          */
 311         spin_unlock(&irq->irq_lock);
 312
 313         /* someone can do stuff here, which we re-check below */
 314
 315         spin_lock(&vcpu->arch.vgic_cpu.ap_list_lock);
 316         spin_lock(&irq->irq_lock);
 317
 318         /*
 319          * Did something change behind our backs?
 320          *
 321          * There are two cases:
 322          * 1) The irq lost its pending state or was disabled behind our
 323          *    backs and/or it was queued to another VCPU's ap_list.
 324          * 2) Someone changed the affinity on this irq behind our
 325          *    backs and we are now holding the wrong ap_list_lock.
 326          *
 327          * In both cases, drop the locks and retry.
 328          */
 329
 330         if (unlikely(irq->vcpu || vcpu != vgic_target_oracle(irq))) {
 331                 spin_unlock(&irq->irq_lock);
 332                 spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock);
 333
 334                 spin_lock(&irq->irq_lock);
 335                 goto retry;
 336         }
 337
 338         /*
 339          * Grab a reference to the irq to reflect the fact that it is
 340          * now in the ap_list.
 341          */
 342         vgic_get_irq_kref(irq);
 343         list_add_tail(&irq->ap_list, &vcpu->arch.vgic_cpu.ap_list_head);
 344         irq->vcpu = vcpu;
 345
 346         spin_unlock(&irq->irq_lock);
 347         spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock);
 348
 349         kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
 350         kvm_vcpu_kick(vcpu);
 351
 352         return true;
 353 }
 354
 355 /**
 356  * kvm_vgic_inject_irq - Inject an IRQ from a device to the vgic
 357  * @kvm:     The VM structure pointer
 358  * @cpuid:   The CPU for PPIs
 359  * @intid:   The INTID to inject a new state to.
 360  * @level:   Edge-triggered:  true:  to trigger the interrupt
 361  *                            false: to ignore the call
 362  *           Level-sensitive  true:  raise the input signal
 363  *                            false: lower the input signal
 364  * @owner:   The opaque pointer to the owner of the IRQ being raised to verify
 365  *           that the caller is allowed to inject this IRQ.  Userspace
 366  *           injections will have owner == NULL.
 367  *
 368  * The VGIC is not concerned with devices being active-LOW or active-HIGH for
 369  * level-sensitive interrupts.  You can think of the level parameter as 1
 370  * being HIGH and 0 being LOW and all devices being active-HIGH.
 371  */
 372 int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
 373                         bool level, void *owner)
 374 {
 375         struct kvm_vcpu *vcpu;
 376         struct vgic_irq *irq;
 377         int ret;
 378
 379         trace_vgic_update_irq_pending(cpuid, intid, level);
 380
 381         ret = vgic_lazy_init(kvm);
 382         if (ret)
 383                 return ret;
 384
 385         vcpu = kvm_get_vcpu(kvm, cpuid);
 386         if (!vcpu && intid < VGIC_NR_PRIVATE_IRQS)
 387                 return -EINVAL;
 388
 389         irq = vgic_get_irq(kvm, vcpu, intid);
 390         if (!irq)
 391                 return -EINVAL;
 392
 393         spin_lock(&irq->irq_lock);
 394
 395         if (!vgic_validate_injection(irq, level, owner)) {
 396                 /* Nothing to see here, move along... */
 397                 spin_unlock(&irq->irq_lock);
 398                 vgic_put_irq(kvm, irq);
 399                 return 0;
 400         }
 401
 402         if (irq->config == VGIC_CONFIG_LEVEL)
 403                 irq->line_level = level;
 404         else
 405                 irq->pending_latch = true;
 406
 407         vgic_queue_irq_unlock(kvm, irq);
 408         vgic_put_irq(kvm, irq);
 409
 410         return 0;
 411 }
 412
 413 int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, u32 virt_irq, u32 phys_irq)
 414 {
 415         struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, virt_irq);
 416
 417         BUG_ON(!irq);
 418
 419         spin_lock(&irq->irq_lock);
 420
 421         irq->hw = true;
 422         irq->hwintid = phys_irq;
 423
 424         spin_unlock(&irq->irq_lock);
 425         vgic_put_irq(vcpu->kvm, irq);
 426
 427         return 0;
 428 }
 429
 430 int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int virt_irq)
 431 {
 432         struct vgic_irq *irq;
 433
 434         if (!vgic_initialized(vcpu->kvm))
 435                 return -EAGAIN;
 436
 437         irq = vgic_get_irq(vcpu->kvm, vcpu, virt_irq);
 438         BUG_ON(!irq);
 439
 440         spin_lock(&irq->irq_lock);
 441
 442         irq->hw = false;
 443         irq->hwintid = 0;
 444
 445         spin_unlock(&irq->irq_lock);
 446         vgic_put_irq(vcpu->kvm, irq);
 447
 448         return 0;
 449 }
 450
 451 /**
 452  * kvm_vgic_set_owner - Set the owner of an interrupt for a VM
 453  *
 454  * @vcpu:   Pointer to the VCPU (used for PPIs)
 455  * @intid:  The virtual INTID identifying the interrupt (PPI or SPI)
 456  * @owner:  Opaque pointer to the owner
 457  *
 458  * Returns 0 if intid is not already used by another in-kernel device and the
 459  * owner is set, otherwise returns an error code.
 460  */
 461 int kvm_vgic_set_owner(struct kvm_vcpu *vcpu, unsigned int intid, void *owner)
 462 {
 463         struct vgic_irq *irq;
 464         unsigned long flags;
 465         int ret = 0;
 466
 467         if (!vgic_initialized(vcpu->kvm))
 468                 return -EAGAIN;
 469
 470         /* SGIs and LPIs cannot be wired up to any device */
 471         if (!irq_is_ppi(intid) && !vgic_valid_spi(vcpu->kvm, intid))
 472                 return -EINVAL;
 473
 474         irq = vgic_get_irq(vcpu->kvm, vcpu, intid);
 475         spin_lock_irqsave(&irq->irq_lock, flags);
 476         if (irq->owner && irq->owner != owner)
 477                 ret = -EEXIST;
 478         else
 479                 irq->owner = owner;
 480         spin_unlock_irqrestore(&irq->irq_lock, flags);
 481
 482         return ret;
 483 }
 484
 485 /**
 486  * vgic_prune_ap_list - Remove non-relevant interrupts from the list
 487  *
 488  * @vcpu: The VCPU pointer
 489  *
 490  * Go over the list of "interesting" interrupts, and prune those that we
 491  * won't have to consider in the near future.
 492  */
 493 static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)
 494 {
 495         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 496         struct vgic_irq *irq, *tmp;
 497
 498 retry:
 499         spin_lock(&vgic_cpu->ap_list_lock);
 500
 501         list_for_each_entry_safe(irq, tmp, &vgic_cpu->ap_list_head, ap_list) {
 502                 struct kvm_vcpu *target_vcpu, *vcpuA, *vcpuB;
 503
 504                 spin_lock(&irq->irq_lock);
 505
 506                 BUG_ON(vcpu != irq->vcpu);
 507
 508                 target_vcpu = vgic_target_oracle(irq);
 509
 510                 if (!target_vcpu) {
 511                         /*
 512                          * We don't need to process this interrupt any
 513                          * further, move it off the list.
 514                          */
 515                         list_del(&irq->ap_list);
 516                         irq->vcpu = NULL;
 517                         spin_unlock(&irq->irq_lock);
 518
 519                         /*
 520                          * This vgic_put_irq call matches the
 521                          * vgic_get_irq_kref in vgic_queue_irq_unlock,
 522                          * where we added the LPI to the ap_list. As
 523                          * we remove the irq from the list, we drop
 524                          * also drop the refcount.
 525                          */
 526                         vgic_put_irq(vcpu->kvm, irq);
 527                         continue;
 528                 }
 529
 530                 if (target_vcpu == vcpu) {
 531                         /* We're on the right CPU */
 532                         spin_unlock(&irq->irq_lock);
 533                         continue;
 534                 }
 535
 536                 /* This interrupt looks like it has to be migrated. */
 537
 538                 spin_unlock(&irq->irq_lock);
 539                 spin_unlock(&vgic_cpu->ap_list_lock);
 540
 541                 /*
 542                  * Ensure locking order by always locking the smallest
 543                  * ID first.
 544                  */
 545                 if (vcpu->vcpu_id < target_vcpu->vcpu_id) {
 546                         vcpuA = vcpu;
 547                         vcpuB = target_vcpu;
 548                 } else {
 549                         vcpuA = target_vcpu;
 550                         vcpuB = vcpu;
 551                 }
 552
 553                 spin_lock(&vcpuA->arch.vgic_cpu.ap_list_lock);
 554                 spin_lock_nested(&vcpuB->arch.vgic_cpu.ap_list_lock,
 555                                  SINGLE_DEPTH_NESTING);
 556                 spin_lock(&irq->irq_lock);
 557
 558                 /*
 559                  * If the affinity has been preserved, move the
 560                  * interrupt around. Otherwise, it means things have
 561                  * changed while the interrupt was unlocked, and we
 562                  * need to replay this.
 563                  *
 564                  * In all cases, we cannot trust the list not to have
 565                  * changed, so we restart from the beginning.
 566                  */
 567                 if (target_vcpu == vgic_target_oracle(irq)) {
 568                         struct vgic_cpu *new_cpu = &target_vcpu->arch.vgic_cpu;
 569
 570                         list_del(&irq->ap_list);
 571                         irq->vcpu = target_vcpu;
 572                         list_add_tail(&irq->ap_list, &new_cpu->ap_list_head);
 573                 }
 574
 575                 spin_unlock(&irq->irq_lock);
 576                 spin_unlock(&vcpuB->arch.vgic_cpu.ap_list_lock);
 577                 spin_unlock(&vcpuA->arch.vgic_cpu.ap_list_lock);
 578                 goto retry;
 579         }
 580
 581         spin_unlock(&vgic_cpu->ap_list_lock);
 582 }
 583
 584 static inline void vgic_fold_lr_state(struct kvm_vcpu *vcpu)
 585 {
 586         if (kvm_vgic_global_state.type == VGIC_V2)
 587                 vgic_v2_fold_lr_state(vcpu);
 588         else
 589                 vgic_v3_fold_lr_state(vcpu);
 590 }
 591
 592 /* Requires the irq_lock to be held. */
 593 static inline void vgic_populate_lr(struct kvm_vcpu *vcpu,
 594                                     struct vgic_irq *irq, int lr)
 595 {
 596         DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&irq->irq_lock));
 597
 598         if (kvm_vgic_global_state.type == VGIC_V2)
 599                 vgic_v2_populate_lr(vcpu, irq, lr);
 600         else
 601                 vgic_v3_populate_lr(vcpu, irq, lr);
 602 }
 603
 604 static inline void vgic_clear_lr(struct kvm_vcpu *vcpu, int lr)
 605 {
 606         if (kvm_vgic_global_state.type == VGIC_V2)
 607                 vgic_v2_clear_lr(vcpu, lr);
 608         else
 609                 vgic_v3_clear_lr(vcpu, lr);
 610 }
 611
 612 static inline void vgic_set_underflow(struct kvm_vcpu *vcpu)
 613 {
 614         if (kvm_vgic_global_state.type == VGIC_V2)
 615                 vgic_v2_set_underflow(vcpu);
 616         else
 617                 vgic_v3_set_underflow(vcpu);
 618 }
 619
 620 static inline void vgic_set_npie(struct kvm_vcpu *vcpu)
 621 {
 622         if (kvm_vgic_global_state.type == VGIC_V2)
 623                 vgic_v2_set_npie(vcpu);
 624         else
 625                 vgic_v3_set_npie(vcpu);
 626 }
 627
 628 /* Requires the ap_list_lock to be held. */
 629 static int compute_ap_list_depth(struct kvm_vcpu *vcpu,
 630                                  bool *multi_sgi)
 631 {
 632         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 633         struct vgic_irq *irq;
 634         int count = 0;
 635
 636         *multi_sgi = false;
 637
 638         DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&vgic_cpu->ap_list_lock));
 639
 640         list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
 641                 spin_lock(&irq->irq_lock);
 642                 /* GICv2 SGIs can count for more than one... */
 643                 if (vgic_irq_is_sgi(irq->intid) && irq->source) {
 644                         int w = hweight8(irq->source);
 645
 646                         count += w;
 647                         *multi_sgi |= (w > 1);
 648                 } else {
 649                         count++;
 650                 }
 651                 spin_unlock(&irq->irq_lock);
 652         }
 653         return count;
 654 }
 655
 656 /* Requires the VCPU's ap_list_lock to be held. */
 657 static void vgic_flush_lr_state(struct kvm_vcpu *vcpu)
 658 {
 659         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 660         struct vgic_irq *irq;
 661         int count;
 662         bool npie = false;
 663         bool multi_sgi;
 664         u8 prio = 0xff;
 665
 666         DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&vgic_cpu->ap_list_lock));
 667
 668         count = compute_ap_list_depth(vcpu, &multi_sgi);
 669         if (count > kvm_vgic_global_state.nr_lr || multi_sgi)
 670                 vgic_sort_ap_list(vcpu);
 671
 672         count = 0;
 673
 674         list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
 675                 spin_lock(&irq->irq_lock);
 676
 677                 /*
 678                  * If we have multi-SGIs in the pipeline, we need to
 679                  * guarantee that they are all seen before any IRQ of
 680                  * lower priority. In that case, we need to filter out
 681                  * these interrupts by exiting early. This is easy as
 682                  * the AP list has been sorted already.
 683                  */
 684                 if (multi_sgi && irq->priority > prio) {
 685                         spin_unlock(&irq->irq_lock);
 686                         break;
 687                 }
 688
 689                 if (likely(vgic_target_oracle(irq) == vcpu)) {
 690                         vgic_populate_lr(vcpu, irq, count++);
 691
 692                         if (irq->source) {
 693                                 npie = true;
 694                                 prio = irq->priority;
 695                         }
 696                 }
 697
 698                 spin_unlock(&irq->irq_lock);
 699
 700                 if (count == kvm_vgic_global_state.nr_lr) {
 701                         if (!list_is_last(&irq->ap_list,
 702                                           &vgic_cpu->ap_list_head))
 703                                 vgic_set_underflow(vcpu);
 704                         break;
 705                 }
 706         }
 707
 708         if (npie)
 709                 vgic_set_npie(vcpu);
 710
 711         vcpu->arch.vgic_cpu.used_lrs = count;
 712
 713         /* Nuke remaining LRs */
 714         for ( ; count < kvm_vgic_global_state.nr_lr; count++)
 715                 vgic_clear_lr(vcpu, count);
 716 }
 717
 718 /* Sync back the hardware VGIC state into our emulation after a guest's run. */
 719 void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
 720 {
 721         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 722
 723         /* An empty ap_list_head implies used_lrs == 0 */
 724         if (list_empty(&vcpu->arch.vgic_cpu.ap_list_head))
 725                 return;
 726
 727         if (vgic_cpu->used_lrs)
 728                 vgic_fold_lr_state(vcpu);
 729         vgic_prune_ap_list(vcpu);
 730 }
 731
 732 /* Flush our emulation state into the GIC hardware before entering the guest. */
 733 void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
 734 {
 735         /*
 736          * If there are no virtual interrupts active or pending for this
 737          * VCPU, then there is no work to do and we can bail out without
 738          * taking any lock.  There is a potential race with someone injecting
 739          * interrupts to the VCPU, but it is a benign race as the VCPU will
 740          * either observe the new interrupt before or after doing this check,
 741          * and introducing additional synchronization mechanism doesn't change
 742          * this.
 743          */
 744         if (list_empty(&vcpu->arch.vgic_cpu.ap_list_head))
 745                 return;
 746
 747         spin_lock(&vcpu->arch.vgic_cpu.ap_list_lock);
 748         vgic_flush_lr_state(vcpu);
 749         spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock);
 750 }
 751
 752 void kvm_vgic_load(struct kvm_vcpu *vcpu)
 753 {
 754         if (unlikely(!vgic_initialized(vcpu->kvm)))
 755                 return;
 756
 757         if (kvm_vgic_global_state.type == VGIC_V2)
 758                 vgic_v2_load(vcpu);
 759         else
 760                 vgic_v3_load(vcpu);
 761 }
 762
 763 void kvm_vgic_put(struct kvm_vcpu *vcpu)
 764 {
 765         if (unlikely(!vgic_initialized(vcpu->kvm)))
 766                 return;
 767
 768         if (kvm_vgic_global_state.type == VGIC_V2)
 769                 vgic_v2_put(vcpu);
 770         else
 771                 vgic_v3_put(vcpu);
 772 }
 773
 774 void kvm_vgic_vmcr_sync(struct kvm_vcpu *vcpu)
 775 {
 776         if (unlikely(!irqchip_in_kernel(vcpu->kvm)))
 777                 return;
 778
 779         if (kvm_vgic_global_state.type == VGIC_V2)
 780                 vgic_v2_vmcr_sync(vcpu);
 781         else
 782                 vgic_v3_vmcr_sync(vcpu);
 783 }
 784
 785 int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu)
 786 {
 787         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 788         struct vgic_irq *irq;
 789         bool pending = false;
 790
 791         if (!vcpu->kvm->arch.vgic.enabled)
 792                 return false;
 793
 794         spin_lock(&vgic_cpu->ap_list_lock);
 795
 796         list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
 797                 spin_lock(&irq->irq_lock);
 798                 pending = irq_is_pending(irq) && irq->enabled;
 799                 spin_unlock(&irq->irq_lock);
 800
 801                 if (pending)
 802                         break;
 803         }
 804
 805         spin_unlock(&vgic_cpu->ap_list_lock);
 806
 807         return pending;
 808 }
 809
 810 void vgic_kick_vcpus(struct kvm *kvm)
 811 {
 812         struct kvm_vcpu *vcpu;
 813         int c;
 814
 815         /*
 816          * We've injected an interrupt, time to find out who deserves
 817          * a good kick...
 818          */
 819         kvm_for_each_vcpu(c, vcpu, kvm) {
 820                 if (kvm_vgic_vcpu_pending_irq(vcpu)) {
 821                         kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
 822                         kvm_vcpu_kick(vcpu);
 823                 }
 824         }
 825 }
 826
 827 bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int virt_irq)
 828 {
 829         struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, virt_irq);
 830         bool map_is_active;
 831
 832         spin_lock(&irq->irq_lock);
 833         map_is_active = irq->hw && irq->active;
 834         spin_unlock(&irq->irq_lock);
 835         vgic_put_irq(vcpu->kvm, irq);
 836
 837         return map_is_active;
 838 }
 839