linux/virt/kvm/arm/vgic/vgic.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (C) 2015, 2016 ARM Ltd.
   4 */
   5
   6#include <linux/interrupt.h>
   7#include <linux/irq.h>
   8#include <linux/kvm.h>
   9#include <linux/kvm_host.h>
  10#include <linux/list_sort.h>
  11#include <linux/nospec.h>
  12
  13#include <asm/kvm_hyp.h>
  14
  15#include "vgic.h"
  16
  17#define CREATE_TRACE_POINTS
  18#include "trace.h"
  19
  20struct vgic_global kvm_vgic_global_state __ro_after_init = {
  21        .gicv3_cpuif = STATIC_KEY_FALSE_INIT,
  22};
  23
  24/*
  25 * Locking order is always:
  26 * kvm->lock (mutex)
  27 *   its->cmd_lock (mutex)
  28 *     its->its_lock (mutex)
  29 *       vgic_cpu->ap_list_lock         must be taken with IRQs disabled
  30 *         kvm->lpi_list_lock           must be taken with IRQs disabled
  31 *           vgic_irq->irq_lock         must be taken with IRQs disabled
  32 *
  33 * As the ap_list_lock might be taken from the timer interrupt handler,
  34 * we have to disable IRQs before taking this lock and everything lower
  35 * than it.
  36 *
  37 * If you need to take multiple locks, always take the upper lock first,
  38 * then the lower ones, e.g. first take the its_lock, then the irq_lock.
  39 * If you are already holding a lock and need to take a higher one, you
  40 * have to drop the lower ranking lock first and re-aquire it after having
  41 * taken the upper one.
  42 *
  43 * When taking more than one ap_list_lock at the same time, always take the
  44 * lowest numbered VCPU's ap_list_lock first, so:
  45 *   vcpuX->vcpu_id < vcpuY->vcpu_id:
  46 *     raw_spin_lock(vcpuX->arch.vgic_cpu.ap_list_lock);
  47 *     raw_spin_lock(vcpuY->arch.vgic_cpu.ap_list_lock);
  48 *
  49 * Since the VGIC must support injecting virtual interrupts from ISRs, we have
  50 * to use the raw_spin_lock_irqsave/raw_spin_unlock_irqrestore versions of outer
  51 * spinlocks for any lock that may be taken while injecting an interrupt.
  52 */
  53
  54/*
  55 * Iterate over the VM's list of mapped LPIs to find the one with a
  56 * matching interrupt ID and return a reference to the IRQ structure.
  57 */
  58static struct vgic_irq *vgic_get_lpi(struct kvm *kvm, u32 intid)
  59{
  60        struct vgic_dist *dist = &kvm->arch.vgic;
  61        struct vgic_irq *irq = NULL;
  62        unsigned long flags;
  63
  64        raw_spin_lock_irqsave(&dist->lpi_list_lock, flags);
  65
  66        list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
  67                if (irq->intid != intid)
  68                        continue;
  69
  70                /*
  71                 * This increases the refcount, the caller is expected to
  72                 * call vgic_put_irq() later once it's finished with the IRQ.
  73                 */
  74                vgic_get_irq_kref(irq);
  75                goto out_unlock;
  76        }
  77        irq = NULL;
  78
  79out_unlock:
  80        raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
  81
  82        return irq;
  83}
  84
  85/*
  86 * This looks up the virtual interrupt ID to get the corresponding
  87 * struct vgic_irq. It also increases the refcount, so any caller is expected
  88 * to call vgic_put_irq() once it's finished with this IRQ.
  89 */
  90struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
  91                              u32 intid)
  92{
  93        /* SGIs and PPIs */
  94        if (intid <= VGIC_MAX_PRIVATE) {
  95                intid = array_index_nospec(intid, VGIC_MAX_PRIVATE + 1);
  96                return &vcpu->arch.vgic_cpu.private_irqs[intid];
  97        }
  98
  99        /* SPIs */
 100        if (intid < (kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS)) {
 101                intid = array_index_nospec(intid, kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS);
 102                return &kvm->arch.vgic.spis[intid - VGIC_NR_PRIVATE_IRQS];
 103        }
 104
 105        /* LPIs */
 106        if (intid >= VGIC_MIN_LPI)
 107                return vgic_get_lpi(kvm, intid);
 108
 109        WARN(1, "Looking up struct vgic_irq for reserved INTID");
 110        return NULL;
 111}
 112
 113/*
 114 * We can't do anything in here, because we lack the kvm pointer to
 115 * lock and remove the item from the lpi_list. So we keep this function
 116 * empty and use the return value of kref_put() to trigger the freeing.
 117 */
 118static void vgic_irq_release(struct kref *ref)
 119{
 120}
 121
 122/*
 123 * Drop the refcount on the LPI. Must be called with lpi_list_lock held.
 124 */
 125void __vgic_put_lpi_locked(struct kvm *kvm, struct vgic_irq *irq)
 126{
 127        struct vgic_dist *dist = &kvm->arch.vgic;
 128
 129        if (!kref_put(&irq->refcount, vgic_irq_release))
 130                return;
 131
 132        list_del(&irq->lpi_list);
 133        dist->lpi_list_count--;
 134
 135        kfree(irq);
 136}
 137
 138void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq)
 139{
 140        struct vgic_dist *dist = &kvm->arch.vgic;
 141        unsigned long flags;
 142
 143        if (irq->intid < VGIC_MIN_LPI)
 144                return;
 145
 146        raw_spin_lock_irqsave(&dist->lpi_list_lock, flags);
 147        __vgic_put_lpi_locked(kvm, irq);
 148        raw_spin_unlock_irqrestore(&dist->lpi_list_lock, flags);
 149}
 150
 151void vgic_flush_pending_lpis(struct kvm_vcpu *vcpu)
 152{
 153        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 154        struct vgic_irq *irq, *tmp;
 155        unsigned long flags;
 156
 157        raw_spin_lock_irqsave(&vgic_cpu->ap_list_lock, flags);
 158
 159        list_for_each_entry_safe(irq, tmp, &vgic_cpu->ap_list_head, ap_list) {
 160                if (irq->intid >= VGIC_MIN_LPI) {
 161                        raw_spin_lock(&irq->irq_lock);
 162                        list_del(&irq->ap_list);
 163                        irq->vcpu = NULL;
 164                        raw_spin_unlock(&irq->irq_lock);
 165                        vgic_put_irq(vcpu->kvm, irq);
 166                }
 167        }
 168
 169        raw_spin_unlock_irqrestore(&vgic_cpu->ap_list_lock, flags);
 170}
 171
 172void vgic_irq_set_phys_pending(struct vgic_irq *irq, bool pending)
 173{
 174        WARN_ON(irq_set_irqchip_state(irq->host_irq,
 175                                      IRQCHIP_STATE_PENDING,
 176                                      pending));
 177}
 178
 179bool vgic_get_phys_line_level(struct vgic_irq *irq)
 180{
 181        bool line_level;
 182
 183        BUG_ON(!irq->hw);
 184
 185        if (irq->get_input_level)
 186                return irq->get_input_level(irq->intid);
 187
 188        WARN_ON(irq_get_irqchip_state(irq->host_irq,
 189                                      IRQCHIP_STATE_PENDING,
 190                                      &line_level));
 191        return line_level;
 192}
 193
 194/* Set/Clear the physical active state */
 195void vgic_irq_set_phys_active(struct vgic_irq *irq, bool active)
 196{
 197
 198        BUG_ON(!irq->hw);
 199        WARN_ON(irq_set_irqchip_state(irq->host_irq,
 200                                      IRQCHIP_STATE_ACTIVE,
 201                                      active));
 202}
 203
 204/**
 205 * kvm_vgic_target_oracle - compute the target vcpu for an irq
 206 *
 207 * @irq:        The irq to route. Must be already locked.
 208 *
 209 * Based on the current state of the interrupt (enabled, pending,
 210 * active, vcpu and target_vcpu), compute the next vcpu this should be
 211 * given to. Return NULL if this shouldn't be injected at all.
 212 *
 213 * Requires the IRQ lock to be held.
 214 */
 215static struct kvm_vcpu *vgic_target_oracle(struct vgic_irq *irq)
 216{
 217        lockdep_assert_held(&irq->irq_lock);
 218
 219        /* If the interrupt is active, it must stay on the current vcpu */
 220        if (irq->active)
 221                return irq->vcpu ? : irq->target_vcpu;
 222
 223        /*
 224         * If the IRQ is not active but enabled and pending, we should direct
 225         * it to its configured target VCPU.
 226         * If the distributor is disabled, pending interrupts shouldn't be
 227         * forwarded.
 228         */
 229        if (irq->enabled && irq_is_pending(irq)) {
 230                if (unlikely(irq->target_vcpu &&
 231                             !irq->target_vcpu->kvm->arch.vgic.enabled))
 232                        return NULL;
 233
 234                return irq->target_vcpu;
 235        }
 236
 237        /* If neither active nor pending and enabled, then this IRQ should not
 238         * be queued to any VCPU.
 239         */
 240        return NULL;
 241}
 242
 243/*
 244 * The order of items in the ap_lists defines how we'll pack things in LRs as
 245 * well, the first items in the list being the first things populated in the
 246 * LRs.
 247 *
 248 * A hard rule is that active interrupts can never be pushed out of the LRs
 249 * (and therefore take priority) since we cannot reliably trap on deactivation
 250 * of IRQs and therefore they have to be present in the LRs.
 251 *
 252 * Otherwise things should be sorted by the priority field and the GIC
 253 * hardware support will take care of preemption of priority groups etc.
 254 *
 255 * Return negative if "a" sorts before "b", 0 to preserve order, and positive
 256 * to sort "b" before "a".
 257 */
 258static int vgic_irq_cmp(void *priv, struct list_head *a, struct list_head *b)
 259{
 260        struct vgic_irq *irqa = container_of(a, struct vgic_irq, ap_list);
 261        struct vgic_irq *irqb = container_of(b, struct vgic_irq, ap_list);
 262        bool penda, pendb;
 263        int ret;
 264
 265        /*
 266         * list_sort may call this function with the same element when
 267         * the list is fairly long.
 268         */
 269        if (unlikely(irqa == irqb))
 270                return 0;
 271
 272        raw_spin_lock(&irqa->irq_lock);
 273        raw_spin_lock_nested(&irqb->irq_lock, SINGLE_DEPTH_NESTING);
 274
 275        if (irqa->active || irqb->active) {
 276                ret = (int)irqb->active - (int)irqa->active;
 277                goto out;
 278        }
 279
 280        penda = irqa->enabled && irq_is_pending(irqa);
 281        pendb = irqb->enabled && irq_is_pending(irqb);
 282
 283        if (!penda || !pendb) {
 284                ret = (int)pendb - (int)penda;
 285                goto out;
 286        }
 287
 288        /* Both pending and enabled, sort by priority */
 289        ret = irqa->priority - irqb->priority;
 290out:
 291        raw_spin_unlock(&irqb->irq_lock);
 292        raw_spin_unlock(&irqa->irq_lock);
 293        return ret;
 294}
 295
 296/* Must be called with the ap_list_lock held */
 297static void vgic_sort_ap_list(struct kvm_vcpu *vcpu)
 298{
 299        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 300
 301        lockdep_assert_held(&vgic_cpu->ap_list_lock);
 302
 303        list_sort(NULL, &vgic_cpu->ap_list_head, vgic_irq_cmp);
 304}
 305
 306/*
 307 * Only valid injection if changing level for level-triggered IRQs or for a
 308 * rising edge, and in-kernel connected IRQ lines can only be controlled by
 309 * their owner.
 310 */
 311static bool vgic_validate_injection(struct vgic_irq *irq, bool level, void *owner)
 312{
 313        if (irq->owner != owner)
 314                return false;
 315
 316        switch (irq->config) {
 317        case VGIC_CONFIG_LEVEL:
 318                return irq->line_level != level;
 319        case VGIC_CONFIG_EDGE:
 320                return level;
 321        }
 322
 323        return false;
 324}
 325
 326/*
 327 * Check whether an IRQ needs to (and can) be queued to a VCPU's ap list.
 328 * Do the queuing if necessary, taking the right locks in the right order.
 329 * Returns true when the IRQ was queued, false otherwise.
 330 *
 331 * Needs to be entered with the IRQ lock already held, but will return
 332 * with all locks dropped.
 333 */
 334bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq,
 335                           unsigned long flags)
 336{
 337        struct kvm_vcpu *vcpu;
 338
 339        lockdep_assert_held(&irq->irq_lock);
 340
 341retry:
 342        vcpu = vgic_target_oracle(irq);
 343        if (irq->vcpu || !vcpu) {
 344                /*
 345                 * If this IRQ is already on a VCPU's ap_list, then it
 346                 * cannot be moved or modified and there is no more work for
 347                 * us to do.
 348                 *
 349                 * Otherwise, if the irq is not pending and enabled, it does
 350                 * not need to be inserted into an ap_list and there is also
 351                 * no more work for us to do.
 352                 */
 353                raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
 354
 355                /*
 356                 * We have to kick the VCPU here, because we could be
 357                 * queueing an edge-triggered interrupt for which we
 358                 * get no EOI maintenance interrupt. In that case,
 359                 * while the IRQ is already on the VCPU's AP list, the
 360                 * VCPU could have EOI'ed the original interrupt and
 361                 * won't see this one until it exits for some other
 362                 * reason.
 363                 */
 364                if (vcpu) {
 365                        kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
 366                        kvm_vcpu_kick(vcpu);
 367                }
 368                return false;
 369        }
 370
 371        /*
 372         * We must unlock the irq lock to take the ap_list_lock where
 373         * we are going to insert this new pending interrupt.
 374         */
 375        raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
 376
 377        /* someone can do stuff here, which we re-check below */
 378
 379        raw_spin_lock_irqsave(&vcpu->arch.vgic_cpu.ap_list_lock, flags);
 380        raw_spin_lock(&irq->irq_lock);
 381
 382        /*
 383         * Did something change behind our backs?
 384         *
 385         * There are two cases:
 386         * 1) The irq lost its pending state or was disabled behind our
 387         *    backs and/or it was queued to another VCPU's ap_list.
 388         * 2) Someone changed the affinity on this irq behind our
 389         *    backs and we are now holding the wrong ap_list_lock.
 390         *
 391         * In both cases, drop the locks and retry.
 392         */
 393
 394        if (unlikely(irq->vcpu || vcpu != vgic_target_oracle(irq))) {
 395                raw_spin_unlock(&irq->irq_lock);
 396                raw_spin_unlock_irqrestore(&vcpu->arch.vgic_cpu.ap_list_lock,
 397                                           flags);
 398
 399                raw_spin_lock_irqsave(&irq->irq_lock, flags);
 400                goto retry;
 401        }
 402
 403        /*
 404         * Grab a reference to the irq to reflect the fact that it is
 405         * now in the ap_list.
 406         */
 407        vgic_get_irq_kref(irq);
 408        list_add_tail(&irq->ap_list, &vcpu->arch.vgic_cpu.ap_list_head);
 409        irq->vcpu = vcpu;
 410
 411        raw_spin_unlock(&irq->irq_lock);
 412        raw_spin_unlock_irqrestore(&vcpu->arch.vgic_cpu.ap_list_lock, flags);
 413
 414        kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
 415        kvm_vcpu_kick(vcpu);
 416
 417        return true;
 418}
 419
 420/**
 421 * kvm_vgic_inject_irq - Inject an IRQ from a device to the vgic
 422 * @kvm:     The VM structure pointer
 423 * @cpuid:   The CPU for PPIs
 424 * @intid:   The INTID to inject a new state to.
 425 * @level:   Edge-triggered:  true:  to trigger the interrupt
 426 *                            false: to ignore the call
 427 *           Level-sensitive  true:  raise the input signal
 428 *                            false: lower the input signal
 429 * @owner:   The opaque pointer to the owner of the IRQ being raised to verify
 430 *           that the caller is allowed to inject this IRQ.  Userspace
 431 *           injections will have owner == NULL.
 432 *
 433 * The VGIC is not concerned with devices being active-LOW or active-HIGH for
 434 * level-sensitive interrupts.  You can think of the level parameter as 1
 435 * being HIGH and 0 being LOW and all devices being active-HIGH.
 436 */
 437int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
 438                        bool level, void *owner)
 439{
 440        struct kvm_vcpu *vcpu;
 441        struct vgic_irq *irq;
 442        unsigned long flags;
 443        int ret;
 444
 445        trace_vgic_update_irq_pending(cpuid, intid, level);
 446
 447        ret = vgic_lazy_init(kvm);
 448        if (ret)
 449                return ret;
 450
 451        vcpu = kvm_get_vcpu(kvm, cpuid);
 452        if (!vcpu && intid < VGIC_NR_PRIVATE_IRQS)
 453                return -EINVAL;
 454
 455        irq = vgic_get_irq(kvm, vcpu, intid);
 456        if (!irq)
 457                return -EINVAL;
 458
 459        raw_spin_lock_irqsave(&irq->irq_lock, flags);
 460
 461        if (!vgic_validate_injection(irq, level, owner)) {
 462                /* Nothing to see here, move along... */
 463                raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
 464                vgic_put_irq(kvm, irq);
 465                return 0;
 466        }
 467
 468        if (irq->config == VGIC_CONFIG_LEVEL)
 469                irq->line_level = level;
 470        else
 471                irq->pending_latch = true;
 472
 473        vgic_queue_irq_unlock(kvm, irq, flags);
 474        vgic_put_irq(kvm, irq);
 475
 476        return 0;
 477}
 478
 479/* @irq->irq_lock must be held */
 480static int kvm_vgic_map_irq(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
 481                            unsigned int host_irq,
 482                            bool (*get_input_level)(int vindid))
 483{
 484        struct irq_desc *desc;
 485        struct irq_data *data;
 486
 487        /*
 488         * Find the physical IRQ number corresponding to @host_irq
 489         */
 490        desc = irq_to_desc(host_irq);
 491        if (!desc) {
 492                kvm_err("%s: no interrupt descriptor\n", __func__);
 493                return -EINVAL;
 494        }
 495        data = irq_desc_get_irq_data(desc);
 496        while (data->parent_data)
 497                data = data->parent_data;
 498
 499        irq->hw = true;
 500        irq->host_irq = host_irq;
 501        irq->hwintid = data->hwirq;
 502        irq->get_input_level = get_input_level;
 503        return 0;
 504}
 505
 506/* @irq->irq_lock must be held */
 507static inline void kvm_vgic_unmap_irq(struct vgic_irq *irq)
 508{
 509        irq->hw = false;
 510        irq->hwintid = 0;
 511        irq->get_input_level = NULL;
 512}
 513
 514int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,
 515                          u32 vintid, bool (*get_input_level)(int vindid))
 516{
 517        struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
 518        unsigned long flags;
 519        int ret;
 520
 521        BUG_ON(!irq);
 522
 523        raw_spin_lock_irqsave(&irq->irq_lock, flags);
 524        ret = kvm_vgic_map_irq(vcpu, irq, host_irq, get_input_level);
 525        raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
 526        vgic_put_irq(vcpu->kvm, irq);
 527
 528        return ret;
 529}
 530
 531/**
 532 * kvm_vgic_reset_mapped_irq - Reset a mapped IRQ
 533 * @vcpu: The VCPU pointer
 534 * @vintid: The INTID of the interrupt
 535 *
 536 * Reset the active and pending states of a mapped interrupt.  Kernel
 537 * subsystems injecting mapped interrupts should reset their interrupt lines
 538 * when we are doing a reset of the VM.
 539 */
 540void kvm_vgic_reset_mapped_irq(struct kvm_vcpu *vcpu, u32 vintid)
 541{
 542        struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
 543        unsigned long flags;
 544
 545        if (!irq->hw)
 546                goto out;
 547
 548        raw_spin_lock_irqsave(&irq->irq_lock, flags);
 549        irq->active = false;
 550        irq->pending_latch = false;
 551        irq->line_level = false;
 552        raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
 553out:
 554        vgic_put_irq(vcpu->kvm, irq);
 555}
 556
 557int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid)
 558{
 559        struct vgic_irq *irq;
 560        unsigned long flags;
 561
 562        if (!vgic_initialized(vcpu->kvm))
 563                return -EAGAIN;
 564
 565        irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
 566        BUG_ON(!irq);
 567
 568        raw_spin_lock_irqsave(&irq->irq_lock, flags);
 569        kvm_vgic_unmap_irq(irq);
 570        raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
 571        vgic_put_irq(vcpu->kvm, irq);
 572
 573        return 0;
 574}
 575
 576/**
 577 * kvm_vgic_set_owner - Set the owner of an interrupt for a VM
 578 *
 579 * @vcpu:   Pointer to the VCPU (used for PPIs)
 580 * @intid:  The virtual INTID identifying the interrupt (PPI or SPI)
 581 * @owner:  Opaque pointer to the owner
 582 *
 583 * Returns 0 if intid is not already used by another in-kernel device and the
 584 * owner is set, otherwise returns an error code.
 585 */
 586int kvm_vgic_set_owner(struct kvm_vcpu *vcpu, unsigned int intid, void *owner)
 587{
 588        struct vgic_irq *irq;
 589        unsigned long flags;
 590        int ret = 0;
 591
 592        if (!vgic_initialized(vcpu->kvm))
 593                return -EAGAIN;
 594
 595        /* SGIs and LPIs cannot be wired up to any device */
 596        if (!irq_is_ppi(intid) && !vgic_valid_spi(vcpu->kvm, intid))
 597                return -EINVAL;
 598
 599        irq = vgic_get_irq(vcpu->kvm, vcpu, intid);
 600        raw_spin_lock_irqsave(&irq->irq_lock, flags);
 601        if (irq->owner && irq->owner != owner)
 602                ret = -EEXIST;
 603        else
 604                irq->owner = owner;
 605        raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
 606
 607        return ret;
 608}
 609
 610/**
 611 * vgic_prune_ap_list - Remove non-relevant interrupts from the list
 612 *
 613 * @vcpu: The VCPU pointer
 614 *
 615 * Go over the list of "interesting" interrupts, and prune those that we
 616 * won't have to consider in the near future.
 617 */
 618static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)
 619{
 620        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 621        struct vgic_irq *irq, *tmp;
 622
 623        DEBUG_SPINLOCK_BUG_ON(!irqs_disabled());
 624
 625retry:
 626        raw_spin_lock(&vgic_cpu->ap_list_lock);
 627
 628        list_for_each_entry_safe(irq, tmp, &vgic_cpu->ap_list_head, ap_list) {
 629                struct kvm_vcpu *target_vcpu, *vcpuA, *vcpuB;
 630                bool target_vcpu_needs_kick = false;
 631
 632                raw_spin_lock(&irq->irq_lock);
 633
 634                BUG_ON(vcpu != irq->vcpu);
 635
 636                target_vcpu = vgic_target_oracle(irq);
 637
 638                if (!target_vcpu) {
 639                        /*
 640                         * We don't need to process this interrupt any
 641                         * further, move it off the list.
 642                         */
 643                        list_del(&irq->ap_list);
 644                        irq->vcpu = NULL;
 645                        raw_spin_unlock(&irq->irq_lock);
 646
 647                        /*
 648                         * This vgic_put_irq call matches the
 649                         * vgic_get_irq_kref in vgic_queue_irq_unlock,
 650                         * where we added the LPI to the ap_list. As
 651                         * we remove the irq from the list, we drop
 652                         * also drop the refcount.
 653                         */
 654                        vgic_put_irq(vcpu->kvm, irq);
 655                        continue;
 656                }
 657
 658                if (target_vcpu == vcpu) {
 659                        /* We're on the right CPU */
 660                        raw_spin_unlock(&irq->irq_lock);
 661                        continue;
 662                }
 663
 664                /* This interrupt looks like it has to be migrated. */
 665
 666                raw_spin_unlock(&irq->irq_lock);
 667                raw_spin_unlock(&vgic_cpu->ap_list_lock);
 668
 669                /*
 670                 * Ensure locking order by always locking the smallest
 671                 * ID first.
 672                 */
 673                if (vcpu->vcpu_id < target_vcpu->vcpu_id) {
 674                        vcpuA = vcpu;
 675                        vcpuB = target_vcpu;
 676                } else {
 677                        vcpuA = target_vcpu;
 678                        vcpuB = vcpu;
 679                }
 680
 681                raw_spin_lock(&vcpuA->arch.vgic_cpu.ap_list_lock);
 682                raw_spin_lock_nested(&vcpuB->arch.vgic_cpu.ap_list_lock,
 683                                      SINGLE_DEPTH_NESTING);
 684                raw_spin_lock(&irq->irq_lock);
 685
 686                /*
 687                 * If the affinity has been preserved, move the
 688                 * interrupt around. Otherwise, it means things have
 689                 * changed while the interrupt was unlocked, and we
 690                 * need to replay this.
 691                 *
 692                 * In all cases, we cannot trust the list not to have
 693                 * changed, so we restart from the beginning.
 694                 */
 695                if (target_vcpu == vgic_target_oracle(irq)) {
 696                        struct vgic_cpu *new_cpu = &target_vcpu->arch.vgic_cpu;
 697
 698                        list_del(&irq->ap_list);
 699                        irq->vcpu = target_vcpu;
 700                        list_add_tail(&irq->ap_list, &new_cpu->ap_list_head);
 701                        target_vcpu_needs_kick = true;
 702                }
 703
 704                raw_spin_unlock(&irq->irq_lock);
 705                raw_spin_unlock(&vcpuB->arch.vgic_cpu.ap_list_lock);
 706                raw_spin_unlock(&vcpuA->arch.vgic_cpu.ap_list_lock);
 707
 708                if (target_vcpu_needs_kick) {
 709                        kvm_make_request(KVM_REQ_IRQ_PENDING, target_vcpu);
 710                        kvm_vcpu_kick(target_vcpu);
 711                }
 712
 713                goto retry;
 714        }
 715
 716        raw_spin_unlock(&vgic_cpu->ap_list_lock);
 717}
 718
 719static inline void vgic_fold_lr_state(struct kvm_vcpu *vcpu)
 720{
 721        if (kvm_vgic_global_state.type == VGIC_V2)
 722                vgic_v2_fold_lr_state(vcpu);
 723        else
 724                vgic_v3_fold_lr_state(vcpu);
 725}
 726
 727/* Requires the irq_lock to be held. */
 728static inline void vgic_populate_lr(struct kvm_vcpu *vcpu,
 729                                    struct vgic_irq *irq, int lr)
 730{
 731        lockdep_assert_held(&irq->irq_lock);
 732
 733        if (kvm_vgic_global_state.type == VGIC_V2)
 734                vgic_v2_populate_lr(vcpu, irq, lr);
 735        else
 736                vgic_v3_populate_lr(vcpu, irq, lr);
 737}
 738
 739static inline void vgic_clear_lr(struct kvm_vcpu *vcpu, int lr)
 740{
 741        if (kvm_vgic_global_state.type == VGIC_V2)
 742                vgic_v2_clear_lr(vcpu, lr);
 743        else
 744                vgic_v3_clear_lr(vcpu, lr);
 745}
 746
 747static inline void vgic_set_underflow(struct kvm_vcpu *vcpu)
 748{
 749        if (kvm_vgic_global_state.type == VGIC_V2)
 750                vgic_v2_set_underflow(vcpu);
 751        else
 752                vgic_v3_set_underflow(vcpu);
 753}
 754
 755/* Requires the ap_list_lock to be held. */
 756static int compute_ap_list_depth(struct kvm_vcpu *vcpu,
 757                                 bool *multi_sgi)
 758{
 759        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 760        struct vgic_irq *irq;
 761        int count = 0;
 762
 763        *multi_sgi = false;
 764
 765        lockdep_assert_held(&vgic_cpu->ap_list_lock);
 766
 767        list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
 768                int w;
 769
 770                raw_spin_lock(&irq->irq_lock);
 771                /* GICv2 SGIs can count for more than one... */
 772                w = vgic_irq_get_lr_count(irq);
 773                raw_spin_unlock(&irq->irq_lock);
 774
 775                count += w;
 776                *multi_sgi |= (w > 1);
 777        }
 778        return count;
 779}
 780
 781/* Requires the VCPU's ap_list_lock to be held. */
 782static void vgic_flush_lr_state(struct kvm_vcpu *vcpu)
 783{
 784        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 785        struct vgic_irq *irq;
 786        int count;
 787        bool multi_sgi;
 788        u8 prio = 0xff;
 789
 790        lockdep_assert_held(&vgic_cpu->ap_list_lock);
 791
 792        count = compute_ap_list_depth(vcpu, &multi_sgi);
 793        if (count > kvm_vgic_global_state.nr_lr || multi_sgi)
 794                vgic_sort_ap_list(vcpu);
 795
 796        count = 0;
 797
 798        list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
 799                raw_spin_lock(&irq->irq_lock);
 800
 801                /*
 802                 * If we have multi-SGIs in the pipeline, we need to
 803                 * guarantee that they are all seen before any IRQ of
 804                 * lower priority. In that case, we need to filter out
 805                 * these interrupts by exiting early. This is easy as
 806                 * the AP list has been sorted already.
 807                 */
 808                if (multi_sgi && irq->priority > prio) {
 809                        _raw_spin_unlock(&irq->irq_lock);
 810                        break;
 811                }
 812
 813                if (likely(vgic_target_oracle(irq) == vcpu)) {
 814                        vgic_populate_lr(vcpu, irq, count++);
 815
 816                        if (irq->source)
 817                                prio = irq->priority;
 818                }
 819
 820                raw_spin_unlock(&irq->irq_lock);
 821
 822                if (count == kvm_vgic_global_state.nr_lr) {
 823                        if (!list_is_last(&irq->ap_list,
 824                                          &vgic_cpu->ap_list_head))
 825                                vgic_set_underflow(vcpu);
 826                        break;
 827                }
 828        }
 829
 830        vcpu->arch.vgic_cpu.used_lrs = count;
 831
 832        /* Nuke remaining LRs */
 833        for ( ; count < kvm_vgic_global_state.nr_lr; count++)
 834                vgic_clear_lr(vcpu, count);
 835}
 836
 837static inline bool can_access_vgic_from_kernel(void)
 838{
 839        /*
 840         * GICv2 can always be accessed from the kernel because it is
 841         * memory-mapped, and VHE systems can access GICv3 EL2 system
 842         * registers.
 843         */
 844        return !static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif) || has_vhe();
 845}
 846
 847static inline void vgic_save_state(struct kvm_vcpu *vcpu)
 848{
 849        if (!static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
 850                vgic_v2_save_state(vcpu);
 851        else
 852                __vgic_v3_save_state(vcpu);
 853}
 854
 855/* Sync back the hardware VGIC state into our emulation after a guest's run. */
 856void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
 857{
 858        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 859
 860        WARN_ON(vgic_v4_sync_hwstate(vcpu));
 861
 862        /* An empty ap_list_head implies used_lrs == 0 */
 863        if (list_empty(&vcpu->arch.vgic_cpu.ap_list_head))
 864                return;
 865
 866        if (can_access_vgic_from_kernel())
 867                vgic_save_state(vcpu);
 868
 869        if (vgic_cpu->used_lrs)
 870                vgic_fold_lr_state(vcpu);
 871        vgic_prune_ap_list(vcpu);
 872}
 873
 874static inline void vgic_restore_state(struct kvm_vcpu *vcpu)
 875{
 876        if (!static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
 877                vgic_v2_restore_state(vcpu);
 878        else
 879                __vgic_v3_restore_state(vcpu);
 880}
 881
 882/* Flush our emulation state into the GIC hardware before entering the guest. */
 883void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
 884{
 885        WARN_ON(vgic_v4_flush_hwstate(vcpu));
 886
 887        /*
 888         * If there are no virtual interrupts active or pending for this
 889         * VCPU, then there is no work to do and we can bail out without
 890         * taking any lock.  There is a potential race with someone injecting
 891         * interrupts to the VCPU, but it is a benign race as the VCPU will
 892         * either observe the new interrupt before or after doing this check,
 893         * and introducing additional synchronization mechanism doesn't change
 894         * this.
 895         *
 896         * Note that we still need to go through the whole thing if anything
 897         * can be directly injected (GICv4).
 898         */
 899        if (list_empty(&vcpu->arch.vgic_cpu.ap_list_head) &&
 900            !vgic_supports_direct_msis(vcpu->kvm))
 901                return;
 902
 903        DEBUG_SPINLOCK_BUG_ON(!irqs_disabled());
 904
 905        if (!list_empty(&vcpu->arch.vgic_cpu.ap_list_head)) {
 906                raw_spin_lock(&vcpu->arch.vgic_cpu.ap_list_lock);
 907                vgic_flush_lr_state(vcpu);
 908                raw_spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock);
 909        }
 910
 911        if (can_access_vgic_from_kernel())
 912                vgic_restore_state(vcpu);
 913}
 914
 915void kvm_vgic_load(struct kvm_vcpu *vcpu)
 916{
 917        if (unlikely(!vgic_initialized(vcpu->kvm)))
 918                return;
 919
 920        if (kvm_vgic_global_state.type == VGIC_V2)
 921                vgic_v2_load(vcpu);
 922        else
 923                vgic_v3_load(vcpu);
 924}
 925
 926void kvm_vgic_put(struct kvm_vcpu *vcpu)
 927{
 928        if (unlikely(!vgic_initialized(vcpu->kvm)))
 929                return;
 930
 931        if (kvm_vgic_global_state.type == VGIC_V2)
 932                vgic_v2_put(vcpu);
 933        else
 934                vgic_v3_put(vcpu);
 935}
 936
 937void kvm_vgic_vmcr_sync(struct kvm_vcpu *vcpu)
 938{
 939        if (unlikely(!irqchip_in_kernel(vcpu->kvm)))
 940                return;
 941
 942        if (kvm_vgic_global_state.type == VGIC_V2)
 943                vgic_v2_vmcr_sync(vcpu);
 944        else
 945                vgic_v3_vmcr_sync(vcpu);
 946}
 947
 948int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu)
 949{
 950        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 951        struct vgic_irq *irq;
 952        bool pending = false;
 953        unsigned long flags;
 954        struct vgic_vmcr vmcr;
 955
 956        if (!vcpu->kvm->arch.vgic.enabled)
 957                return false;
 958
 959        if (vcpu->arch.vgic_cpu.vgic_v3.its_vpe.pending_last)
 960                return true;
 961
 962        vgic_get_vmcr(vcpu, &vmcr);
 963
 964        raw_spin_lock_irqsave(&vgic_cpu->ap_list_lock, flags);
 965
 966        list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
 967                raw_spin_lock(&irq->irq_lock);
 968                pending = irq_is_pending(irq) && irq->enabled &&
 969                          !irq->active &&
 970                          irq->priority < vmcr.pmr;
 971                raw_spin_unlock(&irq->irq_lock);
 972
 973                if (pending)
 974                        break;
 975        }
 976
 977        raw_spin_unlock_irqrestore(&vgic_cpu->ap_list_lock, flags);
 978
 979        return pending;
 980}
 981
 982void vgic_kick_vcpus(struct kvm *kvm)
 983{
 984        struct kvm_vcpu *vcpu;
 985        int c;
 986
 987        /*
 988         * We've injected an interrupt, time to find out who deserves
 989         * a good kick...
 990         */
 991        kvm_for_each_vcpu(c, vcpu, kvm) {
 992                if (kvm_vgic_vcpu_pending_irq(vcpu)) {
 993                        kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
 994                        kvm_vcpu_kick(vcpu);
 995                }
 996        }
 997}
 998
 999bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int vintid)
1000{
1001        struct vgic_irq *irq;
1002        bool map_is_active;
1003        unsigned long flags;
1004
1005        if (!vgic_initialized(vcpu->kvm))
1006                return false;
1007
1008        irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
1009        raw_spin_lock_irqsave(&irq->irq_lock, flags);
1010        map_is_active = irq->hw && irq->active;
1011        raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
1012        vgic_put_irq(vcpu->kvm, irq);
1013
1014        return map_is_active;
1015}
1016