linux/arch/arm64/kvm/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->ops && irq->ops->get_input_level)
 186                return irq->ops->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, const struct list_head *a,
 259                        const struct list_head *b)
 260{
 261        struct vgic_irq *irqa = container_of(a, struct vgic_irq, ap_list);
 262        struct vgic_irq *irqb = container_of(b, struct vgic_irq, ap_list);
 263        bool penda, pendb;
 264        int ret;
 265
 266        /*
 267         * list_sort may call this function with the same element when
 268         * the list is fairly long.
 269         */
 270        if (unlikely(irqa == irqb))
 271                return 0;
 272
 273        raw_spin_lock(&irqa->irq_lock);
 274        raw_spin_lock_nested(&irqb->irq_lock, SINGLE_DEPTH_NESTING);
 275
 276        if (irqa->active || irqb->active) {
 277                ret = (int)irqb->active - (int)irqa->active;
 278                goto out;
 279        }
 280
 281        penda = irqa->enabled && irq_is_pending(irqa);
 282        pendb = irqb->enabled && irq_is_pending(irqb);
 283
 284        if (!penda || !pendb) {
 285                ret = (int)pendb - (int)penda;
 286                goto out;
 287        }
 288
 289        /* Both pending and enabled, sort by priority */
 290        ret = irqa->priority - irqb->priority;
 291out:
 292        raw_spin_unlock(&irqb->irq_lock);
 293        raw_spin_unlock(&irqa->irq_lock);
 294        return ret;
 295}
 296
 297/* Must be called with the ap_list_lock held */
 298static void vgic_sort_ap_list(struct kvm_vcpu *vcpu)
 299{
 300        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 301
 302        lockdep_assert_held(&vgic_cpu->ap_list_lock);
 303
 304        list_sort(NULL, &vgic_cpu->ap_list_head, vgic_irq_cmp);
 305}
 306
 307/*
 308 * Only valid injection if changing level for level-triggered IRQs or for a
 309 * rising edge, and in-kernel connected IRQ lines can only be controlled by
 310 * their owner.
 311 */
 312static bool vgic_validate_injection(struct vgic_irq *irq, bool level, void *owner)
 313{
 314        if (irq->owner != owner)
 315                return false;
 316
 317        switch (irq->config) {
 318        case VGIC_CONFIG_LEVEL:
 319                return irq->line_level != level;
 320        case VGIC_CONFIG_EDGE:
 321                return level;
 322        }
 323
 324        return false;
 325}
 326
 327/*
 328 * Check whether an IRQ needs to (and can) be queued to a VCPU's ap list.
 329 * Do the queuing if necessary, taking the right locks in the right order.
 330 * Returns true when the IRQ was queued, false otherwise.
 331 *
 332 * Needs to be entered with the IRQ lock already held, but will return
 333 * with all locks dropped.
 334 */
 335bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq,
 336                           unsigned long flags)
 337{
 338        struct kvm_vcpu *vcpu;
 339
 340        lockdep_assert_held(&irq->irq_lock);
 341
 342retry:
 343        vcpu = vgic_target_oracle(irq);
 344        if (irq->vcpu || !vcpu) {
 345                /*
 346                 * If this IRQ is already on a VCPU's ap_list, then it
 347                 * cannot be moved or modified and there is no more work for
 348                 * us to do.
 349                 *
 350                 * Otherwise, if the irq is not pending and enabled, it does
 351                 * not need to be inserted into an ap_list and there is also
 352                 * no more work for us to do.
 353                 */
 354                raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
 355
 356                /*
 357                 * We have to kick the VCPU here, because we could be
 358                 * queueing an edge-triggered interrupt for which we
 359                 * get no EOI maintenance interrupt. In that case,
 360                 * while the IRQ is already on the VCPU's AP list, the
 361                 * VCPU could have EOI'ed the original interrupt and
 362                 * won't see this one until it exits for some other
 363                 * reason.
 364                 */
 365                if (vcpu) {
 366                        kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
 367                        kvm_vcpu_kick(vcpu);
 368                }
 369                return false;
 370        }
 371
 372        /*
 373         * We must unlock the irq lock to take the ap_list_lock where
 374         * we are going to insert this new pending interrupt.
 375         */
 376        raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
 377
 378        /* someone can do stuff here, which we re-check below */
 379
 380        raw_spin_lock_irqsave(&vcpu->arch.vgic_cpu.ap_list_lock, flags);
 381        raw_spin_lock(&irq->irq_lock);
 382
 383        /*
 384         * Did something change behind our backs?
 385         *
 386         * There are two cases:
 387         * 1) The irq lost its pending state or was disabled behind our
 388         *    backs and/or it was queued to another VCPU's ap_list.
 389         * 2) Someone changed the affinity on this irq behind our
 390         *    backs and we are now holding the wrong ap_list_lock.
 391         *
 392         * In both cases, drop the locks and retry.
 393         */
 394
 395        if (unlikely(irq->vcpu || vcpu != vgic_target_oracle(irq))) {
 396                raw_spin_unlock(&irq->irq_lock);
 397                raw_spin_unlock_irqrestore(&vcpu->arch.vgic_cpu.ap_list_lock,
 398                                           flags);
 399
 400                raw_spin_lock_irqsave(&irq->irq_lock, flags);
 401                goto retry;
 402        }
 403
 404        /*
 405         * Grab a reference to the irq to reflect the fact that it is
 406         * now in the ap_list.
 407         */
 408        vgic_get_irq_kref(irq);
 409        list_add_tail(&irq->ap_list, &vcpu->arch.vgic_cpu.ap_list_head);
 410        irq->vcpu = vcpu;
 411
 412        raw_spin_unlock(&irq->irq_lock);
 413        raw_spin_unlock_irqrestore(&vcpu->arch.vgic_cpu.ap_list_lock, flags);
 414
 415        kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
 416        kvm_vcpu_kick(vcpu);
 417
 418        return true;
 419}
 420
 421/**
 422 * kvm_vgic_inject_irq - Inject an IRQ from a device to the vgic
 423 * @kvm:     The VM structure pointer
 424 * @cpuid:   The CPU for PPIs
 425 * @intid:   The INTID to inject a new state to.
 426 * @level:   Edge-triggered:  true:  to trigger the interrupt
 427 *                            false: to ignore the call
 428 *           Level-sensitive  true:  raise the input signal
 429 *                            false: lower the input signal
 430 * @owner:   The opaque pointer to the owner of the IRQ being raised to verify
 431 *           that the caller is allowed to inject this IRQ.  Userspace
 432 *           injections will have owner == NULL.
 433 *
 434 * The VGIC is not concerned with devices being active-LOW or active-HIGH for
 435 * level-sensitive interrupts.  You can think of the level parameter as 1
 436 * being HIGH and 0 being LOW and all devices being active-HIGH.
 437 */
 438int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
 439                        bool level, void *owner)
 440{
 441        struct kvm_vcpu *vcpu;
 442        struct vgic_irq *irq;
 443        unsigned long flags;
 444        int ret;
 445
 446        trace_vgic_update_irq_pending(cpuid, intid, level);
 447
 448        ret = vgic_lazy_init(kvm);
 449        if (ret)
 450                return ret;
 451
 452        vcpu = kvm_get_vcpu(kvm, cpuid);
 453        if (!vcpu && intid < VGIC_NR_PRIVATE_IRQS)
 454                return -EINVAL;
 455
 456        irq = vgic_get_irq(kvm, vcpu, intid);
 457        if (!irq)
 458                return -EINVAL;
 459
 460        raw_spin_lock_irqsave(&irq->irq_lock, flags);
 461
 462        if (!vgic_validate_injection(irq, level, owner)) {
 463                /* Nothing to see here, move along... */
 464                raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
 465                vgic_put_irq(kvm, irq);
 466                return 0;
 467        }
 468
 469        if (irq->config == VGIC_CONFIG_LEVEL)
 470                irq->line_level = level;
 471        else
 472                irq->pending_latch = true;
 473
 474        vgic_queue_irq_unlock(kvm, irq, flags);
 475        vgic_put_irq(kvm, irq);
 476
 477        return 0;
 478}
 479
 480/* @irq->irq_lock must be held */
 481static int kvm_vgic_map_irq(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
 482                            unsigned int host_irq,
 483                            struct irq_ops *ops)
 484{
 485        struct irq_desc *desc;
 486        struct irq_data *data;
 487
 488        /*
 489         * Find the physical IRQ number corresponding to @host_irq
 490         */
 491        desc = irq_to_desc(host_irq);
 492        if (!desc) {
 493                kvm_err("%s: no interrupt descriptor\n", __func__);
 494                return -EINVAL;
 495        }
 496        data = irq_desc_get_irq_data(desc);
 497        while (data->parent_data)
 498                data = data->parent_data;
 499
 500        irq->hw = true;
 501        irq->host_irq = host_irq;
 502        irq->hwintid = data->hwirq;
 503        irq->ops = ops;
 504        return 0;
 505}
 506
 507/* @irq->irq_lock must be held */
 508static inline void kvm_vgic_unmap_irq(struct vgic_irq *irq)
 509{
 510        irq->hw = false;
 511        irq->hwintid = 0;
 512        irq->ops = NULL;
 513}
 514
 515int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,
 516                          u32 vintid, struct irq_ops *ops)
 517{
 518        struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
 519        unsigned long flags;
 520        int ret;
 521
 522        BUG_ON(!irq);
 523
 524        raw_spin_lock_irqsave(&irq->irq_lock, flags);
 525        ret = kvm_vgic_map_irq(vcpu, irq, host_irq, ops);
 526        raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
 527        vgic_put_irq(vcpu->kvm, irq);
 528
 529        return ret;
 530}
 531
 532/**
 533 * kvm_vgic_reset_mapped_irq - Reset a mapped IRQ
 534 * @vcpu: The VCPU pointer
 535 * @vintid: The INTID of the interrupt
 536 *
 537 * Reset the active and pending states of a mapped interrupt.  Kernel
 538 * subsystems injecting mapped interrupts should reset their interrupt lines
 539 * when we are doing a reset of the VM.
 540 */
 541void kvm_vgic_reset_mapped_irq(struct kvm_vcpu *vcpu, u32 vintid)
 542{
 543        struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
 544        unsigned long flags;
 545
 546        if (!irq->hw)
 547                goto out;
 548
 549        raw_spin_lock_irqsave(&irq->irq_lock, flags);
 550        irq->active = false;
 551        irq->pending_latch = false;
 552        irq->line_level = false;
 553        raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
 554out:
 555        vgic_put_irq(vcpu->kvm, irq);
 556}
 557
 558int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid)
 559{
 560        struct vgic_irq *irq;
 561        unsigned long flags;
 562
 563        if (!vgic_initialized(vcpu->kvm))
 564                return -EAGAIN;
 565
 566        irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
 567        BUG_ON(!irq);
 568
 569        raw_spin_lock_irqsave(&irq->irq_lock, flags);
 570        kvm_vgic_unmap_irq(irq);
 571        raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
 572        vgic_put_irq(vcpu->kvm, irq);
 573
 574        return 0;
 575}
 576
 577/**
 578 * kvm_vgic_set_owner - Set the owner of an interrupt for a VM
 579 *
 580 * @vcpu:   Pointer to the VCPU (used for PPIs)
 581 * @intid:  The virtual INTID identifying the interrupt (PPI or SPI)
 582 * @owner:  Opaque pointer to the owner
 583 *
 584 * Returns 0 if intid is not already used by another in-kernel device and the
 585 * owner is set, otherwise returns an error code.
 586 */
 587int kvm_vgic_set_owner(struct kvm_vcpu *vcpu, unsigned int intid, void *owner)
 588{
 589        struct vgic_irq *irq;
 590        unsigned long flags;
 591        int ret = 0;
 592
 593        if (!vgic_initialized(vcpu->kvm))
 594                return -EAGAIN;
 595
 596        /* SGIs and LPIs cannot be wired up to any device */
 597        if (!irq_is_ppi(intid) && !vgic_valid_spi(vcpu->kvm, intid))
 598                return -EINVAL;
 599
 600        irq = vgic_get_irq(vcpu->kvm, vcpu, intid);
 601        raw_spin_lock_irqsave(&irq->irq_lock, flags);
 602        if (irq->owner && irq->owner != owner)
 603                ret = -EEXIST;
 604        else
 605                irq->owner = owner;
 606        raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
 607
 608        return ret;
 609}
 610
 611/**
 612 * vgic_prune_ap_list - Remove non-relevant interrupts from the list
 613 *
 614 * @vcpu: The VCPU pointer
 615 *
 616 * Go over the list of "interesting" interrupts, and prune those that we
 617 * won't have to consider in the near future.
 618 */
 619static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)
 620{
 621        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 622        struct vgic_irq *irq, *tmp;
 623
 624        DEBUG_SPINLOCK_BUG_ON(!irqs_disabled());
 625
 626retry:
 627        raw_spin_lock(&vgic_cpu->ap_list_lock);
 628
 629        list_for_each_entry_safe(irq, tmp, &vgic_cpu->ap_list_head, ap_list) {
 630                struct kvm_vcpu *target_vcpu, *vcpuA, *vcpuB;
 631                bool target_vcpu_needs_kick = false;
 632
 633                raw_spin_lock(&irq->irq_lock);
 634
 635                BUG_ON(vcpu != irq->vcpu);
 636
 637                target_vcpu = vgic_target_oracle(irq);
 638
 639                if (!target_vcpu) {
 640                        /*
 641                         * We don't need to process this interrupt any
 642                         * further, move it off the list.
 643                         */
 644                        list_del(&irq->ap_list);
 645                        irq->vcpu = NULL;
 646                        raw_spin_unlock(&irq->irq_lock);
 647
 648                        /*
 649                         * This vgic_put_irq call matches the
 650                         * vgic_get_irq_kref in vgic_queue_irq_unlock,
 651                         * where we added the LPI to the ap_list. As
 652                         * we remove the irq from the list, we drop
 653                         * also drop the refcount.
 654                         */
 655                        vgic_put_irq(vcpu->kvm, irq);
 656                        continue;
 657                }
 658
 659                if (target_vcpu == vcpu) {
 660                        /* We're on the right CPU */
 661                        raw_spin_unlock(&irq->irq_lock);
 662                        continue;
 663                }
 664
 665                /* This interrupt looks like it has to be migrated. */
 666
 667                raw_spin_unlock(&irq->irq_lock);
 668                raw_spin_unlock(&vgic_cpu->ap_list_lock);
 669
 670                /*
 671                 * Ensure locking order by always locking the smallest
 672                 * ID first.
 673                 */
 674                if (vcpu->vcpu_id < target_vcpu->vcpu_id) {
 675                        vcpuA = vcpu;
 676                        vcpuB = target_vcpu;
 677                } else {
 678                        vcpuA = target_vcpu;
 679                        vcpuB = vcpu;
 680                }
 681
 682                raw_spin_lock(&vcpuA->arch.vgic_cpu.ap_list_lock);
 683                raw_spin_lock_nested(&vcpuB->arch.vgic_cpu.ap_list_lock,
 684                                      SINGLE_DEPTH_NESTING);
 685                raw_spin_lock(&irq->irq_lock);
 686
 687                /*
 688                 * If the affinity has been preserved, move the
 689                 * interrupt around. Otherwise, it means things have
 690                 * changed while the interrupt was unlocked, and we
 691                 * need to replay this.
 692                 *
 693                 * In all cases, we cannot trust the list not to have
 694                 * changed, so we restart from the beginning.
 695                 */
 696                if (target_vcpu == vgic_target_oracle(irq)) {
 697                        struct vgic_cpu *new_cpu = &target_vcpu->arch.vgic_cpu;
 698
 699                        list_del(&irq->ap_list);
 700                        irq->vcpu = target_vcpu;
 701                        list_add_tail(&irq->ap_list, &new_cpu->ap_list_head);
 702                        target_vcpu_needs_kick = true;
 703                }
 704
 705                raw_spin_unlock(&irq->irq_lock);
 706                raw_spin_unlock(&vcpuB->arch.vgic_cpu.ap_list_lock);
 707                raw_spin_unlock(&vcpuA->arch.vgic_cpu.ap_list_lock);
 708
 709                if (target_vcpu_needs_kick) {
 710                        kvm_make_request(KVM_REQ_IRQ_PENDING, target_vcpu);
 711                        kvm_vcpu_kick(target_vcpu);
 712                }
 713
 714                goto retry;
 715        }
 716
 717        raw_spin_unlock(&vgic_cpu->ap_list_lock);
 718}
 719
 720static inline void vgic_fold_lr_state(struct kvm_vcpu *vcpu)
 721{
 722        if (kvm_vgic_global_state.type == VGIC_V2)
 723                vgic_v2_fold_lr_state(vcpu);
 724        else
 725                vgic_v3_fold_lr_state(vcpu);
 726}
 727
 728/* Requires the irq_lock to be held. */
 729static inline void vgic_populate_lr(struct kvm_vcpu *vcpu,
 730                                    struct vgic_irq *irq, int lr)
 731{
 732        lockdep_assert_held(&irq->irq_lock);
 733
 734        if (kvm_vgic_global_state.type == VGIC_V2)
 735                vgic_v2_populate_lr(vcpu, irq, lr);
 736        else
 737                vgic_v3_populate_lr(vcpu, irq, lr);
 738}
 739
 740static inline void vgic_clear_lr(struct kvm_vcpu *vcpu, int lr)
 741{
 742        if (kvm_vgic_global_state.type == VGIC_V2)
 743                vgic_v2_clear_lr(vcpu, lr);
 744        else
 745                vgic_v3_clear_lr(vcpu, lr);
 746}
 747
 748static inline void vgic_set_underflow(struct kvm_vcpu *vcpu)
 749{
 750        if (kvm_vgic_global_state.type == VGIC_V2)
 751                vgic_v2_set_underflow(vcpu);
 752        else
 753                vgic_v3_set_underflow(vcpu);
 754}
 755
 756/* Requires the ap_list_lock to be held. */
 757static int compute_ap_list_depth(struct kvm_vcpu *vcpu,
 758                                 bool *multi_sgi)
 759{
 760        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 761        struct vgic_irq *irq;
 762        int count = 0;
 763
 764        *multi_sgi = false;
 765
 766        lockdep_assert_held(&vgic_cpu->ap_list_lock);
 767
 768        list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
 769                int w;
 770
 771                raw_spin_lock(&irq->irq_lock);
 772                /* GICv2 SGIs can count for more than one... */
 773                w = vgic_irq_get_lr_count(irq);
 774                raw_spin_unlock(&irq->irq_lock);
 775
 776                count += w;
 777                *multi_sgi |= (w > 1);
 778        }
 779        return count;
 780}
 781
 782/* Requires the VCPU's ap_list_lock to be held. */
 783static void vgic_flush_lr_state(struct kvm_vcpu *vcpu)
 784{
 785        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 786        struct vgic_irq *irq;
 787        int count;
 788        bool multi_sgi;
 789        u8 prio = 0xff;
 790        int i = 0;
 791
 792        lockdep_assert_held(&vgic_cpu->ap_list_lock);
 793
 794        count = compute_ap_list_depth(vcpu, &multi_sgi);
 795        if (count > kvm_vgic_global_state.nr_lr || multi_sgi)
 796                vgic_sort_ap_list(vcpu);
 797
 798        count = 0;
 799
 800        list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
 801                raw_spin_lock(&irq->irq_lock);
 802
 803                /*
 804                 * If we have multi-SGIs in the pipeline, we need to
 805                 * guarantee that they are all seen before any IRQ of
 806                 * lower priority. In that case, we need to filter out
 807                 * these interrupts by exiting early. This is easy as
 808                 * the AP list has been sorted already.
 809                 */
 810                if (multi_sgi && irq->priority > prio) {
 811                        _raw_spin_unlock(&irq->irq_lock);
 812                        break;
 813                }
 814
 815                if (likely(vgic_target_oracle(irq) == vcpu)) {
 816                        vgic_populate_lr(vcpu, irq, count++);
 817
 818                        if (irq->source)
 819                                prio = irq->priority;
 820                }
 821
 822                raw_spin_unlock(&irq->irq_lock);
 823
 824                if (count == kvm_vgic_global_state.nr_lr) {
 825                        if (!list_is_last(&irq->ap_list,
 826                                          &vgic_cpu->ap_list_head))
 827                                vgic_set_underflow(vcpu);
 828                        break;
 829                }
 830        }
 831
 832        /* Nuke remaining LRs */
 833        for (i = count ; i < kvm_vgic_global_state.nr_lr; i++)
 834                vgic_clear_lr(vcpu, i);
 835
 836        if (!static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
 837                vcpu->arch.vgic_cpu.vgic_v2.used_lrs = count;
 838        else
 839                vcpu->arch.vgic_cpu.vgic_v3.used_lrs = count;
 840}
 841
 842static inline bool can_access_vgic_from_kernel(void)
 843{
 844        /*
 845         * GICv2 can always be accessed from the kernel because it is
 846         * memory-mapped, and VHE systems can access GICv3 EL2 system
 847         * registers.
 848         */
 849        return !static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif) || has_vhe();
 850}
 851
 852static inline void vgic_save_state(struct kvm_vcpu *vcpu)
 853{
 854        if (!static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
 855                vgic_v2_save_state(vcpu);
 856        else
 857                __vgic_v3_save_state(&vcpu->arch.vgic_cpu.vgic_v3);
 858}
 859
 860/* Sync back the hardware VGIC state into our emulation after a guest's run. */
 861void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
 862{
 863        int used_lrs;
 864
 865        /* An empty ap_list_head implies used_lrs == 0 */
 866        if (list_empty(&vcpu->arch.vgic_cpu.ap_list_head))
 867                return;
 868
 869        if (can_access_vgic_from_kernel())
 870                vgic_save_state(vcpu);
 871
 872        if (!static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
 873                used_lrs = vcpu->arch.vgic_cpu.vgic_v2.used_lrs;
 874        else
 875                used_lrs = vcpu->arch.vgic_cpu.vgic_v3.used_lrs;
 876
 877        if (used_lrs)
 878                vgic_fold_lr_state(vcpu);
 879        vgic_prune_ap_list(vcpu);
 880}
 881
 882static inline void vgic_restore_state(struct kvm_vcpu *vcpu)
 883{
 884        if (!static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
 885                vgic_v2_restore_state(vcpu);
 886        else
 887                __vgic_v3_restore_state(&vcpu->arch.vgic_cpu.vgic_v3);
 888}
 889
 890/* Flush our emulation state into the GIC hardware before entering the guest. */
 891void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
 892{
 893        /*
 894         * If there are no virtual interrupts active or pending for this
 895         * VCPU, then there is no work to do and we can bail out without
 896         * taking any lock.  There is a potential race with someone injecting
 897         * interrupts to the VCPU, but it is a benign race as the VCPU will
 898         * either observe the new interrupt before or after doing this check,
 899         * and introducing additional synchronization mechanism doesn't change
 900         * this.
 901         *
 902         * Note that we still need to go through the whole thing if anything
 903         * can be directly injected (GICv4).
 904         */
 905        if (list_empty(&vcpu->arch.vgic_cpu.ap_list_head) &&
 906            !vgic_supports_direct_msis(vcpu->kvm))
 907                return;
 908
 909        DEBUG_SPINLOCK_BUG_ON(!irqs_disabled());
 910
 911        if (!list_empty(&vcpu->arch.vgic_cpu.ap_list_head)) {
 912                raw_spin_lock(&vcpu->arch.vgic_cpu.ap_list_lock);
 913                vgic_flush_lr_state(vcpu);
 914                raw_spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock);
 915        }
 916
 917        if (can_access_vgic_from_kernel())
 918                vgic_restore_state(vcpu);
 919
 920        if (vgic_supports_direct_msis(vcpu->kvm))
 921                vgic_v4_commit(vcpu);
 922}
 923
 924void kvm_vgic_load(struct kvm_vcpu *vcpu)
 925{
 926        if (unlikely(!vgic_initialized(vcpu->kvm)))
 927                return;
 928
 929        if (kvm_vgic_global_state.type == VGIC_V2)
 930                vgic_v2_load(vcpu);
 931        else
 932                vgic_v3_load(vcpu);
 933}
 934
 935void kvm_vgic_put(struct kvm_vcpu *vcpu)
 936{
 937        if (unlikely(!vgic_initialized(vcpu->kvm)))
 938                return;
 939
 940        if (kvm_vgic_global_state.type == VGIC_V2)
 941                vgic_v2_put(vcpu);
 942        else
 943                vgic_v3_put(vcpu);
 944}
 945
 946void kvm_vgic_vmcr_sync(struct kvm_vcpu *vcpu)
 947{
 948        if (unlikely(!irqchip_in_kernel(vcpu->kvm)))
 949                return;
 950
 951        if (kvm_vgic_global_state.type == VGIC_V2)
 952                vgic_v2_vmcr_sync(vcpu);
 953        else
 954                vgic_v3_vmcr_sync(vcpu);
 955}
 956
 957int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu)
 958{
 959        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 960        struct vgic_irq *irq;
 961        bool pending = false;
 962        unsigned long flags;
 963        struct vgic_vmcr vmcr;
 964
 965        if (!vcpu->kvm->arch.vgic.enabled)
 966                return false;
 967
 968        if (vcpu->arch.vgic_cpu.vgic_v3.its_vpe.pending_last)
 969                return true;
 970
 971        vgic_get_vmcr(vcpu, &vmcr);
 972
 973        raw_spin_lock_irqsave(&vgic_cpu->ap_list_lock, flags);
 974
 975        list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list) {
 976                raw_spin_lock(&irq->irq_lock);
 977                pending = irq_is_pending(irq) && irq->enabled &&
 978                          !irq->active &&
 979                          irq->priority < vmcr.pmr;
 980                raw_spin_unlock(&irq->irq_lock);
 981
 982                if (pending)
 983                        break;
 984        }
 985
 986        raw_spin_unlock_irqrestore(&vgic_cpu->ap_list_lock, flags);
 987
 988        return pending;
 989}
 990
 991void vgic_kick_vcpus(struct kvm *kvm)
 992{
 993        struct kvm_vcpu *vcpu;
 994        int c;
 995
 996        /*
 997         * We've injected an interrupt, time to find out who deserves
 998         * a good kick...
 999         */
1000        kvm_for_each_vcpu(c, vcpu, kvm) {
1001                if (kvm_vgic_vcpu_pending_irq(vcpu)) {
1002                        kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
1003                        kvm_vcpu_kick(vcpu);
1004                }
1005        }
1006}
1007
1008bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int vintid)
1009{
1010        struct vgic_irq *irq;
1011        bool map_is_active;
1012        unsigned long flags;
1013
1014        if (!vgic_initialized(vcpu->kvm))
1015                return false;
1016
1017        irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
1018        raw_spin_lock_irqsave(&irq->irq_lock, flags);
1019        map_is_active = irq->hw && irq->active;
1020        raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
1021        vgic_put_irq(vcpu->kvm, irq);
1022
1023        return map_is_active;
1024}
1025