linux/arch/arm64/kvm/vgic/vgic-init.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/uaccess.h>
   7#include <linux/interrupt.h>
   8#include <linux/cpu.h>
   9#include <linux/kvm_host.h>
  10#include <kvm/arm_vgic.h>
  11#include <asm/kvm_emulate.h>
  12#include <asm/kvm_mmu.h>
  13#include "vgic.h"
  14
  15/*
  16 * Initialization rules: there are multiple stages to the vgic
  17 * initialization, both for the distributor and the CPU interfaces.  The basic
  18 * idea is that even though the VGIC is not functional or not requested from
  19 * user space, the critical path of the run loop can still call VGIC functions
  20 * that just won't do anything, without them having to check additional
  21 * initialization flags to ensure they don't look at uninitialized data
  22 * structures.
  23 *
  24 * Distributor:
  25 *
  26 * - kvm_vgic_early_init(): initialization of static data that doesn't
  27 *   depend on any sizing information or emulation type. No allocation
  28 *   is allowed there.
  29 *
  30 * - vgic_init(): allocation and initialization of the generic data
  31 *   structures that depend on sizing information (number of CPUs,
  32 *   number of interrupts). Also initializes the vcpu specific data
  33 *   structures. Can be executed lazily for GICv2.
  34 *
  35 * CPU Interface:
  36 *
  37 * - kvm_vgic_vcpu_init(): initialization of static data that
  38 *   doesn't depend on any sizing information or emulation type. No
  39 *   allocation is allowed there.
  40 */
  41
  42/* EARLY INIT */
  43
  44/**
  45 * kvm_vgic_early_init() - Initialize static VGIC VCPU data structures
  46 * @kvm: The VM whose VGIC districutor should be initialized
  47 *
  48 * Only do initialization of static structures that don't require any
  49 * allocation or sizing information from userspace.  vgic_init() called
  50 * kvm_vgic_dist_init() which takes care of the rest.
  51 */
  52void kvm_vgic_early_init(struct kvm *kvm)
  53{
  54        struct vgic_dist *dist = &kvm->arch.vgic;
  55
  56        INIT_LIST_HEAD(&dist->lpi_list_head);
  57        INIT_LIST_HEAD(&dist->lpi_translation_cache);
  58        raw_spin_lock_init(&dist->lpi_list_lock);
  59}
  60
  61/* CREATION */
  62
  63/**
  64 * kvm_vgic_create: triggered by the instantiation of the VGIC device by
  65 * user space, either through the legacy KVM_CREATE_IRQCHIP ioctl (v2 only)
  66 * or through the generic KVM_CREATE_DEVICE API ioctl.
  67 * irqchip_in_kernel() tells you if this function succeeded or not.
  68 * @kvm: kvm struct pointer
  69 * @type: KVM_DEV_TYPE_ARM_VGIC_V[23]
  70 */
  71int kvm_vgic_create(struct kvm *kvm, u32 type)
  72{
  73        int i, ret;
  74        struct kvm_vcpu *vcpu;
  75
  76        if (irqchip_in_kernel(kvm))
  77                return -EEXIST;
  78
  79        /*
  80         * This function is also called by the KVM_CREATE_IRQCHIP handler,
  81         * which had no chance yet to check the availability of the GICv2
  82         * emulation. So check this here again. KVM_CREATE_DEVICE does
  83         * the proper checks already.
  84         */
  85        if (type == KVM_DEV_TYPE_ARM_VGIC_V2 &&
  86                !kvm_vgic_global_state.can_emulate_gicv2)
  87                return -ENODEV;
  88
  89        ret = -EBUSY;
  90        if (!lock_all_vcpus(kvm))
  91                return ret;
  92
  93        kvm_for_each_vcpu(i, vcpu, kvm) {
  94                if (vcpu->arch.has_run_once)
  95                        goto out_unlock;
  96        }
  97        ret = 0;
  98
  99        if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
 100                kvm->arch.max_vcpus = VGIC_V2_MAX_CPUS;
 101        else
 102                kvm->arch.max_vcpus = VGIC_V3_MAX_CPUS;
 103
 104        if (atomic_read(&kvm->online_vcpus) > kvm->arch.max_vcpus) {
 105                ret = -E2BIG;
 106                goto out_unlock;
 107        }
 108
 109        kvm->arch.vgic.in_kernel = true;
 110        kvm->arch.vgic.vgic_model = type;
 111
 112        kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
 113
 114        if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
 115                kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
 116        else
 117                INIT_LIST_HEAD(&kvm->arch.vgic.rd_regions);
 118
 119out_unlock:
 120        unlock_all_vcpus(kvm);
 121        return ret;
 122}
 123
 124/* INIT/DESTROY */
 125
 126/**
 127 * kvm_vgic_dist_init: initialize the dist data structures
 128 * @kvm: kvm struct pointer
 129 * @nr_spis: number of spis, frozen by caller
 130 */
 131static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
 132{
 133        struct vgic_dist *dist = &kvm->arch.vgic;
 134        struct kvm_vcpu *vcpu0 = kvm_get_vcpu(kvm, 0);
 135        int i;
 136
 137        dist->spis = kcalloc(nr_spis, sizeof(struct vgic_irq), GFP_KERNEL);
 138        if (!dist->spis)
 139                return  -ENOMEM;
 140
 141        /*
 142         * In the following code we do not take the irq struct lock since
 143         * no other action on irq structs can happen while the VGIC is
 144         * not initialized yet:
 145         * If someone wants to inject an interrupt or does a MMIO access, we
 146         * require prior initialization in case of a virtual GICv3 or trigger
 147         * initialization when using a virtual GICv2.
 148         */
 149        for (i = 0; i < nr_spis; i++) {
 150                struct vgic_irq *irq = &dist->spis[i];
 151
 152                irq->intid = i + VGIC_NR_PRIVATE_IRQS;
 153                INIT_LIST_HEAD(&irq->ap_list);
 154                raw_spin_lock_init(&irq->irq_lock);
 155                irq->vcpu = NULL;
 156                irq->target_vcpu = vcpu0;
 157                kref_init(&irq->refcount);
 158                switch (dist->vgic_model) {
 159                case KVM_DEV_TYPE_ARM_VGIC_V2:
 160                        irq->targets = 0;
 161                        irq->group = 0;
 162                        break;
 163                case KVM_DEV_TYPE_ARM_VGIC_V3:
 164                        irq->mpidr = 0;
 165                        irq->group = 1;
 166                        break;
 167                default:
 168                        kfree(dist->spis);
 169                        dist->spis = NULL;
 170                        return -EINVAL;
 171                }
 172        }
 173        return 0;
 174}
 175
 176/**
 177 * kvm_vgic_vcpu_init() - Initialize static VGIC VCPU data
 178 * structures and register VCPU-specific KVM iodevs
 179 *
 180 * @vcpu: pointer to the VCPU being created and initialized
 181 *
 182 * Only do initialization, but do not actually enable the
 183 * VGIC CPU interface
 184 */
 185int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
 186{
 187        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 188        struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
 189        int ret = 0;
 190        int i;
 191
 192        vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF;
 193
 194        INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
 195        raw_spin_lock_init(&vgic_cpu->ap_list_lock);
 196        atomic_set(&vgic_cpu->vgic_v3.its_vpe.vlpi_count, 0);
 197
 198        /*
 199         * Enable and configure all SGIs to be edge-triggered and
 200         * configure all PPIs as level-triggered.
 201         */
 202        for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
 203                struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
 204
 205                INIT_LIST_HEAD(&irq->ap_list);
 206                raw_spin_lock_init(&irq->irq_lock);
 207                irq->intid = i;
 208                irq->vcpu = NULL;
 209                irq->target_vcpu = vcpu;
 210                kref_init(&irq->refcount);
 211                if (vgic_irq_is_sgi(i)) {
 212                        /* SGIs */
 213                        irq->enabled = 1;
 214                        irq->config = VGIC_CONFIG_EDGE;
 215                } else {
 216                        /* PPIs */
 217                        irq->config = VGIC_CONFIG_LEVEL;
 218                }
 219        }
 220
 221        if (!irqchip_in_kernel(vcpu->kvm))
 222                return 0;
 223
 224        /*
 225         * If we are creating a VCPU with a GICv3 we must also register the
 226         * KVM io device for the redistributor that belongs to this VCPU.
 227         */
 228        if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
 229                mutex_lock(&vcpu->kvm->lock);
 230                ret = vgic_register_redist_iodev(vcpu);
 231                mutex_unlock(&vcpu->kvm->lock);
 232        }
 233        return ret;
 234}
 235
 236static void kvm_vgic_vcpu_enable(struct kvm_vcpu *vcpu)
 237{
 238        if (kvm_vgic_global_state.type == VGIC_V2)
 239                vgic_v2_enable(vcpu);
 240        else
 241                vgic_v3_enable(vcpu);
 242}
 243
 244/*
 245 * vgic_init: allocates and initializes dist and vcpu data structures
 246 * depending on two dimensioning parameters:
 247 * - the number of spis
 248 * - the number of vcpus
 249 * The function is generally called when nr_spis has been explicitly set
 250 * by the guest through the KVM DEVICE API. If not nr_spis is set to 256.
 251 * vgic_initialized() returns true when this function has succeeded.
 252 * Must be called with kvm->lock held!
 253 */
 254int vgic_init(struct kvm *kvm)
 255{
 256        struct vgic_dist *dist = &kvm->arch.vgic;
 257        struct kvm_vcpu *vcpu;
 258        int ret = 0, i, idx;
 259
 260        if (vgic_initialized(kvm))
 261                return 0;
 262
 263        /* Are we also in the middle of creating a VCPU? */
 264        if (kvm->created_vcpus != atomic_read(&kvm->online_vcpus))
 265                return -EBUSY;
 266
 267        /* freeze the number of spis */
 268        if (!dist->nr_spis)
 269                dist->nr_spis = VGIC_NR_IRQS_LEGACY - VGIC_NR_PRIVATE_IRQS;
 270
 271        ret = kvm_vgic_dist_init(kvm, dist->nr_spis);
 272        if (ret)
 273                goto out;
 274
 275        /* Initialize groups on CPUs created before the VGIC type was known */
 276        kvm_for_each_vcpu(idx, vcpu, kvm) {
 277                struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 278
 279                for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
 280                        struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
 281                        switch (dist->vgic_model) {
 282                        case KVM_DEV_TYPE_ARM_VGIC_V3:
 283                                irq->group = 1;
 284                                irq->mpidr = kvm_vcpu_get_mpidr_aff(vcpu);
 285                                break;
 286                        case KVM_DEV_TYPE_ARM_VGIC_V2:
 287                                irq->group = 0;
 288                                irq->targets = 1U << idx;
 289                                break;
 290                        default:
 291                                ret = -EINVAL;
 292                                goto out;
 293                        }
 294                }
 295        }
 296
 297        if (vgic_has_its(kvm))
 298                vgic_lpi_translation_cache_init(kvm);
 299
 300        /*
 301         * If we have GICv4.1 enabled, unconditionnaly request enable the
 302         * v4 support so that we get HW-accelerated vSGIs. Otherwise, only
 303         * enable it if we present a virtual ITS to the guest.
 304         */
 305        if (vgic_supports_direct_msis(kvm)) {
 306                ret = vgic_v4_init(kvm);
 307                if (ret)
 308                        goto out;
 309        }
 310
 311        kvm_for_each_vcpu(i, vcpu, kvm)
 312                kvm_vgic_vcpu_enable(vcpu);
 313
 314        ret = kvm_vgic_setup_default_irq_routing(kvm);
 315        if (ret)
 316                goto out;
 317
 318        vgic_debug_init(kvm);
 319
 320        dist->implementation_rev = 2;
 321        dist->initialized = true;
 322
 323out:
 324        return ret;
 325}
 326
 327static void kvm_vgic_dist_destroy(struct kvm *kvm)
 328{
 329        struct vgic_dist *dist = &kvm->arch.vgic;
 330        struct vgic_redist_region *rdreg, *next;
 331
 332        dist->ready = false;
 333        dist->initialized = false;
 334
 335        kfree(dist->spis);
 336        dist->spis = NULL;
 337        dist->nr_spis = 0;
 338        dist->vgic_dist_base = VGIC_ADDR_UNDEF;
 339
 340        if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
 341                list_for_each_entry_safe(rdreg, next, &dist->rd_regions, list)
 342                        vgic_v3_free_redist_region(rdreg);
 343                INIT_LIST_HEAD(&dist->rd_regions);
 344        } else {
 345                dist->vgic_cpu_base = VGIC_ADDR_UNDEF;
 346        }
 347
 348        if (vgic_has_its(kvm))
 349                vgic_lpi_translation_cache_destroy(kvm);
 350
 351        if (vgic_supports_direct_msis(kvm))
 352                vgic_v4_teardown(kvm);
 353}
 354
 355void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
 356{
 357        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 358
 359        /*
 360         * Retire all pending LPIs on this vcpu anyway as we're
 361         * going to destroy it.
 362         */
 363        vgic_flush_pending_lpis(vcpu);
 364
 365        INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
 366        vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF;
 367}
 368
 369/* To be called with kvm->lock held */
 370static void __kvm_vgic_destroy(struct kvm *kvm)
 371{
 372        struct kvm_vcpu *vcpu;
 373        int i;
 374
 375        vgic_debug_destroy(kvm);
 376
 377        kvm_for_each_vcpu(i, vcpu, kvm)
 378                kvm_vgic_vcpu_destroy(vcpu);
 379
 380        kvm_vgic_dist_destroy(kvm);
 381}
 382
 383void kvm_vgic_destroy(struct kvm *kvm)
 384{
 385        mutex_lock(&kvm->lock);
 386        __kvm_vgic_destroy(kvm);
 387        mutex_unlock(&kvm->lock);
 388}
 389
 390/**
 391 * vgic_lazy_init: Lazy init is only allowed if the GIC exposed to the guest
 392 * is a GICv2. A GICv3 must be explicitly initialized by the guest using the
 393 * KVM_DEV_ARM_VGIC_GRP_CTRL KVM_DEVICE group.
 394 * @kvm: kvm struct pointer
 395 */
 396int vgic_lazy_init(struct kvm *kvm)
 397{
 398        int ret = 0;
 399
 400        if (unlikely(!vgic_initialized(kvm))) {
 401                /*
 402                 * We only provide the automatic initialization of the VGIC
 403                 * for the legacy case of a GICv2. Any other type must
 404                 * be explicitly initialized once setup with the respective
 405                 * KVM device call.
 406                 */
 407                if (kvm->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V2)
 408                        return -EBUSY;
 409
 410                mutex_lock(&kvm->lock);
 411                ret = vgic_init(kvm);
 412                mutex_unlock(&kvm->lock);
 413        }
 414
 415        return ret;
 416}
 417
 418/* RESOURCE MAPPING */
 419
 420/**
 421 * Map the MMIO regions depending on the VGIC model exposed to the guest
 422 * called on the first VCPU run.
 423 * Also map the virtual CPU interface into the VM.
 424 * v2 calls vgic_init() if not already done.
 425 * v3 and derivatives return an error if the VGIC is not initialized.
 426 * vgic_ready() returns true if this function has succeeded.
 427 * @kvm: kvm struct pointer
 428 */
 429int kvm_vgic_map_resources(struct kvm *kvm)
 430{
 431        struct vgic_dist *dist = &kvm->arch.vgic;
 432        int ret = 0;
 433
 434        if (likely(vgic_ready(kvm)))
 435                return 0;
 436
 437        mutex_lock(&kvm->lock);
 438        if (vgic_ready(kvm))
 439                goto out;
 440
 441        if (!irqchip_in_kernel(kvm))
 442                goto out;
 443
 444        if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
 445                ret = vgic_v2_map_resources(kvm);
 446        else
 447                ret = vgic_v3_map_resources(kvm);
 448
 449        if (ret)
 450                __kvm_vgic_destroy(kvm);
 451        else
 452                dist->ready = true;
 453
 454out:
 455        mutex_unlock(&kvm->lock);
 456        return ret;
 457}
 458
 459/* GENERIC PROBE */
 460
 461static int vgic_init_cpu_starting(unsigned int cpu)
 462{
 463        enable_percpu_irq(kvm_vgic_global_state.maint_irq, 0);
 464        return 0;
 465}
 466
 467
 468static int vgic_init_cpu_dying(unsigned int cpu)
 469{
 470        disable_percpu_irq(kvm_vgic_global_state.maint_irq);
 471        return 0;
 472}
 473
 474static irqreturn_t vgic_maintenance_handler(int irq, void *data)
 475{
 476        /*
 477         * We cannot rely on the vgic maintenance interrupt to be
 478         * delivered synchronously. This means we can only use it to
 479         * exit the VM, and we perform the handling of EOIed
 480         * interrupts on the exit path (see vgic_fold_lr_state).
 481         */
 482        return IRQ_HANDLED;
 483}
 484
 485static struct gic_kvm_info *gic_kvm_info;
 486
 487void __init vgic_set_kvm_info(const struct gic_kvm_info *info)
 488{
 489        BUG_ON(gic_kvm_info != NULL);
 490        gic_kvm_info = kmalloc(sizeof(*info), GFP_KERNEL);
 491        if (gic_kvm_info)
 492                *gic_kvm_info = *info;
 493}
 494
 495/**
 496 * kvm_vgic_init_cpu_hardware - initialize the GIC VE hardware
 497 *
 498 * For a specific CPU, initialize the GIC VE hardware.
 499 */
 500void kvm_vgic_init_cpu_hardware(void)
 501{
 502        BUG_ON(preemptible());
 503
 504        /*
 505         * We want to make sure the list registers start out clear so that we
 506         * only have the program the used registers.
 507         */
 508        if (kvm_vgic_global_state.type == VGIC_V2)
 509                vgic_v2_init_lrs();
 510        else
 511                kvm_call_hyp(__vgic_v3_init_lrs);
 512}
 513
 514/**
 515 * kvm_vgic_hyp_init: populates the kvm_vgic_global_state variable
 516 * according to the host GIC model. Accordingly calls either
 517 * vgic_v2/v3_probe which registers the KVM_DEVICE that can be
 518 * instantiated by a guest later on .
 519 */
 520int kvm_vgic_hyp_init(void)
 521{
 522        bool has_mask;
 523        int ret;
 524
 525        if (!gic_kvm_info)
 526                return -ENODEV;
 527
 528        has_mask = !gic_kvm_info->no_maint_irq_mask;
 529
 530        if (has_mask && !gic_kvm_info->maint_irq) {
 531                kvm_err("No vgic maintenance irq\n");
 532                return -ENXIO;
 533        }
 534
 535        /*
 536         * If we get one of these oddball non-GICs, taint the kernel,
 537         * as we have no idea of how they *really* behave.
 538         */
 539        if (gic_kvm_info->no_hw_deactivation) {
 540                kvm_info("Non-architectural vgic, tainting kernel\n");
 541                add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
 542                kvm_vgic_global_state.no_hw_deactivation = true;
 543        }
 544
 545        switch (gic_kvm_info->type) {
 546        case GIC_V2:
 547                ret = vgic_v2_probe(gic_kvm_info);
 548                break;
 549        case GIC_V3:
 550                ret = vgic_v3_probe(gic_kvm_info);
 551                if (!ret) {
 552                        static_branch_enable(&kvm_vgic_global_state.gicv3_cpuif);
 553                        kvm_info("GIC system register CPU interface enabled\n");
 554                }
 555                break;
 556        default:
 557                ret = -ENODEV;
 558        }
 559
 560        kvm_vgic_global_state.maint_irq = gic_kvm_info->maint_irq;
 561
 562        kfree(gic_kvm_info);
 563        gic_kvm_info = NULL;
 564
 565        if (ret)
 566                return ret;
 567
 568        if (!has_mask)
 569                return 0;
 570
 571        ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,
 572                                 vgic_maintenance_handler,
 573                                 "vgic", kvm_get_running_vcpus());
 574        if (ret) {
 575                kvm_err("Cannot register interrupt %d\n",
 576                        kvm_vgic_global_state.maint_irq);
 577                return ret;
 578        }
 579
 580        ret = cpuhp_setup_state(CPUHP_AP_KVM_ARM_VGIC_INIT_STARTING,
 581                                "kvm/arm/vgic:starting",
 582                                vgic_init_cpu_starting, vgic_init_cpu_dying);
 583        if (ret) {
 584                kvm_err("Cannot register vgic CPU notifier\n");
 585                goto out_free_irq;
 586        }
 587
 588        kvm_info("vgic interrupt IRQ%d\n", kvm_vgic_global_state.maint_irq);
 589        return 0;
 590
 591out_free_irq:
 592        free_percpu_irq(kvm_vgic_global_state.maint_irq,
 593                        kvm_get_running_vcpus());
 594        return ret;
 595}
 596
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