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
 339        if (kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
 340                list_for_each_entry_safe(rdreg, next, &dist->rd_regions, list) {
 341                        list_del(&rdreg->list);
 342                        kfree(rdreg);
 343                }
 344                INIT_LIST_HEAD(&dist->rd_regions);
 345        }
 346
 347        if (vgic_has_its(kvm))
 348                vgic_lpi_translation_cache_destroy(kvm);
 349
 350        if (vgic_supports_direct_msis(kvm))
 351                vgic_v4_teardown(kvm);
 352}
 353
 354void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
 355{
 356        struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 357
 358        /*
 359         * Retire all pending LPIs on this vcpu anyway as we're
 360         * going to destroy it.
 361         */
 362        vgic_flush_pending_lpis(vcpu);
 363
 364        INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
 365}
 366
 367/* To be called with kvm->lock held */
 368static void __kvm_vgic_destroy(struct kvm *kvm)
 369{
 370        struct kvm_vcpu *vcpu;
 371        int i;
 372
 373        vgic_debug_destroy(kvm);
 374
 375        kvm_for_each_vcpu(i, vcpu, kvm)
 376                kvm_vgic_vcpu_destroy(vcpu);
 377
 378        kvm_vgic_dist_destroy(kvm);
 379}
 380
 381void kvm_vgic_destroy(struct kvm *kvm)
 382{
 383        mutex_lock(&kvm->lock);
 384        __kvm_vgic_destroy(kvm);
 385        mutex_unlock(&kvm->lock);
 386}
 387
 388/**
 389 * vgic_lazy_init: Lazy init is only allowed if the GIC exposed to the guest
 390 * is a GICv2. A GICv3 must be explicitly initialized by the guest using the
 391 * KVM_DEV_ARM_VGIC_GRP_CTRL KVM_DEVICE group.
 392 * @kvm: kvm struct pointer
 393 */
 394int vgic_lazy_init(struct kvm *kvm)
 395{
 396        int ret = 0;
 397
 398        if (unlikely(!vgic_initialized(kvm))) {
 399                /*
 400                 * We only provide the automatic initialization of the VGIC
 401                 * for the legacy case of a GICv2. Any other type must
 402                 * be explicitly initialized once setup with the respective
 403                 * KVM device call.
 404                 */
 405                if (kvm->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V2)
 406                        return -EBUSY;
 407
 408                mutex_lock(&kvm->lock);
 409                ret = vgic_init(kvm);
 410                mutex_unlock(&kvm->lock);
 411        }
 412
 413        return ret;
 414}
 415
 416/* RESOURCE MAPPING */
 417
 418/**
 419 * Map the MMIO regions depending on the VGIC model exposed to the guest
 420 * called on the first VCPU run.
 421 * Also map the virtual CPU interface into the VM.
 422 * v2/v3 derivatives call vgic_init if not already done.
 423 * vgic_ready() returns true if this function has succeeded.
 424 * @kvm: kvm struct pointer
 425 */
 426int kvm_vgic_map_resources(struct kvm *kvm)
 427{
 428        struct vgic_dist *dist = &kvm->arch.vgic;
 429        int ret = 0;
 430
 431        mutex_lock(&kvm->lock);
 432        if (!irqchip_in_kernel(kvm))
 433                goto out;
 434
 435        if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
 436                ret = vgic_v2_map_resources(kvm);
 437        else
 438                ret = vgic_v3_map_resources(kvm);
 439
 440        if (ret)
 441                __kvm_vgic_destroy(kvm);
 442
 443out:
 444        mutex_unlock(&kvm->lock);
 445        return ret;
 446}
 447
 448/* GENERIC PROBE */
 449
 450static int vgic_init_cpu_starting(unsigned int cpu)
 451{
 452        enable_percpu_irq(kvm_vgic_global_state.maint_irq, 0);
 453        return 0;
 454}
 455
 456
 457static int vgic_init_cpu_dying(unsigned int cpu)
 458{
 459        disable_percpu_irq(kvm_vgic_global_state.maint_irq);
 460        return 0;
 461}
 462
 463static irqreturn_t vgic_maintenance_handler(int irq, void *data)
 464{
 465        /*
 466         * We cannot rely on the vgic maintenance interrupt to be
 467         * delivered synchronously. This means we can only use it to
 468         * exit the VM, and we perform the handling of EOIed
 469         * interrupts on the exit path (see vgic_fold_lr_state).
 470         */
 471        return IRQ_HANDLED;
 472}
 473
 474/**
 475 * kvm_vgic_init_cpu_hardware - initialize the GIC VE hardware
 476 *
 477 * For a specific CPU, initialize the GIC VE hardware.
 478 */
 479void kvm_vgic_init_cpu_hardware(void)
 480{
 481        BUG_ON(preemptible());
 482
 483        /*
 484         * We want to make sure the list registers start out clear so that we
 485         * only have the program the used registers.
 486         */
 487        if (kvm_vgic_global_state.type == VGIC_V2)
 488                vgic_v2_init_lrs();
 489        else
 490                kvm_call_hyp(__vgic_v3_init_lrs);
 491}
 492
 493/**
 494 * kvm_vgic_hyp_init: populates the kvm_vgic_global_state variable
 495 * according to the host GIC model. Accordingly calls either
 496 * vgic_v2/v3_probe which registers the KVM_DEVICE that can be
 497 * instantiated by a guest later on .
 498 */
 499int kvm_vgic_hyp_init(void)
 500{
 501        const struct gic_kvm_info *gic_kvm_info;
 502        int ret;
 503
 504        gic_kvm_info = gic_get_kvm_info();
 505        if (!gic_kvm_info)
 506                return -ENODEV;
 507
 508        if (!gic_kvm_info->maint_irq) {
 509                kvm_err("No vgic maintenance irq\n");
 510                return -ENXIO;
 511        }
 512
 513        switch (gic_kvm_info->type) {
 514        case GIC_V2:
 515                ret = vgic_v2_probe(gic_kvm_info);
 516                break;
 517        case GIC_V3:
 518                ret = vgic_v3_probe(gic_kvm_info);
 519                if (!ret) {
 520                        static_branch_enable(&kvm_vgic_global_state.gicv3_cpuif);
 521                        kvm_info("GIC system register CPU interface enabled\n");
 522                }
 523                break;
 524        default:
 525                ret = -ENODEV;
 526        }
 527
 528        if (ret)
 529                return ret;
 530
 531        kvm_vgic_global_state.maint_irq = gic_kvm_info->maint_irq;
 532        ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,
 533                                 vgic_maintenance_handler,
 534                                 "vgic", kvm_get_running_vcpus());
 535        if (ret) {
 536                kvm_err("Cannot register interrupt %d\n",
 537                        kvm_vgic_global_state.maint_irq);
 538                return ret;
 539        }
 540
 541        ret = cpuhp_setup_state(CPUHP_AP_KVM_ARM_VGIC_INIT_STARTING,
 542                                "kvm/arm/vgic:starting",
 543                                vgic_init_cpu_starting, vgic_init_cpu_dying);
 544        if (ret) {
 545                kvm_err("Cannot register vgic CPU notifier\n");
 546                goto out_free_irq;
 547        }
 548
 549        kvm_info("vgic interrupt IRQ%d\n", kvm_vgic_global_state.maint_irq);
 550        return 0;
 551
 552out_free_irq:
 553        free_percpu_irq(kvm_vgic_global_state.maint_irq,
 554                        kvm_get_running_vcpus());
 555        return ret;
 556}
 557