arch/arm64/kvm/vgic/vgic-init.c

   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  */
  52 void 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  */
  71 int kvm_vgic_create(struct kvm *kvm, u32 type)
  72 {
  73         struct kvm_vcpu *vcpu;
  74         unsigned long i;
  75         int ret;
  76
  77         /*
  78          * This function is also called by the KVM_CREATE_IRQCHIP handler,
  79          * which had no chance yet to check the availability of the GICv2
  80          * emulation. So check this here again. KVM_CREATE_DEVICE does
  81          * the proper checks already.
  82          */
  83         if (type == KVM_DEV_TYPE_ARM_VGIC_V2 &&
  84                 !kvm_vgic_global_state.can_emulate_gicv2)
  85                 return -ENODEV;
  86
  87         /* Must be held to avoid race with vCPU creation */
  88         lockdep_assert_held(&kvm->lock);
  89
  90         ret = -EBUSY;
  91         if (!lock_all_vcpus(kvm))
  92                 return ret;
  93
  94         mutex_lock(&kvm->arch.config_lock);
  95
  96         if (irqchip_in_kernel(kvm)) {
  97                 ret = -EEXIST;
  98                 goto out_unlock;
  99         }
 100
 101         kvm_for_each_vcpu(i, vcpu, kvm) {
 102                 if (vcpu_has_run_once(vcpu))
 103                         goto out_unlock;
 104         }
 105         ret = 0;
 106
 107         if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
 108                 kvm->max_vcpus = VGIC_V2_MAX_CPUS;
 109         else
 110                 kvm->max_vcpus = VGIC_V3_MAX_CPUS;
 111
 112         if (atomic_read(&kvm->online_vcpus) > kvm->max_vcpus) {
 113                 ret = -E2BIG;
 114                 goto out_unlock;
 115         }
 116
 117         kvm->arch.vgic.in_kernel = true;
 118         kvm->arch.vgic.vgic_model = type;
 119
 120         kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
 121
 122         if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
 123                 kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
 124         else
 125                 INIT_LIST_HEAD(&kvm->arch.vgic.rd_regions);
 126
 127 out_unlock:
 128         mutex_unlock(&kvm->arch.config_lock);
 129         unlock_all_vcpus(kvm);
 130         return ret;
 131 }
 132
 133 /* INIT/DESTROY */
 134
 135 /**
 136  * kvm_vgic_dist_init: initialize the dist data structures
 137  * @kvm: kvm struct pointer
 138  * @nr_spis: number of spis, frozen by caller
 139  */
 140 static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
 141 {
 142         struct vgic_dist *dist = &kvm->arch.vgic;
 143         struct kvm_vcpu *vcpu0 = kvm_get_vcpu(kvm, 0);
 144         int i;
 145
 146         dist->spis = kcalloc(nr_spis, sizeof(struct vgic_irq), GFP_KERNEL_ACCOUNT);
 147         if (!dist->spis)
 148                 return  -ENOMEM;
 149
 150         /*
 151          * In the following code we do not take the irq struct lock since
 152          * no other action on irq structs can happen while the VGIC is
 153          * not initialized yet:
 154          * If someone wants to inject an interrupt or does a MMIO access, we
 155          * require prior initialization in case of a virtual GICv3 or trigger
 156          * initialization when using a virtual GICv2.
 157          */
 158         for (i = 0; i < nr_spis; i++) {
 159                 struct vgic_irq *irq = &dist->spis[i];
 160
 161                 irq->intid = i + VGIC_NR_PRIVATE_IRQS;
 162                 INIT_LIST_HEAD(&irq->ap_list);
 163                 raw_spin_lock_init(&irq->irq_lock);
 164                 irq->vcpu = NULL;
 165                 irq->target_vcpu = vcpu0;
 166                 kref_init(&irq->refcount);
 167                 switch (dist->vgic_model) {
 168                 case KVM_DEV_TYPE_ARM_VGIC_V2:
 169                         irq->targets = 0;
 170                         irq->group = 0;
 171                         break;
 172                 case KVM_DEV_TYPE_ARM_VGIC_V3:
 173                         irq->mpidr = 0;
 174                         irq->group = 1;
 175                         break;
 176                 default:
 177                         kfree(dist->spis);
 178                         dist->spis = NULL;
 179                         return -EINVAL;
 180                 }
 181         }
 182         return 0;
 183 }
 184
 185 /**
 186  * kvm_vgic_vcpu_init() - Initialize static VGIC VCPU data
 187  * structures and register VCPU-specific KVM iodevs
 188  *
 189  * @vcpu: pointer to the VCPU being created and initialized
 190  *
 191  * Only do initialization, but do not actually enable the
 192  * VGIC CPU interface
 193  */
 194 int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
 195 {
 196         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 197         struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
 198         int ret = 0;
 199         int i;
 200
 201         vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF;
 202
 203         INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
 204         raw_spin_lock_init(&vgic_cpu->ap_list_lock);
 205         atomic_set(&vgic_cpu->vgic_v3.its_vpe.vlpi_count, 0);
 206
 207         /*
 208          * Enable and configure all SGIs to be edge-triggered and
 209          * configure all PPIs as level-triggered.
 210          */
 211         for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
 212                 struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
 213
 214                 INIT_LIST_HEAD(&irq->ap_list);
 215                 raw_spin_lock_init(&irq->irq_lock);
 216                 irq->intid = i;
 217                 irq->vcpu = NULL;
 218                 irq->target_vcpu = vcpu;
 219                 kref_init(&irq->refcount);
 220                 if (vgic_irq_is_sgi(i)) {
 221                         /* SGIs */
 222                         irq->enabled = 1;
 223                         irq->config = VGIC_CONFIG_EDGE;
 224                 } else {
 225                         /* PPIs */
 226                         irq->config = VGIC_CONFIG_LEVEL;
 227                 }
 228         }
 229
 230         if (!irqchip_in_kernel(vcpu->kvm))
 231                 return 0;
 232
 233         /*
 234          * If we are creating a VCPU with a GICv3 we must also register the
 235          * KVM io device for the redistributor that belongs to this VCPU.
 236          */
 237         if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
 238                 mutex_lock(&vcpu->kvm->slots_lock);
 239                 ret = vgic_register_redist_iodev(vcpu);
 240                 mutex_unlock(&vcpu->kvm->slots_lock);
 241         }
 242         return ret;
 243 }
 244
 245 static void kvm_vgic_vcpu_enable(struct kvm_vcpu *vcpu)
 246 {
 247         if (kvm_vgic_global_state.type == VGIC_V2)
 248                 vgic_v2_enable(vcpu);
 249         else
 250                 vgic_v3_enable(vcpu);
 251 }
 252
 253 /*
 254  * vgic_init: allocates and initializes dist and vcpu data structures
 255  * depending on two dimensioning parameters:
 256  * - the number of spis
 257  * - the number of vcpus
 258  * The function is generally called when nr_spis has been explicitly set
 259  * by the guest through the KVM DEVICE API. If not nr_spis is set to 256.
 260  * vgic_initialized() returns true when this function has succeeded.
 261  */
 262 int vgic_init(struct kvm *kvm)
 263 {
 264         struct vgic_dist *dist = &kvm->arch.vgic;
 265         struct kvm_vcpu *vcpu;
 266         int ret = 0, i;
 267         unsigned long idx;
 268
 269         lockdep_assert_held(&kvm->arch.config_lock);
 270
 271         if (vgic_initialized(kvm))
 272                 return 0;
 273
 274         /* Are we also in the middle of creating a VCPU? */
 275         if (kvm->created_vcpus != atomic_read(&kvm->online_vcpus))
 276                 return -EBUSY;
 277
 278         /* freeze the number of spis */
 279         if (!dist->nr_spis)
 280                 dist->nr_spis = VGIC_NR_IRQS_LEGACY - VGIC_NR_PRIVATE_IRQS;
 281
 282         ret = kvm_vgic_dist_init(kvm, dist->nr_spis);
 283         if (ret)
 284                 goto out;
 285
 286         /* Initialize groups on CPUs created before the VGIC type was known */
 287         kvm_for_each_vcpu(idx, vcpu, kvm) {
 288                 struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 289
 290                 for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
 291                         struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
 292                         switch (dist->vgic_model) {
 293                         case KVM_DEV_TYPE_ARM_VGIC_V3:
 294                                 irq->group = 1;
 295                                 irq->mpidr = kvm_vcpu_get_mpidr_aff(vcpu);
 296                                 break;
 297                         case KVM_DEV_TYPE_ARM_VGIC_V2:
 298                                 irq->group = 0;
 299                                 irq->targets = 1U << idx;
 300                                 break;
 301                         default:
 302                                 ret = -EINVAL;
 303                                 goto out;
 304                         }
 305                 }
 306         }
 307
 308         if (vgic_has_its(kvm))
 309                 vgic_lpi_translation_cache_init(kvm);
 310
 311         /*
 312          * If we have GICv4.1 enabled, unconditionnaly request enable the
 313          * v4 support so that we get HW-accelerated vSGIs. Otherwise, only
 314          * enable it if we present a virtual ITS to the guest.
 315          */
 316         if (vgic_supports_direct_msis(kvm)) {
 317                 ret = vgic_v4_init(kvm);
 318                 if (ret)
 319                         goto out;
 320         }
 321
 322         kvm_for_each_vcpu(idx, vcpu, kvm)
 323                 kvm_vgic_vcpu_enable(vcpu);
 324
 325         ret = kvm_vgic_setup_default_irq_routing(kvm);
 326         if (ret)
 327                 goto out;
 328
 329         vgic_debug_init(kvm);
 330
 331         /*
 332          * If userspace didn't set the GIC implementation revision,
 333          * default to the latest and greatest. You know want it.
 334          */
 335         if (!dist->implementation_rev)
 336                 dist->implementation_rev = KVM_VGIC_IMP_REV_LATEST;
 337         dist->initialized = true;
 338
 339 out:
 340         return ret;
 341 }
 342
 343 static void kvm_vgic_dist_destroy(struct kvm *kvm)
 344 {
 345         struct vgic_dist *dist = &kvm->arch.vgic;
 346         struct vgic_redist_region *rdreg, *next;
 347
 348         dist->ready = false;
 349         dist->initialized = false;
 350
 351         kfree(dist->spis);
 352         dist->spis = NULL;
 353         dist->nr_spis = 0;
 354         dist->vgic_dist_base = VGIC_ADDR_UNDEF;
 355
 356         if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
 357                 list_for_each_entry_safe(rdreg, next, &dist->rd_regions, list)
 358                         vgic_v3_free_redist_region(rdreg);
 359                 INIT_LIST_HEAD(&dist->rd_regions);
 360         } else {
 361                 dist->vgic_cpu_base = VGIC_ADDR_UNDEF;
 362         }
 363
 364         if (vgic_has_its(kvm))
 365                 vgic_lpi_translation_cache_destroy(kvm);
 366
 367         if (vgic_supports_direct_msis(kvm))
 368                 vgic_v4_teardown(kvm);
 369 }
 370
 371 static void __kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
 372 {
 373         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 374
 375         /*
 376          * Retire all pending LPIs on this vcpu anyway as we're
 377          * going to destroy it.
 378          */
 379         vgic_flush_pending_lpis(vcpu);
 380
 381         INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
 382         if (vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
 383                 vgic_unregister_redist_iodev(vcpu);
 384                 vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF;
 385         }
 386 }
 387
 388 void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
 389 {
 390         struct kvm *kvm = vcpu->kvm;
 391
 392         mutex_lock(&kvm->slots_lock);
 393         __kvm_vgic_vcpu_destroy(vcpu);
 394         mutex_unlock(&kvm->slots_lock);
 395 }
 396
 397 void kvm_vgic_destroy(struct kvm *kvm)
 398 {
 399         struct kvm_vcpu *vcpu;
 400         unsigned long i;
 401
 402         mutex_lock(&kvm->slots_lock);
 403
 404         vgic_debug_destroy(kvm);
 405
 406         kvm_for_each_vcpu(i, vcpu, kvm)
 407                 __kvm_vgic_vcpu_destroy(vcpu);
 408
 409         mutex_lock(&kvm->arch.config_lock);
 410
 411         kvm_vgic_dist_destroy(kvm);
 412
 413         mutex_unlock(&kvm->arch.config_lock);
 414         mutex_unlock(&kvm->slots_lock);
 415 }
 416
 417 /**
 418  * vgic_lazy_init: Lazy init is only allowed if the GIC exposed to the guest
 419  * is a GICv2. A GICv3 must be explicitly initialized by userspace using the
 420  * KVM_DEV_ARM_VGIC_GRP_CTRL KVM_DEVICE group.
 421  * @kvm: kvm struct pointer
 422  */
 423 int vgic_lazy_init(struct kvm *kvm)
 424 {
 425         int ret = 0;
 426
 427         if (unlikely(!vgic_initialized(kvm))) {
 428                 /*
 429                  * We only provide the automatic initialization of the VGIC
 430                  * for the legacy case of a GICv2. Any other type must
 431                  * be explicitly initialized once setup with the respective
 432                  * KVM device call.
 433                  */
 434                 if (kvm->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V2)
 435                         return -EBUSY;
 436
 437                 mutex_lock(&kvm->arch.config_lock);
 438                 ret = vgic_init(kvm);
 439                 mutex_unlock(&kvm->arch.config_lock);
 440         }
 441
 442         return ret;
 443 }
 444
 445 /* RESOURCE MAPPING */
 446
 447 /**
 448  * Map the MMIO regions depending on the VGIC model exposed to the guest
 449  * called on the first VCPU run.
 450  * Also map the virtual CPU interface into the VM.
 451  * v2 calls vgic_init() if not already done.
 452  * v3 and derivatives return an error if the VGIC is not initialized.
 453  * vgic_ready() returns true if this function has succeeded.
 454  * @kvm: kvm struct pointer
 455  */
 456 int kvm_vgic_map_resources(struct kvm *kvm)
 457 {
 458         struct vgic_dist *dist = &kvm->arch.vgic;
 459         enum vgic_type type;
 460         gpa_t dist_base;
 461         int ret = 0;
 462
 463         if (likely(vgic_ready(kvm)))
 464                 return 0;
 465
 466         mutex_lock(&kvm->slots_lock);
 467         mutex_lock(&kvm->arch.config_lock);
 468         if (vgic_ready(kvm))
 469                 goto out;
 470
 471         if (!irqchip_in_kernel(kvm))
 472                 goto out;
 473
 474         if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2) {
 475                 ret = vgic_v2_map_resources(kvm);
 476                 type = VGIC_V2;
 477         } else {
 478                 ret = vgic_v3_map_resources(kvm);
 479                 type = VGIC_V3;
 480         }
 481
 482         if (ret)
 483                 goto out;
 484
 485         dist->ready = true;
 486         dist_base = dist->vgic_dist_base;
 487         mutex_unlock(&kvm->arch.config_lock);
 488
 489         ret = vgic_register_dist_iodev(kvm, dist_base, type);
 490         if (ret)
 491                 kvm_err("Unable to register VGIC dist MMIO regions\n");
 492
 493         goto out_slots;
 494 out:
 495         mutex_unlock(&kvm->arch.config_lock);
 496 out_slots:
 497         mutex_unlock(&kvm->slots_lock);
 498
 499         if (ret)
 500                 kvm_vgic_destroy(kvm);
 501
 502         return ret;
 503 }
 504
 505 /* GENERIC PROBE */
 506
 507 void kvm_vgic_cpu_up(void)
 508 {
 509         enable_percpu_irq(kvm_vgic_global_state.maint_irq, 0);
 510 }
 511
 512
 513 void kvm_vgic_cpu_down(void)
 514 {
 515         disable_percpu_irq(kvm_vgic_global_state.maint_irq);
 516 }
 517
 518 static irqreturn_t vgic_maintenance_handler(int irq, void *data)
 519 {
 520         /*
 521          * We cannot rely on the vgic maintenance interrupt to be
 522          * delivered synchronously. This means we can only use it to
 523          * exit the VM, and we perform the handling of EOIed
 524          * interrupts on the exit path (see vgic_fold_lr_state).
 525          */
 526         return IRQ_HANDLED;
 527 }
 528
 529 static struct gic_kvm_info *gic_kvm_info;
 530
 531 void __init vgic_set_kvm_info(const struct gic_kvm_info *info)
 532 {
 533         BUG_ON(gic_kvm_info != NULL);
 534         gic_kvm_info = kmalloc(sizeof(*info), GFP_KERNEL);
 535         if (gic_kvm_info)
 536                 *gic_kvm_info = *info;
 537 }
 538
 539 /**
 540  * kvm_vgic_init_cpu_hardware - initialize the GIC VE hardware
 541  *
 542  * For a specific CPU, initialize the GIC VE hardware.
 543  */
 544 void kvm_vgic_init_cpu_hardware(void)
 545 {
 546         BUG_ON(preemptible());
 547
 548         /*
 549          * We want to make sure the list registers start out clear so that we
 550          * only have the program the used registers.
 551          */
 552         if (kvm_vgic_global_state.type == VGIC_V2)
 553                 vgic_v2_init_lrs();
 554         else
 555                 kvm_call_hyp(__vgic_v3_init_lrs);
 556 }
 557
 558 /**
 559  * kvm_vgic_hyp_init: populates the kvm_vgic_global_state variable
 560  * according to the host GIC model. Accordingly calls either
 561  * vgic_v2/v3_probe which registers the KVM_DEVICE that can be
 562  * instantiated by a guest later on .
 563  */
 564 int kvm_vgic_hyp_init(void)
 565 {
 566         bool has_mask;
 567         int ret;
 568
 569         if (!gic_kvm_info)
 570                 return -ENODEV;
 571
 572         has_mask = !gic_kvm_info->no_maint_irq_mask;
 573
 574         if (has_mask && !gic_kvm_info->maint_irq) {
 575                 kvm_err("No vgic maintenance irq\n");
 576                 return -ENXIO;
 577         }
 578
 579         /*
 580          * If we get one of these oddball non-GICs, taint the kernel,
 581          * as we have no idea of how they *really* behave.
 582          */
 583         if (gic_kvm_info->no_hw_deactivation) {
 584                 kvm_info("Non-architectural vgic, tainting kernel\n");
 585                 add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
 586                 kvm_vgic_global_state.no_hw_deactivation = true;
 587         }
 588
 589         switch (gic_kvm_info->type) {
 590         case GIC_V2:
 591                 ret = vgic_v2_probe(gic_kvm_info);
 592                 break;
 593         case GIC_V3:
 594                 ret = vgic_v3_probe(gic_kvm_info);
 595                 if (!ret) {
 596                         static_branch_enable(&kvm_vgic_global_state.gicv3_cpuif);
 597                         kvm_info("GIC system register CPU interface enabled\n");
 598                 }
 599                 break;
 600         default:
 601                 ret = -ENODEV;
 602         }
 603
 604         kvm_vgic_global_state.maint_irq = gic_kvm_info->maint_irq;
 605
 606         kfree(gic_kvm_info);
 607         gic_kvm_info = NULL;
 608
 609         if (ret)
 610                 return ret;
 611
 612         if (!has_mask && !kvm_vgic_global_state.maint_irq)
 613                 return 0;
 614
 615         ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,
 616                                  vgic_maintenance_handler,
 617                                  "vgic", kvm_get_running_vcpus());
 618         if (ret) {
 619                 kvm_err("Cannot register interrupt %d\n",
 620                         kvm_vgic_global_state.maint_irq);
 621                 return ret;
 622         }
 623
 624         kvm_info("vgic interrupt IRQ%d\n", kvm_vgic_global_state.maint_irq);
 625         return 0;
 626 }