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         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
 119 out_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  */
 131 static 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  */
 185 int 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
 236 static 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  */
 254 int 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
 323 out:
 324         return ret;
 325 }
 326
 327 static 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
 355 void 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 */
 370 static 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
 383 void 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  */
 396 int 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  */
 429 int 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
 454 out:
 455         mutex_unlock(&kvm->lock);
 456         return ret;
 457 }
 458
 459 /* GENERIC PROBE */
 460
 461 static 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
 468 static int vgic_init_cpu_dying(unsigned int cpu)
 469 {
 470         disable_percpu_irq(kvm_vgic_global_state.maint_irq);
 471         return 0;
 472 }
 473
 474 static 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
 485 static struct gic_kvm_info *gic_kvm_info;
 486
 487 void __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  */
 500 void 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  */
 520 int 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
 591 out_free_irq:
 592         free_percpu_irq(kvm_vgic_global_state.maint_irq,
 593                         kvm_get_running_vcpus());
 594         return ret;
 595 }