virt/kvm/arm/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, vcpu_lock_idx = -1, 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         /*
  90          * Any time a vcpu is run, vcpu_load is called which tries to grab the
  91          * vcpu->mutex.  By grabbing the vcpu->mutex of all VCPUs we ensure
  92          * that no other VCPUs are run while we create the vgic.
  93          */
  94         ret = -EBUSY;
  95         kvm_for_each_vcpu(i, vcpu, kvm) {
  96                 if (!mutex_trylock(&vcpu->mutex))
  97                         goto out_unlock;
  98                 vcpu_lock_idx = i;
  99         }
 100
 101         kvm_for_each_vcpu(i, vcpu, kvm) {
 102                 if (vcpu->arch.has_run_once)
 103                         goto out_unlock;
 104         }
 105         ret = 0;
 106
 107         if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
 108                 kvm->arch.max_vcpus = VGIC_V2_MAX_CPUS;
 109         else
 110                 kvm->arch.max_vcpus = VGIC_V3_MAX_CPUS;
 111
 112         if (atomic_read(&kvm->online_vcpus) > kvm->arch.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         for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
 129                 vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
 130                 mutex_unlock(&vcpu->mutex);
 131         }
 132         return ret;
 133 }
 134
 135 /* INIT/DESTROY */
 136
 137 /**
 138  * kvm_vgic_dist_init: initialize the dist data structures
 139  * @kvm: kvm struct pointer
 140  * @nr_spis: number of spis, frozen by caller
 141  */
 142 static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
 143 {
 144         struct vgic_dist *dist = &kvm->arch.vgic;
 145         struct kvm_vcpu *vcpu0 = kvm_get_vcpu(kvm, 0);
 146         int i;
 147
 148         dist->spis = kcalloc(nr_spis, sizeof(struct vgic_irq), GFP_KERNEL);
 149         if (!dist->spis)
 150                 return  -ENOMEM;
 151
 152         /*
 153          * In the following code we do not take the irq struct lock since
 154          * no other action on irq structs can happen while the VGIC is
 155          * not initialized yet:
 156          * If someone wants to inject an interrupt or does a MMIO access, we
 157          * require prior initialization in case of a virtual GICv3 or trigger
 158          * initialization when using a virtual GICv2.
 159          */
 160         for (i = 0; i < nr_spis; i++) {
 161                 struct vgic_irq *irq = &dist->spis[i];
 162
 163                 irq->intid = i + VGIC_NR_PRIVATE_IRQS;
 164                 INIT_LIST_HEAD(&irq->ap_list);
 165                 raw_spin_lock_init(&irq->irq_lock);
 166                 irq->vcpu = NULL;
 167                 irq->target_vcpu = vcpu0;
 168                 kref_init(&irq->refcount);
 169                 switch (dist->vgic_model) {
 170                 case KVM_DEV_TYPE_ARM_VGIC_V2:
 171                         irq->targets = 0;
 172                         irq->group = 0;
 173                         break;
 174                 case KVM_DEV_TYPE_ARM_VGIC_V3:
 175                         irq->mpidr = 0;
 176                         irq->group = 1;
 177                         break;
 178                 default:
 179                         kfree(dist->spis);
 180                         return -EINVAL;
 181                 }
 182         }
 183         return 0;
 184 }
 185
 186 /**
 187  * kvm_vgic_vcpu_init() - Initialize static VGIC VCPU data
 188  * structures and register VCPU-specific KVM iodevs
 189  *
 190  * @vcpu: pointer to the VCPU being created and initialized
 191  *
 192  * Only do initialization, but do not actually enable the
 193  * VGIC CPU interface
 194  */
 195 int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
 196 {
 197         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 198         struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
 199         int ret = 0;
 200         int i;
 201
 202         vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF;
 203
 204         INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
 205         raw_spin_lock_init(&vgic_cpu->ap_list_lock);
 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->lock);
 239                 ret = vgic_register_redist_iodev(vcpu);
 240                 mutex_unlock(&vcpu->kvm->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  * Must be called with kvm->lock held!
 262  */
 263 int vgic_init(struct kvm *kvm)
 264 {
 265         struct vgic_dist *dist = &kvm->arch.vgic;
 266         struct kvm_vcpu *vcpu;
 267         int ret = 0, i, idx;
 268
 269         if (vgic_initialized(kvm))
 270                 return 0;
 271
 272         /* Are we also in the middle of creating a VCPU? */
 273         if (kvm->created_vcpus != atomic_read(&kvm->online_vcpus))
 274                 return -EBUSY;
 275
 276         /* freeze the number of spis */
 277         if (!dist->nr_spis)
 278                 dist->nr_spis = VGIC_NR_IRQS_LEGACY - VGIC_NR_PRIVATE_IRQS;
 279
 280         ret = kvm_vgic_dist_init(kvm, dist->nr_spis);
 281         if (ret)
 282                 goto out;
 283
 284         /* Initialize groups on CPUs created before the VGIC type was known */
 285         kvm_for_each_vcpu(idx, vcpu, kvm) {
 286                 struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 287
 288                 for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
 289                         struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
 290                         switch (dist->vgic_model) {
 291                         case KVM_DEV_TYPE_ARM_VGIC_V3:
 292                                 irq->group = 1;
 293                                 irq->mpidr = kvm_vcpu_get_mpidr_aff(vcpu);
 294                                 break;
 295                         case KVM_DEV_TYPE_ARM_VGIC_V2:
 296                                 irq->group = 0;
 297                                 irq->targets = 1U << idx;
 298                                 break;
 299                         default:
 300                                 ret = -EINVAL;
 301                                 goto out;
 302                         }
 303                 }
 304         }
 305
 306         if (vgic_has_its(kvm)) {
 307                 vgic_lpi_translation_cache_init(kvm);
 308                 ret = vgic_v4_init(kvm);
 309                 if (ret)
 310                         goto out;
 311         }
 312
 313         kvm_for_each_vcpu(i, vcpu, kvm)
 314                 kvm_vgic_vcpu_enable(vcpu);
 315
 316         ret = kvm_vgic_setup_default_irq_routing(kvm);
 317         if (ret)
 318                 goto out;
 319
 320         vgic_debug_init(kvm);
 321
 322         dist->implementation_rev = 2;
 323         dist->initialized = true;
 324
 325 out:
 326         return ret;
 327 }
 328
 329 static void kvm_vgic_dist_destroy(struct kvm *kvm)
 330 {
 331         struct vgic_dist *dist = &kvm->arch.vgic;
 332         struct vgic_redist_region *rdreg, *next;
 333
 334         dist->ready = false;
 335         dist->initialized = false;
 336
 337         kfree(dist->spis);
 338         dist->spis = NULL;
 339         dist->nr_spis = 0;
 340
 341         if (kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
 342                 list_for_each_entry_safe(rdreg, next, &dist->rd_regions, list) {
 343                         list_del(&rdreg->list);
 344                         kfree(rdreg);
 345                 }
 346                 INIT_LIST_HEAD(&dist->rd_regions);
 347         }
 348
 349         if (vgic_has_its(kvm))
 350                 vgic_lpi_translation_cache_destroy(kvm);
 351
 352         if (vgic_supports_direct_msis(kvm))
 353                 vgic_v4_teardown(kvm);
 354 }
 355
 356 void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
 357 {
 358         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 359
 360         INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
 361 }
 362
 363 /* To be called with kvm->lock held */
 364 static void __kvm_vgic_destroy(struct kvm *kvm)
 365 {
 366         struct kvm_vcpu *vcpu;
 367         int i;
 368
 369         vgic_debug_destroy(kvm);
 370
 371         kvm_vgic_dist_destroy(kvm);
 372
 373         kvm_for_each_vcpu(i, vcpu, kvm)
 374                 kvm_vgic_vcpu_destroy(vcpu);
 375 }
 376
 377 void kvm_vgic_destroy(struct kvm *kvm)
 378 {
 379         mutex_lock(&kvm->lock);
 380         __kvm_vgic_destroy(kvm);
 381         mutex_unlock(&kvm->lock);
 382 }
 383
 384 /**
 385  * vgic_lazy_init: Lazy init is only allowed if the GIC exposed to the guest
 386  * is a GICv2. A GICv3 must be explicitly initialized by the guest using the
 387  * KVM_DEV_ARM_VGIC_GRP_CTRL KVM_DEVICE group.
 388  * @kvm: kvm struct pointer
 389  */
 390 int vgic_lazy_init(struct kvm *kvm)
 391 {
 392         int ret = 0;
 393
 394         if (unlikely(!vgic_initialized(kvm))) {
 395                 /*
 396                  * We only provide the automatic initialization of the VGIC
 397                  * for the legacy case of a GICv2. Any other type must
 398                  * be explicitly initialized once setup with the respective
 399                  * KVM device call.
 400                  */
 401                 if (kvm->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V2)
 402                         return -EBUSY;
 403
 404                 mutex_lock(&kvm->lock);
 405                 ret = vgic_init(kvm);
 406                 mutex_unlock(&kvm->lock);
 407         }
 408
 409         return ret;
 410 }
 411
 412 /* RESOURCE MAPPING */
 413
 414 /**
 415  * Map the MMIO regions depending on the VGIC model exposed to the guest
 416  * called on the first VCPU run.
 417  * Also map the virtual CPU interface into the VM.
 418  * v2/v3 derivatives call vgic_init if not already done.
 419  * vgic_ready() returns true if this function has succeeded.
 420  * @kvm: kvm struct pointer
 421  */
 422 int kvm_vgic_map_resources(struct kvm *kvm)
 423 {
 424         struct vgic_dist *dist = &kvm->arch.vgic;
 425         int ret = 0;
 426
 427         mutex_lock(&kvm->lock);
 428         if (!irqchip_in_kernel(kvm))
 429                 goto out;
 430
 431         if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
 432                 ret = vgic_v2_map_resources(kvm);
 433         else
 434                 ret = vgic_v3_map_resources(kvm);
 435
 436         if (ret)
 437                 __kvm_vgic_destroy(kvm);
 438
 439 out:
 440         mutex_unlock(&kvm->lock);
 441         return ret;
 442 }
 443
 444 /* GENERIC PROBE */
 445
 446 static int vgic_init_cpu_starting(unsigned int cpu)
 447 {
 448         enable_percpu_irq(kvm_vgic_global_state.maint_irq, 0);
 449         return 0;
 450 }
 451
 452
 453 static int vgic_init_cpu_dying(unsigned int cpu)
 454 {
 455         disable_percpu_irq(kvm_vgic_global_state.maint_irq);
 456         return 0;
 457 }
 458
 459 static irqreturn_t vgic_maintenance_handler(int irq, void *data)
 460 {
 461         /*
 462          * We cannot rely on the vgic maintenance interrupt to be
 463          * delivered synchronously. This means we can only use it to
 464          * exit the VM, and we perform the handling of EOIed
 465          * interrupts on the exit path (see vgic_fold_lr_state).
 466          */
 467         return IRQ_HANDLED;
 468 }
 469
 470 /**
 471  * kvm_vgic_init_cpu_hardware - initialize the GIC VE hardware
 472  *
 473  * For a specific CPU, initialize the GIC VE hardware.
 474  */
 475 void kvm_vgic_init_cpu_hardware(void)
 476 {
 477         BUG_ON(preemptible());
 478
 479         /*
 480          * We want to make sure the list registers start out clear so that we
 481          * only have the program the used registers.
 482          */
 483         if (kvm_vgic_global_state.type == VGIC_V2)
 484                 vgic_v2_init_lrs();
 485         else
 486                 kvm_call_hyp(__vgic_v3_init_lrs);
 487 }
 488
 489 /**
 490  * kvm_vgic_hyp_init: populates the kvm_vgic_global_state variable
 491  * according to the host GIC model. Accordingly calls either
 492  * vgic_v2/v3_probe which registers the KVM_DEVICE that can be
 493  * instantiated by a guest later on .
 494  */
 495 int kvm_vgic_hyp_init(void)
 496 {
 497         const struct gic_kvm_info *gic_kvm_info;
 498         int ret;
 499
 500         gic_kvm_info = gic_get_kvm_info();
 501         if (!gic_kvm_info)
 502                 return -ENODEV;
 503
 504         if (!gic_kvm_info->maint_irq) {
 505                 kvm_err("No vgic maintenance irq\n");
 506                 return -ENXIO;
 507         }
 508
 509         switch (gic_kvm_info->type) {
 510         case GIC_V2:
 511                 ret = vgic_v2_probe(gic_kvm_info);
 512                 break;
 513         case GIC_V3:
 514                 ret = vgic_v3_probe(gic_kvm_info);
 515                 if (!ret) {
 516                         static_branch_enable(&kvm_vgic_global_state.gicv3_cpuif);
 517                         kvm_info("GIC system register CPU interface enabled\n");
 518                 }
 519                 break;
 520         default:
 521                 ret = -ENODEV;
 522         }
 523
 524         if (ret)
 525                 return ret;
 526
 527         kvm_vgic_global_state.maint_irq = gic_kvm_info->maint_irq;
 528         ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,
 529                                  vgic_maintenance_handler,
 530                                  "vgic", kvm_get_running_vcpus());
 531         if (ret) {
 532                 kvm_err("Cannot register interrupt %d\n",
 533                         kvm_vgic_global_state.maint_irq);
 534                 return ret;
 535         }
 536
 537         ret = cpuhp_setup_state(CPUHP_AP_KVM_ARM_VGIC_INIT_STARTING,
 538                                 "kvm/arm/vgic:starting",
 539                                 vgic_init_cpu_starting, vgic_init_cpu_dying);
 540         if (ret) {
 541                 kvm_err("Cannot register vgic CPU notifier\n");
 542                 goto out_free_irq;
 543         }
 544
 545         kvm_info("vgic interrupt IRQ%d\n", kvm_vgic_global_state.maint_irq);
 546         return 0;
 547
 548 out_free_irq:
 549         free_percpu_irq(kvm_vgic_global_state.maint_irq,
 550                         kvm_get_running_vcpus());
 551         return ret;
 552 }