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_mmu.h>
  12 #include "vgic.h"
  13
  14 /*
  15  * Initialization rules: there are multiple stages to the vgic
  16  * initialization, both for the distributor and the CPU interfaces.  The basic
  17  * idea is that even though the VGIC is not functional or not requested from
  18  * user space, the critical path of the run loop can still call VGIC functions
  19  * that just won't do anything, without them having to check additional
  20  * initialization flags to ensure they don't look at uninitialized data
  21  * structures.
  22  *
  23  * Distributor:
  24  *
  25  * - kvm_vgic_early_init(): initialization of static data that doesn't
  26  *   depend on any sizing information or emulation type. No allocation
  27  *   is allowed there.
  28  *
  29  * - vgic_init(): allocation and initialization of the generic data
  30  *   structures that depend on sizing information (number of CPUs,
  31  *   number of interrupts). Also initializes the vcpu specific data
  32  *   structures. Can be executed lazily for GICv2.
  33  *
  34  * CPU Interface:
  35  *
  36  * - kvm_vgic_vcpu_init(): initialization of static data that
  37  *   doesn't depend on any sizing information or emulation type. No
  38  *   allocation is allowed there.
  39  */
  40
  41 /* EARLY INIT */
  42
  43 /**
  44  * kvm_vgic_early_init() - Initialize static VGIC VCPU data structures
  45  * @kvm: The VM whose VGIC districutor should be initialized
  46  *
  47  * Only do initialization of static structures that don't require any
  48  * allocation or sizing information from userspace.  vgic_init() called
  49  * kvm_vgic_dist_init() which takes care of the rest.
  50  */
  51 void kvm_vgic_early_init(struct kvm *kvm)
  52 {
  53         struct vgic_dist *dist = &kvm->arch.vgic;
  54
  55         INIT_LIST_HEAD(&dist->lpi_list_head);
  56         raw_spin_lock_init(&dist->lpi_list_lock);
  57 }
  58
  59 /* CREATION */
  60
  61 /**
  62  * kvm_vgic_create: triggered by the instantiation of the VGIC device by
  63  * user space, either through the legacy KVM_CREATE_IRQCHIP ioctl (v2 only)
  64  * or through the generic KVM_CREATE_DEVICE API ioctl.
  65  * irqchip_in_kernel() tells you if this function succeeded or not.
  66  * @kvm: kvm struct pointer
  67  * @type: KVM_DEV_TYPE_ARM_VGIC_V[23]
  68  */
  69 int kvm_vgic_create(struct kvm *kvm, u32 type)
  70 {
  71         int i, vcpu_lock_idx = -1, ret;
  72         struct kvm_vcpu *vcpu;
  73
  74         if (irqchip_in_kernel(kvm))
  75                 return -EEXIST;
  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         /*
  88          * Any time a vcpu is run, vcpu_load is called which tries to grab the
  89          * vcpu->mutex.  By grabbing the vcpu->mutex of all VCPUs we ensure
  90          * that no other VCPUs are run while we create the vgic.
  91          */
  92         ret = -EBUSY;
  93         kvm_for_each_vcpu(i, vcpu, kvm) {
  94                 if (!mutex_trylock(&vcpu->mutex))
  95                         goto out_unlock;
  96                 vcpu_lock_idx = i;
  97         }
  98
  99         kvm_for_each_vcpu(i, vcpu, kvm) {
 100                 if (vcpu->arch.has_run_once)
 101                         goto out_unlock;
 102         }
 103         ret = 0;
 104
 105         if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
 106                 kvm->arch.max_vcpus = VGIC_V2_MAX_CPUS;
 107         else
 108                 kvm->arch.max_vcpus = VGIC_V3_MAX_CPUS;
 109
 110         if (atomic_read(&kvm->online_vcpus) > kvm->arch.max_vcpus) {
 111                 ret = -E2BIG;
 112                 goto out_unlock;
 113         }
 114
 115         kvm->arch.vgic.in_kernel = true;
 116         kvm->arch.vgic.vgic_model = type;
 117
 118         kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
 119
 120         if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
 121                 kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
 122         else
 123                 INIT_LIST_HEAD(&kvm->arch.vgic.rd_regions);
 124
 125 out_unlock:
 126         for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
 127                 vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
 128                 mutex_unlock(&vcpu->mutex);
 129         }
 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);
 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                 if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2) {
 168                         irq->targets = 0;
 169                         irq->group = 0;
 170                 } else {
 171                         irq->mpidr = 0;
 172                         irq->group = 1;
 173                 }
 174         }
 175         return 0;
 176 }
 177
 178 /**
 179  * kvm_vgic_vcpu_init() - Initialize static VGIC VCPU data
 180  * structures and register VCPU-specific KVM iodevs
 181  *
 182  * @vcpu: pointer to the VCPU being created and initialized
 183  *
 184  * Only do initialization, but do not actually enable the
 185  * VGIC CPU interface
 186  */
 187 int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
 188 {
 189         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 190         struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
 191         int ret = 0;
 192         int i;
 193
 194         vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF;
 195         vgic_cpu->sgi_iodev.base_addr = VGIC_ADDR_UNDEF;
 196
 197         INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
 198         raw_spin_lock_init(&vgic_cpu->ap_list_lock);
 199
 200         /*
 201          * Enable and configure all SGIs to be edge-triggered and
 202          * configure all PPIs as level-triggered.
 203          */
 204         for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
 205                 struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
 206
 207                 INIT_LIST_HEAD(&irq->ap_list);
 208                 raw_spin_lock_init(&irq->irq_lock);
 209                 irq->intid = i;
 210                 irq->vcpu = NULL;
 211                 irq->target_vcpu = vcpu;
 212                 irq->targets = 1U << vcpu->vcpu_id;
 213                 kref_init(&irq->refcount);
 214                 if (vgic_irq_is_sgi(i)) {
 215                         /* SGIs */
 216                         irq->enabled = 1;
 217                         irq->config = VGIC_CONFIG_EDGE;
 218                 } else {
 219                         /* PPIs */
 220                         irq->config = VGIC_CONFIG_LEVEL;
 221                 }
 222
 223                 if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3)
 224                         irq->group = 1;
 225                 else
 226                         irq->group = 0;
 227         }
 228
 229         if (!irqchip_in_kernel(vcpu->kvm))
 230                 return 0;
 231
 232         /*
 233          * If we are creating a VCPU with a GICv3 we must also register the
 234          * KVM io device for the redistributor that belongs to this VCPU.
 235          */
 236         if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
 237                 mutex_lock(&vcpu->kvm->lock);
 238                 ret = vgic_register_redist_iodev(vcpu);
 239                 mutex_unlock(&vcpu->kvm->lock);
 240         }
 241         return ret;
 242 }
 243
 244 static void kvm_vgic_vcpu_enable(struct kvm_vcpu *vcpu)
 245 {
 246         if (kvm_vgic_global_state.type == VGIC_V2)
 247                 vgic_v2_enable(vcpu);
 248         else
 249                 vgic_v3_enable(vcpu);
 250 }
 251
 252 /*
 253  * vgic_init: allocates and initializes dist and vcpu data structures
 254  * depending on two dimensioning parameters:
 255  * - the number of spis
 256  * - the number of vcpus
 257  * The function is generally called when nr_spis has been explicitly set
 258  * by the guest through the KVM DEVICE API. If not nr_spis is set to 256.
 259  * vgic_initialized() returns true when this function has succeeded.
 260  * Must be called with kvm->lock held!
 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, idx;
 267
 268         if (vgic_initialized(kvm))
 269                 return 0;
 270
 271         /* Are we also in the middle of creating a VCPU? */
 272         if (kvm->created_vcpus != atomic_read(&kvm->online_vcpus))
 273                 return -EBUSY;
 274
 275         /* freeze the number of spis */
 276         if (!dist->nr_spis)
 277                 dist->nr_spis = VGIC_NR_IRQS_LEGACY - VGIC_NR_PRIVATE_IRQS;
 278
 279         ret = kvm_vgic_dist_init(kvm, dist->nr_spis);
 280         if (ret)
 281                 goto out;
 282
 283         /* Initialize groups on CPUs created before the VGIC type was known */
 284         kvm_for_each_vcpu(idx, vcpu, kvm) {
 285                 struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 286
 287                 for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
 288                         struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
 289                         if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3)
 290                                 irq->group = 1;
 291                         else
 292                                 irq->group = 0;
 293                 }
 294         }
 295
 296         if (vgic_has_its(kvm)) {
 297                 ret = vgic_v4_init(kvm);
 298                 if (ret)
 299                         goto out;
 300         }
 301
 302         kvm_for_each_vcpu(i, vcpu, kvm)
 303                 kvm_vgic_vcpu_enable(vcpu);
 304
 305         ret = kvm_vgic_setup_default_irq_routing(kvm);
 306         if (ret)
 307                 goto out;
 308
 309         vgic_debug_init(kvm);
 310
 311         dist->implementation_rev = 2;
 312         dist->initialized = true;
 313
 314 out:
 315         return ret;
 316 }
 317
 318 static void kvm_vgic_dist_destroy(struct kvm *kvm)
 319 {
 320         struct vgic_dist *dist = &kvm->arch.vgic;
 321         struct vgic_redist_region *rdreg, *next;
 322
 323         dist->ready = false;
 324         dist->initialized = false;
 325
 326         kfree(dist->spis);
 327         dist->spis = NULL;
 328         dist->nr_spis = 0;
 329
 330         if (kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
 331                 list_for_each_entry_safe(rdreg, next, &dist->rd_regions, list) {
 332                         list_del(&rdreg->list);
 333                         kfree(rdreg);
 334                 }
 335                 INIT_LIST_HEAD(&dist->rd_regions);
 336         }
 337
 338         if (vgic_supports_direct_msis(kvm))
 339                 vgic_v4_teardown(kvm);
 340 }
 341
 342 void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
 343 {
 344         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 345
 346         INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
 347 }
 348
 349 /* To be called with kvm->lock held */
 350 static void __kvm_vgic_destroy(struct kvm *kvm)
 351 {
 352         struct kvm_vcpu *vcpu;
 353         int i;
 354
 355         vgic_debug_destroy(kvm);
 356
 357         kvm_vgic_dist_destroy(kvm);
 358
 359         kvm_for_each_vcpu(i, vcpu, kvm)
 360                 kvm_vgic_vcpu_destroy(vcpu);
 361 }
 362
 363 void kvm_vgic_destroy(struct kvm *kvm)
 364 {
 365         mutex_lock(&kvm->lock);
 366         __kvm_vgic_destroy(kvm);
 367         mutex_unlock(&kvm->lock);
 368 }
 369
 370 /**
 371  * vgic_lazy_init: Lazy init is only allowed if the GIC exposed to the guest
 372  * is a GICv2. A GICv3 must be explicitly initialized by the guest using the
 373  * KVM_DEV_ARM_VGIC_GRP_CTRL KVM_DEVICE group.
 374  * @kvm: kvm struct pointer
 375  */
 376 int vgic_lazy_init(struct kvm *kvm)
 377 {
 378         int ret = 0;
 379
 380         if (unlikely(!vgic_initialized(kvm))) {
 381                 /*
 382                  * We only provide the automatic initialization of the VGIC
 383                  * for the legacy case of a GICv2. Any other type must
 384                  * be explicitly initialized once setup with the respective
 385                  * KVM device call.
 386                  */
 387                 if (kvm->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V2)
 388                         return -EBUSY;
 389
 390                 mutex_lock(&kvm->lock);
 391                 ret = vgic_init(kvm);
 392                 mutex_unlock(&kvm->lock);
 393         }
 394
 395         return ret;
 396 }
 397
 398 /* RESOURCE MAPPING */
 399
 400 /**
 401  * Map the MMIO regions depending on the VGIC model exposed to the guest
 402  * called on the first VCPU run.
 403  * Also map the virtual CPU interface into the VM.
 404  * v2/v3 derivatives call vgic_init if not already done.
 405  * vgic_ready() returns true if this function has succeeded.
 406  * @kvm: kvm struct pointer
 407  */
 408 int kvm_vgic_map_resources(struct kvm *kvm)
 409 {
 410         struct vgic_dist *dist = &kvm->arch.vgic;
 411         int ret = 0;
 412
 413         mutex_lock(&kvm->lock);
 414         if (!irqchip_in_kernel(kvm))
 415                 goto out;
 416
 417         if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
 418                 ret = vgic_v2_map_resources(kvm);
 419         else
 420                 ret = vgic_v3_map_resources(kvm);
 421
 422         if (ret)
 423                 __kvm_vgic_destroy(kvm);
 424
 425 out:
 426         mutex_unlock(&kvm->lock);
 427         return ret;
 428 }
 429
 430 /* GENERIC PROBE */
 431
 432 static int vgic_init_cpu_starting(unsigned int cpu)
 433 {
 434         enable_percpu_irq(kvm_vgic_global_state.maint_irq, 0);
 435         return 0;
 436 }
 437
 438
 439 static int vgic_init_cpu_dying(unsigned int cpu)
 440 {
 441         disable_percpu_irq(kvm_vgic_global_state.maint_irq);
 442         return 0;
 443 }
 444
 445 static irqreturn_t vgic_maintenance_handler(int irq, void *data)
 446 {
 447         /*
 448          * We cannot rely on the vgic maintenance interrupt to be
 449          * delivered synchronously. This means we can only use it to
 450          * exit the VM, and we perform the handling of EOIed
 451          * interrupts on the exit path (see vgic_fold_lr_state).
 452          */
 453         return IRQ_HANDLED;
 454 }
 455
 456 /**
 457  * kvm_vgic_init_cpu_hardware - initialize the GIC VE hardware
 458  *
 459  * For a specific CPU, initialize the GIC VE hardware.
 460  */
 461 void kvm_vgic_init_cpu_hardware(void)
 462 {
 463         BUG_ON(preemptible());
 464
 465         /*
 466          * We want to make sure the list registers start out clear so that we
 467          * only have the program the used registers.
 468          */
 469         if (kvm_vgic_global_state.type == VGIC_V2)
 470                 vgic_v2_init_lrs();
 471         else
 472                 kvm_call_hyp(__vgic_v3_init_lrs);
 473 }
 474
 475 /**
 476  * kvm_vgic_hyp_init: populates the kvm_vgic_global_state variable
 477  * according to the host GIC model. Accordingly calls either
 478  * vgic_v2/v3_probe which registers the KVM_DEVICE that can be
 479  * instantiated by a guest later on .
 480  */
 481 int kvm_vgic_hyp_init(void)
 482 {
 483         const struct gic_kvm_info *gic_kvm_info;
 484         int ret;
 485
 486         gic_kvm_info = gic_get_kvm_info();
 487         if (!gic_kvm_info)
 488                 return -ENODEV;
 489
 490         if (!gic_kvm_info->maint_irq) {
 491                 kvm_err("No vgic maintenance irq\n");
 492                 return -ENXIO;
 493         }
 494
 495         switch (gic_kvm_info->type) {
 496         case GIC_V2:
 497                 ret = vgic_v2_probe(gic_kvm_info);
 498                 break;
 499         case GIC_V3:
 500                 ret = vgic_v3_probe(gic_kvm_info);
 501                 if (!ret) {
 502                         static_branch_enable(&kvm_vgic_global_state.gicv3_cpuif);
 503                         kvm_info("GIC system register CPU interface enabled\n");
 504                 }
 505                 break;
 506         default:
 507                 ret = -ENODEV;
 508         };
 509
 510         if (ret)
 511                 return ret;
 512
 513         kvm_vgic_global_state.maint_irq = gic_kvm_info->maint_irq;
 514         ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,
 515                                  vgic_maintenance_handler,
 516                                  "vgic", kvm_get_running_vcpus());
 517         if (ret) {
 518                 kvm_err("Cannot register interrupt %d\n",
 519                         kvm_vgic_global_state.maint_irq);
 520                 return ret;
 521         }
 522
 523         ret = cpuhp_setup_state(CPUHP_AP_KVM_ARM_VGIC_INIT_STARTING,
 524                                 "kvm/arm/vgic:starting",
 525                                 vgic_init_cpu_starting, vgic_init_cpu_dying);
 526         if (ret) {
 527                 kvm_err("Cannot register vgic CPU notifier\n");
 528                 goto out_free_irq;
 529         }
 530
 531         kvm_info("vgic interrupt IRQ%d\n", kvm_vgic_global_state.maint_irq);
 532         return 0;
 533
 534 out_free_irq:
 535         free_percpu_irq(kvm_vgic_global_state.maint_irq,
 536                         kvm_get_running_vcpus());
 537         return ret;
 538 }