virt/kvm/arm/vgic/vgic-init.c

   1 /*
   2  * Copyright (C) 2015, 2016 ARM Ltd.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <linux/uaccess.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/cpu.h>
  20 #include <linux/kvm_host.h>
  21 #include <kvm/arm_vgic.h>
  22 #include <asm/kvm_mmu.h>
  23 #include "vgic.h"
  24
  25 /*
  26  * Initialization rules: there are multiple stages to the vgic
  27  * initialization, both for the distributor and the CPU interfaces.  The basic
  28  * idea is that even though the VGIC is not functional or not requested from
  29  * user space, the critical path of the run loop can still call VGIC functions
  30  * that just won't do anything, without them having to check additional
  31  * initialization flags to ensure they don't look at uninitialized data
  32  * structures.
  33  *
  34  * Distributor:
  35  *
  36  * - kvm_vgic_early_init(): initialization of static data that doesn't
  37  *   depend on any sizing information or emulation type. No allocation
  38  *   is allowed there.
  39  *
  40  * - vgic_init(): allocation and initialization of the generic data
  41  *   structures that depend on sizing information (number of CPUs,
  42  *   number of interrupts). Also initializes the vcpu specific data
  43  *   structures. Can be executed lazily for GICv2.
  44  *
  45  * CPU Interface:
  46  *
  47  * - kvm_vgic_vcpu_init(): initialization of static data that
  48  *   doesn't depend on any sizing information or emulation type. No
  49  *   allocation is allowed there.
  50  */
  51
  52 /* EARLY INIT */
  53
  54 /**
  55  * kvm_vgic_early_init() - Initialize static VGIC VCPU data structures
  56  * @kvm: The VM whose VGIC districutor should be initialized
  57  *
  58  * Only do initialization of static structures that don't require any
  59  * allocation or sizing information from userspace.  vgic_init() called
  60  * kvm_vgic_dist_init() which takes care of the rest.
  61  */
  62 void kvm_vgic_early_init(struct kvm *kvm)
  63 {
  64         struct vgic_dist *dist = &kvm->arch.vgic;
  65
  66         INIT_LIST_HEAD(&dist->lpi_list_head);
  67         spin_lock_init(&dist->lpi_list_lock);
  68 }
  69
  70 /* CREATION */
  71
  72 /**
  73  * kvm_vgic_create: triggered by the instantiation of the VGIC device by
  74  * user space, either through the legacy KVM_CREATE_IRQCHIP ioctl (v2 only)
  75  * or through the generic KVM_CREATE_DEVICE API ioctl.
  76  * irqchip_in_kernel() tells you if this function succeeded or not.
  77  * @kvm: kvm struct pointer
  78  * @type: KVM_DEV_TYPE_ARM_VGIC_V[23]
  79  */
  80 int kvm_vgic_create(struct kvm *kvm, u32 type)
  81 {
  82         int i, vcpu_lock_idx = -1, ret;
  83         struct kvm_vcpu *vcpu;
  84
  85         if (irqchip_in_kernel(kvm))
  86                 return -EEXIST;
  87
  88         /*
  89          * This function is also called by the KVM_CREATE_IRQCHIP handler,
  90          * which had no chance yet to check the availability of the GICv2
  91          * emulation. So check this here again. KVM_CREATE_DEVICE does
  92          * the proper checks already.
  93          */
  94         if (type == KVM_DEV_TYPE_ARM_VGIC_V2 &&
  95                 !kvm_vgic_global_state.can_emulate_gicv2)
  96                 return -ENODEV;
  97
  98         /*
  99          * Any time a vcpu is run, vcpu_load is called which tries to grab the
 100          * vcpu->mutex.  By grabbing the vcpu->mutex of all VCPUs we ensure
 101          * that no other VCPUs are run while we create the vgic.
 102          */
 103         ret = -EBUSY;
 104         kvm_for_each_vcpu(i, vcpu, kvm) {
 105                 if (!mutex_trylock(&vcpu->mutex))
 106                         goto out_unlock;
 107                 vcpu_lock_idx = i;
 108         }
 109
 110         kvm_for_each_vcpu(i, vcpu, kvm) {
 111                 if (vcpu->arch.has_run_once)
 112                         goto out_unlock;
 113         }
 114         ret = 0;
 115
 116         if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
 117                 kvm->arch.max_vcpus = VGIC_V2_MAX_CPUS;
 118         else
 119                 kvm->arch.max_vcpus = VGIC_V3_MAX_CPUS;
 120
 121         if (atomic_read(&kvm->online_vcpus) > kvm->arch.max_vcpus) {
 122                 ret = -E2BIG;
 123                 goto out_unlock;
 124         }
 125
 126         kvm->arch.vgic.in_kernel = true;
 127         kvm->arch.vgic.vgic_model = type;
 128
 129         kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
 130
 131         if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
 132                 kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
 133         else
 134                 INIT_LIST_HEAD(&kvm->arch.vgic.rd_regions);
 135
 136 out_unlock:
 137         for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
 138                 vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
 139                 mutex_unlock(&vcpu->mutex);
 140         }
 141         return ret;
 142 }
 143
 144 /* INIT/DESTROY */
 145
 146 /**
 147  * kvm_vgic_dist_init: initialize the dist data structures
 148  * @kvm: kvm struct pointer
 149  * @nr_spis: number of spis, frozen by caller
 150  */
 151 static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
 152 {
 153         struct vgic_dist *dist = &kvm->arch.vgic;
 154         struct kvm_vcpu *vcpu0 = kvm_get_vcpu(kvm, 0);
 155         int i;
 156
 157         dist->spis = kcalloc(nr_spis, sizeof(struct vgic_irq), GFP_KERNEL);
 158         if (!dist->spis)
 159                 return  -ENOMEM;
 160
 161         /*
 162          * In the following code we do not take the irq struct lock since
 163          * no other action on irq structs can happen while the VGIC is
 164          * not initialized yet:
 165          * If someone wants to inject an interrupt or does a MMIO access, we
 166          * require prior initialization in case of a virtual GICv3 or trigger
 167          * initialization when using a virtual GICv2.
 168          */
 169         for (i = 0; i < nr_spis; i++) {
 170                 struct vgic_irq *irq = &dist->spis[i];
 171
 172                 irq->intid = i + VGIC_NR_PRIVATE_IRQS;
 173                 INIT_LIST_HEAD(&irq->ap_list);
 174                 spin_lock_init(&irq->irq_lock);
 175                 irq->vcpu = NULL;
 176                 irq->target_vcpu = vcpu0;
 177                 kref_init(&irq->refcount);
 178                 if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2) {
 179                         irq->targets = 0;
 180                         irq->group = 0;
 181                 } else {
 182                         irq->mpidr = 0;
 183                         irq->group = 1;
 184                 }
 185         }
 186         return 0;
 187 }
 188
 189 /**
 190  * kvm_vgic_vcpu_init() - Initialize static VGIC VCPU data
 191  * structures and register VCPU-specific KVM iodevs
 192  *
 193  * @vcpu: pointer to the VCPU being created and initialized
 194  *
 195  * Only do initialization, but do not actually enable the
 196  * VGIC CPU interface
 197  */
 198 int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
 199 {
 200         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 201         struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
 202         int ret = 0;
 203         int i;
 204
 205         vgic_cpu->rd_iodev.base_addr = VGIC_ADDR_UNDEF;
 206         vgic_cpu->sgi_iodev.base_addr = VGIC_ADDR_UNDEF;
 207
 208         INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
 209         spin_lock_init(&vgic_cpu->ap_list_lock);
 210
 211         /*
 212          * Enable and configure all SGIs to be edge-triggered and
 213          * configure all PPIs as level-triggered.
 214          */
 215         for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
 216                 struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
 217
 218                 INIT_LIST_HEAD(&irq->ap_list);
 219                 spin_lock_init(&irq->irq_lock);
 220                 irq->intid = i;
 221                 irq->vcpu = NULL;
 222                 irq->target_vcpu = vcpu;
 223                 irq->targets = 1U << vcpu->vcpu_id;
 224                 kref_init(&irq->refcount);
 225                 if (vgic_irq_is_sgi(i)) {
 226                         /* SGIs */
 227                         irq->enabled = 1;
 228                         irq->config = VGIC_CONFIG_EDGE;
 229                 } else {
 230                         /* PPIs */
 231                         irq->config = VGIC_CONFIG_LEVEL;
 232                 }
 233
 234                 /*
 235                  * GICv3 can only be created via the KVM_DEVICE_CREATE API and
 236                  * so we always know the emulation type at this point as it's
 237                  * either explicitly configured as GICv3, or explicitly
 238                  * configured as GICv2, or not configured yet which also
 239                  * implies GICv2.
 240                  */
 241                 if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3)
 242                         irq->group = 1;
 243                 else
 244                         irq->group = 0;
 245         }
 246
 247         if (!irqchip_in_kernel(vcpu->kvm))
 248                 return 0;
 249
 250         /*
 251          * If we are creating a VCPU with a GICv3 we must also register the
 252          * KVM io device for the redistributor that belongs to this VCPU.
 253          */
 254         if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
 255                 mutex_lock(&vcpu->kvm->lock);
 256                 ret = vgic_register_redist_iodev(vcpu);
 257                 mutex_unlock(&vcpu->kvm->lock);
 258         }
 259         return ret;
 260 }
 261
 262 static void kvm_vgic_vcpu_enable(struct kvm_vcpu *vcpu)
 263 {
 264         if (kvm_vgic_global_state.type == VGIC_V2)
 265                 vgic_v2_enable(vcpu);
 266         else
 267                 vgic_v3_enable(vcpu);
 268 }
 269
 270 /*
 271  * vgic_init: allocates and initializes dist and vcpu data structures
 272  * depending on two dimensioning parameters:
 273  * - the number of spis
 274  * - the number of vcpus
 275  * The function is generally called when nr_spis has been explicitly set
 276  * by the guest through the KVM DEVICE API. If not nr_spis is set to 256.
 277  * vgic_initialized() returns true when this function has succeeded.
 278  * Must be called with kvm->lock held!
 279  */
 280 int vgic_init(struct kvm *kvm)
 281 {
 282         struct vgic_dist *dist = &kvm->arch.vgic;
 283         struct kvm_vcpu *vcpu;
 284         int ret = 0, i;
 285
 286         if (vgic_initialized(kvm))
 287                 return 0;
 288
 289         /* Are we also in the middle of creating a VCPU? */
 290         if (kvm->created_vcpus != atomic_read(&kvm->online_vcpus))
 291                 return -EBUSY;
 292
 293         /* freeze the number of spis */
 294         if (!dist->nr_spis)
 295                 dist->nr_spis = VGIC_NR_IRQS_LEGACY - VGIC_NR_PRIVATE_IRQS;
 296
 297         ret = kvm_vgic_dist_init(kvm, dist->nr_spis);
 298         if (ret)
 299                 goto out;
 300
 301         if (vgic_has_its(kvm)) {
 302                 ret = vgic_v4_init(kvm);
 303                 if (ret)
 304                         goto out;
 305         }
 306
 307         kvm_for_each_vcpu(i, vcpu, kvm)
 308                 kvm_vgic_vcpu_enable(vcpu);
 309
 310         ret = kvm_vgic_setup_default_irq_routing(kvm);
 311         if (ret)
 312                 goto out;
 313
 314         vgic_debug_init(kvm);
 315
 316         dist->implementation_rev = 2;
 317         dist->initialized = true;
 318
 319 out:
 320         return ret;
 321 }
 322
 323 static void kvm_vgic_dist_destroy(struct kvm *kvm)
 324 {
 325         struct vgic_dist *dist = &kvm->arch.vgic;
 326         struct vgic_redist_region *rdreg, *next;
 327
 328         dist->ready = false;
 329         dist->initialized = false;
 330
 331         kfree(dist->spis);
 332         dist->spis = NULL;
 333         dist->nr_spis = 0;
 334
 335         if (kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3) {
 336                 list_for_each_entry_safe(rdreg, next, &dist->rd_regions, list) {
 337                         list_del(&rdreg->list);
 338                         kfree(rdreg);
 339                 }
 340                 INIT_LIST_HEAD(&dist->rd_regions);
 341         }
 342
 343         if (vgic_supports_direct_msis(kvm))
 344                 vgic_v4_teardown(kvm);
 345 }
 346
 347 void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
 348 {
 349         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 350
 351         INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
 352 }
 353
 354 /* To be called with kvm->lock held */
 355 static void __kvm_vgic_destroy(struct kvm *kvm)
 356 {
 357         struct kvm_vcpu *vcpu;
 358         int i;
 359
 360         vgic_debug_destroy(kvm);
 361
 362         kvm_vgic_dist_destroy(kvm);
 363
 364         kvm_for_each_vcpu(i, vcpu, kvm)
 365                 kvm_vgic_vcpu_destroy(vcpu);
 366 }
 367
 368 void kvm_vgic_destroy(struct kvm *kvm)
 369 {
 370         mutex_lock(&kvm->lock);
 371         __kvm_vgic_destroy(kvm);
 372         mutex_unlock(&kvm->lock);
 373 }
 374
 375 /**
 376  * vgic_lazy_init: Lazy init is only allowed if the GIC exposed to the guest
 377  * is a GICv2. A GICv3 must be explicitly initialized by the guest using the
 378  * KVM_DEV_ARM_VGIC_GRP_CTRL KVM_DEVICE group.
 379  * @kvm: kvm struct pointer
 380  */
 381 int vgic_lazy_init(struct kvm *kvm)
 382 {
 383         int ret = 0;
 384
 385         if (unlikely(!vgic_initialized(kvm))) {
 386                 /*
 387                  * We only provide the automatic initialization of the VGIC
 388                  * for the legacy case of a GICv2. Any other type must
 389                  * be explicitly initialized once setup with the respective
 390                  * KVM device call.
 391                  */
 392                 if (kvm->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V2)
 393                         return -EBUSY;
 394
 395                 mutex_lock(&kvm->lock);
 396                 ret = vgic_init(kvm);
 397                 mutex_unlock(&kvm->lock);
 398         }
 399
 400         return ret;
 401 }
 402
 403 /* RESOURCE MAPPING */
 404
 405 /**
 406  * Map the MMIO regions depending on the VGIC model exposed to the guest
 407  * called on the first VCPU run.
 408  * Also map the virtual CPU interface into the VM.
 409  * v2/v3 derivatives call vgic_init if not already done.
 410  * vgic_ready() returns true if this function has succeeded.
 411  * @kvm: kvm struct pointer
 412  */
 413 int kvm_vgic_map_resources(struct kvm *kvm)
 414 {
 415         struct vgic_dist *dist = &kvm->arch.vgic;
 416         int ret = 0;
 417
 418         mutex_lock(&kvm->lock);
 419         if (!irqchip_in_kernel(kvm))
 420                 goto out;
 421
 422         if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
 423                 ret = vgic_v2_map_resources(kvm);
 424         else
 425                 ret = vgic_v3_map_resources(kvm);
 426
 427         if (ret)
 428                 __kvm_vgic_destroy(kvm);
 429
 430 out:
 431         mutex_unlock(&kvm->lock);
 432         return ret;
 433 }
 434
 435 /* GENERIC PROBE */
 436
 437 static int vgic_init_cpu_starting(unsigned int cpu)
 438 {
 439         enable_percpu_irq(kvm_vgic_global_state.maint_irq, 0);
 440         return 0;
 441 }
 442
 443
 444 static int vgic_init_cpu_dying(unsigned int cpu)
 445 {
 446         disable_percpu_irq(kvm_vgic_global_state.maint_irq);
 447         return 0;
 448 }
 449
 450 static irqreturn_t vgic_maintenance_handler(int irq, void *data)
 451 {
 452         /*
 453          * We cannot rely on the vgic maintenance interrupt to be
 454          * delivered synchronously. This means we can only use it to
 455          * exit the VM, and we perform the handling of EOIed
 456          * interrupts on the exit path (see vgic_fold_lr_state).
 457          */
 458         return IRQ_HANDLED;
 459 }
 460
 461 /**
 462  * kvm_vgic_init_cpu_hardware - initialize the GIC VE hardware
 463  *
 464  * For a specific CPU, initialize the GIC VE hardware.
 465  */
 466 void kvm_vgic_init_cpu_hardware(void)
 467 {
 468         BUG_ON(preemptible());
 469
 470         /*
 471          * We want to make sure the list registers start out clear so that we
 472          * only have the program the used registers.
 473          */
 474         if (kvm_vgic_global_state.type == VGIC_V2)
 475                 vgic_v2_init_lrs();
 476         else
 477                 kvm_call_hyp(__vgic_v3_init_lrs);
 478 }
 479
 480 /**
 481  * kvm_vgic_hyp_init: populates the kvm_vgic_global_state variable
 482  * according to the host GIC model. Accordingly calls either
 483  * vgic_v2/v3_probe which registers the KVM_DEVICE that can be
 484  * instantiated by a guest later on .
 485  */
 486 int kvm_vgic_hyp_init(void)
 487 {
 488         const struct gic_kvm_info *gic_kvm_info;
 489         int ret;
 490
 491         gic_kvm_info = gic_get_kvm_info();
 492         if (!gic_kvm_info)
 493                 return -ENODEV;
 494
 495         if (!gic_kvm_info->maint_irq) {
 496                 kvm_err("No vgic maintenance irq\n");
 497                 return -ENXIO;
 498         }
 499
 500         switch (gic_kvm_info->type) {
 501         case GIC_V2:
 502                 ret = vgic_v2_probe(gic_kvm_info);
 503                 break;
 504         case GIC_V3:
 505                 ret = vgic_v3_probe(gic_kvm_info);
 506                 if (!ret) {
 507                         static_branch_enable(&kvm_vgic_global_state.gicv3_cpuif);
 508                         kvm_info("GIC system register CPU interface enabled\n");
 509                 }
 510                 break;
 511         default:
 512                 ret = -ENODEV;
 513         };
 514
 515         if (ret)
 516                 return ret;
 517
 518         kvm_vgic_global_state.maint_irq = gic_kvm_info->maint_irq;
 519         ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,
 520                                  vgic_maintenance_handler,
 521                                  "vgic", kvm_get_running_vcpus());
 522         if (ret) {
 523                 kvm_err("Cannot register interrupt %d\n",
 524                         kvm_vgic_global_state.maint_irq);
 525                 return ret;
 526         }
 527
 528         ret = cpuhp_setup_state(CPUHP_AP_KVM_ARM_VGIC_INIT_STARTING,
 529                                 "kvm/arm/vgic:starting",
 530                                 vgic_init_cpu_starting, vgic_init_cpu_dying);
 531         if (ret) {
 532                 kvm_err("Cannot register vgic CPU notifier\n");
 533                 goto out_free_irq;
 534         }
 535
 536         kvm_info("vgic interrupt IRQ%d\n", kvm_vgic_global_state.maint_irq);
 537         return 0;
 538
 539 out_free_irq:
 540         free_percpu_irq(kvm_vgic_global_state.maint_irq,
 541                         kvm_get_running_vcpus());
 542         return ret;
 543 }