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_early_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 /**
  71  * kvm_vgic_vcpu_early_init() - Initialize static VGIC VCPU data structures
  72  * @vcpu: The VCPU whose VGIC data structures whould be initialized
  73  *
  74  * Only do initialization, but do not actually enable the VGIC CPU interface
  75  * yet.
  76  */
  77 void kvm_vgic_vcpu_early_init(struct kvm_vcpu *vcpu)
  78 {
  79         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
  80         int i;
  81
  82         INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
  83         spin_lock_init(&vgic_cpu->ap_list_lock);
  84
  85         /*
  86          * Enable and configure all SGIs to be edge-triggered and
  87          * configure all PPIs as level-triggered.
  88          */
  89         for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
  90                 struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
  91
  92                 INIT_LIST_HEAD(&irq->ap_list);
  93                 spin_lock_init(&irq->irq_lock);
  94                 irq->intid = i;
  95                 irq->vcpu = NULL;
  96                 irq->target_vcpu = vcpu;
  97                 irq->targets = 1U << vcpu->vcpu_id;
  98                 kref_init(&irq->refcount);
  99                 if (vgic_irq_is_sgi(i)) {
 100                         /* SGIs */
 101                         irq->enabled = 1;
 102                         irq->config = VGIC_CONFIG_EDGE;
 103                 } else {
 104                         /* PPIs */
 105                         irq->config = VGIC_CONFIG_LEVEL;
 106                 }
 107         }
 108 }
 109
 110 /* CREATION */
 111
 112 /**
 113  * kvm_vgic_create: triggered by the instantiation of the VGIC device by
 114  * user space, either through the legacy KVM_CREATE_IRQCHIP ioctl (v2 only)
 115  * or through the generic KVM_CREATE_DEVICE API ioctl.
 116  * irqchip_in_kernel() tells you if this function succeeded or not.
 117  * @kvm: kvm struct pointer
 118  * @type: KVM_DEV_TYPE_ARM_VGIC_V[23]
 119  */
 120 int kvm_vgic_create(struct kvm *kvm, u32 type)
 121 {
 122         int i, vcpu_lock_idx = -1, ret;
 123         struct kvm_vcpu *vcpu;
 124
 125         if (irqchip_in_kernel(kvm))
 126                 return -EEXIST;
 127
 128         /*
 129          * This function is also called by the KVM_CREATE_IRQCHIP handler,
 130          * which had no chance yet to check the availability of the GICv2
 131          * emulation. So check this here again. KVM_CREATE_DEVICE does
 132          * the proper checks already.
 133          */
 134         if (type == KVM_DEV_TYPE_ARM_VGIC_V2 &&
 135                 !kvm_vgic_global_state.can_emulate_gicv2)
 136                 return -ENODEV;
 137
 138         /*
 139          * Any time a vcpu is run, vcpu_load is called which tries to grab the
 140          * vcpu->mutex.  By grabbing the vcpu->mutex of all VCPUs we ensure
 141          * that no other VCPUs are run while we create the vgic.
 142          */
 143         ret = -EBUSY;
 144         kvm_for_each_vcpu(i, vcpu, kvm) {
 145                 if (!mutex_trylock(&vcpu->mutex))
 146                         goto out_unlock;
 147                 vcpu_lock_idx = i;
 148         }
 149
 150         kvm_for_each_vcpu(i, vcpu, kvm) {
 151                 if (vcpu->arch.has_run_once)
 152                         goto out_unlock;
 153         }
 154         ret = 0;
 155
 156         if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
 157                 kvm->arch.max_vcpus = VGIC_V2_MAX_CPUS;
 158         else
 159                 kvm->arch.max_vcpus = VGIC_V3_MAX_CPUS;
 160
 161         if (atomic_read(&kvm->online_vcpus) > kvm->arch.max_vcpus) {
 162                 ret = -E2BIG;
 163                 goto out_unlock;
 164         }
 165
 166         kvm->arch.vgic.in_kernel = true;
 167         kvm->arch.vgic.vgic_model = type;
 168
 169         /*
 170          * kvm_vgic_global_state.vctrl_base is set on vgic probe (kvm_arch_init)
 171          * it is stored in distributor struct for asm save/restore purpose
 172          */
 173         kvm->arch.vgic.vctrl_base = kvm_vgic_global_state.vctrl_base;
 174
 175         kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
 176         kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
 177         kvm->arch.vgic.vgic_redist_base = VGIC_ADDR_UNDEF;
 178
 179 out_unlock:
 180         for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
 181                 vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
 182                 mutex_unlock(&vcpu->mutex);
 183         }
 184         return ret;
 185 }
 186
 187 /* INIT/DESTROY */
 188
 189 /**
 190  * kvm_vgic_dist_init: initialize the dist data structures
 191  * @kvm: kvm struct pointer
 192  * @nr_spis: number of spis, frozen by caller
 193  */
 194 static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
 195 {
 196         struct vgic_dist *dist = &kvm->arch.vgic;
 197         struct kvm_vcpu *vcpu0 = kvm_get_vcpu(kvm, 0);
 198         int i;
 199
 200         dist->spis = kcalloc(nr_spis, sizeof(struct vgic_irq), GFP_KERNEL);
 201         if (!dist->spis)
 202                 return  -ENOMEM;
 203
 204         /*
 205          * In the following code we do not take the irq struct lock since
 206          * no other action on irq structs can happen while the VGIC is
 207          * not initialized yet:
 208          * If someone wants to inject an interrupt or does a MMIO access, we
 209          * require prior initialization in case of a virtual GICv3 or trigger
 210          * initialization when using a virtual GICv2.
 211          */
 212         for (i = 0; i < nr_spis; i++) {
 213                 struct vgic_irq *irq = &dist->spis[i];
 214
 215                 irq->intid = i + VGIC_NR_PRIVATE_IRQS;
 216                 INIT_LIST_HEAD(&irq->ap_list);
 217                 spin_lock_init(&irq->irq_lock);
 218                 irq->vcpu = NULL;
 219                 irq->target_vcpu = vcpu0;
 220                 kref_init(&irq->refcount);
 221                 if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
 222                         irq->targets = 0;
 223                 else
 224                         irq->mpidr = 0;
 225         }
 226         return 0;
 227 }
 228
 229 /**
 230  * kvm_vgic_vcpu_init() - Enable the VCPU interface
 231  * @vcpu: the VCPU which's VGIC should be enabled
 232  */
 233 static void kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
 234 {
 235         if (kvm_vgic_global_state.type == VGIC_V2)
 236                 vgic_v2_enable(vcpu);
 237         else
 238                 vgic_v3_enable(vcpu);
 239 }
 240
 241 /*
 242  * vgic_init: allocates and initializes dist and vcpu data structures
 243  * depending on two dimensioning parameters:
 244  * - the number of spis
 245  * - the number of vcpus
 246  * The function is generally called when nr_spis has been explicitly set
 247  * by the guest through the KVM DEVICE API. If not nr_spis is set to 256.
 248  * vgic_initialized() returns true when this function has succeeded.
 249  * Must be called with kvm->lock held!
 250  */
 251 int vgic_init(struct kvm *kvm)
 252 {
 253         struct vgic_dist *dist = &kvm->arch.vgic;
 254         struct kvm_vcpu *vcpu;
 255         int ret = 0, i;
 256
 257         if (vgic_initialized(kvm))
 258                 return 0;
 259
 260         /* freeze the number of spis */
 261         if (!dist->nr_spis)
 262                 dist->nr_spis = VGIC_NR_IRQS_LEGACY - VGIC_NR_PRIVATE_IRQS;
 263
 264         ret = kvm_vgic_dist_init(kvm, dist->nr_spis);
 265         if (ret)
 266                 goto out;
 267
 268         if (vgic_has_its(kvm))
 269                 dist->msis_require_devid = true;
 270
 271         kvm_for_each_vcpu(i, vcpu, kvm)
 272                 kvm_vgic_vcpu_init(vcpu);
 273
 274         ret = kvm_vgic_setup_default_irq_routing(kvm);
 275         if (ret)
 276                 goto out;
 277
 278         vgic_debug_init(kvm);
 279
 280         dist->initialized = true;
 281
 282         /*
 283          * If we're initializing GICv2 on-demand when first running the VCPU
 284          * then we need to load the VGIC state onto the CPU.  We can detect
 285          * this easily by checking if we are in between vcpu_load and vcpu_put
 286          * when we just initialized the VGIC.
 287          */
 288         preempt_disable();
 289         vcpu = kvm_arm_get_running_vcpu();
 290         if (vcpu)
 291                 kvm_vgic_load(vcpu);
 292         preempt_enable();
 293 out:
 294         return ret;
 295 }
 296
 297 static void kvm_vgic_dist_destroy(struct kvm *kvm)
 298 {
 299         struct vgic_dist *dist = &kvm->arch.vgic;
 300
 301         dist->ready = false;
 302         dist->initialized = false;
 303
 304         kfree(dist->spis);
 305         dist->nr_spis = 0;
 306 }
 307
 308 void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
 309 {
 310         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 311
 312         INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
 313 }
 314
 315 /* To be called with kvm->lock held */
 316 static void __kvm_vgic_destroy(struct kvm *kvm)
 317 {
 318         struct kvm_vcpu *vcpu;
 319         int i;
 320
 321         vgic_debug_destroy(kvm);
 322
 323         kvm_vgic_dist_destroy(kvm);
 324
 325         kvm_for_each_vcpu(i, vcpu, kvm)
 326                 kvm_vgic_vcpu_destroy(vcpu);
 327 }
 328
 329 void kvm_vgic_destroy(struct kvm *kvm)
 330 {
 331         mutex_lock(&kvm->lock);
 332         __kvm_vgic_destroy(kvm);
 333         mutex_unlock(&kvm->lock);
 334 }
 335
 336 /**
 337  * vgic_lazy_init: Lazy init is only allowed if the GIC exposed to the guest
 338  * is a GICv2. A GICv3 must be explicitly initialized by the guest using the
 339  * KVM_DEV_ARM_VGIC_GRP_CTRL KVM_DEVICE group.
 340  * @kvm: kvm struct pointer
 341  */
 342 int vgic_lazy_init(struct kvm *kvm)
 343 {
 344         int ret = 0;
 345
 346         if (unlikely(!vgic_initialized(kvm))) {
 347                 /*
 348                  * We only provide the automatic initialization of the VGIC
 349                  * for the legacy case of a GICv2. Any other type must
 350                  * be explicitly initialized once setup with the respective
 351                  * KVM device call.
 352                  */
 353                 if (kvm->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V2)
 354                         return -EBUSY;
 355
 356                 mutex_lock(&kvm->lock);
 357                 ret = vgic_init(kvm);
 358                 mutex_unlock(&kvm->lock);
 359         }
 360
 361         return ret;
 362 }
 363
 364 /* RESOURCE MAPPING */
 365
 366 /**
 367  * Map the MMIO regions depending on the VGIC model exposed to the guest
 368  * called on the first VCPU run.
 369  * Also map the virtual CPU interface into the VM.
 370  * v2/v3 derivatives call vgic_init if not already done.
 371  * vgic_ready() returns true if this function has succeeded.
 372  * @kvm: kvm struct pointer
 373  */
 374 int kvm_vgic_map_resources(struct kvm *kvm)
 375 {
 376         struct vgic_dist *dist = &kvm->arch.vgic;
 377         int ret = 0;
 378
 379         mutex_lock(&kvm->lock);
 380         if (!irqchip_in_kernel(kvm))
 381                 goto out;
 382
 383         if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
 384                 ret = vgic_v2_map_resources(kvm);
 385         else
 386                 ret = vgic_v3_map_resources(kvm);
 387
 388         if (ret)
 389                 __kvm_vgic_destroy(kvm);
 390
 391 out:
 392         mutex_unlock(&kvm->lock);
 393         return ret;
 394 }
 395
 396 /* GENERIC PROBE */
 397
 398 static int vgic_init_cpu_starting(unsigned int cpu)
 399 {
 400         enable_percpu_irq(kvm_vgic_global_state.maint_irq, 0);
 401         return 0;
 402 }
 403
 404
 405 static int vgic_init_cpu_dying(unsigned int cpu)
 406 {
 407         disable_percpu_irq(kvm_vgic_global_state.maint_irq);
 408         return 0;
 409 }
 410
 411 static irqreturn_t vgic_maintenance_handler(int irq, void *data)
 412 {
 413         /*
 414          * We cannot rely on the vgic maintenance interrupt to be
 415          * delivered synchronously. This means we can only use it to
 416          * exit the VM, and we perform the handling of EOIed
 417          * interrupts on the exit path (see vgic_process_maintenance).
 418          */
 419         return IRQ_HANDLED;
 420 }
 421
 422 /**
 423  * kvm_vgic_init_cpu_hardware - initialize the GIC VE hardware
 424  *
 425  * For a specific CPU, initialize the GIC VE hardware.
 426  */
 427 void kvm_vgic_init_cpu_hardware(void)
 428 {
 429         BUG_ON(preemptible());
 430
 431         /*
 432          * We want to make sure the list registers start out clear so that we
 433          * only have the program the used registers.
 434          */
 435         if (kvm_vgic_global_state.type == VGIC_V2)
 436                 vgic_v2_init_lrs();
 437         else
 438                 kvm_call_hyp(__vgic_v3_init_lrs);
 439 }
 440
 441 /**
 442  * kvm_vgic_hyp_init: populates the kvm_vgic_global_state variable
 443  * according to the host GIC model. Accordingly calls either
 444  * vgic_v2/v3_probe which registers the KVM_DEVICE that can be
 445  * instantiated by a guest later on .
 446  */
 447 int kvm_vgic_hyp_init(void)
 448 {
 449         const struct gic_kvm_info *gic_kvm_info;
 450         int ret;
 451
 452         gic_kvm_info = gic_get_kvm_info();
 453         if (!gic_kvm_info)
 454                 return -ENODEV;
 455
 456         if (!gic_kvm_info->maint_irq) {
 457                 kvm_err("No vgic maintenance irq\n");
 458                 return -ENXIO;
 459         }
 460
 461         switch (gic_kvm_info->type) {
 462         case GIC_V2:
 463                 ret = vgic_v2_probe(gic_kvm_info);
 464                 break;
 465         case GIC_V3:
 466                 ret = vgic_v3_probe(gic_kvm_info);
 467                 if (!ret) {
 468                         static_branch_enable(&kvm_vgic_global_state.gicv3_cpuif);
 469                         kvm_info("GIC system register CPU interface enabled\n");
 470                 }
 471                 break;
 472         default:
 473                 ret = -ENODEV;
 474         };
 475
 476         if (ret)
 477                 return ret;
 478
 479         kvm_vgic_global_state.maint_irq = gic_kvm_info->maint_irq;
 480         ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,
 481                                  vgic_maintenance_handler,
 482                                  "vgic", kvm_get_running_vcpus());
 483         if (ret) {
 484                 kvm_err("Cannot register interrupt %d\n",
 485                         kvm_vgic_global_state.maint_irq);
 486                 return ret;
 487         }
 488
 489         ret = cpuhp_setup_state(CPUHP_AP_KVM_ARM_VGIC_INIT_STARTING,
 490                                 "kvm/arm/vgic:starting",
 491                                 vgic_init_cpu_starting, vgic_init_cpu_dying);
 492         if (ret) {
 493                 kvm_err("Cannot register vgic CPU notifier\n");
 494                 goto out_free_irq;
 495         }
 496
 497         kvm_info("vgic interrupt IRQ%d\n", kvm_vgic_global_state.maint_irq);
 498         return 0;
 499
 500 out_free_irq:
 501         free_percpu_irq(kvm_vgic_global_state.maint_irq,
 502                         kvm_get_running_vcpus());
 503         return ret;
 504 }