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.
  28  *
  29  * Distributor:
  30  *
  31  * - kvm_vgic_early_init(): initialization of static data that doesn't
  32  *   depend on any sizing information or emulation type. No allocation
  33  *   is allowed there.
  34  *
  35  * - vgic_init(): allocation and initialization of the generic data
  36  *   structures that depend on sizing information (number of CPUs,
  37  *   number of interrupts). Also initializes the vcpu specific data
  38  *   structures. Can be executed lazily for GICv2.
  39  *
  40  * CPU Interface:
  41  *
  42  * - kvm_vgic_cpu_early_init(): initialization of static data that
  43  *   doesn't depend on any sizing information or emulation type. No
  44  *   allocation is allowed there.
  45  */
  46
  47 /* EARLY INIT */
  48
  49 /*
  50  * Those 2 functions should not be needed anymore but they
  51  * still are called from arm.c
  52  */
  53 void kvm_vgic_early_init(struct kvm *kvm)
  54 {
  55 }
  56
  57 void kvm_vgic_vcpu_early_init(struct kvm_vcpu *vcpu)
  58 {
  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         mutex_lock(&kvm->lock);
  77
  78         if (irqchip_in_kernel(kvm)) {
  79                 ret = -EEXIST;
  80                 goto out;
  81         }
  82
  83         /*
  84          * This function is also called by the KVM_CREATE_IRQCHIP handler,
  85          * which had no chance yet to check the availability of the GICv2
  86          * emulation. So check this here again. KVM_CREATE_DEVICE does
  87          * the proper checks already.
  88          */
  89         if (type == KVM_DEV_TYPE_ARM_VGIC_V2 &&
  90                 !kvm_vgic_global_state.can_emulate_gicv2) {
  91                 ret = -ENODEV;
  92                 goto out;
  93         }
  94
  95         /*
  96          * Any time a vcpu is run, vcpu_load is called which tries to grab the
  97          * vcpu->mutex.  By grabbing the vcpu->mutex of all VCPUs we ensure
  98          * that no other VCPUs are run while we create the vgic.
  99          */
 100         ret = -EBUSY;
 101         kvm_for_each_vcpu(i, vcpu, kvm) {
 102                 if (!mutex_trylock(&vcpu->mutex))
 103                         goto out_unlock;
 104                 vcpu_lock_idx = i;
 105         }
 106
 107         kvm_for_each_vcpu(i, vcpu, kvm) {
 108                 if (vcpu->arch.has_run_once)
 109                         goto out_unlock;
 110         }
 111         ret = 0;
 112
 113         if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
 114                 kvm->arch.max_vcpus = VGIC_V2_MAX_CPUS;
 115         else
 116                 kvm->arch.max_vcpus = VGIC_V3_MAX_CPUS;
 117
 118         if (atomic_read(&kvm->online_vcpus) > kvm->arch.max_vcpus) {
 119                 ret = -E2BIG;
 120                 goto out_unlock;
 121         }
 122
 123         kvm->arch.vgic.in_kernel = true;
 124         kvm->arch.vgic.vgic_model = type;
 125
 126         /*
 127          * kvm_vgic_global_state.vctrl_base is set on vgic probe (kvm_arch_init)
 128          * it is stored in distributor struct for asm save/restore purpose
 129          */
 130         kvm->arch.vgic.vctrl_base = kvm_vgic_global_state.vctrl_base;
 131
 132         kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
 133         kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
 134         kvm->arch.vgic.vgic_redist_base = VGIC_ADDR_UNDEF;
 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
 142 out:
 143         mutex_unlock(&kvm->lock);
 144         return ret;
 145 }
 146
 147 /* INIT/DESTROY */
 148
 149 /**
 150  * kvm_vgic_dist_init: initialize the dist data structures
 151  * @kvm: kvm struct pointer
 152  * @nr_spis: number of spis, frozen by caller
 153  */
 154 static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
 155 {
 156         struct vgic_dist *dist = &kvm->arch.vgic;
 157         struct kvm_vcpu *vcpu0 = kvm_get_vcpu(kvm, 0);
 158         int i;
 159
 160         INIT_LIST_HEAD(&dist->lpi_list_head);
 161         spin_lock_init(&dist->lpi_list_lock);
 162
 163         dist->spis = kcalloc(nr_spis, sizeof(struct vgic_irq), GFP_KERNEL);
 164         if (!dist->spis)
 165                 return  -ENOMEM;
 166
 167         /*
 168          * In the following code we do not take the irq struct lock since
 169          * no other action on irq structs can happen while the VGIC is
 170          * not initialized yet:
 171          * If someone wants to inject an interrupt or does a MMIO access, we
 172          * require prior initialization in case of a virtual GICv3 or trigger
 173          * initialization when using a virtual GICv2.
 174          */
 175         for (i = 0; i < nr_spis; i++) {
 176                 struct vgic_irq *irq = &dist->spis[i];
 177
 178                 irq->intid = i + VGIC_NR_PRIVATE_IRQS;
 179                 INIT_LIST_HEAD(&irq->ap_list);
 180                 spin_lock_init(&irq->irq_lock);
 181                 irq->vcpu = NULL;
 182                 irq->target_vcpu = vcpu0;
 183                 kref_init(&irq->refcount);
 184                 if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
 185                         irq->targets = 0;
 186                 else
 187                         irq->mpidr = 0;
 188         }
 189         return 0;
 190 }
 191
 192 /**
 193  * kvm_vgic_vcpu_init: initialize the vcpu data structures and
 194  * enable the VCPU interface
 195  * @vcpu: the VCPU which's VGIC should be initialized
 196  */
 197 static void kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
 198 {
 199         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 200         int i;
 201
 202         INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
 203         spin_lock_init(&vgic_cpu->ap_list_lock);
 204
 205         /*
 206          * Enable and configure all SGIs to be edge-triggered and
 207          * configure all PPIs as level-triggered.
 208          */
 209         for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
 210                 struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
 211
 212                 INIT_LIST_HEAD(&irq->ap_list);
 213                 spin_lock_init(&irq->irq_lock);
 214                 irq->intid = i;
 215                 irq->vcpu = NULL;
 216                 irq->target_vcpu = vcpu;
 217                 irq->targets = 1U << vcpu->vcpu_id;
 218                 kref_init(&irq->refcount);
 219                 if (vgic_irq_is_sgi(i)) {
 220                         /* SGIs */
 221                         irq->enabled = 1;
 222                         irq->config = VGIC_CONFIG_EDGE;
 223                 } else {
 224                         /* PPIs */
 225                         irq->config = VGIC_CONFIG_LEVEL;
 226                 }
 227         }
 228         if (kvm_vgic_global_state.type == VGIC_V2)
 229                 vgic_v2_enable(vcpu);
 230         else
 231                 vgic_v3_enable(vcpu);
 232 }
 233
 234 /*
 235  * vgic_init: allocates and initializes dist and vcpu data structures
 236  * depending on two dimensioning parameters:
 237  * - the number of spis
 238  * - the number of vcpus
 239  * The function is generally called when nr_spis has been explicitly set
 240  * by the guest through the KVM DEVICE API. If not nr_spis is set to 256.
 241  * vgic_initialized() returns true when this function has succeeded.
 242  * Must be called with kvm->lock held!
 243  */
 244 int vgic_init(struct kvm *kvm)
 245 {
 246         struct vgic_dist *dist = &kvm->arch.vgic;
 247         struct kvm_vcpu *vcpu;
 248         int ret = 0, i;
 249
 250         if (vgic_initialized(kvm))
 251                 return 0;
 252
 253         /* freeze the number of spis */
 254         if (!dist->nr_spis)
 255                 dist->nr_spis = VGIC_NR_IRQS_LEGACY - VGIC_NR_PRIVATE_IRQS;
 256
 257         ret = kvm_vgic_dist_init(kvm, dist->nr_spis);
 258         if (ret)
 259                 goto out;
 260
 261         if (vgic_has_its(kvm))
 262                 dist->msis_require_devid = true;
 263
 264         kvm_for_each_vcpu(i, vcpu, kvm)
 265                 kvm_vgic_vcpu_init(vcpu);
 266
 267         ret = kvm_vgic_setup_default_irq_routing(kvm);
 268         if (ret)
 269                 goto out;
 270
 271         dist->initialized = true;
 272 out:
 273         return ret;
 274 }
 275
 276 static void kvm_vgic_dist_destroy(struct kvm *kvm)
 277 {
 278         struct vgic_dist *dist = &kvm->arch.vgic;
 279
 280         mutex_lock(&kvm->lock);
 281
 282         dist->ready = false;
 283         dist->initialized = false;
 284
 285         kfree(dist->spis);
 286         dist->nr_spis = 0;
 287
 288         mutex_unlock(&kvm->lock);
 289 }
 290
 291 void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
 292 {
 293         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 294
 295         INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
 296 }
 297
 298 void kvm_vgic_destroy(struct kvm *kvm)
 299 {
 300         struct kvm_vcpu *vcpu;
 301         int i;
 302
 303         kvm_vgic_dist_destroy(kvm);
 304
 305         kvm_for_each_vcpu(i, vcpu, kvm)
 306                 kvm_vgic_vcpu_destroy(vcpu);
 307 }
 308
 309 /**
 310  * vgic_lazy_init: Lazy init is only allowed if the GIC exposed to the guest
 311  * is a GICv2. A GICv3 must be explicitly initialized by the guest using the
 312  * KVM_DEV_ARM_VGIC_GRP_CTRL KVM_DEVICE group.
 313  * @kvm: kvm struct pointer
 314  */
 315 int vgic_lazy_init(struct kvm *kvm)
 316 {
 317         int ret = 0;
 318
 319         if (unlikely(!vgic_initialized(kvm))) {
 320                 /*
 321                  * We only provide the automatic initialization of the VGIC
 322                  * for the legacy case of a GICv2. Any other type must
 323                  * be explicitly initialized once setup with the respective
 324                  * KVM device call.
 325                  */
 326                 if (kvm->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V2)
 327                         return -EBUSY;
 328
 329                 mutex_lock(&kvm->lock);
 330                 ret = vgic_init(kvm);
 331                 mutex_unlock(&kvm->lock);
 332         }
 333
 334         return ret;
 335 }
 336
 337 /* RESOURCE MAPPING */
 338
 339 /**
 340  * Map the MMIO regions depending on the VGIC model exposed to the guest
 341  * called on the first VCPU run.
 342  * Also map the virtual CPU interface into the VM.
 343  * v2/v3 derivatives call vgic_init if not already done.
 344  * vgic_ready() returns true if this function has succeeded.
 345  * @kvm: kvm struct pointer
 346  */
 347 int kvm_vgic_map_resources(struct kvm *kvm)
 348 {
 349         struct vgic_dist *dist = &kvm->arch.vgic;
 350         int ret = 0;
 351
 352         mutex_lock(&kvm->lock);
 353         if (!irqchip_in_kernel(kvm))
 354                 goto out;
 355
 356         if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
 357                 ret = vgic_v2_map_resources(kvm);
 358         else
 359                 ret = vgic_v3_map_resources(kvm);
 360 out:
 361         mutex_unlock(&kvm->lock);
 362         return ret;
 363 }
 364
 365 /* GENERIC PROBE */
 366
 367 static int vgic_init_cpu_starting(unsigned int cpu)
 368 {
 369         enable_percpu_irq(kvm_vgic_global_state.maint_irq, 0);
 370         return 0;
 371 }
 372
 373
 374 static int vgic_init_cpu_dying(unsigned int cpu)
 375 {
 376         disable_percpu_irq(kvm_vgic_global_state.maint_irq);
 377         return 0;
 378 }
 379
 380 static irqreturn_t vgic_maintenance_handler(int irq, void *data)
 381 {
 382         /*
 383          * We cannot rely on the vgic maintenance interrupt to be
 384          * delivered synchronously. This means we can only use it to
 385          * exit the VM, and we perform the handling of EOIed
 386          * interrupts on the exit path (see vgic_process_maintenance).
 387          */
 388         return IRQ_HANDLED;
 389 }
 390
 391 /**
 392  * kvm_vgic_hyp_init: populates the kvm_vgic_global_state variable
 393  * according to the host GIC model. Accordingly calls either
 394  * vgic_v2/v3_probe which registers the KVM_DEVICE that can be
 395  * instantiated by a guest later on .
 396  */
 397 int kvm_vgic_hyp_init(void)
 398 {
 399         const struct gic_kvm_info *gic_kvm_info;
 400         int ret;
 401
 402         gic_kvm_info = gic_get_kvm_info();
 403         if (!gic_kvm_info)
 404                 return -ENODEV;
 405
 406         if (!gic_kvm_info->maint_irq) {
 407                 kvm_err("No vgic maintenance irq\n");
 408                 return -ENXIO;
 409         }
 410
 411         switch (gic_kvm_info->type) {
 412         case GIC_V2:
 413                 ret = vgic_v2_probe(gic_kvm_info);
 414                 break;
 415         case GIC_V3:
 416                 ret = vgic_v3_probe(gic_kvm_info);
 417                 break;
 418         default:
 419                 ret = -ENODEV;
 420         };
 421
 422         if (ret)
 423                 return ret;
 424
 425         kvm_vgic_global_state.maint_irq = gic_kvm_info->maint_irq;
 426         ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,
 427                                  vgic_maintenance_handler,
 428                                  "vgic", kvm_get_running_vcpus());
 429         if (ret) {
 430                 kvm_err("Cannot register interrupt %d\n",
 431                         kvm_vgic_global_state.maint_irq);
 432                 return ret;
 433         }
 434
 435         ret = cpuhp_setup_state(CPUHP_AP_KVM_ARM_VGIC_INIT_STARTING,
 436                                 "AP_KVM_ARM_VGIC_INIT_STARTING",
 437                                 vgic_init_cpu_starting, vgic_init_cpu_dying);
 438         if (ret) {
 439                 kvm_err("Cannot register vgic CPU notifier\n");
 440                 goto out_free_irq;
 441         }
 442
 443         kvm_info("vgic interrupt IRQ%d\n", kvm_vgic_global_state.maint_irq);
 444         return 0;
 445
 446 out_free_irq:
 447         free_percpu_irq(kvm_vgic_global_state.maint_irq,
 448                         kvm_get_running_vcpus());
 449         return ret;
 450 }