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         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         /*
 121          * kvm_vgic_global_state.vctrl_base is set on vgic probe (kvm_arch_init)
 122          * it is stored in distributor struct for asm save/restore purpose
 123          */
 124         kvm->arch.vgic.vctrl_base = kvm_vgic_global_state.vctrl_base;
 125
 126         kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
 127         kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
 128         kvm->arch.vgic.vgic_redist_base = VGIC_ADDR_UNDEF;
 129
 130 out_unlock:
 131         for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
 132                 vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
 133                 mutex_unlock(&vcpu->mutex);
 134         }
 135         return ret;
 136 }
 137
 138 /* INIT/DESTROY */
 139
 140 /**
 141  * kvm_vgic_dist_init: initialize the dist data structures
 142  * @kvm: kvm struct pointer
 143  * @nr_spis: number of spis, frozen by caller
 144  */
 145 static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
 146 {
 147         struct vgic_dist *dist = &kvm->arch.vgic;
 148         struct kvm_vcpu *vcpu0 = kvm_get_vcpu(kvm, 0);
 149         int i;
 150
 151         INIT_LIST_HEAD(&dist->lpi_list_head);
 152         spin_lock_init(&dist->lpi_list_lock);
 153
 154         dist->spis = kcalloc(nr_spis, sizeof(struct vgic_irq), GFP_KERNEL);
 155         if (!dist->spis)
 156                 return  -ENOMEM;
 157
 158         /*
 159          * In the following code we do not take the irq struct lock since
 160          * no other action on irq structs can happen while the VGIC is
 161          * not initialized yet:
 162          * If someone wants to inject an interrupt or does a MMIO access, we
 163          * require prior initialization in case of a virtual GICv3 or trigger
 164          * initialization when using a virtual GICv2.
 165          */
 166         for (i = 0; i < nr_spis; i++) {
 167                 struct vgic_irq *irq = &dist->spis[i];
 168
 169                 irq->intid = i + VGIC_NR_PRIVATE_IRQS;
 170                 INIT_LIST_HEAD(&irq->ap_list);
 171                 spin_lock_init(&irq->irq_lock);
 172                 irq->vcpu = NULL;
 173                 irq->target_vcpu = vcpu0;
 174                 kref_init(&irq->refcount);
 175                 if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
 176                         irq->targets = 0;
 177                 else
 178                         irq->mpidr = 0;
 179         }
 180         return 0;
 181 }
 182
 183 /**
 184  * kvm_vgic_vcpu_init: initialize the vcpu data structures and
 185  * enable the VCPU interface
 186  * @vcpu: the VCPU which's VGIC should be initialized
 187  */
 188 static void kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
 189 {
 190         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 191         int i;
 192
 193         INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
 194         spin_lock_init(&vgic_cpu->ap_list_lock);
 195
 196         /*
 197          * Enable and configure all SGIs to be edge-triggered and
 198          * configure all PPIs as level-triggered.
 199          */
 200         for (i = 0; i < VGIC_NR_PRIVATE_IRQS; i++) {
 201                 struct vgic_irq *irq = &vgic_cpu->private_irqs[i];
 202
 203                 INIT_LIST_HEAD(&irq->ap_list);
 204                 spin_lock_init(&irq->irq_lock);
 205                 irq->intid = i;
 206                 irq->vcpu = NULL;
 207                 irq->target_vcpu = vcpu;
 208                 irq->targets = 1U << vcpu->vcpu_id;
 209                 kref_init(&irq->refcount);
 210                 if (vgic_irq_is_sgi(i)) {
 211                         /* SGIs */
 212                         irq->enabled = 1;
 213                         irq->config = VGIC_CONFIG_EDGE;
 214                 } else {
 215                         /* PPIs */
 216                         irq->config = VGIC_CONFIG_LEVEL;
 217                 }
 218         }
 219         if (kvm_vgic_global_state.type == VGIC_V2)
 220                 vgic_v2_enable(vcpu);
 221         else
 222                 vgic_v3_enable(vcpu);
 223 }
 224
 225 /*
 226  * vgic_init: allocates and initializes dist and vcpu data structures
 227  * depending on two dimensioning parameters:
 228  * - the number of spis
 229  * - the number of vcpus
 230  * The function is generally called when nr_spis has been explicitly set
 231  * by the guest through the KVM DEVICE API. If not nr_spis is set to 256.
 232  * vgic_initialized() returns true when this function has succeeded.
 233  * Must be called with kvm->lock held!
 234  */
 235 int vgic_init(struct kvm *kvm)
 236 {
 237         struct vgic_dist *dist = &kvm->arch.vgic;
 238         struct kvm_vcpu *vcpu;
 239         int ret = 0, i;
 240
 241         if (vgic_initialized(kvm))
 242                 return 0;
 243
 244         /* Are we also in the middle of creating a VCPU? */
 245         if (kvm->created_vcpus != atomic_read(&kvm->online_vcpus))
 246                 return -EBUSY;
 247
 248         /* freeze the number of spis */
 249         if (!dist->nr_spis)
 250                 dist->nr_spis = VGIC_NR_IRQS_LEGACY - VGIC_NR_PRIVATE_IRQS;
 251
 252         ret = kvm_vgic_dist_init(kvm, dist->nr_spis);
 253         if (ret)
 254                 goto out;
 255
 256         if (vgic_has_its(kvm))
 257                 dist->msis_require_devid = true;
 258
 259         kvm_for_each_vcpu(i, vcpu, kvm)
 260                 kvm_vgic_vcpu_init(vcpu);
 261
 262         ret = kvm_vgic_setup_default_irq_routing(kvm);
 263         if (ret)
 264                 goto out;
 265
 266         dist->initialized = true;
 267 out:
 268         return ret;
 269 }
 270
 271 static void kvm_vgic_dist_destroy(struct kvm *kvm)
 272 {
 273         struct vgic_dist *dist = &kvm->arch.vgic;
 274
 275         dist->ready = false;
 276         dist->initialized = false;
 277
 278         kfree(dist->spis);
 279         dist->nr_spis = 0;
 280 }
 281
 282 void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
 283 {
 284         struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
 285
 286         INIT_LIST_HEAD(&vgic_cpu->ap_list_head);
 287 }
 288
 289 /* To be called with kvm->lock held */
 290 static void __kvm_vgic_destroy(struct kvm *kvm)
 291 {
 292         struct kvm_vcpu *vcpu;
 293         int i;
 294
 295         kvm_vgic_dist_destroy(kvm);
 296
 297         kvm_for_each_vcpu(i, vcpu, kvm)
 298                 kvm_vgic_vcpu_destroy(vcpu);
 299 }
 300
 301 void kvm_vgic_destroy(struct kvm *kvm)
 302 {
 303         mutex_lock(&kvm->lock);
 304         __kvm_vgic_destroy(kvm);
 305         mutex_unlock(&kvm->lock);
 306 }
 307
 308 /**
 309  * vgic_lazy_init: Lazy init is only allowed if the GIC exposed to the guest
 310  * is a GICv2. A GICv3 must be explicitly initialized by the guest using the
 311  * KVM_DEV_ARM_VGIC_GRP_CTRL KVM_DEVICE group.
 312  * @kvm: kvm struct pointer
 313  */
 314 int vgic_lazy_init(struct kvm *kvm)
 315 {
 316         int ret = 0;
 317
 318         if (unlikely(!vgic_initialized(kvm))) {
 319                 /*
 320                  * We only provide the automatic initialization of the VGIC
 321                  * for the legacy case of a GICv2. Any other type must
 322                  * be explicitly initialized once setup with the respective
 323                  * KVM device call.
 324                  */
 325                 if (kvm->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V2)
 326                         return -EBUSY;
 327
 328                 mutex_lock(&kvm->lock);
 329                 ret = vgic_init(kvm);
 330                 mutex_unlock(&kvm->lock);
 331         }
 332
 333         return ret;
 334 }
 335
 336 /* RESOURCE MAPPING */
 337
 338 /**
 339  * Map the MMIO regions depending on the VGIC model exposed to the guest
 340  * called on the first VCPU run.
 341  * Also map the virtual CPU interface into the VM.
 342  * v2/v3 derivatives call vgic_init if not already done.
 343  * vgic_ready() returns true if this function has succeeded.
 344  * @kvm: kvm struct pointer
 345  */
 346 int kvm_vgic_map_resources(struct kvm *kvm)
 347 {
 348         struct vgic_dist *dist = &kvm->arch.vgic;
 349         int ret = 0;
 350
 351         mutex_lock(&kvm->lock);
 352         if (!irqchip_in_kernel(kvm))
 353                 goto out;
 354
 355         if (dist->vgic_model == KVM_DEV_TYPE_ARM_VGIC_V2)
 356                 ret = vgic_v2_map_resources(kvm);
 357         else
 358                 ret = vgic_v3_map_resources(kvm);
 359
 360         if (ret)
 361                 __kvm_vgic_destroy(kvm);
 362
 363 out:
 364         mutex_unlock(&kvm->lock);
 365         return ret;
 366 }
 367
 368 /* GENERIC PROBE */
 369
 370 static int vgic_init_cpu_starting(unsigned int cpu)
 371 {
 372         enable_percpu_irq(kvm_vgic_global_state.maint_irq, 0);
 373         return 0;
 374 }
 375
 376
 377 static int vgic_init_cpu_dying(unsigned int cpu)
 378 {
 379         disable_percpu_irq(kvm_vgic_global_state.maint_irq);
 380         return 0;
 381 }
 382
 383 static irqreturn_t vgic_maintenance_handler(int irq, void *data)
 384 {
 385         /*
 386          * We cannot rely on the vgic maintenance interrupt to be
 387          * delivered synchronously. This means we can only use it to
 388          * exit the VM, and we perform the handling of EOIed
 389          * interrupts on the exit path (see vgic_process_maintenance).
 390          */
 391         return IRQ_HANDLED;
 392 }
 393
 394 /**
 395  * kvm_vgic_hyp_init: populates the kvm_vgic_global_state variable
 396  * according to the host GIC model. Accordingly calls either
 397  * vgic_v2/v3_probe which registers the KVM_DEVICE that can be
 398  * instantiated by a guest later on .
 399  */
 400 int kvm_vgic_hyp_init(void)
 401 {
 402         const struct gic_kvm_info *gic_kvm_info;
 403         int ret;
 404
 405         gic_kvm_info = gic_get_kvm_info();
 406         if (!gic_kvm_info)
 407                 return -ENODEV;
 408
 409         if (!gic_kvm_info->maint_irq) {
 410                 kvm_err("No vgic maintenance irq\n");
 411                 return -ENXIO;
 412         }
 413
 414         switch (gic_kvm_info->type) {
 415         case GIC_V2:
 416                 ret = vgic_v2_probe(gic_kvm_info);
 417                 break;
 418         case GIC_V3:
 419                 ret = vgic_v3_probe(gic_kvm_info);
 420                 if (!ret) {
 421                         static_branch_enable(&kvm_vgic_global_state.gicv3_cpuif);
 422                         kvm_info("GIC system register CPU interface enabled\n");
 423                 }
 424                 break;
 425         default:
 426                 ret = -ENODEV;
 427         };
 428
 429         if (ret)
 430                 return ret;
 431
 432         kvm_vgic_global_state.maint_irq = gic_kvm_info->maint_irq;
 433         ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,
 434                                  vgic_maintenance_handler,
 435                                  "vgic", kvm_get_running_vcpus());
 436         if (ret) {
 437                 kvm_err("Cannot register interrupt %d\n",
 438                         kvm_vgic_global_state.maint_irq);
 439                 return ret;
 440         }
 441
 442         ret = cpuhp_setup_state(CPUHP_AP_KVM_ARM_VGIC_INIT_STARTING,
 443                                 "AP_KVM_ARM_VGIC_INIT_STARTING",
 444                                 vgic_init_cpu_starting, vgic_init_cpu_dying);
 445         if (ret) {
 446                 kvm_err("Cannot register vgic CPU notifier\n");
 447                 goto out_free_irq;
 448         }
 449
 450         kvm_info("vgic interrupt IRQ%d\n", kvm_vgic_global_state.maint_irq);
 451         return 0;
 452
 453 out_free_irq:
 454         free_percpu_irq(kvm_vgic_global_state.maint_irq,
 455                         kvm_get_running_vcpus());
 456         return ret;
 457 }