arch/x86/kvm/assigned-dev.c

   1 /*
   2  * Kernel-based Virtual Machine - device assignment support
   3  *
   4  * Copyright (C) 2010 Red Hat, Inc. and/or its affiliates.
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2.  See
   7  * the COPYING file in the top-level directory.
   8  *
   9  */
  10
  11 #include <linux/kvm_host.h>
  12 #include <linux/kvm.h>
  13 #include <linux/uaccess.h>
  14 #include <linux/vmalloc.h>
  15 #include <linux/errno.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/pci.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/slab.h>
  20 #include <linux/namei.h>
  21 #include <linux/fs.h>
  22 #include "irq.h"
  23 #include "assigned-dev.h"
  24 #include "trace/events/kvm.h"
  25
  26 struct kvm_assigned_dev_kernel {
  27         struct kvm_irq_ack_notifier ack_notifier;
  28         struct list_head list;
  29         int assigned_dev_id;
  30         int host_segnr;
  31         int host_busnr;
  32         int host_devfn;
  33         unsigned int entries_nr;
  34         int host_irq;
  35         bool host_irq_disabled;
  36         bool pci_2_3;
  37         struct msix_entry *host_msix_entries;
  38         int guest_irq;
  39         struct msix_entry *guest_msix_entries;
  40         unsigned long irq_requested_type;
  41         int irq_source_id;
  42         int flags;
  43         struct pci_dev *dev;
  44         struct kvm *kvm;
  45         spinlock_t intx_lock;
  46         spinlock_t intx_mask_lock;
  47         char irq_name[32];
  48         struct pci_saved_state *pci_saved_state;
  49 };
  50
  51 static struct kvm_assigned_dev_kernel *kvm_find_assigned_dev(struct list_head *head,
  52                                                       int assigned_dev_id)
  53 {
  54         struct kvm_assigned_dev_kernel *match;
  55
  56         list_for_each_entry(match, head, list) {
  57                 if (match->assigned_dev_id == assigned_dev_id)
  58                         return match;
  59         }
  60         return NULL;
  61 }
  62
  63 static int find_index_from_host_irq(struct kvm_assigned_dev_kernel
  64                                     *assigned_dev, int irq)
  65 {
  66         int i, index;
  67         struct msix_entry *host_msix_entries;
  68
  69         host_msix_entries = assigned_dev->host_msix_entries;
  70
  71         index = -1;
  72         for (i = 0; i < assigned_dev->entries_nr; i++)
  73                 if (irq == host_msix_entries[i].vector) {
  74                         index = i;
  75                         break;
  76                 }
  77         if (index < 0)
  78                 printk(KERN_WARNING "Fail to find correlated MSI-X entry!\n");
  79
  80         return index;
  81 }
  82
  83 static irqreturn_t kvm_assigned_dev_intx(int irq, void *dev_id)
  84 {
  85         struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
  86         int ret;
  87
  88         spin_lock(&assigned_dev->intx_lock);
  89         if (pci_check_and_mask_intx(assigned_dev->dev)) {
  90                 assigned_dev->host_irq_disabled = true;
  91                 ret = IRQ_WAKE_THREAD;
  92         } else
  93                 ret = IRQ_NONE;
  94         spin_unlock(&assigned_dev->intx_lock);
  95
  96         return ret;
  97 }
  98
  99 static void
 100 kvm_assigned_dev_raise_guest_irq(struct kvm_assigned_dev_kernel *assigned_dev,
 101                                  int vector)
 102 {
 103         if (unlikely(assigned_dev->irq_requested_type &
 104                      KVM_DEV_IRQ_GUEST_INTX)) {
 105                 spin_lock(&assigned_dev->intx_mask_lock);
 106                 if (!(assigned_dev->flags & KVM_DEV_ASSIGN_MASK_INTX))
 107                         kvm_set_irq(assigned_dev->kvm,
 108                                     assigned_dev->irq_source_id, vector, 1,
 109                                     false);
 110                 spin_unlock(&assigned_dev->intx_mask_lock);
 111         } else
 112                 kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,
 113                             vector, 1, false);
 114 }
 115
 116 static irqreturn_t kvm_assigned_dev_thread_intx(int irq, void *dev_id)
 117 {
 118         struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
 119
 120         if (!(assigned_dev->flags & KVM_DEV_ASSIGN_PCI_2_3)) {
 121                 spin_lock_irq(&assigned_dev->intx_lock);
 122                 disable_irq_nosync(irq);
 123                 assigned_dev->host_irq_disabled = true;
 124                 spin_unlock_irq(&assigned_dev->intx_lock);
 125         }
 126
 127         kvm_assigned_dev_raise_guest_irq(assigned_dev,
 128                                          assigned_dev->guest_irq);
 129
 130         return IRQ_HANDLED;
 131 }
 132
 133 /*
 134  * Deliver an IRQ in an atomic context if we can, or return a failure,
 135  * user can retry in a process context.
 136  * Return value:
 137  *  -EWOULDBLOCK - Can't deliver in atomic context: retry in a process context.
 138  *  Other values - No need to retry.
 139  */
 140 static int kvm_set_irq_inatomic(struct kvm *kvm, int irq_source_id, u32 irq,
 141                                 int level)
 142 {
 143         struct kvm_kernel_irq_routing_entry entries[KVM_NR_IRQCHIPS];
 144         struct kvm_kernel_irq_routing_entry *e;
 145         int ret = -EINVAL;
 146         int idx;
 147
 148         trace_kvm_set_irq(irq, level, irq_source_id);
 149
 150         /*
 151          * Injection into either PIC or IOAPIC might need to scan all CPUs,
 152          * which would need to be retried from thread context;  when same GSI
 153          * is connected to both PIC and IOAPIC, we'd have to report a
 154          * partial failure here.
 155          * Since there's no easy way to do this, we only support injecting MSI
 156          * which is limited to 1:1 GSI mapping.
 157          */
 158         idx = srcu_read_lock(&kvm->irq_srcu);
 159         if (kvm_irq_map_gsi(kvm, entries, irq) > 0) {
 160                 e = &entries[0];
 161                 ret = kvm_arch_set_irq_inatomic(e, kvm, irq_source_id,
 162                                                 irq, level);
 163         }
 164         srcu_read_unlock(&kvm->irq_srcu, idx);
 165         return ret;
 166 }
 167
 168
 169 static irqreturn_t kvm_assigned_dev_msi(int irq, void *dev_id)
 170 {
 171         struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
 172         int ret = kvm_set_irq_inatomic(assigned_dev->kvm,
 173                                        assigned_dev->irq_source_id,
 174                                        assigned_dev->guest_irq, 1);
 175         return unlikely(ret == -EWOULDBLOCK) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
 176 }
 177
 178 static irqreturn_t kvm_assigned_dev_thread_msi(int irq, void *dev_id)
 179 {
 180         struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
 181
 182         kvm_assigned_dev_raise_guest_irq(assigned_dev,
 183                                          assigned_dev->guest_irq);
 184
 185         return IRQ_HANDLED;
 186 }
 187
 188 static irqreturn_t kvm_assigned_dev_msix(int irq, void *dev_id)
 189 {
 190         struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
 191         int index = find_index_from_host_irq(assigned_dev, irq);
 192         u32 vector;
 193         int ret = 0;
 194
 195         if (index >= 0) {
 196                 vector = assigned_dev->guest_msix_entries[index].vector;
 197                 ret = kvm_set_irq_inatomic(assigned_dev->kvm,
 198                                            assigned_dev->irq_source_id,
 199                                            vector, 1);
 200         }
 201
 202         return unlikely(ret == -EWOULDBLOCK) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
 203 }
 204
 205 static irqreturn_t kvm_assigned_dev_thread_msix(int irq, void *dev_id)
 206 {
 207         struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
 208         int index = find_index_from_host_irq(assigned_dev, irq);
 209         u32 vector;
 210
 211         if (index >= 0) {
 212                 vector = assigned_dev->guest_msix_entries[index].vector;
 213                 kvm_assigned_dev_raise_guest_irq(assigned_dev, vector);
 214         }
 215
 216         return IRQ_HANDLED;
 217 }
 218
 219 /* Ack the irq line for an assigned device */
 220 static void kvm_assigned_dev_ack_irq(struct kvm_irq_ack_notifier *kian)
 221 {
 222         struct kvm_assigned_dev_kernel *dev =
 223                 container_of(kian, struct kvm_assigned_dev_kernel,
 224                              ack_notifier);
 225
 226         kvm_set_irq(dev->kvm, dev->irq_source_id, dev->guest_irq, 0, false);
 227
 228         spin_lock(&dev->intx_mask_lock);
 229
 230         if (!(dev->flags & KVM_DEV_ASSIGN_MASK_INTX)) {
 231                 bool reassert = false;
 232
 233                 spin_lock_irq(&dev->intx_lock);
 234                 /*
 235                  * The guest IRQ may be shared so this ack can come from an
 236                  * IRQ for another guest device.
 237                  */
 238                 if (dev->host_irq_disabled) {
 239                         if (!(dev->flags & KVM_DEV_ASSIGN_PCI_2_3))
 240                                 enable_irq(dev->host_irq);
 241                         else if (!pci_check_and_unmask_intx(dev->dev))
 242                                 reassert = true;
 243                         dev->host_irq_disabled = reassert;
 244                 }
 245                 spin_unlock_irq(&dev->intx_lock);
 246
 247                 if (reassert)
 248                         kvm_set_irq(dev->kvm, dev->irq_source_id,
 249                                     dev->guest_irq, 1, false);
 250         }
 251
 252         spin_unlock(&dev->intx_mask_lock);
 253 }
 254
 255 static void deassign_guest_irq(struct kvm *kvm,
 256                                struct kvm_assigned_dev_kernel *assigned_dev)
 257 {
 258         if (assigned_dev->ack_notifier.gsi != -1)
 259                 kvm_unregister_irq_ack_notifier(kvm,
 260                                                 &assigned_dev->ack_notifier);
 261
 262         kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,
 263                     assigned_dev->guest_irq, 0, false);
 264
 265         if (assigned_dev->irq_source_id != -1)
 266                 kvm_free_irq_source_id(kvm, assigned_dev->irq_source_id);
 267         assigned_dev->irq_source_id = -1;
 268         assigned_dev->irq_requested_type &= ~(KVM_DEV_IRQ_GUEST_MASK);
 269 }
 270
 271 /* The function implicit hold kvm->lock mutex due to cancel_work_sync() */
 272 static void deassign_host_irq(struct kvm *kvm,
 273                               struct kvm_assigned_dev_kernel *assigned_dev)
 274 {
 275         /*
 276          * We disable irq here to prevent further events.
 277          *
 278          * Notice this maybe result in nested disable if the interrupt type is
 279          * INTx, but it's OK for we are going to free it.
 280          *
 281          * If this function is a part of VM destroy, please ensure that till
 282          * now, the kvm state is still legal for probably we also have to wait
 283          * on a currently running IRQ handler.
 284          */
 285         if (assigned_dev->irq_requested_type & KVM_DEV_IRQ_HOST_MSIX) {
 286                 int i;
 287                 for (i = 0; i < assigned_dev->entries_nr; i++)
 288                         disable_irq(assigned_dev->host_msix_entries[i].vector);
 289
 290                 for (i = 0; i < assigned_dev->entries_nr; i++)
 291                         free_irq(assigned_dev->host_msix_entries[i].vector,
 292                                  assigned_dev);
 293
 294                 assigned_dev->entries_nr = 0;
 295                 kfree(assigned_dev->host_msix_entries);
 296                 kfree(assigned_dev->guest_msix_entries);
 297                 pci_disable_msix(assigned_dev->dev);
 298         } else {
 299                 /* Deal with MSI and INTx */
 300                 if ((assigned_dev->irq_requested_type &
 301                      KVM_DEV_IRQ_HOST_INTX) &&
 302                     (assigned_dev->flags & KVM_DEV_ASSIGN_PCI_2_3)) {
 303                         spin_lock_irq(&assigned_dev->intx_lock);
 304                         pci_intx(assigned_dev->dev, false);
 305                         spin_unlock_irq(&assigned_dev->intx_lock);
 306                         synchronize_irq(assigned_dev->host_irq);
 307                 } else
 308                         disable_irq(assigned_dev->host_irq);
 309
 310                 free_irq(assigned_dev->host_irq, assigned_dev);
 311
 312                 if (assigned_dev->irq_requested_type & KVM_DEV_IRQ_HOST_MSI)
 313                         pci_disable_msi(assigned_dev->dev);
 314         }
 315
 316         assigned_dev->irq_requested_type &= ~(KVM_DEV_IRQ_HOST_MASK);
 317 }
 318
 319 static int kvm_deassign_irq(struct kvm *kvm,
 320                             struct kvm_assigned_dev_kernel *assigned_dev,
 321                             unsigned long irq_requested_type)
 322 {
 323         unsigned long guest_irq_type, host_irq_type;
 324
 325         if (!irqchip_in_kernel(kvm))
 326                 return -EINVAL;
 327         /* no irq assignment to deassign */
 328         if (!assigned_dev->irq_requested_type)
 329                 return -ENXIO;
 330
 331         host_irq_type = irq_requested_type & KVM_DEV_IRQ_HOST_MASK;
 332         guest_irq_type = irq_requested_type & KVM_DEV_IRQ_GUEST_MASK;
 333
 334         if (host_irq_type)
 335                 deassign_host_irq(kvm, assigned_dev);
 336         if (guest_irq_type)
 337                 deassign_guest_irq(kvm, assigned_dev);
 338
 339         return 0;
 340 }
 341
 342 static void kvm_free_assigned_irq(struct kvm *kvm,
 343                                   struct kvm_assigned_dev_kernel *assigned_dev)
 344 {
 345         kvm_deassign_irq(kvm, assigned_dev, assigned_dev->irq_requested_type);
 346 }
 347
 348 static void kvm_free_assigned_device(struct kvm *kvm,
 349                                      struct kvm_assigned_dev_kernel
 350                                      *assigned_dev)
 351 {
 352         kvm_free_assigned_irq(kvm, assigned_dev);
 353
 354         pci_reset_function(assigned_dev->dev);
 355         if (pci_load_and_free_saved_state(assigned_dev->dev,
 356                                           &assigned_dev->pci_saved_state))
 357                 printk(KERN_INFO "%s: Couldn't reload %s saved state\n",
 358                        __func__, dev_name(&assigned_dev->dev->dev));
 359         else
 360                 pci_restore_state(assigned_dev->dev);
 361
 362         pci_clear_dev_assigned(assigned_dev->dev);
 363
 364         pci_release_regions(assigned_dev->dev);
 365         pci_disable_device(assigned_dev->dev);
 366         pci_dev_put(assigned_dev->dev);
 367
 368         list_del(&assigned_dev->list);
 369         kfree(assigned_dev);
 370 }
 371
 372 void kvm_free_all_assigned_devices(struct kvm *kvm)
 373 {
 374         struct kvm_assigned_dev_kernel *assigned_dev, *tmp;
 375
 376         list_for_each_entry_safe(assigned_dev, tmp,
 377                                  &kvm->arch.assigned_dev_head, list) {
 378                 kvm_free_assigned_device(kvm, assigned_dev);
 379         }
 380 }
 381
 382 static int assigned_device_enable_host_intx(struct kvm *kvm,
 383                                             struct kvm_assigned_dev_kernel *dev)
 384 {
 385         irq_handler_t irq_handler;
 386         unsigned long flags;
 387
 388         dev->host_irq = dev->dev->irq;
 389
 390         /*
 391          * We can only share the IRQ line with other host devices if we are
 392          * able to disable the IRQ source at device-level - independently of
 393          * the guest driver. Otherwise host devices may suffer from unbounded
 394          * IRQ latencies when the guest keeps the line asserted.
 395          */
 396         if (dev->flags & KVM_DEV_ASSIGN_PCI_2_3) {
 397                 irq_handler = kvm_assigned_dev_intx;
 398                 flags = IRQF_SHARED;
 399         } else {
 400                 irq_handler = NULL;
 401                 flags = IRQF_ONESHOT;
 402         }
 403         if (request_threaded_irq(dev->host_irq, irq_handler,
 404                                  kvm_assigned_dev_thread_intx, flags,
 405                                  dev->irq_name, dev))
 406                 return -EIO;
 407
 408         if (dev->flags & KVM_DEV_ASSIGN_PCI_2_3) {
 409                 spin_lock_irq(&dev->intx_lock);
 410                 pci_intx(dev->dev, true);
 411                 spin_unlock_irq(&dev->intx_lock);
 412         }
 413         return 0;
 414 }
 415
 416 static int assigned_device_enable_host_msi(struct kvm *kvm,
 417                                            struct kvm_assigned_dev_kernel *dev)
 418 {
 419         int r;
 420
 421         if (!dev->dev->msi_enabled) {
 422                 r = pci_enable_msi(dev->dev);
 423                 if (r)
 424                         return r;
 425         }
 426
 427         dev->host_irq = dev->dev->irq;
 428         if (request_threaded_irq(dev->host_irq, kvm_assigned_dev_msi,
 429                                  kvm_assigned_dev_thread_msi, 0,
 430                                  dev->irq_name, dev)) {
 431                 pci_disable_msi(dev->dev);
 432                 return -EIO;
 433         }
 434
 435         return 0;
 436 }
 437
 438 static int assigned_device_enable_host_msix(struct kvm *kvm,
 439                                             struct kvm_assigned_dev_kernel *dev)
 440 {
 441         int i, r = -EINVAL;
 442
 443         /* host_msix_entries and guest_msix_entries should have been
 444          * initialized */
 445         if (dev->entries_nr == 0)
 446                 return r;
 447
 448         r = pci_enable_msix_exact(dev->dev,
 449                                   dev->host_msix_entries, dev->entries_nr);
 450         if (r)
 451                 return r;
 452
 453         for (i = 0; i < dev->entries_nr; i++) {
 454                 r = request_threaded_irq(dev->host_msix_entries[i].vector,
 455                                          kvm_assigned_dev_msix,
 456                                          kvm_assigned_dev_thread_msix,
 457                                          0, dev->irq_name, dev);
 458                 if (r)
 459                         goto err;
 460         }
 461
 462         return 0;
 463 err:
 464         for (i -= 1; i >= 0; i--)
 465                 free_irq(dev->host_msix_entries[i].vector, dev);
 466         pci_disable_msix(dev->dev);
 467         return r;
 468 }
 469
 470 static int assigned_device_enable_guest_intx(struct kvm *kvm,
 471                                 struct kvm_assigned_dev_kernel *dev,
 472                                 struct kvm_assigned_irq *irq)
 473 {
 474         dev->guest_irq = irq->guest_irq;
 475         dev->ack_notifier.gsi = irq->guest_irq;
 476         return 0;
 477 }
 478
 479 static int assigned_device_enable_guest_msi(struct kvm *kvm,
 480                         struct kvm_assigned_dev_kernel *dev,
 481                         struct kvm_assigned_irq *irq)
 482 {
 483         dev->guest_irq = irq->guest_irq;
 484         dev->ack_notifier.gsi = -1;
 485         return 0;
 486 }
 487
 488 static int assigned_device_enable_guest_msix(struct kvm *kvm,
 489                         struct kvm_assigned_dev_kernel *dev,
 490                         struct kvm_assigned_irq *irq)
 491 {
 492         dev->guest_irq = irq->guest_irq;
 493         dev->ack_notifier.gsi = -1;
 494         return 0;
 495 }
 496
 497 static int assign_host_irq(struct kvm *kvm,
 498                            struct kvm_assigned_dev_kernel *dev,
 499                            __u32 host_irq_type)
 500 {
 501         int r = -EEXIST;
 502
 503         if (dev->irq_requested_type & KVM_DEV_IRQ_HOST_MASK)
 504                 return r;
 505
 506         snprintf(dev->irq_name, sizeof(dev->irq_name), "kvm:%s",
 507                  pci_name(dev->dev));
 508
 509         switch (host_irq_type) {
 510         case KVM_DEV_IRQ_HOST_INTX:
 511                 r = assigned_device_enable_host_intx(kvm, dev);
 512                 break;
 513         case KVM_DEV_IRQ_HOST_MSI:
 514                 r = assigned_device_enable_host_msi(kvm, dev);
 515                 break;
 516         case KVM_DEV_IRQ_HOST_MSIX:
 517                 r = assigned_device_enable_host_msix(kvm, dev);
 518                 break;
 519         default:
 520                 r = -EINVAL;
 521         }
 522         dev->host_irq_disabled = false;
 523
 524         if (!r)
 525                 dev->irq_requested_type |= host_irq_type;
 526
 527         return r;
 528 }
 529
 530 static int assign_guest_irq(struct kvm *kvm,
 531                             struct kvm_assigned_dev_kernel *dev,
 532                             struct kvm_assigned_irq *irq,
 533                             unsigned long guest_irq_type)
 534 {
 535         int id;
 536         int r = -EEXIST;
 537
 538         if (dev->irq_requested_type & KVM_DEV_IRQ_GUEST_MASK)
 539                 return r;
 540
 541         id = kvm_request_irq_source_id(kvm);
 542         if (id < 0)
 543                 return id;
 544
 545         dev->irq_source_id = id;
 546
 547         switch (guest_irq_type) {
 548         case KVM_DEV_IRQ_GUEST_INTX:
 549                 r = assigned_device_enable_guest_intx(kvm, dev, irq);
 550                 break;
 551         case KVM_DEV_IRQ_GUEST_MSI:
 552                 r = assigned_device_enable_guest_msi(kvm, dev, irq);
 553                 break;
 554         case KVM_DEV_IRQ_GUEST_MSIX:
 555                 r = assigned_device_enable_guest_msix(kvm, dev, irq);
 556                 break;
 557         default:
 558                 r = -EINVAL;
 559         }
 560
 561         if (!r) {
 562                 dev->irq_requested_type |= guest_irq_type;
 563                 if (dev->ack_notifier.gsi != -1)
 564                         kvm_register_irq_ack_notifier(kvm, &dev->ack_notifier);
 565         } else {
 566                 kvm_free_irq_source_id(kvm, dev->irq_source_id);
 567                 dev->irq_source_id = -1;
 568         }
 569
 570         return r;
 571 }
 572
 573 /* TODO Deal with KVM_DEV_IRQ_ASSIGNED_MASK_MSIX */
 574 static int kvm_vm_ioctl_assign_irq(struct kvm *kvm,
 575                                    struct kvm_assigned_irq *assigned_irq)
 576 {
 577         int r = -EINVAL;
 578         struct kvm_assigned_dev_kernel *match;
 579         unsigned long host_irq_type, guest_irq_type;
 580
 581         if (!irqchip_in_kernel(kvm))
 582                 return r;
 583
 584         mutex_lock(&kvm->lock);
 585         r = -ENODEV;
 586         match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
 587                                       assigned_irq->assigned_dev_id);
 588         if (!match)
 589                 goto out;
 590
 591         host_irq_type = (assigned_irq->flags & KVM_DEV_IRQ_HOST_MASK);
 592         guest_irq_type = (assigned_irq->flags & KVM_DEV_IRQ_GUEST_MASK);
 593
 594         r = -EINVAL;
 595         /* can only assign one type at a time */
 596         if (hweight_long(host_irq_type) > 1)
 597                 goto out;
 598         if (hweight_long(guest_irq_type) > 1)
 599                 goto out;
 600         if (host_irq_type == 0 && guest_irq_type == 0)
 601                 goto out;
 602
 603         r = 0;
 604         if (host_irq_type)
 605                 r = assign_host_irq(kvm, match, host_irq_type);
 606         if (r)
 607                 goto out;
 608
 609         if (guest_irq_type)
 610                 r = assign_guest_irq(kvm, match, assigned_irq, guest_irq_type);
 611 out:
 612         mutex_unlock(&kvm->lock);
 613         return r;
 614 }
 615
 616 static int kvm_vm_ioctl_deassign_dev_irq(struct kvm *kvm,
 617                                          struct kvm_assigned_irq
 618                                          *assigned_irq)
 619 {
 620         int r = -ENODEV;
 621         struct kvm_assigned_dev_kernel *match;
 622         unsigned long irq_type;
 623
 624         mutex_lock(&kvm->lock);
 625
 626         match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
 627                                       assigned_irq->assigned_dev_id);
 628         if (!match)
 629                 goto out;
 630
 631         irq_type = assigned_irq->flags & (KVM_DEV_IRQ_HOST_MASK |
 632                                           KVM_DEV_IRQ_GUEST_MASK);
 633         r = kvm_deassign_irq(kvm, match, irq_type);
 634 out:
 635         mutex_unlock(&kvm->lock);
 636         return r;
 637 }
 638
 639 /*
 640  * We want to test whether the caller has been granted permissions to
 641  * use this device.  To be able to configure and control the device,
 642  * the user needs access to PCI configuration space and BAR resources.
 643  * These are accessed through PCI sysfs.  PCI config space is often
 644  * passed to the process calling this ioctl via file descriptor, so we
 645  * can't rely on access to that file.  We can check for permissions
 646  * on each of the BAR resource files, which is a pretty clear
 647  * indicator that the user has been granted access to the device.
 648  */
 649 static int probe_sysfs_permissions(struct pci_dev *dev)
 650 {
 651 #ifdef CONFIG_SYSFS
 652         int i;
 653         bool bar_found = false;
 654
 655         for (i = PCI_STD_RESOURCES; i <= PCI_STD_RESOURCE_END; i++) {
 656                 char *kpath, *syspath;
 657                 struct path path;
 658                 struct inode *inode;
 659                 int r;
 660
 661                 if (!pci_resource_len(dev, i))
 662                         continue;
 663
 664                 kpath = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
 665                 if (!kpath)
 666                         return -ENOMEM;
 667
 668                 /* Per sysfs-rules, sysfs is always at /sys */
 669                 syspath = kasprintf(GFP_KERNEL, "/sys%s/resource%d", kpath, i);
 670                 kfree(kpath);
 671                 if (!syspath)
 672                         return -ENOMEM;
 673
 674                 r = kern_path(syspath, LOOKUP_FOLLOW, &path);
 675                 kfree(syspath);
 676                 if (r)
 677                         return r;
 678
 679                 inode = d_backing_inode(path.dentry);
 680
 681                 r = inode_permission(inode, MAY_READ | MAY_WRITE | MAY_ACCESS);
 682                 path_put(&path);
 683                 if (r)
 684                         return r;
 685
 686                 bar_found = true;
 687         }
 688
 689         /* If no resources, probably something special */
 690         if (!bar_found)
 691                 return -EPERM;
 692
 693         return 0;
 694 #else
 695         return -EINVAL; /* No way to control the device without sysfs */
 696 #endif
 697 }
 698
 699 static int kvm_vm_ioctl_assign_device(struct kvm *kvm,
 700                                       struct kvm_assigned_pci_dev *assigned_dev)
 701 {
 702         int r = 0, idx;
 703         struct kvm_assigned_dev_kernel *match;
 704         struct pci_dev *dev;
 705
 706         if (!(assigned_dev->flags & KVM_DEV_ASSIGN_ENABLE_IOMMU))
 707                 return -EINVAL;
 708
 709         mutex_lock(&kvm->lock);
 710         idx = srcu_read_lock(&kvm->srcu);
 711
 712         match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
 713                                       assigned_dev->assigned_dev_id);
 714         if (match) {
 715                 /* device already assigned */
 716                 r = -EEXIST;
 717                 goto out;
 718         }
 719
 720         match = kzalloc(sizeof(struct kvm_assigned_dev_kernel), GFP_KERNEL);
 721         if (match == NULL) {
 722                 printk(KERN_INFO "%s: Couldn't allocate memory\n",
 723                        __func__);
 724                 r = -ENOMEM;
 725                 goto out;
 726         }
 727         dev = pci_get_domain_bus_and_slot(assigned_dev->segnr,
 728                                    assigned_dev->busnr,
 729                                    assigned_dev->devfn);
 730         if (!dev) {
 731                 printk(KERN_INFO "%s: host device not found\n", __func__);
 732                 r = -EINVAL;
 733                 goto out_free;
 734         }
 735
 736         /* Don't allow bridges to be assigned */
 737         if (dev->hdr_type != PCI_HEADER_TYPE_NORMAL) {
 738                 r = -EPERM;
 739                 goto out_put;
 740         }
 741
 742         r = probe_sysfs_permissions(dev);
 743         if (r)
 744                 goto out_put;
 745
 746         if (pci_enable_device(dev)) {
 747                 printk(KERN_INFO "%s: Could not enable PCI device\n", __func__);
 748                 r = -EBUSY;
 749                 goto out_put;
 750         }
 751         r = pci_request_regions(dev, "kvm_assigned_device");
 752         if (r) {
 753                 printk(KERN_INFO "%s: Could not get access to device regions\n",
 754                        __func__);
 755                 goto out_disable;
 756         }
 757
 758         pci_reset_function(dev);
 759         pci_save_state(dev);
 760         match->pci_saved_state = pci_store_saved_state(dev);
 761         if (!match->pci_saved_state)
 762                 printk(KERN_DEBUG "%s: Couldn't store %s saved state\n",
 763                        __func__, dev_name(&dev->dev));
 764
 765         if (!pci_intx_mask_supported(dev))
 766                 assigned_dev->flags &= ~KVM_DEV_ASSIGN_PCI_2_3;
 767
 768         match->assigned_dev_id = assigned_dev->assigned_dev_id;
 769         match->host_segnr = assigned_dev->segnr;
 770         match->host_busnr = assigned_dev->busnr;
 771         match->host_devfn = assigned_dev->devfn;
 772         match->flags = assigned_dev->flags;
 773         match->dev = dev;
 774         spin_lock_init(&match->intx_lock);
 775         spin_lock_init(&match->intx_mask_lock);
 776         match->irq_source_id = -1;
 777         match->kvm = kvm;
 778         match->ack_notifier.irq_acked = kvm_assigned_dev_ack_irq;
 779
 780         list_add(&match->list, &kvm->arch.assigned_dev_head);
 781
 782         if (!kvm->arch.iommu_domain) {
 783                 r = kvm_iommu_map_guest(kvm);
 784                 if (r)
 785                         goto out_list_del;
 786         }
 787         r = kvm_assign_device(kvm, match->dev);
 788         if (r)
 789                 goto out_list_del;
 790
 791 out:
 792         srcu_read_unlock(&kvm->srcu, idx);
 793         mutex_unlock(&kvm->lock);
 794         return r;
 795 out_list_del:
 796         if (pci_load_and_free_saved_state(dev, &match->pci_saved_state))
 797                 printk(KERN_INFO "%s: Couldn't reload %s saved state\n",
 798                        __func__, dev_name(&dev->dev));
 799         list_del(&match->list);
 800         pci_release_regions(dev);
 801 out_disable:
 802         pci_disable_device(dev);
 803 out_put:
 804         pci_dev_put(dev);
 805 out_free:
 806         kfree(match);
 807         srcu_read_unlock(&kvm->srcu, idx);
 808         mutex_unlock(&kvm->lock);
 809         return r;
 810 }
 811
 812 static int kvm_vm_ioctl_deassign_device(struct kvm *kvm,
 813                 struct kvm_assigned_pci_dev *assigned_dev)
 814 {
 815         int r = 0;
 816         struct kvm_assigned_dev_kernel *match;
 817
 818         mutex_lock(&kvm->lock);
 819
 820         match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
 821                                       assigned_dev->assigned_dev_id);
 822         if (!match) {
 823                 printk(KERN_INFO "%s: device hasn't been assigned before, "
 824                   "so cannot be deassigned\n", __func__);
 825                 r = -EINVAL;
 826                 goto out;
 827         }
 828
 829         kvm_deassign_device(kvm, match->dev);
 830
 831         kvm_free_assigned_device(kvm, match);
 832
 833 out:
 834         mutex_unlock(&kvm->lock);
 835         return r;
 836 }
 837
 838
 839 static int kvm_vm_ioctl_set_msix_nr(struct kvm *kvm,
 840                                     struct kvm_assigned_msix_nr *entry_nr)
 841 {
 842         int r = 0;
 843         struct kvm_assigned_dev_kernel *adev;
 844
 845         mutex_lock(&kvm->lock);
 846
 847         adev = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
 848                                       entry_nr->assigned_dev_id);
 849         if (!adev) {
 850                 r = -EINVAL;
 851                 goto msix_nr_out;
 852         }
 853
 854         if (adev->entries_nr == 0) {
 855                 adev->entries_nr = entry_nr->entry_nr;
 856                 if (adev->entries_nr == 0 ||
 857                     adev->entries_nr > KVM_MAX_MSIX_PER_DEV) {
 858                         r = -EINVAL;
 859                         goto msix_nr_out;
 860                 }
 861
 862                 adev->host_msix_entries = kzalloc(sizeof(struct msix_entry) *
 863                                                 entry_nr->entry_nr,
 864                                                 GFP_KERNEL);
 865                 if (!adev->host_msix_entries) {
 866                         r = -ENOMEM;
 867                         goto msix_nr_out;
 868                 }
 869                 adev->guest_msix_entries =
 870                         kzalloc(sizeof(struct msix_entry) * entry_nr->entry_nr,
 871                                 GFP_KERNEL);
 872                 if (!adev->guest_msix_entries) {
 873                         kfree(adev->host_msix_entries);
 874                         r = -ENOMEM;
 875                         goto msix_nr_out;
 876                 }
 877         } else /* Not allowed set MSI-X number twice */
 878                 r = -EINVAL;
 879 msix_nr_out:
 880         mutex_unlock(&kvm->lock);
 881         return r;
 882 }
 883
 884 static int kvm_vm_ioctl_set_msix_entry(struct kvm *kvm,
 885                                        struct kvm_assigned_msix_entry *entry)
 886 {
 887         int r = 0, i;
 888         struct kvm_assigned_dev_kernel *adev;
 889
 890         mutex_lock(&kvm->lock);
 891
 892         adev = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
 893                                       entry->assigned_dev_id);
 894
 895         if (!adev) {
 896                 r = -EINVAL;
 897                 goto msix_entry_out;
 898         }
 899
 900         for (i = 0; i < adev->entries_nr; i++)
 901                 if (adev->guest_msix_entries[i].vector == 0 ||
 902                     adev->guest_msix_entries[i].entry == entry->entry) {
 903                         adev->guest_msix_entries[i].entry = entry->entry;
 904                         adev->guest_msix_entries[i].vector = entry->gsi;
 905                         adev->host_msix_entries[i].entry = entry->entry;
 906                         break;
 907                 }
 908         if (i == adev->entries_nr) {
 909                 r = -ENOSPC;
 910                 goto msix_entry_out;
 911         }
 912
 913 msix_entry_out:
 914         mutex_unlock(&kvm->lock);
 915
 916         return r;
 917 }
 918
 919 static int kvm_vm_ioctl_set_pci_irq_mask(struct kvm *kvm,
 920                 struct kvm_assigned_pci_dev *assigned_dev)
 921 {
 922         int r = 0;
 923         struct kvm_assigned_dev_kernel *match;
 924
 925         mutex_lock(&kvm->lock);
 926
 927         match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
 928                                       assigned_dev->assigned_dev_id);
 929         if (!match) {
 930                 r = -ENODEV;
 931                 goto out;
 932         }
 933
 934         spin_lock(&match->intx_mask_lock);
 935
 936         match->flags &= ~KVM_DEV_ASSIGN_MASK_INTX;
 937         match->flags |= assigned_dev->flags & KVM_DEV_ASSIGN_MASK_INTX;
 938
 939         if (match->irq_requested_type & KVM_DEV_IRQ_GUEST_INTX) {
 940                 if (assigned_dev->flags & KVM_DEV_ASSIGN_MASK_INTX) {
 941                         kvm_set_irq(match->kvm, match->irq_source_id,
 942                                     match->guest_irq, 0, false);
 943                         /*
 944                          * Masking at hardware-level is performed on demand,
 945                          * i.e. when an IRQ actually arrives at the host.
 946                          */
 947                 } else if (!(assigned_dev->flags & KVM_DEV_ASSIGN_PCI_2_3)) {
 948                         /*
 949                          * Unmask the IRQ line if required. Unmasking at
 950                          * device level will be performed by user space.
 951                          */
 952                         spin_lock_irq(&match->intx_lock);
 953                         if (match->host_irq_disabled) {
 954                                 enable_irq(match->host_irq);
 955                                 match->host_irq_disabled = false;
 956                         }
 957                         spin_unlock_irq(&match->intx_lock);
 958                 }
 959         }
 960
 961         spin_unlock(&match->intx_mask_lock);
 962
 963 out:
 964         mutex_unlock(&kvm->lock);
 965         return r;
 966 }
 967
 968 long kvm_vm_ioctl_assigned_device(struct kvm *kvm, unsigned ioctl,
 969                                   unsigned long arg)
 970 {
 971         void __user *argp = (void __user *)arg;
 972         int r;
 973
 974         switch (ioctl) {
 975         case KVM_ASSIGN_PCI_DEVICE: {
 976                 struct kvm_assigned_pci_dev assigned_dev;
 977
 978                 r = -EFAULT;
 979                 if (copy_from_user(&assigned_dev, argp, sizeof assigned_dev))
 980                         goto out;
 981                 r = kvm_vm_ioctl_assign_device(kvm, &assigned_dev);
 982                 if (r)
 983                         goto out;
 984                 break;
 985         }
 986         case KVM_ASSIGN_IRQ: {
 987                 r = -EOPNOTSUPP;
 988                 break;
 989         }
 990         case KVM_ASSIGN_DEV_IRQ: {
 991                 struct kvm_assigned_irq assigned_irq;
 992
 993                 r = -EFAULT;
 994                 if (copy_from_user(&assigned_irq, argp, sizeof assigned_irq))
 995                         goto out;
 996                 r = kvm_vm_ioctl_assign_irq(kvm, &assigned_irq);
 997                 if (r)
 998                         goto out;
 999                 break;
1000         }
1001         case KVM_DEASSIGN_DEV_IRQ: {
1002                 struct kvm_assigned_irq assigned_irq;
1003
1004                 r = -EFAULT;
1005                 if (copy_from_user(&assigned_irq, argp, sizeof assigned_irq))
1006                         goto out;
1007                 r = kvm_vm_ioctl_deassign_dev_irq(kvm, &assigned_irq);
1008                 if (r)
1009                         goto out;
1010                 break;
1011         }
1012         case KVM_DEASSIGN_PCI_DEVICE: {
1013                 struct kvm_assigned_pci_dev assigned_dev;
1014
1015                 r = -EFAULT;
1016                 if (copy_from_user(&assigned_dev, argp, sizeof assigned_dev))
1017                         goto out;
1018                 r = kvm_vm_ioctl_deassign_device(kvm, &assigned_dev);
1019                 if (r)
1020                         goto out;
1021                 break;
1022         }
1023         case KVM_ASSIGN_SET_MSIX_NR: {
1024                 struct kvm_assigned_msix_nr entry_nr;
1025                 r = -EFAULT;
1026                 if (copy_from_user(&entry_nr, argp, sizeof entry_nr))
1027                         goto out;
1028                 r = kvm_vm_ioctl_set_msix_nr(kvm, &entry_nr);
1029                 if (r)
1030                         goto out;
1031                 break;
1032         }
1033         case KVM_ASSIGN_SET_MSIX_ENTRY: {
1034                 struct kvm_assigned_msix_entry entry;
1035                 r = -EFAULT;
1036                 if (copy_from_user(&entry, argp, sizeof entry))
1037                         goto out;
1038                 r = kvm_vm_ioctl_set_msix_entry(kvm, &entry);
1039                 if (r)
1040                         goto out;
1041                 break;
1042         }
1043         case KVM_ASSIGN_SET_INTX_MASK: {
1044                 struct kvm_assigned_pci_dev assigned_dev;
1045
1046                 r = -EFAULT;
1047                 if (copy_from_user(&assigned_dev, argp, sizeof assigned_dev))
1048                         goto out;
1049                 r = kvm_vm_ioctl_set_pci_irq_mask(kvm, &assigned_dev);
1050                 break;
1051         }
1052         default:
1053                 r = -ENOTTY;
1054                 break;
1055         }
1056 out:
1057         return r;
1058 }