linux/arch/x86/kvm/assigned-dev.c
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   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
  25struct kvm_assigned_dev_kernel {
  26        struct kvm_irq_ack_notifier ack_notifier;
  27        struct list_head list;
  28        int assigned_dev_id;
  29        int host_segnr;
  30        int host_busnr;
  31        int host_devfn;
  32        unsigned int entries_nr;
  33        int host_irq;
  34        bool host_irq_disabled;
  35        bool pci_2_3;
  36        struct msix_entry *host_msix_entries;
  37        int guest_irq;
  38        struct msix_entry *guest_msix_entries;
  39        unsigned long irq_requested_type;
  40        int irq_source_id;
  41        int flags;
  42        struct pci_dev *dev;
  43        struct kvm *kvm;
  44        spinlock_t intx_lock;
  45        spinlock_t intx_mask_lock;
  46        char irq_name[32];
  47        struct pci_saved_state *pci_saved_state;
  48};
  49
  50static struct kvm_assigned_dev_kernel *kvm_find_assigned_dev(struct list_head *head,
  51                                                      int assigned_dev_id)
  52{
  53        struct list_head *ptr;
  54        struct kvm_assigned_dev_kernel *match;
  55
  56        list_for_each(ptr, head) {
  57                match = list_entry(ptr, struct kvm_assigned_dev_kernel, list);
  58                if (match->assigned_dev_id == assigned_dev_id)
  59                        return match;
  60        }
  61        return NULL;
  62}
  63
  64static int find_index_from_host_irq(struct kvm_assigned_dev_kernel
  65                                    *assigned_dev, int irq)
  66{
  67        int i, index;
  68        struct msix_entry *host_msix_entries;
  69
  70        host_msix_entries = assigned_dev->host_msix_entries;
  71
  72        index = -1;
  73        for (i = 0; i < assigned_dev->entries_nr; i++)
  74                if (irq == host_msix_entries[i].vector) {
  75                        index = i;
  76                        break;
  77                }
  78        if (index < 0)
  79                printk(KERN_WARNING "Fail to find correlated MSI-X entry!\n");
  80
  81        return index;
  82}
  83
  84static irqreturn_t kvm_assigned_dev_intx(int irq, void *dev_id)
  85{
  86        struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
  87        int ret;
  88
  89        spin_lock(&assigned_dev->intx_lock);
  90        if (pci_check_and_mask_intx(assigned_dev->dev)) {
  91                assigned_dev->host_irq_disabled = true;
  92                ret = IRQ_WAKE_THREAD;
  93        } else
  94                ret = IRQ_NONE;
  95        spin_unlock(&assigned_dev->intx_lock);
  96
  97        return ret;
  98}
  99
 100static void
 101kvm_assigned_dev_raise_guest_irq(struct kvm_assigned_dev_kernel *assigned_dev,
 102                                 int vector)
 103{
 104        if (unlikely(assigned_dev->irq_requested_type &
 105                     KVM_DEV_IRQ_GUEST_INTX)) {
 106                spin_lock(&assigned_dev->intx_mask_lock);
 107                if (!(assigned_dev->flags & KVM_DEV_ASSIGN_MASK_INTX))
 108                        kvm_set_irq(assigned_dev->kvm,
 109                                    assigned_dev->irq_source_id, vector, 1,
 110                                    false);
 111                spin_unlock(&assigned_dev->intx_mask_lock);
 112        } else
 113                kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,
 114                            vector, 1, false);
 115}
 116
 117static irqreturn_t kvm_assigned_dev_thread_intx(int irq, void *dev_id)
 118{
 119        struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
 120
 121        if (!(assigned_dev->flags & KVM_DEV_ASSIGN_PCI_2_3)) {
 122                spin_lock_irq(&assigned_dev->intx_lock);
 123                disable_irq_nosync(irq);
 124                assigned_dev->host_irq_disabled = true;
 125                spin_unlock_irq(&assigned_dev->intx_lock);
 126        }
 127
 128        kvm_assigned_dev_raise_guest_irq(assigned_dev,
 129                                         assigned_dev->guest_irq);
 130
 131        return IRQ_HANDLED;
 132}
 133
 134#ifdef __KVM_HAVE_MSI
 135static irqreturn_t kvm_assigned_dev_msi(int irq, void *dev_id)
 136{
 137        struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
 138        int ret = kvm_set_irq_inatomic(assigned_dev->kvm,
 139                                       assigned_dev->irq_source_id,
 140                                       assigned_dev->guest_irq, 1);
 141        return unlikely(ret == -EWOULDBLOCK) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
 142}
 143
 144static irqreturn_t kvm_assigned_dev_thread_msi(int irq, void *dev_id)
 145{
 146        struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
 147
 148        kvm_assigned_dev_raise_guest_irq(assigned_dev,
 149                                         assigned_dev->guest_irq);
 150
 151        return IRQ_HANDLED;
 152}
 153#endif
 154
 155#ifdef __KVM_HAVE_MSIX
 156static irqreturn_t kvm_assigned_dev_msix(int irq, void *dev_id)
 157{
 158        struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
 159        int index = find_index_from_host_irq(assigned_dev, irq);
 160        u32 vector;
 161        int ret = 0;
 162
 163        if (index >= 0) {
 164                vector = assigned_dev->guest_msix_entries[index].vector;
 165                ret = kvm_set_irq_inatomic(assigned_dev->kvm,
 166                                           assigned_dev->irq_source_id,
 167                                           vector, 1);
 168        }
 169
 170        return unlikely(ret == -EWOULDBLOCK) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
 171}
 172
 173static irqreturn_t kvm_assigned_dev_thread_msix(int irq, void *dev_id)
 174{
 175        struct kvm_assigned_dev_kernel *assigned_dev = dev_id;
 176        int index = find_index_from_host_irq(assigned_dev, irq);
 177        u32 vector;
 178
 179        if (index >= 0) {
 180                vector = assigned_dev->guest_msix_entries[index].vector;
 181                kvm_assigned_dev_raise_guest_irq(assigned_dev, vector);
 182        }
 183
 184        return IRQ_HANDLED;
 185}
 186#endif
 187
 188/* Ack the irq line for an assigned device */
 189static void kvm_assigned_dev_ack_irq(struct kvm_irq_ack_notifier *kian)
 190{
 191        struct kvm_assigned_dev_kernel *dev =
 192                container_of(kian, struct kvm_assigned_dev_kernel,
 193                             ack_notifier);
 194
 195        kvm_set_irq(dev->kvm, dev->irq_source_id, dev->guest_irq, 0, false);
 196
 197        spin_lock(&dev->intx_mask_lock);
 198
 199        if (!(dev->flags & KVM_DEV_ASSIGN_MASK_INTX)) {
 200                bool reassert = false;
 201
 202                spin_lock_irq(&dev->intx_lock);
 203                /*
 204                 * The guest IRQ may be shared so this ack can come from an
 205                 * IRQ for another guest device.
 206                 */
 207                if (dev->host_irq_disabled) {
 208                        if (!(dev->flags & KVM_DEV_ASSIGN_PCI_2_3))
 209                                enable_irq(dev->host_irq);
 210                        else if (!pci_check_and_unmask_intx(dev->dev))
 211                                reassert = true;
 212                        dev->host_irq_disabled = reassert;
 213                }
 214                spin_unlock_irq(&dev->intx_lock);
 215
 216                if (reassert)
 217                        kvm_set_irq(dev->kvm, dev->irq_source_id,
 218                                    dev->guest_irq, 1, false);
 219        }
 220
 221        spin_unlock(&dev->intx_mask_lock);
 222}
 223
 224static void deassign_guest_irq(struct kvm *kvm,
 225                               struct kvm_assigned_dev_kernel *assigned_dev)
 226{
 227        if (assigned_dev->ack_notifier.gsi != -1)
 228                kvm_unregister_irq_ack_notifier(kvm,
 229                                                &assigned_dev->ack_notifier);
 230
 231        kvm_set_irq(assigned_dev->kvm, assigned_dev->irq_source_id,
 232                    assigned_dev->guest_irq, 0, false);
 233
 234        if (assigned_dev->irq_source_id != -1)
 235                kvm_free_irq_source_id(kvm, assigned_dev->irq_source_id);
 236        assigned_dev->irq_source_id = -1;
 237        assigned_dev->irq_requested_type &= ~(KVM_DEV_IRQ_GUEST_MASK);
 238}
 239
 240/* The function implicit hold kvm->lock mutex due to cancel_work_sync() */
 241static void deassign_host_irq(struct kvm *kvm,
 242                              struct kvm_assigned_dev_kernel *assigned_dev)
 243{
 244        /*
 245         * We disable irq here to prevent further events.
 246         *
 247         * Notice this maybe result in nested disable if the interrupt type is
 248         * INTx, but it's OK for we are going to free it.
 249         *
 250         * If this function is a part of VM destroy, please ensure that till
 251         * now, the kvm state is still legal for probably we also have to wait
 252         * on a currently running IRQ handler.
 253         */
 254        if (assigned_dev->irq_requested_type & KVM_DEV_IRQ_HOST_MSIX) {
 255                int i;
 256                for (i = 0; i < assigned_dev->entries_nr; i++)
 257                        disable_irq(assigned_dev->host_msix_entries[i].vector);
 258
 259                for (i = 0; i < assigned_dev->entries_nr; i++)
 260                        free_irq(assigned_dev->host_msix_entries[i].vector,
 261                                 assigned_dev);
 262
 263                assigned_dev->entries_nr = 0;
 264                kfree(assigned_dev->host_msix_entries);
 265                kfree(assigned_dev->guest_msix_entries);
 266                pci_disable_msix(assigned_dev->dev);
 267        } else {
 268                /* Deal with MSI and INTx */
 269                if ((assigned_dev->irq_requested_type &
 270                     KVM_DEV_IRQ_HOST_INTX) &&
 271                    (assigned_dev->flags & KVM_DEV_ASSIGN_PCI_2_3)) {
 272                        spin_lock_irq(&assigned_dev->intx_lock);
 273                        pci_intx(assigned_dev->dev, false);
 274                        spin_unlock_irq(&assigned_dev->intx_lock);
 275                        synchronize_irq(assigned_dev->host_irq);
 276                } else
 277                        disable_irq(assigned_dev->host_irq);
 278
 279                free_irq(assigned_dev->host_irq, assigned_dev);
 280
 281                if (assigned_dev->irq_requested_type & KVM_DEV_IRQ_HOST_MSI)
 282                        pci_disable_msi(assigned_dev->dev);
 283        }
 284
 285        assigned_dev->irq_requested_type &= ~(KVM_DEV_IRQ_HOST_MASK);
 286}
 287
 288static int kvm_deassign_irq(struct kvm *kvm,
 289                            struct kvm_assigned_dev_kernel *assigned_dev,
 290                            unsigned long irq_requested_type)
 291{
 292        unsigned long guest_irq_type, host_irq_type;
 293
 294        if (!irqchip_in_kernel(kvm))
 295                return -EINVAL;
 296        /* no irq assignment to deassign */
 297        if (!assigned_dev->irq_requested_type)
 298                return -ENXIO;
 299
 300        host_irq_type = irq_requested_type & KVM_DEV_IRQ_HOST_MASK;
 301        guest_irq_type = irq_requested_type & KVM_DEV_IRQ_GUEST_MASK;
 302
 303        if (host_irq_type)
 304                deassign_host_irq(kvm, assigned_dev);
 305        if (guest_irq_type)
 306                deassign_guest_irq(kvm, assigned_dev);
 307
 308        return 0;
 309}
 310
 311static void kvm_free_assigned_irq(struct kvm *kvm,
 312                                  struct kvm_assigned_dev_kernel *assigned_dev)
 313{
 314        kvm_deassign_irq(kvm, assigned_dev, assigned_dev->irq_requested_type);
 315}
 316
 317static void kvm_free_assigned_device(struct kvm *kvm,
 318                                     struct kvm_assigned_dev_kernel
 319                                     *assigned_dev)
 320{
 321        kvm_free_assigned_irq(kvm, assigned_dev);
 322
 323        pci_reset_function(assigned_dev->dev);
 324        if (pci_load_and_free_saved_state(assigned_dev->dev,
 325                                          &assigned_dev->pci_saved_state))
 326                printk(KERN_INFO "%s: Couldn't reload %s saved state\n",
 327                       __func__, dev_name(&assigned_dev->dev->dev));
 328        else
 329                pci_restore_state(assigned_dev->dev);
 330
 331        pci_clear_dev_assigned(assigned_dev->dev);
 332
 333        pci_release_regions(assigned_dev->dev);
 334        pci_disable_device(assigned_dev->dev);
 335        pci_dev_put(assigned_dev->dev);
 336
 337        list_del(&assigned_dev->list);
 338        kfree(assigned_dev);
 339}
 340
 341void kvm_free_all_assigned_devices(struct kvm *kvm)
 342{
 343        struct list_head *ptr, *ptr2;
 344        struct kvm_assigned_dev_kernel *assigned_dev;
 345
 346        list_for_each_safe(ptr, ptr2, &kvm->arch.assigned_dev_head) {
 347                assigned_dev = list_entry(ptr,
 348                                          struct kvm_assigned_dev_kernel,
 349                                          list);
 350
 351                kvm_free_assigned_device(kvm, assigned_dev);
 352        }
 353}
 354
 355static int assigned_device_enable_host_intx(struct kvm *kvm,
 356                                            struct kvm_assigned_dev_kernel *dev)
 357{
 358        irq_handler_t irq_handler;
 359        unsigned long flags;
 360
 361        dev->host_irq = dev->dev->irq;
 362
 363        /*
 364         * We can only share the IRQ line with other host devices if we are
 365         * able to disable the IRQ source at device-level - independently of
 366         * the guest driver. Otherwise host devices may suffer from unbounded
 367         * IRQ latencies when the guest keeps the line asserted.
 368         */
 369        if (dev->flags & KVM_DEV_ASSIGN_PCI_2_3) {
 370                irq_handler = kvm_assigned_dev_intx;
 371                flags = IRQF_SHARED;
 372        } else {
 373                irq_handler = NULL;
 374                flags = IRQF_ONESHOT;
 375        }
 376        if (request_threaded_irq(dev->host_irq, irq_handler,
 377                                 kvm_assigned_dev_thread_intx, flags,
 378                                 dev->irq_name, dev))
 379                return -EIO;
 380
 381        if (dev->flags & KVM_DEV_ASSIGN_PCI_2_3) {
 382                spin_lock_irq(&dev->intx_lock);
 383                pci_intx(dev->dev, true);
 384                spin_unlock_irq(&dev->intx_lock);
 385        }
 386        return 0;
 387}
 388
 389#ifdef __KVM_HAVE_MSI
 390static int assigned_device_enable_host_msi(struct kvm *kvm,
 391                                           struct kvm_assigned_dev_kernel *dev)
 392{
 393        int r;
 394
 395        if (!dev->dev->msi_enabled) {
 396                r = pci_enable_msi(dev->dev);
 397                if (r)
 398                        return r;
 399        }
 400
 401        dev->host_irq = dev->dev->irq;
 402        if (request_threaded_irq(dev->host_irq, kvm_assigned_dev_msi,
 403                                 kvm_assigned_dev_thread_msi, 0,
 404                                 dev->irq_name, dev)) {
 405                pci_disable_msi(dev->dev);
 406                return -EIO;
 407        }
 408
 409        return 0;
 410}
 411#endif
 412
 413#ifdef __KVM_HAVE_MSIX
 414static int assigned_device_enable_host_msix(struct kvm *kvm,
 415                                            struct kvm_assigned_dev_kernel *dev)
 416{
 417        int i, r = -EINVAL;
 418
 419        /* host_msix_entries and guest_msix_entries should have been
 420         * initialized */
 421        if (dev->entries_nr == 0)
 422                return r;
 423
 424        r = pci_enable_msix_exact(dev->dev,
 425                                  dev->host_msix_entries, dev->entries_nr);
 426        if (r)
 427                return r;
 428
 429        for (i = 0; i < dev->entries_nr; i++) {
 430                r = request_threaded_irq(dev->host_msix_entries[i].vector,
 431                                         kvm_assigned_dev_msix,
 432                                         kvm_assigned_dev_thread_msix,
 433                                         0, dev->irq_name, dev);
 434                if (r)
 435                        goto err;
 436        }
 437
 438        return 0;
 439err:
 440        for (i -= 1; i >= 0; i--)
 441                free_irq(dev->host_msix_entries[i].vector, dev);
 442        pci_disable_msix(dev->dev);
 443        return r;
 444}
 445
 446#endif
 447
 448static int assigned_device_enable_guest_intx(struct kvm *kvm,
 449                                struct kvm_assigned_dev_kernel *dev,
 450                                struct kvm_assigned_irq *irq)
 451{
 452        dev->guest_irq = irq->guest_irq;
 453        dev->ack_notifier.gsi = irq->guest_irq;
 454        return 0;
 455}
 456
 457#ifdef __KVM_HAVE_MSI
 458static int assigned_device_enable_guest_msi(struct kvm *kvm,
 459                        struct kvm_assigned_dev_kernel *dev,
 460                        struct kvm_assigned_irq *irq)
 461{
 462        dev->guest_irq = irq->guest_irq;
 463        dev->ack_notifier.gsi = -1;
 464        return 0;
 465}
 466#endif
 467
 468#ifdef __KVM_HAVE_MSIX
 469static int assigned_device_enable_guest_msix(struct kvm *kvm,
 470                        struct kvm_assigned_dev_kernel *dev,
 471                        struct kvm_assigned_irq *irq)
 472{
 473        dev->guest_irq = irq->guest_irq;
 474        dev->ack_notifier.gsi = -1;
 475        return 0;
 476}
 477#endif
 478
 479static int assign_host_irq(struct kvm *kvm,
 480                           struct kvm_assigned_dev_kernel *dev,
 481                           __u32 host_irq_type)
 482{
 483        int r = -EEXIST;
 484
 485        if (dev->irq_requested_type & KVM_DEV_IRQ_HOST_MASK)
 486                return r;
 487
 488        snprintf(dev->irq_name, sizeof(dev->irq_name), "kvm:%s",
 489                 pci_name(dev->dev));
 490
 491        switch (host_irq_type) {
 492        case KVM_DEV_IRQ_HOST_INTX:
 493                r = assigned_device_enable_host_intx(kvm, dev);
 494                break;
 495#ifdef __KVM_HAVE_MSI
 496        case KVM_DEV_IRQ_HOST_MSI:
 497                r = assigned_device_enable_host_msi(kvm, dev);
 498                break;
 499#endif
 500#ifdef __KVM_HAVE_MSIX
 501        case KVM_DEV_IRQ_HOST_MSIX:
 502                r = assigned_device_enable_host_msix(kvm, dev);
 503                break;
 504#endif
 505        default:
 506                r = -EINVAL;
 507        }
 508        dev->host_irq_disabled = false;
 509
 510        if (!r)
 511                dev->irq_requested_type |= host_irq_type;
 512
 513        return r;
 514}
 515
 516static int assign_guest_irq(struct kvm *kvm,
 517                            struct kvm_assigned_dev_kernel *dev,
 518                            struct kvm_assigned_irq *irq,
 519                            unsigned long guest_irq_type)
 520{
 521        int id;
 522        int r = -EEXIST;
 523
 524        if (dev->irq_requested_type & KVM_DEV_IRQ_GUEST_MASK)
 525                return r;
 526
 527        id = kvm_request_irq_source_id(kvm);
 528        if (id < 0)
 529                return id;
 530
 531        dev->irq_source_id = id;
 532
 533        switch (guest_irq_type) {
 534        case KVM_DEV_IRQ_GUEST_INTX:
 535                r = assigned_device_enable_guest_intx(kvm, dev, irq);
 536                break;
 537#ifdef __KVM_HAVE_MSI
 538        case KVM_DEV_IRQ_GUEST_MSI:
 539                r = assigned_device_enable_guest_msi(kvm, dev, irq);
 540                break;
 541#endif
 542#ifdef __KVM_HAVE_MSIX
 543        case KVM_DEV_IRQ_GUEST_MSIX:
 544                r = assigned_device_enable_guest_msix(kvm, dev, irq);
 545                break;
 546#endif
 547        default:
 548                r = -EINVAL;
 549        }
 550
 551        if (!r) {
 552                dev->irq_requested_type |= guest_irq_type;
 553                if (dev->ack_notifier.gsi != -1)
 554                        kvm_register_irq_ack_notifier(kvm, &dev->ack_notifier);
 555        } else {
 556                kvm_free_irq_source_id(kvm, dev->irq_source_id);
 557                dev->irq_source_id = -1;
 558        }
 559
 560        return r;
 561}
 562
 563/* TODO Deal with KVM_DEV_IRQ_ASSIGNED_MASK_MSIX */
 564static int kvm_vm_ioctl_assign_irq(struct kvm *kvm,
 565                                   struct kvm_assigned_irq *assigned_irq)
 566{
 567        int r = -EINVAL;
 568        struct kvm_assigned_dev_kernel *match;
 569        unsigned long host_irq_type, guest_irq_type;
 570
 571        if (!irqchip_in_kernel(kvm))
 572                return r;
 573
 574        mutex_lock(&kvm->lock);
 575        r = -ENODEV;
 576        match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
 577                                      assigned_irq->assigned_dev_id);
 578        if (!match)
 579                goto out;
 580
 581        host_irq_type = (assigned_irq->flags & KVM_DEV_IRQ_HOST_MASK);
 582        guest_irq_type = (assigned_irq->flags & KVM_DEV_IRQ_GUEST_MASK);
 583
 584        r = -EINVAL;
 585        /* can only assign one type at a time */
 586        if (hweight_long(host_irq_type) > 1)
 587                goto out;
 588        if (hweight_long(guest_irq_type) > 1)
 589                goto out;
 590        if (host_irq_type == 0 && guest_irq_type == 0)
 591                goto out;
 592
 593        r = 0;
 594        if (host_irq_type)
 595                r = assign_host_irq(kvm, match, host_irq_type);
 596        if (r)
 597                goto out;
 598
 599        if (guest_irq_type)
 600                r = assign_guest_irq(kvm, match, assigned_irq, guest_irq_type);
 601out:
 602        mutex_unlock(&kvm->lock);
 603        return r;
 604}
 605
 606static int kvm_vm_ioctl_deassign_dev_irq(struct kvm *kvm,
 607                                         struct kvm_assigned_irq
 608                                         *assigned_irq)
 609{
 610        int r = -ENODEV;
 611        struct kvm_assigned_dev_kernel *match;
 612        unsigned long irq_type;
 613
 614        mutex_lock(&kvm->lock);
 615
 616        match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
 617                                      assigned_irq->assigned_dev_id);
 618        if (!match)
 619                goto out;
 620
 621        irq_type = assigned_irq->flags & (KVM_DEV_IRQ_HOST_MASK |
 622                                          KVM_DEV_IRQ_GUEST_MASK);
 623        r = kvm_deassign_irq(kvm, match, irq_type);
 624out:
 625        mutex_unlock(&kvm->lock);
 626        return r;
 627}
 628
 629/*
 630 * We want to test whether the caller has been granted permissions to
 631 * use this device.  To be able to configure and control the device,
 632 * the user needs access to PCI configuration space and BAR resources.
 633 * These are accessed through PCI sysfs.  PCI config space is often
 634 * passed to the process calling this ioctl via file descriptor, so we
 635 * can't rely on access to that file.  We can check for permissions
 636 * on each of the BAR resource files, which is a pretty clear
 637 * indicator that the user has been granted access to the device.
 638 */
 639static int probe_sysfs_permissions(struct pci_dev *dev)
 640{
 641#ifdef CONFIG_SYSFS
 642        int i;
 643        bool bar_found = false;
 644
 645        for (i = PCI_STD_RESOURCES; i <= PCI_STD_RESOURCE_END; i++) {
 646                char *kpath, *syspath;
 647                struct path path;
 648                struct inode *inode;
 649                int r;
 650
 651                if (!pci_resource_len(dev, i))
 652                        continue;
 653
 654                kpath = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
 655                if (!kpath)
 656                        return -ENOMEM;
 657
 658                /* Per sysfs-rules, sysfs is always at /sys */
 659                syspath = kasprintf(GFP_KERNEL, "/sys%s/resource%d", kpath, i);
 660                kfree(kpath);
 661                if (!syspath)
 662                        return -ENOMEM;
 663
 664                r = kern_path(syspath, LOOKUP_FOLLOW, &path);
 665                kfree(syspath);
 666                if (r)
 667                        return r;
 668
 669                inode = path.dentry->d_inode;
 670
 671                r = inode_permission(inode, MAY_READ | MAY_WRITE | MAY_ACCESS);
 672                path_put(&path);
 673                if (r)
 674                        return r;
 675
 676                bar_found = true;
 677        }
 678
 679        /* If no resources, probably something special */
 680        if (!bar_found)
 681                return -EPERM;
 682
 683        return 0;
 684#else
 685        return -EINVAL; /* No way to control the device without sysfs */
 686#endif
 687}
 688
 689static int kvm_vm_ioctl_assign_device(struct kvm *kvm,
 690                                      struct kvm_assigned_pci_dev *assigned_dev)
 691{
 692        int r = 0, idx;
 693        struct kvm_assigned_dev_kernel *match;
 694        struct pci_dev *dev;
 695
 696        if (!(assigned_dev->flags & KVM_DEV_ASSIGN_ENABLE_IOMMU))
 697                return -EINVAL;
 698
 699        mutex_lock(&kvm->lock);
 700        idx = srcu_read_lock(&kvm->srcu);
 701
 702        match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
 703                                      assigned_dev->assigned_dev_id);
 704        if (match) {
 705                /* device already assigned */
 706                r = -EEXIST;
 707                goto out;
 708        }
 709
 710        match = kzalloc(sizeof(struct kvm_assigned_dev_kernel), GFP_KERNEL);
 711        if (match == NULL) {
 712                printk(KERN_INFO "%s: Couldn't allocate memory\n",
 713                       __func__);
 714                r = -ENOMEM;
 715                goto out;
 716        }
 717        dev = pci_get_domain_bus_and_slot(assigned_dev->segnr,
 718                                   assigned_dev->busnr,
 719                                   assigned_dev->devfn);
 720        if (!dev) {
 721                printk(KERN_INFO "%s: host device not found\n", __func__);
 722                r = -EINVAL;
 723                goto out_free;
 724        }
 725
 726        /* Don't allow bridges to be assigned */
 727        if (dev->hdr_type != PCI_HEADER_TYPE_NORMAL) {
 728                r = -EPERM;
 729                goto out_put;
 730        }
 731
 732        r = probe_sysfs_permissions(dev);
 733        if (r)
 734                goto out_put;
 735
 736        if (pci_enable_device(dev)) {
 737                printk(KERN_INFO "%s: Could not enable PCI device\n", __func__);
 738                r = -EBUSY;
 739                goto out_put;
 740        }
 741        r = pci_request_regions(dev, "kvm_assigned_device");
 742        if (r) {
 743                printk(KERN_INFO "%s: Could not get access to device regions\n",
 744                       __func__);
 745                goto out_disable;
 746        }
 747
 748        pci_reset_function(dev);
 749        pci_save_state(dev);
 750        match->pci_saved_state = pci_store_saved_state(dev);
 751        if (!match->pci_saved_state)
 752                printk(KERN_DEBUG "%s: Couldn't store %s saved state\n",
 753                       __func__, dev_name(&dev->dev));
 754
 755        if (!pci_intx_mask_supported(dev))
 756                assigned_dev->flags &= ~KVM_DEV_ASSIGN_PCI_2_3;
 757
 758        match->assigned_dev_id = assigned_dev->assigned_dev_id;
 759        match->host_segnr = assigned_dev->segnr;
 760        match->host_busnr = assigned_dev->busnr;
 761        match->host_devfn = assigned_dev->devfn;
 762        match->flags = assigned_dev->flags;
 763        match->dev = dev;
 764        spin_lock_init(&match->intx_lock);
 765        spin_lock_init(&match->intx_mask_lock);
 766        match->irq_source_id = -1;
 767        match->kvm = kvm;
 768        match->ack_notifier.irq_acked = kvm_assigned_dev_ack_irq;
 769
 770        list_add(&match->list, &kvm->arch.assigned_dev_head);
 771
 772        if (!kvm->arch.iommu_domain) {
 773                r = kvm_iommu_map_guest(kvm);
 774                if (r)
 775                        goto out_list_del;
 776        }
 777        r = kvm_assign_device(kvm, match->dev);
 778        if (r)
 779                goto out_list_del;
 780
 781out:
 782        srcu_read_unlock(&kvm->srcu, idx);
 783        mutex_unlock(&kvm->lock);
 784        return r;
 785out_list_del:
 786        if (pci_load_and_free_saved_state(dev, &match->pci_saved_state))
 787                printk(KERN_INFO "%s: Couldn't reload %s saved state\n",
 788                       __func__, dev_name(&dev->dev));
 789        list_del(&match->list);
 790        pci_release_regions(dev);
 791out_disable:
 792        pci_disable_device(dev);
 793out_put:
 794        pci_dev_put(dev);
 795out_free:
 796        kfree(match);
 797        srcu_read_unlock(&kvm->srcu, idx);
 798        mutex_unlock(&kvm->lock);
 799        return r;
 800}
 801
 802static int kvm_vm_ioctl_deassign_device(struct kvm *kvm,
 803                struct kvm_assigned_pci_dev *assigned_dev)
 804{
 805        int r = 0;
 806        struct kvm_assigned_dev_kernel *match;
 807
 808        mutex_lock(&kvm->lock);
 809
 810        match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
 811                                      assigned_dev->assigned_dev_id);
 812        if (!match) {
 813                printk(KERN_INFO "%s: device hasn't been assigned before, "
 814                  "so cannot be deassigned\n", __func__);
 815                r = -EINVAL;
 816                goto out;
 817        }
 818
 819        kvm_deassign_device(kvm, match->dev);
 820
 821        kvm_free_assigned_device(kvm, match);
 822
 823out:
 824        mutex_unlock(&kvm->lock);
 825        return r;
 826}
 827
 828
 829#ifdef __KVM_HAVE_MSIX
 830static int kvm_vm_ioctl_set_msix_nr(struct kvm *kvm,
 831                                    struct kvm_assigned_msix_nr *entry_nr)
 832{
 833        int r = 0;
 834        struct kvm_assigned_dev_kernel *adev;
 835
 836        mutex_lock(&kvm->lock);
 837
 838        adev = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
 839                                      entry_nr->assigned_dev_id);
 840        if (!adev) {
 841                r = -EINVAL;
 842                goto msix_nr_out;
 843        }
 844
 845        if (adev->entries_nr == 0) {
 846                adev->entries_nr = entry_nr->entry_nr;
 847                if (adev->entries_nr == 0 ||
 848                    adev->entries_nr > KVM_MAX_MSIX_PER_DEV) {
 849                        r = -EINVAL;
 850                        goto msix_nr_out;
 851                }
 852
 853                adev->host_msix_entries = kzalloc(sizeof(struct msix_entry) *
 854                                                entry_nr->entry_nr,
 855                                                GFP_KERNEL);
 856                if (!adev->host_msix_entries) {
 857                        r = -ENOMEM;
 858                        goto msix_nr_out;
 859                }
 860                adev->guest_msix_entries =
 861                        kzalloc(sizeof(struct msix_entry) * entry_nr->entry_nr,
 862                                GFP_KERNEL);
 863                if (!adev->guest_msix_entries) {
 864                        kfree(adev->host_msix_entries);
 865                        r = -ENOMEM;
 866                        goto msix_nr_out;
 867                }
 868        } else /* Not allowed set MSI-X number twice */
 869                r = -EINVAL;
 870msix_nr_out:
 871        mutex_unlock(&kvm->lock);
 872        return r;
 873}
 874
 875static int kvm_vm_ioctl_set_msix_entry(struct kvm *kvm,
 876                                       struct kvm_assigned_msix_entry *entry)
 877{
 878        int r = 0, i;
 879        struct kvm_assigned_dev_kernel *adev;
 880
 881        mutex_lock(&kvm->lock);
 882
 883        adev = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
 884                                      entry->assigned_dev_id);
 885
 886        if (!adev) {
 887                r = -EINVAL;
 888                goto msix_entry_out;
 889        }
 890
 891        for (i = 0; i < adev->entries_nr; i++)
 892                if (adev->guest_msix_entries[i].vector == 0 ||
 893                    adev->guest_msix_entries[i].entry == entry->entry) {
 894                        adev->guest_msix_entries[i].entry = entry->entry;
 895                        adev->guest_msix_entries[i].vector = entry->gsi;
 896                        adev->host_msix_entries[i].entry = entry->entry;
 897                        break;
 898                }
 899        if (i == adev->entries_nr) {
 900                r = -ENOSPC;
 901                goto msix_entry_out;
 902        }
 903
 904msix_entry_out:
 905        mutex_unlock(&kvm->lock);
 906
 907        return r;
 908}
 909#endif
 910
 911static int kvm_vm_ioctl_set_pci_irq_mask(struct kvm *kvm,
 912                struct kvm_assigned_pci_dev *assigned_dev)
 913{
 914        int r = 0;
 915        struct kvm_assigned_dev_kernel *match;
 916
 917        mutex_lock(&kvm->lock);
 918
 919        match = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head,
 920                                      assigned_dev->assigned_dev_id);
 921        if (!match) {
 922                r = -ENODEV;
 923                goto out;
 924        }
 925
 926        spin_lock(&match->intx_mask_lock);
 927
 928        match->flags &= ~KVM_DEV_ASSIGN_MASK_INTX;
 929        match->flags |= assigned_dev->flags & KVM_DEV_ASSIGN_MASK_INTX;
 930
 931        if (match->irq_requested_type & KVM_DEV_IRQ_GUEST_INTX) {
 932                if (assigned_dev->flags & KVM_DEV_ASSIGN_MASK_INTX) {
 933                        kvm_set_irq(match->kvm, match->irq_source_id,
 934                                    match->guest_irq, 0, false);
 935                        /*
 936                         * Masking at hardware-level is performed on demand,
 937                         * i.e. when an IRQ actually arrives at the host.
 938                         */
 939                } else if (!(assigned_dev->flags & KVM_DEV_ASSIGN_PCI_2_3)) {
 940                        /*
 941                         * Unmask the IRQ line if required. Unmasking at
 942                         * device level will be performed by user space.
 943                         */
 944                        spin_lock_irq(&match->intx_lock);
 945                        if (match->host_irq_disabled) {
 946                                enable_irq(match->host_irq);
 947                                match->host_irq_disabled = false;
 948                        }
 949                        spin_unlock_irq(&match->intx_lock);
 950                }
 951        }
 952
 953        spin_unlock(&match->intx_mask_lock);
 954
 955out:
 956        mutex_unlock(&kvm->lock);
 957        return r;
 958}
 959
 960long kvm_vm_ioctl_assigned_device(struct kvm *kvm, unsigned ioctl,
 961                                  unsigned long arg)
 962{
 963        void __user *argp = (void __user *)arg;
 964        int r;
 965
 966        switch (ioctl) {
 967        case KVM_ASSIGN_PCI_DEVICE: {
 968                struct kvm_assigned_pci_dev assigned_dev;
 969
 970                r = -EFAULT;
 971                if (copy_from_user(&assigned_dev, argp, sizeof assigned_dev))
 972                        goto out;
 973                r = kvm_vm_ioctl_assign_device(kvm, &assigned_dev);
 974                if (r)
 975                        goto out;
 976                break;
 977        }
 978        case KVM_ASSIGN_IRQ: {
 979                r = -EOPNOTSUPP;
 980                break;
 981        }
 982        case KVM_ASSIGN_DEV_IRQ: {
 983                struct kvm_assigned_irq assigned_irq;
 984
 985                r = -EFAULT;
 986                if (copy_from_user(&assigned_irq, argp, sizeof assigned_irq))
 987                        goto out;
 988                r = kvm_vm_ioctl_assign_irq(kvm, &assigned_irq);
 989                if (r)
 990                        goto out;
 991                break;
 992        }
 993        case KVM_DEASSIGN_DEV_IRQ: {
 994                struct kvm_assigned_irq assigned_irq;
 995
 996                r = -EFAULT;
 997                if (copy_from_user(&assigned_irq, argp, sizeof assigned_irq))
 998                        goto out;
 999                r = kvm_vm_ioctl_deassign_dev_irq(kvm, &assigned_irq);
1000                if (r)
1001                        goto out;
1002                break;
1003        }
1004        case KVM_DEASSIGN_PCI_DEVICE: {
1005                struct kvm_assigned_pci_dev assigned_dev;
1006
1007                r = -EFAULT;
1008                if (copy_from_user(&assigned_dev, argp, sizeof assigned_dev))
1009                        goto out;
1010                r = kvm_vm_ioctl_deassign_device(kvm, &assigned_dev);
1011                if (r)
1012                        goto out;
1013                break;
1014        }
1015#ifdef __KVM_HAVE_MSIX
1016        case KVM_ASSIGN_SET_MSIX_NR: {
1017                struct kvm_assigned_msix_nr entry_nr;
1018                r = -EFAULT;
1019                if (copy_from_user(&entry_nr, argp, sizeof entry_nr))
1020                        goto out;
1021                r = kvm_vm_ioctl_set_msix_nr(kvm, &entry_nr);
1022                if (r)
1023                        goto out;
1024                break;
1025        }
1026        case KVM_ASSIGN_SET_MSIX_ENTRY: {
1027                struct kvm_assigned_msix_entry entry;
1028                r = -EFAULT;
1029                if (copy_from_user(&entry, argp, sizeof entry))
1030                        goto out;
1031                r = kvm_vm_ioctl_set_msix_entry(kvm, &entry);
1032                if (r)
1033                        goto out;
1034                break;
1035        }
1036#endif
1037        case KVM_ASSIGN_SET_INTX_MASK: {
1038                struct kvm_assigned_pci_dev assigned_dev;
1039
1040                r = -EFAULT;
1041                if (copy_from_user(&assigned_dev, argp, sizeof assigned_dev))
1042                        goto out;
1043                r = kvm_vm_ioctl_set_pci_irq_mask(kvm, &assigned_dev);
1044                break;
1045        }
1046        default:
1047                r = -ENOTTY;
1048                break;
1049        }
1050out:
1051        return r;
1052}
1053