TOMOYO Linux Cross Reference
Linux/virt/kvm/kvm_main.c

   /*
    * Kernel-based Virtual Machine driver for Linux
    *
    * This module enables machines with Intel VT-x extensions to run virtual
    * machines without emulation or binary translation.
    *
    * Copyright (C) 2006 Qumranet, Inc.
    * Copyright 2010 Red Hat, Inc. and/or its affiliates.
    *
   * Authors:
   *   Avi Kivity   <avi@qumranet.com>
   *   Yaniv Kamay  <yaniv@qumranet.com>
   *
   * This work is licensed under the terms of the GNU GPL, version 2.  See
   * the COPYING file in the top-level directory.
   *
   */
  
  #include <kvm/iodev.h>
  
  #include <linux/kvm_host.h>
  #include <linux/kvm.h>
  #include <linux/module.h>
  #include <linux/errno.h>
  #include <linux/percpu.h>
  #include <linux/mm.h>
  #include <linux/miscdevice.h>
  #include <linux/vmalloc.h>
  #include <linux/reboot.h>
  #include <linux/debugfs.h>
  #include <linux/highmem.h>
  #include <linux/file.h>
  #include <linux/syscore_ops.h>
  #include <linux/cpu.h>
  #include <linux/sched/signal.h>
  #include <linux/sched/mm.h>
  #include <linux/sched/stat.h>
  #include <linux/cpumask.h>
  #include <linux/smp.h>
  #include <linux/anon_inodes.h>
  #include <linux/profile.h>
  #include <linux/kvm_para.h>
  #include <linux/pagemap.h>
  #include <linux/mman.h>
  #include <linux/swap.h>
  #include <linux/bitops.h>
  #include <linux/spinlock.h>
  #include <linux/compat.h>
  #include <linux/srcu.h>
  #include <linux/hugetlb.h>
  #include <linux/slab.h>
  #include <linux/sort.h>
  #include <linux/bsearch.h>
  
  #include <asm/processor.h>
  #include <asm/io.h>
  #include <asm/ioctl.h>
  #include <linux/uaccess.h>
  #include <asm/pgtable.h>
  
  #include "coalesced_mmio.h"
  #include "async_pf.h"
  #include "vfio.h"
  
  #define CREATE_TRACE_POINTS
  #include <trace/events/kvm.h>
  
  /* Worst case buffer size needed for holding an integer. */
  #define ITOA_MAX_LEN 12
  
  MODULE_AUTHOR("Qumranet");
  MODULE_LICENSE("GPL");
  
  /* Architectures should define their poll value according to the halt latency */
  unsigned int halt_poll_ns = KVM_HALT_POLL_NS_DEFAULT;
  module_param(halt_poll_ns, uint, 0644);
  EXPORT_SYMBOL_GPL(halt_poll_ns);
  
  /* Default doubles per-vcpu halt_poll_ns. */
  unsigned int halt_poll_ns_grow = 2;
  module_param(halt_poll_ns_grow, uint, 0644);
  EXPORT_SYMBOL_GPL(halt_poll_ns_grow);
  
  /* Default resets per-vcpu halt_poll_ns . */
  unsigned int halt_poll_ns_shrink;
  module_param(halt_poll_ns_shrink, uint, 0644);
  EXPORT_SYMBOL_GPL(halt_poll_ns_shrink);
  
  /*
   * Ordering of locks:
   *
   *      kvm->lock --> kvm->slots_lock --> kvm->irq_lock
   */
  
  DEFINE_SPINLOCK(kvm_lock);
  static DEFINE_RAW_SPINLOCK(kvm_count_lock);
  LIST_HEAD(vm_list);
  
  static cpumask_var_t cpus_hardware_enabled;
 static int kvm_usage_count;
 static atomic_t hardware_enable_failed;
 
 struct kmem_cache *kvm_vcpu_cache;
 EXPORT_SYMBOL_GPL(kvm_vcpu_cache);
 
 static __read_mostly struct preempt_ops kvm_preempt_ops;
 
 struct dentry *kvm_debugfs_dir;
 EXPORT_SYMBOL_GPL(kvm_debugfs_dir);
 
 static int kvm_debugfs_num_entries;
 static const struct file_operations *stat_fops_per_vm[];
 
 static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
                            unsigned long arg);
 #ifdef CONFIG_KVM_COMPAT
 static long kvm_vcpu_compat_ioctl(struct file *file, unsigned int ioctl,
                                   unsigned long arg);
 #define KVM_COMPAT(c)   .compat_ioctl   = (c)
 #else
 static long kvm_no_compat_ioctl(struct file *file, unsigned int ioctl,
                                 unsigned long arg) { return -EINVAL; }
 #define KVM_COMPAT(c)   .compat_ioctl   = kvm_no_compat_ioctl
 #endif
 static int hardware_enable_all(void);
 static void hardware_disable_all(void);
 
 static void kvm_io_bus_destroy(struct kvm_io_bus *bus);
 
 static void mark_page_dirty_in_slot(struct kvm_memory_slot *memslot, gfn_t gfn);
 
 __visible bool kvm_rebooting;
 EXPORT_SYMBOL_GPL(kvm_rebooting);
 
 static bool largepages_enabled = true;
 
 #define KVM_EVENT_CREATE_VM 0
 #define KVM_EVENT_DESTROY_VM 1
 static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm);
 static unsigned long long kvm_createvm_count;
 static unsigned long long kvm_active_vms;
 
 __weak int kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
                 unsigned long start, unsigned long end, bool blockable)
 {
         return 0;
 }
 
 bool kvm_is_reserved_pfn(kvm_pfn_t pfn)
 {
         if (pfn_valid(pfn))
                 return PageReserved(pfn_to_page(pfn));
 
         return true;
 }
 
 /*
  * Switches to specified vcpu, until a matching vcpu_put()
  */
 void vcpu_load(struct kvm_vcpu *vcpu)
 {
         int cpu = get_cpu();
         preempt_notifier_register(&vcpu->preempt_notifier);
         kvm_arch_vcpu_load(vcpu, cpu);
         put_cpu();
 }
 EXPORT_SYMBOL_GPL(vcpu_load);
 
 void vcpu_put(struct kvm_vcpu *vcpu)
 {
         preempt_disable();
         kvm_arch_vcpu_put(vcpu);
         preempt_notifier_unregister(&vcpu->preempt_notifier);
         preempt_enable();
 }
 EXPORT_SYMBOL_GPL(vcpu_put);
 
 /* TODO: merge with kvm_arch_vcpu_should_kick */
 static bool kvm_request_needs_ipi(struct kvm_vcpu *vcpu, unsigned req)
 {
         int mode = kvm_vcpu_exiting_guest_mode(vcpu);
 
         /*
          * We need to wait for the VCPU to reenable interrupts and get out of
          * READING_SHADOW_PAGE_TABLES mode.
          */
         if (req & KVM_REQUEST_WAIT)
                 return mode != OUTSIDE_GUEST_MODE;
 
         /*
          * Need to kick a running VCPU, but otherwise there is nothing to do.
          */
         return mode == IN_GUEST_MODE;
 }
 
 static void ack_flush(void *_completed)
 {
 }
 
 static inline bool kvm_kick_many_cpus(const struct cpumask *cpus, bool wait)
 {
         if (unlikely(!cpus))
                 cpus = cpu_online_mask;
 
         if (cpumask_empty(cpus))
                 return false;
 
         smp_call_function_many(cpus, ack_flush, NULL, wait);
         return true;
 }
 
 bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
                                  unsigned long *vcpu_bitmap, cpumask_var_t tmp)
 {
         int i, cpu, me;
         struct kvm_vcpu *vcpu;
         bool called;
 
         me = get_cpu();
 
         kvm_for_each_vcpu(i, vcpu, kvm) {
                 if (vcpu_bitmap && !test_bit(i, vcpu_bitmap))
                         continue;
 
                 kvm_make_request(req, vcpu);
                 cpu = vcpu->cpu;
 
                 if (!(req & KVM_REQUEST_NO_WAKEUP) && kvm_vcpu_wake_up(vcpu))
                         continue;
 
                 if (tmp != NULL && cpu != -1 && cpu != me &&
                     kvm_request_needs_ipi(vcpu, req))
                         __cpumask_set_cpu(cpu, tmp);
         }
 
         called = kvm_kick_many_cpus(tmp, !!(req & KVM_REQUEST_WAIT));
         put_cpu();
 
         return called;
 }
 
 bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
 {
         cpumask_var_t cpus;
         bool called;
 
         zalloc_cpumask_var(&cpus, GFP_ATOMIC);
 
         called = kvm_make_vcpus_request_mask(kvm, req, NULL, cpus);
 
         free_cpumask_var(cpus);
         return called;
 }
 
 #ifndef CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL
 void kvm_flush_remote_tlbs(struct kvm *kvm)
 {
         /*
          * Read tlbs_dirty before setting KVM_REQ_TLB_FLUSH in
          * kvm_make_all_cpus_request.
          */
         long dirty_count = smp_load_acquire(&kvm->tlbs_dirty);
 
         /*
          * We want to publish modifications to the page tables before reading
          * mode. Pairs with a memory barrier in arch-specific code.
          * - x86: smp_mb__after_srcu_read_unlock in vcpu_enter_guest
          * and smp_mb in walk_shadow_page_lockless_begin/end.
          * - powerpc: smp_mb in kvmppc_prepare_to_enter.
          *
          * There is already an smp_mb__after_atomic() before
          * kvm_make_all_cpus_request() reads vcpu->mode. We reuse that
          * barrier here.
          */
         if (!kvm_arch_flush_remote_tlb(kvm)
             || kvm_make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH))
                 ++kvm->stat.remote_tlb_flush;
         cmpxchg(&kvm->tlbs_dirty, dirty_count, 0);
 }
 EXPORT_SYMBOL_GPL(kvm_flush_remote_tlbs);
 #endif
 
 void kvm_reload_remote_mmus(struct kvm *kvm)
 {
         kvm_make_all_cpus_request(kvm, KVM_REQ_MMU_RELOAD);
 }
 
 int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
 {
         struct page *page;
         int r;
 
         mutex_init(&vcpu->mutex);
         vcpu->cpu = -1;
         vcpu->kvm = kvm;
         vcpu->vcpu_id = id;
         vcpu->pid = NULL;
         init_swait_queue_head(&vcpu->wq);
         kvm_async_pf_vcpu_init(vcpu);
 
         vcpu->pre_pcpu = -1;
         INIT_LIST_HEAD(&vcpu->blocked_vcpu_list);
 
         page = alloc_page(GFP_KERNEL | __GFP_ZERO);
         if (!page) {
                 r = -ENOMEM;
                 goto fail;
         }
         vcpu->run = page_address(page);
 
         kvm_vcpu_set_in_spin_loop(vcpu, false);
         kvm_vcpu_set_dy_eligible(vcpu, false);
         vcpu->preempted = false;
 
         r = kvm_arch_vcpu_init(vcpu);
         if (r < 0)
                 goto fail_free_run;
         return 0;
 
 fail_free_run:
         free_page((unsigned long)vcpu->run);
 fail:
         return r;
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_init);
 
 void kvm_vcpu_uninit(struct kvm_vcpu *vcpu)
 {
         /*
          * no need for rcu_read_lock as VCPU_RUN is the only place that
          * will change the vcpu->pid pointer and on uninit all file
          * descriptors are already gone.
          */
         put_pid(rcu_dereference_protected(vcpu->pid, 1));
         kvm_arch_vcpu_uninit(vcpu);
         free_page((unsigned long)vcpu->run);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_uninit);
 
 #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
 static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn)
 {
         return container_of(mn, struct kvm, mmu_notifier);
 }
 
 static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn,
                                         struct mm_struct *mm,
                                         unsigned long address,
                                         pte_t pte)
 {
         struct kvm *kvm = mmu_notifier_to_kvm(mn);
         int idx;
 
         idx = srcu_read_lock(&kvm->srcu);
         spin_lock(&kvm->mmu_lock);
         kvm->mmu_notifier_seq++;
 
         if (kvm_set_spte_hva(kvm, address, pte))
                 kvm_flush_remote_tlbs(kvm);
 
         spin_unlock(&kvm->mmu_lock);
         srcu_read_unlock(&kvm->srcu, idx);
 }
 
 static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
                                         const struct mmu_notifier_range *range)
 {
         struct kvm *kvm = mmu_notifier_to_kvm(mn);
         int need_tlb_flush = 0, idx;
         int ret;
 
         idx = srcu_read_lock(&kvm->srcu);
         spin_lock(&kvm->mmu_lock);
         /*
          * The count increase must become visible at unlock time as no
          * spte can be established without taking the mmu_lock and
          * count is also read inside the mmu_lock critical section.
          */
         kvm->mmu_notifier_count++;
         need_tlb_flush = kvm_unmap_hva_range(kvm, range->start, range->end);
         need_tlb_flush |= kvm->tlbs_dirty;
         /* we've to flush the tlb before the pages can be freed */
         if (need_tlb_flush)
                 kvm_flush_remote_tlbs(kvm);
 
         spin_unlock(&kvm->mmu_lock);
 
         ret = kvm_arch_mmu_notifier_invalidate_range(kvm, range->start,
                                         range->end, range->blockable);
 
         srcu_read_unlock(&kvm->srcu, idx);
 
         return ret;
 }
 
 static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,
                                         const struct mmu_notifier_range *range)
 {
         struct kvm *kvm = mmu_notifier_to_kvm(mn);
 
         spin_lock(&kvm->mmu_lock);
         /*
          * This sequence increase will notify the kvm page fault that
          * the page that is going to be mapped in the spte could have
          * been freed.
          */
         kvm->mmu_notifier_seq++;
         smp_wmb();
         /*
          * The above sequence increase must be visible before the
          * below count decrease, which is ensured by the smp_wmb above
          * in conjunction with the smp_rmb in mmu_notifier_retry().
          */
         kvm->mmu_notifier_count--;
         spin_unlock(&kvm->mmu_lock);
 
         BUG_ON(kvm->mmu_notifier_count < 0);
 }
 
 static int kvm_mmu_notifier_clear_flush_young(struct mmu_notifier *mn,
                                               struct mm_struct *mm,
                                               unsigned long start,
                                               unsigned long end)
 {
         struct kvm *kvm = mmu_notifier_to_kvm(mn);
         int young, idx;
 
         idx = srcu_read_lock(&kvm->srcu);
         spin_lock(&kvm->mmu_lock);
 
         young = kvm_age_hva(kvm, start, end);
         if (young)
                 kvm_flush_remote_tlbs(kvm);
 
         spin_unlock(&kvm->mmu_lock);
         srcu_read_unlock(&kvm->srcu, idx);
 
         return young;
 }
 
 static int kvm_mmu_notifier_clear_young(struct mmu_notifier *mn,
                                         struct mm_struct *mm,
                                         unsigned long start,
                                         unsigned long end)
 {
         struct kvm *kvm = mmu_notifier_to_kvm(mn);
         int young, idx;
 
         idx = srcu_read_lock(&kvm->srcu);
         spin_lock(&kvm->mmu_lock);
         /*
          * Even though we do not flush TLB, this will still adversely
          * affect performance on pre-Haswell Intel EPT, where there is
          * no EPT Access Bit to clear so that we have to tear down EPT
          * tables instead. If we find this unacceptable, we can always
          * add a parameter to kvm_age_hva so that it effectively doesn't
          * do anything on clear_young.
          *
          * Also note that currently we never issue secondary TLB flushes
          * from clear_young, leaving this job up to the regular system
          * cadence. If we find this inaccurate, we might come up with a
          * more sophisticated heuristic later.
          */
         young = kvm_age_hva(kvm, start, end);
         spin_unlock(&kvm->mmu_lock);
         srcu_read_unlock(&kvm->srcu, idx);
 
         return young;
 }
 
 static int kvm_mmu_notifier_test_young(struct mmu_notifier *mn,
                                        struct mm_struct *mm,
                                        unsigned long address)
 {
         struct kvm *kvm = mmu_notifier_to_kvm(mn);
         int young, idx;
 
         idx = srcu_read_lock(&kvm->srcu);
         spin_lock(&kvm->mmu_lock);
         young = kvm_test_age_hva(kvm, address);
         spin_unlock(&kvm->mmu_lock);
         srcu_read_unlock(&kvm->srcu, idx);
 
         return young;
 }
 
 static void kvm_mmu_notifier_release(struct mmu_notifier *mn,
                                      struct mm_struct *mm)
 {
         struct kvm *kvm = mmu_notifier_to_kvm(mn);
         int idx;
 
         idx = srcu_read_lock(&kvm->srcu);
         kvm_arch_flush_shadow_all(kvm);
         srcu_read_unlock(&kvm->srcu, idx);
 }
 
 static const struct mmu_notifier_ops kvm_mmu_notifier_ops = {
         .invalidate_range_start = kvm_mmu_notifier_invalidate_range_start,
         .invalidate_range_end   = kvm_mmu_notifier_invalidate_range_end,
         .clear_flush_young      = kvm_mmu_notifier_clear_flush_young,
         .clear_young            = kvm_mmu_notifier_clear_young,
         .test_young             = kvm_mmu_notifier_test_young,
         .change_pte             = kvm_mmu_notifier_change_pte,
         .release                = kvm_mmu_notifier_release,
 };
 
 static int kvm_init_mmu_notifier(struct kvm *kvm)
 {
         kvm->mmu_notifier.ops = &kvm_mmu_notifier_ops;
         return mmu_notifier_register(&kvm->mmu_notifier, current->mm);
 }
 
 #else  /* !(CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER) */
 
 static int kvm_init_mmu_notifier(struct kvm *kvm)
 {
         return 0;
 }
 
 #endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */
 
 static struct kvm_memslots *kvm_alloc_memslots(void)
 {
         int i;
         struct kvm_memslots *slots;
 
         slots = kvzalloc(sizeof(struct kvm_memslots), GFP_KERNEL);
         if (!slots)
                 return NULL;
 
         for (i = 0; i < KVM_MEM_SLOTS_NUM; i++)
                 slots->id_to_index[i] = slots->memslots[i].id = i;
 
         return slots;
 }
 
 static void kvm_destroy_dirty_bitmap(struct kvm_memory_slot *memslot)
 {
         if (!memslot->dirty_bitmap)
                 return;
 
         kvfree(memslot->dirty_bitmap);
         memslot->dirty_bitmap = NULL;
 }
 
 /*
  * Free any memory in @free but not in @dont.
  */
 static void kvm_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free,
                               struct kvm_memory_slot *dont)
 {
         if (!dont || free->dirty_bitmap != dont->dirty_bitmap)
                 kvm_destroy_dirty_bitmap(free);
 
         kvm_arch_free_memslot(kvm, free, dont);
 
         free->npages = 0;
 }
 
 static void kvm_free_memslots(struct kvm *kvm, struct kvm_memslots *slots)
 {
         struct kvm_memory_slot *memslot;
 
         if (!slots)
                 return;
 
         kvm_for_each_memslot(memslot, slots)
                 kvm_free_memslot(kvm, memslot, NULL);
 
         kvfree(slots);
 }
 
 static void kvm_destroy_vm_debugfs(struct kvm *kvm)
 {
         int i;
 
         if (!kvm->debugfs_dentry)
                 return;
 
         debugfs_remove_recursive(kvm->debugfs_dentry);
 
         if (kvm->debugfs_stat_data) {
                 for (i = 0; i < kvm_debugfs_num_entries; i++)
                         kfree(kvm->debugfs_stat_data[i]);
                 kfree(kvm->debugfs_stat_data);
         }
 }
 
 static int kvm_create_vm_debugfs(struct kvm *kvm, int fd)
 {
         char dir_name[ITOA_MAX_LEN * 2];
         struct kvm_stat_data *stat_data;
         struct kvm_stats_debugfs_item *p;
 
         if (!debugfs_initialized())
                 return 0;
 
         snprintf(dir_name, sizeof(dir_name), "%d-%d", task_pid_nr(current), fd);
         kvm->debugfs_dentry = debugfs_create_dir(dir_name, kvm_debugfs_dir);
 
         kvm->debugfs_stat_data = kcalloc(kvm_debugfs_num_entries,
                                          sizeof(*kvm->debugfs_stat_data),
                                          GFP_KERNEL);
         if (!kvm->debugfs_stat_data)
                 return -ENOMEM;
 
         for (p = debugfs_entries; p->name; p++) {
                 stat_data = kzalloc(sizeof(*stat_data), GFP_KERNEL);
                 if (!stat_data)
                         return -ENOMEM;
 
                 stat_data->kvm = kvm;
                 stat_data->offset = p->offset;
                 kvm->debugfs_stat_data[p - debugfs_entries] = stat_data;
                 debugfs_create_file(p->name, 0644, kvm->debugfs_dentry,
                                     stat_data, stat_fops_per_vm[p->kind]);
         }
         return 0;
 }
 
 static struct kvm *kvm_create_vm(unsigned long type)
 {
         int r, i;
         struct kvm *kvm = kvm_arch_alloc_vm();
 
         if (!kvm)
                 return ERR_PTR(-ENOMEM);
 
         spin_lock_init(&kvm->mmu_lock);
         mmgrab(current->mm);
         kvm->mm = current->mm;
         kvm_eventfd_init(kvm);
         mutex_init(&kvm->lock);
         mutex_init(&kvm->irq_lock);
         mutex_init(&kvm->slots_lock);
         refcount_set(&kvm->users_count, 1);
         INIT_LIST_HEAD(&kvm->devices);
 
         r = kvm_arch_init_vm(kvm, type);
         if (r)
                 goto out_err_no_disable;
 
         r = hardware_enable_all();
         if (r)
                 goto out_err_no_disable;
 
 #ifdef CONFIG_HAVE_KVM_IRQFD
         INIT_HLIST_HEAD(&kvm->irq_ack_notifier_list);
 #endif
 
         BUILD_BUG_ON(KVM_MEM_SLOTS_NUM > SHRT_MAX);
 
         r = -ENOMEM;
         for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
                 struct kvm_memslots *slots = kvm_alloc_memslots();
                 if (!slots)
                         goto out_err_no_srcu;
                 /*
                  * Generations must be different for each address space.
                  * Init kvm generation close to the maximum to easily test the
                  * code of handling generation number wrap-around.
                  */
                 slots->generation = i * 2 - 150;
                 rcu_assign_pointer(kvm->memslots[i], slots);
         }
 
         if (init_srcu_struct(&kvm->srcu))
                 goto out_err_no_srcu;
         if (init_srcu_struct(&kvm->irq_srcu))
                 goto out_err_no_irq_srcu;
         for (i = 0; i < KVM_NR_BUSES; i++) {
                 rcu_assign_pointer(kvm->buses[i],
                         kzalloc(sizeof(struct kvm_io_bus), GFP_KERNEL));
                 if (!kvm->buses[i])
                         goto out_err;
         }
 
         r = kvm_init_mmu_notifier(kvm);
         if (r)
                 goto out_err;
 
         spin_lock(&kvm_lock);
         list_add(&kvm->vm_list, &vm_list);
         spin_unlock(&kvm_lock);
 
         preempt_notifier_inc();
 
         return kvm;
 
 out_err:
         cleanup_srcu_struct(&kvm->irq_srcu);
 out_err_no_irq_srcu:
         cleanup_srcu_struct(&kvm->srcu);
 out_err_no_srcu:
         hardware_disable_all();
 out_err_no_disable:
         refcount_set(&kvm->users_count, 0);
         for (i = 0; i < KVM_NR_BUSES; i++)
                 kfree(kvm_get_bus(kvm, i));
         for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++)
                 kvm_free_memslots(kvm, __kvm_memslots(kvm, i));
         kvm_arch_free_vm(kvm);
         mmdrop(current->mm);
         return ERR_PTR(r);
 }
 
 static void kvm_destroy_devices(struct kvm *kvm)
 {
         struct kvm_device *dev, *tmp;
 
         /*
          * We do not need to take the kvm->lock here, because nobody else
          * has a reference to the struct kvm at this point and therefore
          * cannot access the devices list anyhow.
          */
         list_for_each_entry_safe(dev, tmp, &kvm->devices, vm_node) {
                 list_del(&dev->vm_node);
                 dev->ops->destroy(dev);
         }
 }
 
 static void kvm_destroy_vm(struct kvm *kvm)
 {
         int i;
         struct mm_struct *mm = kvm->mm;
 
         kvm_uevent_notify_change(KVM_EVENT_DESTROY_VM, kvm);
         kvm_destroy_vm_debugfs(kvm);
         kvm_arch_sync_events(kvm);
         spin_lock(&kvm_lock);
         list_del(&kvm->vm_list);
         spin_unlock(&kvm_lock);
         kvm_free_irq_routing(kvm);
         for (i = 0; i < KVM_NR_BUSES; i++) {
                 struct kvm_io_bus *bus = kvm_get_bus(kvm, i);
 
                 if (bus)
                         kvm_io_bus_destroy(bus);
                 kvm->buses[i] = NULL;
         }
         kvm_coalesced_mmio_free(kvm);
 #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
         mmu_notifier_unregister(&kvm->mmu_notifier, kvm->mm);
 #else
         kvm_arch_flush_shadow_all(kvm);
 #endif
         kvm_arch_destroy_vm(kvm);
         kvm_destroy_devices(kvm);
         for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++)
                 kvm_free_memslots(kvm, __kvm_memslots(kvm, i));
         cleanup_srcu_struct(&kvm->irq_srcu);
         cleanup_srcu_struct(&kvm->srcu);
         kvm_arch_free_vm(kvm);
         preempt_notifier_dec();
         hardware_disable_all();
         mmdrop(mm);
 }
 
 void kvm_get_kvm(struct kvm *kvm)
 {
         refcount_inc(&kvm->users_count);
 }
 EXPORT_SYMBOL_GPL(kvm_get_kvm);
 
 void kvm_put_kvm(struct kvm *kvm)
 {
         if (refcount_dec_and_test(&kvm->users_count))
                 kvm_destroy_vm(kvm);
 }
 EXPORT_SYMBOL_GPL(kvm_put_kvm);
 
 
 static int kvm_vm_release(struct inode *inode, struct file *filp)
 {
         struct kvm *kvm = filp->private_data;
 
         kvm_irqfd_release(kvm);
 
         kvm_put_kvm(kvm);
         return 0;
 }
 
 /*
  * Allocation size is twice as large as the actual dirty bitmap size.
  * See x86's kvm_vm_ioctl_get_dirty_log() why this is needed.
  */
 static int kvm_create_dirty_bitmap(struct kvm_memory_slot *memslot)
 {
         unsigned long dirty_bytes = 2 * kvm_dirty_bitmap_bytes(memslot);
 
         memslot->dirty_bitmap = kvzalloc(dirty_bytes, GFP_KERNEL);
         if (!memslot->dirty_bitmap)
                 return -ENOMEM;
 
         return 0;
 }
 
 /*
  * Insert memslot and re-sort memslots based on their GFN,
  * so binary search could be used to lookup GFN.
  * Sorting algorithm takes advantage of having initially
  * sorted array and known changed memslot position.
  */
 static void update_memslots(struct kvm_memslots *slots,
                             struct kvm_memory_slot *new,
                             enum kvm_mr_change change)
 {
         int id = new->id;
         int i = slots->id_to_index[id];
         struct kvm_memory_slot *mslots = slots->memslots;
 
         WARN_ON(mslots[i].id != id);
         switch (change) {
         case KVM_MR_CREATE:
                 slots->used_slots++;
                 WARN_ON(mslots[i].npages || !new->npages);
                 break;
         case KVM_MR_DELETE:
                 slots->used_slots--;
                 WARN_ON(new->npages || !mslots[i].npages);
                 break;
         default:
                 break;
         }
 
         while (i < KVM_MEM_SLOTS_NUM - 1 &&
                new->base_gfn <= mslots[i + 1].base_gfn) {
                 if (!mslots[i + 1].npages)
                         break;
                 mslots[i] = mslots[i + 1];
                 slots->id_to_index[mslots[i].id] = i;
                 i++;
         }
 
         /*
          * The ">=" is needed when creating a slot with base_gfn == 0,
          * so that it moves before all those with base_gfn == npages == 0.
          *
          * On the other hand, if new->npages is zero, the above loop has
          * already left i pointing to the beginning of the empty part of
          * mslots, and the ">=" would move the hole backwards in this
          * case---which is wrong.  So skip the loop when deleting a slot.
          */
         if (new->npages) {
                 while (i > 0 &&
                        new->base_gfn >= mslots[i - 1].base_gfn) {
                         mslots[i] = mslots[i - 1];
                         slots->id_to_index[mslots[i].id] = i;
                         i--;
                 }
         } else
                 WARN_ON_ONCE(i != slots->used_slots);
 
         mslots[i] = *new;
         slots->id_to_index[mslots[i].id] = i;
 }
 
 static int check_memory_region_flags(const struct kvm_userspace_memory_region *mem)
 {
         u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES;
 
 #ifdef __KVM_HAVE_READONLY_MEM
         valid_flags |= KVM_MEM_READONLY;
 #endif
 
         if (mem->flags & ~valid_flags)
                 return -EINVAL;
 
         return 0;
 }
 
 static struct kvm_memslots *install_new_memslots(struct kvm *kvm,
                 int as_id, struct kvm_memslots *slots)
 {
         struct kvm_memslots *old_memslots = __kvm_memslots(kvm, as_id);
         u64 gen;
 
         /*
          * Set the low bit in the generation, which disables SPTE caching
          * until the end of synchronize_srcu_expedited.
          */
         WARN_ON(old_memslots->generation & 1);
         slots->generation = old_memslots->generation + 1;
 
         rcu_assign_pointer(kvm->memslots[as_id], slots);
         synchronize_srcu_expedited(&kvm->srcu);
 
         /*
          * Increment the new memslot generation a second time. This prevents
          * vm exits that race with memslot updates from caching a memslot
          * generation that will (potentially) be valid forever.
          *
          * Generations must be unique even across address spaces.  We do not need
          * a global counter for that, instead the generation space is evenly split
          * across address spaces.  For example, with two address spaces, address
          * space 0 will use generations 0, 4, 8, ... while * address space 1 will
          * use generations 2, 6, 10, 14, ...
          */
         gen = slots->generation + KVM_ADDRESS_SPACE_NUM * 2 - 1;
 
         kvm_arch_memslots_updated(kvm, gen);
 
         slots->generation = gen;
 
         return old_memslots;
 }
 
 /*
  * Allocate some memory and give it an address in the guest physical address
  * space.
  *
  * Discontiguous memory is allowed, mostly for framebuffers.
  *
  * Must be called holding kvm->slots_lock for write.
  */
 int __kvm_set_memory_region(struct kvm *kvm,
                             const struct kvm_userspace_memory_region *mem)
 {
         int r;
         gfn_t base_gfn;
         unsigned long npages;
         struct kvm_memory_slot *slot;
         struct kvm_memory_slot old, new;
         struct kvm_memslots *slots = NULL, *old_memslots;
         int as_id, id;
         enum kvm_mr_change change;
 
         r = check_memory_region_flags(mem);
         if (r)
                 goto out;
 
         r = -EINVAL;
         as_id = mem->slot >> 16;
         id = (u16)mem->slot;
 
         /* General sanity checks */
         if (mem->memory_size & (PAGE_SIZE - 1))
                 goto out;
         if (mem->guest_phys_addr & (PAGE_SIZE - 1))
                 goto out;
         /* We can read the guest memory with __xxx_user() later on. */
         if ((id < KVM_USER_MEM_SLOTS) &&
             ((mem->userspace_addr & (PAGE_SIZE - 1)) ||
              !access_ok((void __user *)(unsigned long)mem->userspace_addr,
                         mem->memory_size)))
                 goto out;
         if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_MEM_SLOTS_NUM)
                 goto out;
         if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr)
                 goto out;
 
         slot = id_to_memslot(__kvm_memslots(kvm, as_id), id);
         base_gfn = mem->guest_phys_addr >> PAGE_SHIFT;
         npages = mem->memory_size >> PAGE_SHIFT;
 
         if (npages > KVM_MEM_MAX_NR_PAGES)
                 goto out;
 
         new = old = *slot;
 
         new.id = id;
         new.base_gfn = base_gfn;
         new.npages = npages;
         new.flags = mem->flags;
 
         if (npages) {
                 if (!old.npages)
                         change = KVM_MR_CREATE;
                 else { /* Modify an existing slot. */
                         if ((mem->userspace_addr != old.userspace_addr) ||
                             (npages != old.npages) ||
                             ((new.flags ^ old.flags) & KVM_MEM_READONLY))
                                 goto out;
 
                         if (base_gfn != old.base_gfn)
                                 change = KVM_MR_MOVE;
                         else if (new.flags != old.flags)
                                 change = KVM_MR_FLAGS_ONLY;
                         else { /* Nothing to change. */
                                 r = 0;
                                 goto out;
                         }
                 }
         } else {
                 if (!old.npages)
                         goto out;
 
                 change = KVM_MR_DELETE;
                 new.base_gfn = 0;
                 new.flags = 0;
         }
 
         if ((change == KVM_MR_CREATE) || (change == KVM_MR_MOVE)) {
                 /* Check for overlaps */
                 r = -EEXIST;
                 kvm_for_each_memslot(slot, __kvm_memslots(kvm, as_id)) {
                         if (slot->id == id)
                                 continue;
                         if (!((base_gfn + npages <= slot->base_gfn) ||
                               (base_gfn >= slot->base_gfn + slot->npages)))
                                 goto out;
                 }
         }
 
         /* Free page dirty bitmap if unneeded */
         if (!(new.flags & KVM_MEM_LOG_DIRTY_PAGES))
                 new.dirty_bitmap = NULL;
 
         r = -ENOMEM;
         if (change == KVM_MR_CREATE) {
                 new.userspace_addr = mem->userspace_addr;
 
                 if (kvm_arch_create_memslot(kvm, &new, npages))
                         goto out_free;
         }
 
         /* Allocate page dirty bitmap if needed */
         if ((new.flags & KVM_MEM_LOG_DIRTY_PAGES) && !new.dirty_bitmap) {
                 if (kvm_create_dirty_bitmap(&new) < 0)
                         goto out_free;
         }
 
         slots = kvzalloc(sizeof(struct kvm_memslots), GFP_KERNEL);
         if (!slots)
                 goto out_free;
         memcpy(slots, __kvm_memslots(kvm, as_id), sizeof(struct kvm_memslots));
 
         if ((change == KVM_MR_DELETE) || (change == KVM_MR_MOVE)) {
                 slot = id_to_memslot(slots, id);
                 slot->flags |= KVM_MEMSLOT_INVALID;
 
                 old_memslots = install_new_memslots(kvm, as_id, slots);
 
                 /* From this point no new shadow pages pointing to a deleted,
                  * or moved, memslot will be created.
                  *
                  * validation of sp->gfn happens in:
                  *      - gfn_to_hva (kvm_read_guest, gfn_to_pfn)
                  *      - kvm_is_visible_gfn (mmu_check_roots)
                  */
                 kvm_arch_flush_shadow_memslot(kvm, slot);
 
                 /*
                  * We can re-use the old_memslots from above, the only difference
                  * from the currently installed memslots is the invalid flag.  This
                  * will get overwritten by update_memslots anyway.
                  */
                 slots = old_memslots;
         }
 
         r = kvm_arch_prepare_memory_region(kvm, &new, mem, change);
         if (r)
                 goto out_slots;
 
         /* actual memory is freed via old in kvm_free_memslot below */
         if (change == KVM_MR_DELETE) {
                 new.dirty_bitmap = NULL;
                 memset(&new.arch, 0, sizeof(new.arch));
         }
 
         update_memslots(slots, &new, change);
         old_memslots = install_new_memslots(kvm, as_id, slots);
 
         kvm_arch_commit_memory_region(kvm, mem, &old, &new, change);
 
         kvm_free_memslot(kvm, &old, &new);
         kvfree(old_memslots);
         return 0;
 
 out_slots:
         kvfree(slots);
 out_free:
         kvm_free_memslot(kvm, &new, &old);
 out:
         return r;
 }
 EXPORT_SYMBOL_GPL(__kvm_set_memory_region);
 
 int kvm_set_memory_region(struct kvm *kvm,
                           const struct kvm_userspace_memory_region *mem)
 {
         int r;
 
         mutex_lock(&kvm->slots_lock);
         r = __kvm_set_memory_region(kvm, mem);
         mutex_unlock(&kvm->slots_lock);
         return r;
 }
 EXPORT_SYMBOL_GPL(kvm_set_memory_region);
 
 static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
                                           struct kvm_userspace_memory_region *mem)
 {
         if ((u16)mem->slot >= KVM_USER_MEM_SLOTS)
                 return -EINVAL;
 
         return kvm_set_memory_region(kvm, mem);
 }
 
 int kvm_get_dirty_log(struct kvm *kvm,
                         struct kvm_dirty_log *log, int *is_dirty)
 {
         struct kvm_memslots *slots;
         struct kvm_memory_slot *memslot;
         int i, as_id, id;
         unsigned long n;
         unsigned long any = 0;
 
         as_id = log->slot >> 16;
         id = (u16)log->slot;
         if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS)
                 return -EINVAL;
 
         slots = __kvm_memslots(kvm, as_id);
         memslot = id_to_memslot(slots, id);
         if (!memslot->dirty_bitmap)
                 return -ENOENT;
 
         n = kvm_dirty_bitmap_bytes(memslot);
 
         for (i = 0; !any && i < n/sizeof(long); ++i)
                 any = memslot->dirty_bitmap[i];
 
         if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n))
                 return -EFAULT;
 
         if (any)
                 *is_dirty = 1;
         return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_get_dirty_log);
 
 #ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
 /**
  * kvm_get_dirty_log_protect - get a snapshot of dirty pages, and if any pages
  *      and reenable dirty page tracking for the corresponding pages.
  * @kvm:        pointer to kvm instance
  * @log:        slot id and address to which we copy the log
  * @is_dirty:   flag set if any page is dirty
  *
  * We need to keep it in mind that VCPU threads can write to the bitmap
  * concurrently. So, to avoid losing track of dirty pages we keep the
  * following order:
  *
  *    1. Take a snapshot of the bit and clear it if needed.
  *    2. Write protect the corresponding page.
  *    3. Copy the snapshot to the userspace.
  *    4. Upon return caller flushes TLB's if needed.
  *
  * Between 2 and 4, the guest may write to the page using the remaining TLB
  * entry.  This is not a problem because the page is reported dirty using
  * the snapshot taken before and step 4 ensures that writes done after
  * exiting to userspace will be logged for the next call.
  *
  */
 int kvm_get_dirty_log_protect(struct kvm *kvm,
                         struct kvm_dirty_log *log, bool *flush)
 {
         struct kvm_memslots *slots;
         struct kvm_memory_slot *memslot;
         int i, as_id, id;
         unsigned long n;
         unsigned long *dirty_bitmap;
         unsigned long *dirty_bitmap_buffer;
 
         as_id = log->slot >> 16;
         id = (u16)log->slot;
         if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS)
                 return -EINVAL;
 
         slots = __kvm_memslots(kvm, as_id);
         memslot = id_to_memslot(slots, id);
 
         dirty_bitmap = memslot->dirty_bitmap;
         if (!dirty_bitmap)
                 return -ENOENT;
 
         n = kvm_dirty_bitmap_bytes(memslot);
         *flush = false;
         if (kvm->manual_dirty_log_protect) {
                 /*
                  * Unlike kvm_get_dirty_log, we always return false in *flush,
                  * because no flush is needed until KVM_CLEAR_DIRTY_LOG.  There
                  * is some code duplication between this function and
                  * kvm_get_dirty_log, but hopefully all architecture
                  * transition to kvm_get_dirty_log_protect and kvm_get_dirty_log
                  * can be eliminated.
                  */
                 dirty_bitmap_buffer = dirty_bitmap;
         } else {
                 dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot);
                 memset(dirty_bitmap_buffer, 0, n);
 
                 spin_lock(&kvm->mmu_lock);
                 for (i = 0; i < n / sizeof(long); i++) {
                         unsigned long mask;
                         gfn_t offset;
 
                         if (!dirty_bitmap[i])
                                 continue;
 
                         *flush = true;
                         mask = xchg(&dirty_bitmap[i], 0);
                         dirty_bitmap_buffer[i] = mask;
 
                         if (mask) {
                                 offset = i * BITS_PER_LONG;
                                 kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot,
                                                                         offset, mask);
                         }
                 }
                 spin_unlock(&kvm->mmu_lock);
         }
 
         if (copy_to_user(log->dirty_bitmap, dirty_bitmap_buffer, n))
                 return -EFAULT;
         return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_get_dirty_log_protect);
 
 /**
  * kvm_clear_dirty_log_protect - clear dirty bits in the bitmap
  *      and reenable dirty page tracking for the corresponding pages.
  * @kvm:        pointer to kvm instance
  * @log:        slot id and address from which to fetch the bitmap of dirty pages
  */
 int kvm_clear_dirty_log_protect(struct kvm *kvm,
                                 struct kvm_clear_dirty_log *log, bool *flush)
 {
         struct kvm_memslots *slots;
         struct kvm_memory_slot *memslot;
         int as_id, id;
         gfn_t offset;
         unsigned long i, n;
         unsigned long *dirty_bitmap;
         unsigned long *dirty_bitmap_buffer;
 
         as_id = log->slot >> 16;
         id = (u16)log->slot;
         if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS)
                 return -EINVAL;
 
         if (log->first_page & 63)
                 return -EINVAL;
 
         slots = __kvm_memslots(kvm, as_id);
         memslot = id_to_memslot(slots, id);
 
         dirty_bitmap = memslot->dirty_bitmap;
         if (!dirty_bitmap)
                 return -ENOENT;
 
         n = ALIGN(log->num_pages, BITS_PER_LONG) / 8;
 
         if (log->first_page > memslot->npages ||
             log->num_pages > memslot->npages - log->first_page ||
             (log->num_pages < memslot->npages - log->first_page && (log->num_pages & 63)))
             return -EINVAL;
 
         *flush = false;
         dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot);
         if (copy_from_user(dirty_bitmap_buffer, log->dirty_bitmap, n))
                 return -EFAULT;
 
         spin_lock(&kvm->mmu_lock);
         for (offset = log->first_page,
              i = offset / BITS_PER_LONG, n = log->num_pages / BITS_PER_LONG; n--;
              i++, offset += BITS_PER_LONG) {
                 unsigned long mask = *dirty_bitmap_buffer++;
                 atomic_long_t *p = (atomic_long_t *) &dirty_bitmap[i];
                 if (!mask)
                         continue;
 
                 mask &= atomic_long_fetch_andnot(mask, p);
 
                 /*
                  * mask contains the bits that really have been cleared.  This
                  * never includes any bits beyond the length of the memslot (if
                  * the length is not aligned to 64 pages), therefore it is not
                  * a problem if userspace sets them in log->dirty_bitmap.
                 */
                 if (mask) {
                         *flush = true;
                         kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot,
                                                                 offset, mask);
                 }
         }
         spin_unlock(&kvm->mmu_lock);
 
         return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_clear_dirty_log_protect);
 #endif
 
 bool kvm_largepages_enabled(void)
 {
         return largepages_enabled;
 }
 
 void kvm_disable_largepages(void)
 {
         largepages_enabled = false;
 }
 EXPORT_SYMBOL_GPL(kvm_disable_largepages);
 
 struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
 {
         return __gfn_to_memslot(kvm_memslots(kvm), gfn);
 }
 EXPORT_SYMBOL_GPL(gfn_to_memslot);
 
 struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn)
 {
         return __gfn_to_memslot(kvm_vcpu_memslots(vcpu), gfn);
 }
 
 bool kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
 {
         struct kvm_memory_slot *memslot = gfn_to_memslot(kvm, gfn);
 
         if (!memslot || memslot->id >= KVM_USER_MEM_SLOTS ||
               memslot->flags & KVM_MEMSLOT_INVALID)
                 return false;
 
         return true;
 }
 EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);
 
 unsigned long kvm_host_page_size(struct kvm *kvm, gfn_t gfn)
 {
         struct vm_area_struct *vma;
         unsigned long addr, size;
 
         size = PAGE_SIZE;
 
         addr = gfn_to_hva(kvm, gfn);
         if (kvm_is_error_hva(addr))
                 return PAGE_SIZE;
 
         down_read(&current->mm->mmap_sem);
         vma = find_vma(current->mm, addr);
         if (!vma)
                 goto out;
 
         size = vma_kernel_pagesize(vma);
 
 out:
         up_read(&current->mm->mmap_sem);
 
         return size;
 }
 
 static bool memslot_is_readonly(struct kvm_memory_slot *slot)
 {
         return slot->flags & KVM_MEM_READONLY;
 }
 
 static unsigned long __gfn_to_hva_many(struct kvm_memory_slot *slot, gfn_t gfn,
                                        gfn_t *nr_pages, bool write)
 {
         if (!slot || slot->flags & KVM_MEMSLOT_INVALID)
                 return KVM_HVA_ERR_BAD;
 
         if (memslot_is_readonly(slot) && write)
                 return KVM_HVA_ERR_RO_BAD;
 
         if (nr_pages)
                 *nr_pages = slot->npages - (gfn - slot->base_gfn);
 
         return __gfn_to_hva_memslot(slot, gfn);
 }
 
 static unsigned long gfn_to_hva_many(struct kvm_memory_slot *slot, gfn_t gfn,
                                      gfn_t *nr_pages)
 {
         return __gfn_to_hva_many(slot, gfn, nr_pages, true);
 }
 
 unsigned long gfn_to_hva_memslot(struct kvm_memory_slot *slot,
                                         gfn_t gfn)
 {
         return gfn_to_hva_many(slot, gfn, NULL);
 }
 EXPORT_SYMBOL_GPL(gfn_to_hva_memslot);
 
 unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
 {
         return gfn_to_hva_many(gfn_to_memslot(kvm, gfn), gfn, NULL);
 }
 EXPORT_SYMBOL_GPL(gfn_to_hva);
 
 unsigned long kvm_vcpu_gfn_to_hva(struct kvm_vcpu *vcpu, gfn_t gfn)
 {
         return gfn_to_hva_many(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn, NULL);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_hva);
 
 /*
  * Return the hva of a @gfn and the R/W attribute if possible.
  *
  * @slot: the kvm_memory_slot which contains @gfn
  * @gfn: the gfn to be translated
  * @writable: used to return the read/write attribute of the @slot if the hva
  * is valid and @writable is not NULL
  */
 unsigned long gfn_to_hva_memslot_prot(struct kvm_memory_slot *slot,
                                       gfn_t gfn, bool *writable)
 {
         unsigned long hva = __gfn_to_hva_many(slot, gfn, NULL, false);
 
         if (!kvm_is_error_hva(hva) && writable)
                 *writable = !memslot_is_readonly(slot);
 
         return hva;
 }
 
 unsigned long gfn_to_hva_prot(struct kvm *kvm, gfn_t gfn, bool *writable)
 {
         struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
 
         return gfn_to_hva_memslot_prot(slot, gfn, writable);
 }
 
 unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *writable)
 {
         struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
 
         return gfn_to_hva_memslot_prot(slot, gfn, writable);
 }
 
 static inline int check_user_page_hwpoison(unsigned long addr)
 {
         int rc, flags = FOLL_HWPOISON | FOLL_WRITE;
 
         rc = get_user_pages(addr, 1, flags, NULL, NULL);
         return rc == -EHWPOISON;
 }
 
 /*
  * The fast path to get the writable pfn which will be stored in @pfn,
  * true indicates success, otherwise false is returned.  It's also the
  * only part that runs if we can are in atomic context.
  */
 static bool hva_to_pfn_fast(unsigned long addr, bool write_fault,
                             bool *writable, kvm_pfn_t *pfn)
 {
         struct page *page[1];
         int npages;
 
         /*
          * Fast pin a writable pfn only if it is a write fault request
          * or the caller allows to map a writable pfn for a read fault
          * request.
          */
         if (!(write_fault || writable))
                 return false;
 
         npages = __get_user_pages_fast(addr, 1, 1, page);
         if (npages == 1) {
                 *pfn = page_to_pfn(page[0]);
 
                 if (writable)
                         *writable = true;
                 return true;
         }
 
         return false;
 }
 
 /*
  * The slow path to get the pfn of the specified host virtual address,
  * 1 indicates success, -errno is returned if error is detected.
  */
 static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault,
                            bool *writable, kvm_pfn_t *pfn)
 {
         unsigned int flags = FOLL_HWPOISON;
         struct page *page;
         int npages = 0;
 
         might_sleep();
 
         if (writable)
                 *writable = write_fault;
 
         if (write_fault)
                 flags |= FOLL_WRITE;
         if (async)
                 flags |= FOLL_NOWAIT;
 
         npages = get_user_pages_unlocked(addr, 1, &page, flags);
         if (npages != 1)
                 return npages;
 
         /* map read fault as writable if possible */
         if (unlikely(!write_fault) && writable) {
                 struct page *wpage;
 
                 if (__get_user_pages_fast(addr, 1, 1, &wpage) == 1) {
                         *writable = true;
                         put_page(page);
                         page = wpage;
                 }
         }
         *pfn = page_to_pfn(page);
         return npages;
 }
 
 static bool vma_is_valid(struct vm_area_struct *vma, bool write_fault)
 {
         if (unlikely(!(vma->vm_flags & VM_READ)))
                 return false;
 
         if (write_fault && (unlikely(!(vma->vm_flags & VM_WRITE))))
                 return false;
 
         return true;
 }
 
 static int hva_to_pfn_remapped(struct vm_area_struct *vma,
                                unsigned long addr, bool *async,
                                bool write_fault, bool *writable,
                                kvm_pfn_t *p_pfn)
 {
         unsigned long pfn;
         int r;
 
         r = follow_pfn(vma, addr, &pfn);
         if (r) {
                 /*
                  * get_user_pages fails for VM_IO and VM_PFNMAP vmas and does
                  * not call the fault handler, so do it here.
                  */
                 bool unlocked = false;
                 r = fixup_user_fault(current, current->mm, addr,
                                      (write_fault ? FAULT_FLAG_WRITE : 0),
                                      &unlocked);
                 if (unlocked)
                         return -EAGAIN;
                 if (r)
                         return r;
 
                 r = follow_pfn(vma, addr, &pfn);
                 if (r)
                         return r;
 
         }
 
         if (writable)
                 *writable = true;
 
         /*
          * Get a reference here because callers of *hva_to_pfn* and
          * *gfn_to_pfn* ultimately call kvm_release_pfn_clean on the
          * returned pfn.  This is only needed if the VMA has VM_MIXEDMAP
          * set, but the kvm_get_pfn/kvm_release_pfn_clean pair will
          * simply do nothing for reserved pfns.
          *
          * Whoever called remap_pfn_range is also going to call e.g.
          * unmap_mapping_range before the underlying pages are freed,
          * causing a call to our MMU notifier.
          */ 
         kvm_get_pfn(pfn);
 
         *p_pfn = pfn;
         return 0;
 }
 
 /*
  * Pin guest page in memory and return its pfn.
  * @addr: host virtual address which maps memory to the guest
  * @atomic: whether this function can sleep
  * @async: whether this function need to wait IO complete if the
  *         host page is not in the memory
  * @write_fault: whether we should get a writable host page
  * @writable: whether it allows to map a writable host page for !@write_fault
  *
  * The function will map a writable host page for these two cases:
  * 1): @write_fault = true
  * 2): @write_fault = false && @writable, @writable will tell the caller
  *     whether the mapping is writable.
  */
 static kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
                         bool write_fault, bool *writable)
 {
         struct vm_area_struct *vma;
         kvm_pfn_t pfn = 0;
         int npages, r;
 
         /* we can do it either atomically or asynchronously, not both */
         BUG_ON(atomic && async);
 
         if (hva_to_pfn_fast(addr, write_fault, writable, &pfn))
                 return pfn;
 
         if (atomic)
                 return KVM_PFN_ERR_FAULT;
 
         npages = hva_to_pfn_slow(addr, async, write_fault, writable, &pfn);
         if (npages == 1)
                 return pfn;
 
         down_read(&current->mm->mmap_sem);
         if (npages == -EHWPOISON ||
               (!async && check_user_page_hwpoison(addr))) {
                 pfn = KVM_PFN_ERR_HWPOISON;
                 goto exit;
         }
 
 retry:
         vma = find_vma_intersection(current->mm, addr, addr + 1);
 
         if (vma == NULL)
                 pfn = KVM_PFN_ERR_FAULT;
         else if (vma->vm_flags & (VM_IO | VM_PFNMAP)) {
                 r = hva_to_pfn_remapped(vma, addr, async, write_fault, writable, &pfn);
                 if (r == -EAGAIN)
                         goto retry;
                 if (r < 0)
                         pfn = KVM_PFN_ERR_FAULT;
         } else {
                 if (async && vma_is_valid(vma, write_fault))
                         *async = true;
                 pfn = KVM_PFN_ERR_FAULT;
         }
 exit:
         up_read(&current->mm->mmap_sem);
         return pfn;
 }
 
 kvm_pfn_t __gfn_to_pfn_memslot(struct kvm_memory_slot *slot, gfn_t gfn,
                                bool atomic, bool *async, bool write_fault,
                                bool *writable)
 {
         unsigned long addr = __gfn_to_hva_many(slot, gfn, NULL, write_fault);
 
         if (addr == KVM_HVA_ERR_RO_BAD) {
                 if (writable)
                         *writable = false;
                 return KVM_PFN_ERR_RO_FAULT;
         }
 
         if (kvm_is_error_hva(addr)) {
                 if (writable)
                         *writable = false;
                 return KVM_PFN_NOSLOT;
         }
 
         /* Do not map writable pfn in the readonly memslot. */
         if (writable && memslot_is_readonly(slot)) {
                 *writable = false;
                 writable = NULL;
         }
 
         return hva_to_pfn(addr, atomic, async, write_fault,
                           writable);
 }
 EXPORT_SYMBOL_GPL(__gfn_to_pfn_memslot);
 
 kvm_pfn_t gfn_to_pfn_prot(struct kvm *kvm, gfn_t gfn, bool write_fault,
                       bool *writable)
 {
         return __gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn, false, NULL,
                                     write_fault, writable);
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn_prot);
 
 kvm_pfn_t gfn_to_pfn_memslot(struct kvm_memory_slot *slot, gfn_t gfn)
 {
         return __gfn_to_pfn_memslot(slot, gfn, false, NULL, true, NULL);
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot);
 
 kvm_pfn_t gfn_to_pfn_memslot_atomic(struct kvm_memory_slot *slot, gfn_t gfn)
 {
         return __gfn_to_pfn_memslot(slot, gfn, true, NULL, true, NULL);
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot_atomic);
 
 kvm_pfn_t gfn_to_pfn_atomic(struct kvm *kvm, gfn_t gfn)
 {
         return gfn_to_pfn_memslot_atomic(gfn_to_memslot(kvm, gfn), gfn);
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn_atomic);
 
 kvm_pfn_t kvm_vcpu_gfn_to_pfn_atomic(struct kvm_vcpu *vcpu, gfn_t gfn)
 {
         return gfn_to_pfn_memslot_atomic(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_pfn_atomic);
 
 kvm_pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
 {
         return gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn);
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn);
 
 kvm_pfn_t kvm_vcpu_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn)
 {
         return gfn_to_pfn_memslot(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_pfn);
 
 int gfn_to_page_many_atomic(struct kvm_memory_slot *slot, gfn_t gfn,
                             struct page **pages, int nr_pages)
 {
         unsigned long addr;
         gfn_t entry = 0;
 
         addr = gfn_to_hva_many(slot, gfn, &entry);
         if (kvm_is_error_hva(addr))
                 return -1;
 
         if (entry < nr_pages)
                 return 0;
 
         return __get_user_pages_fast(addr, nr_pages, 1, pages);
 }
 EXPORT_SYMBOL_GPL(gfn_to_page_many_atomic);
 
 static struct page *kvm_pfn_to_page(kvm_pfn_t pfn)
 {
         if (is_error_noslot_pfn(pfn))
                 return KVM_ERR_PTR_BAD_PAGE;
 
         if (kvm_is_reserved_pfn(pfn)) {
                 WARN_ON(1);
                 return KVM_ERR_PTR_BAD_PAGE;
         }
 
         return pfn_to_page(pfn);
 }
 
 struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
 {
         kvm_pfn_t pfn;
 
         pfn = gfn_to_pfn(kvm, gfn);
 
         return kvm_pfn_to_page(pfn);
 }
 EXPORT_SYMBOL_GPL(gfn_to_page);
 
 struct page *kvm_vcpu_gfn_to_page(struct kvm_vcpu *vcpu, gfn_t gfn)
 {
         kvm_pfn_t pfn;
 
         pfn = kvm_vcpu_gfn_to_pfn(vcpu, gfn);
 
         return kvm_pfn_to_page(pfn);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_page);
 
 void kvm_release_page_clean(struct page *page)
 {
         WARN_ON(is_error_page(page));
 
         kvm_release_pfn_clean(page_to_pfn(page));
 }
 EXPORT_SYMBOL_GPL(kvm_release_page_clean);
 
 void kvm_release_pfn_clean(kvm_pfn_t pfn)
 {
         if (!is_error_noslot_pfn(pfn) && !kvm_is_reserved_pfn(pfn))
                 put_page(pfn_to_page(pfn));
 }
 EXPORT_SYMBOL_GPL(kvm_release_pfn_clean);
 
 void kvm_release_page_dirty(struct page *page)
 {
         WARN_ON(is_error_page(page));
 
         kvm_release_pfn_dirty(page_to_pfn(page));
 }
 EXPORT_SYMBOL_GPL(kvm_release_page_dirty);
 
 void kvm_release_pfn_dirty(kvm_pfn_t pfn)
 {
         kvm_set_pfn_dirty(pfn);
         kvm_release_pfn_clean(pfn);
 }
 EXPORT_SYMBOL_GPL(kvm_release_pfn_dirty);
 
 void kvm_set_pfn_dirty(kvm_pfn_t pfn)
 {
         if (!kvm_is_reserved_pfn(pfn)) {
                 struct page *page = pfn_to_page(pfn);
 
                 if (!PageReserved(page))
                         SetPageDirty(page);
         }
 }
 EXPORT_SYMBOL_GPL(kvm_set_pfn_dirty);
 
 void kvm_set_pfn_accessed(kvm_pfn_t pfn)
 {
         if (!kvm_is_reserved_pfn(pfn))
                 mark_page_accessed(pfn_to_page(pfn));
 }
 EXPORT_SYMBOL_GPL(kvm_set_pfn_accessed);
 
 void kvm_get_pfn(kvm_pfn_t pfn)
 {
         if (!kvm_is_reserved_pfn(pfn))
                 get_page(pfn_to_page(pfn));
 }
 EXPORT_SYMBOL_GPL(kvm_get_pfn);
 
 static int next_segment(unsigned long len, int offset)
 {
         if (len > PAGE_SIZE - offset)
                 return PAGE_SIZE - offset;
         else
                 return len;
 }
 
 static int __kvm_read_guest_page(struct kvm_memory_slot *slot, gfn_t gfn,
                                  void *data, int offset, int len)
 {
         int r;
         unsigned long addr;
 
         addr = gfn_to_hva_memslot_prot(slot, gfn, NULL);
         if (kvm_is_error_hva(addr))
                 return -EFAULT;
         r = __copy_from_user(data, (void __user *)addr + offset, len);
         if (r)
                 return -EFAULT;
         return 0;
 }
 
 int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
                         int len)
 {
         struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
 
         return __kvm_read_guest_page(slot, gfn, data, offset, len);
 }
 EXPORT_SYMBOL_GPL(kvm_read_guest_page);
 
 int kvm_vcpu_read_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, void *data,
                              int offset, int len)
 {
         struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
 
         return __kvm_read_guest_page(slot, gfn, data, offset, len);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_page);
 
 int kvm_read_guest(struct kvm *kvm, gpa_t gpa, void *data, unsigned long len)
 {
         gfn_t gfn = gpa >> PAGE_SHIFT;
         int seg;
         int offset = offset_in_page(gpa);
         int ret;
 
         while ((seg = next_segment(len, offset)) != 0) {
                 ret = kvm_read_guest_page(kvm, gfn, data, offset, seg);
                 if (ret < 0)
                         return ret;
                 offset = 0;
                 len -= seg;
                 data += seg;
                 ++gfn;
         }
         return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_read_guest);
 
 int kvm_vcpu_read_guest(struct kvm_vcpu *vcpu, gpa_t gpa, void *data, unsigned long len)
 {
         gfn_t gfn = gpa >> PAGE_SHIFT;
         int seg;
         int offset = offset_in_page(gpa);
         int ret;
 
         while ((seg = next_segment(len, offset)) != 0) {
                 ret = kvm_vcpu_read_guest_page(vcpu, gfn, data, offset, seg);
                 if (ret < 0)
                         return ret;
                 offset = 0;
                 len -= seg;
                 data += seg;
                 ++gfn;
         }
         return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest);
 
 static int __kvm_read_guest_atomic(struct kvm_memory_slot *slot, gfn_t gfn,
                                    void *data, int offset, unsigned long len)
 {
         int r;
         unsigned long addr;
 
         addr = gfn_to_hva_memslot_prot(slot, gfn, NULL);
         if (kvm_is_error_hva(addr))
                 return -EFAULT;
         pagefault_disable();
         r = __copy_from_user_inatomic(data, (void __user *)addr + offset, len);
         pagefault_enable();
         if (r)
                 return -EFAULT;
         return 0;
 }
 
 int kvm_read_guest_atomic(struct kvm *kvm, gpa_t gpa, void *data,
                           unsigned long len)
 {
         gfn_t gfn = gpa >> PAGE_SHIFT;
         struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
         int offset = offset_in_page(gpa);
 
         return __kvm_read_guest_atomic(slot, gfn, data, offset, len);
 }
 EXPORT_SYMBOL_GPL(kvm_read_guest_atomic);
 
 int kvm_vcpu_read_guest_atomic(struct kvm_vcpu *vcpu, gpa_t gpa,
                                void *data, unsigned long len)
 {
         gfn_t gfn = gpa >> PAGE_SHIFT;
         struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
         int offset = offset_in_page(gpa);
 
         return __kvm_read_guest_atomic(slot, gfn, data, offset, len);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_atomic);
 
 static int __kvm_write_guest_page(struct kvm_memory_slot *memslot, gfn_t gfn,
                                   const void *data, int offset, int len)
 {
         int r;
         unsigned long addr;
 
         addr = gfn_to_hva_memslot(memslot, gfn);
         if (kvm_is_error_hva(addr))
                 return -EFAULT;
         r = __copy_to_user((void __user *)addr + offset, data, len);
         if (r)
                 return -EFAULT;
         mark_page_dirty_in_slot(memslot, gfn);
         return 0;
 }
 
 int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn,
                          const void *data, int offset, int len)
 {
         struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
 
         return __kvm_write_guest_page(slot, gfn, data, offset, len);
 }
 EXPORT_SYMBOL_GPL(kvm_write_guest_page);
 
 int kvm_vcpu_write_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn,
                               const void *data, int offset, int len)
 {
         struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
 
         return __kvm_write_guest_page(slot, gfn, data, offset, len);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_write_guest_page);
 
 int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data,
                     unsigned long len)
 {
         gfn_t gfn = gpa >> PAGE_SHIFT;
         int seg;
         int offset = offset_in_page(gpa);
         int ret;
 
         while ((seg = next_segment(len, offset)) != 0) {
                 ret = kvm_write_guest_page(kvm, gfn, data, offset, seg);
                 if (ret < 0)
                         return ret;
                 offset = 0;
                 len -= seg;
                 data += seg;
                 ++gfn;
         }
         return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_write_guest);
 
 int kvm_vcpu_write_guest(struct kvm_vcpu *vcpu, gpa_t gpa, const void *data,
                          unsigned long len)
 {
         gfn_t gfn = gpa >> PAGE_SHIFT;
         int seg;
         int offset = offset_in_page(gpa);
         int ret;
 
         while ((seg = next_segment(len, offset)) != 0) {
                 ret = kvm_vcpu_write_guest_page(vcpu, gfn, data, offset, seg);
                 if (ret < 0)
                         return ret;
                 offset = 0;
                 len -= seg;
                 data += seg;
                 ++gfn;
         }
         return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_write_guest);
 
 static int __kvm_gfn_to_hva_cache_init(struct kvm_memslots *slots,
                                        struct gfn_to_hva_cache *ghc,
                                        gpa_t gpa, unsigned long len)
 {
         int offset = offset_in_page(gpa);
         gfn_t start_gfn = gpa >> PAGE_SHIFT;
         gfn_t end_gfn = (gpa + len - 1) >> PAGE_SHIFT;
         gfn_t nr_pages_needed = end_gfn - start_gfn + 1;
         gfn_t nr_pages_avail;
         int r = start_gfn <= end_gfn ? 0 : -EINVAL;
 
         ghc->gpa = gpa;
         ghc->generation = slots->generation;
         ghc->len = len;
         ghc->hva = KVM_HVA_ERR_BAD;
 
         /*
          * If the requested region crosses two memslots, we still
          * verify that the entire region is valid here.
          */
         while (!r && start_gfn <= end_gfn) {
                 ghc->memslot = __gfn_to_memslot(slots, start_gfn);
                 ghc->hva = gfn_to_hva_many(ghc->memslot, start_gfn,
                                            &nr_pages_avail);
                 if (kvm_is_error_hva(ghc->hva))
                         r = -EFAULT;
                 start_gfn += nr_pages_avail;
         }
 
         /* Use the slow path for cross page reads and writes. */
         if (!r && nr_pages_needed == 1)
                 ghc->hva += offset;
         else
                 ghc->memslot = NULL;
 
         return r;
 }
 
 int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
                               gpa_t gpa, unsigned long len)
 {
         struct kvm_memslots *slots = kvm_memslots(kvm);
         return __kvm_gfn_to_hva_cache_init(slots, ghc, gpa, len);
 }
 EXPORT_SYMBOL_GPL(kvm_gfn_to_hva_cache_init);
 
 int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
                                   void *data, unsigned int offset,
                                   unsigned long len)
 {
         struct kvm_memslots *slots = kvm_memslots(kvm);
         int r;
         gpa_t gpa = ghc->gpa + offset;
 
         BUG_ON(len + offset > ghc->len);
 
         if (slots->generation != ghc->generation)
                 __kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len);
 
         if (unlikely(!ghc->memslot))
                 return kvm_write_guest(kvm, gpa, data, len);
 
         if (kvm_is_error_hva(ghc->hva))
                 return -EFAULT;
 
         r = __copy_to_user((void __user *)ghc->hva + offset, data, len);
         if (r)
                 return -EFAULT;
         mark_page_dirty_in_slot(ghc->memslot, gpa >> PAGE_SHIFT);
 
         return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_write_guest_offset_cached);
 
 int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
                            void *data, unsigned long len)
 {
         return kvm_write_guest_offset_cached(kvm, ghc, data, 0, len);
 }
 EXPORT_SYMBOL_GPL(kvm_write_guest_cached);
 
 int kvm_read_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
                            void *data, unsigned long len)
 {
         struct kvm_memslots *slots = kvm_memslots(kvm);
         int r;
 
         BUG_ON(len > ghc->len);
 
         if (slots->generation != ghc->generation)
                 __kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len);
 
         if (unlikely(!ghc->memslot))
                 return kvm_read_guest(kvm, ghc->gpa, data, len);
 
         if (kvm_is_error_hva(ghc->hva))
                 return -EFAULT;
 
         r = __copy_from_user(data, (void __user *)ghc->hva, len);
         if (r)
                 return -EFAULT;
 
         return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_read_guest_cached);
 
 int kvm_clear_guest_page(struct kvm *kvm, gfn_t gfn, int offset, int len)
 {
         const void *zero_page = (const void *) __va(page_to_phys(ZERO_PAGE(0)));
 
         return kvm_write_guest_page(kvm, gfn, zero_page, offset, len);
 }
 EXPORT_SYMBOL_GPL(kvm_clear_guest_page);
 
 int kvm_clear_guest(struct kvm *kvm, gpa_t gpa, unsigned long len)
 {
         gfn_t gfn = gpa >> PAGE_SHIFT;
         int seg;
         int offset = offset_in_page(gpa);
         int ret;
 
         while ((seg = next_segment(len, offset)) != 0) {
                 ret = kvm_clear_guest_page(kvm, gfn, offset, seg);
                 if (ret < 0)
                         return ret;
                 offset = 0;
                 len -= seg;
                 ++gfn;
         }
         return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_clear_guest);
 
 static void mark_page_dirty_in_slot(struct kvm_memory_slot *memslot,
                                     gfn_t gfn)
 {
         if (memslot && memslot->dirty_bitmap) {
                 unsigned long rel_gfn = gfn - memslot->base_gfn;
 
                 set_bit_le(rel_gfn, memslot->dirty_bitmap);
         }
 }
 
 void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
 {
         struct kvm_memory_slot *memslot;
 
         memslot = gfn_to_memslot(kvm, gfn);
         mark_page_dirty_in_slot(memslot, gfn);
 }
 EXPORT_SYMBOL_GPL(mark_page_dirty);
 
 void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn)
 {
         struct kvm_memory_slot *memslot;
 
         memslot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
         mark_page_dirty_in_slot(memslot, gfn);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_mark_page_dirty);
 
 void kvm_sigset_activate(struct kvm_vcpu *vcpu)
 {
         if (!vcpu->sigset_active)
                 return;
 
         /*
          * This does a lockless modification of ->real_blocked, which is fine
          * because, only current can change ->real_blocked and all readers of
          * ->real_blocked don't care as long ->real_blocked is always a subset
          * of ->blocked.
          */
         sigprocmask(SIG_SETMASK, &vcpu->sigset, &current->real_blocked);
 }
 
 void kvm_sigset_deactivate(struct kvm_vcpu *vcpu)
 {
         if (!vcpu->sigset_active)
                 return;
 
         sigprocmask(SIG_SETMASK, &current->real_blocked, NULL);
         sigemptyset(&current->real_blocked);
 }
 
 static void grow_halt_poll_ns(struct kvm_vcpu *vcpu)
 {
         unsigned int old, val, grow;
 
         old = val = vcpu->halt_poll_ns;
         grow = READ_ONCE(halt_poll_ns_grow);
         /* 10us base */
         if (val == 0 && grow)
                 val = 10000;
         else
                 val *= grow;
 
         if (val > halt_poll_ns)
                 val = halt_poll_ns;
 
         vcpu->halt_poll_ns = val;
         trace_kvm_halt_poll_ns_grow(vcpu->vcpu_id, val, old);
 }
 
 static void shrink_halt_poll_ns(struct kvm_vcpu *vcpu)
 {
         unsigned int old, val, shrink;
 
         old = val = vcpu->halt_poll_ns;
         shrink = READ_ONCE(halt_poll_ns_shrink);
         if (shrink == 0)
                 val = 0;
         else
                 val /= shrink;
 
         vcpu->halt_poll_ns = val;
         trace_kvm_halt_poll_ns_shrink(vcpu->vcpu_id, val, old);
 }
 
 static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu)
 {
         int ret = -EINTR;
         int idx = srcu_read_lock(&vcpu->kvm->srcu);
 
         if (kvm_arch_vcpu_runnable(vcpu)) {
                 kvm_make_request(KVM_REQ_UNHALT, vcpu);
                 goto out;
         }
         if (kvm_cpu_has_pending_timer(vcpu))
                 goto out;
         if (signal_pending(current))
                 goto out;
 
         ret = 0;
 out:
         srcu_read_unlock(&vcpu->kvm->srcu, idx);
         return ret;
 }
 
 /*
  * The vCPU has executed a HLT instruction with in-kernel mode enabled.
  */
 void kvm_vcpu_block(struct kvm_vcpu *vcpu)
 {
         ktime_t start, cur;
         DECLARE_SWAITQUEUE(wait);
         bool waited = false;
         u64 block_ns;
 
         start = cur = ktime_get();
         if (vcpu->halt_poll_ns) {
                 ktime_t stop = ktime_add_ns(ktime_get(), vcpu->halt_poll_ns);
 
                 ++vcpu->stat.halt_attempted_poll;
                 do {
                         /*
                          * This sets KVM_REQ_UNHALT if an interrupt
                          * arrives.
                          */
                         if (kvm_vcpu_check_block(vcpu) < 0) {
                                 ++vcpu->stat.halt_successful_poll;
                                 if (!vcpu_valid_wakeup(vcpu))
                                         ++vcpu->stat.halt_poll_invalid;
                                 goto out;
                         }
                         cur = ktime_get();
                 } while (single_task_running() && ktime_before(cur, stop));
         }
 
         kvm_arch_vcpu_blocking(vcpu);
 
         for (;;) {
                 prepare_to_swait_exclusive(&vcpu->wq, &wait, TASK_INTERRUPTIBLE);
 
                 if (kvm_vcpu_check_block(vcpu) < 0)
                         break;
 
                 waited = true;
                 schedule();
         }
 
         finish_swait(&vcpu->wq, &wait);
         cur = ktime_get();
 
         kvm_arch_vcpu_unblocking(vcpu);
 out:
         block_ns = ktime_to_ns(cur) - ktime_to_ns(start);
 
         if (!vcpu_valid_wakeup(vcpu))
                 shrink_halt_poll_ns(vcpu);
         else if (halt_poll_ns) {
                 if (block_ns <= vcpu->halt_poll_ns)
                         ;
                 /* we had a long block, shrink polling */
                 else if (vcpu->halt_poll_ns && block_ns > halt_poll_ns)
                         shrink_halt_poll_ns(vcpu);
                 /* we had a short halt and our poll time is too small */
                 else if (vcpu->halt_poll_ns < halt_poll_ns &&
                         block_ns < halt_poll_ns)
                         grow_halt_poll_ns(vcpu);
         } else
                 vcpu->halt_poll_ns = 0;
 
         trace_kvm_vcpu_wakeup(block_ns, waited, vcpu_valid_wakeup(vcpu));
         kvm_arch_vcpu_block_finish(vcpu);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_block);
 
 bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu)
 {
         struct swait_queue_head *wqp;
 
         wqp = kvm_arch_vcpu_wq(vcpu);
         if (swq_has_sleeper(wqp)) {
                 swake_up_one(wqp);
                 ++vcpu->stat.halt_wakeup;
                 return true;
         }
 
         return false;
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_wake_up);
 
 #ifndef CONFIG_S390
 /*
  * Kick a sleeping VCPU, or a guest VCPU in guest mode, into host kernel mode.
  */
 void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
 {
         int me;
         int cpu = vcpu->cpu;
 
         if (kvm_vcpu_wake_up(vcpu))
                 return;
 
         me = get_cpu();
         if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu))
                 if (kvm_arch_vcpu_should_kick(vcpu))
                         smp_send_reschedule(cpu);
         put_cpu();
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_kick);
 #endif /* !CONFIG_S390 */
 
 int kvm_vcpu_yield_to(struct kvm_vcpu *target)
 {
         struct pid *pid;
         struct task_struct *task = NULL;
         int ret = 0;
 
         rcu_read_lock();
         pid = rcu_dereference(target->pid);
         if (pid)
                 task = get_pid_task(pid, PIDTYPE_PID);
         rcu_read_unlock();
         if (!task)
                 return ret;
         ret = yield_to(task, 1);
         put_task_struct(task);
 
         return ret;
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_yield_to);
 
 /*
  * Helper that checks whether a VCPU is eligible for directed yield.
  * Most eligible candidate to yield is decided by following heuristics:
  *
  *  (a) VCPU which has not done pl-exit or cpu relax intercepted recently
  *  (preempted lock holder), indicated by @in_spin_loop.
  *  Set at the beiginning and cleared at the end of interception/PLE handler.
  *
  *  (b) VCPU which has done pl-exit/ cpu relax intercepted but did not get
  *  chance last time (mostly it has become eligible now since we have probably
  *  yielded to lockholder in last iteration. This is done by toggling
  *  @dy_eligible each time a VCPU checked for eligibility.)
  *
  *  Yielding to a recently pl-exited/cpu relax intercepted VCPU before yielding
  *  to preempted lock-holder could result in wrong VCPU selection and CPU
  *  burning. Giving priority for a potential lock-holder increases lock
  *  progress.
  *
  *  Since algorithm is based on heuristics, accessing another VCPU data without
  *  locking does not harm. It may result in trying to yield to  same VCPU, fail
  *  and continue with next VCPU and so on.
  */
 static bool kvm_vcpu_eligible_for_directed_yield(struct kvm_vcpu *vcpu)
 {
 #ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT
         bool eligible;
 
         eligible = !vcpu->spin_loop.in_spin_loop ||
                     vcpu->spin_loop.dy_eligible;
 
         if (vcpu->spin_loop.in_spin_loop)
                 kvm_vcpu_set_dy_eligible(vcpu, !vcpu->spin_loop.dy_eligible);
 
         return eligible;
 #else
         return true;
 #endif
 }
 
 void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode)
 {
         struct kvm *kvm = me->kvm;
         struct kvm_vcpu *vcpu;
         int last_boosted_vcpu = me->kvm->last_boosted_vcpu;
         int yielded = 0;
         int try = 3;
         int pass;
         int i;
 
         kvm_vcpu_set_in_spin_loop(me, true);
         /*
          * We boost the priority of a VCPU that is runnable but not
          * currently running, because it got preempted by something
          * else and called schedule in __vcpu_run.  Hopefully that
          * VCPU is holding the lock that we need and will release it.
          * We approximate round-robin by starting at the last boosted VCPU.
          */
         for (pass = 0; pass < 2 && !yielded && try; pass++) {
                 kvm_for_each_vcpu(i, vcpu, kvm) {
                         if (!pass && i <= last_boosted_vcpu) {
                                 i = last_boosted_vcpu;
                                 continue;
                         } else if (pass && i > last_boosted_vcpu)
                                 break;
                         if (!READ_ONCE(vcpu->preempted))
                                 continue;
                         if (vcpu == me)
                                 continue;
                         if (swait_active(&vcpu->wq) && !kvm_arch_vcpu_runnable(vcpu))
                                 continue;
                         if (yield_to_kernel_mode && !kvm_arch_vcpu_in_kernel(vcpu))
                                 continue;
                         if (!kvm_vcpu_eligible_for_directed_yield(vcpu))
                                 continue;
 
                         yielded = kvm_vcpu_yield_to(vcpu);
                         if (yielded > 0) {
                                 kvm->last_boosted_vcpu = i;
                                 break;
                         } else if (yielded < 0) {
                                 try--;
                                 if (!try)
                                         break;
                         }
                 }
         }
         kvm_vcpu_set_in_spin_loop(me, false);
 
         /* Ensure vcpu is not eligible during next spinloop */
         kvm_vcpu_set_dy_eligible(me, false);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_on_spin);
 
 static vm_fault_t kvm_vcpu_fault(struct vm_fault *vmf)
 {
         struct kvm_vcpu *vcpu = vmf->vma->vm_file->private_data;
         struct page *page;
 
         if (vmf->pgoff == 0)
                 page = virt_to_page(vcpu->run);
 #ifdef CONFIG_X86
         else if (vmf->pgoff == KVM_PIO_PAGE_OFFSET)
                 page = virt_to_page(vcpu->arch.pio_data);
 #endif
 #ifdef CONFIG_KVM_MMIO
         else if (vmf->pgoff == KVM_COALESCED_MMIO_PAGE_OFFSET)
                 page = virt_to_page(vcpu->kvm->coalesced_mmio_ring);
 #endif
         else
                 return kvm_arch_vcpu_fault(vcpu, vmf);
         get_page(page);
         vmf->page = page;
         return 0;
 }
 
 static const struct vm_operations_struct kvm_vcpu_vm_ops = {
         .fault = kvm_vcpu_fault,
 };
 
 static int kvm_vcpu_mmap(struct file *file, struct vm_area_struct *vma)
 {
         vma->vm_ops = &kvm_vcpu_vm_ops;
         return 0;
 }
 
 static int kvm_vcpu_release(struct inode *inode, struct file *filp)
 {
         struct kvm_vcpu *vcpu = filp->private_data;
 
         debugfs_remove_recursive(vcpu->debugfs_dentry);
         kvm_put_kvm(vcpu->kvm);
         return 0;
 }
 
 static struct file_operations kvm_vcpu_fops = {
         .release        = kvm_vcpu_release,
         .unlocked_ioctl = kvm_vcpu_ioctl,
         .mmap           = kvm_vcpu_mmap,
         .llseek         = noop_llseek,
         KVM_COMPAT(kvm_vcpu_compat_ioctl),
 };
 
 /*
  * Allocates an inode for the vcpu.
  */
 static int create_vcpu_fd(struct kvm_vcpu *vcpu)
 {
         char name[8 + 1 + ITOA_MAX_LEN + 1];
 
         snprintf(name, sizeof(name), "kvm-vcpu:%d", vcpu->vcpu_id);
         return anon_inode_getfd(name, &kvm_vcpu_fops, vcpu, O_RDWR | O_CLOEXEC);
 }
 
 static int kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu)
 {
         char dir_name[ITOA_MAX_LEN * 2];
         int ret;
 
         if (!kvm_arch_has_vcpu_debugfs())
                 return 0;
 
         if (!debugfs_initialized())
                 return 0;
 
         snprintf(dir_name, sizeof(dir_name), "vcpu%d", vcpu->vcpu_id);
         vcpu->debugfs_dentry = debugfs_create_dir(dir_name,
                                                                 vcpu->kvm->debugfs_dentry);
         if (!vcpu->debugfs_dentry)
                 return -ENOMEM;
 
         ret = kvm_arch_create_vcpu_debugfs(vcpu);
         if (ret < 0) {
                 debugfs_remove_recursive(vcpu->debugfs_dentry);
                 return ret;
         }
 
         return 0;
 }
 
 /*
  * Creates some virtual cpus.  Good luck creating more than one.
  */
 static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
 {
         int r;
         struct kvm_vcpu *vcpu;
 
         if (id >= KVM_MAX_VCPU_ID)
                 return -EINVAL;
 
         mutex_lock(&kvm->lock);
         if (kvm->created_vcpus == KVM_MAX_VCPUS) {
                 mutex_unlock(&kvm->lock);
                 return -EINVAL;
         }
 
         kvm->created_vcpus++;
         mutex_unlock(&kvm->lock);
 
         vcpu = kvm_arch_vcpu_create(kvm, id);
         if (IS_ERR(vcpu)) {
                 r = PTR_ERR(vcpu);
                 goto vcpu_decrement;
         }
 
         preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops);
 
         r = kvm_arch_vcpu_setup(vcpu);
         if (r)
                 goto vcpu_destroy;
 
         r = kvm_create_vcpu_debugfs(vcpu);
         if (r)
                 goto vcpu_destroy;
 
         mutex_lock(&kvm->lock);
         if (kvm_get_vcpu_by_id(kvm, id)) {
                 r = -EEXIST;
                 goto unlock_vcpu_destroy;
         }
 
         BUG_ON(kvm->vcpus[atomic_read(&kvm->online_vcpus)]);
 
         /* Now it's all set up, let userspace reach it */
         kvm_get_kvm(kvm);
         r = create_vcpu_fd(vcpu);
         if (r < 0) {
                 kvm_put_kvm(kvm);
                 goto unlock_vcpu_destroy;
         }
 
         kvm->vcpus[atomic_read(&kvm->online_vcpus)] = vcpu;
 
         /*
          * Pairs with smp_rmb() in kvm_get_vcpu.  Write kvm->vcpus
          * before kvm->online_vcpu's incremented value.
          */
         smp_wmb();
         atomic_inc(&kvm->online_vcpus);
 
         mutex_unlock(&kvm->lock);
         kvm_arch_vcpu_postcreate(vcpu);
         return r;
 
 unlock_vcpu_destroy:
         mutex_unlock(&kvm->lock);
         debugfs_remove_recursive(vcpu->debugfs_dentry);
 vcpu_destroy:
         kvm_arch_vcpu_destroy(vcpu);
 vcpu_decrement:
         mutex_lock(&kvm->lock);
         kvm->created_vcpus--;
         mutex_unlock(&kvm->lock);
         return r;
 }
 
 static int kvm_vcpu_ioctl_set_sigmask(struct kvm_vcpu *vcpu, sigset_t *sigset)
 {
         if (sigset) {
                 sigdelsetmask(sigset, sigmask(SIGKILL)|sigmask(SIGSTOP));
                 vcpu->sigset_active = 1;
                 vcpu->sigset = *sigset;
         } else
                 vcpu->sigset_active = 0;
         return 0;
 }
 
 static long kvm_vcpu_ioctl(struct file *filp,
                            unsigned int ioctl, unsigned long arg)
 {
         struct kvm_vcpu *vcpu = filp->private_data;
         void __user *argp = (void __user *)arg;
         int r;
         struct kvm_fpu *fpu = NULL;
         struct kvm_sregs *kvm_sregs = NULL;
 
         if (vcpu->kvm->mm != current->mm)
                 return -EIO;
 
         if (unlikely(_IOC_TYPE(ioctl) != KVMIO))
                 return -EINVAL;
 
         /*
          * Some architectures have vcpu ioctls that are asynchronous to vcpu
          * execution; mutex_lock() would break them.
          */
         r = kvm_arch_vcpu_async_ioctl(filp, ioctl, arg);
         if (r != -ENOIOCTLCMD)
                 return r;
 
         if (mutex_lock_killable(&vcpu->mutex))
                 return -EINTR;
         switch (ioctl) {
         case KVM_RUN: {
                 struct pid *oldpid;
                 r = -EINVAL;
                 if (arg)
                         goto out;
                 oldpid = rcu_access_pointer(vcpu->pid);
                 if (unlikely(oldpid != task_pid(current))) {
                         /* The thread running this VCPU changed. */
                         struct pid *newpid;
 
                         r = kvm_arch_vcpu_run_pid_change(vcpu);
                         if (r)
                                 break;
 
                         newpid = get_task_pid(current, PIDTYPE_PID);
                         rcu_assign_pointer(vcpu->pid, newpid);
                         if (oldpid)
                                 synchronize_rcu();
                         put_pid(oldpid);
                 }
                 r = kvm_arch_vcpu_ioctl_run(vcpu, vcpu->run);
                 trace_kvm_userspace_exit(vcpu->run->exit_reason, r);
                 break;
         }
         case KVM_GET_REGS: {
                 struct kvm_regs *kvm_regs;
 
                 r = -ENOMEM;
                 kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL);
                 if (!kvm_regs)
                         goto out;
                 r = kvm_arch_vcpu_ioctl_get_regs(vcpu, kvm_regs);
                 if (r)
                         goto out_free1;
                 r = -EFAULT;
                 if (copy_to_user(argp, kvm_regs, sizeof(struct kvm_regs)))
                         goto out_free1;
                 r = 0;
 out_free1:
                 kfree(kvm_regs);
                 break;
         }
         case KVM_SET_REGS: {
                 struct kvm_regs *kvm_regs;
 
                 r = -ENOMEM;
                 kvm_regs = memdup_user(argp, sizeof(*kvm_regs));
                 if (IS_ERR(kvm_regs)) {
                         r = PTR_ERR(kvm_regs);
                         goto out;
                 }
                 r = kvm_arch_vcpu_ioctl_set_regs(vcpu, kvm_regs);
                 kfree(kvm_regs);
                 break;
         }
         case KVM_GET_SREGS: {
                 kvm_sregs = kzalloc(sizeof(struct kvm_sregs), GFP_KERNEL);
                 r = -ENOMEM;
                 if (!kvm_sregs)
                         goto out;
                 r = kvm_arch_vcpu_ioctl_get_sregs(vcpu, kvm_sregs);
                 if (r)
                         goto out;
                 r = -EFAULT;
                 if (copy_to_user(argp, kvm_sregs, sizeof(struct kvm_sregs)))
                         goto out;
                 r = 0;
                 break;
         }
         case KVM_SET_SREGS: {
                 kvm_sregs = memdup_user(argp, sizeof(*kvm_sregs));
                 if (IS_ERR(kvm_sregs)) {
                         r = PTR_ERR(kvm_sregs);
                         kvm_sregs = NULL;
                         goto out;
                 }
                 r = kvm_arch_vcpu_ioctl_set_sregs(vcpu, kvm_sregs);
                 break;
         }
         case KVM_GET_MP_STATE: {
                 struct kvm_mp_state mp_state;
 
                 r = kvm_arch_vcpu_ioctl_get_mpstate(vcpu, &mp_state);
                 if (r)
                         goto out;
                 r = -EFAULT;
                 if (copy_to_user(argp, &mp_state, sizeof(mp_state)))
                         goto out;
                 r = 0;
                 break;
         }
         case KVM_SET_MP_STATE: {
                 struct kvm_mp_state mp_state;
 
                 r = -EFAULT;
                 if (copy_from_user(&mp_state, argp, sizeof(mp_state)))
                         goto out;
                 r = kvm_arch_vcpu_ioctl_set_mpstate(vcpu, &mp_state);
                 break;
         }
         case KVM_TRANSLATE: {
                 struct kvm_translation tr;
 
                 r = -EFAULT;
                 if (copy_from_user(&tr, argp, sizeof(tr)))
                         goto out;
                 r = kvm_arch_vcpu_ioctl_translate(vcpu, &tr);
                 if (r)
                         goto out;
                 r = -EFAULT;
                 if (copy_to_user(argp, &tr, sizeof(tr)))
                         goto out;
                 r = 0;
                 break;
         }
         case KVM_SET_GUEST_DEBUG: {
                 struct kvm_guest_debug dbg;
 
                 r = -EFAULT;
                 if (copy_from_user(&dbg, argp, sizeof(dbg)))
                         goto out;
                 r = kvm_arch_vcpu_ioctl_set_guest_debug(vcpu, &dbg);
                 break;
         }
         case KVM_SET_SIGNAL_MASK: {
                 struct kvm_signal_mask __user *sigmask_arg = argp;
                 struct kvm_signal_mask kvm_sigmask;
                 sigset_t sigset, *p;
 
                 p = NULL;
                 if (argp) {
                         r = -EFAULT;
                         if (copy_from_user(&kvm_sigmask, argp,
                                            sizeof(kvm_sigmask)))
                                 goto out;
                         r = -EINVAL;
                         if (kvm_sigmask.len != sizeof(sigset))
                                 goto out;
                         r = -EFAULT;
                         if (copy_from_user(&sigset, sigmask_arg->sigset,
                                            sizeof(sigset)))
                                 goto out;
                         p = &sigset;
                 }
                 r = kvm_vcpu_ioctl_set_sigmask(vcpu, p);
                 break;
         }
         case KVM_GET_FPU: {
                 fpu = kzalloc(sizeof(struct kvm_fpu), GFP_KERNEL);
                 r = -ENOMEM;
                 if (!fpu)
                         goto out;
                 r = kvm_arch_vcpu_ioctl_get_fpu(vcpu, fpu);
                 if (r)
                         goto out;
                 r = -EFAULT;
                 if (copy_to_user(argp, fpu, sizeof(struct kvm_fpu)))
                         goto out;
                 r = 0;
                 break;
         }
         case KVM_SET_FPU: {
                 fpu = memdup_user(argp, sizeof(*fpu));
                 if (IS_ERR(fpu)) {
                         r = PTR_ERR(fpu);
                         fpu = NULL;
                         goto out;
                 }
                 r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, fpu);
                 break;
         }
         default:
                 r = kvm_arch_vcpu_ioctl(filp, ioctl, arg);
         }
 out:
         mutex_unlock(&vcpu->mutex);
         kfree(fpu);
         kfree(kvm_sregs);
         return r;
 }
 
 #ifdef CONFIG_KVM_COMPAT
 static long kvm_vcpu_compat_ioctl(struct file *filp,
                                   unsigned int ioctl, unsigned long arg)
 {
         struct kvm_vcpu *vcpu = filp->private_data;
         void __user *argp = compat_ptr(arg);
         int r;
 
         if (vcpu->kvm->mm != current->mm)
                 return -EIO;
 
         switch (ioctl) {
         case KVM_SET_SIGNAL_MASK: {
                 struct kvm_signal_mask __user *sigmask_arg = argp;
                 struct kvm_signal_mask kvm_sigmask;
                 sigset_t sigset;
 
                 if (argp) {
                         r = -EFAULT;
                         if (copy_from_user(&kvm_sigmask, argp,
                                            sizeof(kvm_sigmask)))
                                 goto out;
                         r = -EINVAL;
                         if (kvm_sigmask.len != sizeof(compat_sigset_t))
                                 goto out;
                         r = -EFAULT;
                         if (get_compat_sigset(&sigset, (void *)sigmask_arg->sigset))
                                 goto out;
                         r = kvm_vcpu_ioctl_set_sigmask(vcpu, &sigset);
                 } else
                         r = kvm_vcpu_ioctl_set_sigmask(vcpu, NULL);
                 break;
         }
         default:
                 r = kvm_vcpu_ioctl(filp, ioctl, arg);
         }
 
 out:
         return r;
 }
 #endif
 
 static int kvm_device_ioctl_attr(struct kvm_device *dev,
                                  int (*accessor)(struct kvm_device *dev,
                                                  struct kvm_device_attr *attr),
                                  unsigned long arg)
 {
         struct kvm_device_attr attr;
 
         if (!accessor)
                 return -EPERM;
 
         if (copy_from_user(&attr, (void __user *)arg, sizeof(attr)))
                 return -EFAULT;
 
         return accessor(dev, &attr);
 }
 
 static long kvm_device_ioctl(struct file *filp, unsigned int ioctl,
                              unsigned long arg)
 {
         struct kvm_device *dev = filp->private_data;
 
         if (dev->kvm->mm != current->mm)
                 return -EIO;
 
         switch (ioctl) {
         case KVM_SET_DEVICE_ATTR:
                 return kvm_device_ioctl_attr(dev, dev->ops->set_attr, arg);
         case KVM_GET_DEVICE_ATTR:
                 return kvm_device_ioctl_attr(dev, dev->ops->get_attr, arg);
         case KVM_HAS_DEVICE_ATTR:
                 return kvm_device_ioctl_attr(dev, dev->ops->has_attr, arg);
         default:
                 if (dev->ops->ioctl)
                         return dev->ops->ioctl(dev, ioctl, arg);
 
                 return -ENOTTY;
         }
 }
 
 static int kvm_device_release(struct inode *inode, struct file *filp)
 {
         struct kvm_device *dev = filp->private_data;
         struct kvm *kvm = dev->kvm;
 
         kvm_put_kvm(kvm);
         return 0;
 }
 
 static const struct file_operations kvm_device_fops = {
         .unlocked_ioctl = kvm_device_ioctl,
         .release = kvm_device_release,
         KVM_COMPAT(kvm_device_ioctl),
 };
 
 struct kvm_device *kvm_device_from_filp(struct file *filp)
 {
         if (filp->f_op != &kvm_device_fops)
                 return NULL;
 
         return filp->private_data;
 }
 
 static struct kvm_device_ops *kvm_device_ops_table[KVM_DEV_TYPE_MAX] = {
 #ifdef CONFIG_KVM_MPIC
         [KVM_DEV_TYPE_FSL_MPIC_20]      = &kvm_mpic_ops,
         [KVM_DEV_TYPE_FSL_MPIC_42]      = &kvm_mpic_ops,
 #endif
 };
 
 int kvm_register_device_ops(struct kvm_device_ops *ops, u32 type)
 {
         if (type >= ARRAY_SIZE(kvm_device_ops_table))
                 return -ENOSPC;
 
         if (kvm_device_ops_table[type] != NULL)
                 return -EEXIST;
 
         kvm_device_ops_table[type] = ops;
         return 0;
 }
 
 void kvm_unregister_device_ops(u32 type)
 {
         if (kvm_device_ops_table[type] != NULL)
                 kvm_device_ops_table[type] = NULL;
 }
 
 static int kvm_ioctl_create_device(struct kvm *kvm,
                                    struct kvm_create_device *cd)
 {
         struct kvm_device_ops *ops = NULL;
         struct kvm_device *dev;
         bool test = cd->flags & KVM_CREATE_DEVICE_TEST;
         int type;
         int ret;
 
         if (cd->type >= ARRAY_SIZE(kvm_device_ops_table))
                 return -ENODEV;
 
         type = array_index_nospec(cd->type, ARRAY_SIZE(kvm_device_ops_table));
         ops = kvm_device_ops_table[type];
         if (ops == NULL)
                 return -ENODEV;
 
         if (test)
                 return 0;
 
         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
         if (!dev)
                 return -ENOMEM;
 
         dev->ops = ops;
         dev->kvm = kvm;
 
         mutex_lock(&kvm->lock);
         ret = ops->create(dev, type);
         if (ret < 0) {
                 mutex_unlock(&kvm->lock);
                 kfree(dev);
                 return ret;
         }
         list_add(&dev->vm_node, &kvm->devices);
         mutex_unlock(&kvm->lock);
 
         if (ops->init)
                 ops->init(dev);
 
         kvm_get_kvm(kvm);
         ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC);
         if (ret < 0) {
                 kvm_put_kvm(kvm);
                 mutex_lock(&kvm->lock);
                 list_del(&dev->vm_node);
                 mutex_unlock(&kvm->lock);
                 ops->destroy(dev);
                 return ret;
         }
 
         cd->fd = ret;
         return 0;
 }
 
 static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
 {
         switch (arg) {
         case KVM_CAP_USER_MEMORY:
         case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
         case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS:
         case KVM_CAP_INTERNAL_ERROR_DATA:
 #ifdef CONFIG_HAVE_KVM_MSI
         case KVM_CAP_SIGNAL_MSI:
 #endif
 #ifdef CONFIG_HAVE_KVM_IRQFD
         case KVM_CAP_IRQFD:
         case KVM_CAP_IRQFD_RESAMPLE:
 #endif
         case KVM_CAP_IOEVENTFD_ANY_LENGTH:
         case KVM_CAP_CHECK_EXTENSION_VM:
         case KVM_CAP_ENABLE_CAP_VM:
 #ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
         case KVM_CAP_MANUAL_DIRTY_LOG_PROTECT:
 #endif
                 return 1;
 #ifdef CONFIG_KVM_MMIO
         case KVM_CAP_COALESCED_MMIO:
                 return KVM_COALESCED_MMIO_PAGE_OFFSET;
         case KVM_CAP_COALESCED_PIO:
                 return 1;
 #endif
 #ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
         case KVM_CAP_IRQ_ROUTING:
                 return KVM_MAX_IRQ_ROUTES;
 #endif
 #if KVM_ADDRESS_SPACE_NUM > 1
         case KVM_CAP_MULTI_ADDRESS_SPACE:
                 return KVM_ADDRESS_SPACE_NUM;
 #endif
         case KVM_CAP_MAX_VCPU_ID:
                 return KVM_MAX_VCPU_ID;
         default:
                 break;
         }
         return kvm_vm_ioctl_check_extension(kvm, arg);
 }
 
 int __attribute__((weak)) kvm_vm_ioctl_enable_cap(struct kvm *kvm,
                                                   struct kvm_enable_cap *cap)
 {
         return -EINVAL;
 }
 
 static int kvm_vm_ioctl_enable_cap_generic(struct kvm *kvm,
                                            struct kvm_enable_cap *cap)
 {
         switch (cap->cap) {
 #ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
         case KVM_CAP_MANUAL_DIRTY_LOG_PROTECT:
                 if (cap->flags || (cap->args[0] & ~1))
                         return -EINVAL;
                 kvm->manual_dirty_log_protect = cap->args[0];
                 return 0;
 #endif
         default:
                 return kvm_vm_ioctl_enable_cap(kvm, cap);
         }
 }
 
 static long kvm_vm_ioctl(struct file *filp,
                            unsigned int ioctl, unsigned long arg)
 {
         struct kvm *kvm = filp->private_data;
         void __user *argp = (void __user *)arg;
         int r;
 
         if (kvm->mm != current->mm)
                 return -EIO;
         switch (ioctl) {
         case KVM_CREATE_VCPU:
                 r = kvm_vm_ioctl_create_vcpu(kvm, arg);
                 break;
         case KVM_ENABLE_CAP: {
                 struct kvm_enable_cap cap;
 
                 r = -EFAULT;
                 if (copy_from_user(&cap, argp, sizeof(cap)))
                         goto out;
                 r = kvm_vm_ioctl_enable_cap_generic(kvm, &cap);
                 break;
         }
         case KVM_SET_USER_MEMORY_REGION: {
                 struct kvm_userspace_memory_region kvm_userspace_mem;
 
                 r = -EFAULT;
                 if (copy_from_user(&kvm_userspace_mem, argp,
                                                 sizeof(kvm_userspace_mem)))
                         goto out;
 
                 r = kvm_vm_ioctl_set_memory_region(kvm, &kvm_userspace_mem);
                 break;
         }
         case KVM_GET_DIRTY_LOG: {
                 struct kvm_dirty_log log;
 
                 r = -EFAULT;
                 if (copy_from_user(&log, argp, sizeof(log)))
                         goto out;
                 r = kvm_vm_ioctl_get_dirty_log(kvm, &log);
                 break;
         }
 #ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
         case KVM_CLEAR_DIRTY_LOG: {
                 struct kvm_clear_dirty_log log;
 
                 r = -EFAULT;
                 if (copy_from_user(&log, argp, sizeof(log)))
                         goto out;
                 r = kvm_vm_ioctl_clear_dirty_log(kvm, &log);
                 break;
         }
 #endif
 #ifdef CONFIG_KVM_MMIO
         case KVM_REGISTER_COALESCED_MMIO: {
                 struct kvm_coalesced_mmio_zone zone;
 
                 r = -EFAULT;
                 if (copy_from_user(&zone, argp, sizeof(zone)))
                         goto out;
                 r = kvm_vm_ioctl_register_coalesced_mmio(kvm, &zone);
                 break;
         }
         case KVM_UNREGISTER_COALESCED_MMIO: {
                 struct kvm_coalesced_mmio_zone zone;
 
                 r = -EFAULT;
                 if (copy_from_user(&zone, argp, sizeof(zone)))
                         goto out;
                 r = kvm_vm_ioctl_unregister_coalesced_mmio(kvm, &zone);
                 break;
         }
 #endif
         case KVM_IRQFD: {
                 struct kvm_irqfd data;
 
                 r = -EFAULT;
                 if (copy_from_user(&data, argp, sizeof(data)))
                         goto out;
                 r = kvm_irqfd(kvm, &data);
                 break;
         }
         case KVM_IOEVENTFD: {
                 struct kvm_ioeventfd data;
 
                 r = -EFAULT;
                 if (copy_from_user(&data, argp, sizeof(data)))
                         goto out;
                 r = kvm_ioeventfd(kvm, &data);
                 break;
         }
 #ifdef CONFIG_HAVE_KVM_MSI
         case KVM_SIGNAL_MSI: {
                 struct kvm_msi msi;
 
                 r = -EFAULT;
                 if (copy_from_user(&msi, argp, sizeof(msi)))
                         goto out;
                 r = kvm_send_userspace_msi(kvm, &msi);
                 break;
         }
 #endif
 #ifdef __KVM_HAVE_IRQ_LINE
         case KVM_IRQ_LINE_STATUS:
         case KVM_IRQ_LINE: {
                 struct kvm_irq_level irq_event;
 
                 r = -EFAULT;
                 if (copy_from_user(&irq_event, argp, sizeof(irq_event)))
                         goto out;
 
                 r = kvm_vm_ioctl_irq_line(kvm, &irq_event,
                                         ioctl == KVM_IRQ_LINE_STATUS);
                 if (r)
                         goto out;
 
                 r = -EFAULT;
                 if (ioctl == KVM_IRQ_LINE_STATUS) {
                         if (copy_to_user(argp, &irq_event, sizeof(irq_event)))
                                 goto out;
                 }
 
                 r = 0;
                 break;
         }
 #endif
 #ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
         case KVM_SET_GSI_ROUTING: {
                 struct kvm_irq_routing routing;
                 struct kvm_irq_routing __user *urouting;
                 struct kvm_irq_routing_entry *entries = NULL;
 
                 r = -EFAULT;
                 if (copy_from_user(&routing, argp, sizeof(routing)))
                         goto out;
                 r = -EINVAL;
                 if (!kvm_arch_can_set_irq_routing(kvm))
                         goto out;
                 if (routing.nr > KVM_MAX_IRQ_ROUTES)
                         goto out;
                 if (routing.flags)
                         goto out;
                 if (routing.nr) {
                         r = -ENOMEM;
                         entries = vmalloc(array_size(sizeof(*entries),
                                                      routing.nr));
                         if (!entries)
                                 goto out;
                         r = -EFAULT;
                         urouting = argp;
                         if (copy_from_user(entries, urouting->entries,
                                            routing.nr * sizeof(*entries)))
                                 goto out_free_irq_routing;
                 }
                 r = kvm_set_irq_routing(kvm, entries, routing.nr,
                                         routing.flags);
 out_free_irq_routing:
                 vfree(entries);
                 break;
         }
 #endif /* CONFIG_HAVE_KVM_IRQ_ROUTING */
         case KVM_CREATE_DEVICE: {
                 struct kvm_create_device cd;
 
                 r = -EFAULT;
                 if (copy_from_user(&cd, argp, sizeof(cd)))
                         goto out;
 
                 r = kvm_ioctl_create_device(kvm, &cd);
                 if (r)
                         goto out;
 
                 r = -EFAULT;
                 if (copy_to_user(argp, &cd, sizeof(cd)))
                         goto out;
 
                 r = 0;
                 break;
         }
         case KVM_CHECK_EXTENSION:
                 r = kvm_vm_ioctl_check_extension_generic(kvm, arg);
                 break;
         default:
                 r = kvm_arch_vm_ioctl(filp, ioctl, arg);
         }
 out:
         return r;
 }
 
 #ifdef CONFIG_KVM_COMPAT
 struct compat_kvm_dirty_log {
         __u32 slot;
         __u32 padding1;
         union {
                 compat_uptr_t dirty_bitmap; /* one bit per page */
                 __u64 padding2;
         };
 };
 
 static long kvm_vm_compat_ioctl(struct file *filp,
                            unsigned int ioctl, unsigned long arg)
 {
         struct kvm *kvm = filp->private_data;
         int r;
 
         if (kvm->mm != current->mm)
                 return -EIO;
         switch (ioctl) {
         case KVM_GET_DIRTY_LOG: {
                 struct compat_kvm_dirty_log compat_log;
                 struct kvm_dirty_log log;
 
                 if (copy_from_user(&compat_log, (void __user *)arg,
                                    sizeof(compat_log)))
                         return -EFAULT;
                 log.slot         = compat_log.slot;
                 log.padding1     = compat_log.padding1;
                 log.padding2     = compat_log.padding2;
                 log.dirty_bitmap = compat_ptr(compat_log.dirty_bitmap);
 
                 r = kvm_vm_ioctl_get_dirty_log(kvm, &log);
                 break;
         }
         default:
                 r = kvm_vm_ioctl(filp, ioctl, arg);
         }
         return r;
 }
 #endif
 
 static struct file_operations kvm_vm_fops = {
         .release        = kvm_vm_release,
         .unlocked_ioctl = kvm_vm_ioctl,
         .llseek         = noop_llseek,
         KVM_COMPAT(kvm_vm_compat_ioctl),
 };
 
 static int kvm_dev_ioctl_create_vm(unsigned long type)
 {
         int r;
         struct kvm *kvm;
         struct file *file;
 
         kvm = kvm_create_vm(type);
         if (IS_ERR(kvm))
                 return PTR_ERR(kvm);
 #ifdef CONFIG_KVM_MMIO
         r = kvm_coalesced_mmio_init(kvm);
         if (r < 0)
                 goto put_kvm;
 #endif
         r = get_unused_fd_flags(O_CLOEXEC);
         if (r < 0)
                 goto put_kvm;
 
         file = anon_inode_getfile("kvm-vm", &kvm_vm_fops, kvm, O_RDWR);
         if (IS_ERR(file)) {
                 put_unused_fd(r);
                 r = PTR_ERR(file);
                 goto put_kvm;
         }
 
         /*
          * Don't call kvm_put_kvm anymore at this point; file->f_op is
          * already set, with ->release() being kvm_vm_release().  In error
          * cases it will be called by the final fput(file) and will take
          * care of doing kvm_put_kvm(kvm).
          */
         if (kvm_create_vm_debugfs(kvm, r) < 0) {
                 put_unused_fd(r);
                 fput(file);
                 return -ENOMEM;
         }
         kvm_uevent_notify_change(KVM_EVENT_CREATE_VM, kvm);
 
         fd_install(r, file);
         return r;
 
 put_kvm:
         kvm_put_kvm(kvm);
         return r;
 }
 
 static long kvm_dev_ioctl(struct file *filp,
                           unsigned int ioctl, unsigned long arg)
 {
         long r = -EINVAL;
 
         switch (ioctl) {
         case KVM_GET_API_VERSION:
                 if (arg)
                         goto out;
                 r = KVM_API_VERSION;
                 break;
         case KVM_CREATE_VM:
                 r = kvm_dev_ioctl_create_vm(arg);
                 break;
         case KVM_CHECK_EXTENSION:
                 r = kvm_vm_ioctl_check_extension_generic(NULL, arg);
                 break;
         case KVM_GET_VCPU_MMAP_SIZE:
                 if (arg)
                         goto out;
                 r = PAGE_SIZE;     /* struct kvm_run */
 #ifdef CONFIG_X86
                 r += PAGE_SIZE;    /* pio data page */
 #endif
 #ifdef CONFIG_KVM_MMIO
                 r += PAGE_SIZE;    /* coalesced mmio ring page */
 #endif
                 break;
         case KVM_TRACE_ENABLE:
         case KVM_TRACE_PAUSE:
         case KVM_TRACE_DISABLE:
                 r = -EOPNOTSUPP;
                 break;
         default:
                 return kvm_arch_dev_ioctl(filp, ioctl, arg);
         }
 out:
         return r;
 }
 
 static struct file_operations kvm_chardev_ops = {
         .unlocked_ioctl = kvm_dev_ioctl,
         .llseek         = noop_llseek,
         KVM_COMPAT(kvm_dev_ioctl),
 };
 
 static struct miscdevice kvm_dev = {
         KVM_MINOR,
         "kvm",
         &kvm_chardev_ops,
 };
 
 static void hardware_enable_nolock(void *junk)
 {
         int cpu = raw_smp_processor_id();
         int r;
 
         if (cpumask_test_cpu(cpu, cpus_hardware_enabled))
                 return;
 
         cpumask_set_cpu(cpu, cpus_hardware_enabled);
 
         r = kvm_arch_hardware_enable();
 
         if (r) {
                 cpumask_clear_cpu(cpu, cpus_hardware_enabled);
                 atomic_inc(&hardware_enable_failed);
                 pr_info("kvm: enabling virtualization on CPU%d failed\n", cpu);
         }
 }
 
 static int kvm_starting_cpu(unsigned int cpu)
 {
         raw_spin_lock(&kvm_count_lock);
         if (kvm_usage_count)
                 hardware_enable_nolock(NULL);
         raw_spin_unlock(&kvm_count_lock);
         return 0;
 }
 
 static void hardware_disable_nolock(void *junk)
 {
         int cpu = raw_smp_processor_id();
 
         if (!cpumask_test_cpu(cpu, cpus_hardware_enabled))
                 return;
         cpumask_clear_cpu(cpu, cpus_hardware_enabled);
         kvm_arch_hardware_disable();
 }
 
 static int kvm_dying_cpu(unsigned int cpu)
 {
         raw_spin_lock(&kvm_count_lock);
         if (kvm_usage_count)
                 hardware_disable_nolock(NULL);
         raw_spin_unlock(&kvm_count_lock);
         return 0;
 }
 
 static void hardware_disable_all_nolock(void)
 {
         BUG_ON(!kvm_usage_count);
 
         kvm_usage_count--;
         if (!kvm_usage_count)
                 on_each_cpu(hardware_disable_nolock, NULL, 1);
 }
 
 static void hardware_disable_all(void)
 {
         raw_spin_lock(&kvm_count_lock);
         hardware_disable_all_nolock();
         raw_spin_unlock(&kvm_count_lock);
 }
 
 static int hardware_enable_all(void)
 {
         int r = 0;
 
         raw_spin_lock(&kvm_count_lock);
 
         kvm_usage_count++;
         if (kvm_usage_count == 1) {
                 atomic_set(&hardware_enable_failed, 0);
                 on_each_cpu(hardware_enable_nolock, NULL, 1);
 
                 if (atomic_read(&hardware_enable_failed)) {
                         hardware_disable_all_nolock();
                         r = -EBUSY;
                 }
         }
 
         raw_spin_unlock(&kvm_count_lock);
 
         return r;
 }
 
 static int kvm_reboot(struct notifier_block *notifier, unsigned long val,
                       void *v)
 {
         /*
          * Some (well, at least mine) BIOSes hang on reboot if
          * in vmx root mode.
          *
          * And Intel TXT required VMX off for all cpu when system shutdown.
          */
         pr_info("kvm: exiting hardware virtualization\n");
         kvm_rebooting = true;
         on_each_cpu(hardware_disable_nolock, NULL, 1);
         return NOTIFY_OK;
 }
 
 static struct notifier_block kvm_reboot_notifier = {
         .notifier_call = kvm_reboot,
         .priority = 0,
 };
 
 static void kvm_io_bus_destroy(struct kvm_io_bus *bus)
 {
         int i;
 
         for (i = 0; i < bus->dev_count; i++) {
                 struct kvm_io_device *pos = bus->range[i].dev;
 
                 kvm_iodevice_destructor(pos);
         }
         kfree(bus);
 }
 
 static inline int kvm_io_bus_cmp(const struct kvm_io_range *r1,
                                  const struct kvm_io_range *r2)
 {
         gpa_t addr1 = r1->addr;
         gpa_t addr2 = r2->addr;
 
         if (addr1 < addr2)
                 return -1;
 
         /* If r2->len == 0, match the exact address.  If r2->len != 0,
          * accept any overlapping write.  Any order is acceptable for
          * overlapping ranges, because kvm_io_bus_get_first_dev ensures
          * we process all of them.
          */
         if (r2->len) {
                 addr1 += r1->len;
                 addr2 += r2->len;
         }
 
         if (addr1 > addr2)
                 return 1;
 
         return 0;
 }
 
 static int kvm_io_bus_sort_cmp(const void *p1, const void *p2)
 {
         return kvm_io_bus_cmp(p1, p2);
 }
 
 static int kvm_io_bus_get_first_dev(struct kvm_io_bus *bus,
                              gpa_t addr, int len)
 {
         struct kvm_io_range *range, key;
         int off;
 
         key = (struct kvm_io_range) {
                 .addr = addr,
                 .len = len,
         };
 
         range = bsearch(&key, bus->range, bus->dev_count,
                         sizeof(struct kvm_io_range), kvm_io_bus_sort_cmp);
         if (range == NULL)
                 return -ENOENT;
 
         off = range - bus->range;
 
         while (off > 0 && kvm_io_bus_cmp(&key, &bus->range[off-1]) == 0)
                 off--;
 
         return off;
 }
 
 static int __kvm_io_bus_write(struct kvm_vcpu *vcpu, struct kvm_io_bus *bus,
                               struct kvm_io_range *range, const void *val)
 {
         int idx;
 
         idx = kvm_io_bus_get_first_dev(bus, range->addr, range->len);
         if (idx < 0)
                 return -EOPNOTSUPP;
 
         while (idx < bus->dev_count &&
                 kvm_io_bus_cmp(range, &bus->range[idx]) == 0) {
                 if (!kvm_iodevice_write(vcpu, bus->range[idx].dev, range->addr,
                                         range->len, val))
                         return idx;
                 idx++;
         }
 
         return -EOPNOTSUPP;
 }
 
 /* kvm_io_bus_write - called under kvm->slots_lock */
 int kvm_io_bus_write(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr,
                      int len, const void *val)
 {
         struct kvm_io_bus *bus;
         struct kvm_io_range range;
         int r;
 
         range = (struct kvm_io_range) {
                 .addr = addr,
                 .len = len,
         };
 
         bus = srcu_dereference(vcpu->kvm->buses[bus_idx], &vcpu->kvm->srcu);
         if (!bus)
                 return -ENOMEM;
         r = __kvm_io_bus_write(vcpu, bus, &range, val);
         return r < 0 ? r : 0;
 }
 
 /* kvm_io_bus_write_cookie - called under kvm->slots_lock */
 int kvm_io_bus_write_cookie(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx,
                             gpa_t addr, int len, const void *val, long cookie)
 {
         struct kvm_io_bus *bus;
         struct kvm_io_range range;
 
         range = (struct kvm_io_range) {
                 .addr = addr,
                 .len = len,
         };
 
         bus = srcu_dereference(vcpu->kvm->buses[bus_idx], &vcpu->kvm->srcu);
         if (!bus)
                 return -ENOMEM;
 
         /* First try the device referenced by cookie. */
         if ((cookie >= 0) && (cookie < bus->dev_count) &&
             (kvm_io_bus_cmp(&range, &bus->range[cookie]) == 0))
                 if (!kvm_iodevice_write(vcpu, bus->range[cookie].dev, addr, len,
                                         val))
                         return cookie;
 
         /*
          * cookie contained garbage; fall back to search and return the
          * correct cookie value.
          */
         return __kvm_io_bus_write(vcpu, bus, &range, val);
 }
 
 static int __kvm_io_bus_read(struct kvm_vcpu *vcpu, struct kvm_io_bus *bus,
                              struct kvm_io_range *range, void *val)
 {
         int idx;
 
         idx = kvm_io_bus_get_first_dev(bus, range->addr, range->len);
         if (idx < 0)
                 return -EOPNOTSUPP;
 
         while (idx < bus->dev_count &&
                 kvm_io_bus_cmp(range, &bus->range[idx]) == 0) {
                 if (!kvm_iodevice_read(vcpu, bus->range[idx].dev, range->addr,
                                        range->len, val))
                         return idx;
                 idx++;
         }
 
         return -EOPNOTSUPP;
 }
 EXPORT_SYMBOL_GPL(kvm_io_bus_write);
 
 /* kvm_io_bus_read - called under kvm->slots_lock */
 int kvm_io_bus_read(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr,
                     int len, void *val)
 {
         struct kvm_io_bus *bus;
         struct kvm_io_range range;
         int r;
 
         range = (struct kvm_io_range) {
                 .addr = addr,
                 .len = len,
         };
 
         bus = srcu_dereference(vcpu->kvm->buses[bus_idx], &vcpu->kvm->srcu);
         if (!bus)
                 return -ENOMEM;
         r = __kvm_io_bus_read(vcpu, bus, &range, val);
         return r < 0 ? r : 0;
 }
 
 
 /* Caller must hold slots_lock. */
 int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
                             int len, struct kvm_io_device *dev)
 {
         int i;
         struct kvm_io_bus *new_bus, *bus;
         struct kvm_io_range range;
 
         bus = kvm_get_bus(kvm, bus_idx);
         if (!bus)
                 return -ENOMEM;
 
         /* exclude ioeventfd which is limited by maximum fd */
         if (bus->dev_count - bus->ioeventfd_count > NR_IOBUS_DEVS - 1)
                 return -ENOSPC;
 
         new_bus = kmalloc(sizeof(*bus) + ((bus->dev_count + 1) *
                           sizeof(struct kvm_io_range)), GFP_KERNEL);
         if (!new_bus)
                 return -ENOMEM;
 
         range = (struct kvm_io_range) {
                 .addr = addr,
                 .len = len,
                 .dev = dev,
         };
 
         for (i = 0; i < bus->dev_count; i++)
                 if (kvm_io_bus_cmp(&bus->range[i], &range) > 0)
                         break;
 
         memcpy(new_bus, bus, sizeof(*bus) + i * sizeof(struct kvm_io_range));
         new_bus->dev_count++;
         new_bus->range[i] = range;
         memcpy(new_bus->range + i + 1, bus->range + i,
                 (bus->dev_count - i) * sizeof(struct kvm_io_range));
         rcu_assign_pointer(kvm->buses[bus_idx], new_bus);
         synchronize_srcu_expedited(&kvm->srcu);
         kfree(bus);
 
         return 0;
 }
 
 /* Caller must hold slots_lock. */
 void kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
                                struct kvm_io_device *dev)
 {
         int i;
         struct kvm_io_bus *new_bus, *bus;
 
         bus = kvm_get_bus(kvm, bus_idx);
         if (!bus)
                 return;
 
         for (i = 0; i < bus->dev_count; i++)
                 if (bus->range[i].dev == dev) {
                         break;
                 }
 
         if (i == bus->dev_count)
                 return;
 
         new_bus = kmalloc(sizeof(*bus) + ((bus->dev_count - 1) *
                           sizeof(struct kvm_io_range)), GFP_KERNEL);
         if (!new_bus)  {
                 pr_err("kvm: failed to shrink bus, removing it completely\n");
                 goto broken;
         }
 
         memcpy(new_bus, bus, sizeof(*bus) + i * sizeof(struct kvm_io_range));
         new_bus->dev_count--;
         memcpy(new_bus->range + i, bus->range + i + 1,
                (new_bus->dev_count - i) * sizeof(struct kvm_io_range));
 
 broken:
         rcu_assign_pointer(kvm->buses[bus_idx], new_bus);
         synchronize_srcu_expedited(&kvm->srcu);
         kfree(bus);
         return;
 }
 
 struct kvm_io_device *kvm_io_bus_get_dev(struct kvm *kvm, enum kvm_bus bus_idx,
                                          gpa_t addr)
 {
         struct kvm_io_bus *bus;
         int dev_idx, srcu_idx;
         struct kvm_io_device *iodev = NULL;
 
         srcu_idx = srcu_read_lock(&kvm->srcu);
 
         bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);
         if (!bus)
                 goto out_unlock;
 
         dev_idx = kvm_io_bus_get_first_dev(bus, addr, 1);
         if (dev_idx < 0)
                 goto out_unlock;
 
         iodev = bus->range[dev_idx].dev;
 
 out_unlock:
         srcu_read_unlock(&kvm->srcu, srcu_idx);
 
         return iodev;
 }
 EXPORT_SYMBOL_GPL(kvm_io_bus_get_dev);
 
 static int kvm_debugfs_open(struct inode *inode, struct file *file,
                            int (*get)(void *, u64 *), int (*set)(void *, u64),
                            const char *fmt)
 {
         struct kvm_stat_data *stat_data = (struct kvm_stat_data *)
                                           inode->i_private;
 
         /* The debugfs files are a reference to the kvm struct which
          * is still valid when kvm_destroy_vm is called.
          * To avoid the race between open and the removal of the debugfs
          * directory we test against the users count.
          */
         if (!refcount_inc_not_zero(&stat_data->kvm->users_count))
                 return -ENOENT;
 
         if (simple_attr_open(inode, file, get, set, fmt)) {
                 kvm_put_kvm(stat_data->kvm);
                 return -ENOMEM;
         }
 
         return 0;
 }
 
 static int kvm_debugfs_release(struct inode *inode, struct file *file)
 {
         struct kvm_stat_data *stat_data = (struct kvm_stat_data *)
                                           inode->i_private;
 
         simple_attr_release(inode, file);
         kvm_put_kvm(stat_data->kvm);
 
         return 0;
 }
 
 static int vm_stat_get_per_vm(void *data, u64 *val)
 {
         struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
 
         *val = *(ulong *)((void *)stat_data->kvm + stat_data->offset);
 
         return 0;
 }
 
 static int vm_stat_clear_per_vm(void *data, u64 val)
 {
         struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
 
         if (val)
                 return -EINVAL;
 
         *(ulong *)((void *)stat_data->kvm + stat_data->offset) = 0;
 
         return 0;
 }
 
 static int vm_stat_get_per_vm_open(struct inode *inode, struct file *file)
 {
         __simple_attr_check_format("%llu\n", 0ull);
         return kvm_debugfs_open(inode, file, vm_stat_get_per_vm,
                                 vm_stat_clear_per_vm, "%llu\n");
 }
 
 static const struct file_operations vm_stat_get_per_vm_fops = {
         .owner   = THIS_MODULE,
         .open    = vm_stat_get_per_vm_open,
         .release = kvm_debugfs_release,
         .read    = simple_attr_read,
         .write   = simple_attr_write,
         .llseek  = no_llseek,
 };
 
 static int vcpu_stat_get_per_vm(void *data, u64 *val)
 {
         int i;
         struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
         struct kvm_vcpu *vcpu;
 
         *val = 0;
 
         kvm_for_each_vcpu(i, vcpu, stat_data->kvm)
                 *val += *(u64 *)((void *)vcpu + stat_data->offset);
 
         return 0;
 }
 
 static int vcpu_stat_clear_per_vm(void *data, u64 val)
 {
         int i;
         struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
         struct kvm_vcpu *vcpu;
 
         if (val)
                 return -EINVAL;
 
         kvm_for_each_vcpu(i, vcpu, stat_data->kvm)
                 *(u64 *)((void *)vcpu + stat_data->offset) = 0;
 
         return 0;
 }
 
 static int vcpu_stat_get_per_vm_open(struct inode *inode, struct file *file)
 {
         __simple_attr_check_format("%llu\n", 0ull);
         return kvm_debugfs_open(inode, file, vcpu_stat_get_per_vm,
                                  vcpu_stat_clear_per_vm, "%llu\n");
 }
 
 static const struct file_operations vcpu_stat_get_per_vm_fops = {
         .owner   = THIS_MODULE,
         .open    = vcpu_stat_get_per_vm_open,
         .release = kvm_debugfs_release,
         .read    = simple_attr_read,
         .write   = simple_attr_write,
         .llseek  = no_llseek,
 };
 
 static const struct file_operations *stat_fops_per_vm[] = {
         [KVM_STAT_VCPU] = &vcpu_stat_get_per_vm_fops,
         [KVM_STAT_VM]   = &vm_stat_get_per_vm_fops,
 };
 
 static int vm_stat_get(void *_offset, u64 *val)
 {
         unsigned offset = (long)_offset;
         struct kvm *kvm;
         struct kvm_stat_data stat_tmp = {.offset = offset};
         u64 tmp_val;
 
         *val = 0;
         spin_lock(&kvm_lock);
         list_for_each_entry(kvm, &vm_list, vm_list) {
                 stat_tmp.kvm = kvm;
                 vm_stat_get_per_vm((void *)&stat_tmp, &tmp_val);
                 *val += tmp_val;
         }
         spin_unlock(&kvm_lock);
         return 0;
 }
 
 static int vm_stat_clear(void *_offset, u64 val)
 {
         unsigned offset = (long)_offset;
         struct kvm *kvm;
         struct kvm_stat_data stat_tmp = {.offset = offset};
 
         if (val)
                 return -EINVAL;
 
         spin_lock(&kvm_lock);
         list_for_each_entry(kvm, &vm_list, vm_list) {
                 stat_tmp.kvm = kvm;
                 vm_stat_clear_per_vm((void *)&stat_tmp, 0);
         }
         spin_unlock(&kvm_lock);
 
         return 0;
 }
 
 DEFINE_SIMPLE_ATTRIBUTE(vm_stat_fops, vm_stat_get, vm_stat_clear, "%llu\n");
 
 static int vcpu_stat_get(void *_offset, u64 *val)
 {
         unsigned offset = (long)_offset;
         struct kvm *kvm;
         struct kvm_stat_data stat_tmp = {.offset = offset};
         u64 tmp_val;
 
         *val = 0;
         spin_lock(&kvm_lock);
         list_for_each_entry(kvm, &vm_list, vm_list) {
                 stat_tmp.kvm = kvm;
                 vcpu_stat_get_per_vm((void *)&stat_tmp, &tmp_val);
                 *val += tmp_val;
         }
         spin_unlock(&kvm_lock);
         return 0;
 }
 
 static int vcpu_stat_clear(void *_offset, u64 val)
 {
         unsigned offset = (long)_offset;
         struct kvm *kvm;
         struct kvm_stat_data stat_tmp = {.offset = offset};
 
         if (val)
                 return -EINVAL;
 
         spin_lock(&kvm_lock);
         list_for_each_entry(kvm, &vm_list, vm_list) {
                 stat_tmp.kvm = kvm;
                 vcpu_stat_clear_per_vm((void *)&stat_tmp, 0);
         }
         spin_unlock(&kvm_lock);
 
         return 0;
 }
 
 DEFINE_SIMPLE_ATTRIBUTE(vcpu_stat_fops, vcpu_stat_get, vcpu_stat_clear,
                         "%llu\n");
 
 static const struct file_operations *stat_fops[] = {
         [KVM_STAT_VCPU] = &vcpu_stat_fops,
         [KVM_STAT_VM]   = &vm_stat_fops,
 };
 
 static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm)
 {
         struct kobj_uevent_env *env;
         unsigned long long created, active;
 
         if (!kvm_dev.this_device || !kvm)
                 return;
 
         spin_lock(&kvm_lock);
         if (type == KVM_EVENT_CREATE_VM) {
                 kvm_createvm_count++;
                 kvm_active_vms++;
         } else if (type == KVM_EVENT_DESTROY_VM) {
                 kvm_active_vms--;
         }
         created = kvm_createvm_count;
         active = kvm_active_vms;
         spin_unlock(&kvm_lock);
 
         env = kzalloc(sizeof(*env), GFP_KERNEL);
         if (!env)
                 return;
 
         add_uevent_var(env, "CREATED=%llu", created);
         add_uevent_var(env, "COUNT=%llu", active);
 
         if (type == KVM_EVENT_CREATE_VM) {
                 add_uevent_var(env, "EVENT=create");
                 kvm->userspace_pid = task_pid_nr(current);
         } else if (type == KVM_EVENT_DESTROY_VM) {
                 add_uevent_var(env, "EVENT=destroy");
         }
         add_uevent_var(env, "PID=%d", kvm->userspace_pid);
 
         if (!IS_ERR_OR_NULL(kvm->debugfs_dentry)) {
                 char *tmp, *p = kmalloc(PATH_MAX, GFP_KERNEL);
 
                 if (p) {
                         tmp = dentry_path_raw(kvm->debugfs_dentry, p, PATH_MAX);
                         if (!IS_ERR(tmp))
                                 add_uevent_var(env, "STATS_PATH=%s", tmp);
                         kfree(p);
                 }
         }
         /* no need for checks, since we are adding at most only 5 keys */
         env->envp[env->envp_idx++] = NULL;
         kobject_uevent_env(&kvm_dev.this_device->kobj, KOBJ_CHANGE, env->envp);
         kfree(env);
 }
 
 static void kvm_init_debug(void)
 {
         struct kvm_stats_debugfs_item *p;
 
         kvm_debugfs_dir = debugfs_create_dir("kvm", NULL);
 
         kvm_debugfs_num_entries = 0;
         for (p = debugfs_entries; p->name; ++p, kvm_debugfs_num_entries++) {
                 debugfs_create_file(p->name, 0644, kvm_debugfs_dir,
                                     (void *)(long)p->offset,
                                     stat_fops[p->kind]);
         }
 }
 
 static int kvm_suspend(void)
 {
         if (kvm_usage_count)
                 hardware_disable_nolock(NULL);
         return 0;
 }
 
 static void kvm_resume(void)
 {
         if (kvm_usage_count) {
                 WARN_ON(raw_spin_is_locked(&kvm_count_lock));
                 hardware_enable_nolock(NULL);
         }
 }
 
 static struct syscore_ops kvm_syscore_ops = {
         .suspend = kvm_suspend,
         .resume = kvm_resume,
 };
 
 static inline
 struct kvm_vcpu *preempt_notifier_to_vcpu(struct preempt_notifier *pn)
 {
         return container_of(pn, struct kvm_vcpu, preempt_notifier);
 }
 
 static void kvm_sched_in(struct preempt_notifier *pn, int cpu)
 {
         struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);
 
         if (vcpu->preempted)
                 vcpu->preempted = false;
 
         kvm_arch_sched_in(vcpu, cpu);
 
         kvm_arch_vcpu_load(vcpu, cpu);
 }
 
 static void kvm_sched_out(struct preempt_notifier *pn,
                           struct task_struct *next)
 {
         struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);
 
         if (current->state == TASK_RUNNING)
                 vcpu->preempted = true;
         kvm_arch_vcpu_put(vcpu);
 }
 
 int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
                   struct module *module)
 {
         int r;
         int cpu;
 
         r = kvm_arch_init(opaque);
         if (r)
                 goto out_fail;
 
         /*
          * kvm_arch_init makes sure there's at most one caller
          * for architectures that support multiple implementations,
          * like intel and amd on x86.
          * kvm_arch_init must be called before kvm_irqfd_init to avoid creating
          * conflicts in case kvm is already setup for another implementation.
          */
         r = kvm_irqfd_init();
         if (r)
                 goto out_irqfd;
 
         if (!zalloc_cpumask_var(&cpus_hardware_enabled, GFP_KERNEL)) {
                 r = -ENOMEM;
                 goto out_free_0;
         }
 
         r = kvm_arch_hardware_setup();
         if (r < 0)
                 goto out_free_0a;
 
         for_each_online_cpu(cpu) {
                 smp_call_function_single(cpu,
                                 kvm_arch_check_processor_compat,
                                 &r, 1);
                 if (r < 0)
                         goto out_free_1;
         }
 
         r = cpuhp_setup_state_nocalls(CPUHP_AP_KVM_STARTING, "kvm/cpu:starting",
                                       kvm_starting_cpu, kvm_dying_cpu);
         if (r)
                 goto out_free_2;
         register_reboot_notifier(&kvm_reboot_notifier);
 
         /* A kmem cache lets us meet the alignment requirements of fx_save. */
         if (!vcpu_align)
                 vcpu_align = __alignof__(struct kvm_vcpu);
         kvm_vcpu_cache =
                 kmem_cache_create_usercopy("kvm_vcpu", vcpu_size, vcpu_align,
                                            SLAB_ACCOUNT,
                                            offsetof(struct kvm_vcpu, arch),
                                            sizeof_field(struct kvm_vcpu, arch),
                                            NULL);
         if (!kvm_vcpu_cache) {
                 r = -ENOMEM;
                 goto out_free_3;
         }
 
         r = kvm_async_pf_init();
         if (r)
                 goto out_free;
 
         kvm_chardev_ops.owner = module;
         kvm_vm_fops.owner = module;
         kvm_vcpu_fops.owner = module;
 
         r = misc_register(&kvm_dev);
         if (r) {
                 pr_err("kvm: misc device register failed\n");
                 goto out_unreg;
         }
 
         register_syscore_ops(&kvm_syscore_ops);
 
         kvm_preempt_ops.sched_in = kvm_sched_in;
         kvm_preempt_ops.sched_out = kvm_sched_out;
 
         kvm_init_debug();
 
         r = kvm_vfio_ops_init();
         WARN_ON(r);
 
         return 0;
 
 out_unreg:
         kvm_async_pf_deinit();
 out_free:
         kmem_cache_destroy(kvm_vcpu_cache);
 out_free_3:
         unregister_reboot_notifier(&kvm_reboot_notifier);
         cpuhp_remove_state_nocalls(CPUHP_AP_KVM_STARTING);
 out_free_2:
 out_free_1:
         kvm_arch_hardware_unsetup();
 out_free_0a:
         free_cpumask_var(cpus_hardware_enabled);
 out_free_0:
         kvm_irqfd_exit();
 out_irqfd:
         kvm_arch_exit();
 out_fail:
         return r;
 }
 EXPORT_SYMBOL_GPL(kvm_init);
 
 void kvm_exit(void)
 {
         debugfs_remove_recursive(kvm_debugfs_dir);
         misc_deregister(&kvm_dev);
         kmem_cache_destroy(kvm_vcpu_cache);
         kvm_async_pf_deinit();
         unregister_syscore_ops(&kvm_syscore_ops);
         unregister_reboot_notifier(&kvm_reboot_notifier);
         cpuhp_remove_state_nocalls(CPUHP_AP_KVM_STARTING);
         on_each_cpu(hardware_disable_nolock, NULL, 1);
         kvm_arch_hardware_unsetup();
         kvm_arch_exit();
         kvm_irqfd_exit();
         free_cpumask_var(cpus_hardware_enabled);
         kvm_vfio_ops_exit();
 }
 EXPORT_SYMBOL_GPL(kvm_exit);