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

   // SPDX-License-Identifier: GPL-2.0-only
   /*
    * 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>
   */
  
  #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 <linux/io.h>
  #include <linux/lockdep.h>
  #include <linux/kthread.h>
  #include <linux/suspend.h>
  
  #include <asm/processor.h>
  #include <asm/ioctl.h>
  #include <linux/uaccess.h>
  
  #include "coalesced_mmio.h"
  #include "async_pf.h"
  #include "mmu_lock.h"
  #include "vfio.h"
  
  #define CREATE_TRACE_POINTS
  #include <trace/events/kvm.h>
  
  #include <linux/kvm_dirty_ring.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);
  
  /* The start value to grow halt_poll_ns from */
  unsigned int halt_poll_ns_grow_start = 10000; /* 10us */
  module_param(halt_poll_ns_grow_start, uint, 0644);
  EXPORT_SYMBOL_GPL(halt_poll_ns_grow_start);
  
  /* 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_MUTEX(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;
 
 static struct kmem_cache *kvm_vcpu_cache;
 
 static __read_mostly struct preempt_ops kvm_preempt_ops;
 static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_running_vcpu);
 
 struct dentry *kvm_debugfs_dir;
 EXPORT_SYMBOL_GPL(kvm_debugfs_dir);
 
 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
 /*
  * For architectures that don't implement a compat infrastructure,
  * adopt a double line of defense:
  * - Prevent a compat task from opening /dev/kvm
  * - If the open has been done by a 64bit task, and the KVM fd
  *   passed to a compat task, let the ioctls fail.
  */
 static long kvm_no_compat_ioctl(struct file *file, unsigned int ioctl,
                                 unsigned long arg) { return -EINVAL; }
 
 static int kvm_no_compat_open(struct inode *inode, struct file *file)
 {
         return is_compat_task() ? -ENODEV : 0;
 }
 #define KVM_COMPAT(c)   .compat_ioctl   = kvm_no_compat_ioctl,  \
                         .open           = kvm_no_compat_open
 #endif
 static int hardware_enable_all(void);
 static void hardware_disable_all(void);
 
 static void kvm_io_bus_destroy(struct kvm_io_bus *bus);
 
 __visible bool kvm_rebooting;
 EXPORT_SYMBOL_GPL(kvm_rebooting);
 
 #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 void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
                                                    unsigned long start, unsigned long end)
 {
 }
 
 bool kvm_is_zone_device_pfn(kvm_pfn_t pfn)
 {
         /*
          * The metadata used by is_zone_device_page() to determine whether or
          * not a page is ZONE_DEVICE is guaranteed to be valid if and only if
          * the device has been pinned, e.g. by get_user_pages().  WARN if the
          * page_count() is zero to help detect bad usage of this helper.
          */
         if (!pfn_valid(pfn) || WARN_ON_ONCE(!page_count(pfn_to_page(pfn))))
                 return false;
 
         return is_zone_device_page(pfn_to_page(pfn));
 }
 
 bool kvm_is_reserved_pfn(kvm_pfn_t pfn)
 {
         /*
          * ZONE_DEVICE pages currently set PG_reserved, but from a refcounting
          * perspective they are "normal" pages, albeit with slightly different
          * usage rules.
          */
         if (pfn_valid(pfn))
                 return PageReserved(pfn_to_page(pfn)) &&
                        !is_zero_pfn(pfn) &&
                        !kvm_is_zone_device_pfn(pfn);
 
         return true;
 }
 
 bool kvm_is_transparent_hugepage(kvm_pfn_t pfn)
 {
         struct page *page = pfn_to_page(pfn);
 
         if (!PageTransCompoundMap(page))
                 return false;
 
         return is_transparent_hugepage(compound_head(page));
 }
 
 /*
  * Switches to specified vcpu, until a matching vcpu_put()
  */
 void vcpu_load(struct kvm_vcpu *vcpu)
 {
         int cpu = get_cpu();
 
         __this_cpu_write(kvm_running_vcpu, vcpu);
         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);
         __this_cpu_write(kvm_running_vcpu, NULL);
         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,
                                  struct kvm_vcpu *except,
                                  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)) ||
                     vcpu == except)
                         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_except(struct kvm *kvm, unsigned int req,
                                       struct kvm_vcpu *except)
 {
         cpumask_var_t cpus;
         bool called;
 
         zalloc_cpumask_var(&cpus, GFP_ATOMIC);
 
         called = kvm_make_vcpus_request_mask(kvm, req, except, NULL, cpus);
 
         free_cpumask_var(cpus);
         return called;
 }
 
 bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
 {
         return kvm_make_all_cpus_request_except(kvm, req, NULL);
 }
 EXPORT_SYMBOL_GPL(kvm_make_all_cpus_request);
 
 #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.generic.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);
 }
 
 #ifdef KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE
 static inline void *mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache *mc,
                                                gfp_t gfp_flags)
 {
         gfp_flags |= mc->gfp_zero;
 
         if (mc->kmem_cache)
                 return kmem_cache_alloc(mc->kmem_cache, gfp_flags);
         else
                 return (void *)__get_free_page(gfp_flags);
 }
 
 int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min)
 {
         void *obj;
 
         if (mc->nobjs >= min)
                 return 0;
         while (mc->nobjs < ARRAY_SIZE(mc->objects)) {
                 obj = mmu_memory_cache_alloc_obj(mc, GFP_KERNEL_ACCOUNT);
                 if (!obj)
                         return mc->nobjs >= min ? 0 : -ENOMEM;
                 mc->objects[mc->nobjs++] = obj;
         }
         return 0;
 }
 
 int kvm_mmu_memory_cache_nr_free_objects(struct kvm_mmu_memory_cache *mc)
 {
         return mc->nobjs;
 }
 
 void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
 {
         while (mc->nobjs) {
                 if (mc->kmem_cache)
                         kmem_cache_free(mc->kmem_cache, mc->objects[--mc->nobjs]);
                 else
                         free_page((unsigned long)mc->objects[--mc->nobjs]);
         }
 }
 
 void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
 {
         void *p;
 
         if (WARN_ON(!mc->nobjs))
                 p = mmu_memory_cache_alloc_obj(mc, GFP_ATOMIC | __GFP_ACCOUNT);
         else
                 p = mc->objects[--mc->nobjs];
         BUG_ON(!p);
         return p;
 }
 #endif
 
 static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
 {
         mutex_init(&vcpu->mutex);
         vcpu->cpu = -1;
         vcpu->kvm = kvm;
         vcpu->vcpu_id = id;
         vcpu->pid = NULL;
         rcuwait_init(&vcpu->wait);
         kvm_async_pf_vcpu_init(vcpu);
 
         vcpu->pre_pcpu = -1;
         INIT_LIST_HEAD(&vcpu->blocked_vcpu_list);
 
         kvm_vcpu_set_in_spin_loop(vcpu, false);
         kvm_vcpu_set_dy_eligible(vcpu, false);
         vcpu->preempted = false;
         vcpu->ready = false;
         preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops);
 }
 
 void kvm_vcpu_destroy(struct kvm_vcpu *vcpu)
 {
         kvm_dirty_ring_free(&vcpu->dirty_ring);
         kvm_arch_vcpu_destroy(vcpu);
 
         /*
          * No need for rcu_read_lock as VCPU_RUN is the only place that changes
          * the vcpu->pid pointer, and at destruction time all file descriptors
          * are already gone.
          */
         put_pid(rcu_dereference_protected(vcpu->pid, 1));
 
         free_page((unsigned long)vcpu->run);
         kmem_cache_free(kvm_vcpu_cache, vcpu);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_destroy);
 
 #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_invalidate_range(struct mmu_notifier *mn,
                                               struct mm_struct *mm,
                                               unsigned long start, unsigned long end)
 {
         struct kvm *kvm = mmu_notifier_to_kvm(mn);
         int idx;
 
         idx = srcu_read_lock(&kvm->srcu);
         kvm_arch_mmu_notifier_invalidate_range(kvm, start, end);
         srcu_read_unlock(&kvm->srcu, idx);
 }
 
 typedef bool (*hva_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range);
 
 typedef void (*on_lock_fn_t)(struct kvm *kvm, unsigned long start,
                              unsigned long end);
 
 struct kvm_hva_range {
         unsigned long start;
         unsigned long end;
         pte_t pte;
         hva_handler_t handler;
         on_lock_fn_t on_lock;
         bool flush_on_ret;
         bool may_block;
 };
 
 /*
  * Use a dedicated stub instead of NULL to indicate that there is no callback
  * function/handler.  The compiler technically can't guarantee that a real
  * function will have a non-zero address, and so it will generate code to
  * check for !NULL, whereas comparing against a stub will be elided at compile
  * time (unless the compiler is getting long in the tooth, e.g. gcc 4.9).
  */
 static void kvm_null_fn(void)
 {
 
 }
 #define IS_KVM_NULL_FN(fn) ((fn) == (void *)kvm_null_fn)
 
 static __always_inline int __kvm_handle_hva_range(struct kvm *kvm,
                                                   const struct kvm_hva_range *range)
 {
         bool ret = false, locked = false;
         struct kvm_gfn_range gfn_range;
         struct kvm_memory_slot *slot;
         struct kvm_memslots *slots;
         int i, idx;
 
         /* A null handler is allowed if and only if on_lock() is provided. */
         if (WARN_ON_ONCE(IS_KVM_NULL_FN(range->on_lock) &&
                          IS_KVM_NULL_FN(range->handler)))
                 return 0;
 
         idx = srcu_read_lock(&kvm->srcu);
 
         /* The on_lock() path does not yet support lock elision. */
         if (!IS_KVM_NULL_FN(range->on_lock)) {
                 locked = true;
                 KVM_MMU_LOCK(kvm);
 
                 range->on_lock(kvm, range->start, range->end);
 
                 if (IS_KVM_NULL_FN(range->handler))
                         goto out_unlock;
         }
 
         for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
                 slots = __kvm_memslots(kvm, i);
                 kvm_for_each_memslot(slot, slots) {
                         unsigned long hva_start, hva_end;
 
                         hva_start = max(range->start, slot->userspace_addr);
                         hva_end = min(range->end, slot->userspace_addr +
                                                   (slot->npages << PAGE_SHIFT));
                         if (hva_start >= hva_end)
                                 continue;
 
                         /*
                          * To optimize for the likely case where the address
                          * range is covered by zero or one memslots, don't
                          * bother making these conditional (to avoid writes on
                          * the second or later invocation of the handler).
                          */
                         gfn_range.pte = range->pte;
                         gfn_range.may_block = range->may_block;
 
                         /*
                          * {gfn(page) | page intersects with [hva_start, hva_end)} =
                          * {gfn_start, gfn_start+1, ..., gfn_end-1}.
                          */
                         gfn_range.start = hva_to_gfn_memslot(hva_start, slot);
                         gfn_range.end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, slot);
                         gfn_range.slot = slot;
 
                         if (!locked) {
                                 locked = true;
                                 KVM_MMU_LOCK(kvm);
                         }
                         ret |= range->handler(kvm, &gfn_range);
                 }
         }
 
         if (range->flush_on_ret && (ret || kvm->tlbs_dirty))
                 kvm_flush_remote_tlbs(kvm);
 
 out_unlock:
         if (locked)
                 KVM_MMU_UNLOCK(kvm);
 
         srcu_read_unlock(&kvm->srcu, idx);
 
         /* The notifiers are averse to booleans. :-( */
         return (int)ret;
 }
 
 static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn,
                                                 unsigned long start,
                                                 unsigned long end,
                                                 pte_t pte,
                                                 hva_handler_t handler)
 {
         struct kvm *kvm = mmu_notifier_to_kvm(mn);
         const struct kvm_hva_range range = {
                 .start          = start,
                 .end            = end,
                 .pte            = pte,
                 .handler        = handler,
                 .on_lock        = (void *)kvm_null_fn,
                 .flush_on_ret   = true,
                 .may_block      = false,
         };
 
         return __kvm_handle_hva_range(kvm, &range);
 }
 
 static __always_inline int kvm_handle_hva_range_no_flush(struct mmu_notifier *mn,
                                                          unsigned long start,
                                                          unsigned long end,
                                                          hva_handler_t handler)
 {
         struct kvm *kvm = mmu_notifier_to_kvm(mn);
         const struct kvm_hva_range range = {
                 .start          = start,
                 .end            = end,
                 .pte            = __pte(0),
                 .handler        = handler,
                 .on_lock        = (void *)kvm_null_fn,
                 .flush_on_ret   = false,
                 .may_block      = false,
         };
 
         return __kvm_handle_hva_range(kvm, &range);
 }
 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);
 
         trace_kvm_set_spte_hva(address);
 
         /*
          * .change_pte() must be surrounded by .invalidate_range_{start,end}(),
          * and so always runs with an elevated notifier count.  This obviates
          * the need to bump the sequence count.
          */
         WARN_ON_ONCE(!kvm->mmu_notifier_count);
 
         kvm_handle_hva_range(mn, address, address + 1, pte, kvm_set_spte_gfn);
 }
 
 static void kvm_inc_notifier_count(struct kvm *kvm, unsigned long start,
                                    unsigned long end)
 {
         /*
          * 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++;
         if (likely(kvm->mmu_notifier_count == 1)) {
                 kvm->mmu_notifier_range_start = start;
                 kvm->mmu_notifier_range_end = end;
         } else {
                 /*
                  * Fully tracking multiple concurrent ranges has dimishing
                  * returns. Keep things simple and just find the minimal range
                  * which includes the current and new ranges. As there won't be
                  * enough information to subtract a range after its invalidate
                  * completes, any ranges invalidated concurrently will
                  * accumulate and persist until all outstanding invalidates
                  * complete.
                  */
                 kvm->mmu_notifier_range_start =
                         min(kvm->mmu_notifier_range_start, start);
                 kvm->mmu_notifier_range_end =
                         max(kvm->mmu_notifier_range_end, end);
         }
 }
 
 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);
         const struct kvm_hva_range hva_range = {
                 .start          = range->start,
                 .end            = range->end,
                 .pte            = __pte(0),
                 .handler        = kvm_unmap_gfn_range,
                 .on_lock        = kvm_inc_notifier_count,
                 .flush_on_ret   = true,
                 .may_block      = mmu_notifier_range_blockable(range),
         };
 
         trace_kvm_unmap_hva_range(range->start, range->end);
 
         __kvm_handle_hva_range(kvm, &hva_range);
 
         return 0;
 }
 
 static void kvm_dec_notifier_count(struct kvm *kvm, unsigned long start,
                                    unsigned long end)
 {
         /*
          * 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--;
 }
 
 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);
         const struct kvm_hva_range hva_range = {
                 .start          = range->start,
                 .end            = range->end,
                 .pte            = __pte(0),
                 .handler        = (void *)kvm_null_fn,
                 .on_lock        = kvm_dec_notifier_count,
                 .flush_on_ret   = false,
                 .may_block      = mmu_notifier_range_blockable(range),
         };
 
         __kvm_handle_hva_range(kvm, &hva_range);
 
         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)
 {
         trace_kvm_age_hva(start, end);
 
         return kvm_handle_hva_range(mn, start, end, __pte(0), kvm_age_gfn);
 }
 
 static int kvm_mmu_notifier_clear_young(struct mmu_notifier *mn,
                                         struct mm_struct *mm,
                                         unsigned long start,
                                         unsigned long end)
 {
         trace_kvm_age_hva(start, end);
 
         /*
          * 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.
          */
         return kvm_handle_hva_range_no_flush(mn, start, end, kvm_age_gfn);
 }
 
 static int kvm_mmu_notifier_test_young(struct mmu_notifier *mn,
                                        struct mm_struct *mm,
                                        unsigned long address)
 {
         trace_kvm_test_age_hva(address);
 
         return kvm_handle_hva_range_no_flush(mn, address, address + 1,
                                              kvm_test_age_gfn);
 }
 
 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       = kvm_mmu_notifier_invalidate_range,
         .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 */
 
 #ifdef CONFIG_HAVE_KVM_PM_NOTIFIER
 static int kvm_pm_notifier_call(struct notifier_block *bl,
                                 unsigned long state,
                                 void *unused)
 {
         struct kvm *kvm = container_of(bl, struct kvm, pm_notifier);
 
         return kvm_arch_pm_notifier(kvm, state);
 }
 
 static void kvm_init_pm_notifier(struct kvm *kvm)
 {
         kvm->pm_notifier.notifier_call = kvm_pm_notifier_call;
         /* Suspend KVM before we suspend ftrace, RCU, etc. */
         kvm->pm_notifier.priority = INT_MAX;
         register_pm_notifier(&kvm->pm_notifier);
 }
 
 static void kvm_destroy_pm_notifier(struct kvm *kvm)
 {
         unregister_pm_notifier(&kvm->pm_notifier);
 }
 #else /* !CONFIG_HAVE_KVM_PM_NOTIFIER */
 static void kvm_init_pm_notifier(struct kvm *kvm)
 {
 }
 
 static void kvm_destroy_pm_notifier(struct kvm *kvm)
 {
 }
 #endif /* CONFIG_HAVE_KVM_PM_NOTIFIER */
 
 static struct kvm_memslots *kvm_alloc_memslots(void)
 {
         int i;
         struct kvm_memslots *slots;
 
         slots = kvzalloc(sizeof(struct kvm_memslots), GFP_KERNEL_ACCOUNT);
         if (!slots)
                 return NULL;
 
         for (i = 0; i < KVM_MEM_SLOTS_NUM; i++)
                 slots->id_to_index[i] = -1;
 
         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;
 }
 
 static void kvm_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot)
 {
         kvm_destroy_dirty_bitmap(slot);
 
         kvm_arch_free_memslot(kvm, slot);
 
         slot->flags = 0;
         slot->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);
 
         kvfree(slots);
 }
 
 static umode_t kvm_stats_debugfs_mode(const struct _kvm_stats_desc *pdesc)
 {
         switch (pdesc->desc.flags & KVM_STATS_TYPE_MASK) {
         case KVM_STATS_TYPE_INSTANT:
                 return 0444;
         case KVM_STATS_TYPE_CUMULATIVE:
         case KVM_STATS_TYPE_PEAK:
         default:
                 return 0644;
         }
 }
 
 
 static void kvm_destroy_vm_debugfs(struct kvm *kvm)
 {
         int i;
         int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc +
                                       kvm_vcpu_stats_header.num_desc;
 
         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)
 {
         static DEFINE_MUTEX(kvm_debugfs_lock);
         struct dentry *dent;
         char dir_name[ITOA_MAX_LEN * 2];
         struct kvm_stat_data *stat_data;
         const struct _kvm_stats_desc *pdesc;
         int i;
         int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc +
                                       kvm_vcpu_stats_header.num_desc;
 
         if (!debugfs_initialized())
                 return 0;
 
         snprintf(dir_name, sizeof(dir_name), "%d-%d", task_pid_nr(current), fd);
         mutex_lock(&kvm_debugfs_lock);
         dent = debugfs_lookup(dir_name, kvm_debugfs_dir);
         if (dent) {
                 pr_warn_ratelimited("KVM: debugfs: duplicate directory %s\n", dir_name);
                 dput(dent);
                 mutex_unlock(&kvm_debugfs_lock);
                 return 0;
         }
         dent = debugfs_create_dir(dir_name, kvm_debugfs_dir);
         mutex_unlock(&kvm_debugfs_lock);
         if (IS_ERR(dent))
                 return 0;
 
         kvm->debugfs_dentry = dent;
         kvm->debugfs_stat_data = kcalloc(kvm_debugfs_num_entries,
                                          sizeof(*kvm->debugfs_stat_data),
                                          GFP_KERNEL_ACCOUNT);
         if (!kvm->debugfs_stat_data)
                 return -ENOMEM;
 
         for (i = 0; i < kvm_vm_stats_header.num_desc; ++i) {
                 pdesc = &kvm_vm_stats_desc[i];
                 stat_data = kzalloc(sizeof(*stat_data), GFP_KERNEL_ACCOUNT);
                 if (!stat_data)
                         return -ENOMEM;
 
                 stat_data->kvm = kvm;
                 stat_data->desc = pdesc;
                 stat_data->kind = KVM_STAT_VM;
                 kvm->debugfs_stat_data[i] = stat_data;
                 debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
                                     kvm->debugfs_dentry, stat_data,
                                     &stat_fops_per_vm);
         }
 
         for (i = 0; i < kvm_vcpu_stats_header.num_desc; ++i) {
                 pdesc = &kvm_vcpu_stats_desc[i];
                 stat_data = kzalloc(sizeof(*stat_data), GFP_KERNEL_ACCOUNT);
                 if (!stat_data)
                         return -ENOMEM;
 
                 stat_data->kvm = kvm;
                 stat_data->desc = pdesc;
                 stat_data->kind = KVM_STAT_VCPU;
                 kvm->debugfs_stat_data[i + kvm_vm_stats_header.num_desc] = stat_data;
                 debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
                                     kvm->debugfs_dentry, stat_data,
                                     &stat_fops_per_vm);
         }
         return 0;
 }
 
 /*
  * Called after the VM is otherwise initialized, but just before adding it to
  * the vm_list.
  */
 int __weak kvm_arch_post_init_vm(struct kvm *kvm)
 {
         return 0;
 }
 
 /*
  * Called just after removing the VM from the vm_list, but before doing any
  * other destruction.
  */
 void __weak kvm_arch_pre_destroy_vm(struct kvm *kvm)
 {
 }
 
 static struct kvm *kvm_create_vm(unsigned long type)
 {
         struct kvm *kvm = kvm_arch_alloc_vm();
         int r = -ENOMEM;
         int i;
 
         if (!kvm)
                 return ERR_PTR(-ENOMEM);
 
         KVM_MMU_LOCK_INIT(kvm);
         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);
         mutex_init(&kvm->slots_arch_lock);
         INIT_LIST_HEAD(&kvm->devices);
 
         BUILD_BUG_ON(KVM_MEM_SLOTS_NUM > SHRT_MAX);
 
         if (init_srcu_struct(&kvm->srcu))
                 goto out_err_no_srcu;
         if (init_srcu_struct(&kvm->irq_srcu))
                 goto out_err_no_irq_srcu;
 
         refcount_set(&kvm->users_count, 1);
         for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
                 struct kvm_memslots *slots = kvm_alloc_memslots();
 
                 if (!slots)
                         goto out_err_no_arch_destroy_vm;
                 /* Generations must be different for each address space. */
                 slots->generation = i;
                 rcu_assign_pointer(kvm->memslots[i], slots);
         }
 
         for (i = 0; i < KVM_NR_BUSES; i++) {
                 rcu_assign_pointer(kvm->buses[i],
                         kzalloc(sizeof(struct kvm_io_bus), GFP_KERNEL_ACCOUNT));
                 if (!kvm->buses[i])
                         goto out_err_no_arch_destroy_vm;
         }
 
         kvm->max_halt_poll_ns = halt_poll_ns;
 
         r = kvm_arch_init_vm(kvm, type);
         if (r)
                 goto out_err_no_arch_destroy_vm;
 
         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
 
         r = kvm_init_mmu_notifier(kvm);
         if (r)
                 goto out_err_no_mmu_notifier;
 
         r = kvm_arch_post_init_vm(kvm);
         if (r)
                 goto out_err;
 
         mutex_lock(&kvm_lock);
         list_add(&kvm->vm_list, &vm_list);
         mutex_unlock(&kvm_lock);
 
         preempt_notifier_inc();
         kvm_init_pm_notifier(kvm);
 
         return kvm;
 
 out_err:
 #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
         if (kvm->mmu_notifier.ops)
                 mmu_notifier_unregister(&kvm->mmu_notifier, current->mm);
 #endif
 out_err_no_mmu_notifier:
         hardware_disable_all();
 out_err_no_disable:
         kvm_arch_destroy_vm(kvm);
 out_err_no_arch_destroy_vm:
         WARN_ON_ONCE(!refcount_dec_and_test(&kvm->users_count));
         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));
         cleanup_srcu_struct(&kvm->irq_srcu);
 out_err_no_irq_srcu:
         cleanup_srcu_struct(&kvm->srcu);
 out_err_no_srcu:
         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_destroy_pm_notifier(kvm);
         kvm_uevent_notify_change(KVM_EVENT_DESTROY_VM, kvm);
         kvm_destroy_vm_debugfs(kvm);
         kvm_arch_sync_events(kvm);
         mutex_lock(&kvm_lock);
         list_del(&kvm->vm_list);
         mutex_unlock(&kvm_lock);
         kvm_arch_pre_destroy_vm(kvm);
 
         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);
 
 /*
  * Used to put a reference that was taken on behalf of an object associated
  * with a user-visible file descriptor, e.g. a vcpu or device, if installation
  * of the new file descriptor fails and the reference cannot be transferred to
  * its final owner.  In such cases, the caller is still actively using @kvm and
  * will fail miserably if the refcount unexpectedly hits zero.
  */
 void kvm_put_kvm_no_destroy(struct kvm *kvm)
 {
         WARN_ON(refcount_dec_and_test(&kvm->users_count));
 }
 EXPORT_SYMBOL_GPL(kvm_put_kvm_no_destroy);
 
 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 kvm_vm_ioctl_get_dirty_log() why this is needed.
  */
 static int kvm_alloc_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_ACCOUNT);
         if (!memslot->dirty_bitmap)
                 return -ENOMEM;
 
         return 0;
 }
 
 /*
  * Delete a memslot by decrementing the number of used slots and shifting all
  * other entries in the array forward one spot.
  */
 static inline void kvm_memslot_delete(struct kvm_memslots *slots,
                                       struct kvm_memory_slot *memslot)
 {
         struct kvm_memory_slot *mslots = slots->memslots;
         int i;
 
         if (WARN_ON(slots->id_to_index[memslot->id] == -1))
                 return;
 
         slots->used_slots--;
 
         if (atomic_read(&slots->lru_slot) >= slots->used_slots)
                 atomic_set(&slots->lru_slot, 0);
 
         for (i = slots->id_to_index[memslot->id]; i < slots->used_slots; i++) {
                 mslots[i] = mslots[i + 1];
                 slots->id_to_index[mslots[i].id] = i;
         }
         mslots[i] = *memslot;
         slots->id_to_index[memslot->id] = -1;
 }
 
 /*
  * "Insert" a new memslot by incrementing the number of used slots.  Returns
  * the new slot's initial index into the memslots array.
  */
 static inline int kvm_memslot_insert_back(struct kvm_memslots *slots)
 {
         return slots->used_slots++;
 }
 
 /*
  * Move a changed memslot backwards in the array by shifting existing slots
  * with a higher GFN toward the front of the array.  Note, the changed memslot
  * itself is not preserved in the array, i.e. not swapped at this time, only
  * its new index into the array is tracked.  Returns the changed memslot's
  * current index into the memslots array.
  */
 static inline int kvm_memslot_move_backward(struct kvm_memslots *slots,
                                             struct kvm_memory_slot *memslot)
 {
         struct kvm_memory_slot *mslots = slots->memslots;
         int i;
 
         if (WARN_ON_ONCE(slots->id_to_index[memslot->id] == -1) ||
             WARN_ON_ONCE(!slots->used_slots))
                 return -1;
 
         /*
          * Move the target memslot backward in the array by shifting existing
          * memslots with a higher GFN (than the target memslot) towards the
          * front of the array.
          */
         for (i = slots->id_to_index[memslot->id]; i < slots->used_slots - 1; i++) {
                 if (memslot->base_gfn > mslots[i + 1].base_gfn)
                         break;
 
                 WARN_ON_ONCE(memslot->base_gfn == mslots[i + 1].base_gfn);
 
                 /* Shift the next memslot forward one and update its index. */
                 mslots[i] = mslots[i + 1];
                 slots->id_to_index[mslots[i].id] = i;
         }
         return i;
 }
 
 /*
  * Move a changed memslot forwards in the array by shifting existing slots with
  * a lower GFN toward the back of the array.  Note, the changed memslot itself
  * is not preserved in the array, i.e. not swapped at this time, only its new
  * index into the array is tracked.  Returns the changed memslot's final index
  * into the memslots array.
  */
 static inline int kvm_memslot_move_forward(struct kvm_memslots *slots,
                                            struct kvm_memory_slot *memslot,
                                            int start)
 {
         struct kvm_memory_slot *mslots = slots->memslots;
         int i;
 
         for (i = start; i > 0; i--) {
                 if (memslot->base_gfn < mslots[i - 1].base_gfn)
                         break;
 
                 WARN_ON_ONCE(memslot->base_gfn == mslots[i - 1].base_gfn);
 
                 /* Shift the next memslot back one and update its index. */
                 mslots[i] = mslots[i - 1];
                 slots->id_to_index[mslots[i].id] = i;
         }
         return i;
 }
 
 /*
  * Re-sort memslots based on their GFN to account for an added, deleted, or
  * moved memslot.  Sorting memslots by GFN allows using a binary search during
  * memslot lookup.
  *
  * IMPORTANT: Slots are sorted from highest GFN to lowest GFN!  I.e. the entry
  * at memslots[0] has the highest GFN.
  *
  * The sorting algorithm takes advantage of having initially sorted memslots
  * and knowing the position of the changed memslot.  Sorting is also optimized
  * by not swapping the updated memslot and instead only shifting other memslots
  * and tracking the new index for the update memslot.  Only once its final
  * index is known is the updated memslot copied into its position in the array.
  *
  *  - When deleting a memslot, the deleted memslot simply needs to be moved to
  *    the end of the array.
  *
  *  - When creating a memslot, the algorithm "inserts" the new memslot at the
  *    end of the array and then it forward to its correct location.
  *
  *  - When moving a memslot, the algorithm first moves the updated memslot
  *    backward to handle the scenario where the memslot's GFN was changed to a
  *    lower value.  update_memslots() then falls through and runs the same flow
  *    as creating a memslot to move the memslot forward to handle the scenario
  *    where its GFN was changed to a higher value.
  *
  * Note, slots are sorted from highest->lowest instead of lowest->highest for
  * historical reasons.  Originally, invalid memslots where denoted by having
  * GFN=0, thus sorting from highest->lowest naturally sorted invalid memslots
  * to the end of the array.  The current algorithm uses dedicated logic to
  * delete a memslot and thus does not rely on invalid memslots having GFN=0.
  *
  * The other historical motiviation for highest->lowest was to improve the
  * performance of memslot lookup.  KVM originally used a linear search starting
  * at memslots[0].  On x86, the largest memslot usually has one of the highest,
  * if not *the* highest, GFN, as the bulk of the guest's RAM is located in a
  * single memslot above the 4gb boundary.  As the largest memslot is also the
  * most likely to be referenced, sorting it to the front of the array was
  * advantageous.  The current binary search starts from the middle of the array
  * and uses an LRU pointer to improve performance for all memslots and GFNs.
  */
 static void update_memslots(struct kvm_memslots *slots,
                             struct kvm_memory_slot *memslot,
                             enum kvm_mr_change change)
 {
         int i;
 
         if (change == KVM_MR_DELETE) {
                 kvm_memslot_delete(slots, memslot);
         } else {
                 if (change == KVM_MR_CREATE)
                         i = kvm_memslot_insert_back(slots);
                 else
                         i = kvm_memslot_move_backward(slots, memslot);
                 i = kvm_memslot_move_forward(slots, memslot, i);
 
                 /*
                  * Copy the memslot to its new position in memslots and update
                  * its index accordingly.
                  */
                 slots->memslots[i] = *memslot;
                 slots->id_to_index[memslot->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 = old_memslots->generation;
 
         WARN_ON(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS);
         slots->generation = gen | KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS;
 
         rcu_assign_pointer(kvm->memslots[as_id], slots);
 
         /*
          * Acquired in kvm_set_memslot. Must be released before synchronize
          * SRCU below in order to avoid deadlock with another thread
          * acquiring the slots_arch_lock in an srcu critical section.
          */
         mutex_unlock(&kvm->slots_arch_lock);
 
         synchronize_srcu_expedited(&kvm->srcu);
 
         /*
          * Increment the new memslot generation a second time, dropping the
          * update in-progress flag and incrementing the generation based on
          * the number of address spaces.  This provides a unique and easily
          * identifiable generation number while the memslots are in flux.
          */
         gen = slots->generation & ~KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS;
 
         /*
          * 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, 2, 4, ... while address space 1 will
          * use generations 1, 3, 5, ...
          */
         gen += KVM_ADDRESS_SPACE_NUM;
 
         kvm_arch_memslots_updated(kvm, gen);
 
         slots->generation = gen;
 
         return old_memslots;
 }
 
 static size_t kvm_memslots_size(int slots)
 {
         return sizeof(struct kvm_memslots) +
                (sizeof(struct kvm_memory_slot) * slots);
 }
 
 static void kvm_copy_memslots(struct kvm_memslots *to,
                               struct kvm_memslots *from)
 {
         memcpy(to, from, kvm_memslots_size(from->used_slots));
 }
 
 /*
  * Note, at a minimum, the current number of used slots must be allocated, even
  * when deleting a memslot, as we need a complete duplicate of the memslots for
  * use when invalidating a memslot prior to deleting/moving the memslot.
  */
 static struct kvm_memslots *kvm_dup_memslots(struct kvm_memslots *old,
                                              enum kvm_mr_change change)
 {
         struct kvm_memslots *slots;
         size_t new_size;
 
         if (change == KVM_MR_CREATE)
                 new_size = kvm_memslots_size(old->used_slots + 1);
         else
                 new_size = kvm_memslots_size(old->used_slots);
 
         slots = kvzalloc(new_size, GFP_KERNEL_ACCOUNT);
         if (likely(slots))
                 kvm_copy_memslots(slots, old);
 
         return slots;
 }
 
 static int kvm_set_memslot(struct kvm *kvm,
                            const struct kvm_userspace_memory_region *mem,
                            struct kvm_memory_slot *old,
                            struct kvm_memory_slot *new, int as_id,
                            enum kvm_mr_change change)
 {
         struct kvm_memory_slot *slot;
         struct kvm_memslots *slots;
         int r;
 
         /*
          * Released in install_new_memslots.
          *
          * Must be held from before the current memslots are copied until
          * after the new memslots are installed with rcu_assign_pointer,
          * then released before the synchronize srcu in install_new_memslots.
          *
          * When modifying memslots outside of the slots_lock, must be held
          * before reading the pointer to the current memslots until after all
          * changes to those memslots are complete.
          *
          * These rules ensure that installing new memslots does not lose
          * changes made to the previous memslots.
          */
         mutex_lock(&kvm->slots_arch_lock);
 
         slots = kvm_dup_memslots(__kvm_memslots(kvm, as_id), change);
         if (!slots) {
                 mutex_unlock(&kvm->slots_arch_lock);
                 return -ENOMEM;
         }
 
         if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) {
                 /*
                  * Note, the INVALID flag needs to be in the appropriate entry
                  * in the freshly allocated memslots, not in @old or @new.
                  */
                 slot = id_to_memslot(slots, old->id);
                 slot->flags |= KVM_MEMSLOT_INVALID;
 
                 /*
                  * We can re-use the memory from the old memslots.
                  * It will be overwritten with a copy of the new memslots
                  * after reacquiring the slots_arch_lock below.
                  */
                 slots = 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_root)
                  */
                 kvm_arch_flush_shadow_memslot(kvm, slot);
 
                 /* Released in install_new_memslots. */
                 mutex_lock(&kvm->slots_arch_lock);
 
                 /*
                  * The arch-specific fields of the memslots could have changed
                  * between releasing the slots_arch_lock in
                  * install_new_memslots and here, so get a fresh copy of the
                  * slots.
                  */
                 kvm_copy_memslots(slots, __kvm_memslots(kvm, as_id));
         }
 
         r = kvm_arch_prepare_memory_region(kvm, new, mem, change);
         if (r)
                 goto out_slots;
 
         update_memslots(slots, new, change);
         slots = install_new_memslots(kvm, as_id, slots);
 
         kvm_arch_commit_memory_region(kvm, mem, old, new, change);
 
         kvfree(slots);
         return 0;
 
 out_slots:
         if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) {
                 slot = id_to_memslot(slots, old->id);
                 slot->flags &= ~KVM_MEMSLOT_INVALID;
                 slots = install_new_memslots(kvm, as_id, slots);
         } else {
                 mutex_unlock(&kvm->slots_arch_lock);
         }
         kvfree(slots);
         return r;
 }
 
 static int kvm_delete_memslot(struct kvm *kvm,
                               const struct kvm_userspace_memory_region *mem,
                               struct kvm_memory_slot *old, int as_id)
 {
         struct kvm_memory_slot new;
         int r;
 
         if (!old->npages)
                 return -EINVAL;
 
         memset(&new, 0, sizeof(new));
         new.id = old->id;
         /*
          * This is only for debugging purpose; it should never be referenced
          * for a removed memslot.
          */
         new.as_id = as_id;
 
         r = kvm_set_memslot(kvm, mem, old, &new, as_id, KVM_MR_DELETE);
         if (r)
                 return r;
 
         kvm_free_memslot(kvm, old);
         return 0;
 }
 
 /*
  * 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)
 {
         struct kvm_memory_slot old, new;
         struct kvm_memory_slot *tmp;
         enum kvm_mr_change change;
         int as_id, id;
         int r;
 
         r = check_memory_region_flags(mem);
         if (r)
                 return r;
 
         as_id = mem->slot >> 16;
         id = (u16)mem->slot;
 
         /* General sanity checks */
         if (mem->memory_size & (PAGE_SIZE - 1))
                 return -EINVAL;
         if (mem->guest_phys_addr & (PAGE_SIZE - 1))
                 return -EINVAL;
         /* We can read the guest memory with __xxx_user() later on. */
         if ((mem->userspace_addr & (PAGE_SIZE - 1)) ||
             (mem->userspace_addr != untagged_addr(mem->userspace_addr)) ||
              !access_ok((void __user *)(unsigned long)mem->userspace_addr,
                         mem->memory_size))
                 return -EINVAL;
         if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_MEM_SLOTS_NUM)
                 return -EINVAL;
         if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr)
                 return -EINVAL;
 
         /*
          * Make a full copy of the old memslot, the pointer will become stale
          * when the memslots are re-sorted by update_memslots(), and the old
          * memslot needs to be referenced after calling update_memslots(), e.g.
          * to free its resources and for arch specific behavior.
          */
         tmp = id_to_memslot(__kvm_memslots(kvm, as_id), id);
         if (tmp) {
                 old = *tmp;
                 tmp = NULL;
         } else {
                 memset(&old, 0, sizeof(old));
                 old.id = id;
         }
 
         if (!mem->memory_size)
                 return kvm_delete_memslot(kvm, mem, &old, as_id);
 
         new.as_id = as_id;
         new.id = id;
         new.base_gfn = mem->guest_phys_addr >> PAGE_SHIFT;
         new.npages = mem->memory_size >> PAGE_SHIFT;
         new.flags = mem->flags;
         new.userspace_addr = mem->userspace_addr;
 
         if (new.npages > KVM_MEM_MAX_NR_PAGES)
                 return -EINVAL;
 
         if (!old.npages) {
                 change = KVM_MR_CREATE;
                 new.dirty_bitmap = NULL;
                 memset(&new.arch, 0, sizeof(new.arch));
         } else { /* Modify an existing slot. */
                 if ((new.userspace_addr != old.userspace_addr) ||
                     (new.npages != old.npages) ||
                     ((new.flags ^ old.flags) & KVM_MEM_READONLY))
                         return -EINVAL;
 
                 if (new.base_gfn != old.base_gfn)
                         change = KVM_MR_MOVE;
                 else if (new.flags != old.flags)
                         change = KVM_MR_FLAGS_ONLY;
                 else /* Nothing to change. */
                         return 0;
 
                 /* Copy dirty_bitmap and arch from the current memslot. */
                 new.dirty_bitmap = old.dirty_bitmap;
                 memcpy(&new.arch, &old.arch, sizeof(new.arch));
         }
 
         if ((change == KVM_MR_CREATE) || (change == KVM_MR_MOVE)) {
                 /* Check for overlaps */
                 kvm_for_each_memslot(tmp, __kvm_memslots(kvm, as_id)) {
                         if (tmp->id == id)
                                 continue;
                         if (!((new.base_gfn + new.npages <= tmp->base_gfn) ||
                               (new.base_gfn >= tmp->base_gfn + tmp->npages)))
                                 return -EEXIST;
                 }
         }
 
         /* Allocate/free page dirty bitmap as needed */
         if (!(new.flags & KVM_MEM_LOG_DIRTY_PAGES))
                 new.dirty_bitmap = NULL;
         else if (!new.dirty_bitmap && !kvm->dirty_ring_size) {
                 r = kvm_alloc_dirty_bitmap(&new);
                 if (r)
                         return r;
 
                 if (kvm_dirty_log_manual_protect_and_init_set(kvm))
                         bitmap_set(new.dirty_bitmap, 0, new.npages);
         }
 
         r = kvm_set_memslot(kvm, mem, &old, &new, as_id, change);
         if (r)
                 goto out_bitmap;
 
         if (old.dirty_bitmap && !new.dirty_bitmap)
                 kvm_destroy_dirty_bitmap(&old);
         return 0;
 
 out_bitmap:
         if (new.dirty_bitmap && !old.dirty_bitmap)
                 kvm_destroy_dirty_bitmap(&new);
         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);
 }
 
 #ifndef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
 /**
  * kvm_get_dirty_log - get a snapshot of dirty pages
  * @kvm:        pointer to kvm instance
  * @log:        slot id and address to which we copy the log
  * @is_dirty:   set to '1' if any dirty pages were found
  * @memslot:    set to the associated memslot, always valid on success
  */
 int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log,
                       int *is_dirty, struct kvm_memory_slot **memslot)
 {
         struct kvm_memslots *slots;
         int i, as_id, id;
         unsigned long n;
         unsigned long any = 0;
 
         /* Dirty ring tracking is exclusive to dirty log tracking */
         if (kvm->dirty_ring_size)
                 return -ENXIO;
 
         *memslot = NULL;
         *is_dirty = 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) || !(*memslot)->dirty_bitmap)
                 return -ENOENT;
 
         kvm_arch_sync_dirty_log(kvm, *memslot);
 
         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);
 
 #else /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
 /**
  * kvm_get_dirty_log_protect - get a snapshot of dirty 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
  *
  * 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.
  *
  */
 static int kvm_get_dirty_log_protect(struct kvm *kvm, struct kvm_dirty_log *log)
 {
         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;
         bool flush;
 
         /* Dirty ring tracking is exclusive to dirty log tracking */
         if (kvm->dirty_ring_size)
                 return -ENXIO;
 
         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 || !memslot->dirty_bitmap)
                 return -ENOENT;
 
         dirty_bitmap = memslot->dirty_bitmap;
 
         kvm_arch_sync_dirty_log(kvm, memslot);
 
         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);
 
                 KVM_MMU_LOCK(kvm);
                 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;
 
                         offset = i * BITS_PER_LONG;
                         kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot,
                                                                 offset, mask);
                 }
                 KVM_MMU_UNLOCK(kvm);
         }
 
         if (flush)
                 kvm_arch_flush_remote_tlbs_memslot(kvm, memslot);
 
         if (copy_to_user(log->dirty_bitmap, dirty_bitmap_buffer, n))
                 return -EFAULT;
         return 0;
 }
 
 
 /**
  * kvm_vm_ioctl_get_dirty_log - get and clear the log of dirty pages in a slot
  * @kvm: kvm instance
  * @log: slot id and address to which we copy the log
  *
  * Steps 1-4 below provide general overview of dirty page logging. See
  * kvm_get_dirty_log_protect() function description for additional details.
  *
  * We call kvm_get_dirty_log_protect() to handle steps 1-3, upon return we
  * always flush the TLB (step 4) even if previous step failed  and the dirty
  * bitmap may be corrupt. Regardless of previous outcome the KVM logging API
  * does not preclude user space subsequent dirty log read. Flushing TLB ensures
  * writes will be marked dirty for next log read.
  *
  *   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. Flush TLB's if needed.
  */
 static int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
                                       struct kvm_dirty_log *log)
 {
         int r;
 
         mutex_lock(&kvm->slots_lock);
 
         r = kvm_get_dirty_log_protect(kvm, log);
 
         mutex_unlock(&kvm->slots_lock);
         return r;
 }
 
 /**
  * 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
  */
 static int kvm_clear_dirty_log_protect(struct kvm *kvm,
                                        struct kvm_clear_dirty_log *log)
 {
         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;
         bool flush;
 
         /* Dirty ring tracking is exclusive to dirty log tracking */
         if (kvm->dirty_ring_size)
                 return -ENXIO;
 
         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);
         if (!memslot || !memslot->dirty_bitmap)
                 return -ENOENT;
 
         dirty_bitmap = memslot->dirty_bitmap;
 
         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;
 
         kvm_arch_sync_dirty_log(kvm, memslot);
 
         flush = false;
         dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot);
         if (copy_from_user(dirty_bitmap_buffer, log->dirty_bitmap, n))
                 return -EFAULT;
 
         KVM_MMU_LOCK(kvm);
         for (offset = log->first_page, i = offset / BITS_PER_LONG,
                  n = DIV_ROUND_UP(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);
                 }
         }
         KVM_MMU_UNLOCK(kvm);
 
         if (flush)
                 kvm_arch_flush_remote_tlbs_memslot(kvm, memslot);
 
         return 0;
 }
 
 static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
                                         struct kvm_clear_dirty_log *log)
 {
         int r;
 
         mutex_lock(&kvm->slots_lock);
 
         r = kvm_clear_dirty_log_protect(kvm, log);
 
         mutex_unlock(&kvm->slots_lock);
         return r;
 }
 #endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
 
 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);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_memslot);
 
 bool kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
 {
         struct kvm_memory_slot *memslot = gfn_to_memslot(kvm, gfn);
 
         return kvm_is_visible_memslot(memslot);
 }
 EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);
 
 bool kvm_vcpu_is_visible_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
 {
         struct kvm_memory_slot *memslot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
 
         return kvm_is_visible_memslot(memslot);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_is_visible_gfn);
 
 unsigned long kvm_host_page_size(struct kvm_vcpu *vcpu, gfn_t gfn)
 {
         struct vm_area_struct *vma;
         unsigned long addr, size;
 
         size = PAGE_SIZE;
 
         addr = kvm_vcpu_gfn_to_hva_prot(vcpu, gfn, NULL);
         if (kvm_is_error_hva(addr))
                 return PAGE_SIZE;
 
         mmap_read_lock(current->mm);
         vma = find_vma(current->mm, addr);
         if (!vma)
                 goto out;
 
         size = vma_kernel_pagesize(vma);
 
 out:
         mmap_read_unlock(current->mm);
 
         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 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];
 
         /*
          * 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;
 
         if (get_user_page_fast_only(addr, FOLL_WRITE, page)) {
                 *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_page_fast_only(addr, FOLL_WRITE, &wpage)) {
                         *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 kvm_try_get_pfn(kvm_pfn_t pfn)
 {
         if (kvm_is_reserved_pfn(pfn))
                 return 1;
         return get_page_unless_zero(pfn_to_page(pfn));
 }
 
 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)
 {
         kvm_pfn_t pfn;
         pte_t *ptep;
         spinlock_t *ptl;
         int r;
 
         r = follow_pte(vma->vm_mm, addr, &ptep, &ptl);
         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->mm, addr,
                                      (write_fault ? FAULT_FLAG_WRITE : 0),
                                      &unlocked);
                 if (unlocked)
                         return -EAGAIN;
                 if (r)
                         return r;
 
                 r = follow_pte(vma->vm_mm, addr, &ptep, &ptl);
                 if (r)
                         return r;
         }
 
         if (write_fault && !pte_write(*ptep)) {
                 pfn = KVM_PFN_ERR_RO_FAULT;
                 goto out;
         }
 
         if (writable)
                 *writable = pte_write(*ptep);
         pfn = pte_pfn(*ptep);
 
         /*
          * 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.
          *
          * Certain IO or PFNMAP mappings can be backed with valid
          * struct pages, but be allocated without refcounting e.g.,
          * tail pages of non-compound higher order allocations, which
          * would then underflow the refcount when the caller does the
          * required put_page. Don't allow those pages here.
          */ 
         if (!kvm_try_get_pfn(pfn))
                 r = -EFAULT;
 
 out:
         pte_unmap_unlock(ptep, ptl);
         *p_pfn = pfn;
 
         return r;
 }
 
 /*
  * 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;
 
         mmap_read_lock(current->mm);
         if (npages == -EHWPOISON ||
               (!async && check_user_page_hwpoison(addr))) {
                 pfn = KVM_PFN_ERR_HWPOISON;
                 goto exit;
         }
 
 retry:
         vma = vma_lookup(current->mm, addr);
 
         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:
         mmap_read_unlock(current->mm);
         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, hva_t *hva)
 {
         unsigned long addr = __gfn_to_hva_many(slot, gfn, NULL, write_fault);
 
         if (hva)
                 *hva = addr;
 
         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, NULL);
 }
 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, 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, NULL);
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot_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_only(addr, nr_pages, FOLL_WRITE, 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);
 
 void kvm_release_pfn(kvm_pfn_t pfn, bool dirty, struct gfn_to_pfn_cache *cache)
 {
         if (pfn == 0)
                 return;
 
         if (cache)
                 cache->pfn = cache->gfn = 0;
 
         if (dirty)
                 kvm_release_pfn_dirty(pfn);
         else
                 kvm_release_pfn_clean(pfn);
 }
 
 static void kvm_cache_gfn_to_pfn(struct kvm_memory_slot *slot, gfn_t gfn,
                                  struct gfn_to_pfn_cache *cache, u64 gen)
 {
         kvm_release_pfn(cache->pfn, cache->dirty, cache);
 
         cache->pfn = gfn_to_pfn_memslot(slot, gfn);
         cache->gfn = gfn;
         cache->dirty = false;
         cache->generation = gen;
 }
 
 static int __kvm_map_gfn(struct kvm_memslots *slots, gfn_t gfn,
                          struct kvm_host_map *map,
                          struct gfn_to_pfn_cache *cache,
                          bool atomic)
 {
         kvm_pfn_t pfn;
         void *hva = NULL;
         struct page *page = KVM_UNMAPPED_PAGE;
         struct kvm_memory_slot *slot = __gfn_to_memslot(slots, gfn);
         u64 gen = slots->generation;
 
         if (!map)
                 return -EINVAL;
 
         if (cache) {
                 if (!cache->pfn || cache->gfn != gfn ||
                         cache->generation != gen) {
                         if (atomic)
                                 return -EAGAIN;
                         kvm_cache_gfn_to_pfn(slot, gfn, cache, gen);
                 }
                 pfn = cache->pfn;
         } else {
                 if (atomic)
                         return -EAGAIN;
                 pfn = gfn_to_pfn_memslot(slot, gfn);
         }
         if (is_error_noslot_pfn(pfn))
                 return -EINVAL;
 
         if (pfn_valid(pfn)) {
                 page = pfn_to_page(pfn);
                 if (atomic)
                         hva = kmap_atomic(page);
                 else
                         hva = kmap(page);
 #ifdef CONFIG_HAS_IOMEM
         } else if (!atomic) {
                 hva = memremap(pfn_to_hpa(pfn), PAGE_SIZE, MEMREMAP_WB);
         } else {
                 return -EINVAL;
 #endif
         }
 
         if (!hva)
                 return -EFAULT;
 
         map->page = page;
         map->hva = hva;
         map->pfn = pfn;
         map->gfn = gfn;
 
         return 0;
 }
 
 int kvm_map_gfn(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map,
                 struct gfn_to_pfn_cache *cache, bool atomic)
 {
         return __kvm_map_gfn(kvm_memslots(vcpu->kvm), gfn, map,
                         cache, atomic);
 }
 EXPORT_SYMBOL_GPL(kvm_map_gfn);
 
 int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map)
 {
         return __kvm_map_gfn(kvm_vcpu_memslots(vcpu), gfn, map,
                 NULL, false);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_map);
 
 static void __kvm_unmap_gfn(struct kvm *kvm,
                         struct kvm_memory_slot *memslot,
                         struct kvm_host_map *map,
                         struct gfn_to_pfn_cache *cache,
                         bool dirty, bool atomic)
 {
         if (!map)
                 return;
 
         if (!map->hva)
                 return;
 
         if (map->page != KVM_UNMAPPED_PAGE) {
                 if (atomic)
                         kunmap_atomic(map->hva);
                 else
                         kunmap(map->page);
         }
 #ifdef CONFIG_HAS_IOMEM
         else if (!atomic)
                 memunmap(map->hva);
         else
                 WARN_ONCE(1, "Unexpected unmapping in atomic context");
 #endif
 
         if (dirty)
                 mark_page_dirty_in_slot(kvm, memslot, map->gfn);
 
         if (cache)
                 cache->dirty |= dirty;
         else
                 kvm_release_pfn(map->pfn, dirty, NULL);
 
         map->hva = NULL;
         map->page = NULL;
 }
 
 int kvm_unmap_gfn(struct kvm_vcpu *vcpu, struct kvm_host_map *map, 
                   struct gfn_to_pfn_cache *cache, bool dirty, bool atomic)
 {
         __kvm_unmap_gfn(vcpu->kvm, gfn_to_memslot(vcpu->kvm, map->gfn), map,
                         cache, dirty, atomic);
         return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_unmap_gfn);
 
 void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map, bool dirty)
 {
         __kvm_unmap_gfn(vcpu->kvm, kvm_vcpu_gfn_to_memslot(vcpu, map->gfn),
                         map, NULL, dirty, false);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_unmap);
 
 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) && !kvm_is_zone_device_pfn(pfn))
                 SetPageDirty(pfn_to_page(pfn));
 }
 EXPORT_SYMBOL_GPL(kvm_set_pfn_dirty);
 
 void kvm_set_pfn_accessed(kvm_pfn_t pfn)
 {
         if (!kvm_is_reserved_pfn(pfn) && !kvm_is_zone_device_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_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 *kvm,
                                   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(kvm, 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(kvm, 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(vcpu->kvm, 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;
 
         /* Update ghc->generation before performing any error checks. */
         ghc->generation = slots->generation;
 
         if (start_gfn > end_gfn) {
                 ghc->hva = KVM_HVA_ERR_BAD;
                 return -EINVAL;
         }
 
         /*
          * If the requested region crosses two memslots, we still
          * verify that the entire region is valid here.
          */
         for ( ; start_gfn <= end_gfn; start_gfn += nr_pages_avail) {
                 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))
                         return -EFAULT;
         }
 
         /* Use the slow path for cross page reads and writes. */
         if (nr_pages_needed == 1)
                 ghc->hva += offset;
         else
                 ghc->memslot = NULL;
 
         ghc->gpa = gpa;
         ghc->len = len;
         return 0;
 }
 
 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) {
                 if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len))
                         return -EFAULT;
         }
 
         if (kvm_is_error_hva(ghc->hva))
                 return -EFAULT;
 
         if (unlikely(!ghc->memslot))
                 return kvm_write_guest(kvm, gpa, data, len);
 
         r = __copy_to_user((void __user *)ghc->hva + offset, data, len);
         if (r)
                 return -EFAULT;
         mark_page_dirty_in_slot(kvm, 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_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) {
                 if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len))
                         return -EFAULT;
         }
 
         if (kvm_is_error_hva(ghc->hva))
                 return -EFAULT;
 
         if (unlikely(!ghc->memslot))
                 return kvm_read_guest(kvm, gpa, data, len);
 
         r = __copy_from_user(data, (void __user *)ghc->hva + offset, len);
         if (r)
                 return -EFAULT;
 
         return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_read_guest_offset_cached);
 
 int kvm_read_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
                           void *data, unsigned long len)
 {
         return kvm_read_guest_offset_cached(kvm, ghc, data, 0, len);
 }
 EXPORT_SYMBOL_GPL(kvm_read_guest_cached);
 
 int kvm_clear_guest(struct kvm *kvm, gpa_t gpa, unsigned long len)
 {
         const void *zero_page = (const void *) __va(page_to_phys(ZERO_PAGE(0)));
         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, zero_page, offset, len);
                 if (ret < 0)
                         return ret;
                 offset = 0;
                 len -= seg;
                 ++gfn;
         }
         return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_clear_guest);
 
 void mark_page_dirty_in_slot(struct kvm *kvm,
                              struct kvm_memory_slot *memslot,
                              gfn_t gfn)
 {
         if (memslot && kvm_slot_dirty_track_enabled(memslot)) {
                 unsigned long rel_gfn = gfn - memslot->base_gfn;
                 u32 slot = (memslot->as_id << 16) | memslot->id;
 
                 if (kvm->dirty_ring_size)
                         kvm_dirty_ring_push(kvm_dirty_ring_get(kvm),
                                             slot, rel_gfn);
                 else
                         set_bit_le(rel_gfn, memslot->dirty_bitmap);
         }
 }
 EXPORT_SYMBOL_GPL(mark_page_dirty_in_slot);
 
 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(kvm, 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(vcpu->kvm, 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, grow_start;
 
         old = val = vcpu->halt_poll_ns;
         grow_start = READ_ONCE(halt_poll_ns_grow_start);
         grow = READ_ONCE(halt_poll_ns_grow);
         if (!grow)
                 goto out;
 
         val *= grow;
         if (val < grow_start)
                 val = grow_start;
 
         if (val > vcpu->kvm->max_halt_poll_ns)
                 val = vcpu->kvm->max_halt_poll_ns;
 
         vcpu->halt_poll_ns = val;
 out:
         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, grow_start;
 
         old = val = vcpu->halt_poll_ns;
         shrink = READ_ONCE(halt_poll_ns_shrink);
         grow_start = READ_ONCE(halt_poll_ns_grow_start);
         if (shrink == 0)
                 val = 0;
         else
                 val /= shrink;
 
         if (val < grow_start)
                 val = 0;
 
         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;
         if (kvm_check_request(KVM_REQ_UNBLOCK, vcpu))
                 goto out;
 
         ret = 0;
 out:
         srcu_read_unlock(&vcpu->kvm->srcu, idx);
         return ret;
 }
 
 static inline void
 update_halt_poll_stats(struct kvm_vcpu *vcpu, u64 poll_ns, bool waited)
 {
         if (waited)
                 vcpu->stat.generic.halt_poll_fail_ns += poll_ns;
         else
                 vcpu->stat.generic.halt_poll_success_ns += poll_ns;
 }
 
 /*
  * The vCPU has executed a HLT instruction with in-kernel mode enabled.
  */
 void kvm_vcpu_block(struct kvm_vcpu *vcpu)
 {
         ktime_t start, cur, poll_end;
         bool waited = false;
         u64 block_ns;
 
         kvm_arch_vcpu_blocking(vcpu);
 
         start = cur = poll_end = ktime_get();
         if (vcpu->halt_poll_ns && !kvm_arch_no_poll(vcpu)) {
                 ktime_t stop = ktime_add_ns(ktime_get(), vcpu->halt_poll_ns);
 
                 ++vcpu->stat.generic.halt_attempted_poll;
                 do {
                         /*
                          * This sets KVM_REQ_UNHALT if an interrupt
                          * arrives.
                          */
                         if (kvm_vcpu_check_block(vcpu) < 0) {
                                 ++vcpu->stat.generic.halt_successful_poll;
                                 if (!vcpu_valid_wakeup(vcpu))
                                         ++vcpu->stat.generic.halt_poll_invalid;
                                 goto out;
                         }
                         cpu_relax();
                         poll_end = cur = ktime_get();
                 } while (kvm_vcpu_can_poll(cur, stop));
         }
 
         prepare_to_rcuwait(&vcpu->wait);
         for (;;) {
                 set_current_state(TASK_INTERRUPTIBLE);
 
                 if (kvm_vcpu_check_block(vcpu) < 0)
                         break;
 
                 waited = true;
                 schedule();
         }
         finish_rcuwait(&vcpu->wait);
         cur = ktime_get();
 out:
         kvm_arch_vcpu_unblocking(vcpu);
         block_ns = ktime_to_ns(cur) - ktime_to_ns(start);
 
         update_halt_poll_stats(
                 vcpu, ktime_to_ns(ktime_sub(poll_end, start)), waited);
 
         if (!kvm_arch_no_poll(vcpu)) {
                 if (!vcpu_valid_wakeup(vcpu)) {
                         shrink_halt_poll_ns(vcpu);
                 } else if (vcpu->kvm->max_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 > vcpu->kvm->max_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 < vcpu->kvm->max_halt_poll_ns &&
                                         block_ns < vcpu->kvm->max_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 rcuwait *waitp;
 
         waitp = kvm_arch_vcpu_get_wait(vcpu);
         if (rcuwait_wake_up(waitp)) {
                 WRITE_ONCE(vcpu->ready, true);
                 ++vcpu->stat.generic.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 beginning 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
 }
 
 /*
  * Unlike kvm_arch_vcpu_runnable, this function is called outside
  * a vcpu_load/vcpu_put pair.  However, for most architectures
  * kvm_arch_vcpu_runnable does not require vcpu_load.
  */
 bool __weak kvm_arch_dy_runnable(struct kvm_vcpu *vcpu)
 {
         return kvm_arch_vcpu_runnable(vcpu);
 }
 
 static bool vcpu_dy_runnable(struct kvm_vcpu *vcpu)
 {
         if (kvm_arch_dy_runnable(vcpu))
                 return true;
 
 #ifdef CONFIG_KVM_ASYNC_PF
         if (!list_empty_careful(&vcpu->async_pf.done))
                 return true;
 #endif
 
         return false;
 }
 
 bool __weak kvm_arch_dy_has_pending_interrupt(struct kvm_vcpu *vcpu)
 {
         return false;
 }
 
 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->ready))
                                 continue;
                         if (vcpu == me)
                                 continue;
                         if (rcuwait_active(&vcpu->wait) &&
                             !vcpu_dy_runnable(vcpu))
                                 continue;
                         if (READ_ONCE(vcpu->preempted) && yield_to_kernel_mode &&
                             !kvm_arch_dy_has_pending_interrupt(vcpu) &&
                             !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 bool kvm_page_in_dirty_ring(struct kvm *kvm, unsigned long pgoff)
 {
 #if KVM_DIRTY_LOG_PAGE_OFFSET > 0
         return (pgoff >= KVM_DIRTY_LOG_PAGE_OFFSET) &&
             (pgoff < KVM_DIRTY_LOG_PAGE_OFFSET +
              kvm->dirty_ring_size / PAGE_SIZE);
 #else
         return false;
 #endif
 }
 
 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 if (kvm_page_in_dirty_ring(vcpu->kvm, vmf->pgoff))
                 page = kvm_dirty_ring_get_page(
                     &vcpu->dirty_ring,
                     vmf->pgoff - KVM_DIRTY_LOG_PAGE_OFFSET);
         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)
 {
         struct kvm_vcpu *vcpu = file->private_data;
         unsigned long pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
 
         if ((kvm_page_in_dirty_ring(vcpu->kvm, vma->vm_pgoff) ||
              kvm_page_in_dirty_ring(vcpu->kvm, vma->vm_pgoff + pages - 1)) &&
             ((vma->vm_flags & VM_EXEC) || !(vma->vm_flags & VM_SHARED)))
                 return -EINVAL;
 
         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;
 
         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 void kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu)
 {
 #ifdef __KVM_HAVE_ARCH_VCPU_DEBUGFS
         struct dentry *debugfs_dentry;
         char dir_name[ITOA_MAX_LEN * 2];
 
         if (!debugfs_initialized())
                 return;
 
         snprintf(dir_name, sizeof(dir_name), "vcpu%d", vcpu->vcpu_id);
         debugfs_dentry = debugfs_create_dir(dir_name,
                                             vcpu->kvm->debugfs_dentry);
 
         kvm_arch_create_vcpu_debugfs(vcpu, debugfs_dentry);
 #endif
 }
 
 /*
  * 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;
         struct page *page;
 
         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);
 
         r = kvm_arch_vcpu_precreate(kvm, id);
         if (r)
                 goto vcpu_decrement;
 
         vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL_ACCOUNT);
         if (!vcpu) {
                 r = -ENOMEM;
                 goto vcpu_decrement;
         }
 
         BUILD_BUG_ON(sizeof(struct kvm_run) > PAGE_SIZE);
         page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
         if (!page) {
                 r = -ENOMEM;
                 goto vcpu_free;
         }
         vcpu->run = page_address(page);
 
         kvm_vcpu_init(vcpu, kvm, id);
 
         r = kvm_arch_vcpu_create(vcpu);
         if (r)
                 goto vcpu_free_run_page;
 
         if (kvm->dirty_ring_size) {
                 r = kvm_dirty_ring_alloc(&vcpu->dirty_ring,
                                          id, kvm->dirty_ring_size);
                 if (r)
                         goto arch_vcpu_destroy;
         }
 
         mutex_lock(&kvm->lock);
         if (kvm_get_vcpu_by_id(kvm, id)) {
                 r = -EEXIST;
                 goto unlock_vcpu_destroy;
         }
 
         vcpu->vcpu_idx = atomic_read(&kvm->online_vcpus);
         BUG_ON(kvm->vcpus[vcpu->vcpu_idx]);
 
         /* Fill the stats id string for the vcpu */
         snprintf(vcpu->stats_id, sizeof(vcpu->stats_id), "kvm-%d/vcpu-%d",
                  task_pid_nr(current), id);
 
         /* 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_no_destroy(kvm);
                 goto unlock_vcpu_destroy;
         }
 
         kvm->vcpus[vcpu->vcpu_idx] = 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);
         kvm_create_vcpu_debugfs(vcpu);
         return r;
 
 unlock_vcpu_destroy:
         mutex_unlock(&kvm->lock);
         kvm_dirty_ring_free(&vcpu->dirty_ring);
 arch_vcpu_destroy:
         kvm_arch_vcpu_destroy(vcpu);
 vcpu_free_run_page:
         free_page((unsigned long)vcpu->run);
 vcpu_free:
         kmem_cache_free(kvm_vcpu_cache, 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 ssize_t kvm_vcpu_stats_read(struct file *file, char __user *user_buffer,
                               size_t size, loff_t *offset)
 {
         struct kvm_vcpu *vcpu = file->private_data;
 
         return kvm_stats_read(vcpu->stats_id, &kvm_vcpu_stats_header,
                         &kvm_vcpu_stats_desc[0], &vcpu->stat,
                         sizeof(vcpu->stat), user_buffer, size, offset);
 }
 
 static const struct file_operations kvm_vcpu_stats_fops = {
         .read = kvm_vcpu_stats_read,
         .llseek = noop_llseek,
 };
 
 static int kvm_vcpu_ioctl_get_stats_fd(struct kvm_vcpu *vcpu)
 {
         int fd;
         struct file *file;
         char name[15 + ITOA_MAX_LEN + 1];
 
         snprintf(name, sizeof(name), "kvm-vcpu-stats:%d", vcpu->vcpu_id);
 
         fd = get_unused_fd_flags(O_CLOEXEC);
         if (fd < 0)
                 return fd;
 
         file = anon_inode_getfile(name, &kvm_vcpu_stats_fops, vcpu, O_RDONLY);
         if (IS_ERR(file)) {
                 put_unused_fd(fd);
                 return PTR_ERR(file);
         }
         file->f_mode |= FMODE_PREAD;
         fd_install(fd, file);
 
         return fd;
 }
 
 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);
                 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_ACCOUNT);
                 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;
 
                 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_ACCOUNT);
                 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_ACCOUNT);
                 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;
         }
         case KVM_GET_STATS_FD: {
                 r = kvm_vcpu_ioctl_get_stats_fd(vcpu);
                 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,
                                               (compat_sigset_t __user *)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_mmap(struct file *filp, struct vm_area_struct *vma)
 {
         struct kvm_device *dev = filp->private_data;
 
         if (dev->ops->mmap)
                 return dev->ops->mmap(dev, vma);
 
         return -ENODEV;
 }
 
 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;
 
         if (dev->ops->release) {
                 mutex_lock(&kvm->lock);
                 list_del(&dev->vm_node);
                 dev->ops->release(dev);
                 mutex_unlock(&kvm->lock);
         }
 
         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),
         .mmap = kvm_device_mmap,
 };
 
 struct kvm_device *kvm_device_from_filp(struct file *filp)
 {
         if (filp->f_op != &kvm_device_fops)
                 return NULL;
 
         return filp->private_data;
 }
 
 static const 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(const 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)
 {
         const 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_ACCOUNT);
         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_no_destroy(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:
         case KVM_CAP_HALT_POLL:
                 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_KVM_GENERIC_DIRTYLOG_READ_PROTECT
         case KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2:
                 return KVM_DIRTY_LOG_MANUAL_CAPS;
 #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_NR_MEMSLOTS:
                 return KVM_USER_MEM_SLOTS;
         case KVM_CAP_DIRTY_LOG_RING:
 #if KVM_DIRTY_LOG_PAGE_OFFSET > 0
                 return KVM_DIRTY_RING_MAX_ENTRIES * sizeof(struct kvm_dirty_gfn);
 #else
                 return 0;
 #endif
         case KVM_CAP_BINARY_STATS_FD:
                 return 1;
         default:
                 break;
         }
         return kvm_vm_ioctl_check_extension(kvm, arg);
 }
 
 static int kvm_vm_ioctl_enable_dirty_log_ring(struct kvm *kvm, u32 size)
 {
         int r;
 
         if (!KVM_DIRTY_LOG_PAGE_OFFSET)
                 return -EINVAL;
 
         /* the size should be power of 2 */
         if (!size || (size & (size - 1)))
                 return -EINVAL;
 
         /* Should be bigger to keep the reserved entries, or a page */
         if (size < kvm_dirty_ring_get_rsvd_entries() *
             sizeof(struct kvm_dirty_gfn) || size < PAGE_SIZE)
                 return -EINVAL;
 
         if (size > KVM_DIRTY_RING_MAX_ENTRIES *
             sizeof(struct kvm_dirty_gfn))
                 return -E2BIG;
 
         /* We only allow it to set once */
         if (kvm->dirty_ring_size)
                 return -EINVAL;
 
         mutex_lock(&kvm->lock);
 
         if (kvm->created_vcpus) {
                 /* We don't allow to change this value after vcpu created */
                 r = -EINVAL;
         } else {
                 kvm->dirty_ring_size = size;
                 r = 0;
         }
 
         mutex_unlock(&kvm->lock);
         return r;
 }
 
 static int kvm_vm_ioctl_reset_dirty_pages(struct kvm *kvm)
 {
         int i;
         struct kvm_vcpu *vcpu;
         int cleared = 0;
 
         if (!kvm->dirty_ring_size)
                 return -EINVAL;
 
         mutex_lock(&kvm->slots_lock);
 
         kvm_for_each_vcpu(i, vcpu, kvm)
                 cleared += kvm_dirty_ring_reset(vcpu->kvm, &vcpu->dirty_ring);
 
         mutex_unlock(&kvm->slots_lock);
 
         if (cleared)
                 kvm_flush_remote_tlbs(kvm);
 
         return cleared;
 }
 
 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_PROTECT2: {
                 u64 allowed_options = KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE;
 
                 if (cap->args[0] & KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE)
                         allowed_options = KVM_DIRTY_LOG_MANUAL_CAPS;
 
                 if (cap->flags || (cap->args[0] & ~allowed_options))
                         return -EINVAL;
                 kvm->manual_dirty_log_protect = cap->args[0];
                 return 0;
         }
 #endif
         case KVM_CAP_HALT_POLL: {
                 if (cap->flags || cap->args[0] != (unsigned int)cap->args[0])
                         return -EINVAL;
 
                 kvm->max_halt_poll_ns = cap->args[0];
                 return 0;
         }
         case KVM_CAP_DIRTY_LOG_RING:
                 return kvm_vm_ioctl_enable_dirty_log_ring(kvm, cap->args[0]);
         default:
                 return kvm_vm_ioctl_enable_cap(kvm, cap);
         }
 }
 
 static ssize_t kvm_vm_stats_read(struct file *file, char __user *user_buffer,
                               size_t size, loff_t *offset)
 {
         struct kvm *kvm = file->private_data;
 
         return kvm_stats_read(kvm->stats_id, &kvm_vm_stats_header,
                                 &kvm_vm_stats_desc[0], &kvm->stat,
                                 sizeof(kvm->stat), user_buffer, size, offset);
 }
 
 static const struct file_operations kvm_vm_stats_fops = {
         .read = kvm_vm_stats_read,
         .llseek = noop_llseek,
 };
 
 static int kvm_vm_ioctl_get_stats_fd(struct kvm *kvm)
 {
         int fd;
         struct file *file;
 
         fd = get_unused_fd_flags(O_CLOEXEC);
         if (fd < 0)
                 return fd;
 
         file = anon_inode_getfile("kvm-vm-stats",
                         &kvm_vm_stats_fops, kvm, O_RDONLY);
         if (IS_ERR(file)) {
                 put_unused_fd(fd);
                 return PTR_ERR(file);
         }
         file->f_mode |= FMODE_PREAD;
         fd_install(fd, file);
 
         return fd;
 }
 
 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) {
                         urouting = argp;
                         entries = vmemdup_user(urouting->entries,
                                                array_size(sizeof(*entries),
                                                           routing.nr));
                         if (IS_ERR(entries)) {
                                 r = PTR_ERR(entries);
                                 goto out;
                         }
                 }
                 r = kvm_set_irq_routing(kvm, entries, routing.nr,
                                         routing.flags);
                 kvfree(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;
         case KVM_RESET_DIRTY_RINGS:
                 r = kvm_vm_ioctl_reset_dirty_pages(kvm);
                 break;
         case KVM_GET_STATS_FD:
                 r = kvm_vm_ioctl_get_stats_fd(kvm);
                 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;
         };
 };
 
 struct compat_kvm_clear_dirty_log {
         __u32 slot;
         __u32 num_pages;
         __u64 first_page;
         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) {
 #ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
         case KVM_CLEAR_DIRTY_LOG: {
                 struct compat_kvm_clear_dirty_log compat_log;
                 struct kvm_clear_dirty_log log;
 
                 if (copy_from_user(&compat_log, (void __user *)arg,
                                    sizeof(compat_log)))
                         return -EFAULT;
                 log.slot         = compat_log.slot;
                 log.num_pages    = compat_log.num_pages;
                 log.first_page   = compat_log.first_page;
                 log.padding2     = compat_log.padding2;
                 log.dirty_bitmap = compat_ptr(compat_log.dirty_bitmap);
 
                 r = kvm_vm_ioctl_clear_dirty_log(kvm, &log);
                 break;
         }
 #endif
         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),
 };
 
 bool file_is_kvm(struct file *file)
 {
         return file && file->f_op == &kvm_vm_fops;
 }
 EXPORT_SYMBOL_GPL(file_is_kvm);
 
 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;
 
         snprintf(kvm->stats_id, sizeof(kvm->stats_id),
                         "kvm-%d", task_pid_nr(current));
 
         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;
 }
 EXPORT_SYMBOL_GPL(kvm_io_bus_write);
 
 /* 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;
 }
 
 /* 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(struct_size(bus, range, bus->dev_count + 1),
                           GFP_KERNEL_ACCOUNT);
         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;
 }
 
 int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
                               struct kvm_io_device *dev)
 {
         int i, j;
         struct kvm_io_bus *new_bus, *bus;
 
         lockdep_assert_held(&kvm->slots_lock);
 
         bus = kvm_get_bus(kvm, bus_idx);
         if (!bus)
                 return 0;
 
         for (i = 0; i < bus->dev_count; i++) {
                 if (bus->range[i].dev == dev) {
                         break;
                 }
         }
 
         if (i == bus->dev_count)
                 return 0;
 
         new_bus = kmalloc(struct_size(bus, range, bus->dev_count - 1),
                           GFP_KERNEL_ACCOUNT);
         if (new_bus) {
                 memcpy(new_bus, bus, struct_size(bus, range, i));
                 new_bus->dev_count--;
                 memcpy(new_bus->range + i, bus->range + i + 1,
                                 flex_array_size(new_bus, range, new_bus->dev_count - i));
         }
 
         rcu_assign_pointer(kvm->buses[bus_idx], new_bus);
         synchronize_srcu_expedited(&kvm->srcu);
 
         /* Destroy the old bus _after_ installing the (null) bus. */
         if (!new_bus) {
                 pr_err("kvm: failed to shrink bus, removing it completely\n");
                 for (j = 0; j < bus->dev_count; j++) {
                         if (j == i)
                                 continue;
                         kvm_iodevice_destructor(bus->range[j].dev);
                 }
         }
 
         kfree(bus);
         return new_bus ? 0 : -ENOMEM;
 }
 
 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,
                     kvm_stats_debugfs_mode(stat_data->desc) & 0222
                     ? set : NULL,
                     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 kvm_get_stat_per_vm(struct kvm *kvm, size_t offset, u64 *val)
 {
         *val = *(u64 *)((void *)(&kvm->stat) + offset);
 
         return 0;
 }
 
 static int kvm_clear_stat_per_vm(struct kvm *kvm, size_t offset)
 {
         *(u64 *)((void *)(&kvm->stat) + offset) = 0;
 
         return 0;
 }
 
 static int kvm_get_stat_per_vcpu(struct kvm *kvm, size_t offset, u64 *val)
 {
         int i;
         struct kvm_vcpu *vcpu;
 
         *val = 0;
 
         kvm_for_each_vcpu(i, vcpu, kvm)
                 *val += *(u64 *)((void *)(&vcpu->stat) + offset);
 
         return 0;
 }
 
 static int kvm_clear_stat_per_vcpu(struct kvm *kvm, size_t offset)
 {
         int i;
         struct kvm_vcpu *vcpu;
 
         kvm_for_each_vcpu(i, vcpu, kvm)
                 *(u64 *)((void *)(&vcpu->stat) + offset) = 0;
 
         return 0;
 }
 
 static int kvm_stat_data_get(void *data, u64 *val)
 {
         int r = -EFAULT;
         struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
 
         switch (stat_data->kind) {
         case KVM_STAT_VM:
                 r = kvm_get_stat_per_vm(stat_data->kvm,
                                         stat_data->desc->desc.offset, val);
                 break;
         case KVM_STAT_VCPU:
                 r = kvm_get_stat_per_vcpu(stat_data->kvm,
                                           stat_data->desc->desc.offset, val);
                 break;
         }
 
         return r;
 }
 
 static int kvm_stat_data_clear(void *data, u64 val)
 {
         int r = -EFAULT;
         struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
 
         if (val)
                 return -EINVAL;
 
         switch (stat_data->kind) {
         case KVM_STAT_VM:
                 r = kvm_clear_stat_per_vm(stat_data->kvm,
                                           stat_data->desc->desc.offset);
                 break;
         case KVM_STAT_VCPU:
                 r = kvm_clear_stat_per_vcpu(stat_data->kvm,
                                             stat_data->desc->desc.offset);
                 break;
         }
 
         return r;
 }
 
 static int kvm_stat_data_open(struct inode *inode, struct file *file)
 {
         __simple_attr_check_format("%llu\n", 0ull);
         return kvm_debugfs_open(inode, file, kvm_stat_data_get,
                                 kvm_stat_data_clear, "%llu\n");
 }
 
 static const struct file_operations stat_fops_per_vm = {
         .owner = THIS_MODULE,
         .open = kvm_stat_data_open,
         .release = kvm_debugfs_release,
         .read = simple_attr_read,
         .write = simple_attr_write,
         .llseek = no_llseek,
 };
 
 static int vm_stat_get(void *_offset, u64 *val)
 {
         unsigned offset = (long)_offset;
         struct kvm *kvm;
         u64 tmp_val;
 
         *val = 0;
         mutex_lock(&kvm_lock);
         list_for_each_entry(kvm, &vm_list, vm_list) {
                 kvm_get_stat_per_vm(kvm, offset, &tmp_val);
                 *val += tmp_val;
         }
         mutex_unlock(&kvm_lock);
         return 0;
 }
 
 static int vm_stat_clear(void *_offset, u64 val)
 {
         unsigned offset = (long)_offset;
         struct kvm *kvm;
 
         if (val)
                 return -EINVAL;
 
         mutex_lock(&kvm_lock);
         list_for_each_entry(kvm, &vm_list, vm_list) {
                 kvm_clear_stat_per_vm(kvm, offset);
         }
         mutex_unlock(&kvm_lock);
 
         return 0;
 }
 
 DEFINE_SIMPLE_ATTRIBUTE(vm_stat_fops, vm_stat_get, vm_stat_clear, "%llu\n");
 DEFINE_SIMPLE_ATTRIBUTE(vm_stat_readonly_fops, vm_stat_get, NULL, "%llu\n");
 
 static int vcpu_stat_get(void *_offset, u64 *val)
 {
         unsigned offset = (long)_offset;
         struct kvm *kvm;
         u64 tmp_val;
 
         *val = 0;
         mutex_lock(&kvm_lock);
         list_for_each_entry(kvm, &vm_list, vm_list) {
                 kvm_get_stat_per_vcpu(kvm, offset, &tmp_val);
                 *val += tmp_val;
         }
         mutex_unlock(&kvm_lock);
         return 0;
 }
 
 static int vcpu_stat_clear(void *_offset, u64 val)
 {
         unsigned offset = (long)_offset;
         struct kvm *kvm;
 
         if (val)
                 return -EINVAL;
 
         mutex_lock(&kvm_lock);
         list_for_each_entry(kvm, &vm_list, vm_list) {
                 kvm_clear_stat_per_vcpu(kvm, offset);
         }
         mutex_unlock(&kvm_lock);
 
         return 0;
 }
 
 DEFINE_SIMPLE_ATTRIBUTE(vcpu_stat_fops, vcpu_stat_get, vcpu_stat_clear,
                         "%llu\n");
 DEFINE_SIMPLE_ATTRIBUTE(vcpu_stat_readonly_fops, vcpu_stat_get, NULL, "%llu\n");
 
 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;
 
         mutex_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;
         mutex_unlock(&kvm_lock);
 
         env = kzalloc(sizeof(*env), GFP_KERNEL_ACCOUNT);
         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 (kvm->debugfs_dentry) {
                 char *tmp, *p = kmalloc(PATH_MAX, GFP_KERNEL_ACCOUNT);
 
                 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)
 {
         const struct file_operations *fops;
         const struct _kvm_stats_desc *pdesc;
         int i;
 
         kvm_debugfs_dir = debugfs_create_dir("kvm", NULL);
 
         for (i = 0; i < kvm_vm_stats_header.num_desc; ++i) {
                 pdesc = &kvm_vm_stats_desc[i];
                 if (kvm_stats_debugfs_mode(pdesc) & 0222)
                         fops = &vm_stat_fops;
                 else
                         fops = &vm_stat_readonly_fops;
                 debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
                                 kvm_debugfs_dir,
                                 (void *)(long)pdesc->desc.offset, fops);
         }
 
         for (i = 0; i < kvm_vcpu_stats_header.num_desc; ++i) {
                 pdesc = &kvm_vcpu_stats_desc[i];
                 if (kvm_stats_debugfs_mode(pdesc) & 0222)
                         fops = &vcpu_stat_fops;
                 else
                         fops = &vcpu_stat_readonly_fops;
                 debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
                                 kvm_debugfs_dir,
                                 (void *)(long)pdesc->desc.offset, fops);
         }
 }
 
 static int kvm_suspend(void)
 {
         if (kvm_usage_count)
                 hardware_disable_nolock(NULL);
         return 0;
 }
 
 static void kvm_resume(void)
 {
         if (kvm_usage_count) {
 #ifdef CONFIG_LOCKDEP
                 WARN_ON(lockdep_is_held(&kvm_count_lock));
 #endif
                 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);
 
         WRITE_ONCE(vcpu->preempted, false);
         WRITE_ONCE(vcpu->ready, false);
 
         __this_cpu_write(kvm_running_vcpu, vcpu);
         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->on_rq) {
                 WRITE_ONCE(vcpu->preempted, true);
                 WRITE_ONCE(vcpu->ready, true);
         }
         kvm_arch_vcpu_put(vcpu);
         __this_cpu_write(kvm_running_vcpu, NULL);
 }
 
 /**
  * kvm_get_running_vcpu - get the vcpu running on the current CPU.
  *
  * We can disable preemption locally around accessing the per-CPU variable,
  * and use the resolved vcpu pointer after enabling preemption again,
  * because even if the current thread is migrated to another CPU, reading
  * the per-CPU value later will give us the same value as we update the
  * per-CPU variable in the preempt notifier handlers.
  */
 struct kvm_vcpu *kvm_get_running_vcpu(void)
 {
         struct kvm_vcpu *vcpu;
 
         preempt_disable();
         vcpu = __this_cpu_read(kvm_running_vcpu);
         preempt_enable();
 
         return vcpu;
 }
 EXPORT_SYMBOL_GPL(kvm_get_running_vcpu);
 
 /**
  * kvm_get_running_vcpus - get the per-CPU array of currently running vcpus.
  */
 struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void)
 {
         return &kvm_running_vcpu;
 }
 
 struct kvm_cpu_compat_check {
         void *opaque;
         int *ret;
 };
 
 static void check_processor_compat(void *data)
 {
         struct kvm_cpu_compat_check *c = data;
 
         *c->ret = kvm_arch_check_processor_compat(c->opaque);
 }
 
 int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
                   struct module *module)
 {
         struct kvm_cpu_compat_check c;
         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(opaque);
         if (r < 0)
                 goto out_free_1;
 
         c.ret = &r;
         c.opaque = opaque;
         for_each_online_cpu(cpu) {
                 smp_call_function_single(cpu, check_processor_compat, &c, 1);
                 if (r < 0)
                         goto out_free_2;
         }
 
         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),
                                            offsetofend(struct kvm_vcpu, stats_id)
                                            - offsetof(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:
         kvm_arch_hardware_unsetup();
 out_free_1:
         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);
 
 struct kvm_vm_worker_thread_context {
         struct kvm *kvm;
         struct task_struct *parent;
         struct completion init_done;
         kvm_vm_thread_fn_t thread_fn;
         uintptr_t data;
         int err;
 };
 
 static int kvm_vm_worker_thread(void *context)
 {
         /*
          * The init_context is allocated on the stack of the parent thread, so
          * we have to locally copy anything that is needed beyond initialization
          */
         struct kvm_vm_worker_thread_context *init_context = context;
         struct kvm *kvm = init_context->kvm;
         kvm_vm_thread_fn_t thread_fn = init_context->thread_fn;
         uintptr_t data = init_context->data;
         int err;
 
         err = kthread_park(current);
         /* kthread_park(current) is never supposed to return an error */
         WARN_ON(err != 0);
         if (err)
                 goto init_complete;
 
         err = cgroup_attach_task_all(init_context->parent, current);
         if (err) {
                 kvm_err("%s: cgroup_attach_task_all failed with err %d\n",
                         __func__, err);
                 goto init_complete;
         }
 
         set_user_nice(current, task_nice(init_context->parent));
 
 init_complete:
         init_context->err = err;
         complete(&init_context->init_done);
         init_context = NULL;
 
         if (err)
                 return err;
 
         /* Wait to be woken up by the spawner before proceeding. */
         kthread_parkme();
 
         if (!kthread_should_stop())
                 err = thread_fn(kvm, data);
 
         return err;
 }
 
 int kvm_vm_create_worker_thread(struct kvm *kvm, kvm_vm_thread_fn_t thread_fn,
                                 uintptr_t data, const char *name,
                                 struct task_struct **thread_ptr)
 {
         struct kvm_vm_worker_thread_context init_context = {};
         struct task_struct *thread;
 
         *thread_ptr = NULL;
         init_context.kvm = kvm;
         init_context.parent = current;
         init_context.thread_fn = thread_fn;
         init_context.data = data;
         init_completion(&init_context.init_done);
 
         thread = kthread_run(kvm_vm_worker_thread, &init_context,
                              "%s-%d", name, task_pid_nr(current));
         if (IS_ERR(thread))
                 return PTR_ERR(thread);
 
         /* kthread_run is never supposed to return NULL */
         WARN_ON(thread == NULL);
 
         wait_for_completion(&init_context.init_done);
 
         if (!init_context.err)
                 *thread_ptr = thread;
 
         return init_context.err;
 }