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

   // SPDX-License-Identifier: GPL-2.0-only
   /*
    * Kernel-based Virtual Machine (KVM) Hypervisor
    *
    * 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 "kvm_mm.h"
  #include "vfio.h"
  
  #include <trace/events/ipi.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_DESCRIPTION("Kernel-based Virtual Machine (KVM) Hypervisor");
  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 halves per-vcpu halt_poll_ns. */
  unsigned int halt_poll_ns_shrink = 2;
  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);
 LIST_HEAD(vm_list);
 
 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);
 
 static struct dentry *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);
 
 #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;
 
 static DEFINE_PER_CPU(cpumask_var_t, cpu_kick_mask);
 
 __weak void kvm_arch_guest_memory_reclaimed(struct kvm *kvm)
 {
 }
 
 bool kvm_is_zone_device_page(struct page *page)
 {
         /*
          * 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 (WARN_ON_ONCE(!page_count(page)))
                 return false;
 
         return is_zone_device_page(page);
 }
 
 /*
  * Returns a 'struct page' if the pfn is "valid" and backed by a refcounted
  * page, NULL otherwise.  Note, the list of refcounted PG_reserved page types
  * is likely incomplete, it has been compiled purely through people wanting to
  * back guest with a certain type of memory and encountering issues.
  */
 struct page *kvm_pfn_to_refcounted_page(kvm_pfn_t pfn)
 {
         struct page *page;
 
         if (!pfn_valid(pfn))
                 return NULL;
 
         page = pfn_to_page(pfn);
         if (!PageReserved(page))
                 return page;
 
         /* The ZERO_PAGE(s) is marked PG_reserved, but is refcounted. */
         if (is_zero_pfn(pfn))
                 return page;
 
         /*
          * ZONE_DEVICE pages currently set PG_reserved, but from a refcounting
          * perspective they are "normal" pages, albeit with slightly different
          * usage rules.
          */
         if (kvm_is_zone_device_page(page))
                 return page;
 
         return NULL;
 }
 
 /*
  * 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_kick(void *_completed)
 {
 }
 
 static inline bool kvm_kick_many_cpus(struct cpumask *cpus, bool wait)
 {
         if (cpumask_empty(cpus))
                 return false;
 
         smp_call_function_many(cpus, ack_kick, NULL, wait);
         return true;
 }
 
 static void kvm_make_vcpu_request(struct kvm_vcpu *vcpu, unsigned int req,
                                   struct cpumask *tmp, int current_cpu)
 {
         int cpu;
 
         if (likely(!(req & KVM_REQUEST_NO_ACTION)))
                 __kvm_make_request(req, vcpu);
 
         if (!(req & KVM_REQUEST_NO_WAKEUP) && kvm_vcpu_wake_up(vcpu))
                 return;
 
         /*
          * Note, the vCPU could get migrated to a different pCPU at any point
          * after kvm_request_needs_ipi(), which could result in sending an IPI
          * to the previous pCPU.  But, that's OK because the purpose of the IPI
          * is to ensure the vCPU returns to OUTSIDE_GUEST_MODE, which is
          * satisfied if the vCPU migrates. Entering READING_SHADOW_PAGE_TABLES
          * after this point is also OK, as the requirement is only that KVM wait
          * for vCPUs that were reading SPTEs _before_ any changes were
          * finalized. See kvm_vcpu_kick() for more details on handling requests.
          */
         if (kvm_request_needs_ipi(vcpu, req)) {
                 cpu = READ_ONCE(vcpu->cpu);
                 if (cpu != -1 && cpu != current_cpu)
                         __cpumask_set_cpu(cpu, tmp);
         }
 }
 
 bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
                                  unsigned long *vcpu_bitmap)
 {
         struct kvm_vcpu *vcpu;
         struct cpumask *cpus;
         int i, me;
         bool called;
 
         me = get_cpu();
 
         cpus = this_cpu_cpumask_var_ptr(cpu_kick_mask);
         cpumask_clear(cpus);
 
         for_each_set_bit(i, vcpu_bitmap, KVM_MAX_VCPUS) {
                 vcpu = kvm_get_vcpu(kvm, i);
                 if (!vcpu)
                         continue;
                 kvm_make_vcpu_request(vcpu, req, cpus, me);
         }
 
         called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT));
         put_cpu();
 
         return called;
 }
 
 bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
 {
         struct kvm_vcpu *vcpu;
         struct cpumask *cpus;
         unsigned long i;
         bool called;
         int me;
 
         me = get_cpu();
 
         cpus = this_cpu_cpumask_var_ptr(cpu_kick_mask);
         cpumask_clear(cpus);
 
         kvm_for_each_vcpu(i, vcpu, kvm)
                 kvm_make_vcpu_request(vcpu, req, cpus, me);
 
         called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT));
         put_cpu();
 
         return called;
 }
 EXPORT_SYMBOL_GPL(kvm_make_all_cpus_request);
 
 void kvm_flush_remote_tlbs(struct kvm *kvm)
 {
         ++kvm->stat.generic.remote_tlb_flush_requests;
 
         /*
          * 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_tlbs(kvm)
             || kvm_make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH))
                 ++kvm->stat.generic.remote_tlb_flush;
 }
 EXPORT_SYMBOL_GPL(kvm_flush_remote_tlbs);
 
 void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, u64 nr_pages)
 {
         if (!kvm_arch_flush_remote_tlbs_range(kvm, gfn, nr_pages))
                 return;
 
         /*
          * Fall back to a flushing entire TLBs if the architecture range-based
          * TLB invalidation is unsupported or can't be performed for whatever
          * reason.
          */
         kvm_flush_remote_tlbs(kvm);
 }
 
 void kvm_flush_remote_tlbs_memslot(struct kvm *kvm,
                                    const struct kvm_memory_slot *memslot)
 {
         /*
          * All current use cases for flushing the TLBs for a specific memslot
          * are related to dirty logging, and many do the TLB flush out of
          * mmu_lock. The interaction between the various operations on memslot
          * must be serialized by slots_locks to ensure the TLB flush from one
          * operation is observed by any other operation on the same memslot.
          */
         lockdep_assert_held(&kvm->slots_lock);
         kvm_flush_remote_tlbs_range(kvm, memslot->base_gfn, memslot->npages);
 }
 
 static void kvm_flush_shadow_all(struct kvm *kvm)
 {
         kvm_arch_flush_shadow_all(kvm);
         kvm_arch_guest_memory_reclaimed(kvm);
 }
 
 #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)
 {
         void *page;
 
         gfp_flags |= mc->gfp_zero;
 
         if (mc->kmem_cache)
                 return kmem_cache_alloc(mc->kmem_cache, gfp_flags);
 
         page = (void *)__get_free_page(gfp_flags);
         if (page && mc->init_value)
                 memset64(page, mc->init_value, PAGE_SIZE / sizeof(u64));
         return page;
 }
 
 int __kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int capacity, int min)
 {
         gfp_t gfp = mc->gfp_custom ? mc->gfp_custom : GFP_KERNEL_ACCOUNT;
         void *obj;
 
         if (mc->nobjs >= min)
                 return 0;
 
         if (unlikely(!mc->objects)) {
                 if (WARN_ON_ONCE(!capacity))
                         return -EIO;
 
                 /*
                  * Custom init values can be used only for page allocations,
                  * and obviously conflict with __GFP_ZERO.
                  */
                 if (WARN_ON_ONCE(mc->init_value && (mc->kmem_cache || mc->gfp_zero)))
                         return -EIO;
 
                 mc->objects = kvmalloc_array(capacity, sizeof(void *), gfp);
                 if (!mc->objects)
                         return -ENOMEM;
 
                 mc->capacity = capacity;
         }
 
         /* It is illegal to request a different capacity across topups. */
         if (WARN_ON_ONCE(mc->capacity != capacity))
                 return -EIO;
 
         while (mc->nobjs < mc->capacity) {
                 obj = mmu_memory_cache_alloc_obj(mc, gfp);
                 if (!obj)
                         return mc->nobjs >= min ? 0 : -ENOMEM;
                 mc->objects[mc->nobjs++] = obj;
         }
         return 0;
 }
 
 int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min)
 {
         return __kvm_mmu_topup_memory_cache(mc, KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE, min);
 }
 
 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]);
         }
 
         kvfree(mc->objects);
 
         mc->objects = NULL;
         mc->capacity = 0;
 }
 
 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;
 #ifndef __KVM_HAVE_ARCH_WQP
         rcuwait_init(&vcpu->wait);
 #endif
         kvm_async_pf_vcpu_init(vcpu);
 
         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);
         vcpu->last_used_slot = NULL;
 
         /* 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);
 }
 
 static void kvm_vcpu_destroy(struct kvm_vcpu *vcpu)
 {
         kvm_arch_vcpu_destroy(vcpu);
         kvm_dirty_ring_free(&vcpu->dirty_ring);
 
         /*
          * 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);
 }
 
 void kvm_destroy_vcpus(struct kvm *kvm)
 {
         unsigned long i;
         struct kvm_vcpu *vcpu;
 
         kvm_for_each_vcpu(i, vcpu, kvm) {
                 kvm_vcpu_destroy(vcpu);
                 xa_erase(&kvm->vcpu_array, i);
         }
 
         atomic_set(&kvm->online_vcpus, 0);
 }
 EXPORT_SYMBOL_GPL(kvm_destroy_vcpus);
 
 #ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER
 static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn)
 {
         return container_of(mn, struct kvm, mmu_notifier);
 }
 
 typedef bool (*gfn_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range);
 
 typedef void (*on_lock_fn_t)(struct kvm *kvm);
 
 struct kvm_mmu_notifier_range {
         /*
          * 64-bit addresses, as KVM notifiers can operate on host virtual
          * addresses (unsigned long) and guest physical addresses (64-bit).
          */
         u64 start;
         u64 end;
         union kvm_mmu_notifier_arg arg;
         gfn_handler_t handler;
         on_lock_fn_t on_lock;
         bool flush_on_ret;
         bool may_block;
 };
 
 /*
  * The inner-most helper returns a tuple containing the return value from the
  * arch- and action-specific handler, plus a flag indicating whether or not at
  * least one memslot was found, i.e. if the handler found guest memory.
  *
  * Note, most notifiers are averse to booleans, so even though KVM tracks the
  * return from arch code as a bool, outer helpers will cast it to an int. :-(
  */
 typedef struct kvm_mmu_notifier_return {
         bool ret;
         bool found_memslot;
 } kvm_mn_ret_t;
 
 /*
  * 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)
 
 /* Iterate over each memslot intersecting [start, last] (inclusive) range */
 #define kvm_for_each_memslot_in_hva_range(node, slots, start, last)          \
         for (node = interval_tree_iter_first(&slots->hva_tree, start, last); \
              node;                                                           \
              node = interval_tree_iter_next(node, start, last))      \
 
 static __always_inline kvm_mn_ret_t __kvm_handle_hva_range(struct kvm *kvm,
                                                            const struct kvm_mmu_notifier_range *range)
 {
         struct kvm_mmu_notifier_return r = {
                 .ret = false,
                 .found_memslot = false,
         };
         struct kvm_gfn_range gfn_range;
         struct kvm_memory_slot *slot;
         struct kvm_memslots *slots;
         int i, idx;
 
         if (WARN_ON_ONCE(range->end <= range->start))
                 return r;
 
         /* 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 r;
 
         idx = srcu_read_lock(&kvm->srcu);
 
         for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
                 struct interval_tree_node *node;
 
                 slots = __kvm_memslots(kvm, i);
                 kvm_for_each_memslot_in_hva_range(node, slots,
                                                   range->start, range->end - 1) {
                         unsigned long hva_start, hva_end;
 
                         slot = container_of(node, struct kvm_memory_slot, hva_node[slots->node_idx]);
                         hva_start = max_t(unsigned long, range->start, slot->userspace_addr);
                         hva_end = min_t(unsigned long, range->end,
                                         slot->userspace_addr + (slot->npages << PAGE_SHIFT));
 
                         /*
                          * 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.arg = range->arg;
                         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 (!r.found_memslot) {
                                 r.found_memslot = true;
                                 KVM_MMU_LOCK(kvm);
                                 if (!IS_KVM_NULL_FN(range->on_lock))
                                         range->on_lock(kvm);
 
                                 if (IS_KVM_NULL_FN(range->handler))
                                         goto mmu_unlock;
                         }
                         r.ret |= range->handler(kvm, &gfn_range);
                 }
         }
 
         if (range->flush_on_ret && r.ret)
                 kvm_flush_remote_tlbs(kvm);
 
 mmu_unlock:
         if (r.found_memslot)
                 KVM_MMU_UNLOCK(kvm);
 
         srcu_read_unlock(&kvm->srcu, idx);
 
         return r;
 }
 
 static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn,
                                                 unsigned long start,
                                                 unsigned long end,
                                                 gfn_handler_t handler)
 {
         struct kvm *kvm = mmu_notifier_to_kvm(mn);
         const struct kvm_mmu_notifier_range range = {
                 .start          = start,
                 .end            = end,
                 .handler        = handler,
                 .on_lock        = (void *)kvm_null_fn,
                 .flush_on_ret   = true,
                 .may_block      = false,
         };
 
         return __kvm_handle_hva_range(kvm, &range).ret;
 }
 
 static __always_inline int kvm_handle_hva_range_no_flush(struct mmu_notifier *mn,
                                                          unsigned long start,
                                                          unsigned long end,
                                                          gfn_handler_t handler)
 {
         struct kvm *kvm = mmu_notifier_to_kvm(mn);
         const struct kvm_mmu_notifier_range range = {
                 .start          = start,
                 .end            = end,
                 .handler        = handler,
                 .on_lock        = (void *)kvm_null_fn,
                 .flush_on_ret   = false,
                 .may_block      = false,
         };
 
         return __kvm_handle_hva_range(kvm, &range).ret;
 }
 
 void kvm_mmu_invalidate_begin(struct kvm *kvm)
 {
         lockdep_assert_held_write(&kvm->mmu_lock);
         /*
          * The count increase must become visible at unlock time as no
          * spte can be established without taking the mmu_lock and
          * count is also read inside the mmu_lock critical section.
          */
         kvm->mmu_invalidate_in_progress++;
 
         if (likely(kvm->mmu_invalidate_in_progress == 1)) {
                 kvm->mmu_invalidate_range_start = INVALID_GPA;
                 kvm->mmu_invalidate_range_end = INVALID_GPA;
         }
 }
 
 void kvm_mmu_invalidate_range_add(struct kvm *kvm, gfn_t start, gfn_t end)
 {
         lockdep_assert_held_write(&kvm->mmu_lock);
 
         WARN_ON_ONCE(!kvm->mmu_invalidate_in_progress);
 
         if (likely(kvm->mmu_invalidate_range_start == INVALID_GPA)) {
                 kvm->mmu_invalidate_range_start = start;
                 kvm->mmu_invalidate_range_end = end;
         } else {
                 /*
                  * Fully tracking multiple concurrent ranges has diminishing
                  * 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_invalidate_range_start =
                         min(kvm->mmu_invalidate_range_start, start);
                 kvm->mmu_invalidate_range_end =
                         max(kvm->mmu_invalidate_range_end, end);
         }
 }
 
 bool kvm_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
 {
         kvm_mmu_invalidate_range_add(kvm, range->start, range->end);
         return kvm_unmap_gfn_range(kvm, range);
 }
 
 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_mmu_notifier_range hva_range = {
                 .start          = range->start,
                 .end            = range->end,
                 .handler        = kvm_mmu_unmap_gfn_range,
                 .on_lock        = kvm_mmu_invalidate_begin,
                 .flush_on_ret   = true,
                 .may_block      = mmu_notifier_range_blockable(range),
         };
 
         trace_kvm_unmap_hva_range(range->start, range->end);
 
         /*
          * Prevent memslot modification between range_start() and range_end()
          * so that conditionally locking provides the same result in both
          * functions.  Without that guarantee, the mmu_invalidate_in_progress
          * adjustments will be imbalanced.
          *
          * Pairs with the decrement in range_end().
          */
         spin_lock(&kvm->mn_invalidate_lock);
         kvm->mn_active_invalidate_count++;
         spin_unlock(&kvm->mn_invalidate_lock);
 
         /*
          * Invalidate pfn caches _before_ invalidating the secondary MMUs, i.e.
          * before acquiring mmu_lock, to avoid holding mmu_lock while acquiring
          * each cache's lock.  There are relatively few caches in existence at
          * any given time, and the caches themselves can check for hva overlap,
          * i.e. don't need to rely on memslot overlap checks for performance.
          * Because this runs without holding mmu_lock, the pfn caches must use
          * mn_active_invalidate_count (see above) instead of
          * mmu_invalidate_in_progress.
          */
         gfn_to_pfn_cache_invalidate_start(kvm, range->start, range->end);
 
         /*
          * If one or more memslots were found and thus zapped, notify arch code
          * that guest memory has been reclaimed.  This needs to be done *after*
          * dropping mmu_lock, as x86's reclaim path is slooooow.
          */
         if (__kvm_handle_hva_range(kvm, &hva_range).found_memslot)
                 kvm_arch_guest_memory_reclaimed(kvm);
 
         return 0;
 }
 
 void kvm_mmu_invalidate_end(struct kvm *kvm)
 {
         lockdep_assert_held_write(&kvm->mmu_lock);
 
         /*
          * This sequence increase will notify the kvm page fault that
          * the page that is going to be mapped in the spte could have
          * been freed.
          */
         kvm->mmu_invalidate_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_invalidate_retry().
          */
         kvm->mmu_invalidate_in_progress--;
         KVM_BUG_ON(kvm->mmu_invalidate_in_progress < 0, kvm);
 
         /*
          * Assert that at least one range was added between start() and end().
          * Not adding a range isn't fatal, but it is a KVM bug.
          */
         WARN_ON_ONCE(kvm->mmu_invalidate_range_start == INVALID_GPA);
 }
 
 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_mmu_notifier_range hva_range = {
                 .start          = range->start,
                 .end            = range->end,
                 .handler        = (void *)kvm_null_fn,
                 .on_lock        = kvm_mmu_invalidate_end,
                 .flush_on_ret   = false,
                 .may_block      = mmu_notifier_range_blockable(range),
         };
         bool wake;
 
         __kvm_handle_hva_range(kvm, &hva_range);
 
         /* Pairs with the increment in range_start(). */
         spin_lock(&kvm->mn_invalidate_lock);
         if (!WARN_ON_ONCE(!kvm->mn_active_invalidate_count))
                 --kvm->mn_active_invalidate_count;
         wake = !kvm->mn_active_invalidate_count;
         spin_unlock(&kvm->mn_invalidate_lock);
 
         /*
          * There can only be one waiter, since the wait happens under
          * slots_lock.
          */
         if (wake)
                 rcuwait_wake_up(&kvm->mn_memslots_update_rcuwait);
 }
 
 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, 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_flush_shadow_all(kvm);
         srcu_read_unlock(&kvm->srcu, idx);
 }
 
 static const struct mmu_notifier_ops kvm_mmu_notifier_ops = {
         .invalidate_range_start = kvm_mmu_notifier_invalidate_range_start,
         .invalidate_range_end   = kvm_mmu_notifier_invalidate_range_end,
         .clear_flush_young      = kvm_mmu_notifier_clear_flush_young,
         .clear_young            = kvm_mmu_notifier_clear_young,
         .test_young             = kvm_mmu_notifier_test_young,
         .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_KVM_GENERIC_MMU_NOTIFIER */
 
 static int kvm_init_mmu_notifier(struct kvm *kvm)
 {
         return 0;
 }
 
 #endif /* CONFIG_KVM_GENERIC_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 void kvm_destroy_dirty_bitmap(struct kvm_memory_slot *memslot)
 {
         if (!memslot->dirty_bitmap)
                 return;
 
         vfree(memslot->dirty_bitmap);
         memslot->dirty_bitmap = NULL;
 }
 
 /* This does not remove the slot from struct kvm_memslots data structures */
 static void kvm_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot)
 {
         if (slot->flags & KVM_MEM_GUEST_MEMFD)
                 kvm_gmem_unbind(slot);
 
         kvm_destroy_dirty_bitmap(slot);
 
         kvm_arch_free_memslot(kvm, slot);
 
         kfree(slot);
 }
 
 static void kvm_free_memslots(struct kvm *kvm, struct kvm_memslots *slots)
 {
         struct hlist_node *idnode;
         struct kvm_memory_slot *memslot;
         int bkt;
 
         /*
          * The same memslot objects live in both active and inactive sets,
          * arbitrarily free using index '1' so the second invocation of this
          * function isn't operating over a structure with dangling pointers
          * (even though this function isn't actually touching them).
          */
         if (!slots->node_idx)
                 return;
 
         hash_for_each_safe(slots->id_hash, bkt, idnode, memslot, id_node[1])
                 kvm_free_memslot(kvm, memslot);
 }
 
 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 (IS_ERR(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, const char *fdname)
 {
         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, ret = -ENOMEM;
         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-%s", task_pid_nr(current), fdname);
         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)
                 goto out_err;
 
         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)
                         goto out_err;
 
                 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)
                         goto out_err;
 
                 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);
         }
 
         kvm_arch_create_vm_debugfs(kvm);
         return 0;
 out_err:
         kvm_destroy_vm_debugfs(kvm);
         return ret;
 }
 
 /*
  * 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)
 {
 }
 
 /*
  * Called after per-vm debugfs created.  When called kvm->debugfs_dentry should
  * be setup already, so we can create arch-specific debugfs entries under it.
  * Cleanup should be automatic done in kvm_destroy_vm_debugfs() recursively, so
  * a per-arch destroy interface is not needed.
  */
 void __weak kvm_arch_create_vm_debugfs(struct kvm *kvm)
 {
 }
 
 static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
 {
         struct kvm *kvm = kvm_arch_alloc_vm();
         struct kvm_memslots *slots;
         int r, i, j;
 
         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);
         spin_lock_init(&kvm->mn_invalidate_lock);
         rcuwait_init(&kvm->mn_memslots_update_rcuwait);
         xa_init(&kvm->vcpu_array);
 #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
         xa_init(&kvm->mem_attr_array);
 #endif
 
         INIT_LIST_HEAD(&kvm->gpc_list);
         spin_lock_init(&kvm->gpc_lock);
 
         INIT_LIST_HEAD(&kvm->devices);
         kvm->max_vcpus = KVM_MAX_VCPUS;
 
         BUILD_BUG_ON(KVM_MEM_SLOTS_NUM > SHRT_MAX);
 
         /*
          * Force subsequent debugfs file creations to fail if the VM directory
          * is not created (by kvm_create_vm_debugfs()).
          */
         kvm->debugfs_dentry = ERR_PTR(-ENOENT);
 
         snprintf(kvm->stats_id, sizeof(kvm->stats_id), "kvm-%d",
                  task_pid_nr(current));
 
         r = -ENOMEM;
         if (init_srcu_struct(&kvm->srcu))
                 goto out_err_no_srcu;
         if (init_srcu_struct(&kvm->irq_srcu))
                 goto out_err_no_irq_srcu;
 
         r = kvm_init_irq_routing(kvm);
         if (r)
                 goto out_err_no_irq_routing;
 
         refcount_set(&kvm->users_count, 1);
 
         for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
                 for (j = 0; j < 2; j++) {
                         slots = &kvm->__memslots[i][j];
 
                         atomic_long_set(&slots->last_used_slot, (unsigned long)NULL);
                         slots->hva_tree = RB_ROOT_CACHED;
                         slots->gfn_tree = RB_ROOT;
                         hash_init(slots->id_hash);
                         slots->node_idx = j;
 
                         /* Generations must be different for each address space. */
                         slots->generation = i;
                 }
 
                 rcu_assign_pointer(kvm->memslots[i], &kvm->__memslots[i][0]);
         }
 
         r = -ENOMEM;
         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;
         }
 
         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_IRQCHIP
         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_coalesced_mmio_init(kvm);
         if (r < 0)
                 goto out_no_coalesced_mmio;
 
         r = kvm_create_vm_debugfs(kvm, fdname);
         if (r)
                 goto out_err_no_debugfs;
 
         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:
         kvm_destroy_vm_debugfs(kvm);
 out_err_no_debugfs:
         kvm_coalesced_mmio_free(kvm);
 out_no_coalesced_mmio:
 #ifdef CONFIG_KVM_GENERIC_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));
         kvm_free_irq_routing(kvm);
 out_err_no_irq_routing:
         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.
          *
          * The device list is generally managed as an rculist, but list_del()
          * is used intentionally here. If a bug in KVM introduced a reader that
          * was not backed by a reference on the kvm struct, the hope is that
          * it'd consume the poisoned forward pointer instead of suffering a
          * use-after-free, even though this cannot be guaranteed.
          */
         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);
 #ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER
         mmu_notifier_unregister(&kvm->mmu_notifier, kvm->mm);
         /*
          * At this point, pending calls to invalidate_range_start()
          * have completed but no more MMU notifiers will run, so
          * mn_active_invalidate_count may remain unbalanced.
          * No threads can be waiting in kvm_swap_active_memslots() as the
          * last reference on KVM has been dropped, but freeing
          * memslots would deadlock without this manual intervention.
          *
          * If the count isn't unbalanced, i.e. KVM did NOT unregister its MMU
          * notifier between a start() and end(), then there shouldn't be any
          * in-progress invalidations.
          */
         WARN_ON(rcuwait_active(&kvm->mn_memslots_update_rcuwait));
         if (kvm->mn_active_invalidate_count)
                 kvm->mn_active_invalidate_count = 0;
         else
                 WARN_ON(kvm->mmu_invalidate_in_progress);
 #else
         kvm_flush_shadow_all(kvm);
 #endif
         kvm_arch_destroy_vm(kvm);
         kvm_destroy_devices(kvm);
         for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
                 kvm_free_memslots(kvm, &kvm->__memslots[i][0]);
                 kvm_free_memslots(kvm, &kvm->__memslots[i][1]);
         }
         cleanup_srcu_struct(&kvm->irq_srcu);
         cleanup_srcu_struct(&kvm->srcu);
 #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
         xa_destroy(&kvm->mem_attr_array);
 #endif
         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);
 
 /*
  * Make sure the vm is not during destruction, which is a safe version of
  * kvm_get_kvm().  Return true if kvm referenced successfully, false otherwise.
  */
 bool kvm_get_kvm_safe(struct kvm *kvm)
 {
         return refcount_inc_not_zero(&kvm->users_count);
 }
 EXPORT_SYMBOL_GPL(kvm_get_kvm_safe);
 
 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 = kvm_dirty_bitmap_bytes(memslot);
 
         memslot->dirty_bitmap = __vcalloc(2, dirty_bytes, GFP_KERNEL_ACCOUNT);
         if (!memslot->dirty_bitmap)
                 return -ENOMEM;
 
         return 0;
 }
 
 static struct kvm_memslots *kvm_get_inactive_memslots(struct kvm *kvm, int as_id)
 {
         struct kvm_memslots *active = __kvm_memslots(kvm, as_id);
         int node_idx_inactive = active->node_idx ^ 1;
 
         return &kvm->__memslots[as_id][node_idx_inactive];
 }
 
 /*
  * Helper to get the address space ID when one of memslot pointers may be NULL.
  * This also serves as a sanity that at least one of the pointers is non-NULL,
  * and that their address space IDs don't diverge.
  */
 static int kvm_memslots_get_as_id(struct kvm_memory_slot *a,
                                   struct kvm_memory_slot *b)
 {
         if (WARN_ON_ONCE(!a && !b))
                 return 0;
 
         if (!a)
                 return b->as_id;
         if (!b)
                 return a->as_id;
 
         WARN_ON_ONCE(a->as_id != b->as_id);
         return a->as_id;
 }
 
 static void kvm_insert_gfn_node(struct kvm_memslots *slots,
                                 struct kvm_memory_slot *slot)
 {
         struct rb_root *gfn_tree = &slots->gfn_tree;
         struct rb_node **node, *parent;
         int idx = slots->node_idx;
 
         parent = NULL;
         for (node = &gfn_tree->rb_node; *node; ) {
                 struct kvm_memory_slot *tmp;
 
                 tmp = container_of(*node, struct kvm_memory_slot, gfn_node[idx]);
                 parent = *node;
                 if (slot->base_gfn < tmp->base_gfn)
                         node = &(*node)->rb_left;
                 else if (slot->base_gfn > tmp->base_gfn)
                         node = &(*node)->rb_right;
                 else
                         BUG();
         }
 
         rb_link_node(&slot->gfn_node[idx], parent, node);
         rb_insert_color(&slot->gfn_node[idx], gfn_tree);
 }
 
 static void kvm_erase_gfn_node(struct kvm_memslots *slots,
                                struct kvm_memory_slot *slot)
 {
         rb_erase(&slot->gfn_node[slots->node_idx], &slots->gfn_tree);
 }
 
 static void kvm_replace_gfn_node(struct kvm_memslots *slots,
                                  struct kvm_memory_slot *old,
                                  struct kvm_memory_slot *new)
 {
         int idx = slots->node_idx;
 
         WARN_ON_ONCE(old->base_gfn != new->base_gfn);
 
         rb_replace_node(&old->gfn_node[idx], &new->gfn_node[idx],
                         &slots->gfn_tree);
 }
 
 /*
  * Replace @old with @new in the inactive memslots.
  *
  * With NULL @old this simply adds @new.
  * With NULL @new this simply removes @old.
  *
  * If @new is non-NULL its hva_node[slots_idx] range has to be set
  * appropriately.
  */
 static void kvm_replace_memslot(struct kvm *kvm,
                                 struct kvm_memory_slot *old,
                                 struct kvm_memory_slot *new)
 {
         int as_id = kvm_memslots_get_as_id(old, new);
         struct kvm_memslots *slots = kvm_get_inactive_memslots(kvm, as_id);
         int idx = slots->node_idx;
 
         if (old) {
                 hash_del(&old->id_node[idx]);
                 interval_tree_remove(&old->hva_node[idx], &slots->hva_tree);
 
                 if ((long)old == atomic_long_read(&slots->last_used_slot))
                         atomic_long_set(&slots->last_used_slot, (long)new);
 
                 if (!new) {
                         kvm_erase_gfn_node(slots, old);
                         return;
                 }
         }
 
         /*
          * Initialize @new's hva range.  Do this even when replacing an @old
          * slot, kvm_copy_memslot() deliberately does not touch node data.
          */
         new->hva_node[idx].start = new->userspace_addr;
         new->hva_node[idx].last = new->userspace_addr +
                                   (new->npages << PAGE_SHIFT) - 1;
 
         /*
          * (Re)Add the new memslot.  There is no O(1) interval_tree_replace(),
          * hva_node needs to be swapped with remove+insert even though hva can't
          * change when replacing an existing slot.
          */
         hash_add(slots->id_hash, &new->id_node[idx], new->id);
         interval_tree_insert(&new->hva_node[idx], &slots->hva_tree);
 
         /*
          * If the memslot gfn is unchanged, rb_replace_node() can be used to
          * switch the node in the gfn tree instead of removing the old and
          * inserting the new as two separate operations. Replacement is a
          * single O(1) operation versus two O(log(n)) operations for
          * remove+insert.
          */
         if (old && old->base_gfn == new->base_gfn) {
                 kvm_replace_gfn_node(slots, old, new);
         } else {
                 if (old)
                         kvm_erase_gfn_node(slots, old);
                 kvm_insert_gfn_node(slots, new);
         }
 }
 
 /*
  * Flags that do not access any of the extra space of struct
  * kvm_userspace_memory_region2.  KVM_SET_USER_MEMORY_REGION_V1_FLAGS
  * only allows these.
  */
 #define KVM_SET_USER_MEMORY_REGION_V1_FLAGS \
         (KVM_MEM_LOG_DIRTY_PAGES | KVM_MEM_READONLY)
 
 static int check_memory_region_flags(struct kvm *kvm,
                                      const struct kvm_userspace_memory_region2 *mem)
 {
         u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES;
 
         if (kvm_arch_has_private_mem(kvm))
                 valid_flags |= KVM_MEM_GUEST_MEMFD;
 
         /* Dirty logging private memory is not currently supported. */
         if (mem->flags & KVM_MEM_GUEST_MEMFD)
                 valid_flags &= ~KVM_MEM_LOG_DIRTY_PAGES;
 
 #ifdef CONFIG_HAVE_KVM_READONLY_MEM
         /*
          * GUEST_MEMFD is incompatible with read-only memslots, as writes to
          * read-only memslots have emulated MMIO, not page fault, semantics,
          * and KVM doesn't allow emulated MMIO for private memory.
          */
         if (!(mem->flags & KVM_MEM_GUEST_MEMFD))
                 valid_flags |= KVM_MEM_READONLY;
 #endif
 
         if (mem->flags & ~valid_flags)
                 return -EINVAL;
 
         return 0;
 }
 
 static void kvm_swap_active_memslots(struct kvm *kvm, int as_id)
 {
         struct kvm_memslots *slots = kvm_get_inactive_memslots(kvm, as_id);
 
         /* Grab the generation from the activate memslots. */
         u64 gen = __kvm_memslots(kvm, as_id)->generation;
 
         WARN_ON(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS);
         slots->generation = gen | KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS;
 
         /*
          * Do not store the new memslots while there are invalidations in
          * progress, otherwise the locking in invalidate_range_start and
          * invalidate_range_end will be unbalanced.
          */
         spin_lock(&kvm->mn_invalidate_lock);
         prepare_to_rcuwait(&kvm->mn_memslots_update_rcuwait);
         while (kvm->mn_active_invalidate_count) {
                 set_current_state(TASK_UNINTERRUPTIBLE);
                 spin_unlock(&kvm->mn_invalidate_lock);
                 schedule();
                 spin_lock(&kvm->mn_invalidate_lock);
         }
         finish_rcuwait(&kvm->mn_memslots_update_rcuwait);
         rcu_assign_pointer(kvm->memslots[as_id], slots);
         spin_unlock(&kvm->mn_invalidate_lock);
 
         /*
          * 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_arch_nr_memslot_as_ids(kvm);
 
         kvm_arch_memslots_updated(kvm, gen);
 
         slots->generation = gen;
 }
 
 static int kvm_prepare_memory_region(struct kvm *kvm,
                                      const struct kvm_memory_slot *old,
                                      struct kvm_memory_slot *new,
                                      enum kvm_mr_change change)
 {
         int r;
 
         /*
          * If dirty logging is disabled, nullify the bitmap; the old bitmap
          * will be freed on "commit".  If logging is enabled in both old and
          * new, reuse the existing bitmap.  If logging is enabled only in the
          * new and KVM isn't using a ring buffer, allocate and initialize a
          * new bitmap.
          */
         if (change != KVM_MR_DELETE) {
                 if (!(new->flags & KVM_MEM_LOG_DIRTY_PAGES))
                         new->dirty_bitmap = NULL;
                 else if (old && old->dirty_bitmap)
                         new->dirty_bitmap = old->dirty_bitmap;
                 else if (kvm_use_dirty_bitmap(kvm)) {
                         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_arch_prepare_memory_region(kvm, old, new, change);
 
         /* Free the bitmap on failure if it was allocated above. */
         if (r && new && new->dirty_bitmap && (!old || !old->dirty_bitmap))
                 kvm_destroy_dirty_bitmap(new);
 
         return r;
 }
 
 static void kvm_commit_memory_region(struct kvm *kvm,
                                      struct kvm_memory_slot *old,
                                      const struct kvm_memory_slot *new,
                                      enum kvm_mr_change change)
 {
         int old_flags = old ? old->flags : 0;
         int new_flags = new ? new->flags : 0;
         /*
          * Update the total number of memslot pages before calling the arch
          * hook so that architectures can consume the result directly.
          */
         if (change == KVM_MR_DELETE)
                 kvm->nr_memslot_pages -= old->npages;
         else if (change == KVM_MR_CREATE)
                 kvm->nr_memslot_pages += new->npages;
 
         if ((old_flags ^ new_flags) & KVM_MEM_LOG_DIRTY_PAGES) {
                 int change = (new_flags & KVM_MEM_LOG_DIRTY_PAGES) ? 1 : -1;
                 atomic_set(&kvm->nr_memslots_dirty_logging,
                            atomic_read(&kvm->nr_memslots_dirty_logging) + change);
         }
 
         kvm_arch_commit_memory_region(kvm, old, new, change);
 
         switch (change) {
         case KVM_MR_CREATE:
                 /* Nothing more to do. */
                 break;
         case KVM_MR_DELETE:
                 /* Free the old memslot and all its metadata. */
                 kvm_free_memslot(kvm, old);
                 break;
         case KVM_MR_MOVE:
         case KVM_MR_FLAGS_ONLY:
                 /*
                  * Free the dirty bitmap as needed; the below check encompasses
                  * both the flags and whether a ring buffer is being used)
                  */
                 if (old->dirty_bitmap && !new->dirty_bitmap)
                         kvm_destroy_dirty_bitmap(old);
 
                 /*
                  * The final quirk.  Free the detached, old slot, but only its
                  * memory, not any metadata.  Metadata, including arch specific
                  * data, may be reused by @new.
                  */
                 kfree(old);
                 break;
         default:
                 BUG();
         }
 }
 
 /*
  * Activate @new, which must be installed in the inactive slots by the caller,
  * by swapping the active slots and then propagating @new to @old once @old is
  * unreachable and can be safely modified.
  *
  * With NULL @old this simply adds @new to @active (while swapping the sets).
  * With NULL @new this simply removes @old from @active and frees it
  * (while also swapping the sets).
  */
 static void kvm_activate_memslot(struct kvm *kvm,
                                  struct kvm_memory_slot *old,
                                  struct kvm_memory_slot *new)
 {
         int as_id = kvm_memslots_get_as_id(old, new);
 
         kvm_swap_active_memslots(kvm, as_id);
 
         /* Propagate the new memslot to the now inactive memslots. */
         kvm_replace_memslot(kvm, old, new);
 }
 
 static void kvm_copy_memslot(struct kvm_memory_slot *dest,
                              const struct kvm_memory_slot *src)
 {
         dest->base_gfn = src->base_gfn;
         dest->npages = src->npages;
         dest->dirty_bitmap = src->dirty_bitmap;
         dest->arch = src->arch;
         dest->userspace_addr = src->userspace_addr;
         dest->flags = src->flags;
         dest->id = src->id;
         dest->as_id = src->as_id;
 }
 
 static void kvm_invalidate_memslot(struct kvm *kvm,
                                    struct kvm_memory_slot *old,
                                    struct kvm_memory_slot *invalid_slot)
 {
         /*
          * Mark the current slot INVALID.  As with all memslot modifications,
          * this must be done on an unreachable slot to avoid modifying the
          * current slot in the active tree.
          */
         kvm_copy_memslot(invalid_slot, old);
         invalid_slot->flags |= KVM_MEMSLOT_INVALID;
         kvm_replace_memslot(kvm, old, invalid_slot);
 
         /*
          * Activate the slot that is now marked INVALID, but don't propagate
          * the slot to the now inactive slots. The slot is either going to be
          * deleted or recreated as a new slot.
          */
         kvm_swap_active_memslots(kvm, old->as_id);
 
         /*
          * 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, old);
         kvm_arch_guest_memory_reclaimed(kvm);
 
         /* Was released by kvm_swap_active_memslots(), reacquire. */
         mutex_lock(&kvm->slots_arch_lock);
 
         /*
          * Copy the arch-specific field of the newly-installed slot back to the
          * old slot as the arch data could have changed between releasing
          * slots_arch_lock in kvm_swap_active_memslots() and re-acquiring the lock
          * above.  Writers are required to retrieve memslots *after* acquiring
          * slots_arch_lock, thus the active slot's data is guaranteed to be fresh.
          */
         old->arch = invalid_slot->arch;
 }
 
 static void kvm_create_memslot(struct kvm *kvm,
                                struct kvm_memory_slot *new)
 {
         /* Add the new memslot to the inactive set and activate. */
         kvm_replace_memslot(kvm, NULL, new);
         kvm_activate_memslot(kvm, NULL, new);
 }
 
 static void kvm_delete_memslot(struct kvm *kvm,
                                struct kvm_memory_slot *old,
                                struct kvm_memory_slot *invalid_slot)
 {
         /*
          * Remove the old memslot (in the inactive memslots) by passing NULL as
          * the "new" slot, and for the invalid version in the active slots.
          */
         kvm_replace_memslot(kvm, old, NULL);
         kvm_activate_memslot(kvm, invalid_slot, NULL);
 }
 
 static void kvm_move_memslot(struct kvm *kvm,
                              struct kvm_memory_slot *old,
                              struct kvm_memory_slot *new,
                              struct kvm_memory_slot *invalid_slot)
 {
         /*
          * Replace the old memslot in the inactive slots, and then swap slots
          * and replace the current INVALID with the new as well.
          */
         kvm_replace_memslot(kvm, old, new);
         kvm_activate_memslot(kvm, invalid_slot, new);
 }
 
 static void kvm_update_flags_memslot(struct kvm *kvm,
                                      struct kvm_memory_slot *old,
                                      struct kvm_memory_slot *new)
 {
         /*
          * Similar to the MOVE case, but the slot doesn't need to be zapped as
          * an intermediate step. Instead, the old memslot is simply replaced
          * with a new, updated copy in both memslot sets.
          */
         kvm_replace_memslot(kvm, old, new);
         kvm_activate_memslot(kvm, old, new);
 }
 
 static int kvm_set_memslot(struct kvm *kvm,
                            struct kvm_memory_slot *old,
                            struct kvm_memory_slot *new,
                            enum kvm_mr_change change)
 {
         struct kvm_memory_slot *invalid_slot;
         int r;
 
         /*
          * Released in kvm_swap_active_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 kvm_swap_active_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);
 
         /*
          * Invalidate the old slot if it's being deleted or moved.  This is
          * done prior to actually deleting/moving the memslot to allow vCPUs to
          * continue running by ensuring there are no mappings or shadow pages
          * for the memslot when it is deleted/moved.  Without pre-invalidation
          * (and without a lock), a window would exist between effecting the
          * delete/move and committing the changes in arch code where KVM or a
          * guest could access a non-existent memslot.
          *
          * Modifications are done on a temporary, unreachable slot.  The old
          * slot needs to be preserved in case a later step fails and the
          * invalidation needs to be reverted.
          */
         if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) {
                 invalid_slot = kzalloc(sizeof(*invalid_slot), GFP_KERNEL_ACCOUNT);
                 if (!invalid_slot) {
                         mutex_unlock(&kvm->slots_arch_lock);
                         return -ENOMEM;
                 }
                 kvm_invalidate_memslot(kvm, old, invalid_slot);
         }
 
         r = kvm_prepare_memory_region(kvm, old, new, change);
         if (r) {
                 /*
                  * For DELETE/MOVE, revert the above INVALID change.  No
                  * modifications required since the original slot was preserved
                  * in the inactive slots.  Changing the active memslots also
                  * release slots_arch_lock.
                  */
                 if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) {
                         kvm_activate_memslot(kvm, invalid_slot, old);
                         kfree(invalid_slot);
                 } else {
                         mutex_unlock(&kvm->slots_arch_lock);
                 }
                 return r;
         }
 
         /*
          * For DELETE and MOVE, the working slot is now active as the INVALID
          * version of the old slot.  MOVE is particularly special as it reuses
          * the old slot and returns a copy of the old slot (in working_slot).
          * For CREATE, there is no old slot.  For DELETE and FLAGS_ONLY, the
          * old slot is detached but otherwise preserved.
          */
         if (change == KVM_MR_CREATE)
                 kvm_create_memslot(kvm, new);
         else if (change == KVM_MR_DELETE)
                 kvm_delete_memslot(kvm, old, invalid_slot);
         else if (change == KVM_MR_MOVE)
                 kvm_move_memslot(kvm, old, new, invalid_slot);
         else if (change == KVM_MR_FLAGS_ONLY)
                 kvm_update_flags_memslot(kvm, old, new);
         else
                 BUG();
 
         /* Free the temporary INVALID slot used for DELETE and MOVE. */
         if (change == KVM_MR_DELETE || change == KVM_MR_MOVE)
                 kfree(invalid_slot);
 
         /*
          * No need to refresh new->arch, changes after dropping slots_arch_lock
          * will directly hit the final, active memslot.  Architectures are
          * responsible for knowing that new->arch may be stale.
          */
         kvm_commit_memory_region(kvm, old, new, change);
 
         return 0;
 }
 
 static bool kvm_check_memslot_overlap(struct kvm_memslots *slots, int id,
                                       gfn_t start, gfn_t end)
 {
         struct kvm_memslot_iter iter;
 
         kvm_for_each_memslot_in_gfn_range(&iter, slots, start, end) {
                 if (iter.slot->id != id)
                         return true;
         }
 
         return false;
 }
 
 /*
  * 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_region2 *mem)
 {
         struct kvm_memory_slot *old, *new;
         struct kvm_memslots *slots;
         enum kvm_mr_change change;
         unsigned long npages;
         gfn_t base_gfn;
         int as_id, id;
         int r;
 
         r = check_memory_region_flags(kvm, mem);
         if (r)
                 return r;
 
         as_id = mem->slot >> 16;
         id = (u16)mem->slot;
 
         /* General sanity checks */
         if ((mem->memory_size & (PAGE_SIZE - 1)) ||
             (mem->memory_size != (unsigned long)mem->memory_size))
                 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 (mem->flags & KVM_MEM_GUEST_MEMFD &&
             (mem->guest_memfd_offset & (PAGE_SIZE - 1) ||
              mem->guest_memfd_offset + mem->memory_size < mem->guest_memfd_offset))
                 return -EINVAL;
         if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_MEM_SLOTS_NUM)
                 return -EINVAL;
         if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr)
                 return -EINVAL;
         if ((mem->memory_size >> PAGE_SHIFT) > KVM_MEM_MAX_NR_PAGES)
                 return -EINVAL;
 
         slots = __kvm_memslots(kvm, as_id);
 
         /*
          * Note, the old memslot (and the pointer itself!) may be invalidated
          * and/or destroyed by kvm_set_memslot().
          */
         old = id_to_memslot(slots, id);
 
         if (!mem->memory_size) {
                 if (!old || !old->npages)
                         return -EINVAL;
 
                 if (WARN_ON_ONCE(kvm->nr_memslot_pages < old->npages))
                         return -EIO;
 
                 return kvm_set_memslot(kvm, old, NULL, KVM_MR_DELETE);
         }
 
         base_gfn = (mem->guest_phys_addr >> PAGE_SHIFT);
         npages = (mem->memory_size >> PAGE_SHIFT);
 
         if (!old || !old->npages) {
                 change = KVM_MR_CREATE;
 
                 /*
                  * To simplify KVM internals, the total number of pages across
                  * all memslots must fit in an unsigned long.
                  */
                 if ((kvm->nr_memslot_pages + npages) < kvm->nr_memslot_pages)
                         return -EINVAL;
         } else { /* Modify an existing slot. */
                 /* Private memslots are immutable, they can only be deleted. */
                 if (mem->flags & KVM_MEM_GUEST_MEMFD)
                         return -EINVAL;
                 if ((mem->userspace_addr != old->userspace_addr) ||
                     (npages != old->npages) ||
                     ((mem->flags ^ old->flags) & KVM_MEM_READONLY))
                         return -EINVAL;
 
                 if (base_gfn != old->base_gfn)
                         change = KVM_MR_MOVE;
                 else if (mem->flags != old->flags)
                         change = KVM_MR_FLAGS_ONLY;
                 else /* Nothing to change. */
                         return 0;
         }
 
         if ((change == KVM_MR_CREATE || change == KVM_MR_MOVE) &&
             kvm_check_memslot_overlap(slots, id, base_gfn, base_gfn + npages))
                 return -EEXIST;
 
         /* Allocate a slot that will persist in the memslot. */
         new = kzalloc(sizeof(*new), GFP_KERNEL_ACCOUNT);
         if (!new)
                 return -ENOMEM;
 
         new->as_id = as_id;
         new->id = id;
         new->base_gfn = base_gfn;
         new->npages = npages;
         new->flags = mem->flags;
         new->userspace_addr = mem->userspace_addr;
         if (mem->flags & KVM_MEM_GUEST_MEMFD) {
                 r = kvm_gmem_bind(kvm, new, mem->guest_memfd, mem->guest_memfd_offset);
                 if (r)
                         goto out;
         }
 
         r = kvm_set_memslot(kvm, old, new, change);
         if (r)
                 goto out_unbind;
 
         return 0;
 
 out_unbind:
         if (mem->flags & KVM_MEM_GUEST_MEMFD)
                 kvm_gmem_unbind(new);
 out:
         kfree(new);
         return r;
 }
 EXPORT_SYMBOL_GPL(__kvm_set_memory_region);
 
 int kvm_set_memory_region(struct kvm *kvm,
                           const struct kvm_userspace_memory_region2 *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_region2 *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 may be exclusive to dirty log tracking */
         if (!kvm_use_dirty_bitmap(kvm))
                 return -ENXIO;
 
         *memslot = NULL;
         *is_dirty = 0;
 
         as_id = log->slot >> 16;
         id = (u16)log->slot;
         if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || 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 may be exclusive to dirty log tracking */
         if (!kvm_use_dirty_bitmap(kvm))
                 return -ENXIO;
 
         as_id = log->slot >> 16;
         id = (u16)log->slot;
         if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || 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_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 may be exclusive to dirty log tracking */
         if (!kvm_use_dirty_bitmap(kvm))
                 return -ENXIO;
 
         as_id = log->slot >> 16;
         id = (u16)log->slot;
         if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || 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_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 */
 
 #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
 static u64 kvm_supported_mem_attributes(struct kvm *kvm)
 {
         if (!kvm || kvm_arch_has_private_mem(kvm))
                 return KVM_MEMORY_ATTRIBUTE_PRIVATE;
 
         return 0;
 }
 
 /*
  * Returns true if _all_ gfns in the range [@start, @end) have attributes
  * such that the bits in @mask match @attrs.
  */
 bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
                                      unsigned long mask, unsigned long attrs)
 {
         XA_STATE(xas, &kvm->mem_attr_array, start);
         unsigned long index;
         void *entry;
 
         mask &= kvm_supported_mem_attributes(kvm);
         if (attrs & ~mask)
                 return false;
 
         if (end == start + 1)
                 return (kvm_get_memory_attributes(kvm, start) & mask) == attrs;
 
         guard(rcu)();
         if (!attrs)
                 return !xas_find(&xas, end - 1);
 
         for (index = start; index < end; index++) {
                 do {
                         entry = xas_next(&xas);
                 } while (xas_retry(&xas, entry));
 
                 if (xas.xa_index != index ||
                     (xa_to_value(entry) & mask) != attrs)
                         return false;
         }
 
         return true;
 }
 
 static __always_inline void kvm_handle_gfn_range(struct kvm *kvm,
                                                  struct kvm_mmu_notifier_range *range)
 {
         struct kvm_gfn_range gfn_range;
         struct kvm_memory_slot *slot;
         struct kvm_memslots *slots;
         struct kvm_memslot_iter iter;
         bool found_memslot = false;
         bool ret = false;
         int i;
 
         gfn_range.arg = range->arg;
         gfn_range.may_block = range->may_block;
 
         for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
                 slots = __kvm_memslots(kvm, i);
 
                 kvm_for_each_memslot_in_gfn_range(&iter, slots, range->start, range->end) {
                         slot = iter.slot;
                         gfn_range.slot = slot;
 
                         gfn_range.start = max(range->start, slot->base_gfn);
                         gfn_range.end = min(range->end, slot->base_gfn + slot->npages);
                         if (gfn_range.start >= gfn_range.end)
                                 continue;
 
                         if (!found_memslot) {
                                 found_memslot = true;
                                 KVM_MMU_LOCK(kvm);
                                 if (!IS_KVM_NULL_FN(range->on_lock))
                                         range->on_lock(kvm);
                         }
 
                         ret |= range->handler(kvm, &gfn_range);
                 }
         }
 
         if (range->flush_on_ret && ret)
                 kvm_flush_remote_tlbs(kvm);
 
         if (found_memslot)
                 KVM_MMU_UNLOCK(kvm);
 }
 
 static bool kvm_pre_set_memory_attributes(struct kvm *kvm,
                                           struct kvm_gfn_range *range)
 {
         /*
          * Unconditionally add the range to the invalidation set, regardless of
          * whether or not the arch callback actually needs to zap SPTEs.  E.g.
          * if KVM supports RWX attributes in the future and the attributes are
          * going from R=>RW, zapping isn't strictly necessary.  Unconditionally
          * adding the range allows KVM to require that MMU invalidations add at
          * least one range between begin() and end(), e.g. allows KVM to detect
          * bugs where the add() is missed.  Relaxing the rule *might* be safe,
          * but it's not obvious that allowing new mappings while the attributes
          * are in flux is desirable or worth the complexity.
          */
         kvm_mmu_invalidate_range_add(kvm, range->start, range->end);
 
         return kvm_arch_pre_set_memory_attributes(kvm, range);
 }
 
 /* Set @attributes for the gfn range [@start, @end). */
 static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
                                      unsigned long attributes)
 {
         struct kvm_mmu_notifier_range pre_set_range = {
                 .start = start,
                 .end = end,
                 .handler = kvm_pre_set_memory_attributes,
                 .on_lock = kvm_mmu_invalidate_begin,
                 .flush_on_ret = true,
                 .may_block = true,
         };
         struct kvm_mmu_notifier_range post_set_range = {
                 .start = start,
                 .end = end,
                 .arg.attributes = attributes,
                 .handler = kvm_arch_post_set_memory_attributes,
                 .on_lock = kvm_mmu_invalidate_end,
                 .may_block = true,
         };
         unsigned long i;
         void *entry;
         int r = 0;
 
         entry = attributes ? xa_mk_value(attributes) : NULL;
 
         mutex_lock(&kvm->slots_lock);
 
         /* Nothing to do if the entire range as the desired attributes. */
         if (kvm_range_has_memory_attributes(kvm, start, end, ~0, attributes))
                 goto out_unlock;
 
         /*
          * Reserve memory ahead of time to avoid having to deal with failures
          * partway through setting the new attributes.
          */
         for (i = start; i < end; i++) {
                 r = xa_reserve(&kvm->mem_attr_array, i, GFP_KERNEL_ACCOUNT);
                 if (r)
                         goto out_unlock;
         }
 
         kvm_handle_gfn_range(kvm, &pre_set_range);
 
         for (i = start; i < end; i++) {
                 r = xa_err(xa_store(&kvm->mem_attr_array, i, entry,
                                     GFP_KERNEL_ACCOUNT));
                 KVM_BUG_ON(r, kvm);
         }
 
         kvm_handle_gfn_range(kvm, &post_set_range);
 
 out_unlock:
         mutex_unlock(&kvm->slots_lock);
 
         return r;
 }
 static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
                                            struct kvm_memory_attributes *attrs)
 {
         gfn_t start, end;
 
         /* flags is currently not used. */
         if (attrs->flags)
                 return -EINVAL;
         if (attrs->attributes & ~kvm_supported_mem_attributes(kvm))
                 return -EINVAL;
         if (attrs->size == 0 || attrs->address + attrs->size < attrs->address)
                 return -EINVAL;
         if (!PAGE_ALIGNED(attrs->address) || !PAGE_ALIGNED(attrs->size))
                 return -EINVAL;
 
         start = attrs->address >> PAGE_SHIFT;
         end = (attrs->address + attrs->size) >> PAGE_SHIFT;
 
         /*
          * xarray tracks data using "unsigned long", and as a result so does
          * KVM.  For simplicity, supports generic attributes only on 64-bit
          * architectures.
          */
         BUILD_BUG_ON(sizeof(attrs->attributes) != sizeof(unsigned long));
 
         return kvm_vm_set_mem_attributes(kvm, start, end, attrs->attributes);
 }
 #endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */
 
 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)
 {
         struct kvm_memslots *slots = kvm_vcpu_memslots(vcpu);
         u64 gen = slots->generation;
         struct kvm_memory_slot *slot;
 
         /*
          * This also protects against using a memslot from a different address space,
          * since different address spaces have different generation numbers.
          */
         if (unlikely(gen != vcpu->last_used_slot_gen)) {
                 vcpu->last_used_slot = NULL;
                 vcpu->last_used_slot_gen = gen;
         }
 
         slot = try_get_memslot(vcpu->last_used_slot, gfn);
         if (slot)
                 return slot;
 
         /*
          * Fall back to searching all memslots. We purposely use
          * search_memslots() instead of __gfn_to_memslot() to avoid
          * thrashing the VM-wide last_used_slot in kvm_memslots.
          */
         slot = search_memslots(slots, gfn, false);
         if (slot) {
                 vcpu->last_used_slot = slot;
                 return slot;
         }
 
         return NULL;
 }
 
 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(const struct kvm_memory_slot *slot)
 {
         return slot->flags & KVM_MEM_READONLY;
 }
 
 static unsigned long __gfn_to_hva_many(const 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);
         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 interruptible, bool *writable, kvm_pfn_t *pfn)
 {
         /*
          * When a VCPU accesses a page that is not mapped into the secondary
          * MMU, we lookup the page using GUP to map it, so the guest VCPU can
          * make progress. We always want to honor NUMA hinting faults in that
          * case, because GUP usage corresponds to memory accesses from the VCPU.
          * Otherwise, we'd not trigger NUMA hinting faults once a page is
          * mapped into the secondary MMU and gets accessed by a VCPU.
          *
          * Note that get_user_page_fast_only() and FOLL_WRITE for now
          * implicitly honor NUMA hinting faults and don't need this flag.
          */
         unsigned int flags = FOLL_HWPOISON | FOLL_HONOR_NUMA_FAULT;
         struct page *page;
         int npages;
 
         might_sleep();
 
         if (writable)
                 *writable = write_fault;
 
         if (write_fault)
                 flags |= FOLL_WRITE;
         if (async)
                 flags |= FOLL_NOWAIT;
         if (interruptible)
                 flags |= FOLL_INTERRUPTIBLE;
 
         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)
 {
         struct page *page = kvm_pfn_to_refcounted_page(pfn);
 
         if (!page)
                 return 1;
 
         return get_page_unless_zero(page);
 }
 
 static int hva_to_pfn_remapped(struct vm_area_struct *vma,
                                unsigned long addr, bool write_fault,
                                bool *writable, kvm_pfn_t *p_pfn)
 {
         kvm_pfn_t pfn;
         pte_t *ptep;
         pte_t pte;
         spinlock_t *ptl;
         int r;
 
         r = follow_pte(vma, 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, addr, &ptep, &ptl);
                 if (r)
                         return r;
         }
 
         pte = ptep_get(ptep);
 
         if (write_fault && !pte_write(pte)) {
                 pfn = KVM_PFN_ERR_RO_FAULT;
                 goto out;
         }
 
         if (writable)
                 *writable = pte_write(pte);
         pfn = pte_pfn(pte);
 
         /*
          * 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_try_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 is forbidden from sleeping
  * @interruptible: whether the process can be interrupted by non-fatal signals
  * @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.
  */
 kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool interruptible,
                      bool *async, bool write_fault, bool *writable)
 {
         struct vm_area_struct *vma;
         kvm_pfn_t pfn;
         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, interruptible,
                                  writable, &pfn);
         if (npages == 1)
                 return pfn;
         if (npages == -EINTR)
                 return KVM_PFN_ERR_SIGPENDING;
 
         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, 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(const struct kvm_memory_slot *slot, gfn_t gfn,
                                bool atomic, bool interruptible, 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 (kvm_is_error_hva(addr)) {
                 if (writable)
                         *writable = false;
 
                 return addr == KVM_HVA_ERR_RO_BAD ? KVM_PFN_ERR_RO_FAULT :
                                                     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, interruptible, 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, false,
                                     NULL, write_fault, writable, NULL);
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn_prot);
 
 kvm_pfn_t gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn)
 {
         return __gfn_to_pfn_memslot(slot, gfn, false, false, NULL, true,
                                     NULL, NULL);
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot);
 
 kvm_pfn_t gfn_to_pfn_memslot_atomic(const struct kvm_memory_slot *slot, gfn_t gfn)
 {
         return __gfn_to_pfn_memslot(slot, gfn, true, false, 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);
 
 /*
  * Do not use this helper unless you are absolutely certain the gfn _must_ be
  * backed by 'struct page'.  A valid example is if the backing memslot is
  * controlled by KVM.  Note, if the returned page is valid, it's refcount has
  * been elevated by gfn_to_pfn().
  */
 struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
 {
         struct page *page;
         kvm_pfn_t pfn;
 
         pfn = gfn_to_pfn(kvm, gfn);
 
         if (is_error_noslot_pfn(pfn))
                 return KVM_ERR_PTR_BAD_PAGE;
 
         page = kvm_pfn_to_refcounted_page(pfn);
         if (!page)
                 return KVM_ERR_PTR_BAD_PAGE;
 
         return page;
 }
 EXPORT_SYMBOL_GPL(gfn_to_page);
 
 void kvm_release_pfn(kvm_pfn_t pfn, bool dirty)
 {
         if (dirty)
                 kvm_release_pfn_dirty(pfn);
         else
                 kvm_release_pfn_clean(pfn);
 }
 
 int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map)
 {
         kvm_pfn_t pfn;
         void *hva = NULL;
         struct page *page = KVM_UNMAPPED_PAGE;
 
         if (!map)
                 return -EINVAL;
 
         pfn = gfn_to_pfn(vcpu->kvm, gfn);
         if (is_error_noslot_pfn(pfn))
                 return -EINVAL;
 
         if (pfn_valid(pfn)) {
                 page = pfn_to_page(pfn);
                 hva = kmap(page);
 #ifdef CONFIG_HAS_IOMEM
         } else {
                 hva = memremap(pfn_to_hpa(pfn), PAGE_SIZE, MEMREMAP_WB);
 #endif
         }
 
         if (!hva)
                 return -EFAULT;
 
         map->page = page;
         map->hva = hva;
         map->pfn = pfn;
         map->gfn = gfn;
 
         return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_map);
 
 void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map, bool dirty)
 {
         if (!map)
                 return;
 
         if (!map->hva)
                 return;
 
         if (map->page != KVM_UNMAPPED_PAGE)
                 kunmap(map->page);
 #ifdef CONFIG_HAS_IOMEM
         else
                 memunmap(map->hva);
 #endif
 
         if (dirty)
                 kvm_vcpu_mark_page_dirty(vcpu, map->gfn);
 
         kvm_release_pfn(map->pfn, dirty);
 
         map->hva = NULL;
         map->page = NULL;
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_unmap);
 
 static bool kvm_is_ad_tracked_page(struct page *page)
 {
         /*
          * Per page-flags.h, pages tagged PG_reserved "should in general not be
          * touched (e.g. set dirty) except by its owner".
          */
         return !PageReserved(page);
 }
 
 static void kvm_set_page_dirty(struct page *page)
 {
         if (kvm_is_ad_tracked_page(page))
                 SetPageDirty(page);
 }
 
 static void kvm_set_page_accessed(struct page *page)
 {
         if (kvm_is_ad_tracked_page(page))
                 mark_page_accessed(page);
 }
 
 void kvm_release_page_clean(struct page *page)
 {
         WARN_ON(is_error_page(page));
 
         kvm_set_page_accessed(page);
         put_page(page);
 }
 EXPORT_SYMBOL_GPL(kvm_release_page_clean);
 
 void kvm_release_pfn_clean(kvm_pfn_t pfn)
 {
         struct page *page;
 
         if (is_error_noslot_pfn(pfn))
                 return;
 
         page = kvm_pfn_to_refcounted_page(pfn);
         if (!page)
                 return;
 
         kvm_release_page_clean(page);
 }
 EXPORT_SYMBOL_GPL(kvm_release_pfn_clean);
 
 void kvm_release_page_dirty(struct page *page)
 {
         WARN_ON(is_error_page(page));
 
         kvm_set_page_dirty(page);
         kvm_release_page_clean(page);
 }
 EXPORT_SYMBOL_GPL(kvm_release_page_dirty);
 
 void kvm_release_pfn_dirty(kvm_pfn_t pfn)
 {
         struct page *page;
 
         if (is_error_noslot_pfn(pfn))
                 return;
 
         page = kvm_pfn_to_refcounted_page(pfn);
         if (!page)
                 return;
 
         kvm_release_page_dirty(page);
 }
 EXPORT_SYMBOL_GPL(kvm_release_pfn_dirty);
 
 /*
  * Note, checking for an error/noslot pfn is the caller's responsibility when
  * directly marking a page dirty/accessed.  Unlike the "release" helpers, the
  * "set" helpers are not to be used when the pfn might point at garbage.
  */
 void kvm_set_pfn_dirty(kvm_pfn_t pfn)
 {
         if (WARN_ON(is_error_noslot_pfn(pfn)))
                 return;
 
         if (pfn_valid(pfn))
                 kvm_set_page_dirty(pfn_to_page(pfn));
 }
 EXPORT_SYMBOL_GPL(kvm_set_pfn_dirty);
 
 void kvm_set_pfn_accessed(kvm_pfn_t pfn)
 {
         if (WARN_ON(is_error_noslot_pfn(pfn)))
                 return;
 
         if (pfn_valid(pfn))
                 kvm_set_page_accessed(pfn_to_page(pfn));
 }
 EXPORT_SYMBOL_GPL(kvm_set_pfn_accessed);
 
 static int next_segment(unsigned long len, int offset)
 {
         if (len > PAGE_SIZE - offset)
                 return PAGE_SIZE - offset;
         else
                 return len;
 }
 
 /* Copy @len bytes from guest memory at '(@gfn * PAGE_SIZE) + @offset' to @data */
 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);
 
 /* Copy @len bytes from @data into guest memory at '(@gfn * PAGE_SIZE) + @offset' */
 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;
 
         if (WARN_ON_ONCE(len + offset > ghc->len))
                 return -EINVAL;
 
         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;
 
         if (WARN_ON_ONCE(len + offset > ghc->len))
                 return -EINVAL;
 
         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,
                              const struct kvm_memory_slot *memslot,
                              gfn_t gfn)
 {
         struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
 
 #ifdef CONFIG_HAVE_KVM_DIRTY_RING
         if (WARN_ON_ONCE(vcpu && vcpu->kvm != kvm))
                 return;
 
         WARN_ON_ONCE(!vcpu && !kvm_arch_allow_write_without_running_vcpu(kvm));
 #endif
 
         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 && vcpu)
                         kvm_dirty_ring_push(vcpu, slot, rel_gfn);
                 else if (memslot->dirty_bitmap)
                         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;
 
         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))
                 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;
 }
 
 /*
  * Block the vCPU until the vCPU is runnable, an event arrives, or a signal is
  * pending.  This is mostly used when halting a vCPU, but may also be used
  * directly for other vCPU non-runnable states, e.g. x86's Wait-For-SIPI.
  */
 bool kvm_vcpu_block(struct kvm_vcpu *vcpu)
 {
         struct rcuwait *wait = kvm_arch_vcpu_get_wait(vcpu);
         bool waited = false;
 
         vcpu->stat.generic.blocking = 1;
 
         preempt_disable();
         kvm_arch_vcpu_blocking(vcpu);
         prepare_to_rcuwait(wait);
         preempt_enable();
 
         for (;;) {
                 set_current_state(TASK_INTERRUPTIBLE);
 
                 if (kvm_vcpu_check_block(vcpu) < 0)
                         break;
 
                 waited = true;
                 schedule();
         }
 
         preempt_disable();
         finish_rcuwait(wait);
         kvm_arch_vcpu_unblocking(vcpu);
         preempt_enable();
 
         vcpu->stat.generic.blocking = 0;
 
         return waited;
 }
 
 static inline void update_halt_poll_stats(struct kvm_vcpu *vcpu, ktime_t start,
                                           ktime_t end, bool success)
 {
         struct kvm_vcpu_stat_generic *stats = &vcpu->stat.generic;
         u64 poll_ns = ktime_to_ns(ktime_sub(end, start));
 
         ++vcpu->stat.generic.halt_attempted_poll;
 
         if (success) {
                 ++vcpu->stat.generic.halt_successful_poll;
 
                 if (!vcpu_valid_wakeup(vcpu))
                         ++vcpu->stat.generic.halt_poll_invalid;
 
                 stats->halt_poll_success_ns += poll_ns;
                 KVM_STATS_LOG_HIST_UPDATE(stats->halt_poll_success_hist, poll_ns);
         } else {
                 stats->halt_poll_fail_ns += poll_ns;
                 KVM_STATS_LOG_HIST_UPDATE(stats->halt_poll_fail_hist, poll_ns);
         }
 }
 
 static unsigned int kvm_vcpu_max_halt_poll_ns(struct kvm_vcpu *vcpu)
 {
         struct kvm *kvm = vcpu->kvm;
 
         if (kvm->override_halt_poll_ns) {
                 /*
                  * Ensure kvm->max_halt_poll_ns is not read before
                  * kvm->override_halt_poll_ns.
                  *
                  * Pairs with the smp_wmb() when enabling KVM_CAP_HALT_POLL.
                  */
                 smp_rmb();
                 return READ_ONCE(kvm->max_halt_poll_ns);
         }
 
         return READ_ONCE(halt_poll_ns);
 }
 
 /*
  * Emulate a vCPU halt condition, e.g. HLT on x86, WFI on arm, etc...  If halt
  * polling is enabled, busy wait for a short time before blocking to avoid the
  * expensive block+unblock sequence if a wake event arrives soon after the vCPU
  * is halted.
  */
 void kvm_vcpu_halt(struct kvm_vcpu *vcpu)
 {
         unsigned int max_halt_poll_ns = kvm_vcpu_max_halt_poll_ns(vcpu);
         bool halt_poll_allowed = !kvm_arch_no_poll(vcpu);
         ktime_t start, cur, poll_end;
         bool waited = false;
         bool do_halt_poll;
         u64 halt_ns;
 
         if (vcpu->halt_poll_ns > max_halt_poll_ns)
                 vcpu->halt_poll_ns = max_halt_poll_ns;
 
         do_halt_poll = halt_poll_allowed && vcpu->halt_poll_ns;
 
         start = cur = poll_end = ktime_get();
         if (do_halt_poll) {
                 ktime_t stop = ktime_add_ns(start, vcpu->halt_poll_ns);
 
                 do {
                         if (kvm_vcpu_check_block(vcpu) < 0)
                                 goto out;
                         cpu_relax();
                         poll_end = cur = ktime_get();
                 } while (kvm_vcpu_can_poll(cur, stop));
         }
 
         waited = kvm_vcpu_block(vcpu);
 
         cur = ktime_get();
         if (waited) {
                 vcpu->stat.generic.halt_wait_ns +=
                         ktime_to_ns(cur) - ktime_to_ns(poll_end);
                 KVM_STATS_LOG_HIST_UPDATE(vcpu->stat.generic.halt_wait_hist,
                                 ktime_to_ns(cur) - ktime_to_ns(poll_end));
         }
 out:
         /* The total time the vCPU was "halted", including polling time. */
         halt_ns = ktime_to_ns(cur) - ktime_to_ns(start);
 
         /*
          * Note, halt-polling is considered successful so long as the vCPU was
          * never actually scheduled out, i.e. even if the wake event arrived
          * after of the halt-polling loop itself, but before the full wait.
          */
         if (do_halt_poll)
                 update_halt_poll_stats(vcpu, start, poll_end, !waited);
 
         if (halt_poll_allowed) {
                 /* Recompute the max halt poll time in case it changed. */
                 max_halt_poll_ns = kvm_vcpu_max_halt_poll_ns(vcpu);
 
                 if (!vcpu_valid_wakeup(vcpu)) {
                         shrink_halt_poll_ns(vcpu);
                 } else if (max_halt_poll_ns) {
                         if (halt_ns <= vcpu->halt_poll_ns)
                                 ;
                         /* we had a long block, shrink polling */
                         else if (vcpu->halt_poll_ns &&
                                  halt_ns > 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 < max_halt_poll_ns &&
                                  halt_ns < max_halt_poll_ns)
                                 grow_halt_poll_ns(vcpu);
                 } else {
                         vcpu->halt_poll_ns = 0;
                 }
         }
 
         trace_kvm_vcpu_wakeup(halt_ns, waited, vcpu_valid_wakeup(vcpu));
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_halt);
 
 bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu)
 {
         if (__kvm_vcpu_wake_up(vcpu)) {
                 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, cpu;
 
         if (kvm_vcpu_wake_up(vcpu))
                 return;
 
         me = get_cpu();
         /*
          * The only state change done outside the vcpu mutex is IN_GUEST_MODE
          * to EXITING_GUEST_MODE.  Therefore the moderately expensive "should
          * kick" check does not need atomic operations if kvm_vcpu_kick is used
          * within the vCPU thread itself.
          */
         if (vcpu == __this_cpu_read(kvm_running_vcpu)) {
                 if (vcpu->mode == IN_GUEST_MODE)
                         WRITE_ONCE(vcpu->mode, EXITING_GUEST_MODE);
                 goto out;
         }
 
         /*
          * Note, the vCPU could get migrated to a different pCPU at any point
          * after kvm_arch_vcpu_should_kick(), which could result in sending an
          * IPI to the previous pCPU.  But, that's ok because the purpose of the
          * IPI is to force the vCPU to leave IN_GUEST_MODE, and migrating the
          * vCPU also requires it to leave IN_GUEST_MODE.
          */
         if (kvm_arch_vcpu_should_kick(vcpu)) {
                 cpu = READ_ONCE(vcpu->cpu);
                 if (cpu != me && (unsigned)cpu < nr_cpu_ids && cpu_online(cpu))
                         smp_send_reschedule(cpu);
         }
 out:
         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;
 }
 
 /*
  * By default, simply query the target vCPU's current mode when checking if a
  * vCPU was preempted in kernel mode.  All architectures except x86 (or more
  * specifical, except VMX) allow querying whether or not a vCPU is in kernel
  * mode even if the vCPU is NOT loaded, i.e. using kvm_arch_vcpu_in_kernel()
  * directly for cross-vCPU checks is functionally correct and accurate.
  */
 bool __weak kvm_arch_vcpu_preempted_in_kernel(struct kvm_vcpu *vcpu)
 {
         return kvm_arch_vcpu_in_kernel(vcpu);
 }
 
 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;
         unsigned long i;
         int yielded = 0;
         int try = 3;
         int pass;
 
         last_boosted_vcpu = READ_ONCE(kvm->last_boosted_vcpu);
         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 (kvm_vcpu_is_blocking(vcpu) && !vcpu_dy_runnable(vcpu))
                                 continue;
 
                         /*
                          * Treat the target vCPU as being in-kernel if it has a
                          * pending interrupt, as the vCPU trying to yield may
                          * be spinning waiting on IPI delivery, i.e. the target
                          * vCPU is in-kernel for the purposes of directed yield.
                          */
                         if (READ_ONCE(vcpu->preempted) && yield_to_kernel_mode &&
                             !kvm_arch_dy_has_pending_interrupt(vcpu) &&
                             !kvm_arch_vcpu_preempted_in_kernel(vcpu))
                                 continue;
                         if (!kvm_vcpu_eligible_for_directed_yield(vcpu))
                                 continue;
 
                         yielded = kvm_vcpu_yield_to(vcpu);
                         if (yielded > 0) {
                                 WRITE_ONCE(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)
 {
 #ifdef CONFIG_HAVE_KVM_DIRTY_RING
         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_pages(vma);
 
         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);
 }
 
 #ifdef __KVM_HAVE_ARCH_VCPU_DEBUGFS
 static int vcpu_get_pid(void *data, u64 *val)
 {
         struct kvm_vcpu *vcpu = data;
 
         rcu_read_lock();
         *val = pid_nr(rcu_dereference(vcpu->pid));
         rcu_read_unlock();
         return 0;
 }
 
 DEFINE_SIMPLE_ATTRIBUTE(vcpu_get_pid_fops, vcpu_get_pid, NULL, "%llu\n");
 
 static void kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu)
 {
         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);
         debugfs_create_file("pid", 0444, debugfs_dentry, vcpu,
                             &vcpu_get_pid_fops);
 
         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, unsigned long id)
 {
         int r;
         struct kvm_vcpu *vcpu;
         struct page *page;
 
         /*
          * KVM tracks vCPU IDs as 'int', be kind to userspace and reject
          * too-large values instead of silently truncating.
          *
          * Ensure KVM_MAX_VCPU_IDS isn't pushed above INT_MAX without first
          * changing the storage type (at the very least, IDs should be tracked
          * as unsigned ints).
          */
         BUILD_BUG_ON(KVM_MAX_VCPU_IDS > INT_MAX);
         if (id >= KVM_MAX_VCPU_IDS)
                 return -EINVAL;
 
         mutex_lock(&kvm->lock);
         if (kvm->created_vcpus >= kvm->max_vcpus) {
                 mutex_unlock(&kvm->lock);
                 return -EINVAL;
         }
 
         r = kvm_arch_vcpu_precreate(kvm, id);
         if (r) {
                 mutex_unlock(&kvm->lock);
                 return r;
         }
 
         kvm->created_vcpus++;
         mutex_unlock(&kvm->lock);
 
         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);
 
 #ifdef CONFIG_LOCKDEP
         /* Ensure that lockdep knows vcpu->mutex is taken *inside* kvm->lock */
         mutex_lock(&vcpu->mutex);
         mutex_unlock(&vcpu->mutex);
 #endif
 
         if (kvm_get_vcpu_by_id(kvm, id)) {
                 r = -EEXIST;
                 goto unlock_vcpu_destroy;
         }
 
         vcpu->vcpu_idx = atomic_read(&kvm->online_vcpus);
         r = xa_reserve(&kvm->vcpu_array, vcpu->vcpu_idx, GFP_KERNEL_ACCOUNT);
         if (r)
                 goto unlock_vcpu_destroy;
 
         /* Now it's all set up, let userspace reach it */
         kvm_get_kvm(kvm);
         r = create_vcpu_fd(vcpu);
         if (r < 0)
                 goto kvm_put_xa_release;
 
         if (KVM_BUG_ON(xa_store(&kvm->vcpu_array, vcpu->vcpu_idx, vcpu, 0), kvm)) {
                 r = -EINVAL;
                 goto kvm_put_xa_release;
         }
 
         /*
          * Pairs with smp_rmb() in kvm_get_vcpu.  Store the vcpu
          * pointer 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;
 
 kvm_put_xa_release:
         kvm_put_kvm_no_destroy(kvm);
         xa_release(&kvm->vcpu_array, vcpu->vcpu_idx);
 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 int kvm_vcpu_stats_release(struct inode *inode, struct file *file)
 {
         struct kvm_vcpu *vcpu = file->private_data;
 
         kvm_put_kvm(vcpu->kvm);
         return 0;
 }
 
 static const struct file_operations kvm_vcpu_stats_fops = {
         .owner = THIS_MODULE,
         .read = kvm_vcpu_stats_read,
         .release = kvm_vcpu_stats_release,
         .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);
         }
 
         kvm_get_kvm(vcpu->kvm);
 
         file->f_mode |= FMODE_PREAD;
         fd_install(fd, file);
 
         return fd;
 }
 
 #ifdef CONFIG_KVM_GENERIC_PRE_FAULT_MEMORY
 static int kvm_vcpu_pre_fault_memory(struct kvm_vcpu *vcpu,
                                      struct kvm_pre_fault_memory *range)
 {
         int idx;
         long r;
         u64 full_size;
 
         if (range->flags)
                 return -EINVAL;
 
         if (!PAGE_ALIGNED(range->gpa) ||
             !PAGE_ALIGNED(range->size) ||
             range->gpa + range->size <= range->gpa)
                 return -EINVAL;
 
         vcpu_load(vcpu);
         idx = srcu_read_lock(&vcpu->kvm->srcu);
 
         full_size = range->size;
         do {
                 if (signal_pending(current)) {
                         r = -EINTR;
                         break;
                 }
 
                 r = kvm_arch_vcpu_pre_fault_memory(vcpu, range);
                 if (WARN_ON_ONCE(r == 0 || r == -EIO))
                         break;
 
                 if (r < 0)
                         break;
 
                 range->size -= r;
                 range->gpa += r;
                 cond_resched();
         } while (range->size);
 
         srcu_read_unlock(&vcpu->kvm->srcu, idx);
         vcpu_put(vcpu);
 
         /* Return success if at least one page was mapped successfully.  */
         return full_size == range->size ? r : 0;
 }
 #endif
 
 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 || vcpu->kvm->vm_dead)
                 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);
                 }
                 vcpu->wants_to_run = !READ_ONCE(vcpu->run->immediate_exit__unsafe);
                 r = kvm_arch_vcpu_ioctl_run(vcpu);
                 vcpu->wants_to_run = false;
 
                 trace_kvm_userspace_exit(vcpu->run->exit_reason, r);
                 break;
         }
         case KVM_GET_REGS: {
                 struct kvm_regs *kvm_regs;
 
                 r = -ENOMEM;
                 kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL);
                 if (!kvm_regs)
                         goto out;
                 r = kvm_arch_vcpu_ioctl_get_regs(vcpu, kvm_regs);
                 if (r)
                         goto out_free1;
                 r = -EFAULT;
                 if (copy_to_user(argp, kvm_regs, sizeof(struct kvm_regs)))
                         goto out_free1;
                 r = 0;
 out_free1:
                 kfree(kvm_regs);
                 break;
         }
         case KVM_SET_REGS: {
                 struct kvm_regs *kvm_regs;
 
                 kvm_regs = memdup_user(argp, sizeof(*kvm_regs));
                 if (IS_ERR(kvm_regs)) {
                         r = PTR_ERR(kvm_regs);
                         goto out;
                 }
                 r = kvm_arch_vcpu_ioctl_set_regs(vcpu, kvm_regs);
                 kfree(kvm_regs);
                 break;
         }
         case KVM_GET_SREGS: {
                 kvm_sregs = kzalloc(sizeof(struct kvm_sregs), GFP_KERNEL);
                 r = -ENOMEM;
                 if (!kvm_sregs)
                         goto out;
                 r = kvm_arch_vcpu_ioctl_get_sregs(vcpu, kvm_sregs);
                 if (r)
                         goto out;
                 r = -EFAULT;
                 if (copy_to_user(argp, kvm_sregs, sizeof(struct kvm_sregs)))
                         goto out;
                 r = 0;
                 break;
         }
         case KVM_SET_SREGS: {
                 kvm_sregs = memdup_user(argp, sizeof(*kvm_sregs));
                 if (IS_ERR(kvm_sregs)) {
                         r = PTR_ERR(kvm_sregs);
                         kvm_sregs = NULL;
                         goto out;
                 }
                 r = kvm_arch_vcpu_ioctl_set_sregs(vcpu, kvm_sregs);
                 break;
         }
         case KVM_GET_MP_STATE: {
                 struct kvm_mp_state mp_state;
 
                 r = kvm_arch_vcpu_ioctl_get_mpstate(vcpu, &mp_state);
                 if (r)
                         goto out;
                 r = -EFAULT;
                 if (copy_to_user(argp, &mp_state, sizeof(mp_state)))
                         goto out;
                 r = 0;
                 break;
         }
         case KVM_SET_MP_STATE: {
                 struct kvm_mp_state mp_state;
 
                 r = -EFAULT;
                 if (copy_from_user(&mp_state, argp, sizeof(mp_state)))
                         goto out;
                 r = kvm_arch_vcpu_ioctl_set_mpstate(vcpu, &mp_state);
                 break;
         }
         case KVM_TRANSLATE: {
                 struct kvm_translation tr;
 
                 r = -EFAULT;
                 if (copy_from_user(&tr, argp, sizeof(tr)))
                         goto out;
                 r = kvm_arch_vcpu_ioctl_translate(vcpu, &tr);
                 if (r)
                         goto out;
                 r = -EFAULT;
                 if (copy_to_user(argp, &tr, sizeof(tr)))
                         goto out;
                 r = 0;
                 break;
         }
         case KVM_SET_GUEST_DEBUG: {
                 struct kvm_guest_debug dbg;
 
                 r = -EFAULT;
                 if (copy_from_user(&dbg, argp, sizeof(dbg)))
                         goto out;
                 r = kvm_arch_vcpu_ioctl_set_guest_debug(vcpu, &dbg);
                 break;
         }
         case KVM_SET_SIGNAL_MASK: {
                 struct kvm_signal_mask __user *sigmask_arg = argp;
                 struct kvm_signal_mask kvm_sigmask;
                 sigset_t sigset, *p;
 
                 p = NULL;
                 if (argp) {
                         r = -EFAULT;
                         if (copy_from_user(&kvm_sigmask, argp,
                                            sizeof(kvm_sigmask)))
                                 goto out;
                         r = -EINVAL;
                         if (kvm_sigmask.len != sizeof(sigset))
                                 goto out;
                         r = -EFAULT;
                         if (copy_from_user(&sigset, sigmask_arg->sigset,
                                            sizeof(sigset)))
                                 goto out;
                         p = &sigset;
                 }
                 r = kvm_vcpu_ioctl_set_sigmask(vcpu, p);
                 break;
         }
         case KVM_GET_FPU: {
                 fpu = kzalloc(sizeof(struct kvm_fpu), GFP_KERNEL);
                 r = -ENOMEM;
                 if (!fpu)
                         goto out;
                 r = kvm_arch_vcpu_ioctl_get_fpu(vcpu, fpu);
                 if (r)
                         goto out;
                 r = -EFAULT;
                 if (copy_to_user(argp, fpu, sizeof(struct kvm_fpu)))
                         goto out;
                 r = 0;
                 break;
         }
         case KVM_SET_FPU: {
                 fpu = memdup_user(argp, sizeof(*fpu));
                 if (IS_ERR(fpu)) {
                         r = PTR_ERR(fpu);
                         fpu = NULL;
                         goto out;
                 }
                 r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, fpu);
                 break;
         }
         case KVM_GET_STATS_FD: {
                 r = kvm_vcpu_ioctl_get_stats_fd(vcpu);
                 break;
         }
 #ifdef CONFIG_KVM_GENERIC_PRE_FAULT_MEMORY
         case KVM_PRE_FAULT_MEMORY: {
                 struct kvm_pre_fault_memory range;
 
                 r = -EFAULT;
                 if (copy_from_user(&range, argp, sizeof(range)))
                         break;
                 r = kvm_vcpu_pre_fault_memory(vcpu, &range);
                 /* Pass back leftover range. */
                 if (copy_to_user(argp, &range, sizeof(range)))
                         r = -EFAULT;
                 break;
         }
 #endif
         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 || vcpu->kvm->vm_dead)
                 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 || dev->kvm->vm_dead)
                 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_rcu(&dev->vm_node);
                 synchronize_rcu();
                 dev->ops->release(dev);
                 mutex_unlock(&kvm->lock);
         }
 
         kvm_put_kvm(kvm);
         return 0;
 }
 
 static 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;
         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_rcu(&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_rcu(&dev->vm_node);
                 synchronize_rcu();
                 if (ops->release)
                         ops->release(dev);
                 mutex_unlock(&kvm->lock);
                 if (ops->destroy)
                         ops->destroy(dev);
                 return ret;
         }
 
         cd->fd = ret;
         return 0;
 }
 
 static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
 {
         switch (arg) {
         case KVM_CAP_USER_MEMORY:
         case KVM_CAP_USER_MEMORY2:
         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_IRQCHIP
         case KVM_CAP_IRQFD:
 #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_MAX_NR_ADDRESS_SPACES > 1
         case KVM_CAP_MULTI_ADDRESS_SPACE:
                 if (kvm)
                         return kvm_arch_nr_memslot_as_ids(kvm);
                 return KVM_MAX_NR_ADDRESS_SPACES;
 #endif
         case KVM_CAP_NR_MEMSLOTS:
                 return KVM_USER_MEM_SLOTS;
         case KVM_CAP_DIRTY_LOG_RING:
 #ifdef CONFIG_HAVE_KVM_DIRTY_RING_TSO
                 return KVM_DIRTY_RING_MAX_ENTRIES * sizeof(struct kvm_dirty_gfn);
 #else
                 return 0;
 #endif
         case KVM_CAP_DIRTY_LOG_RING_ACQ_REL:
 #ifdef CONFIG_HAVE_KVM_DIRTY_RING_ACQ_REL
                 return KVM_DIRTY_RING_MAX_ENTRIES * sizeof(struct kvm_dirty_gfn);
 #else
                 return 0;
 #endif
 #ifdef CONFIG_NEED_KVM_DIRTY_RING_WITH_BITMAP
         case KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP:
 #endif
         case KVM_CAP_BINARY_STATS_FD:
         case KVM_CAP_SYSTEM_EVENT_DATA:
         case KVM_CAP_DEVICE_CTRL:
                 return 1;
 #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
         case KVM_CAP_MEMORY_ATTRIBUTES:
                 return kvm_supported_mem_attributes(kvm);
 #endif
 #ifdef CONFIG_KVM_PRIVATE_MEM
         case KVM_CAP_GUEST_MEMFD:
                 return !kvm || kvm_arch_has_private_mem(kvm);
 #endif
         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)
 {
         unsigned long 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;
 }
 
 bool kvm_are_all_memslots_empty(struct kvm *kvm)
 {
         int i;
 
         lockdep_assert_held(&kvm->slots_lock);
 
         for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
                 if (!kvm_memslots_empty(__kvm_memslots(kvm, i)))
                         return false;
         }
 
         return true;
 }
 EXPORT_SYMBOL_GPL(kvm_are_all_memslots_empty);
 
 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];
 
                 /*
                  * Ensure kvm->override_halt_poll_ns does not become visible
                  * before kvm->max_halt_poll_ns.
                  *
                  * Pairs with the smp_rmb() in kvm_vcpu_max_halt_poll_ns().
                  */
                 smp_wmb();
                 kvm->override_halt_poll_ns = true;
 
                 return 0;
         }
         case KVM_CAP_DIRTY_LOG_RING:
         case KVM_CAP_DIRTY_LOG_RING_ACQ_REL:
                 if (!kvm_vm_ioctl_check_extension_generic(kvm, cap->cap))
                         return -EINVAL;
 
                 return kvm_vm_ioctl_enable_dirty_log_ring(kvm, cap->args[0]);
         case KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP: {
                 int r = -EINVAL;
 
                 if (!IS_ENABLED(CONFIG_NEED_KVM_DIRTY_RING_WITH_BITMAP) ||
                     !kvm->dirty_ring_size || cap->flags)
                         return r;
 
                 mutex_lock(&kvm->slots_lock);
 
                 /*
                  * For simplicity, allow enabling ring+bitmap if and only if
                  * there are no memslots, e.g. to ensure all memslots allocate
                  * a bitmap after the capability is enabled.
                  */
                 if (kvm_are_all_memslots_empty(kvm)) {
                         kvm->dirty_ring_with_bitmap = true;
                         r = 0;
                 }
 
                 mutex_unlock(&kvm->slots_lock);
 
                 return r;
         }
         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 int kvm_vm_stats_release(struct inode *inode, struct file *file)
 {
         struct kvm *kvm = file->private_data;
 
         kvm_put_kvm(kvm);
         return 0;
 }
 
 static const struct file_operations kvm_vm_stats_fops = {
         .owner = THIS_MODULE,
         .read = kvm_vm_stats_read,
         .release = kvm_vm_stats_release,
         .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);
         }
 
         kvm_get_kvm(kvm);
 
         file->f_mode |= FMODE_PREAD;
         fd_install(fd, file);
 
         return fd;
 }
 
 #define SANITY_CHECK_MEM_REGION_FIELD(field)                                    \
 do {                                                                            \
         BUILD_BUG_ON(offsetof(struct kvm_userspace_memory_region, field) !=             \
                      offsetof(struct kvm_userspace_memory_region2, field));     \
         BUILD_BUG_ON(sizeof_field(struct kvm_userspace_memory_region, field) !=         \
                      sizeof_field(struct kvm_userspace_memory_region2, field)); \
 } while (0)
 
 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 || kvm->vm_dead)
                 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_REGION2:
         case KVM_SET_USER_MEMORY_REGION: {
                 struct kvm_userspace_memory_region2 mem;
                 unsigned long size;
 
                 if (ioctl == KVM_SET_USER_MEMORY_REGION) {
                         /*
                          * Fields beyond struct kvm_userspace_memory_region shouldn't be
                          * accessed, but avoid leaking kernel memory in case of a bug.
                          */
                         memset(&mem, 0, sizeof(mem));
                         size = sizeof(struct kvm_userspace_memory_region);
                 } else {
                         size = sizeof(struct kvm_userspace_memory_region2);
                 }
 
                 /* Ensure the common parts of the two structs are identical. */
                 SANITY_CHECK_MEM_REGION_FIELD(slot);
                 SANITY_CHECK_MEM_REGION_FIELD(flags);
                 SANITY_CHECK_MEM_REGION_FIELD(guest_phys_addr);
                 SANITY_CHECK_MEM_REGION_FIELD(memory_size);
                 SANITY_CHECK_MEM_REGION_FIELD(userspace_addr);
 
                 r = -EFAULT;
                 if (copy_from_user(&mem, argp, size))
                         goto out;
 
                 r = -EINVAL;
                 if (ioctl == KVM_SET_USER_MEMORY_REGION &&
                     (mem.flags & ~KVM_SET_USER_MEMORY_REGION_V1_FLAGS))
                         goto out;
 
                 r = kvm_vm_ioctl_set_memory_region(kvm, &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_array_user(urouting->entries,
                                                      routing.nr, sizeof(*entries));
                         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 */
 #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
         case KVM_SET_MEMORY_ATTRIBUTES: {
                 struct kvm_memory_attributes attrs;
 
                 r = -EFAULT;
                 if (copy_from_user(&attrs, argp, sizeof(attrs)))
                         goto out;
 
                 r = kvm_vm_ioctl_set_mem_attributes(kvm, &attrs);
                 break;
         }
 #endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */
         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;
 #ifdef CONFIG_KVM_PRIVATE_MEM
         case KVM_CREATE_GUEST_MEMFD: {
                 struct kvm_create_guest_memfd guest_memfd;
 
                 r = -EFAULT;
                 if (copy_from_user(&guest_memfd, argp, sizeof(guest_memfd)))
                         goto out;
 
                 r = kvm_gmem_create(kvm, &guest_memfd);
                 break;
         }
 #endif
         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;
         };
 };
 
 long __weak kvm_arch_vm_compat_ioctl(struct file *filp, unsigned int ioctl,
                                      unsigned long arg)
 {
         return -ENOTTY;
 }
 
 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 || kvm->vm_dead)
                 return -EIO;
 
         r = kvm_arch_vm_compat_ioctl(filp, ioctl, arg);
         if (r != -ENOTTY)
                 return r;
 
         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)
 {
         char fdname[ITOA_MAX_LEN + 1];
         int r, fd;
         struct kvm *kvm;
         struct file *file;
 
         fd = get_unused_fd_flags(O_CLOEXEC);
         if (fd < 0)
                 return fd;
 
         snprintf(fdname, sizeof(fdname), "%d", fd);
 
         kvm = kvm_create_vm(type, fdname);
         if (IS_ERR(kvm)) {
                 r = PTR_ERR(kvm);
                 goto put_fd;
         }
 
         file = anon_inode_getfile("kvm-vm", &kvm_vm_fops, kvm, O_RDWR);
         if (IS_ERR(file)) {
                 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).
          */
         kvm_uevent_notify_change(KVM_EVENT_CREATE_VM, kvm);
 
         fd_install(fd, file);
         return fd;
 
 put_kvm:
         kvm_put_kvm(kvm);
 put_fd:
         put_unused_fd(fd);
         return r;
 }
 
 static long kvm_dev_ioctl(struct file *filp,
                           unsigned int ioctl, unsigned long arg)
 {
         int 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;
         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,
 };
 
 #ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING
 __visible bool kvm_rebooting;
 EXPORT_SYMBOL_GPL(kvm_rebooting);
 
 static DEFINE_PER_CPU(bool, hardware_enabled);
 static int kvm_usage_count;
 
 static int __hardware_enable_nolock(void)
 {
         if (__this_cpu_read(hardware_enabled))
                 return 0;
 
         if (kvm_arch_hardware_enable()) {
                 pr_info("kvm: enabling virtualization on CPU%d failed\n",
                         raw_smp_processor_id());
                 return -EIO;
         }
 
         __this_cpu_write(hardware_enabled, true);
         return 0;
 }
 
 static void hardware_enable_nolock(void *failed)
 {
         if (__hardware_enable_nolock())
                 atomic_inc(failed);
 }
 
 static int kvm_online_cpu(unsigned int cpu)
 {
         int ret = 0;
 
         /*
          * Abort the CPU online process if hardware virtualization cannot
          * be enabled. Otherwise running VMs would encounter unrecoverable
          * errors when scheduled to this CPU.
          */
         mutex_lock(&kvm_lock);
         if (kvm_usage_count)
                 ret = __hardware_enable_nolock();
         mutex_unlock(&kvm_lock);
         return ret;
 }
 
 static void hardware_disable_nolock(void *junk)
 {
         /*
          * Note, hardware_disable_all_nolock() tells all online CPUs to disable
          * hardware, not just CPUs that successfully enabled hardware!
          */
         if (!__this_cpu_read(hardware_enabled))
                 return;
 
         kvm_arch_hardware_disable();
 
         __this_cpu_write(hardware_enabled, false);
 }
 
 static int kvm_offline_cpu(unsigned int cpu)
 {
         mutex_lock(&kvm_lock);
         if (kvm_usage_count)
                 hardware_disable_nolock(NULL);
         mutex_unlock(&kvm_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)
 {
         cpus_read_lock();
         mutex_lock(&kvm_lock);
         hardware_disable_all_nolock();
         mutex_unlock(&kvm_lock);
         cpus_read_unlock();
 }
 
 static int hardware_enable_all(void)
 {
         atomic_t failed = ATOMIC_INIT(0);
         int r;
 
         /*
          * Do not enable hardware virtualization if the system is going down.
          * If userspace initiated a forced reboot, e.g. reboot -f, then it's
          * possible for an in-flight KVM_CREATE_VM to trigger hardware enabling
          * after kvm_reboot() is called.  Note, this relies on system_state
          * being set _before_ kvm_reboot(), which is why KVM uses a syscore ops
          * hook instead of registering a dedicated reboot notifier (the latter
          * runs before system_state is updated).
          */
         if (system_state == SYSTEM_HALT || system_state == SYSTEM_POWER_OFF ||
             system_state == SYSTEM_RESTART)
                 return -EBUSY;
 
         /*
          * When onlining a CPU, cpu_online_mask is set before kvm_online_cpu()
          * is called, and so on_each_cpu() between them includes the CPU that
          * is being onlined.  As a result, hardware_enable_nolock() may get
          * invoked before kvm_online_cpu(), which also enables hardware if the
          * usage count is non-zero.  Disable CPU hotplug to avoid attempting to
          * enable hardware multiple times.
          */
         cpus_read_lock();
         mutex_lock(&kvm_lock);
 
         r = 0;
 
         kvm_usage_count++;
         if (kvm_usage_count == 1) {
                 on_each_cpu(hardware_enable_nolock, &failed, 1);
 
                 if (atomic_read(&failed)) {
                         hardware_disable_all_nolock();
                         r = -EBUSY;
                 }
         }
 
         mutex_unlock(&kvm_lock);
         cpus_read_unlock();
 
         return r;
 }
 
 static void kvm_shutdown(void)
 {
         /*
          * Disable hardware virtualization and set kvm_rebooting to indicate
          * that KVM has asynchronously disabled hardware virtualization, i.e.
          * that relevant errors and exceptions aren't entirely unexpected.
          * Some flavors of hardware virtualization need to be disabled before
          * transferring control to firmware (to perform shutdown/reboot), e.g.
          * on x86, virtualization can block INIT interrupts, which are used by
          * firmware to pull APs back under firmware control.  Note, this path
          * is used for both shutdown and reboot scenarios, i.e. neither name is
          * 100% comprehensive.
          */
         pr_info("kvm: exiting hardware virtualization\n");
         kvm_rebooting = true;
         on_each_cpu(hardware_disable_nolock, NULL, 1);
 }
 
 static int kvm_suspend(void)
 {
         /*
          * Secondary CPUs and CPU hotplug are disabled across the suspend/resume
          * callbacks, i.e. no need to acquire kvm_lock to ensure the usage count
          * is stable.  Assert that kvm_lock is not held to ensure the system
          * isn't suspended while KVM is enabling hardware.  Hardware enabling
          * can be preempted, but the task cannot be frozen until it has dropped
          * all locks (userspace tasks are frozen via a fake signal).
          */
         lockdep_assert_not_held(&kvm_lock);
         lockdep_assert_irqs_disabled();
 
         if (kvm_usage_count)
                 hardware_disable_nolock(NULL);
         return 0;
 }
 
 static void kvm_resume(void)
 {
         lockdep_assert_not_held(&kvm_lock);
         lockdep_assert_irqs_disabled();
 
         if (kvm_usage_count)
                 WARN_ON_ONCE(__hardware_enable_nolock());
 }
 
 static struct syscore_ops kvm_syscore_ops = {
         .suspend = kvm_suspend,
         .resume = kvm_resume,
         .shutdown = kvm_shutdown,
 };
 #else /* CONFIG_KVM_GENERIC_HARDWARE_ENABLING */
 static int hardware_enable_all(void)
 {
         return 0;
 }
 
 static void hardware_disable_all(void)
 {
 
 }
 #endif /* CONFIG_KVM_GENERIC_HARDWARE_ENABLING */
 
 static void kvm_iodevice_destructor(struct kvm_io_device *dev)
 {
         if (dev->ops->destructor)
                 dev->ops->destructor(dev);
 }
 
 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;
 }
 
 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;
 
         lockdep_assert_held(&kvm->slots_lock);
 
         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;
         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);
 
         /*
          * If NULL bus is installed, destroy the old bus, including all the
          * attached devices. Otherwise, destroy the caller's device only.
          */
         if (!new_bus) {
                 pr_err("kvm: failed to shrink bus, removing it completely\n");
                 kvm_io_bus_destroy(bus);
                 return -ENOMEM;
         }
 
         kvm_iodevice_destructor(dev);
         kfree(bus);
         return 0;
 }
 
 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)
 {
         int ret;
         struct kvm_stat_data *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.  kvm_get_kvm_safe
         * avoids the race between open and the removal of the debugfs directory.
          */
         if (!kvm_get_kvm_safe(stat_data->kvm))
                 return -ENOENT;
 
         ret = simple_attr_open(inode, file, get,
                                kvm_stats_debugfs_mode(stat_data->desc) & 0222
                                ? set : NULL, fmt);
         if (ret)
                 kvm_put_kvm(stat_data->kvm);
 
         return ret;
 }
 
 static int kvm_debugfs_release(struct inode *inode, struct file *file)
 {
         struct kvm_stat_data *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)
 {
         unsigned long 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)
 {
         unsigned long 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 = 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 = 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);
         if (!env)
                 return;
 
         add_uevent_var(env, "CREATED=%llu", created);
         add_uevent_var(env, "COUNT=%llu", active);
 
         if (type == KVM_EVENT_CREATE_VM) {
                 add_uevent_var(env, "EVENT=create");
                 kvm->userspace_pid = task_pid_nr(current);
         } else if (type == KVM_EVENT_DESTROY_VM) {
                 add_uevent_var(env, "EVENT=destroy");
         }
         add_uevent_var(env, "PID=%d", kvm->userspace_pid);
 
         if (!IS_ERR(kvm->debugfs_dentry)) {
                 char *tmp, *p = kmalloc(PATH_MAX, GFP_KERNEL);
 
                 if (p) {
                         tmp = dentry_path_raw(kvm->debugfs_dentry, p, PATH_MAX);
                         if (!IS_ERR(tmp))
                                 add_uevent_var(env, "STATS_PATH=%s", tmp);
                         kfree(p);
                 }
         }
         /* no need for checks, since we are adding at most only 5 keys */
         env->envp[env->envp_idx++] = NULL;
         kobject_uevent_env(&kvm_dev.this_device->kobj, KOBJ_CHANGE, env->envp);
         kfree(env);
 }
 
 static void kvm_init_debug(void)
 {
         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 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_vcpu_load(vcpu, cpu);
 
         WRITE_ONCE(vcpu->scheduled_out, false);
 }
 
 static void kvm_sched_out(struct preempt_notifier *pn,
                           struct task_struct *next)
 {
         struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);
 
         WRITE_ONCE(vcpu->scheduled_out, true);
 
         if (current->on_rq && vcpu->wants_to_run) {
                 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;
 }
 
 #ifdef CONFIG_GUEST_PERF_EVENTS
 static unsigned int kvm_guest_state(void)
 {
         struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
         unsigned int state;
 
         if (!kvm_arch_pmi_in_guest(vcpu))
                 return 0;
 
         state = PERF_GUEST_ACTIVE;
         if (!kvm_arch_vcpu_in_kernel(vcpu))
                 state |= PERF_GUEST_USER;
 
         return state;
 }
 
 static unsigned long kvm_guest_get_ip(void)
 {
         struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
 
         /* Retrieving the IP must be guarded by a call to kvm_guest_state(). */
         if (WARN_ON_ONCE(!kvm_arch_pmi_in_guest(vcpu)))
                 return 0;
 
         return kvm_arch_vcpu_get_ip(vcpu);
 }
 
 static struct perf_guest_info_callbacks kvm_guest_cbs = {
         .state                  = kvm_guest_state,
         .get_ip                 = kvm_guest_get_ip,
         .handle_intel_pt_intr   = NULL,
 };
 
 void kvm_register_perf_callbacks(unsigned int (*pt_intr_handler)(void))
 {
         kvm_guest_cbs.handle_intel_pt_intr = pt_intr_handler;
         perf_register_guest_info_callbacks(&kvm_guest_cbs);
 }
 void kvm_unregister_perf_callbacks(void)
 {
         perf_unregister_guest_info_callbacks(&kvm_guest_cbs);
 }
 #endif
 
 int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module)
 {
         int r;
         int cpu;
 
 #ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING
         r = cpuhp_setup_state_nocalls(CPUHP_AP_KVM_ONLINE, "kvm/cpu:online",
                                       kvm_online_cpu, kvm_offline_cpu);
         if (r)
                 return r;
 
         register_syscore_ops(&kvm_syscore_ops);
 #endif
 
         /* 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 err_vcpu_cache;
         }
 
         for_each_possible_cpu(cpu) {
                 if (!alloc_cpumask_var_node(&per_cpu(cpu_kick_mask, cpu),
                                             GFP_KERNEL, cpu_to_node(cpu))) {
                         r = -ENOMEM;
                         goto err_cpu_kick_mask;
                 }
         }
 
         r = kvm_irqfd_init();
         if (r)
                 goto err_irqfd;
 
         r = kvm_async_pf_init();
         if (r)
                 goto err_async_pf;
 
         kvm_chardev_ops.owner = module;
         kvm_vm_fops.owner = module;
         kvm_vcpu_fops.owner = module;
         kvm_device_fops.owner = module;
 
         kvm_preempt_ops.sched_in = kvm_sched_in;
         kvm_preempt_ops.sched_out = kvm_sched_out;
 
         kvm_init_debug();
 
         r = kvm_vfio_ops_init();
         if (WARN_ON_ONCE(r))
                 goto err_vfio;
 
         kvm_gmem_init(module);
 
         /*
          * Registration _must_ be the very last thing done, as this exposes
          * /dev/kvm to userspace, i.e. all infrastructure must be setup!
          */
         r = misc_register(&kvm_dev);
         if (r) {
                 pr_err("kvm: misc device register failed\n");
                 goto err_register;
         }
 
         return 0;
 
 err_register:
         kvm_vfio_ops_exit();
 err_vfio:
         kvm_async_pf_deinit();
 err_async_pf:
         kvm_irqfd_exit();
 err_irqfd:
 err_cpu_kick_mask:
         for_each_possible_cpu(cpu)
                 free_cpumask_var(per_cpu(cpu_kick_mask, cpu));
         kmem_cache_destroy(kvm_vcpu_cache);
 err_vcpu_cache:
 #ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING
         unregister_syscore_ops(&kvm_syscore_ops);
         cpuhp_remove_state_nocalls(CPUHP_AP_KVM_ONLINE);
 #endif
         return r;
 }
 EXPORT_SYMBOL_GPL(kvm_init);
 
 void kvm_exit(void)
 {
         int cpu;
 
         /*
          * Note, unregistering /dev/kvm doesn't strictly need to come first,
          * fops_get(), a.k.a. try_module_get(), prevents acquiring references
          * to KVM while the module is being stopped.
          */
         misc_deregister(&kvm_dev);
 
         debugfs_remove_recursive(kvm_debugfs_dir);
         for_each_possible_cpu(cpu)
                 free_cpumask_var(per_cpu(cpu_kick_mask, cpu));
         kmem_cache_destroy(kvm_vcpu_cache);
         kvm_vfio_ops_exit();
         kvm_async_pf_deinit();
 #ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING
         unregister_syscore_ops(&kvm_syscore_ops);
         cpuhp_remove_state_nocalls(CPUHP_AP_KVM_ONLINE);
 #endif
         kvm_irqfd_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 task_struct *parent;
         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)
                 goto out;
 
         /* Wait to be woken up by the spawner before proceeding. */
         kthread_parkme();
 
         if (!kthread_should_stop())
                 err = thread_fn(kvm, data);
 
 out:
         /*
          * Move kthread back to its original cgroup to prevent it lingering in
          * the cgroup of the VM process, after the latter finishes its
          * execution.
          *
          * kthread_stop() waits on the 'exited' completion condition which is
          * set in exit_mm(), via mm_release(), in do_exit(). However, the
          * kthread is removed from the cgroup in the cgroup_exit() which is
          * called after the exit_mm(). This causes the kthread_stop() to return
          * before the kthread actually quits the cgroup.
          */
         rcu_read_lock();
         parent = rcu_dereference(current->real_parent);
         get_task_struct(parent);
         rcu_read_unlock();
         cgroup_attach_task_all(parent, current);
         put_task_struct(parent);
 
         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;
 }