kvm_main.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
 * Kernel-based Virtual Machine driver for Linux
 *
 * This module enables machines with Intel VT-x extensions to run virtual
 * machines without emulation or binary translation.
 *
 * Copyright (C) 2006 Qumranet, Inc.
 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
 *
 * Authors:
 *   Avi Kivity   <avi@qumranet.com>
 *   Yaniv Kamay  <yaniv@qumranet.com>
 */
 
#include <kvm/iodev.h>
 
#include <linux/kvm_host.h>
#include <linux/kvm.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/percpu.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/vmalloc.h>
#include <linux/reboot.h>
#include <linux/debugfs.h>
#include <linux/highmem.h>
#include <linux/file.h>
#include <linux/syscore_ops.h>
#include <linux/cpu.h>
#include <linux/sched/signal.h>
#include <linux/sched/mm.h>
#include <linux/sched/stat.h>
#include <linux/cpumask.h>
#include <linux/smp.h>
#include <linux/anon_inodes.h>
#include <linux/profile.h>
#include <linux/kvm_para.h>
#include <linux/pagemap.h>
#include <linux/mman.h>
#include <linux/swap.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/compat.h>
#include <linux/srcu.h>
#include <linux/hugetlb.h>
#include <linux/slab.h>
#include <linux/sort.h>
#include <linux/bsearch.h>
#include <linux/io.h>
#include <linux/lockdep.h>
#include <linux/kthread.h>
#include <linux/suspend.h>
 
#include <asm/processor.h>
#include <asm/ioctl.h>
#include <linux/uaccess.h>
 
#include "coalesced_mmio.h"
#include "async_pf.h"
#include "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_LICENSE("GPL");
 
/* Architectures should define their poll value according to the halt latency */
unsigned int halt_poll_ns = KVM_HALT_POLL_NS_DEFAULT;
module_param(halt_poll_ns, uint, 0644);
EXPORT_SYMBOL_GPL(halt_poll_ns);
 
/* Default doubles per-vcpu halt_poll_ns. */
unsigned int halt_poll_ns_grow = 2;
module_param(halt_poll_ns_grow, uint, 0644);
EXPORT_SYMBOL_GPL(halt_poll_ns_grow);
 
/* The start value to grow halt_poll_ns from */
unsigned int halt_poll_ns_grow_start = 10000; /* 10us */
module_param(halt_poll_ns_grow_start, uint, 0644);
EXPORT_SYMBOL_GPL(halt_poll_ns_grow_start);
 
/* Default resets per-vcpu halt_poll_ns . */
unsigned int halt_poll_ns_shrink;
module_param(halt_poll_ns_shrink, uint, 0644);
EXPORT_SYMBOL_GPL(halt_poll_ns_shrink);
 
/*
 * Ordering of locks:
 *
 *  kvm->lock --> kvm->slots_lock --> kvm->irq_lock
 */
 
DEFINE_MUTEX(kvm_lock);
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);
 
struct dentry *kvm_debugfs_dir;
EXPORT_SYMBOL_GPL(kvm_debugfs_dir);
 
static const struct file_operations stat_fops_per_vm;
 
static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
               unsigned long arg);
#ifdef CONFIG_KVM_COMPAT
static long kvm_vcpu_compat_ioctl(struct file *file, unsigned int ioctl,
                  unsigned long arg);
#define KVM_COMPAT(c)   .compat_ioctl   = (c)
#else
/*
 * For architectures that don't implement a compat infrastructure,
 * adopt a double line of defense:
 * - Prevent a compat task from opening /dev/kvm
 * - If the open has been done by a 64bit task, and the KVM fd
 *   passed to a compat task, let the ioctls fail.
 */
static long kvm_no_compat_ioctl(struct file *file, unsigned int ioctl,
                unsigned long arg) { return -EINVAL; }
 
static int kvm_no_compat_open(struct inode *inode, struct file *file)
{
    return is_compat_task() ? -ENODEV : 0;
}
#define KVM_COMPAT(c)   .compat_ioctl   = kvm_no_compat_ioctl,  \
            .open       = kvm_no_compat_open
#endif
static int hardware_enable_all(void);
static void hardware_disable_all(void);
 
static void kvm_io_bus_destroy(struct kvm_io_bus *bus);
 
#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_except(struct kvm *kvm, unsigned int req,
                      struct kvm_vcpu *except)
{
    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) {
        if (vcpu == except)
            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)
{
    return kvm_make_all_cpus_request_except(kvm, req, NULL);
}
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)
{
    gfp_flags |= mc->gfp_zero;
 
    if (mc->kmem_cache)
        return kmem_cache_alloc(mc->kmem_cache, gfp_flags);
    else
        return (void *)__get_free_page(gfp_flags);
}
 
int __kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int 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;
 
        mc->objects = kvmalloc_array(sizeof(void *), capacity, 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)
 
static const union kvm_mmu_notifier_arg KVM_MMU_NOTIFIER_NO_ARG;
 
/* 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))
                    break;
            }
            r.ret |= range->handler(kvm, &gfn_range);
        }
    }
 
    if (range->flush_on_ret && r.ret)
        kvm_flush_remote_tlbs(kvm);
 
    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,
                        union kvm_mmu_notifier_arg arg,
                        gfn_handler_t handler)
{
    struct kvm *kvm = mmu_notifier_to_kvm(mn);
    const struct kvm_mmu_notifier_range range = {
        .start      = start,
        .end        = end,
        .arg        = arg,
        .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;
}
 
static bool kvm_change_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
{
    /*
     * Skipping invalid memslots is correct if and only change_pte() is
     * surrounded by invalidate_range_{start,end}(), which is currently
     * guaranteed by the primary MMU.  If that ever changes, KVM needs to
     * unmap the memslot instead of skipping the memslot to ensure that KVM
     * doesn't hold references to the old PFN.
     */
    WARN_ON_ONCE(!READ_ONCE(kvm->mn_active_invalidate_count));
 
    if (range->slot->flags & KVM_MEMSLOT_INVALID)
        return false;
 
    return kvm_set_spte_gfn(kvm, range);
}
 
static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn,
                    struct mm_struct *mm,
                    unsigned long address,
                    pte_t pte)
{
    struct kvm *kvm = mmu_notifier_to_kvm(mn);
    const union kvm_mmu_notifier_arg arg = { .pte = pte };
 
    trace_kvm_set_spte_hva(address);
 
    /*
     * .change_pte() must be surrounded by .invalidate_range_{start,end}().
     * If mmu_invalidate_in_progress is zero, then no in-progress
     * invalidations, including this one, found a relevant memslot at
     * start(); rechecking memslots here is unnecessary.  Note, a false
     * positive (count elevated by a different invalidation) is sub-optimal
     * but functionally ok.
     */
    WARN_ON_ONCE(!READ_ONCE(kvm->mn_active_invalidate_count));
    if (!READ_ONCE(kvm->mmu_invalidate_in_progress))
        return;
 
    kvm_handle_hva_range(mn, address, address + 1, arg, kvm_change_spte_gfn);
}
 
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,
                      hva_range.may_block);
 
    /*
     * 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);
    wake = (--kvm->mn_active_invalidate_count == 0);
    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_MMU_NOTIFIER_NO_ARG,
                    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,
    .change_pte     = kvm_mmu_notifier_change_pte,
    .release        = kvm_mmu_notifier_release,
};
 
static int kvm_init_mmu_notifier(struct kvm *kvm)
{
    kvm->mmu_notifier.ops = &kvm_mmu_notifier_ops;
    return mmu_notifier_register(&kvm->mmu_notifier, current->mm);
}
 
#else  /* !CONFIG_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;
 
    kvfree(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);
    }
 
    ret = kvm_arch_create_vm_debugfs(kvm);
    if (ret)
        goto out_err;
 
    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.
 */
int __weak kvm_arch_create_vm_debugfs(struct kvm *kvm)
{
    return 0;
}
 
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 = -ENOMEM;
    int 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));
 
    if (init_srcu_struct(&kvm->srcu))
        goto out_err_no_srcu;
    if (init_srcu_struct(&kvm->irq_srcu))
        goto out_err_no_irq_srcu;
 
    refcount_set(&kvm->users_count, 1);
    for (i = 0; i < kvm_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]);
    }
 
    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));
    cleanup_srcu_struct(&kvm->irq_srcu);
out_err_no_irq_srcu:
    cleanup_srcu_struct(&kvm->srcu);
out_err_no_srcu:
    kvm_arch_free_vm(kvm);
    mmdrop(current->mm);
    return ERR_PTR(r);
}
 
static void kvm_destroy_devices(struct kvm *kvm)
{
    struct kvm_device *dev, *tmp;
 
    /*
     * We do not need to take the kvm->lock here, because nobody else
     * has a reference to the struct kvm at this point and therefore
     * cannot access the devices list anyhow.
     */
    list_for_each_entry_safe(dev, tmp, &kvm->devices, vm_node) {
        list_del(&dev->vm_node);
        dev->ops->destroy(dev);
    }
}
 
static void kvm_destroy_vm(struct kvm *kvm)
{
    int i;
    struct mm_struct *mm = kvm->mm;
 
    kvm_destroy_pm_notifier(kvm);
    kvm_uevent_notify_change(KVM_EVENT_DESTROY_VM, kvm);
    kvm_destroy_vm_debugfs(kvm);
    kvm_arch_sync_events(kvm);
    mutex_lock(&kvm_lock);
    list_del(&kvm->vm_list);
    mutex_unlock(&kvm_lock);
    kvm_arch_pre_destroy_vm(kvm);
 
    kvm_free_irq_routing(kvm);
    for (i = 0; i < KVM_NR_BUSES; i++) {
        struct kvm_io_bus *bus = kvm_get_bus(kvm, i);
 
        if (bus)
            kvm_io_bus_destroy(bus);
        kvm->buses[i] = NULL;
    }
    kvm_coalesced_mmio_free(kvm);
#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 __KVM_HAVE_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
/*
 * Returns true if _all_ gfns in the range [@start, @end) have attributes
 * matching @attrs.
 */
bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
                     unsigned long attrs)
{
    XA_STATE(xas, &kvm->mem_attr_array, start);
    unsigned long index;
    bool has_attrs;
    void *entry;
 
    rcu_read_lock();
 
    if (!attrs) {
        has_attrs = !xas_find(&xas, end - 1);
        goto out;
    }
 
    has_attrs = true;
    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) != attrs) {
            has_attrs = false;
            break;
        }
    }
 
out:
    rcu_read_unlock();
    return has_attrs;
}
 
static u64 kvm_supported_mem_attributes(struct kvm *kvm)
{
    if (!kvm || kvm_arch_has_private_mem(kvm))
        return KVM_MEMORY_ATTRIBUTE_PRIVATE;
 
    return 0;
}
 
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, 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->vm_mm, addr, &ptep, &ptl);
    if (r) {
        /*
         * get_user_pages fails for VM_IO and VM_PFNMAP vmas and does
         * not call the fault handler, so do it here.
         */
        bool unlocked = false;
        r = fixup_user_fault(current->mm, addr,
                     (write_fault ? FAULT_FLAG_WRITE : 0),
                     &unlocked);
        if (unlocked)
            return -EAGAIN;
        if (r)
            return r;
 
        r = follow_pte(vma->vm_mm, addr, &ptep, &ptl);
        if (r)
            return r;
    }
 
    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 can sleep
 * @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 (addr == KVM_HVA_ERR_RO_BAD) {
        if (writable)
            *writable = false;
        return KVM_PFN_ERR_RO_FAULT;
    }
 
    if (kvm_is_error_hva(addr)) {
        if (writable)
            *writable = false;
        return KVM_PFN_NOSLOT;
    }
 
    /* Do not map writable pfn in the readonly memslot. */
    if (writable && memslot_is_readonly(slot)) {
        *writable = false;
        writable = NULL;
    }
 
    return hva_to_pfn(addr, atomic, 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;
}
 
static int __kvm_read_guest_page(struct kvm_memory_slot *slot, gfn_t gfn,
                 void *data, int offset, int len)
{
    int r;
    unsigned long addr;
 
    addr = gfn_to_hva_memslot_prot(slot, gfn, NULL);
    if (kvm_is_error_hva(addr))
        return -EFAULT;
    r = __copy_from_user(data, (void __user *)addr + offset, len);
    if (r)
        return -EFAULT;
    return 0;
}
 
int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
            int len)
{
    struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
 
    return __kvm_read_guest_page(slot, gfn, data, offset, len);
}
EXPORT_SYMBOL_GPL(kvm_read_guest_page);
 
int kvm_vcpu_read_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, void *data,
                 int offset, int len)
{
    struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
 
    return __kvm_read_guest_page(slot, gfn, data, offset, len);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_page);
 
int kvm_read_guest(struct kvm *kvm, gpa_t gpa, void *data, unsigned long len)
{
    gfn_t gfn = gpa >> PAGE_SHIFT;
    int seg;
    int offset = offset_in_page(gpa);
    int ret;
 
    while ((seg = next_segment(len, offset)) != 0) {
        ret = kvm_read_guest_page(kvm, gfn, data, offset, seg);
        if (ret < 0)
            return ret;
        offset = 0;
        len -= seg;
        data += seg;
        ++gfn;
    }
    return 0;
}
EXPORT_SYMBOL_GPL(kvm_read_guest);
 
int kvm_vcpu_read_guest(struct kvm_vcpu *vcpu, gpa_t gpa, void *data, unsigned long len)
{
    gfn_t gfn = gpa >> PAGE_SHIFT;
    int seg;
    int offset = offset_in_page(gpa);
    int ret;
 
    while ((seg = next_segment(len, offset)) != 0) {
        ret = kvm_vcpu_read_guest_page(vcpu, gfn, data, offset, seg);
        if (ret < 0)
            return ret;
        offset = 0;
        len -= seg;
        data += seg;
        ++gfn;
    }
    return 0;
}
EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest);
 
static int __kvm_read_guest_atomic(struct kvm_memory_slot *slot, gfn_t gfn,
                       void *data, int offset, unsigned long len)
{
    int r;
    unsigned long addr;
 
    addr = gfn_to_hva_memslot_prot(slot, gfn, NULL);
    if (kvm_is_error_hva(addr))
        return -EFAULT;
    pagefault_disable();
    r = __copy_from_user_inatomic(data, (void __user *)addr + offset, len);
    pagefault_enable();
    if (r)
        return -EFAULT;
    return 0;
}
 
int kvm_vcpu_read_guest_atomic(struct kvm_vcpu *vcpu, gpa_t gpa,
                   void *data, unsigned long len)
{
    gfn_t gfn = gpa >> PAGE_SHIFT;
    struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
    int offset = offset_in_page(gpa);
 
    return __kvm_read_guest_atomic(slot, gfn, data, offset, len);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_atomic);
 
static int __kvm_write_guest_page(struct kvm *kvm,
                  struct kvm_memory_slot *memslot, gfn_t gfn,
                      const void *data, int offset, int len)
{
    int r;
    unsigned long addr;
 
    addr = gfn_to_hva_memslot(memslot, gfn);
    if (kvm_is_error_hva(addr))
        return -EFAULT;
    r = __copy_to_user((void __user *)addr + offset, data, len);
    if (r)
        return -EFAULT;
    mark_page_dirty_in_slot(kvm, memslot, gfn);
    return 0;
}
 
int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn,
             const void *data, int offset, int len)
{
    struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
 
    return __kvm_write_guest_page(kvm, slot, gfn, data, offset, len);
}
EXPORT_SYMBOL_GPL(kvm_write_guest_page);
 
int kvm_vcpu_write_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn,
                  const void *data, int offset, int len)
{
    struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
 
    return __kvm_write_guest_page(vcpu->kvm, slot, gfn, data, offset, len);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_write_guest_page);
 
int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data,
            unsigned long len)
{
    gfn_t gfn = gpa >> PAGE_SHIFT;
    int seg;
    int offset = offset_in_page(gpa);
    int ret;
 
    while ((seg = next_segment(len, offset)) != 0) {
        ret = kvm_write_guest_page(kvm, gfn, data, offset, seg);
        if (ret < 0)
            return ret;
        offset = 0;
        len -= seg;
        data += seg;
        ++gfn;
    }
    return 0;
}
EXPORT_SYMBOL_GPL(kvm_write_guest);
 
int kvm_vcpu_write_guest(struct kvm_vcpu *vcpu, gpa_t gpa, const void *data,
                 unsigned long len)
{
    gfn_t gfn = gpa >> PAGE_SHIFT;
    int seg;
    int offset = offset_in_page(gpa);
    int ret;
 
    while ((seg = next_segment(len, offset)) != 0) {
        ret = kvm_vcpu_write_guest_page(vcpu, gfn, data, offset, seg);
        if (ret < 0)
            return ret;
        offset = 0;
        len -= seg;
        data += seg;
        ++gfn;
    }
    return 0;
}
EXPORT_SYMBOL_GPL(kvm_vcpu_write_guest);
 
static int __kvm_gfn_to_hva_cache_init(struct kvm_memslots *slots,
                       struct gfn_to_hva_cache *ghc,
                       gpa_t gpa, unsigned long len)
{
    int offset = offset_in_page(gpa);
    gfn_t start_gfn = gpa >> PAGE_SHIFT;
    gfn_t end_gfn = (gpa + len - 1) >> PAGE_SHIFT;
    gfn_t nr_pages_needed = end_gfn - start_gfn + 1;
    gfn_t nr_pages_avail;
 
    /* Update ghc->generation before performing any error checks. */
    ghc->generation = slots->generation;
 
    if (start_gfn > end_gfn) {
        ghc->hva = KVM_HVA_ERR_BAD;
        return -EINVAL;
    }
 
    /*
     * If the requested region crosses two memslots, we still
     * verify that the entire region is valid here.
     */
    for ( ; start_gfn <= end_gfn; start_gfn += nr_pages_avail) {
        ghc->memslot = __gfn_to_memslot(slots, start_gfn);
        ghc->hva = gfn_to_hva_many(ghc->memslot, start_gfn,
                       &nr_pages_avail);
        if (kvm_is_error_hva(ghc->hva))
            return -EFAULT;
    }
 
    /* Use the slow path for cross page reads and writes. */
    if (nr_pages_needed == 1)
        ghc->hva += offset;
    else
        ghc->memslot = NULL;
 
    ghc->gpa = gpa;
    ghc->len = len;
    return 0;
}
 
int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
                  gpa_t gpa, unsigned long len)
{
    struct kvm_memslots *slots = kvm_memslots(kvm);
    return __kvm_gfn_to_hva_cache_init(slots, ghc, gpa, len);
}
EXPORT_SYMBOL_GPL(kvm_gfn_to_hva_cache_init);
 
int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
                  void *data, unsigned int offset,
                  unsigned long len)
{
    struct kvm_memslots *slots = kvm_memslots(kvm);
    int r;
    gpa_t gpa = ghc->gpa + offset;
 
    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;
}
 
bool __weak kvm_arch_dy_has_pending_interrupt(struct kvm_vcpu *vcpu)
{
    return false;
}
 
void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode)
{
    struct kvm *kvm = me->kvm;
    struct kvm_vcpu *vcpu;
    int last_boosted_vcpu = me->kvm->last_boosted_vcpu;
    unsigned long i;
    int yielded = 0;
    int try = 3;
    int pass;
 
    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;
            if (READ_ONCE(vcpu->preempted) && yield_to_kernel_mode &&
                !kvm_arch_dy_has_pending_interrupt(vcpu) &&
                !kvm_arch_vcpu_in_kernel(vcpu))
                continue;
            if (!kvm_vcpu_eligible_for_directed_yield(vcpu))
                continue;
 
            yielded = kvm_vcpu_yield_to(vcpu);
            if (yielded > 0) {
                kvm->last_boosted_vcpu = i;
                break;
            } else if (yielded < 0) {
                try--;
                if (!try)
                    break;
            }
        }
    }
    kvm_vcpu_set_in_spin_loop(me, false);
 
    /* Ensure vcpu is not eligible during next spinloop */
    kvm_vcpu_set_dy_eligible(me, false);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_on_spin);
 
static bool kvm_page_in_dirty_ring(struct kvm *kvm, unsigned long pgoff)
{
#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, u32 id)
{
    int r;
    struct kvm_vcpu *vcpu;
    struct page *page;
 
    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;
}
 
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);
        }
        r = kvm_arch_vcpu_ioctl_run(vcpu);
        trace_kvm_userspace_exit(vcpu->run->exit_reason, r);
        break;
    }
    case KVM_GET_REGS: {
        struct kvm_regs *kvm_regs;
 
        r = -ENOMEM;
        kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL_ACCOUNT);
        if (!kvm_regs)
            goto out;
        r = kvm_arch_vcpu_ioctl_get_regs(vcpu, kvm_regs);
        if (r)
            goto out_free1;
        r = -EFAULT;
        if (copy_to_user(argp, kvm_regs, sizeof(struct kvm_regs)))
            goto out_free1;
        r = 0;
out_free1:
        kfree(kvm_regs);
        break;
    }
    case KVM_SET_REGS: {
        struct kvm_regs *kvm_regs;
 
        kvm_regs = memdup_user(argp, sizeof(*kvm_regs));
        if (IS_ERR(kvm_regs)) {
            r = PTR_ERR(kvm_regs);
            goto out;
        }
        r = kvm_arch_vcpu_ioctl_set_regs(vcpu, kvm_regs);
        kfree(kvm_regs);
        break;
    }
    case KVM_GET_SREGS: {
        kvm_sregs = kzalloc(sizeof(struct kvm_sregs),
                    GFP_KERNEL_ACCOUNT);
        r = -ENOMEM;
        if (!kvm_sregs)
            goto out;
        r = kvm_arch_vcpu_ioctl_get_sregs(vcpu, kvm_sregs);
        if (r)
            goto out;
        r = -EFAULT;
        if (copy_to_user(argp, kvm_sregs, sizeof(struct kvm_sregs)))
            goto out;
        r = 0;
        break;
    }
    case KVM_SET_SREGS: {
        kvm_sregs = memdup_user(argp, sizeof(*kvm_sregs));
        if (IS_ERR(kvm_sregs)) {
            r = PTR_ERR(kvm_sregs);
            kvm_sregs = NULL;
            goto out;
        }
        r = kvm_arch_vcpu_ioctl_set_sregs(vcpu, kvm_sregs);
        break;
    }
    case KVM_GET_MP_STATE: {
        struct kvm_mp_state mp_state;
 
        r = kvm_arch_vcpu_ioctl_get_mpstate(vcpu, &mp_state);
        if (r)
            goto out;
        r = -EFAULT;
        if (copy_to_user(argp, &mp_state, sizeof(mp_state)))
            goto out;
        r = 0;
        break;
    }
    case KVM_SET_MP_STATE: {
        struct kvm_mp_state mp_state;
 
        r = -EFAULT;
        if (copy_from_user(&mp_state, argp, sizeof(mp_state)))
            goto out;
        r = kvm_arch_vcpu_ioctl_set_mpstate(vcpu, &mp_state);
        break;
    }
    case KVM_TRANSLATE: {
        struct kvm_translation tr;
 
        r = -EFAULT;
        if (copy_from_user(&tr, argp, sizeof(tr)))
            goto out;
        r = kvm_arch_vcpu_ioctl_translate(vcpu, &tr);
        if (r)
            goto out;
        r = -EFAULT;
        if (copy_to_user(argp, &tr, sizeof(tr)))
            goto out;
        r = 0;
        break;
    }
    case KVM_SET_GUEST_DEBUG: {
        struct kvm_guest_debug dbg;
 
        r = -EFAULT;
        if (copy_from_user(&dbg, argp, sizeof(dbg)))
            goto out;
        r = kvm_arch_vcpu_ioctl_set_guest_debug(vcpu, &dbg);
        break;
    }
    case KVM_SET_SIGNAL_MASK: {
        struct kvm_signal_mask __user *sigmask_arg = argp;
        struct kvm_signal_mask kvm_sigmask;
        sigset_t sigset, *p;
 
        p = NULL;
        if (argp) {
            r = -EFAULT;
            if (copy_from_user(&kvm_sigmask, argp,
                       sizeof(kvm_sigmask)))
                goto out;
            r = -EINVAL;
            if (kvm_sigmask.len != sizeof(sigset))
                goto out;
            r = -EFAULT;
            if (copy_from_user(&sigset, sigmask_arg->sigset,
                       sizeof(sigset)))
                goto out;
            p = &sigset;
        }
        r = kvm_vcpu_ioctl_set_sigmask(vcpu, p);
        break;
    }
    case KVM_GET_FPU: {
        fpu = kzalloc(sizeof(struct kvm_fpu), GFP_KERNEL_ACCOUNT);
        r = -ENOMEM;
        if (!fpu)
            goto out;
        r = kvm_arch_vcpu_ioctl_get_fpu(vcpu, fpu);
        if (r)
            goto out;
        r = -EFAULT;
        if (copy_to_user(argp, fpu, sizeof(struct kvm_fpu)))
            goto out;
        r = 0;
        break;
    }
    case KVM_SET_FPU: {
        fpu = memdup_user(argp, sizeof(*fpu));
        if (IS_ERR(fpu)) {
            r = PTR_ERR(fpu);
            fpu = NULL;
            goto out;
        }
        r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, fpu);
        break;
    }
    case KVM_GET_STATS_FD: {
        r = kvm_vcpu_ioctl_get_stats_fd(vcpu);
        break;
    }
    default:
        r = kvm_arch_vcpu_ioctl(filp, ioctl, arg);
    }
out:
    mutex_unlock(&vcpu->mutex);
    kfree(fpu);
    kfree(kvm_sregs);
    return r;
}
 
#ifdef CONFIG_KVM_COMPAT
static long kvm_vcpu_compat_ioctl(struct file *filp,
                  unsigned int ioctl, unsigned long arg)
{
    struct kvm_vcpu *vcpu = filp->private_data;
    void __user *argp = compat_ptr(arg);
    int r;
 
    if (vcpu->kvm->mm != current->mm || 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(&dev->vm_node);
        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(&dev->vm_node, &kvm->devices);
    mutex_unlock(&kvm->lock);
 
    if (ops->init)
        ops->init(dev);
 
    kvm_get_kvm(kvm);
    ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC);
    if (ret < 0) {
        kvm_put_kvm_no_destroy(kvm);
        mutex_lock(&kvm->lock);
        list_del(&dev->vm_node);
        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_ACCOUNT);
    if (!env)
        return;
 
    add_uevent_var(env, "CREATED=%llu", created);
    add_uevent_var(env, "COUNT=%llu", active);
 
    if (type == KVM_EVENT_CREATE_VM) {
        add_uevent_var(env, "EVENT=create");
        kvm->userspace_pid = task_pid_nr(current);
    } else if (type == KVM_EVENT_DESTROY_VM) {
        add_uevent_var(env, "EVENT=destroy");
    }
    add_uevent_var(env, "PID=%d", kvm->userspace_pid);
 
    if (!IS_ERR(kvm->debugfs_dentry)) {
        char *tmp, *p = kmalloc(PATH_MAX, GFP_KERNEL_ACCOUNT);
 
        if (p) {
            tmp = dentry_path_raw(kvm->debugfs_dentry, p, PATH_MAX);
            if (!IS_ERR(tmp))
                add_uevent_var(env, "STATS_PATH=%s", tmp);
            kfree(p);
        }
    }
    /* no need for checks, since we are adding at most only 5 keys */
    env->envp[env->envp_idx++] = NULL;
    kobject_uevent_env(&kvm_dev.this_device->kobj, KOBJ_CHANGE, env->envp);
    kfree(env);
}
 
static void kvm_init_debug(void)
{
    const struct file_operations *fops;
    const struct _kvm_stats_desc *pdesc;
    int i;
 
    kvm_debugfs_dir = debugfs_create_dir("kvm", NULL);
 
    for (i = 0; i < kvm_vm_stats_header.num_desc; ++i) {
        pdesc = &kvm_vm_stats_desc[i];
        if (kvm_stats_debugfs_mode(pdesc) & 0222)
            fops = &vm_stat_fops;
        else
            fops = &vm_stat_readonly_fops;
        debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
                kvm_debugfs_dir,
                (void *)(long)pdesc->desc.offset, fops);
    }
 
    for (i = 0; i < kvm_vcpu_stats_header.num_desc; ++i) {
        pdesc = &kvm_vcpu_stats_desc[i];
        if (kvm_stats_debugfs_mode(pdesc) & 0222)
            fops = &vcpu_stat_fops;
        else
            fops = &vcpu_stat_readonly_fops;
        debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
                kvm_debugfs_dir,
                (void *)(long)pdesc->desc.offset, fops);
    }
}
 
static inline
struct kvm_vcpu *preempt_notifier_to_vcpu(struct preempt_notifier *pn)
{
    return container_of(pn, struct kvm_vcpu, preempt_notifier);
}
 
static void kvm_sched_in(struct preempt_notifier *pn, int cpu)
{
    struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);
 
    WRITE_ONCE(vcpu->preempted, false);
    WRITE_ONCE(vcpu->ready, false);
 
    __this_cpu_write(kvm_running_vcpu, vcpu);
    kvm_arch_sched_in(vcpu, cpu);
    kvm_arch_vcpu_load(vcpu, cpu);
}
 
static void kvm_sched_out(struct preempt_notifier *pn,
              struct task_struct *next)
{
    struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);
 
    if (current->on_rq) {
        WRITE_ONCE(vcpu->preempted, true);
        WRITE_ONCE(vcpu->ready, true);
    }
    kvm_arch_vcpu_put(vcpu);
    __this_cpu_write(kvm_running_vcpu, NULL);
}
 
/**
 * kvm_get_running_vcpu - get the vcpu running on the current CPU.
 *
 * We can disable preemption locally around accessing the per-CPU variable,
 * and use the resolved vcpu pointer after enabling preemption again,
 * because even if the current thread is migrated to another CPU, reading
 * the per-CPU value later will give us the same value as we update the
 * per-CPU variable in the preempt notifier handlers.
 */
struct kvm_vcpu *kvm_get_running_vcpu(void)
{
    struct kvm_vcpu *vcpu;
 
    preempt_disable();
    vcpu = __this_cpu_read(kvm_running_vcpu);
    preempt_enable();
 
    return vcpu;
}
EXPORT_SYMBOL_GPL(kvm_get_running_vcpu);
 
/**
 * kvm_get_running_vcpus - get the per-CPU array of currently running vcpus.
 */
struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void)
{
        return &kvm_running_vcpu;
}
 
#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;
}