Adding upstream version 5.10.209.upstream/5.10.209

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 5179 insertions, 0 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
new file mode 100644
index 000000000..356fd5d1a
--- /dev/null
+++ b/virt/kvm/kvm_main.c
@@ -0,0 +1,5179 @@
+// 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 <asm/processor.h>
+#include <asm/ioctl.h>
+#include <linux/uaccess.h>
+
+#include "coalesced_mmio.h"
+#include "async_pf.h"
+#include "vfio.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/kvm.h>
+
+/* Worst case buffer size needed for holding an integer. */
+#define ITOA_MAX_LEN 12
+
+MODULE_AUTHOR("Qumranet");
+MODULE_LICENSE("GPL");
+
+/* Architectures should define their poll value according to the halt latency */
+unsigned int halt_poll_ns = KVM_HALT_POLL_NS_DEFAULT;
+module_param(halt_poll_ns, uint, 0644);
+EXPORT_SYMBOL_GPL(halt_poll_ns);
+
+/* Default doubles per-vcpu halt_poll_ns. */
+unsigned int halt_poll_ns_grow = 2;
+module_param(halt_poll_ns_grow, uint, 0644);
+EXPORT_SYMBOL_GPL(halt_poll_ns_grow);
+
+/* The start value to grow halt_poll_ns from */
+unsigned int halt_poll_ns_grow_start = 10000; /* 10us */
+module_param(halt_poll_ns_grow_start, uint, 0644);
+EXPORT_SYMBOL_GPL(halt_poll_ns_grow_start);
+
+/* Default resets per-vcpu halt_poll_ns . */
+unsigned int halt_poll_ns_shrink;
+module_param(halt_poll_ns_shrink, uint, 0644);
+EXPORT_SYMBOL_GPL(halt_poll_ns_shrink);
+
+/*
+ * Ordering of locks:
+ *
+ *	kvm->lock --> kvm->slots_lock --> kvm->irq_lock
+ */
+
+DEFINE_MUTEX(kvm_lock);
+static DEFINE_RAW_SPINLOCK(kvm_count_lock);
+LIST_HEAD(vm_list);
+
+static cpumask_var_t cpus_hardware_enabled;
+static int kvm_usage_count;
+static atomic_t hardware_enable_failed;
+
+static struct kmem_cache *kvm_vcpu_cache;
+
+static __read_mostly struct preempt_ops kvm_preempt_ops;
+static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_running_vcpu);
+
+struct dentry *kvm_debugfs_dir;
+EXPORT_SYMBOL_GPL(kvm_debugfs_dir);
+
+static int kvm_debugfs_num_entries;
+static const struct file_operations stat_fops_per_vm;
+
+static struct file_operations kvm_chardev_ops;
+
+static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
+			   unsigned long arg);
+#ifdef CONFIG_KVM_COMPAT
+static long kvm_vcpu_compat_ioctl(struct file *file, unsigned int ioctl,
+				  unsigned long arg);
+#define KVM_COMPAT(c)	.compat_ioctl	= (c)
+#else
+/*
+ * For architectures that don't implement a compat infrastructure,
+ * adopt a double line of defense:
+ * - Prevent a compat task from opening /dev/kvm
+ * - If the open has been done by a 64bit task, and the KVM fd
+ *   passed to a compat task, let the ioctls fail.
+ */
+static long kvm_no_compat_ioctl(struct file *file, unsigned int ioctl,
+				unsigned long arg) { return -EINVAL; }
+
+static int kvm_no_compat_open(struct inode *inode, struct file *file)
+{
+	return is_compat_task() ? -ENODEV : 0;
+}
+#define KVM_COMPAT(c)	.compat_ioctl	= kvm_no_compat_ioctl,	\
+			.open		= kvm_no_compat_open
+#endif
+static int hardware_enable_all(void);
+static void hardware_disable_all(void);
+
+static void kvm_io_bus_destroy(struct kvm_io_bus *bus);
+
+__visible bool kvm_rebooting;
+EXPORT_SYMBOL_GPL(kvm_rebooting);
+
+#define KVM_EVENT_CREATE_VM 0
+#define KVM_EVENT_DESTROY_VM 1
+static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm);
+static unsigned long long kvm_createvm_count;
+static unsigned long long kvm_active_vms;
+
+static DEFINE_PER_CPU(cpumask_var_t, cpu_kick_mask);
+
+__weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
+						   unsigned long start, unsigned long end)
+{
+}
+
+__weak void kvm_arch_guest_memory_reclaimed(struct kvm *kvm)
+{
+}
+
+bool kvm_is_zone_device_pfn(kvm_pfn_t pfn)
+{
+	/*
+	 * The metadata used by is_zone_device_page() to determine whether or
+	 * not a page is ZONE_DEVICE is guaranteed to be valid if and only if
+	 * the device has been pinned, e.g. by get_user_pages().  WARN if the
+	 * page_count() is zero to help detect bad usage of this helper.
+	 */
+	if (!pfn_valid(pfn) || WARN_ON_ONCE(!page_count(pfn_to_page(pfn))))
+		return false;
+
+	return is_zone_device_page(pfn_to_page(pfn));
+}
+
+bool kvm_is_reserved_pfn(kvm_pfn_t pfn)
+{
+	/*
+	 * ZONE_DEVICE pages currently set PG_reserved, but from a refcounting
+	 * perspective they are "normal" pages, albeit with slightly different
+	 * usage rules.
+	 */
+	if (pfn_valid(pfn))
+		return PageReserved(pfn_to_page(pfn)) &&
+		       !is_zero_pfn(pfn) &&
+		       !kvm_is_zone_device_pfn(pfn);
+
+	return true;
+}
+
+bool kvm_is_transparent_hugepage(kvm_pfn_t pfn)
+{
+	struct page *page = pfn_to_page(pfn);
+
+	if (!PageTransCompoundMap(page))
+		return false;
+
+	return is_transparent_hugepage(compound_head(page));
+}
+
+/*
+ * Switches to specified vcpu, until a matching vcpu_put()
+ */
+void vcpu_load(struct kvm_vcpu *vcpu)
+{
+	int cpu = get_cpu();
+
+	__this_cpu_write(kvm_running_vcpu, vcpu);
+	preempt_notifier_register(&vcpu->preempt_notifier);
+	kvm_arch_vcpu_load(vcpu, cpu);
+	put_cpu();
+}
+EXPORT_SYMBOL_GPL(vcpu_load);
+
+void vcpu_put(struct kvm_vcpu *vcpu)
+{
+	preempt_disable();
+	kvm_arch_vcpu_put(vcpu);
+	preempt_notifier_unregister(&vcpu->preempt_notifier);
+	__this_cpu_write(kvm_running_vcpu, NULL);
+	preempt_enable();
+}
+EXPORT_SYMBOL_GPL(vcpu_put);
+
+/* TODO: merge with kvm_arch_vcpu_should_kick */
+static bool kvm_request_needs_ipi(struct kvm_vcpu *vcpu, unsigned req)
+{
+	int mode = kvm_vcpu_exiting_guest_mode(vcpu);
+
+	/*
+	 * We need to wait for the VCPU to reenable interrupts and get out of
+	 * READING_SHADOW_PAGE_TABLES mode.
+	 */
+	if (req & KVM_REQUEST_WAIT)
+		return mode != OUTSIDE_GUEST_MODE;
+
+	/*
+	 * Need to kick a running VCPU, but otherwise there is nothing to do.
+	 */
+	return mode == IN_GUEST_MODE;
+}
+
+static void ack_flush(void *_completed)
+{
+}
+
+static inline bool kvm_kick_many_cpus(cpumask_var_t tmp, bool wait)
+{
+	const struct cpumask *cpus;
+
+	if (likely(cpumask_available(tmp)))
+		cpus = tmp;
+	else
+		cpus = cpu_online_mask;
+
+	if (cpumask_empty(cpus))
+		return false;
+
+	smp_call_function_many(cpus, ack_flush, NULL, wait);
+	return true;
+}
+
+static void kvm_make_vcpu_request(struct kvm *kvm, struct kvm_vcpu *vcpu,
+				  unsigned int req, cpumask_var_t tmp,
+				  int current_cpu)
+{
+	int cpu;
+
+	kvm_make_request(req, vcpu);
+
+	if (!(req & KVM_REQUEST_NO_WAKEUP) && kvm_vcpu_wake_up(vcpu))
+		return;
+
+	/*
+	 * tmp can be "unavailable" if cpumasks are allocated off stack as
+	 * allocation of the mask is deliberately not fatal and is handled by
+	 * falling back to kicking all online CPUs.
+	 */
+	if (!cpumask_available(tmp))
+		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,
+				 struct kvm_vcpu *except,
+				 unsigned long *vcpu_bitmap, cpumask_var_t tmp)
+{
+	struct kvm_vcpu *vcpu;
+	int i, me;
+	bool called;
+
+	me = get_cpu();
+
+	for_each_set_bit(i, vcpu_bitmap, KVM_MAX_VCPUS) {
+		vcpu = kvm_get_vcpu(kvm, i);
+		if (!vcpu || vcpu == except)
+			continue;
+		kvm_make_vcpu_request(kvm, vcpu, req, tmp, me);
+	}
+
+	called = kvm_kick_many_cpus(tmp, !!(req & KVM_REQUEST_WAIT));
+	put_cpu();
+
+	return called;
+}
+
+bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req,
+				      struct kvm_vcpu *except)
+{
+	struct kvm_vcpu *vcpu;
+	struct cpumask *cpus;
+	bool called;
+	int i, 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(kvm, 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);
+}
+
+#ifndef CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL
+void kvm_flush_remote_tlbs(struct kvm *kvm)
+{
+	/*
+	 * Read tlbs_dirty before setting KVM_REQ_TLB_FLUSH in
+	 * kvm_make_all_cpus_request.
+	 */
+	long dirty_count = smp_load_acquire(&kvm->tlbs_dirty);
+
+	/*
+	 * We want to publish modifications to the page tables before reading
+	 * mode. Pairs with a memory barrier in arch-specific code.
+	 * - x86: smp_mb__after_srcu_read_unlock in vcpu_enter_guest
+	 * and smp_mb in walk_shadow_page_lockless_begin/end.
+	 * - powerpc: smp_mb in kvmppc_prepare_to_enter.
+	 *
+	 * There is already an smp_mb__after_atomic() before
+	 * kvm_make_all_cpus_request() reads vcpu->mode. We reuse that
+	 * barrier here.
+	 */
+	if (!kvm_arch_flush_remote_tlb(kvm)
+	    || kvm_make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH))
+		++kvm->stat.remote_tlb_flush;
+	cmpxchg(&kvm->tlbs_dirty, dirty_count, 0);
+}
+EXPORT_SYMBOL_GPL(kvm_flush_remote_tlbs);
+#endif
+
+void kvm_reload_remote_mmus(struct kvm *kvm)
+{
+	kvm_make_all_cpus_request(kvm, KVM_REQ_MMU_RELOAD);
+}
+
+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 min)
+{
+	void *obj;
+
+	if (mc->nobjs >= min)
+		return 0;
+	while (mc->nobjs < ARRAY_SIZE(mc->objects)) {
+		obj = mmu_memory_cache_alloc_obj(mc, GFP_KERNEL_ACCOUNT);
+		if (!obj)
+			return mc->nobjs >= min ? 0 : -ENOMEM;
+		mc->objects[mc->nobjs++] = obj;
+	}
+	return 0;
+}
+
+int kvm_mmu_memory_cache_nr_free_objects(struct kvm_mmu_memory_cache *mc)
+{
+	return mc->nobjs;
+}
+
+void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
+{
+	while (mc->nobjs) {
+		if (mc->kmem_cache)
+			kmem_cache_free(mc->kmem_cache, mc->objects[--mc->nobjs]);
+		else
+			free_page((unsigned long)mc->objects[--mc->nobjs]);
+	}
+}
+
+void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
+{
+	void *p;
+
+	if (WARN_ON(!mc->nobjs))
+		p = mmu_memory_cache_alloc_obj(mc, GFP_ATOMIC | __GFP_ACCOUNT);
+	else
+		p = mc->objects[--mc->nobjs];
+	BUG_ON(!p);
+	return p;
+}
+#endif
+
+static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
+{
+	mutex_init(&vcpu->mutex);
+	vcpu->cpu = -1;
+	vcpu->kvm = kvm;
+	vcpu->vcpu_id = id;
+	vcpu->pid = NULL;
+	rcuwait_init(&vcpu->wait);
+	kvm_async_pf_vcpu_init(vcpu);
+
+	vcpu->pre_pcpu = -1;
+	INIT_LIST_HEAD(&vcpu->blocked_vcpu_list);
+
+	kvm_vcpu_set_in_spin_loop(vcpu, false);
+	kvm_vcpu_set_dy_eligible(vcpu, false);
+	vcpu->preempted = false;
+	vcpu->ready = false;
+	preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops);
+}
+
+void kvm_vcpu_destroy(struct kvm_vcpu *vcpu)
+{
+	kvm_arch_vcpu_destroy(vcpu);
+
+	/*
+	 * No need for rcu_read_lock as VCPU_RUN is the only place that changes
+	 * the vcpu->pid pointer, and at destruction time all file descriptors
+	 * are already gone.
+	 */
+	put_pid(rcu_dereference_protected(vcpu->pid, 1));
+
+	free_page((unsigned long)vcpu->run);
+	kmem_cache_free(kvm_vcpu_cache, vcpu);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_destroy);
+
+#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
+static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn)
+{
+	return container_of(mn, struct kvm, mmu_notifier);
+}
+
+static void kvm_mmu_notifier_invalidate_range(struct mmu_notifier *mn,
+					      struct mm_struct *mm,
+					      unsigned long start, unsigned long end)
+{
+	struct kvm *kvm = mmu_notifier_to_kvm(mn);
+	int idx;
+
+	idx = srcu_read_lock(&kvm->srcu);
+	kvm_arch_mmu_notifier_invalidate_range(kvm, start, end);
+	srcu_read_unlock(&kvm->srcu, idx);
+}
+
+static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn,
+					struct mm_struct *mm,
+					unsigned long address,
+					pte_t pte)
+{
+	struct kvm *kvm = mmu_notifier_to_kvm(mn);
+	int idx;
+
+	idx = srcu_read_lock(&kvm->srcu);
+	spin_lock(&kvm->mmu_lock);
+	kvm->mmu_notifier_seq++;
+
+	if (kvm_set_spte_hva(kvm, address, pte))
+		kvm_flush_remote_tlbs(kvm);
+
+	spin_unlock(&kvm->mmu_lock);
+	srcu_read_unlock(&kvm->srcu, idx);
+}
+
+static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
+					const struct mmu_notifier_range *range)
+{
+	struct kvm *kvm = mmu_notifier_to_kvm(mn);
+	int need_tlb_flush = 0, idx;
+
+	idx = srcu_read_lock(&kvm->srcu);
+	spin_lock(&kvm->mmu_lock);
+	/*
+	 * The count increase must become visible at unlock time as no
+	 * spte can be established without taking the mmu_lock and
+	 * count is also read inside the mmu_lock critical section.
+	 */
+	kvm->mmu_notifier_count++;
+	need_tlb_flush = kvm_unmap_hva_range(kvm, range->start, range->end,
+					     range->flags);
+	/* we've to flush the tlb before the pages can be freed */
+	if (need_tlb_flush || kvm->tlbs_dirty)
+		kvm_flush_remote_tlbs(kvm);
+
+	spin_unlock(&kvm->mmu_lock);
+	kvm_arch_guest_memory_reclaimed(kvm);
+	srcu_read_unlock(&kvm->srcu, idx);
+
+	return 0;
+}
+
+static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,
+					const struct mmu_notifier_range *range)
+{
+	struct kvm *kvm = mmu_notifier_to_kvm(mn);
+
+	spin_lock(&kvm->mmu_lock);
+	/*
+	 * This sequence increase will notify the kvm page fault that
+	 * the page that is going to be mapped in the spte could have
+	 * been freed.
+	 */
+	kvm->mmu_notifier_seq++;
+	smp_wmb();
+	/*
+	 * The above sequence increase must be visible before the
+	 * below count decrease, which is ensured by the smp_wmb above
+	 * in conjunction with the smp_rmb in mmu_notifier_retry().
+	 */
+	kvm->mmu_notifier_count--;
+	spin_unlock(&kvm->mmu_lock);
+
+	BUG_ON(kvm->mmu_notifier_count < 0);
+}
+
+static int kvm_mmu_notifier_clear_flush_young(struct mmu_notifier *mn,
+					      struct mm_struct *mm,
+					      unsigned long start,
+					      unsigned long end)
+{
+	struct kvm *kvm = mmu_notifier_to_kvm(mn);
+	int young, idx;
+
+	idx = srcu_read_lock(&kvm->srcu);
+	spin_lock(&kvm->mmu_lock);
+
+	young = kvm_age_hva(kvm, start, end);
+	if (young)
+		kvm_flush_remote_tlbs(kvm);
+
+	spin_unlock(&kvm->mmu_lock);
+	srcu_read_unlock(&kvm->srcu, idx);
+
+	return young;
+}
+
+static int kvm_mmu_notifier_clear_young(struct mmu_notifier *mn,
+					struct mm_struct *mm,
+					unsigned long start,
+					unsigned long end)
+{
+	struct kvm *kvm = mmu_notifier_to_kvm(mn);
+	int young, idx;
+
+	idx = srcu_read_lock(&kvm->srcu);
+	spin_lock(&kvm->mmu_lock);
+	/*
+	 * Even though we do not flush TLB, this will still adversely
+	 * affect performance on pre-Haswell Intel EPT, where there is
+	 * no EPT Access Bit to clear so that we have to tear down EPT
+	 * tables instead. If we find this unacceptable, we can always
+	 * add a parameter to kvm_age_hva so that it effectively doesn't
+	 * do anything on clear_young.
+	 *
+	 * Also note that currently we never issue secondary TLB flushes
+	 * from clear_young, leaving this job up to the regular system
+	 * cadence. If we find this inaccurate, we might come up with a
+	 * more sophisticated heuristic later.
+	 */
+	young = kvm_age_hva(kvm, start, end);
+	spin_unlock(&kvm->mmu_lock);
+	srcu_read_unlock(&kvm->srcu, idx);
+
+	return young;
+}
+
+static int kvm_mmu_notifier_test_young(struct mmu_notifier *mn,
+				       struct mm_struct *mm,
+				       unsigned long address)
+{
+	struct kvm *kvm = mmu_notifier_to_kvm(mn);
+	int young, idx;
+
+	idx = srcu_read_lock(&kvm->srcu);
+	spin_lock(&kvm->mmu_lock);
+	young = kvm_test_age_hva(kvm, address);
+	spin_unlock(&kvm->mmu_lock);
+	srcu_read_unlock(&kvm->srcu, idx);
+
+	return young;
+}
+
+static void kvm_mmu_notifier_release(struct mmu_notifier *mn,
+				     struct mm_struct *mm)
+{
+	struct kvm *kvm = mmu_notifier_to_kvm(mn);
+	int idx;
+
+	idx = srcu_read_lock(&kvm->srcu);
+	kvm_flush_shadow_all(kvm);
+	srcu_read_unlock(&kvm->srcu, idx);
+}
+
+static const struct mmu_notifier_ops kvm_mmu_notifier_ops = {
+	.invalidate_range	= kvm_mmu_notifier_invalidate_range,
+	.invalidate_range_start	= kvm_mmu_notifier_invalidate_range_start,
+	.invalidate_range_end	= kvm_mmu_notifier_invalidate_range_end,
+	.clear_flush_young	= kvm_mmu_notifier_clear_flush_young,
+	.clear_young		= kvm_mmu_notifier_clear_young,
+	.test_young		= kvm_mmu_notifier_test_young,
+	.change_pte		= kvm_mmu_notifier_change_pte,
+	.release		= kvm_mmu_notifier_release,
+};
+
+static int kvm_init_mmu_notifier(struct kvm *kvm)
+{
+	kvm->mmu_notifier.ops = &kvm_mmu_notifier_ops;
+	return mmu_notifier_register(&kvm->mmu_notifier, current->mm);
+}
+
+#else  /* !(CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER) */
+
+static int kvm_init_mmu_notifier(struct kvm *kvm)
+{
+	return 0;
+}
+
+#endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */
+
+static struct kvm_memslots *kvm_alloc_memslots(void)
+{
+	int i;
+	struct kvm_memslots *slots;
+
+	slots = kvzalloc(sizeof(struct kvm_memslots), GFP_KERNEL_ACCOUNT);
+	if (!slots)
+		return NULL;
+
+	for (i = 0; i < KVM_MEM_SLOTS_NUM; i++)
+		slots->id_to_index[i] = -1;
+
+	return slots;
+}
+
+static void kvm_destroy_dirty_bitmap(struct kvm_memory_slot *memslot)
+{
+	if (!memslot->dirty_bitmap)
+		return;
+
+	kvfree(memslot->dirty_bitmap);
+	memslot->dirty_bitmap = NULL;
+}
+
+static void kvm_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot)
+{
+	kvm_destroy_dirty_bitmap(slot);
+
+	kvm_arch_free_memslot(kvm, slot);
+
+	slot->flags = 0;
+	slot->npages = 0;
+}
+
+static void kvm_free_memslots(struct kvm *kvm, struct kvm_memslots *slots)
+{
+	struct kvm_memory_slot *memslot;
+
+	if (!slots)
+		return;
+
+	kvm_for_each_memslot(memslot, slots)
+		kvm_free_memslot(kvm, memslot);
+
+	kvfree(slots);
+}
+
+static void kvm_destroy_vm_debugfs(struct kvm *kvm)
+{
+	int i;
+
+	if (!kvm->debugfs_dentry)
+		return;
+
+	debugfs_remove_recursive(kvm->debugfs_dentry);
+
+	if (kvm->debugfs_stat_data) {
+		for (i = 0; i < kvm_debugfs_num_entries; i++)
+			kfree(kvm->debugfs_stat_data[i]);
+		kfree(kvm->debugfs_stat_data);
+	}
+}
+
+static int kvm_create_vm_debugfs(struct kvm *kvm, int fd)
+{
+	static DEFINE_MUTEX(kvm_debugfs_lock);
+	struct dentry *dent;
+	char dir_name[ITOA_MAX_LEN * 2];
+	struct kvm_stat_data *stat_data;
+	struct kvm_stats_debugfs_item *p;
+
+	if (!debugfs_initialized())
+		return 0;
+
+	snprintf(dir_name, sizeof(dir_name), "%d-%d", task_pid_nr(current), fd);
+	mutex_lock(&kvm_debugfs_lock);
+	dent = debugfs_lookup(dir_name, kvm_debugfs_dir);
+	if (dent) {
+		pr_warn_ratelimited("KVM: debugfs: duplicate directory %s\n", dir_name);
+		dput(dent);
+		mutex_unlock(&kvm_debugfs_lock);
+		return 0;
+	}
+	dent = debugfs_create_dir(dir_name, kvm_debugfs_dir);
+	mutex_unlock(&kvm_debugfs_lock);
+	if (IS_ERR(dent))
+		return 0;
+
+	kvm->debugfs_dentry = dent;
+	kvm->debugfs_stat_data = kcalloc(kvm_debugfs_num_entries,
+					 sizeof(*kvm->debugfs_stat_data),
+					 GFP_KERNEL_ACCOUNT);
+	if (!kvm->debugfs_stat_data)
+		return -ENOMEM;
+
+	for (p = debugfs_entries; p->name; p++) {
+		stat_data = kzalloc(sizeof(*stat_data), GFP_KERNEL_ACCOUNT);
+		if (!stat_data)
+			return -ENOMEM;
+
+		stat_data->kvm = kvm;
+		stat_data->dbgfs_item = p;
+		kvm->debugfs_stat_data[p - debugfs_entries] = stat_data;
+		debugfs_create_file(p->name, KVM_DBGFS_GET_MODE(p),
+				    kvm->debugfs_dentry, stat_data,
+				    &stat_fops_per_vm);
+	}
+	return 0;
+}
+
+/*
+ * Called after the VM is otherwise initialized, but just before adding it to
+ * the vm_list.
+ */
+int __weak kvm_arch_post_init_vm(struct kvm *kvm)
+{
+	return 0;
+}
+
+/*
+ * Called just after removing the VM from the vm_list, but before doing any
+ * other destruction.
+ */
+void __weak kvm_arch_pre_destroy_vm(struct kvm *kvm)
+{
+}
+
+static struct kvm *kvm_create_vm(unsigned long type)
+{
+	struct kvm *kvm = kvm_arch_alloc_vm();
+	int r = -ENOMEM;
+	int i;
+
+	if (!kvm)
+		return ERR_PTR(-ENOMEM);
+
+	spin_lock_init(&kvm->mmu_lock);
+	mmgrab(current->mm);
+	kvm->mm = current->mm;
+	kvm_eventfd_init(kvm);
+	mutex_init(&kvm->lock);
+	mutex_init(&kvm->irq_lock);
+	mutex_init(&kvm->slots_lock);
+	INIT_LIST_HEAD(&kvm->devices);
+
+	BUILD_BUG_ON(KVM_MEM_SLOTS_NUM > SHRT_MAX);
+
+	if (init_srcu_struct(&kvm->srcu))
+		goto out_err_no_srcu;
+	if (init_srcu_struct(&kvm->irq_srcu))
+		goto out_err_no_irq_srcu;
+
+	refcount_set(&kvm->users_count, 1);
+	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+		struct kvm_memslots *slots = kvm_alloc_memslots();
+
+		if (!slots)
+			goto out_err_no_arch_destroy_vm;
+		/* Generations must be different for each address space. */
+		slots->generation = i;
+		rcu_assign_pointer(kvm->memslots[i], slots);
+	}
+
+	for (i = 0; i < KVM_NR_BUSES; i++) {
+		rcu_assign_pointer(kvm->buses[i],
+			kzalloc(sizeof(struct kvm_io_bus), GFP_KERNEL_ACCOUNT));
+		if (!kvm->buses[i])
+			goto out_err_no_arch_destroy_vm;
+	}
+
+	kvm->max_halt_poll_ns = halt_poll_ns;
+
+	r = kvm_arch_init_vm(kvm, type);
+	if (r)
+		goto out_err_no_arch_destroy_vm;
+
+	r = hardware_enable_all();
+	if (r)
+		goto out_err_no_disable;
+
+#ifdef CONFIG_HAVE_KVM_IRQFD
+	INIT_HLIST_HEAD(&kvm->irq_ack_notifier_list);
+#endif
+
+	r = kvm_init_mmu_notifier(kvm);
+	if (r)
+		goto out_err_no_mmu_notifier;
+
+	r = kvm_arch_post_init_vm(kvm);
+	if (r)
+		goto out_err;
+
+	mutex_lock(&kvm_lock);
+	list_add(&kvm->vm_list, &vm_list);
+	mutex_unlock(&kvm_lock);
+
+	preempt_notifier_inc();
+
+	/*
+	 * When the fd passed to this ioctl() is opened it pins the module,
+	 * but try_module_get() also prevents getting a reference if the module
+	 * is in MODULE_STATE_GOING (e.g. if someone ran "rmmod --wait").
+	 */
+	if (!try_module_get(kvm_chardev_ops.owner)) {
+		r = -ENODEV;
+		goto out_err;
+	}
+
+	return kvm;
+
+out_err:
+#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
+	if (kvm->mmu_notifier.ops)
+		mmu_notifier_unregister(&kvm->mmu_notifier, current->mm);
+#endif
+out_err_no_mmu_notifier:
+	hardware_disable_all();
+out_err_no_disable:
+	kvm_arch_destroy_vm(kvm);
+out_err_no_arch_destroy_vm:
+	WARN_ON_ONCE(!refcount_dec_and_test(&kvm->users_count));
+	for (i = 0; i < KVM_NR_BUSES; i++)
+		kfree(kvm_get_bus(kvm, i));
+	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++)
+		kvm_free_memslots(kvm, __kvm_memslots(kvm, i));
+	cleanup_srcu_struct(&kvm->irq_srcu);
+out_err_no_irq_srcu:
+	cleanup_srcu_struct(&kvm->srcu);
+out_err_no_srcu:
+	kvm_arch_free_vm(kvm);
+	mmdrop(current->mm);
+	return ERR_PTR(r);
+}
+
+static void kvm_destroy_devices(struct kvm *kvm)
+{
+	struct kvm_device *dev, *tmp;
+
+	/*
+	 * We do not need to take the kvm->lock here, because nobody else
+	 * has a reference to the struct kvm at this point and therefore
+	 * cannot access the devices list anyhow.
+	 */
+	list_for_each_entry_safe(dev, tmp, &kvm->devices, vm_node) {
+		list_del(&dev->vm_node);
+		dev->ops->destroy(dev);
+	}
+}
+
+static void kvm_destroy_vm(struct kvm *kvm)
+{
+	int i;
+	struct mm_struct *mm = kvm->mm;
+
+	kvm_uevent_notify_change(KVM_EVENT_DESTROY_VM, kvm);
+	kvm_destroy_vm_debugfs(kvm);
+	kvm_arch_sync_events(kvm);
+	mutex_lock(&kvm_lock);
+	list_del(&kvm->vm_list);
+	mutex_unlock(&kvm_lock);
+	kvm_arch_pre_destroy_vm(kvm);
+
+	kvm_free_irq_routing(kvm);
+	for (i = 0; i < KVM_NR_BUSES; i++) {
+		struct kvm_io_bus *bus = kvm_get_bus(kvm, i);
+
+		if (bus)
+			kvm_io_bus_destroy(bus);
+		kvm->buses[i] = NULL;
+	}
+	kvm_coalesced_mmio_free(kvm);
+#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
+	mmu_notifier_unregister(&kvm->mmu_notifier, kvm->mm);
+#else
+	kvm_flush_shadow_all(kvm);
+#endif
+	kvm_arch_destroy_vm(kvm);
+	kvm_destroy_devices(kvm);
+	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++)
+		kvm_free_memslots(kvm, __kvm_memslots(kvm, i));
+	cleanup_srcu_struct(&kvm->irq_srcu);
+	cleanup_srcu_struct(&kvm->srcu);
+	kvm_arch_free_vm(kvm);
+	preempt_notifier_dec();
+	hardware_disable_all();
+	mmdrop(mm);
+	module_put(kvm_chardev_ops.owner);
+}
+
+void kvm_get_kvm(struct kvm *kvm)
+{
+	refcount_inc(&kvm->users_count);
+}
+EXPORT_SYMBOL_GPL(kvm_get_kvm);
+
+void kvm_put_kvm(struct kvm *kvm)
+{
+	if (refcount_dec_and_test(&kvm->users_count))
+		kvm_destroy_vm(kvm);
+}
+EXPORT_SYMBOL_GPL(kvm_put_kvm);
+
+/*
+ * Used to put a reference that was taken on behalf of an object associated
+ * with a user-visible file descriptor, e.g. a vcpu or device, if installation
+ * of the new file descriptor fails and the reference cannot be transferred to
+ * its final owner.  In such cases, the caller is still actively using @kvm and
+ * will fail miserably if the refcount unexpectedly hits zero.
+ */
+void kvm_put_kvm_no_destroy(struct kvm *kvm)
+{
+	WARN_ON(refcount_dec_and_test(&kvm->users_count));
+}
+EXPORT_SYMBOL_GPL(kvm_put_kvm_no_destroy);
+
+static int kvm_vm_release(struct inode *inode, struct file *filp)
+{
+	struct kvm *kvm = filp->private_data;
+
+	kvm_irqfd_release(kvm);
+
+	kvm_put_kvm(kvm);
+	return 0;
+}
+
+/*
+ * Allocation size is twice as large as the actual dirty bitmap size.
+ * See kvm_vm_ioctl_get_dirty_log() why this is needed.
+ */
+static int kvm_alloc_dirty_bitmap(struct kvm_memory_slot *memslot)
+{
+	unsigned long dirty_bytes = 2 * kvm_dirty_bitmap_bytes(memslot);
+
+	memslot->dirty_bitmap = kvzalloc(dirty_bytes, GFP_KERNEL_ACCOUNT);
+	if (!memslot->dirty_bitmap)
+		return -ENOMEM;
+
+	return 0;
+}
+
+/*
+ * Delete a memslot by decrementing the number of used slots and shifting all
+ * other entries in the array forward one spot.
+ */
+static inline void kvm_memslot_delete(struct kvm_memslots *slots,
+				      struct kvm_memory_slot *memslot)
+{
+	struct kvm_memory_slot *mslots = slots->memslots;
+	int i;
+
+	if (WARN_ON(slots->id_to_index[memslot->id] == -1))
+		return;
+
+	slots->used_slots--;
+
+	if (atomic_read(&slots->lru_slot) >= slots->used_slots)
+		atomic_set(&slots->lru_slot, 0);
+
+	for (i = slots->id_to_index[memslot->id]; i < slots->used_slots; i++) {
+		mslots[i] = mslots[i + 1];
+		slots->id_to_index[mslots[i].id] = i;
+	}
+	mslots[i] = *memslot;
+	slots->id_to_index[memslot->id] = -1;
+}
+
+/*
+ * "Insert" a new memslot by incrementing the number of used slots.  Returns
+ * the new slot's initial index into the memslots array.
+ */
+static inline int kvm_memslot_insert_back(struct kvm_memslots *slots)
+{
+	return slots->used_slots++;
+}
+
+/*
+ * Move a changed memslot backwards in the array by shifting existing slots
+ * with a higher GFN toward the front of the array.  Note, the changed memslot
+ * itself is not preserved in the array, i.e. not swapped at this time, only
+ * its new index into the array is tracked.  Returns the changed memslot's
+ * current index into the memslots array.
+ */
+static inline int kvm_memslot_move_backward(struct kvm_memslots *slots,
+					    struct kvm_memory_slot *memslot)
+{
+	struct kvm_memory_slot *mslots = slots->memslots;
+	int i;
+
+	if (WARN_ON_ONCE(slots->id_to_index[memslot->id] == -1) ||
+	    WARN_ON_ONCE(!slots->used_slots))
+		return -1;
+
+	/*
+	 * Move the target memslot backward in the array by shifting existing
+	 * memslots with a higher GFN (than the target memslot) towards the
+	 * front of the array.
+	 */
+	for (i = slots->id_to_index[memslot->id]; i < slots->used_slots - 1; i++) {
+		if (memslot->base_gfn > mslots[i + 1].base_gfn)
+			break;
+
+		WARN_ON_ONCE(memslot->base_gfn == mslots[i + 1].base_gfn);
+
+		/* Shift the next memslot forward one and update its index. */
+		mslots[i] = mslots[i + 1];
+		slots->id_to_index[mslots[i].id] = i;
+	}
+	return i;
+}
+
+/*
+ * Move a changed memslot forwards in the array by shifting existing slots with
+ * a lower GFN toward the back of the array.  Note, the changed memslot itself
+ * is not preserved in the array, i.e. not swapped at this time, only its new
+ * index into the array is tracked.  Returns the changed memslot's final index
+ * into the memslots array.
+ */
+static inline int kvm_memslot_move_forward(struct kvm_memslots *slots,
+					   struct kvm_memory_slot *memslot,
+					   int start)
+{
+	struct kvm_memory_slot *mslots = slots->memslots;
+	int i;
+
+	for (i = start; i > 0; i--) {
+		if (memslot->base_gfn < mslots[i - 1].base_gfn)
+			break;
+
+		WARN_ON_ONCE(memslot->base_gfn == mslots[i - 1].base_gfn);
+
+		/* Shift the next memslot back one and update its index. */
+		mslots[i] = mslots[i - 1];
+		slots->id_to_index[mslots[i].id] = i;
+	}
+	return i;
+}
+
+/*
+ * Re-sort memslots based on their GFN to account for an added, deleted, or
+ * moved memslot.  Sorting memslots by GFN allows using a binary search during
+ * memslot lookup.
+ *
+ * IMPORTANT: Slots are sorted from highest GFN to lowest GFN!  I.e. the entry
+ * at memslots[0] has the highest GFN.
+ *
+ * The sorting algorithm takes advantage of having initially sorted memslots
+ * and knowing the position of the changed memslot.  Sorting is also optimized
+ * by not swapping the updated memslot and instead only shifting other memslots
+ * and tracking the new index for the update memslot.  Only once its final
+ * index is known is the updated memslot copied into its position in the array.
+ *
+ *  - When deleting a memslot, the deleted memslot simply needs to be moved to
+ *    the end of the array.
+ *
+ *  - When creating a memslot, the algorithm "inserts" the new memslot at the
+ *    end of the array and then it forward to its correct location.
+ *
+ *  - When moving a memslot, the algorithm first moves the updated memslot
+ *    backward to handle the scenario where the memslot's GFN was changed to a
+ *    lower value.  update_memslots() then falls through and runs the same flow
+ *    as creating a memslot to move the memslot forward to handle the scenario
+ *    where its GFN was changed to a higher value.
+ *
+ * Note, slots are sorted from highest->lowest instead of lowest->highest for
+ * historical reasons.  Originally, invalid memslots where denoted by having
+ * GFN=0, thus sorting from highest->lowest naturally sorted invalid memslots
+ * to the end of the array.  The current algorithm uses dedicated logic to
+ * delete a memslot and thus does not rely on invalid memslots having GFN=0.
+ *
+ * The other historical motiviation for highest->lowest was to improve the
+ * performance of memslot lookup.  KVM originally used a linear search starting
+ * at memslots[0].  On x86, the largest memslot usually has one of the highest,
+ * if not *the* highest, GFN, as the bulk of the guest's RAM is located in a
+ * single memslot above the 4gb boundary.  As the largest memslot is also the
+ * most likely to be referenced, sorting it to the front of the array was
+ * advantageous.  The current binary search starts from the middle of the array
+ * and uses an LRU pointer to improve performance for all memslots and GFNs.
+ */
+static void update_memslots(struct kvm_memslots *slots,
+			    struct kvm_memory_slot *memslot,
+			    enum kvm_mr_change change)
+{
+	int i;
+
+	if (change == KVM_MR_DELETE) {
+		kvm_memslot_delete(slots, memslot);
+	} else {
+		if (change == KVM_MR_CREATE)
+			i = kvm_memslot_insert_back(slots);
+		else
+			i = kvm_memslot_move_backward(slots, memslot);
+		i = kvm_memslot_move_forward(slots, memslot, i);
+
+		/*
+		 * Copy the memslot to its new position in memslots and update
+		 * its index accordingly.
+		 */
+		slots->memslots[i] = *memslot;
+		slots->id_to_index[memslot->id] = i;
+	}
+}
+
+static int check_memory_region_flags(const struct kvm_userspace_memory_region *mem)
+{
+	u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES;
+
+#ifdef __KVM_HAVE_READONLY_MEM
+	valid_flags |= KVM_MEM_READONLY;
+#endif
+
+	if (mem->flags & ~valid_flags)
+		return -EINVAL;
+
+	return 0;
+}
+
+static struct kvm_memslots *install_new_memslots(struct kvm *kvm,
+		int as_id, struct kvm_memslots *slots)
+{
+	struct kvm_memslots *old_memslots = __kvm_memslots(kvm, as_id);
+	u64 gen = old_memslots->generation;
+
+	WARN_ON(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS);
+	slots->generation = gen | KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS;
+
+	rcu_assign_pointer(kvm->memslots[as_id], slots);
+	synchronize_srcu_expedited(&kvm->srcu);
+
+	/*
+	 * Increment the new memslot generation a second time, dropping the
+	 * update in-progress flag and incrementing the generation based on
+	 * the number of address spaces.  This provides a unique and easily
+	 * identifiable generation number while the memslots are in flux.
+	 */
+	gen = slots->generation & ~KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS;
+
+	/*
+	 * Generations must be unique even across address spaces.  We do not need
+	 * a global counter for that, instead the generation space is evenly split
+	 * across address spaces.  For example, with two address spaces, address
+	 * space 0 will use generations 0, 2, 4, ... while address space 1 will
+	 * use generations 1, 3, 5, ...
+	 */
+	gen += KVM_ADDRESS_SPACE_NUM;
+
+	kvm_arch_memslots_updated(kvm, gen);
+
+	slots->generation = gen;
+
+	return old_memslots;
+}
+
+/*
+ * Note, at a minimum, the current number of used slots must be allocated, even
+ * when deleting a memslot, as we need a complete duplicate of the memslots for
+ * use when invalidating a memslot prior to deleting/moving the memslot.
+ */
+static struct kvm_memslots *kvm_dup_memslots(struct kvm_memslots *old,
+					     enum kvm_mr_change change)
+{
+	struct kvm_memslots *slots;
+	size_t old_size, new_size;
+
+	old_size = sizeof(struct kvm_memslots) +
+		   (sizeof(struct kvm_memory_slot) * old->used_slots);
+
+	if (change == KVM_MR_CREATE)
+		new_size = old_size + sizeof(struct kvm_memory_slot);
+	else
+		new_size = old_size;
+
+	slots = kvzalloc(new_size, GFP_KERNEL_ACCOUNT);
+	if (likely(slots))
+		memcpy(slots, old, old_size);
+
+	return slots;
+}
+
+static int kvm_set_memslot(struct kvm *kvm,
+			   const struct kvm_userspace_memory_region *mem,
+			   struct kvm_memory_slot *old,
+			   struct kvm_memory_slot *new, int as_id,
+			   enum kvm_mr_change change)
+{
+	struct kvm_memory_slot *slot;
+	struct kvm_memslots *slots;
+	int r;
+
+	slots = kvm_dup_memslots(__kvm_memslots(kvm, as_id), change);
+	if (!slots)
+		return -ENOMEM;
+
+	if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) {
+		/*
+		 * Note, the INVALID flag needs to be in the appropriate entry
+		 * in the freshly allocated memslots, not in @old or @new.
+		 */
+		slot = id_to_memslot(slots, old->id);
+		slot->flags |= KVM_MEMSLOT_INVALID;
+
+		/*
+		 * We can re-use the old memslots, the only difference from the
+		 * newly installed memslots is the invalid flag, which will get
+		 * dropped by update_memslots anyway.  We'll also revert to the
+		 * old memslots if preparing the new memory region fails.
+		 */
+		slots = install_new_memslots(kvm, as_id, slots);
+
+		/* From this point no new shadow pages pointing to a deleted,
+		 * or moved, memslot will be created.
+		 *
+		 * validation of sp->gfn happens in:
+		 *	- gfn_to_hva (kvm_read_guest, gfn_to_pfn)
+		 *	- kvm_is_visible_gfn (mmu_check_root)
+		 */
+		kvm_arch_flush_shadow_memslot(kvm, slot);
+		kvm_arch_guest_memory_reclaimed(kvm);
+	}
+
+	r = kvm_arch_prepare_memory_region(kvm, new, mem, change);
+	if (r)
+		goto out_slots;
+
+	update_memslots(slots, new, change);
+	slots = install_new_memslots(kvm, as_id, slots);
+
+	kvm_arch_commit_memory_region(kvm, mem, old, new, change);
+
+	kvfree(slots);
+	return 0;
+
+out_slots:
+	if (change == KVM_MR_DELETE || change == KVM_MR_MOVE)
+		slots = install_new_memslots(kvm, as_id, slots);
+	kvfree(slots);
+	return r;
+}
+
+static int kvm_delete_memslot(struct kvm *kvm,
+			      const struct kvm_userspace_memory_region *mem,
+			      struct kvm_memory_slot *old, int as_id)
+{
+	struct kvm_memory_slot new;
+	int r;
+
+	if (!old->npages)
+		return -EINVAL;
+
+	memset(&new, 0, sizeof(new));
+	new.id = old->id;
+	/*
+	 * This is only for debugging purpose; it should never be referenced
+	 * for a removed memslot.
+	 */
+	new.as_id = as_id;
+
+	r = kvm_set_memslot(kvm, mem, old, &new, as_id, KVM_MR_DELETE);
+	if (r)
+		return r;
+
+	kvm_free_memslot(kvm, old);
+	return 0;
+}
+
+/*
+ * Allocate some memory and give it an address in the guest physical address
+ * space.
+ *
+ * Discontiguous memory is allowed, mostly for framebuffers.
+ *
+ * Must be called holding kvm->slots_lock for write.
+ */
+int __kvm_set_memory_region(struct kvm *kvm,
+			    const struct kvm_userspace_memory_region *mem)
+{
+	struct kvm_memory_slot old, new;
+	struct kvm_memory_slot *tmp;
+	enum kvm_mr_change change;
+	int as_id, id;
+	int r;
+
+	r = check_memory_region_flags(mem);
+	if (r)
+		return r;
+
+	as_id = mem->slot >> 16;
+	id = (u16)mem->slot;
+
+	/* General sanity checks */
+	if ((mem->memory_size & (PAGE_SIZE - 1)) ||
+	    (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 (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_MEM_SLOTS_NUM)
+		return -EINVAL;
+	if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr)
+		return -EINVAL;
+
+	/*
+	 * Make a full copy of the old memslot, the pointer will become stale
+	 * when the memslots are re-sorted by update_memslots(), and the old
+	 * memslot needs to be referenced after calling update_memslots(), e.g.
+	 * to free its resources and for arch specific behavior.
+	 */
+	tmp = id_to_memslot(__kvm_memslots(kvm, as_id), id);
+	if (tmp) {
+		old = *tmp;
+		tmp = NULL;
+	} else {
+		memset(&old, 0, sizeof(old));
+		old.id = id;
+	}
+
+	if (!mem->memory_size)
+		return kvm_delete_memslot(kvm, mem, &old, as_id);
+
+	new.as_id = as_id;
+	new.id = id;
+	new.base_gfn = mem->guest_phys_addr >> PAGE_SHIFT;
+	new.npages = mem->memory_size >> PAGE_SHIFT;
+	new.flags = mem->flags;
+	new.userspace_addr = mem->userspace_addr;
+
+	if (new.npages > KVM_MEM_MAX_NR_PAGES)
+		return -EINVAL;
+
+	if (!old.npages) {
+		change = KVM_MR_CREATE;
+		new.dirty_bitmap = NULL;
+		memset(&new.arch, 0, sizeof(new.arch));
+	} else { /* Modify an existing slot. */
+		if ((new.userspace_addr != old.userspace_addr) ||
+		    (new.npages != old.npages) ||
+		    ((new.flags ^ old.flags) & KVM_MEM_READONLY))
+			return -EINVAL;
+
+		if (new.base_gfn != old.base_gfn)
+			change = KVM_MR_MOVE;
+		else if (new.flags != old.flags)
+			change = KVM_MR_FLAGS_ONLY;
+		else /* Nothing to change. */
+			return 0;
+
+		/* Copy dirty_bitmap and arch from the current memslot. */
+		new.dirty_bitmap = old.dirty_bitmap;
+		memcpy(&new.arch, &old.arch, sizeof(new.arch));
+	}
+
+	if ((change == KVM_MR_CREATE) || (change == KVM_MR_MOVE)) {
+		/* Check for overlaps */
+		kvm_for_each_memslot(tmp, __kvm_memslots(kvm, as_id)) {
+			if (tmp->id == id)
+				continue;
+			if (!((new.base_gfn + new.npages <= tmp->base_gfn) ||
+			      (new.base_gfn >= tmp->base_gfn + tmp->npages)))
+				return -EEXIST;
+		}
+	}
+
+	/* Allocate/free page dirty bitmap as needed */
+	if (!(new.flags & KVM_MEM_LOG_DIRTY_PAGES))
+		new.dirty_bitmap = NULL;
+	else if (!new.dirty_bitmap) {
+		r = kvm_alloc_dirty_bitmap(&new);
+		if (r)
+			return r;
+
+		if (kvm_dirty_log_manual_protect_and_init_set(kvm))
+			bitmap_set(new.dirty_bitmap, 0, new.npages);
+	}
+
+	r = kvm_set_memslot(kvm, mem, &old, &new, as_id, change);
+	if (r)
+		goto out_bitmap;
+
+	if (old.dirty_bitmap && !new.dirty_bitmap)
+		kvm_destroy_dirty_bitmap(&old);
+	return 0;
+
+out_bitmap:
+	if (new.dirty_bitmap && !old.dirty_bitmap)
+		kvm_destroy_dirty_bitmap(&new);
+	return r;
+}
+EXPORT_SYMBOL_GPL(__kvm_set_memory_region);
+
+int kvm_set_memory_region(struct kvm *kvm,
+			  const struct kvm_userspace_memory_region *mem)
+{
+	int r;
+
+	mutex_lock(&kvm->slots_lock);
+	r = __kvm_set_memory_region(kvm, mem);
+	mutex_unlock(&kvm->slots_lock);
+	return r;
+}
+EXPORT_SYMBOL_GPL(kvm_set_memory_region);
+
+static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
+					  struct kvm_userspace_memory_region *mem)
+{
+	if ((u16)mem->slot >= KVM_USER_MEM_SLOTS)
+		return -EINVAL;
+
+	return kvm_set_memory_region(kvm, mem);
+}
+
+#ifndef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
+/**
+ * kvm_get_dirty_log - get a snapshot of dirty pages
+ * @kvm:	pointer to kvm instance
+ * @log:	slot id and address to which we copy the log
+ * @is_dirty:	set to '1' if any dirty pages were found
+ * @memslot:	set to the associated memslot, always valid on success
+ */
+int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log,
+		      int *is_dirty, struct kvm_memory_slot **memslot)
+{
+	struct kvm_memslots *slots;
+	int i, as_id, id;
+	unsigned long n;
+	unsigned long any = 0;
+
+	*memslot = NULL;
+	*is_dirty = 0;
+
+	as_id = log->slot >> 16;
+	id = (u16)log->slot;
+	if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS)
+		return -EINVAL;
+
+	slots = __kvm_memslots(kvm, as_id);
+	*memslot = id_to_memslot(slots, id);
+	if (!(*memslot) || !(*memslot)->dirty_bitmap)
+		return -ENOENT;
+
+	kvm_arch_sync_dirty_log(kvm, *memslot);
+
+	n = kvm_dirty_bitmap_bytes(*memslot);
+
+	for (i = 0; !any && i < n/sizeof(long); ++i)
+		any = (*memslot)->dirty_bitmap[i];
+
+	if (copy_to_user(log->dirty_bitmap, (*memslot)->dirty_bitmap, n))
+		return -EFAULT;
+
+	if (any)
+		*is_dirty = 1;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_get_dirty_log);
+
+#else /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
+/**
+ * kvm_get_dirty_log_protect - get a snapshot of dirty pages
+ *	and reenable dirty page tracking for the corresponding pages.
+ * @kvm:	pointer to kvm instance
+ * @log:	slot id and address to which we copy the log
+ *
+ * We need to keep it in mind that VCPU threads can write to the bitmap
+ * concurrently. So, to avoid losing track of dirty pages we keep the
+ * following order:
+ *
+ *    1. Take a snapshot of the bit and clear it if needed.
+ *    2. Write protect the corresponding page.
+ *    3. Copy the snapshot to the userspace.
+ *    4. Upon return caller flushes TLB's if needed.
+ *
+ * Between 2 and 4, the guest may write to the page using the remaining TLB
+ * entry.  This is not a problem because the page is reported dirty using
+ * the snapshot taken before and step 4 ensures that writes done after
+ * exiting to userspace will be logged for the next call.
+ *
+ */
+static int kvm_get_dirty_log_protect(struct kvm *kvm, struct kvm_dirty_log *log)
+{
+	struct kvm_memslots *slots;
+	struct kvm_memory_slot *memslot;
+	int i, as_id, id;
+	unsigned long n;
+	unsigned long *dirty_bitmap;
+	unsigned long *dirty_bitmap_buffer;
+	bool flush;
+
+	as_id = log->slot >> 16;
+	id = (u16)log->slot;
+	if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS)
+		return -EINVAL;
+
+	slots = __kvm_memslots(kvm, as_id);
+	memslot = id_to_memslot(slots, id);
+	if (!memslot || !memslot->dirty_bitmap)
+		return -ENOENT;
+
+	dirty_bitmap = memslot->dirty_bitmap;
+
+	kvm_arch_sync_dirty_log(kvm, memslot);
+
+	n = kvm_dirty_bitmap_bytes(memslot);
+	flush = false;
+	if (kvm->manual_dirty_log_protect) {
+		/*
+		 * Unlike kvm_get_dirty_log, we always return false in *flush,
+		 * because no flush is needed until KVM_CLEAR_DIRTY_LOG.  There
+		 * is some code duplication between this function and
+		 * kvm_get_dirty_log, but hopefully all architecture
+		 * transition to kvm_get_dirty_log_protect and kvm_get_dirty_log
+		 * can be eliminated.
+		 */
+		dirty_bitmap_buffer = dirty_bitmap;
+	} else {
+		dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot);
+		memset(dirty_bitmap_buffer, 0, n);
+
+		spin_lock(&kvm->mmu_lock);
+		for (i = 0; i < n / sizeof(long); i++) {
+			unsigned long mask;
+			gfn_t offset;
+
+			if (!dirty_bitmap[i])
+				continue;
+
+			flush = true;
+			mask = xchg(&dirty_bitmap[i], 0);
+			dirty_bitmap_buffer[i] = mask;
+
+			offset = i * BITS_PER_LONG;
+			kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot,
+								offset, mask);
+		}
+		spin_unlock(&kvm->mmu_lock);
+	}
+
+	if (flush)
+		kvm_arch_flush_remote_tlbs_memslot(kvm, memslot);
+
+	if (copy_to_user(log->dirty_bitmap, dirty_bitmap_buffer, n))
+		return -EFAULT;
+	return 0;
+}
+
+
+/**
+ * kvm_vm_ioctl_get_dirty_log - get and clear the log of dirty pages in a slot
+ * @kvm: kvm instance
+ * @log: slot id and address to which we copy the log
+ *
+ * Steps 1-4 below provide general overview of dirty page logging. See
+ * kvm_get_dirty_log_protect() function description for additional details.
+ *
+ * We call kvm_get_dirty_log_protect() to handle steps 1-3, upon return we
+ * always flush the TLB (step 4) even if previous step failed  and the dirty
+ * bitmap may be corrupt. Regardless of previous outcome the KVM logging API
+ * does not preclude user space subsequent dirty log read. Flushing TLB ensures
+ * writes will be marked dirty for next log read.
+ *
+ *   1. Take a snapshot of the bit and clear it if needed.
+ *   2. Write protect the corresponding page.
+ *   3. Copy the snapshot to the userspace.
+ *   4. Flush TLB's if needed.
+ */
+static int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
+				      struct kvm_dirty_log *log)
+{
+	int r;
+
+	mutex_lock(&kvm->slots_lock);
+
+	r = kvm_get_dirty_log_protect(kvm, log);
+
+	mutex_unlock(&kvm->slots_lock);
+	return r;
+}
+
+/**
+ * kvm_clear_dirty_log_protect - clear dirty bits in the bitmap
+ *	and reenable dirty page tracking for the corresponding pages.
+ * @kvm:	pointer to kvm instance
+ * @log:	slot id and address from which to fetch the bitmap of dirty pages
+ */
+static int kvm_clear_dirty_log_protect(struct kvm *kvm,
+				       struct kvm_clear_dirty_log *log)
+{
+	struct kvm_memslots *slots;
+	struct kvm_memory_slot *memslot;
+	int as_id, id;
+	gfn_t offset;
+	unsigned long i, n;
+	unsigned long *dirty_bitmap;
+	unsigned long *dirty_bitmap_buffer;
+	bool flush;
+
+	as_id = log->slot >> 16;
+	id = (u16)log->slot;
+	if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS)
+		return -EINVAL;
+
+	if (log->first_page & 63)
+		return -EINVAL;
+
+	slots = __kvm_memslots(kvm, as_id);
+	memslot = id_to_memslot(slots, id);
+	if (!memslot || !memslot->dirty_bitmap)
+		return -ENOENT;
+
+	dirty_bitmap = memslot->dirty_bitmap;
+
+	n = ALIGN(log->num_pages, BITS_PER_LONG) / 8;
+
+	if (log->first_page > memslot->npages ||
+	    log->num_pages > memslot->npages - log->first_page ||
+	    (log->num_pages < memslot->npages - log->first_page && (log->num_pages & 63)))
+	    return -EINVAL;
+
+	kvm_arch_sync_dirty_log(kvm, memslot);
+
+	flush = false;
+	dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot);
+	if (copy_from_user(dirty_bitmap_buffer, log->dirty_bitmap, n))
+		return -EFAULT;
+
+	spin_lock(&kvm->mmu_lock);
+	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);
+		}
+	}
+	spin_unlock(&kvm->mmu_lock);
+
+	if (flush)
+		kvm_arch_flush_remote_tlbs_memslot(kvm, memslot);
+
+	return 0;
+}
+
+static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
+					struct kvm_clear_dirty_log *log)
+{
+	int r;
+
+	mutex_lock(&kvm->slots_lock);
+
+	r = kvm_clear_dirty_log_protect(kvm, log);
+
+	mutex_unlock(&kvm->slots_lock);
+	return r;
+}
+#endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
+
+struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
+{
+	return __gfn_to_memslot(kvm_memslots(kvm), gfn);
+}
+EXPORT_SYMBOL_GPL(gfn_to_memslot);
+
+struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn)
+{
+	return __gfn_to_memslot(kvm_vcpu_memslots(vcpu), gfn);
+}
+
+bool kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
+{
+	struct kvm_memory_slot *memslot = gfn_to_memslot(kvm, gfn);
+
+	return kvm_is_visible_memslot(memslot);
+}
+EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);
+
+bool kvm_vcpu_is_visible_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
+{
+	struct kvm_memory_slot *memslot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
+
+	return kvm_is_visible_memslot(memslot);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_is_visible_gfn);
+
+unsigned long kvm_host_page_size(struct kvm_vcpu *vcpu, gfn_t gfn)
+{
+	struct vm_area_struct *vma;
+	unsigned long addr, size;
+
+	size = PAGE_SIZE;
+
+	addr = kvm_vcpu_gfn_to_hva_prot(vcpu, gfn, NULL);
+	if (kvm_is_error_hva(addr))
+		return PAGE_SIZE;
+
+	mmap_read_lock(current->mm);
+	vma = find_vma(current->mm, addr);
+	if (!vma)
+		goto out;
+
+	size = vma_kernel_pagesize(vma);
+
+out:
+	mmap_read_unlock(current->mm);
+
+	return size;
+}
+
+static bool memslot_is_readonly(struct kvm_memory_slot *slot)
+{
+	return slot->flags & KVM_MEM_READONLY;
+}
+
+static unsigned long __gfn_to_hva_many(struct kvm_memory_slot *slot, gfn_t gfn,
+				       gfn_t *nr_pages, bool write)
+{
+	if (!slot || slot->flags & KVM_MEMSLOT_INVALID)
+		return KVM_HVA_ERR_BAD;
+
+	if (memslot_is_readonly(slot) && write)
+		return KVM_HVA_ERR_RO_BAD;
+
+	if (nr_pages)
+		*nr_pages = slot->npages - (gfn - slot->base_gfn);
+
+	return __gfn_to_hva_memslot(slot, gfn);
+}
+
+static unsigned long gfn_to_hva_many(struct kvm_memory_slot *slot, gfn_t gfn,
+				     gfn_t *nr_pages)
+{
+	return __gfn_to_hva_many(slot, gfn, nr_pages, true);
+}
+
+unsigned long gfn_to_hva_memslot(struct kvm_memory_slot *slot,
+					gfn_t gfn)
+{
+	return gfn_to_hva_many(slot, gfn, NULL);
+}
+EXPORT_SYMBOL_GPL(gfn_to_hva_memslot);
+
+unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
+{
+	return gfn_to_hva_many(gfn_to_memslot(kvm, gfn), gfn, NULL);
+}
+EXPORT_SYMBOL_GPL(gfn_to_hva);
+
+unsigned long kvm_vcpu_gfn_to_hva(struct kvm_vcpu *vcpu, gfn_t gfn)
+{
+	return gfn_to_hva_many(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn, NULL);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_hva);
+
+/*
+ * Return the hva of a @gfn and the R/W attribute if possible.
+ *
+ * @slot: the kvm_memory_slot which contains @gfn
+ * @gfn: the gfn to be translated
+ * @writable: used to return the read/write attribute of the @slot if the hva
+ * is valid and @writable is not NULL
+ */
+unsigned long gfn_to_hva_memslot_prot(struct kvm_memory_slot *slot,
+				      gfn_t gfn, bool *writable)
+{
+	unsigned long hva = __gfn_to_hva_many(slot, gfn, NULL, false);
+
+	if (!kvm_is_error_hva(hva) && writable)
+		*writable = !memslot_is_readonly(slot);
+
+	return hva;
+}
+
+unsigned long gfn_to_hva_prot(struct kvm *kvm, gfn_t gfn, bool *writable)
+{
+	struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
+
+	return gfn_to_hva_memslot_prot(slot, gfn, writable);
+}
+
+unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *writable)
+{
+	struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
+
+	return gfn_to_hva_memslot_prot(slot, gfn, writable);
+}
+
+static inline int check_user_page_hwpoison(unsigned long addr)
+{
+	int rc, flags = FOLL_HWPOISON | FOLL_WRITE;
+
+	rc = get_user_pages(addr, 1, flags, NULL, NULL);
+	return rc == -EHWPOISON;
+}
+
+/*
+ * The fast path to get the writable pfn which will be stored in @pfn,
+ * true indicates success, otherwise false is returned.  It's also the
+ * only part that runs if we can in atomic context.
+ */
+static bool hva_to_pfn_fast(unsigned long addr, bool write_fault,
+			    bool *writable, kvm_pfn_t *pfn)
+{
+	struct page *page[1];
+
+	/*
+	 * Fast pin a writable pfn only if it is a write fault request
+	 * or the caller allows to map a writable pfn for a read fault
+	 * request.
+	 */
+	if (!(write_fault || writable))
+		return false;
+
+	if (get_user_page_fast_only(addr, FOLL_WRITE, page)) {
+		*pfn = page_to_pfn(page[0]);
+
+		if (writable)
+			*writable = true;
+		return true;
+	}
+
+	return false;
+}
+
+/*
+ * The slow path to get the pfn of the specified host virtual address,
+ * 1 indicates success, -errno is returned if error is detected.
+ */
+static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault,
+			   bool *writable, kvm_pfn_t *pfn)
+{
+	unsigned int flags = FOLL_HWPOISON;
+	struct page *page;
+	int npages = 0;
+
+	might_sleep();
+
+	if (writable)
+		*writable = write_fault;
+
+	if (write_fault)
+		flags |= FOLL_WRITE;
+	if (async)
+		flags |= FOLL_NOWAIT;
+
+	npages = get_user_pages_unlocked(addr, 1, &page, flags);
+	if (npages != 1)
+		return npages;
+
+	/* map read fault as writable if possible */
+	if (unlikely(!write_fault) && writable) {
+		struct page *wpage;
+
+		if (get_user_page_fast_only(addr, FOLL_WRITE, &wpage)) {
+			*writable = true;
+			put_page(page);
+			page = wpage;
+		}
+	}
+	*pfn = page_to_pfn(page);
+	return npages;
+}
+
+static bool vma_is_valid(struct vm_area_struct *vma, bool write_fault)
+{
+	if (unlikely(!(vma->vm_flags & VM_READ)))
+		return false;
+
+	if (write_fault && (unlikely(!(vma->vm_flags & VM_WRITE))))
+		return false;
+
+	return true;
+}
+
+static int kvm_try_get_pfn(kvm_pfn_t pfn)
+{
+	if (kvm_is_reserved_pfn(pfn))
+		return 1;
+	return get_page_unless_zero(pfn_to_page(pfn));
+}
+
+static int hva_to_pfn_remapped(struct vm_area_struct *vma,
+			       unsigned long addr, bool *async,
+			       bool write_fault, bool *writable,
+			       kvm_pfn_t *p_pfn)
+{
+	kvm_pfn_t pfn;
+	pte_t *ptep;
+	spinlock_t *ptl;
+	int r;
+
+	r = follow_pte(vma->vm_mm, addr, &ptep, &ptl);
+	if (r) {
+		/*
+		 * get_user_pages fails for VM_IO and VM_PFNMAP vmas and does
+		 * not call the fault handler, so do it here.
+		 */
+		bool unlocked = false;
+		r = fixup_user_fault(current->mm, addr,
+				     (write_fault ? FAULT_FLAG_WRITE : 0),
+				     &unlocked);
+		if (unlocked)
+			return -EAGAIN;
+		if (r)
+			return r;
+
+		r = follow_pte(vma->vm_mm, addr, &ptep, &ptl);
+		if (r)
+			return r;
+	}
+
+	if (write_fault && !pte_write(*ptep)) {
+		pfn = KVM_PFN_ERR_RO_FAULT;
+		goto out;
+	}
+
+	if (writable)
+		*writable = pte_write(*ptep);
+	pfn = pte_pfn(*ptep);
+
+	/*
+	 * Get a reference here because callers of *hva_to_pfn* and
+	 * *gfn_to_pfn* ultimately call kvm_release_pfn_clean on the
+	 * returned pfn.  This is only needed if the VMA has VM_MIXEDMAP
+	 * set, but the kvm_get_pfn/kvm_release_pfn_clean pair will
+	 * simply do nothing for reserved pfns.
+	 *
+	 * Whoever called remap_pfn_range is also going to call e.g.
+	 * unmap_mapping_range before the underlying pages are freed,
+	 * causing a call to our MMU notifier.
+	 *
+	 * Certain IO or PFNMAP mappings can be backed with valid
+	 * struct pages, but be allocated without refcounting e.g.,
+	 * tail pages of non-compound higher order allocations, which
+	 * would then underflow the refcount when the caller does the
+	 * required put_page. Don't allow those pages here.
+	 */ 
+	if (!kvm_try_get_pfn(pfn))
+		r = -EFAULT;
+
+out:
+	pte_unmap_unlock(ptep, ptl);
+	*p_pfn = pfn;
+
+	return r;
+}
+
+/*
+ * Pin guest page in memory and return its pfn.
+ * @addr: host virtual address which maps memory to the guest
+ * @atomic: whether this function can sleep
+ * @async: whether this function need to wait IO complete if the
+ *         host page is not in the memory
+ * @write_fault: whether we should get a writable host page
+ * @writable: whether it allows to map a writable host page for !@write_fault
+ *
+ * The function will map a writable host page for these two cases:
+ * 1): @write_fault = true
+ * 2): @write_fault = false && @writable, @writable will tell the caller
+ *     whether the mapping is writable.
+ */
+static kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
+			bool write_fault, bool *writable)
+{
+	struct vm_area_struct *vma;
+	kvm_pfn_t pfn = 0;
+	int npages, r;
+
+	/* we can do it either atomically or asynchronously, not both */
+	BUG_ON(atomic && async);
+
+	if (hva_to_pfn_fast(addr, write_fault, writable, &pfn))
+		return pfn;
+
+	if (atomic)
+		return KVM_PFN_ERR_FAULT;
+
+	npages = hva_to_pfn_slow(addr, async, write_fault, writable, &pfn);
+	if (npages == 1)
+		return pfn;
+
+	mmap_read_lock(current->mm);
+	if (npages == -EHWPOISON ||
+	      (!async && check_user_page_hwpoison(addr))) {
+		pfn = KVM_PFN_ERR_HWPOISON;
+		goto exit;
+	}
+
+retry:
+	vma = find_vma_intersection(current->mm, addr, addr + 1);
+
+	if (vma == NULL)
+		pfn = KVM_PFN_ERR_FAULT;
+	else if (vma->vm_flags & (VM_IO | VM_PFNMAP)) {
+		r = hva_to_pfn_remapped(vma, addr, async, write_fault, writable, &pfn);
+		if (r == -EAGAIN)
+			goto retry;
+		if (r < 0)
+			pfn = KVM_PFN_ERR_FAULT;
+	} else {
+		if (async && vma_is_valid(vma, write_fault))
+			*async = true;
+		pfn = KVM_PFN_ERR_FAULT;
+	}
+exit:
+	mmap_read_unlock(current->mm);
+	return pfn;
+}
+
+kvm_pfn_t __gfn_to_pfn_memslot(struct kvm_memory_slot *slot, gfn_t gfn,
+			       bool atomic, bool *async, bool write_fault,
+			       bool *writable)
+{
+	unsigned long addr = __gfn_to_hva_many(slot, gfn, NULL, write_fault);
+
+	if (addr == KVM_HVA_ERR_RO_BAD) {
+		if (writable)
+			*writable = false;
+		return KVM_PFN_ERR_RO_FAULT;
+	}
+
+	if (kvm_is_error_hva(addr)) {
+		if (writable)
+			*writable = false;
+		return KVM_PFN_NOSLOT;
+	}
+
+	/* Do not map writable pfn in the readonly memslot. */
+	if (writable && memslot_is_readonly(slot)) {
+		*writable = false;
+		writable = NULL;
+	}
+
+	return hva_to_pfn(addr, atomic, async, write_fault,
+			  writable);
+}
+EXPORT_SYMBOL_GPL(__gfn_to_pfn_memslot);
+
+kvm_pfn_t gfn_to_pfn_prot(struct kvm *kvm, gfn_t gfn, bool write_fault,
+		      bool *writable)
+{
+	return __gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn, false, NULL,
+				    write_fault, writable);
+}
+EXPORT_SYMBOL_GPL(gfn_to_pfn_prot);
+
+kvm_pfn_t gfn_to_pfn_memslot(struct kvm_memory_slot *slot, gfn_t gfn)
+{
+	return __gfn_to_pfn_memslot(slot, gfn, false, NULL, true, NULL);
+}
+EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot);
+
+kvm_pfn_t gfn_to_pfn_memslot_atomic(struct kvm_memory_slot *slot, gfn_t gfn)
+{
+	return __gfn_to_pfn_memslot(slot, gfn, true, NULL, true, NULL);
+}
+EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot_atomic);
+
+kvm_pfn_t kvm_vcpu_gfn_to_pfn_atomic(struct kvm_vcpu *vcpu, gfn_t gfn)
+{
+	return gfn_to_pfn_memslot_atomic(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_pfn_atomic);
+
+kvm_pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
+{
+	return gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn);
+}
+EXPORT_SYMBOL_GPL(gfn_to_pfn);
+
+kvm_pfn_t kvm_vcpu_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn)
+{
+	return gfn_to_pfn_memslot(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_pfn);
+
+int gfn_to_page_many_atomic(struct kvm_memory_slot *slot, gfn_t gfn,
+			    struct page **pages, int nr_pages)
+{
+	unsigned long addr;
+	gfn_t entry = 0;
+
+	addr = gfn_to_hva_many(slot, gfn, &entry);
+	if (kvm_is_error_hva(addr))
+		return -1;
+
+	if (entry < nr_pages)
+		return 0;
+
+	return get_user_pages_fast_only(addr, nr_pages, FOLL_WRITE, pages);
+}
+EXPORT_SYMBOL_GPL(gfn_to_page_many_atomic);
+
+static struct page *kvm_pfn_to_page(kvm_pfn_t pfn)
+{
+	if (is_error_noslot_pfn(pfn))
+		return KVM_ERR_PTR_BAD_PAGE;
+
+	if (kvm_is_reserved_pfn(pfn)) {
+		WARN_ON(1);
+		return KVM_ERR_PTR_BAD_PAGE;
+	}
+
+	return pfn_to_page(pfn);
+}
+
+struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
+{
+	kvm_pfn_t pfn;
+
+	pfn = gfn_to_pfn(kvm, gfn);
+
+	return kvm_pfn_to_page(pfn);
+}
+EXPORT_SYMBOL_GPL(gfn_to_page);
+
+void kvm_release_pfn(kvm_pfn_t pfn, bool dirty, struct gfn_to_pfn_cache *cache)
+{
+	if (pfn == 0)
+		return;
+
+	if (cache)
+		cache->pfn = cache->gfn = 0;
+
+	if (dirty)
+		kvm_release_pfn_dirty(pfn);
+	else
+		kvm_release_pfn_clean(pfn);
+}
+
+static void kvm_cache_gfn_to_pfn(struct kvm_memory_slot *slot, gfn_t gfn,
+				 struct gfn_to_pfn_cache *cache, u64 gen)
+{
+	kvm_release_pfn(cache->pfn, cache->dirty, cache);
+
+	cache->pfn = gfn_to_pfn_memslot(slot, gfn);
+	cache->gfn = gfn;
+	cache->dirty = false;
+	cache->generation = gen;
+}
+
+static int __kvm_map_gfn(struct kvm_memslots *slots, gfn_t gfn,
+			 struct kvm_host_map *map,
+			 struct gfn_to_pfn_cache *cache,
+			 bool atomic)
+{
+	kvm_pfn_t pfn;
+	void *hva = NULL;
+	struct page *page = KVM_UNMAPPED_PAGE;
+	struct kvm_memory_slot *slot = __gfn_to_memslot(slots, gfn);
+	u64 gen = slots->generation;
+
+	if (!map)
+		return -EINVAL;
+
+	if (cache) {
+		if (!cache->pfn || cache->gfn != gfn ||
+			cache->generation != gen) {
+			if (atomic)
+				return -EAGAIN;
+			kvm_cache_gfn_to_pfn(slot, gfn, cache, gen);
+		}
+		pfn = cache->pfn;
+	} else {
+		if (atomic)
+			return -EAGAIN;
+		pfn = gfn_to_pfn_memslot(slot, gfn);
+	}
+	if (is_error_noslot_pfn(pfn))
+		return -EINVAL;
+
+	if (pfn_valid(pfn)) {
+		page = pfn_to_page(pfn);
+		if (atomic)
+			hva = kmap_atomic(page);
+		else
+			hva = kmap(page);
+#ifdef CONFIG_HAS_IOMEM
+	} else if (!atomic) {
+		hva = memremap(pfn_to_hpa(pfn), PAGE_SIZE, MEMREMAP_WB);
+	} else {
+		return -EINVAL;
+#endif
+	}
+
+	if (!hva)
+		return -EFAULT;
+
+	map->page = page;
+	map->hva = hva;
+	map->pfn = pfn;
+	map->gfn = gfn;
+
+	return 0;
+}
+
+int kvm_map_gfn(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map,
+		struct gfn_to_pfn_cache *cache, bool atomic)
+{
+	return __kvm_map_gfn(kvm_memslots(vcpu->kvm), gfn, map,
+			cache, atomic);
+}
+EXPORT_SYMBOL_GPL(kvm_map_gfn);
+
+int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map)
+{
+	return __kvm_map_gfn(kvm_vcpu_memslots(vcpu), gfn, map,
+		NULL, false);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_map);
+
+static void __kvm_unmap_gfn(struct kvm_memory_slot *memslot,
+			struct kvm_host_map *map,
+			struct gfn_to_pfn_cache *cache,
+			bool dirty, bool atomic)
+{
+	if (!map)
+		return;
+
+	if (!map->hva)
+		return;
+
+	if (map->page != KVM_UNMAPPED_PAGE) {
+		if (atomic)
+			kunmap_atomic(map->hva);
+		else
+			kunmap(map->page);
+	}
+#ifdef CONFIG_HAS_IOMEM
+	else if (!atomic)
+		memunmap(map->hva);
+	else
+		WARN_ONCE(1, "Unexpected unmapping in atomic context");
+#endif
+
+	if (dirty)
+		mark_page_dirty_in_slot(memslot, map->gfn);
+
+	if (cache)
+		cache->dirty |= dirty;
+	else
+		kvm_release_pfn(map->pfn, dirty, NULL);
+
+	map->hva = NULL;
+	map->page = NULL;
+}
+
+int kvm_unmap_gfn(struct kvm_vcpu *vcpu, struct kvm_host_map *map, 
+		  struct gfn_to_pfn_cache *cache, bool dirty, bool atomic)
+{
+	__kvm_unmap_gfn(gfn_to_memslot(vcpu->kvm, map->gfn), map,
+			cache, dirty, atomic);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_unmap_gfn);
+
+void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map, bool dirty)
+{
+	__kvm_unmap_gfn(kvm_vcpu_gfn_to_memslot(vcpu, map->gfn), map, NULL,
+			dirty, false);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_unmap);
+
+struct page *kvm_vcpu_gfn_to_page(struct kvm_vcpu *vcpu, gfn_t gfn)
+{
+	kvm_pfn_t pfn;
+
+	pfn = kvm_vcpu_gfn_to_pfn(vcpu, gfn);
+
+	return kvm_pfn_to_page(pfn);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_page);
+
+void kvm_release_page_clean(struct page *page)
+{
+	WARN_ON(is_error_page(page));
+
+	kvm_release_pfn_clean(page_to_pfn(page));
+}
+EXPORT_SYMBOL_GPL(kvm_release_page_clean);
+
+void kvm_release_pfn_clean(kvm_pfn_t pfn)
+{
+	if (!is_error_noslot_pfn(pfn) && !kvm_is_reserved_pfn(pfn))
+		put_page(pfn_to_page(pfn));
+}
+EXPORT_SYMBOL_GPL(kvm_release_pfn_clean);
+
+void kvm_release_page_dirty(struct page *page)
+{
+	WARN_ON(is_error_page(page));
+
+	kvm_release_pfn_dirty(page_to_pfn(page));
+}
+EXPORT_SYMBOL_GPL(kvm_release_page_dirty);
+
+void kvm_release_pfn_dirty(kvm_pfn_t pfn)
+{
+	kvm_set_pfn_dirty(pfn);
+	kvm_release_pfn_clean(pfn);
+}
+EXPORT_SYMBOL_GPL(kvm_release_pfn_dirty);
+
+static bool kvm_is_ad_tracked_pfn(kvm_pfn_t pfn)
+{
+	if (!pfn_valid(pfn))
+		return false;
+
+	/*
+	 * Per page-flags.h, pages tagged PG_reserved "should in general not be
+	 * touched (e.g. set dirty) except by its owner".
+	 */
+	return !PageReserved(pfn_to_page(pfn));
+}
+
+void kvm_set_pfn_dirty(kvm_pfn_t pfn)
+{
+	if (kvm_is_ad_tracked_pfn(pfn))
+		SetPageDirty(pfn_to_page(pfn));
+}
+EXPORT_SYMBOL_GPL(kvm_set_pfn_dirty);
+
+void kvm_set_pfn_accessed(kvm_pfn_t pfn)
+{
+	if (kvm_is_ad_tracked_pfn(pfn))
+		mark_page_accessed(pfn_to_page(pfn));
+}
+EXPORT_SYMBOL_GPL(kvm_set_pfn_accessed);
+
+void kvm_get_pfn(kvm_pfn_t pfn)
+{
+	if (!kvm_is_reserved_pfn(pfn))
+		get_page(pfn_to_page(pfn));
+}
+EXPORT_SYMBOL_GPL(kvm_get_pfn);
+
+static int next_segment(unsigned long len, int offset)
+{
+	if (len > PAGE_SIZE - offset)
+		return PAGE_SIZE - offset;
+	else
+		return len;
+}
+
+static int __kvm_read_guest_page(struct kvm_memory_slot *slot, gfn_t gfn,
+				 void *data, int offset, int len)
+{
+	int r;
+	unsigned long addr;
+
+	addr = gfn_to_hva_memslot_prot(slot, gfn, NULL);
+	if (kvm_is_error_hva(addr))
+		return -EFAULT;
+	r = __copy_from_user(data, (void __user *)addr + offset, len);
+	if (r)
+		return -EFAULT;
+	return 0;
+}
+
+int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
+			int len)
+{
+	struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
+
+	return __kvm_read_guest_page(slot, gfn, data, offset, len);
+}
+EXPORT_SYMBOL_GPL(kvm_read_guest_page);
+
+int kvm_vcpu_read_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, void *data,
+			     int offset, int len)
+{
+	struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
+
+	return __kvm_read_guest_page(slot, gfn, data, offset, len);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_page);
+
+int kvm_read_guest(struct kvm *kvm, gpa_t gpa, void *data, unsigned long len)
+{
+	gfn_t gfn = gpa >> PAGE_SHIFT;
+	int seg;
+	int offset = offset_in_page(gpa);
+	int ret;
+
+	while ((seg = next_segment(len, offset)) != 0) {
+		ret = kvm_read_guest_page(kvm, gfn, data, offset, seg);
+		if (ret < 0)
+			return ret;
+		offset = 0;
+		len -= seg;
+		data += seg;
+		++gfn;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_read_guest);
+
+int kvm_vcpu_read_guest(struct kvm_vcpu *vcpu, gpa_t gpa, void *data, unsigned long len)
+{
+	gfn_t gfn = gpa >> PAGE_SHIFT;
+	int seg;
+	int offset = offset_in_page(gpa);
+	int ret;
+
+	while ((seg = next_segment(len, offset)) != 0) {
+		ret = kvm_vcpu_read_guest_page(vcpu, gfn, data, offset, seg);
+		if (ret < 0)
+			return ret;
+		offset = 0;
+		len -= seg;
+		data += seg;
+		++gfn;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest);
+
+static int __kvm_read_guest_atomic(struct kvm_memory_slot *slot, gfn_t gfn,
+			           void *data, int offset, unsigned long len)
+{
+	int r;
+	unsigned long addr;
+
+	addr = gfn_to_hva_memslot_prot(slot, gfn, NULL);
+	if (kvm_is_error_hva(addr))
+		return -EFAULT;
+	pagefault_disable();
+	r = __copy_from_user_inatomic(data, (void __user *)addr + offset, len);
+	pagefault_enable();
+	if (r)
+		return -EFAULT;
+	return 0;
+}
+
+int kvm_vcpu_read_guest_atomic(struct kvm_vcpu *vcpu, gpa_t gpa,
+			       void *data, unsigned long len)
+{
+	gfn_t gfn = gpa >> PAGE_SHIFT;
+	struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
+	int offset = offset_in_page(gpa);
+
+	return __kvm_read_guest_atomic(slot, gfn, data, offset, len);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_atomic);
+
+static int __kvm_write_guest_page(struct kvm_memory_slot *memslot, gfn_t gfn,
+			          const void *data, int offset, int len)
+{
+	int r;
+	unsigned long addr;
+
+	addr = gfn_to_hva_memslot(memslot, gfn);
+	if (kvm_is_error_hva(addr))
+		return -EFAULT;
+	r = __copy_to_user((void __user *)addr + offset, data, len);
+	if (r)
+		return -EFAULT;
+	mark_page_dirty_in_slot(memslot, gfn);
+	return 0;
+}
+
+int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn,
+			 const void *data, int offset, int len)
+{
+	struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
+
+	return __kvm_write_guest_page(slot, gfn, data, offset, len);
+}
+EXPORT_SYMBOL_GPL(kvm_write_guest_page);
+
+int kvm_vcpu_write_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn,
+			      const void *data, int offset, int len)
+{
+	struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
+
+	return __kvm_write_guest_page(slot, gfn, data, offset, len);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_write_guest_page);
+
+int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data,
+		    unsigned long len)
+{
+	gfn_t gfn = gpa >> PAGE_SHIFT;
+	int seg;
+	int offset = offset_in_page(gpa);
+	int ret;
+
+	while ((seg = next_segment(len, offset)) != 0) {
+		ret = kvm_write_guest_page(kvm, gfn, data, offset, seg);
+		if (ret < 0)
+			return ret;
+		offset = 0;
+		len -= seg;
+		data += seg;
+		++gfn;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_write_guest);
+
+int kvm_vcpu_write_guest(struct kvm_vcpu *vcpu, gpa_t gpa, const void *data,
+		         unsigned long len)
+{
+	gfn_t gfn = gpa >> PAGE_SHIFT;
+	int seg;
+	int offset = offset_in_page(gpa);
+	int ret;
+
+	while ((seg = next_segment(len, offset)) != 0) {
+		ret = kvm_vcpu_write_guest_page(vcpu, gfn, data, offset, seg);
+		if (ret < 0)
+			return ret;
+		offset = 0;
+		len -= seg;
+		data += seg;
+		++gfn;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_write_guest);
+
+static int __kvm_gfn_to_hva_cache_init(struct kvm_memslots *slots,
+				       struct gfn_to_hva_cache *ghc,
+				       gpa_t gpa, unsigned long len)
+{
+	int offset = offset_in_page(gpa);
+	gfn_t start_gfn = gpa >> PAGE_SHIFT;
+	gfn_t end_gfn = (gpa + len - 1) >> PAGE_SHIFT;
+	gfn_t nr_pages_needed = end_gfn - start_gfn + 1;
+	gfn_t nr_pages_avail;
+
+	/* 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(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_page(struct kvm *kvm, gfn_t gfn, int offset, int len)
+{
+	const void *zero_page = (const void *) __va(page_to_phys(ZERO_PAGE(0)));
+
+	return kvm_write_guest_page(kvm, gfn, zero_page, offset, len);
+}
+EXPORT_SYMBOL_GPL(kvm_clear_guest_page);
+
+int kvm_clear_guest(struct kvm *kvm, gpa_t gpa, unsigned long len)
+{
+	gfn_t gfn = gpa >> PAGE_SHIFT;
+	int seg;
+	int offset = offset_in_page(gpa);
+	int ret;
+
+	while ((seg = next_segment(len, offset)) != 0) {
+		ret = kvm_clear_guest_page(kvm, gfn, offset, seg);
+		if (ret < 0)
+			return ret;
+		offset = 0;
+		len -= seg;
+		++gfn;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_clear_guest);
+
+void mark_page_dirty_in_slot(struct kvm_memory_slot *memslot, gfn_t gfn)
+{
+	if (memslot && memslot->dirty_bitmap) {
+		unsigned long rel_gfn = gfn - memslot->base_gfn;
+
+		set_bit_le(rel_gfn, memslot->dirty_bitmap);
+	}
+}
+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(memslot, gfn);
+}
+EXPORT_SYMBOL_GPL(mark_page_dirty);
+
+void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn)
+{
+	struct kvm_memory_slot *memslot;
+
+	memslot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
+	mark_page_dirty_in_slot(memslot, gfn);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_mark_page_dirty);
+
+void kvm_sigset_activate(struct kvm_vcpu *vcpu)
+{
+	if (!vcpu->sigset_active)
+		return;
+
+	/*
+	 * This does a lockless modification of ->real_blocked, which is fine
+	 * because, only current can change ->real_blocked and all readers of
+	 * ->real_blocked don't care as long ->real_blocked is always a subset
+	 * of ->blocked.
+	 */
+	sigprocmask(SIG_SETMASK, &vcpu->sigset, &current->real_blocked);
+}
+
+void kvm_sigset_deactivate(struct kvm_vcpu *vcpu)
+{
+	if (!vcpu->sigset_active)
+		return;
+
+	sigprocmask(SIG_SETMASK, &current->real_blocked, NULL);
+	sigemptyset(&current->real_blocked);
+}
+
+static void grow_halt_poll_ns(struct kvm_vcpu *vcpu)
+{
+	unsigned int old, val, grow, grow_start;
+
+	old = val = vcpu->halt_poll_ns;
+	grow_start = READ_ONCE(halt_poll_ns_grow_start);
+	grow = READ_ONCE(halt_poll_ns_grow);
+	if (!grow)
+		goto out;
+
+	val *= grow;
+	if (val < grow_start)
+		val = grow_start;
+
+	if (val > vcpu->kvm->max_halt_poll_ns)
+		val = vcpu->kvm->max_halt_poll_ns;
+
+	vcpu->halt_poll_ns = val;
+out:
+	trace_kvm_halt_poll_ns_grow(vcpu->vcpu_id, val, old);
+}
+
+static void shrink_halt_poll_ns(struct kvm_vcpu *vcpu)
+{
+	unsigned int old, val, shrink, grow_start;
+
+	old = val = vcpu->halt_poll_ns;
+	shrink = READ_ONCE(halt_poll_ns_shrink);
+	grow_start = READ_ONCE(halt_poll_ns_grow_start);
+	if (shrink == 0)
+		val = 0;
+	else
+		val /= shrink;
+
+	if (val < grow_start)
+		val = 0;
+
+	vcpu->halt_poll_ns = val;
+	trace_kvm_halt_poll_ns_shrink(vcpu->vcpu_id, val, old);
+}
+
+static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu)
+{
+	int ret = -EINTR;
+	int idx = srcu_read_lock(&vcpu->kvm->srcu);
+
+	if (kvm_arch_vcpu_runnable(vcpu)) {
+		kvm_make_request(KVM_REQ_UNHALT, vcpu);
+		goto out;
+	}
+	if (kvm_cpu_has_pending_timer(vcpu))
+		goto out;
+	if (signal_pending(current))
+		goto out;
+
+	ret = 0;
+out:
+	srcu_read_unlock(&vcpu->kvm->srcu, idx);
+	return ret;
+}
+
+static inline void
+update_halt_poll_stats(struct kvm_vcpu *vcpu, u64 poll_ns, bool waited)
+{
+	if (waited)
+		vcpu->stat.halt_poll_fail_ns += poll_ns;
+	else
+		vcpu->stat.halt_poll_success_ns += poll_ns;
+}
+
+/*
+ * The vCPU has executed a HLT instruction with in-kernel mode enabled.
+ */
+void kvm_vcpu_block(struct kvm_vcpu *vcpu)
+{
+	ktime_t start, cur, poll_end;
+	bool waited = false;
+	u64 block_ns;
+
+	kvm_arch_vcpu_blocking(vcpu);
+
+	start = cur = poll_end = ktime_get();
+	if (vcpu->halt_poll_ns && !kvm_arch_no_poll(vcpu)) {
+		ktime_t stop = ktime_add_ns(ktime_get(), vcpu->halt_poll_ns);
+
+		++vcpu->stat.halt_attempted_poll;
+		do {
+			/*
+			 * This sets KVM_REQ_UNHALT if an interrupt
+			 * arrives.
+			 */
+			if (kvm_vcpu_check_block(vcpu) < 0) {
+				++vcpu->stat.halt_successful_poll;
+				if (!vcpu_valid_wakeup(vcpu))
+					++vcpu->stat.halt_poll_invalid;
+				goto out;
+			}
+			poll_end = cur = ktime_get();
+		} while (single_task_running() && !need_resched() &&
+			 ktime_before(cur, stop));
+	}
+
+	prepare_to_rcuwait(&vcpu->wait);
+	for (;;) {
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		if (kvm_vcpu_check_block(vcpu) < 0)
+			break;
+
+		waited = true;
+		schedule();
+	}
+	finish_rcuwait(&vcpu->wait);
+	cur = ktime_get();
+out:
+	kvm_arch_vcpu_unblocking(vcpu);
+	block_ns = ktime_to_ns(cur) - ktime_to_ns(start);
+
+	update_halt_poll_stats(
+		vcpu, ktime_to_ns(ktime_sub(poll_end, start)), waited);
+
+	if (!kvm_arch_no_poll(vcpu)) {
+		if (!vcpu_valid_wakeup(vcpu)) {
+			shrink_halt_poll_ns(vcpu);
+		} else if (vcpu->kvm->max_halt_poll_ns) {
+			if (block_ns <= vcpu->halt_poll_ns)
+				;
+			/* we had a long block, shrink polling */
+			else if (vcpu->halt_poll_ns &&
+					block_ns > vcpu->kvm->max_halt_poll_ns)
+				shrink_halt_poll_ns(vcpu);
+			/* we had a short halt and our poll time is too small */
+			else if (vcpu->halt_poll_ns < vcpu->kvm->max_halt_poll_ns &&
+					block_ns < vcpu->kvm->max_halt_poll_ns)
+				grow_halt_poll_ns(vcpu);
+		} else {
+			vcpu->halt_poll_ns = 0;
+		}
+	}
+
+	trace_kvm_vcpu_wakeup(block_ns, waited, vcpu_valid_wakeup(vcpu));
+	kvm_arch_vcpu_block_finish(vcpu);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_block);
+
+bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu)
+{
+	struct rcuwait *waitp;
+
+	waitp = kvm_arch_vcpu_get_wait(vcpu);
+	if (rcuwait_wake_up(waitp)) {
+		WRITE_ONCE(vcpu->ready, true);
+		++vcpu->stat.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;
+
+	/*
+	 * 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.
+	 */
+	me = get_cpu();
+	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);
+	}
+	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;
+}
+
+void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode)
+{
+	struct kvm *kvm = me->kvm;
+	struct kvm_vcpu *vcpu;
+	int last_boosted_vcpu = me->kvm->last_boosted_vcpu;
+	int yielded = 0;
+	int try = 3;
+	int pass;
+	int i;
+
+	kvm_vcpu_set_in_spin_loop(me, true);
+	/*
+	 * We boost the priority of a VCPU that is runnable but not
+	 * currently running, because it got preempted by something
+	 * else and called schedule in __vcpu_run.  Hopefully that
+	 * VCPU is holding the lock that we need and will release it.
+	 * We approximate round-robin by starting at the last boosted VCPU.
+	 */
+	for (pass = 0; pass < 2 && !yielded && try; pass++) {
+		kvm_for_each_vcpu(i, vcpu, kvm) {
+			if (!pass && i <= last_boosted_vcpu) {
+				i = last_boosted_vcpu;
+				continue;
+			} else if (pass && i > last_boosted_vcpu)
+				break;
+			if (!READ_ONCE(vcpu->ready))
+				continue;
+			if (vcpu == me)
+				continue;
+			if (rcuwait_active(&vcpu->wait) &&
+			    !vcpu_dy_runnable(vcpu))
+				continue;
+			if (READ_ONCE(vcpu->preempted) && yield_to_kernel_mode &&
+				!kvm_arch_vcpu_in_kernel(vcpu))
+				continue;
+			if (!kvm_vcpu_eligible_for_directed_yield(vcpu))
+				continue;
+
+			yielded = kvm_vcpu_yield_to(vcpu);
+			if (yielded > 0) {
+				kvm->last_boosted_vcpu = i;
+				break;
+			} else if (yielded < 0) {
+				try--;
+				if (!try)
+					break;
+			}
+		}
+	}
+	kvm_vcpu_set_in_spin_loop(me, false);
+
+	/* Ensure vcpu is not eligible during next spinloop */
+	kvm_vcpu_set_dy_eligible(me, false);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_on_spin);
+
+static vm_fault_t kvm_vcpu_fault(struct vm_fault *vmf)
+{
+	struct kvm_vcpu *vcpu = vmf->vma->vm_file->private_data;
+	struct page *page;
+
+	if (vmf->pgoff == 0)
+		page = virt_to_page(vcpu->run);
+#ifdef CONFIG_X86
+	else if (vmf->pgoff == KVM_PIO_PAGE_OFFSET)
+		page = virt_to_page(vcpu->arch.pio_data);
+#endif
+#ifdef CONFIG_KVM_MMIO
+	else if (vmf->pgoff == KVM_COALESCED_MMIO_PAGE_OFFSET)
+		page = virt_to_page(vcpu->kvm->coalesced_mmio_ring);
+#endif
+	else
+		return kvm_arch_vcpu_fault(vcpu, vmf);
+	get_page(page);
+	vmf->page = page;
+	return 0;
+}
+
+static const struct vm_operations_struct kvm_vcpu_vm_ops = {
+	.fault = kvm_vcpu_fault,
+};
+
+static int kvm_vcpu_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	vma->vm_ops = &kvm_vcpu_vm_ops;
+	return 0;
+}
+
+static int kvm_vcpu_release(struct inode *inode, struct file *filp)
+{
+	struct kvm_vcpu *vcpu = filp->private_data;
+
+	kvm_put_kvm(vcpu->kvm);
+	return 0;
+}
+
+static struct file_operations kvm_vcpu_fops = {
+	.release        = kvm_vcpu_release,
+	.unlocked_ioctl = kvm_vcpu_ioctl,
+	.mmap           = kvm_vcpu_mmap,
+	.llseek		= noop_llseek,
+	KVM_COMPAT(kvm_vcpu_compat_ioctl),
+};
+
+/*
+ * Allocates an inode for the vcpu.
+ */
+static int create_vcpu_fd(struct kvm_vcpu *vcpu)
+{
+	char name[8 + 1 + ITOA_MAX_LEN + 1];
+
+	snprintf(name, sizeof(name), "kvm-vcpu:%d", vcpu->vcpu_id);
+	return anon_inode_getfd(name, &kvm_vcpu_fops, vcpu, O_RDWR | O_CLOEXEC);
+}
+
+static void kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu)
+{
+#ifdef __KVM_HAVE_ARCH_VCPU_DEBUGFS
+	struct dentry *debugfs_dentry;
+	char dir_name[ITOA_MAX_LEN * 2];
+
+	if (!debugfs_initialized())
+		return;
+
+	snprintf(dir_name, sizeof(dir_name), "vcpu%d", vcpu->vcpu_id);
+	debugfs_dentry = debugfs_create_dir(dir_name,
+					    vcpu->kvm->debugfs_dentry);
+
+	kvm_arch_create_vcpu_debugfs(vcpu, debugfs_dentry);
+#endif
+}
+
+/*
+ * Creates some virtual cpus.  Good luck creating more than one.
+ */
+static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
+{
+	int r;
+	struct kvm_vcpu *vcpu;
+	struct page *page;
+
+	if (id >= KVM_MAX_VCPU_ID)
+		return -EINVAL;
+
+	mutex_lock(&kvm->lock);
+	if (kvm->created_vcpus == KVM_MAX_VCPUS) {
+		mutex_unlock(&kvm->lock);
+		return -EINVAL;
+	}
+
+	kvm->created_vcpus++;
+	mutex_unlock(&kvm->lock);
+
+	r = kvm_arch_vcpu_precreate(kvm, id);
+	if (r)
+		goto vcpu_decrement;
+
+	vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
+	if (!vcpu) {
+		r = -ENOMEM;
+		goto vcpu_decrement;
+	}
+
+	BUILD_BUG_ON(sizeof(struct kvm_run) > PAGE_SIZE);
+	page = alloc_page(GFP_KERNEL | __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;
+
+	mutex_lock(&kvm->lock);
+	if (kvm_get_vcpu_by_id(kvm, id)) {
+		r = -EEXIST;
+		goto unlock_vcpu_destroy;
+	}
+
+	vcpu->vcpu_idx = atomic_read(&kvm->online_vcpus);
+	BUG_ON(kvm->vcpus[vcpu->vcpu_idx]);
+
+	/* Now it's all set up, let userspace reach it */
+	kvm_get_kvm(kvm);
+	r = create_vcpu_fd(vcpu);
+	if (r < 0) {
+		kvm_put_kvm_no_destroy(kvm);
+		goto unlock_vcpu_destroy;
+	}
+
+	kvm->vcpus[vcpu->vcpu_idx] = vcpu;
+
+	/*
+	 * Pairs with smp_rmb() in kvm_get_vcpu.  Write kvm->vcpus
+	 * before kvm->online_vcpu's incremented value.
+	 */
+	smp_wmb();
+	atomic_inc(&kvm->online_vcpus);
+
+	mutex_unlock(&kvm->lock);
+	kvm_arch_vcpu_postcreate(vcpu);
+	kvm_create_vcpu_debugfs(vcpu);
+	return r;
+
+unlock_vcpu_destroy:
+	mutex_unlock(&kvm->lock);
+	kvm_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 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_bugged)
+		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;
+	}
+	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_bugged)
+		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_bugged)
+		return -EIO;
+
+	switch (ioctl) {
+	case KVM_SET_DEVICE_ATTR:
+		return kvm_device_ioctl_attr(dev, dev->ops->set_attr, arg);
+	case KVM_GET_DEVICE_ATTR:
+		return kvm_device_ioctl_attr(dev, dev->ops->get_attr, arg);
+	case KVM_HAS_DEVICE_ATTR:
+		return kvm_device_ioctl_attr(dev, dev->ops->has_attr, arg);
+	default:
+		if (dev->ops->ioctl)
+			return dev->ops->ioctl(dev, ioctl, arg);
+
+		return -ENOTTY;
+	}
+}
+
+static int kvm_device_release(struct inode *inode, struct file *filp)
+{
+	struct kvm_device *dev = filp->private_data;
+	struct kvm *kvm = dev->kvm;
+
+	if (dev->ops->release) {
+		mutex_lock(&kvm->lock);
+		list_del(&dev->vm_node);
+		dev->ops->release(dev);
+		mutex_unlock(&kvm->lock);
+	}
+
+	kvm_put_kvm(kvm);
+	return 0;
+}
+
+static const struct file_operations kvm_device_fops = {
+	.unlocked_ioctl = kvm_device_ioctl,
+	.release = kvm_device_release,
+	KVM_COMPAT(kvm_device_ioctl),
+	.mmap = kvm_device_mmap,
+};
+
+struct kvm_device *kvm_device_from_filp(struct file *filp)
+{
+	if (filp->f_op != &kvm_device_fops)
+		return NULL;
+
+	return filp->private_data;
+}
+
+static const struct kvm_device_ops *kvm_device_ops_table[KVM_DEV_TYPE_MAX] = {
+#ifdef CONFIG_KVM_MPIC
+	[KVM_DEV_TYPE_FSL_MPIC_20]	= &kvm_mpic_ops,
+	[KVM_DEV_TYPE_FSL_MPIC_42]	= &kvm_mpic_ops,
+#endif
+};
+
+int kvm_register_device_ops(const struct kvm_device_ops *ops, u32 type)
+{
+	if (type >= ARRAY_SIZE(kvm_device_ops_table))
+		return -ENOSPC;
+
+	if (kvm_device_ops_table[type] != NULL)
+		return -EEXIST;
+
+	kvm_device_ops_table[type] = ops;
+	return 0;
+}
+
+void kvm_unregister_device_ops(u32 type)
+{
+	if (kvm_device_ops_table[type] != NULL)
+		kvm_device_ops_table[type] = NULL;
+}
+
+static int kvm_ioctl_create_device(struct kvm *kvm,
+				   struct kvm_create_device *cd)
+{
+	const struct kvm_device_ops *ops = NULL;
+	struct kvm_device *dev;
+	bool test = cd->flags & KVM_CREATE_DEVICE_TEST;
+	int type;
+	int ret;
+
+	if (cd->type >= ARRAY_SIZE(kvm_device_ops_table))
+		return -ENODEV;
+
+	type = array_index_nospec(cd->type, ARRAY_SIZE(kvm_device_ops_table));
+	ops = kvm_device_ops_table[type];
+	if (ops == NULL)
+		return -ENODEV;
+
+	if (test)
+		return 0;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL_ACCOUNT);
+	if (!dev)
+		return -ENOMEM;
+
+	dev->ops = ops;
+	dev->kvm = kvm;
+
+	mutex_lock(&kvm->lock);
+	ret = ops->create(dev, type);
+	if (ret < 0) {
+		mutex_unlock(&kvm->lock);
+		kfree(dev);
+		return ret;
+	}
+	list_add(&dev->vm_node, &kvm->devices);
+	mutex_unlock(&kvm->lock);
+
+	if (ops->init)
+		ops->init(dev);
+
+	kvm_get_kvm(kvm);
+	ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC);
+	if (ret < 0) {
+		kvm_put_kvm_no_destroy(kvm);
+		mutex_lock(&kvm->lock);
+		list_del(&dev->vm_node);
+		if (ops->release)
+			ops->release(dev);
+		mutex_unlock(&kvm->lock);
+		if (ops->destroy)
+			ops->destroy(dev);
+		return ret;
+	}
+
+	cd->fd = ret;
+	return 0;
+}
+
+static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
+{
+	switch (arg) {
+	case KVM_CAP_USER_MEMORY:
+	case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
+	case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS:
+	case KVM_CAP_INTERNAL_ERROR_DATA:
+#ifdef CONFIG_HAVE_KVM_MSI
+	case KVM_CAP_SIGNAL_MSI:
+#endif
+#ifdef CONFIG_HAVE_KVM_IRQFD
+	case KVM_CAP_IRQFD:
+	case KVM_CAP_IRQFD_RESAMPLE:
+#endif
+	case KVM_CAP_IOEVENTFD_ANY_LENGTH:
+	case KVM_CAP_CHECK_EXTENSION_VM:
+	case KVM_CAP_ENABLE_CAP_VM:
+	case KVM_CAP_HALT_POLL:
+		return 1;
+#ifdef CONFIG_KVM_MMIO
+	case KVM_CAP_COALESCED_MMIO:
+		return KVM_COALESCED_MMIO_PAGE_OFFSET;
+	case KVM_CAP_COALESCED_PIO:
+		return 1;
+#endif
+#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
+	case KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2:
+		return KVM_DIRTY_LOG_MANUAL_CAPS;
+#endif
+#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
+	case KVM_CAP_IRQ_ROUTING:
+		return KVM_MAX_IRQ_ROUTES;
+#endif
+#if KVM_ADDRESS_SPACE_NUM > 1
+	case KVM_CAP_MULTI_ADDRESS_SPACE:
+		return KVM_ADDRESS_SPACE_NUM;
+#endif
+	case KVM_CAP_NR_MEMSLOTS:
+		return KVM_USER_MEM_SLOTS;
+	default:
+		break;
+	}
+	return kvm_vm_ioctl_check_extension(kvm, arg);
+}
+
+int __attribute__((weak)) kvm_vm_ioctl_enable_cap(struct kvm *kvm,
+						  struct kvm_enable_cap *cap)
+{
+	return -EINVAL;
+}
+
+static int kvm_vm_ioctl_enable_cap_generic(struct kvm *kvm,
+					   struct kvm_enable_cap *cap)
+{
+	switch (cap->cap) {
+#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
+	case KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2: {
+		u64 allowed_options = KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE;
+
+		if (cap->args[0] & KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE)
+			allowed_options = KVM_DIRTY_LOG_MANUAL_CAPS;
+
+		if (cap->flags || (cap->args[0] & ~allowed_options))
+			return -EINVAL;
+		kvm->manual_dirty_log_protect = cap->args[0];
+		return 0;
+	}
+#endif
+	case KVM_CAP_HALT_POLL: {
+		if (cap->flags || cap->args[0] != (unsigned int)cap->args[0])
+			return -EINVAL;
+
+		kvm->max_halt_poll_ns = cap->args[0];
+		return 0;
+	}
+	default:
+		return kvm_vm_ioctl_enable_cap(kvm, cap);
+	}
+}
+
+static long kvm_vm_ioctl(struct file *filp,
+			   unsigned int ioctl, unsigned long arg)
+{
+	struct kvm *kvm = filp->private_data;
+	void __user *argp = (void __user *)arg;
+	int r;
+
+	if (kvm->mm != current->mm || kvm->vm_bugged)
+		return -EIO;
+	switch (ioctl) {
+	case KVM_CREATE_VCPU:
+		r = kvm_vm_ioctl_create_vcpu(kvm, arg);
+		break;
+	case KVM_ENABLE_CAP: {
+		struct kvm_enable_cap cap;
+
+		r = -EFAULT;
+		if (copy_from_user(&cap, argp, sizeof(cap)))
+			goto out;
+		r = kvm_vm_ioctl_enable_cap_generic(kvm, &cap);
+		break;
+	}
+	case KVM_SET_USER_MEMORY_REGION: {
+		struct kvm_userspace_memory_region kvm_userspace_mem;
+
+		r = -EFAULT;
+		if (copy_from_user(&kvm_userspace_mem, argp,
+						sizeof(kvm_userspace_mem)))
+			goto out;
+
+		r = kvm_vm_ioctl_set_memory_region(kvm, &kvm_userspace_mem);
+		break;
+	}
+	case KVM_GET_DIRTY_LOG: {
+		struct kvm_dirty_log log;
+
+		r = -EFAULT;
+		if (copy_from_user(&log, argp, sizeof(log)))
+			goto out;
+		r = kvm_vm_ioctl_get_dirty_log(kvm, &log);
+		break;
+	}
+#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
+	case KVM_CLEAR_DIRTY_LOG: {
+		struct kvm_clear_dirty_log log;
+
+		r = -EFAULT;
+		if (copy_from_user(&log, argp, sizeof(log)))
+			goto out;
+		r = kvm_vm_ioctl_clear_dirty_log(kvm, &log);
+		break;
+	}
+#endif
+#ifdef CONFIG_KVM_MMIO
+	case KVM_REGISTER_COALESCED_MMIO: {
+		struct kvm_coalesced_mmio_zone zone;
+
+		r = -EFAULT;
+		if (copy_from_user(&zone, argp, sizeof(zone)))
+			goto out;
+		r = kvm_vm_ioctl_register_coalesced_mmio(kvm, &zone);
+		break;
+	}
+	case KVM_UNREGISTER_COALESCED_MMIO: {
+		struct kvm_coalesced_mmio_zone zone;
+
+		r = -EFAULT;
+		if (copy_from_user(&zone, argp, sizeof(zone)))
+			goto out;
+		r = kvm_vm_ioctl_unregister_coalesced_mmio(kvm, &zone);
+		break;
+	}
+#endif
+	case KVM_IRQFD: {
+		struct kvm_irqfd data;
+
+		r = -EFAULT;
+		if (copy_from_user(&data, argp, sizeof(data)))
+			goto out;
+		r = kvm_irqfd(kvm, &data);
+		break;
+	}
+	case KVM_IOEVENTFD: {
+		struct kvm_ioeventfd data;
+
+		r = -EFAULT;
+		if (copy_from_user(&data, argp, sizeof(data)))
+			goto out;
+		r = kvm_ioeventfd(kvm, &data);
+		break;
+	}
+#ifdef CONFIG_HAVE_KVM_MSI
+	case KVM_SIGNAL_MSI: {
+		struct kvm_msi msi;
+
+		r = -EFAULT;
+		if (copy_from_user(&msi, argp, sizeof(msi)))
+			goto out;
+		r = kvm_send_userspace_msi(kvm, &msi);
+		break;
+	}
+#endif
+#ifdef __KVM_HAVE_IRQ_LINE
+	case KVM_IRQ_LINE_STATUS:
+	case KVM_IRQ_LINE: {
+		struct kvm_irq_level irq_event;
+
+		r = -EFAULT;
+		if (copy_from_user(&irq_event, argp, sizeof(irq_event)))
+			goto out;
+
+		r = kvm_vm_ioctl_irq_line(kvm, &irq_event,
+					ioctl == KVM_IRQ_LINE_STATUS);
+		if (r)
+			goto out;
+
+		r = -EFAULT;
+		if (ioctl == KVM_IRQ_LINE_STATUS) {
+			if (copy_to_user(argp, &irq_event, sizeof(irq_event)))
+				goto out;
+		}
+
+		r = 0;
+		break;
+	}
+#endif
+#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
+	case KVM_SET_GSI_ROUTING: {
+		struct kvm_irq_routing routing;
+		struct kvm_irq_routing __user *urouting;
+		struct kvm_irq_routing_entry *entries = NULL;
+
+		r = -EFAULT;
+		if (copy_from_user(&routing, argp, sizeof(routing)))
+			goto out;
+		r = -EINVAL;
+		if (!kvm_arch_can_set_irq_routing(kvm))
+			goto out;
+		if (routing.nr > KVM_MAX_IRQ_ROUTES)
+			goto out;
+		if (routing.flags)
+			goto out;
+		if (routing.nr) {
+			urouting = argp;
+			entries = vmemdup_user(urouting->entries,
+					       array_size(sizeof(*entries),
+							  routing.nr));
+			if (IS_ERR(entries)) {
+				r = PTR_ERR(entries);
+				goto out;
+			}
+		}
+		r = kvm_set_irq_routing(kvm, entries, routing.nr,
+					routing.flags);
+		kvfree(entries);
+		break;
+	}
+#endif /* CONFIG_HAVE_KVM_IRQ_ROUTING */
+	case KVM_CREATE_DEVICE: {
+		struct kvm_create_device cd;
+
+		r = -EFAULT;
+		if (copy_from_user(&cd, argp, sizeof(cd)))
+			goto out;
+
+		r = kvm_ioctl_create_device(kvm, &cd);
+		if (r)
+			goto out;
+
+		r = -EFAULT;
+		if (copy_to_user(argp, &cd, sizeof(cd)))
+			goto out;
+
+		r = 0;
+		break;
+	}
+	case KVM_CHECK_EXTENSION:
+		r = kvm_vm_ioctl_check_extension_generic(kvm, arg);
+		break;
+	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_bugged)
+		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),
+};
+
+static int kvm_dev_ioctl_create_vm(unsigned long type)
+{
+	int r;
+	struct kvm *kvm;
+	struct file *file;
+
+	kvm = kvm_create_vm(type);
+	if (IS_ERR(kvm))
+		return PTR_ERR(kvm);
+#ifdef CONFIG_KVM_MMIO
+	r = kvm_coalesced_mmio_init(kvm);
+	if (r < 0)
+		goto put_kvm;
+#endif
+	r = get_unused_fd_flags(O_CLOEXEC);
+	if (r < 0)
+		goto put_kvm;
+
+	file = anon_inode_getfile("kvm-vm", &kvm_vm_fops, kvm, O_RDWR);
+	if (IS_ERR(file)) {
+		put_unused_fd(r);
+		r = PTR_ERR(file);
+		goto put_kvm;
+	}
+
+	/*
+	 * Don't call kvm_put_kvm anymore at this point; file->f_op is
+	 * already set, with ->release() being kvm_vm_release().  In error
+	 * cases it will be called by the final fput(file) and will take
+	 * care of doing kvm_put_kvm(kvm).
+	 */
+	if (kvm_create_vm_debugfs(kvm, r) < 0) {
+		put_unused_fd(r);
+		fput(file);
+		return -ENOMEM;
+	}
+	kvm_uevent_notify_change(KVM_EVENT_CREATE_VM, kvm);
+
+	fd_install(r, file);
+	return r;
+
+put_kvm:
+	kvm_put_kvm(kvm);
+	return r;
+}
+
+static long kvm_dev_ioctl(struct file *filp,
+			  unsigned int ioctl, unsigned long arg)
+{
+	long r = -EINVAL;
+
+	switch (ioctl) {
+	case KVM_GET_API_VERSION:
+		if (arg)
+			goto out;
+		r = KVM_API_VERSION;
+		break;
+	case KVM_CREATE_VM:
+		r = kvm_dev_ioctl_create_vm(arg);
+		break;
+	case KVM_CHECK_EXTENSION:
+		r = kvm_vm_ioctl_check_extension_generic(NULL, arg);
+		break;
+	case KVM_GET_VCPU_MMAP_SIZE:
+		if (arg)
+			goto out;
+		r = PAGE_SIZE;     /* struct kvm_run */
+#ifdef CONFIG_X86
+		r += PAGE_SIZE;    /* pio data page */
+#endif
+#ifdef CONFIG_KVM_MMIO
+		r += PAGE_SIZE;    /* coalesced mmio ring page */
+#endif
+		break;
+	case KVM_TRACE_ENABLE:
+	case KVM_TRACE_PAUSE:
+	case KVM_TRACE_DISABLE:
+		r = -EOPNOTSUPP;
+		break;
+	default:
+		return kvm_arch_dev_ioctl(filp, ioctl, arg);
+	}
+out:
+	return r;
+}
+
+static struct file_operations kvm_chardev_ops = {
+	.unlocked_ioctl = kvm_dev_ioctl,
+	.llseek		= noop_llseek,
+	KVM_COMPAT(kvm_dev_ioctl),
+};
+
+static struct miscdevice kvm_dev = {
+	KVM_MINOR,
+	"kvm",
+	&kvm_chardev_ops,
+};
+
+static void hardware_enable_nolock(void *junk)
+{
+	int cpu = raw_smp_processor_id();
+	int r;
+
+	if (cpumask_test_cpu(cpu, cpus_hardware_enabled))
+		return;
+
+	cpumask_set_cpu(cpu, cpus_hardware_enabled);
+
+	r = kvm_arch_hardware_enable();
+
+	if (r) {
+		cpumask_clear_cpu(cpu, cpus_hardware_enabled);
+		atomic_inc(&hardware_enable_failed);
+		pr_info("kvm: enabling virtualization on CPU%d failed\n", cpu);
+	}
+}
+
+static int kvm_starting_cpu(unsigned int cpu)
+{
+	raw_spin_lock(&kvm_count_lock);
+	if (kvm_usage_count)
+		hardware_enable_nolock(NULL);
+	raw_spin_unlock(&kvm_count_lock);
+	return 0;
+}
+
+static void hardware_disable_nolock(void *junk)
+{
+	int cpu = raw_smp_processor_id();
+
+	if (!cpumask_test_cpu(cpu, cpus_hardware_enabled))
+		return;
+	cpumask_clear_cpu(cpu, cpus_hardware_enabled);
+	kvm_arch_hardware_disable();
+}
+
+static int kvm_dying_cpu(unsigned int cpu)
+{
+	raw_spin_lock(&kvm_count_lock);
+	if (kvm_usage_count)
+		hardware_disable_nolock(NULL);
+	raw_spin_unlock(&kvm_count_lock);
+	return 0;
+}
+
+static void hardware_disable_all_nolock(void)
+{
+	BUG_ON(!kvm_usage_count);
+
+	kvm_usage_count--;
+	if (!kvm_usage_count)
+		on_each_cpu(hardware_disable_nolock, NULL, 1);
+}
+
+static void hardware_disable_all(void)
+{
+	raw_spin_lock(&kvm_count_lock);
+	hardware_disable_all_nolock();
+	raw_spin_unlock(&kvm_count_lock);
+}
+
+static int hardware_enable_all(void)
+{
+	int r = 0;
+
+	raw_spin_lock(&kvm_count_lock);
+
+	kvm_usage_count++;
+	if (kvm_usage_count == 1) {
+		atomic_set(&hardware_enable_failed, 0);
+		on_each_cpu(hardware_enable_nolock, NULL, 1);
+
+		if (atomic_read(&hardware_enable_failed)) {
+			hardware_disable_all_nolock();
+			r = -EBUSY;
+		}
+	}
+
+	raw_spin_unlock(&kvm_count_lock);
+
+	return r;
+}
+
+static int kvm_reboot(struct notifier_block *notifier, unsigned long val,
+		      void *v)
+{
+	/*
+	 * Some (well, at least mine) BIOSes hang on reboot if
+	 * in vmx root mode.
+	 *
+	 * And Intel TXT required VMX off for all cpu when system shutdown.
+	 */
+	pr_info("kvm: exiting hardware virtualization\n");
+	kvm_rebooting = true;
+	on_each_cpu(hardware_disable_nolock, NULL, 1);
+	return NOTIFY_OK;
+}
+
+static struct notifier_block kvm_reboot_notifier = {
+	.notifier_call = kvm_reboot,
+	.priority = 0,
+};
+
+static void kvm_io_bus_destroy(struct kvm_io_bus *bus)
+{
+	int i;
+
+	for (i = 0; i < bus->dev_count; i++) {
+		struct kvm_io_device *pos = bus->range[i].dev;
+
+		kvm_iodevice_destructor(pos);
+	}
+	kfree(bus);
+}
+
+static inline int kvm_io_bus_cmp(const struct kvm_io_range *r1,
+				 const struct kvm_io_range *r2)
+{
+	gpa_t addr1 = r1->addr;
+	gpa_t addr2 = r2->addr;
+
+	if (addr1 < addr2)
+		return -1;
+
+	/* If r2->len == 0, match the exact address.  If r2->len != 0,
+	 * accept any overlapping write.  Any order is acceptable for
+	 * overlapping ranges, because kvm_io_bus_get_first_dev ensures
+	 * we process all of them.
+	 */
+	if (r2->len) {
+		addr1 += r1->len;
+		addr2 += r2->len;
+	}
+
+	if (addr1 > addr2)
+		return 1;
+
+	return 0;
+}
+
+static int kvm_io_bus_sort_cmp(const void *p1, const void *p2)
+{
+	return kvm_io_bus_cmp(p1, p2);
+}
+
+static int kvm_io_bus_get_first_dev(struct kvm_io_bus *bus,
+			     gpa_t addr, int len)
+{
+	struct kvm_io_range *range, key;
+	int off;
+
+	key = (struct kvm_io_range) {
+		.addr = addr,
+		.len = len,
+	};
+
+	range = bsearch(&key, bus->range, bus->dev_count,
+			sizeof(struct kvm_io_range), kvm_io_bus_sort_cmp);
+	if (range == NULL)
+		return -ENOENT;
+
+	off = range - bus->range;
+
+	while (off > 0 && kvm_io_bus_cmp(&key, &bus->range[off-1]) == 0)
+		off--;
+
+	return off;
+}
+
+static int __kvm_io_bus_write(struct kvm_vcpu *vcpu, struct kvm_io_bus *bus,
+			      struct kvm_io_range *range, const void *val)
+{
+	int idx;
+
+	idx = kvm_io_bus_get_first_dev(bus, range->addr, range->len);
+	if (idx < 0)
+		return -EOPNOTSUPP;
+
+	while (idx < bus->dev_count &&
+		kvm_io_bus_cmp(range, &bus->range[idx]) == 0) {
+		if (!kvm_iodevice_write(vcpu, bus->range[idx].dev, range->addr,
+					range->len, val))
+			return idx;
+		idx++;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+/* kvm_io_bus_write - called under kvm->slots_lock */
+int kvm_io_bus_write(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr,
+		     int len, const void *val)
+{
+	struct kvm_io_bus *bus;
+	struct kvm_io_range range;
+	int r;
+
+	range = (struct kvm_io_range) {
+		.addr = addr,
+		.len = len,
+	};
+
+	bus = srcu_dereference(vcpu->kvm->buses[bus_idx], &vcpu->kvm->srcu);
+	if (!bus)
+		return -ENOMEM;
+	r = __kvm_io_bus_write(vcpu, bus, &range, val);
+	return r < 0 ? r : 0;
+}
+EXPORT_SYMBOL_GPL(kvm_io_bus_write);
+
+/* kvm_io_bus_write_cookie - called under kvm->slots_lock */
+int kvm_io_bus_write_cookie(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx,
+			    gpa_t addr, int len, const void *val, long cookie)
+{
+	struct kvm_io_bus *bus;
+	struct kvm_io_range range;
+
+	range = (struct kvm_io_range) {
+		.addr = addr,
+		.len = len,
+	};
+
+	bus = srcu_dereference(vcpu->kvm->buses[bus_idx], &vcpu->kvm->srcu);
+	if (!bus)
+		return -ENOMEM;
+
+	/* First try the device referenced by cookie. */
+	if ((cookie >= 0) && (cookie < bus->dev_count) &&
+	    (kvm_io_bus_cmp(&range, &bus->range[cookie]) == 0))
+		if (!kvm_iodevice_write(vcpu, bus->range[cookie].dev, addr, len,
+					val))
+			return cookie;
+
+	/*
+	 * cookie contained garbage; fall back to search and return the
+	 * correct cookie value.
+	 */
+	return __kvm_io_bus_write(vcpu, bus, &range, val);
+}
+
+static int __kvm_io_bus_read(struct kvm_vcpu *vcpu, struct kvm_io_bus *bus,
+			     struct kvm_io_range *range, void *val)
+{
+	int idx;
+
+	idx = kvm_io_bus_get_first_dev(bus, range->addr, range->len);
+	if (idx < 0)
+		return -EOPNOTSUPP;
+
+	while (idx < bus->dev_count &&
+		kvm_io_bus_cmp(range, &bus->range[idx]) == 0) {
+		if (!kvm_iodevice_read(vcpu, bus->range[idx].dev, range->addr,
+				       range->len, val))
+			return idx;
+		idx++;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+/* kvm_io_bus_read - called under kvm->slots_lock */
+int kvm_io_bus_read(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr,
+		    int len, void *val)
+{
+	struct kvm_io_bus *bus;
+	struct kvm_io_range range;
+	int r;
+
+	range = (struct kvm_io_range) {
+		.addr = addr,
+		.len = len,
+	};
+
+	bus = srcu_dereference(vcpu->kvm->buses[bus_idx], &vcpu->kvm->srcu);
+	if (!bus)
+		return -ENOMEM;
+	r = __kvm_io_bus_read(vcpu, bus, &range, val);
+	return r < 0 ? r : 0;
+}
+
+/* Caller must hold slots_lock. */
+int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
+			    int len, struct kvm_io_device *dev)
+{
+	int i;
+	struct kvm_io_bus *new_bus, *bus;
+	struct kvm_io_range range;
+
+	bus = kvm_get_bus(kvm, bus_idx);
+	if (!bus)
+		return -ENOMEM;
+
+	/* exclude ioeventfd which is limited by maximum fd */
+	if (bus->dev_count - bus->ioeventfd_count > NR_IOBUS_DEVS - 1)
+		return -ENOSPC;
+
+	new_bus = kmalloc(struct_size(bus, range, bus->dev_count + 1),
+			  GFP_KERNEL_ACCOUNT);
+	if (!new_bus)
+		return -ENOMEM;
+
+	range = (struct kvm_io_range) {
+		.addr = addr,
+		.len = len,
+		.dev = dev,
+	};
+
+	for (i = 0; i < bus->dev_count; i++)
+		if (kvm_io_bus_cmp(&bus->range[i], &range) > 0)
+			break;
+
+	memcpy(new_bus, bus, sizeof(*bus) + i * sizeof(struct kvm_io_range));
+	new_bus->dev_count++;
+	new_bus->range[i] = range;
+	memcpy(new_bus->range + i + 1, bus->range + i,
+		(bus->dev_count - i) * sizeof(struct kvm_io_range));
+	rcu_assign_pointer(kvm->buses[bus_idx], new_bus);
+	synchronize_srcu_expedited(&kvm->srcu);
+	kfree(bus);
+
+	return 0;
+}
+
+/* Caller must hold slots_lock. */
+int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
+			      struct kvm_io_device *dev)
+{
+	int i, j;
+	struct kvm_io_bus *new_bus, *bus;
+
+	bus = kvm_get_bus(kvm, bus_idx);
+	if (!bus)
+		return 0;
+
+	for (i = 0; i < bus->dev_count; i++)
+		if (bus->range[i].dev == dev) {
+			break;
+		}
+
+	if (i == bus->dev_count)
+		return 0;
+
+	new_bus = kmalloc(struct_size(bus, range, bus->dev_count - 1),
+			  GFP_KERNEL_ACCOUNT);
+	if (new_bus) {
+		memcpy(new_bus, bus, struct_size(bus, range, i));
+		new_bus->dev_count--;
+		memcpy(new_bus->range + i, bus->range + i + 1,
+				flex_array_size(new_bus, range, new_bus->dev_count - i));
+	}
+
+	rcu_assign_pointer(kvm->buses[bus_idx], new_bus);
+	synchronize_srcu_expedited(&kvm->srcu);
+
+	/* Destroy the old bus _after_ installing the (null) bus. */
+	if (!new_bus) {
+		pr_err("kvm: failed to shrink bus, removing it completely\n");
+		for (j = 0; j < bus->dev_count; j++) {
+			if (j == i)
+				continue;
+			kvm_iodevice_destructor(bus->range[j].dev);
+		}
+	}
+
+	kfree(bus);
+	return new_bus ? 0 : -ENOMEM;
+}
+
+struct kvm_io_device *kvm_io_bus_get_dev(struct kvm *kvm, enum kvm_bus bus_idx,
+					 gpa_t addr)
+{
+	struct kvm_io_bus *bus;
+	int dev_idx, srcu_idx;
+	struct kvm_io_device *iodev = NULL;
+
+	srcu_idx = srcu_read_lock(&kvm->srcu);
+
+	bus = srcu_dereference(kvm->buses[bus_idx], &kvm->srcu);
+	if (!bus)
+		goto out_unlock;
+
+	dev_idx = kvm_io_bus_get_first_dev(bus, addr, 1);
+	if (dev_idx < 0)
+		goto out_unlock;
+
+	iodev = bus->range[dev_idx].dev;
+
+out_unlock:
+	srcu_read_unlock(&kvm->srcu, srcu_idx);
+
+	return iodev;
+}
+EXPORT_SYMBOL_GPL(kvm_io_bus_get_dev);
+
+static int kvm_debugfs_open(struct inode *inode, struct file *file,
+			   int (*get)(void *, u64 *), int (*set)(void *, u64),
+			   const char *fmt)
+{
+	struct kvm_stat_data *stat_data = (struct kvm_stat_data *)
+					  inode->i_private;
+
+	/* The debugfs files are a reference to the kvm struct which
+	 * is still valid when kvm_destroy_vm is called.
+	 * To avoid the race between open and the removal of the debugfs
+	 * directory we test against the users count.
+	 */
+	if (!refcount_inc_not_zero(&stat_data->kvm->users_count))
+		return -ENOENT;
+
+	if (simple_attr_open(inode, file, get,
+		    KVM_DBGFS_GET_MODE(stat_data->dbgfs_item) & 0222
+		    ? set : NULL,
+		    fmt)) {
+		kvm_put_kvm(stat_data->kvm);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int kvm_debugfs_release(struct inode *inode, struct file *file)
+{
+	struct kvm_stat_data *stat_data = (struct kvm_stat_data *)
+					  inode->i_private;
+
+	simple_attr_release(inode, file);
+	kvm_put_kvm(stat_data->kvm);
+
+	return 0;
+}
+
+static int kvm_get_stat_per_vm(struct kvm *kvm, size_t offset, u64 *val)
+{
+	*val = *(ulong *)((void *)kvm + offset);
+
+	return 0;
+}
+
+static int kvm_clear_stat_per_vm(struct kvm *kvm, size_t offset)
+{
+	*(ulong *)((void *)kvm + offset) = 0;
+
+	return 0;
+}
+
+static int kvm_get_stat_per_vcpu(struct kvm *kvm, size_t offset, u64 *val)
+{
+	int i;
+	struct kvm_vcpu *vcpu;
+
+	*val = 0;
+
+	kvm_for_each_vcpu(i, vcpu, kvm)
+		*val += *(u64 *)((void *)vcpu + offset);
+
+	return 0;
+}
+
+static int kvm_clear_stat_per_vcpu(struct kvm *kvm, size_t offset)
+{
+	int i;
+	struct kvm_vcpu *vcpu;
+
+	kvm_for_each_vcpu(i, vcpu, kvm)
+		*(u64 *)((void *)vcpu + offset) = 0;
+
+	return 0;
+}
+
+static int kvm_stat_data_get(void *data, u64 *val)
+{
+	int r = -EFAULT;
+	struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
+
+	switch (stat_data->dbgfs_item->kind) {
+	case KVM_STAT_VM:
+		r = kvm_get_stat_per_vm(stat_data->kvm,
+					stat_data->dbgfs_item->offset, val);
+		break;
+	case KVM_STAT_VCPU:
+		r = kvm_get_stat_per_vcpu(stat_data->kvm,
+					  stat_data->dbgfs_item->offset, val);
+		break;
+	}
+
+	return r;
+}
+
+static int kvm_stat_data_clear(void *data, u64 val)
+{
+	int r = -EFAULT;
+	struct kvm_stat_data *stat_data = (struct kvm_stat_data *)data;
+
+	if (val)
+		return -EINVAL;
+
+	switch (stat_data->dbgfs_item->kind) {
+	case KVM_STAT_VM:
+		r = kvm_clear_stat_per_vm(stat_data->kvm,
+					  stat_data->dbgfs_item->offset);
+		break;
+	case KVM_STAT_VCPU:
+		r = kvm_clear_stat_per_vcpu(stat_data->kvm,
+					    stat_data->dbgfs_item->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");
+
+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");
+
+static const struct file_operations *stat_fops[] = {
+	[KVM_STAT_VCPU] = &vcpu_stat_fops,
+	[KVM_STAT_VM]   = &vm_stat_fops,
+};
+
+static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm)
+{
+	struct kobj_uevent_env *env;
+	unsigned long long created, active;
+
+	if (!kvm_dev.this_device || !kvm)
+		return;
+
+	mutex_lock(&kvm_lock);
+	if (type == KVM_EVENT_CREATE_VM) {
+		kvm_createvm_count++;
+		kvm_active_vms++;
+	} else if (type == KVM_EVENT_DESTROY_VM) {
+		kvm_active_vms--;
+	}
+	created = kvm_createvm_count;
+	active = kvm_active_vms;
+	mutex_unlock(&kvm_lock);
+
+	env = kzalloc(sizeof(*env), GFP_KERNEL_ACCOUNT);
+	if (!env)
+		return;
+
+	add_uevent_var(env, "CREATED=%llu", created);
+	add_uevent_var(env, "COUNT=%llu", active);
+
+	if (type == KVM_EVENT_CREATE_VM) {
+		add_uevent_var(env, "EVENT=create");
+		kvm->userspace_pid = task_pid_nr(current);
+	} else if (type == KVM_EVENT_DESTROY_VM) {
+		add_uevent_var(env, "EVENT=destroy");
+	}
+	add_uevent_var(env, "PID=%d", kvm->userspace_pid);
+
+	if (kvm->debugfs_dentry) {
+		char *tmp, *p = kmalloc(PATH_MAX, GFP_KERNEL_ACCOUNT);
+
+		if (p) {
+			tmp = dentry_path_raw(kvm->debugfs_dentry, p, PATH_MAX);
+			if (!IS_ERR(tmp))
+				add_uevent_var(env, "STATS_PATH=%s", tmp);
+			kfree(p);
+		}
+	}
+	/* no need for checks, since we are adding at most only 5 keys */
+	env->envp[env->envp_idx++] = NULL;
+	kobject_uevent_env(&kvm_dev.this_device->kobj, KOBJ_CHANGE, env->envp);
+	kfree(env);
+}
+
+static void kvm_init_debug(void)
+{
+	struct kvm_stats_debugfs_item *p;
+
+	kvm_debugfs_dir = debugfs_create_dir("kvm", NULL);
+
+	kvm_debugfs_num_entries = 0;
+	for (p = debugfs_entries; p->name; ++p, kvm_debugfs_num_entries++) {
+		debugfs_create_file(p->name, KVM_DBGFS_GET_MODE(p),
+				    kvm_debugfs_dir, (void *)(long)p->offset,
+				    stat_fops[p->kind]);
+	}
+}
+
+static int kvm_suspend(void)
+{
+	if (kvm_usage_count)
+		hardware_disable_nolock(NULL);
+	return 0;
+}
+
+static void kvm_resume(void)
+{
+	if (kvm_usage_count) {
+#ifdef CONFIG_LOCKDEP
+		WARN_ON(lockdep_is_held(&kvm_count_lock));
+#endif
+		hardware_enable_nolock(NULL);
+	}
+}
+
+static struct syscore_ops kvm_syscore_ops = {
+	.suspend = kvm_suspend,
+	.resume = kvm_resume,
+};
+
+static inline
+struct kvm_vcpu *preempt_notifier_to_vcpu(struct preempt_notifier *pn)
+{
+	return container_of(pn, struct kvm_vcpu, preempt_notifier);
+}
+
+static void kvm_sched_in(struct preempt_notifier *pn, int cpu)
+{
+	struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);
+
+	WRITE_ONCE(vcpu->preempted, false);
+	WRITE_ONCE(vcpu->ready, false);
+
+	__this_cpu_write(kvm_running_vcpu, vcpu);
+	kvm_arch_sched_in(vcpu, cpu);
+	kvm_arch_vcpu_load(vcpu, cpu);
+}
+
+static void kvm_sched_out(struct preempt_notifier *pn,
+			  struct task_struct *next)
+{
+	struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);
+
+	if (current->state == TASK_RUNNING) {
+		WRITE_ONCE(vcpu->preempted, true);
+		WRITE_ONCE(vcpu->ready, true);
+	}
+	kvm_arch_vcpu_put(vcpu);
+	__this_cpu_write(kvm_running_vcpu, NULL);
+}
+
+/**
+ * kvm_get_running_vcpu - get the vcpu running on the current CPU.
+ *
+ * We can disable preemption locally around accessing the per-CPU variable,
+ * and use the resolved vcpu pointer after enabling preemption again,
+ * because even if the current thread is migrated to another CPU, reading
+ * the per-CPU value later will give us the same value as we update the
+ * per-CPU variable in the preempt notifier handlers.
+ */
+struct kvm_vcpu *kvm_get_running_vcpu(void)
+{
+	struct kvm_vcpu *vcpu;
+
+	preempt_disable();
+	vcpu = __this_cpu_read(kvm_running_vcpu);
+	preempt_enable();
+
+	return vcpu;
+}
+EXPORT_SYMBOL_GPL(kvm_get_running_vcpu);
+
+/**
+ * kvm_get_running_vcpus - get the per-CPU array of currently running vcpus.
+ */
+struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void)
+{
+        return &kvm_running_vcpu;
+}
+
+struct kvm_cpu_compat_check {
+	void *opaque;
+	int *ret;
+};
+
+static void check_processor_compat(void *data)
+{
+	struct kvm_cpu_compat_check *c = data;
+
+	*c->ret = kvm_arch_check_processor_compat(c->opaque);
+}
+
+int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
+		  struct module *module)
+{
+	struct kvm_cpu_compat_check c;
+	int r;
+	int cpu;
+
+	r = kvm_arch_init(opaque);
+	if (r)
+		goto out_fail;
+
+	/*
+	 * kvm_arch_init makes sure there's at most one caller
+	 * for architectures that support multiple implementations,
+	 * like intel and amd on x86.
+	 * kvm_arch_init must be called before kvm_irqfd_init to avoid creating
+	 * conflicts in case kvm is already setup for another implementation.
+	 */
+	r = kvm_irqfd_init();
+	if (r)
+		goto out_irqfd;
+
+	if (!zalloc_cpumask_var(&cpus_hardware_enabled, GFP_KERNEL)) {
+		r = -ENOMEM;
+		goto out_free_0;
+	}
+
+	r = kvm_arch_hardware_setup(opaque);
+	if (r < 0)
+		goto out_free_1;
+
+	c.ret = &r;
+	c.opaque = opaque;
+	for_each_online_cpu(cpu) {
+		smp_call_function_single(cpu, check_processor_compat, &c, 1);
+		if (r < 0)
+			goto out_free_2;
+	}
+
+	r = cpuhp_setup_state_nocalls(CPUHP_AP_KVM_STARTING, "kvm/cpu:starting",
+				      kvm_starting_cpu, kvm_dying_cpu);
+	if (r)
+		goto out_free_2;
+	register_reboot_notifier(&kvm_reboot_notifier);
+
+	/* A kmem cache lets us meet the alignment requirements of fx_save. */
+	if (!vcpu_align)
+		vcpu_align = __alignof__(struct kvm_vcpu);
+	kvm_vcpu_cache =
+		kmem_cache_create_usercopy("kvm_vcpu", vcpu_size, vcpu_align,
+					   SLAB_ACCOUNT,
+					   offsetof(struct kvm_vcpu, arch),
+					   sizeof_field(struct kvm_vcpu, arch),
+					   NULL);
+	if (!kvm_vcpu_cache) {
+		r = -ENOMEM;
+		goto out_free_3;
+	}
+
+	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 out_free_4;
+		}
+	}
+
+	r = kvm_async_pf_init();
+	if (r)
+		goto out_free_4;
+
+	kvm_chardev_ops.owner = module;
+	kvm_vm_fops.owner = module;
+	kvm_vcpu_fops.owner = module;
+
+	register_syscore_ops(&kvm_syscore_ops);
+
+	kvm_preempt_ops.sched_in = kvm_sched_in;
+	kvm_preempt_ops.sched_out = kvm_sched_out;
+
+	kvm_init_debug();
+
+	r = kvm_vfio_ops_init();
+	if (WARN_ON_ONCE(r))
+		goto err_vfio;
+
+	/*
+	 * 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();
+out_free_4:
+	for_each_possible_cpu(cpu)
+		free_cpumask_var(per_cpu(cpu_kick_mask, cpu));
+	kmem_cache_destroy(kvm_vcpu_cache);
+out_free_3:
+	unregister_reboot_notifier(&kvm_reboot_notifier);
+	cpuhp_remove_state_nocalls(CPUHP_AP_KVM_STARTING);
+out_free_2:
+	kvm_arch_hardware_unsetup();
+out_free_1:
+	free_cpumask_var(cpus_hardware_enabled);
+out_free_0:
+	kvm_irqfd_exit();
+out_irqfd:
+	kvm_arch_exit();
+out_fail:
+	return r;
+}
+EXPORT_SYMBOL_GPL(kvm_init);
+
+void kvm_exit(void)
+{
+	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_async_pf_deinit();
+	unregister_syscore_ops(&kvm_syscore_ops);
+	unregister_reboot_notifier(&kvm_reboot_notifier);
+	cpuhp_remove_state_nocalls(CPUHP_AP_KVM_STARTING);
+	on_each_cpu(hardware_disable_nolock, NULL, 1);
+	kvm_arch_hardware_unsetup();
+	kvm_arch_exit();
+	kvm_irqfd_exit();
+	free_cpumask_var(cpus_hardware_enabled);
+	kvm_vfio_ops_exit();
+}
+EXPORT_SYMBOL_GPL(kvm_exit);
+
+struct kvm_vm_worker_thread_context {
+	struct kvm *kvm;
+	struct task_struct *parent;
+	struct completion init_done;
+	kvm_vm_thread_fn_t thread_fn;
+	uintptr_t data;
+	int err;
+};
+
+static int kvm_vm_worker_thread(void *context)
+{
+	/*
+	 * The init_context is allocated on the stack of the parent thread, so
+	 * we have to locally copy anything that is needed beyond initialization
+	 */
+	struct kvm_vm_worker_thread_context *init_context = context;
+	struct kvm *kvm = init_context->kvm;
+	kvm_vm_thread_fn_t thread_fn = init_context->thread_fn;
+	uintptr_t data = init_context->data;
+	int err;
+
+	err = kthread_park(current);
+	/* kthread_park(current) is never supposed to return an error */
+	WARN_ON(err != 0);
+	if (err)
+		goto init_complete;
+
+	err = cgroup_attach_task_all(init_context->parent, current);
+	if (err) {
+		kvm_err("%s: cgroup_attach_task_all failed with err %d\n",
+			__func__, err);
+		goto init_complete;
+	}
+
+	set_user_nice(current, task_nice(init_context->parent));
+
+init_complete:
+	init_context->err = err;
+	complete(&init_context->init_done);
+	init_context = NULL;
+
+	if (err)
+		return err;
+
+	/* Wait to be woken up by the spawner before proceeding. */
+	kthread_parkme();
+
+	if (!kthread_should_stop())
+		err = thread_fn(kvm, data);
+
+	return err;
+}
+
+int kvm_vm_create_worker_thread(struct kvm *kvm, kvm_vm_thread_fn_t thread_fn,
+				uintptr_t data, const char *name,
+				struct task_struct **thread_ptr)
+{
+	struct kvm_vm_worker_thread_context init_context = {};
+	struct task_struct *thread;
+
+	*thread_ptr = NULL;
+	init_context.kvm = kvm;
+	init_context.parent = current;
+	init_context.thread_fn = thread_fn;
+	init_context.data = data;
+	init_completion(&init_context.init_done);
+
+	thread = kthread_run(kvm_vm_worker_thread, &init_context,
+			     "%s-%d", name, task_pid_nr(current));
+	if (IS_ERR(thread))
+		return PTR_ERR(thread);
+
+	/* kthread_run is never supposed to return NULL */
+	WARN_ON(thread == NULL);
+
+	wait_for_completion(&init_context.init_done);
+
+	if (!init_context.err)
+		*thread_ptr = thread;
+
+	return init_context.err;
+}