blob: 383df23514b9390c467379ec9a739eda14a72bf2 [file] [log] [blame]
// 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 "mmu_lock.h"
#include "vfio.h"
#define CREATE_TRACE_POINTS
#include <trace/events/kvm.h>
#include <linux/kvm_dirty_ring.h>
/* Worst case buffer size needed for holding an integer. */
#define ITOA_MAX_LEN 12
MODULE_AUTHOR("Qumranet");
MODULE_LICENSE("GPL");
/* Architectures should define their poll value according to the halt latency */
unsigned int halt_poll_ns = KVM_HALT_POLL_NS_DEFAULT;
module_param(halt_poll_ns, uint, 0644);
EXPORT_SYMBOL_GPL(halt_poll_ns);
/* Default doubles per-vcpu halt_poll_ns. */
unsigned int halt_poll_ns_grow = 2;
module_param(halt_poll_ns_grow, uint, 0644);
EXPORT_SYMBOL_GPL(halt_poll_ns_grow);
/* The start value to grow halt_poll_ns from */
unsigned int halt_poll_ns_grow_start = 10000; /* 10us */
module_param(halt_poll_ns_grow_start, uint, 0644);
EXPORT_SYMBOL_GPL(halt_poll_ns_grow_start);
/* Default resets per-vcpu halt_poll_ns . */
unsigned int halt_poll_ns_shrink;
module_param(halt_poll_ns_shrink, uint, 0644);
EXPORT_SYMBOL_GPL(halt_poll_ns_shrink);
/*
* Ordering of locks:
*
* kvm->lock --> kvm->slots_lock --> kvm->irq_lock
*/
DEFINE_MUTEX(kvm_lock);
static DEFINE_RAW_SPINLOCK(kvm_count_lock);
LIST_HEAD(vm_list);
static cpumask_var_t cpus_hardware_enabled;
static int kvm_usage_count;
static atomic_t hardware_enable_failed;
static struct kmem_cache *kvm_vcpu_cache;
static __read_mostly struct preempt_ops kvm_preempt_ops;
static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_running_vcpu);
struct dentry *kvm_debugfs_dir;
EXPORT_SYMBOL_GPL(kvm_debugfs_dir);
static int kvm_debugfs_num_entries;
static const struct file_operations stat_fops_per_vm;
static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
unsigned long arg);
#ifdef CONFIG_KVM_COMPAT
static long kvm_vcpu_compat_ioctl(struct file *file, unsigned int ioctl,
unsigned long arg);
#define KVM_COMPAT(c) .compat_ioctl = (c)
#else
/*
* For architectures that don't implement a compat infrastructure,
* adopt a double line of defense:
* - Prevent a compat task from opening /dev/kvm
* - If the open has been done by a 64bit task, and the KVM fd
* passed to a compat task, let the ioctls fail.
*/
static long kvm_no_compat_ioctl(struct file *file, unsigned int ioctl,
unsigned long arg) { return -EINVAL; }
static int kvm_no_compat_open(struct inode *inode, struct file *file)
{
return is_compat_task() ? -ENODEV : 0;
}
#define KVM_COMPAT(c) .compat_ioctl = kvm_no_compat_ioctl, \
.open = kvm_no_compat_open
#endif
static int hardware_enable_all(void);
static void hardware_disable_all(void);
static void kvm_io_bus_destroy(struct kvm_io_bus *bus);
__visible bool kvm_rebooting;
EXPORT_SYMBOL_GPL(kvm_rebooting);
#define KVM_EVENT_CREATE_VM 0
#define KVM_EVENT_DESTROY_VM 1
static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm);
static unsigned long long kvm_createvm_count;
static unsigned long long kvm_active_vms;
__weak void kvm_arch_mmu_notifier_invalidate_range(struct kvm *kvm,
unsigned long start, unsigned long end)
{
}
bool kvm_is_zone_device_pfn(kvm_pfn_t pfn)
{
/*
* The metadata used by is_zone_device_page() to determine whether or
* not a page is ZONE_DEVICE is guaranteed to be valid if and only if
* the device has been pinned, e.g. by get_user_pages(). WARN if the
* page_count() is zero to help detect bad usage of this helper.
*/
if (!pfn_valid(pfn) || WARN_ON_ONCE(!page_count(pfn_to_page(pfn))))
return false;
return is_zone_device_page(pfn_to_page(pfn));
}
bool kvm_is_reserved_pfn(kvm_pfn_t pfn)
{
/*
* ZONE_DEVICE pages currently set PG_reserved, but from a refcounting
* perspective they are "normal" pages, albeit with slightly different
* usage rules.
*/
if (pfn_valid(pfn))
return PageReserved(pfn_to_page(pfn)) &&
!is_zero_pfn(pfn) &&
!kvm_is_zone_device_pfn(pfn);
return true;
}
bool kvm_is_transparent_hugepage(kvm_pfn_t pfn)
{
struct page *page = pfn_to_page(pfn);
if (!PageTransCompoundMap(page))
return false;
return is_transparent_hugepage(compound_head(page));
}
/*
* Switches to specified vcpu, until a matching vcpu_put()
*/
void vcpu_load(struct kvm_vcpu *vcpu)
{
int cpu = get_cpu();
__this_cpu_write(kvm_running_vcpu, vcpu);
preempt_notifier_register(&vcpu->preempt_notifier);
kvm_arch_vcpu_load(vcpu, cpu);
put_cpu();
}
EXPORT_SYMBOL_GPL(vcpu_load);
void vcpu_put(struct kvm_vcpu *vcpu)
{
preempt_disable();
kvm_arch_vcpu_put(vcpu);
preempt_notifier_unregister(&vcpu->preempt_notifier);
__this_cpu_write(kvm_running_vcpu, NULL);
preempt_enable();
}
EXPORT_SYMBOL_GPL(vcpu_put);
/* TODO: merge with kvm_arch_vcpu_should_kick */
static bool kvm_request_needs_ipi(struct kvm_vcpu *vcpu, unsigned req)
{
int mode = kvm_vcpu_exiting_guest_mode(vcpu);
/*
* We need to wait for the VCPU to reenable interrupts and get out of
* READING_SHADOW_PAGE_TABLES mode.
*/
if (req & KVM_REQUEST_WAIT)
return mode != OUTSIDE_GUEST_MODE;
/*
* Need to kick a running VCPU, but otherwise there is nothing to do.
*/
return mode == IN_GUEST_MODE;
}
static void ack_flush(void *_completed)
{
}
static inline bool kvm_kick_many_cpus(const struct cpumask *cpus, bool wait)
{
if (unlikely(!cpus))
cpus = cpu_online_mask;
if (cpumask_empty(cpus))
return false;
smp_call_function_many(cpus, ack_flush, NULL, wait);
return true;
}
bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
struct kvm_vcpu *except,
unsigned long *vcpu_bitmap, cpumask_var_t tmp)
{
int i, cpu, me;
struct kvm_vcpu *vcpu;
bool called;
me = get_cpu();
kvm_for_each_vcpu(i, vcpu, kvm) {
if ((vcpu_bitmap && !test_bit(i, vcpu_bitmap)) ||
vcpu == except)
continue;
kvm_make_request(req, vcpu);
cpu = vcpu->cpu;
if (!(req & KVM_REQUEST_NO_WAKEUP) && kvm_vcpu_wake_up(vcpu))
continue;
if (tmp != NULL && cpu != -1 && cpu != me &&
kvm_request_needs_ipi(vcpu, req))
__cpumask_set_cpu(cpu, tmp);
}
called = kvm_kick_many_cpus(tmp, !!(req & KVM_REQUEST_WAIT));
put_cpu();
return called;
}
bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req,
struct kvm_vcpu *except)
{
cpumask_var_t cpus;
bool called;
zalloc_cpumask_var(&cpus, GFP_ATOMIC);
called = kvm_make_vcpus_request_mask(kvm, req, except, NULL, cpus);
free_cpumask_var(cpus);
return called;
}
bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
{
return kvm_make_all_cpus_request_except(kvm, req, NULL);
}
#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);
}
#ifdef KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE
static inline void *mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache *mc,
gfp_t gfp_flags)
{
gfp_flags |= mc->gfp_zero;
if (mc->kmem_cache)
return kmem_cache_alloc(mc->kmem_cache, gfp_flags);
else
return (void *)__get_free_page(gfp_flags);
}
int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min)
{
void *obj;
if (mc->nobjs >= min)
return 0;
while (mc->nobjs < ARRAY_SIZE(mc->objects)) {
obj = mmu_memory_cache_alloc_obj(mc, GFP_KERNEL_ACCOUNT);
if (!obj)
return mc->nobjs >= min ? 0 : -ENOMEM;
mc->objects[mc->nobjs++] = obj;
}
return 0;
}
int kvm_mmu_memory_cache_nr_free_objects(struct kvm_mmu_memory_cache *mc)
{
return mc->nobjs;
}
void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
{
while (mc->nobjs) {
if (mc->kmem_cache)
kmem_cache_free(mc->kmem_cache, mc->objects[--mc->nobjs]);
else
free_page((unsigned long)mc->objects[--mc->nobjs]);
}
}
void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
{
void *p;
if (WARN_ON(!mc->nobjs))
p = mmu_memory_cache_alloc_obj(mc, GFP_ATOMIC | __GFP_ACCOUNT);
else
p = mc->objects[--mc->nobjs];
BUG_ON(!p);
return p;
}
#endif
static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
{
mutex_init(&vcpu->mutex);
vcpu->cpu = -1;
vcpu->kvm = kvm;
vcpu->vcpu_id = id;
vcpu->pid = NULL;
rcuwait_init(&vcpu->wait);
kvm_async_pf_vcpu_init(vcpu);
vcpu->pre_pcpu = -1;
INIT_LIST_HEAD(&vcpu->blocked_vcpu_list);
kvm_vcpu_set_in_spin_loop(vcpu, false);
kvm_vcpu_set_dy_eligible(vcpu, false);
vcpu->preempted = false;
vcpu->ready = false;
preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops);
}
void kvm_vcpu_destroy(struct kvm_vcpu *vcpu)
{
kvm_dirty_ring_free(&vcpu->dirty_ring);
kvm_arch_vcpu_destroy(vcpu);
/*
* No need for rcu_read_lock as VCPU_RUN is the only place that changes
* the vcpu->pid pointer, and at destruction time all file descriptors
* are already gone.
*/
put_pid(rcu_dereference_protected(vcpu->pid, 1));
free_page((unsigned long)vcpu->run);
kmem_cache_free(kvm_vcpu_cache, vcpu);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_destroy);
#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn)
{
return container_of(mn, struct kvm, mmu_notifier);
}
static void kvm_mmu_notifier_invalidate_range(struct mmu_notifier *mn,
struct mm_struct *mm,
unsigned long start, unsigned long end)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
int idx;
idx = srcu_read_lock(&kvm->srcu);
kvm_arch_mmu_notifier_invalidate_range(kvm, start, end);
srcu_read_unlock(&kvm->srcu, idx);
}
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);
KVM_MMU_LOCK(kvm);
kvm->mmu_notifier_seq++;
if (kvm_set_spte_hva(kvm, address, pte))
kvm_flush_remote_tlbs(kvm);
KVM_MMU_UNLOCK(kvm);
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);
KVM_MMU_LOCK(kvm);
/*
* The count increase must become visible at unlock time as no
* spte can be established without taking the mmu_lock and
* count is also read inside the mmu_lock critical section.
*/
kvm->mmu_notifier_count++;
if (likely(kvm->mmu_notifier_count == 1)) {
kvm->mmu_notifier_range_start = range->start;
kvm->mmu_notifier_range_end = range->end;
} else {
/*
* Fully tracking multiple concurrent ranges has dimishing
* returns. Keep things simple and just find the minimal range
* which includes the current and new ranges. As there won't be
* enough information to subtract a range after its invalidate
* completes, any ranges invalidated concurrently will
* accumulate and persist until all outstanding invalidates
* complete.
*/
kvm->mmu_notifier_range_start =
min(kvm->mmu_notifier_range_start, range->start);
kvm->mmu_notifier_range_end =
max(kvm->mmu_notifier_range_end, range->end);
}
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);
KVM_MMU_UNLOCK(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);
KVM_MMU_LOCK(kvm);
/*
* 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--;
KVM_MMU_UNLOCK(kvm);
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);
KVM_MMU_LOCK(kvm);
young = kvm_age_hva(kvm, start, end);
if (young)
kvm_flush_remote_tlbs(kvm);
KVM_MMU_UNLOCK(kvm);
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);
KVM_MMU_LOCK(kvm);
/*
* 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);
KVM_MMU_UNLOCK(kvm);
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);
KVM_MMU_LOCK(kvm);
young = kvm_test_age_hva(kvm, address);
KVM_MMU_UNLOCK(kvm);
srcu_read_unlock(&kvm->srcu, idx);
return young;
}
static void kvm_mmu_notifier_release(struct mmu_notifier *mn,
struct mm_struct *mm)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
int idx;
idx = srcu_read_lock(&kvm->srcu);
kvm_arch_flush_shadow_all(kvm);
srcu_read_unlock(&kvm->srcu, idx);
}
static const struct mmu_notifier_ops kvm_mmu_notifier_ops = {
.invalidate_range = 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)
{
char dir_name[ITOA_MAX_LEN * 2];
struct kvm_stat_data *stat_data;
struct kvm_stats_debugfs_item *p;
if (!debugfs_initialized())
return 0;
snprintf(dir_name, sizeof(dir_name), "%d-%d", task_pid_nr(current), fd);
kvm->debugfs_dentry = debugfs_create_dir(dir_name, kvm_debugfs_dir);
kvm->debugfs_stat_data = kcalloc(kvm_debugfs_num_entries,
sizeof(*kvm->debugfs_stat_data),
GFP_KERNEL_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);
KVM_MMU_LOCK_INIT(kvm);
mmgrab(current->mm);
kvm->mm = current->mm;
kvm_eventfd_init(kvm);
mutex_init(&kvm->lock);
mutex_init(&kvm->irq_lock);
mutex_init(&kvm->slots_lock);
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();
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_arch_flush_shadow_all(kvm);
#endif
kvm_arch_destroy_vm(kvm);
kvm_destroy_devices(kvm);
for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++)
kvm_free_memslots(kvm, __kvm_memslots(kvm, i));
cleanup_srcu_struct(&kvm->irq_srcu);
cleanup_srcu_struct(&kvm->srcu);
kvm_arch_free_vm(kvm);
preempt_notifier_dec();
hardware_disable_all();
mmdrop(mm);
}
void kvm_get_kvm(struct kvm *kvm)
{
refcount_inc(&kvm->users_count);
}
EXPORT_SYMBOL_GPL(kvm_get_kvm);
void kvm_put_kvm(struct kvm *kvm)
{
if (refcount_dec_and_test(&kvm->users_count))
kvm_destroy_vm(kvm);
}
EXPORT_SYMBOL_GPL(kvm_put_kvm);
/*
* Used to put a reference that was taken on behalf of an object associated
* with a user-visible file descriptor, e.g. a vcpu or device, if installation
* of the new file descriptor fails and the reference cannot be transferred to
* its final owner. In such cases, the caller is still actively using @kvm and
* will fail miserably if the refcount unexpectedly hits zero.
*/
void kvm_put_kvm_no_destroy(struct kvm *kvm)
{
WARN_ON(refcount_dec_and_test(&kvm->users_count));
}
EXPORT_SYMBOL_GPL(kvm_put_kvm_no_destroy);
static int kvm_vm_release(struct inode *inode, struct file *filp)
{
struct kvm *kvm = filp->private_data;
kvm_irqfd_release(kvm);
kvm_put_kvm(kvm);
return 0;
}
/*
* Allocation size is twice as large as the actual dirty bitmap size.
* See kvm_vm_ioctl_get_dirty_log() why this is needed.
*/
static int kvm_alloc_dirty_bitmap(struct kvm_memory_slot *memslot)
{
unsigned long dirty_bytes = 2 * kvm_dirty_bitmap_bytes(memslot);
memslot->dirty_bitmap = kvzalloc(dirty_bytes, GFP_KERNEL_ACCOUNT);
if (!memslot->dirty_bitmap)
return -ENOMEM;
return 0;
}
/*
* Delete a memslot by decrementing the number of used slots and shifting all
* other entries in the array forward one spot.
*/
static inline void kvm_memslot_delete(struct kvm_memslots *slots,
struct kvm_memory_slot *memslot)
{
struct kvm_memory_slot *mslots = slots->memslots;
int i;
if (WARN_ON(slots->id_to_index[memslot->id] == -1))
return;
slots->used_slots--;
if (atomic_read(&slots->lru_slot) >= slots->used_slots)
atomic_set(&slots->lru_slot, 0);
for (i = slots->id_to_index[memslot->id]; i < slots->used_slots; i++) {
mslots[i] = mslots[i + 1];
slots->id_to_index[mslots[i].id] = i;
}
mslots[i] = *memslot;
slots->id_to_index[memslot->id] = -1;
}
/*
* "Insert" a new memslot by incrementing the number of used slots. Returns
* the new slot's initial index into the memslots array.
*/
static inline int kvm_memslot_insert_back(struct kvm_memslots *slots)
{
return slots->used_slots++;
}
/*
* Move a changed memslot backwards in the array by shifting existing slots
* with a higher GFN toward the front of the array. Note, the changed memslot
* itself is not preserved in the array, i.e. not swapped at this time, only
* its new index into the array is tracked. Returns the changed memslot's
* current index into the memslots array.
*/
static inline int kvm_memslot_move_backward(struct kvm_memslots *slots,
struct kvm_memory_slot *memslot)
{
struct kvm_memory_slot *mslots = slots->memslots;
int i;
if (WARN_ON_ONCE(slots->id_to_index[memslot->id] == -1) ||
WARN_ON_ONCE(!slots->used_slots))
return -1;
/*
* Move the target memslot backward in the array by shifting existing
* memslots with a higher GFN (than the target memslot) towards the
* front of the array.
*/
for (i = slots->id_to_index[memslot->id]; i < slots->used_slots - 1; i++) {
if (memslot->base_gfn > mslots[i + 1].base_gfn)
break;
WARN_ON_ONCE(memslot->base_gfn == mslots[i + 1].base_gfn);
/* Shift the next memslot forward one and update its index. */
mslots[i] = mslots[i + 1];
slots->id_to_index[mslots[i].id] = i;
}
return i;
}
/*
* Move a changed memslot forwards in the array by shifting existing slots with
* a lower GFN toward the back of the array. Note, the changed memslot itself
* is not preserved in the array, i.e. not swapped at this time, only its new
* index into the array is tracked. Returns the changed memslot's final index
* into the memslots array.
*/
static inline int kvm_memslot_move_forward(struct kvm_memslots *slots,
struct kvm_memory_slot *memslot,
int start)
{
struct kvm_memory_slot *mslots = slots->memslots;
int i;
for (i = start; i > 0; i--) {
if (memslot->base_gfn < mslots[i - 1].base_gfn)
break;
WARN_ON_ONCE(memslot->base_gfn == mslots[i - 1].base_gfn);
/* Shift the next memslot back one and update its index. */
mslots[i] = mslots[i - 1];
slots->id_to_index[mslots[i].id] = i;
}
return i;
}
/*
* Re-sort memslots based on their GFN to account for an added, deleted, or
* moved memslot. Sorting memslots by GFN allows using a binary search during
* memslot lookup.
*
* IMPORTANT: Slots are sorted from highest GFN to lowest GFN! I.e. the entry
* at memslots[0] has the highest GFN.
*
* The sorting algorithm takes advantage of having initially sorted memslots
* and knowing the position of the changed memslot. Sorting is also optimized
* by not swapping the updated memslot and instead only shifting other memslots
* and tracking the new index for the update memslot. Only once its final
* index is known is the updated memslot copied into its position in the array.
*
* - When deleting a memslot, the deleted memslot simply needs to be moved to
* the end of the array.
*
* - When creating a memslot, the algorithm "inserts" the new memslot at the
* end of the array and then it forward to its correct location.
*
* - When moving a memslot, the algorithm first moves the updated memslot
* backward to handle the scenario where the memslot's GFN was changed to a
* lower value. update_memslots() then falls through and runs the same flow
* as creating a memslot to move the memslot forward to handle the scenario
* where its GFN was changed to a higher value.
*
* Note, slots are sorted from highest->lowest instead of lowest->highest for
* historical reasons. Originally, invalid memslots where denoted by having
* GFN=0, thus sorting from highest->lowest naturally sorted invalid memslots
* to the end of the array. The current algorithm uses dedicated logic to
* delete a memslot and thus does not rely on invalid memslots having GFN=0.
*
* The other historical motiviation for highest->lowest was to improve the
* performance of memslot lookup. KVM originally used a linear search starting
* at memslots[0]. On x86, the largest memslot usually has one of the highest,
* if not *the* highest, GFN, as the bulk of the guest's RAM is located in a
* single memslot above the 4gb boundary. As the largest memslot is also the
* most likely to be referenced, sorting it to the front of the array was
* advantageous. The current binary search starts from the middle of the array
* and uses an LRU pointer to improve performance for all memslots and GFNs.
*/
static void update_memslots(struct kvm_memslots *slots,
struct kvm_memory_slot *memslot,
enum kvm_mr_change change)
{
int i;
if (change == KVM_MR_DELETE) {
kvm_memslot_delete(slots, memslot);
} else {
if (change == KVM_MR_CREATE)
i = kvm_memslot_insert_back(slots);
else
i = kvm_memslot_move_backward(slots, memslot);
i = kvm_memslot_move_forward(slots, memslot, i);
/*
* Copy the memslot to its new position in memslots and update
* its index accordingly.
*/
slots->memslots[i] = *memslot;
slots->id_to_index[memslot->id] = i;
}
}
static int check_memory_region_flags(const struct kvm_userspace_memory_region *mem)
{
u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES;
#ifdef __KVM_HAVE_READONLY_MEM
valid_flags |= KVM_MEM_READONLY;
#endif
if (mem->flags & ~valid_flags)
return -EINVAL;
return 0;
}
static struct kvm_memslots *install_new_memslots(struct kvm *kvm,
int as_id, struct kvm_memslots *slots)
{
struct kvm_memslots *old_memslots = __kvm_memslots(kvm, as_id);
u64 gen = old_memslots->generation;
WARN_ON(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS);
slots->generation = gen | KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS;
rcu_assign_pointer(kvm->memslots[as_id], slots);
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);
}
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))
return -EINVAL;
if (mem->guest_phys_addr & (PAGE_SIZE - 1))
return -EINVAL;
/* We can read the guest memory with __xxx_user() later on. */
if ((mem->userspace_addr & (PAGE_SIZE - 1)) ||
(mem->userspace_addr != untagged_addr(mem->userspace_addr)) ||
!access_ok((void __user *)(unsigned long)mem->userspace_addr,
mem->memory_size))
return -EINVAL;
if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_MEM_SLOTS_NUM)
return -EINVAL;
if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr)
return -EINVAL;
/*
* Make a full copy of the old memslot, the pointer will become stale
* when the memslots are re-sorted by update_memslots(), and the old
* memslot needs to be referenced after calling update_memslots(), e.g.
* to free its resources and for arch specific behavior.
*/
tmp = id_to_memslot(__kvm_memslots(kvm, as_id), id);
if (tmp) {
old = *tmp;
tmp = NULL;
} else {
memset(&old, 0, sizeof(old));
old.id = id;
}
if (!mem->memory_size)
return kvm_delete_memslot(kvm, mem, &old, as_id);
new.as_id = as_id;
new.id = id;
new.base_gfn = mem->guest_phys_addr >> PAGE_SHIFT;
new.npages = mem->memory_size >> PAGE_SHIFT;
new.flags = mem->flags;
new.userspace_addr = mem->userspace_addr;
if (new.npages > KVM_MEM_MAX_NR_PAGES)
return -EINVAL;
if (!old.npages) {
change = KVM_MR_CREATE;
new.dirty_bitmap = NULL;
memset(&new.arch, 0, sizeof(new.arch));
} else { /* Modify an existing slot. */
if ((new.userspace_addr != old.userspace_addr) ||
(new.npages != old.npages) ||
((new.flags ^ old.flags) & KVM_MEM_READONLY))
return -EINVAL;
if (new.base_gfn != old.base_gfn)
change = KVM_MR_MOVE;
else if (new.flags != old.flags)
change = KVM_MR_FLAGS_ONLY;
else /* Nothing to change. */
return 0;
/* Copy dirty_bitmap and arch from the current memslot. */
new.dirty_bitmap = old.dirty_bitmap;
memcpy(&new.arch, &old.arch, sizeof(new.arch));
}
if ((change == KVM_MR_CREATE) || (change == KVM_MR_MOVE)) {
/* Check for overlaps */
kvm_for_each_memslot(tmp, __kvm_memslots(kvm, as_id)) {
if (tmp->id == id)
continue;
if (!((new.base_gfn + new.npages <= tmp->base_gfn) ||
(new.base_gfn >= tmp->base_gfn + tmp->npages)))
return -EEXIST;
}
}
/* Allocate/free page dirty bitmap as needed */
if (!(new.flags & KVM_MEM_LOG_DIRTY_PAGES))
new.dirty_bitmap = NULL;
else if (!new.dirty_bitmap && !kvm->dirty_ring_size) {
r = kvm_alloc_dirty_bitmap(&new);
if (r)
return r;
if (kvm_dirty_log_manual_protect_and_init_set(kvm))
bitmap_set(new.dirty_bitmap, 0, new.npages);
}
r = kvm_set_memslot(kvm, mem, &old, &new, as_id, change);
if (r)
goto out_bitmap;
if (old.dirty_bitmap && !new.dirty_bitmap)
kvm_destroy_dirty_bitmap(&old);
return 0;
out_bitmap:
if (new.dirty_bitmap && !old.dirty_bitmap)
kvm_destroy_dirty_bitmap(&new);
return r;
}
EXPORT_SYMBOL_GPL(__kvm_set_memory_region);
int kvm_set_memory_region(struct kvm *kvm,
const struct kvm_userspace_memory_region *mem)
{
int r;
mutex_lock(&kvm->slots_lock);
r = __kvm_set_memory_region(kvm, mem);
mutex_unlock(&kvm->slots_lock);
return r;
}
EXPORT_SYMBOL_GPL(kvm_set_memory_region);
static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
struct kvm_userspace_memory_region *mem)
{
if ((u16)mem->slot >= KVM_USER_MEM_SLOTS)
return -EINVAL;
return kvm_set_memory_region(kvm, mem);
}
#ifndef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
/**
* kvm_get_dirty_log - get a snapshot of dirty pages
* @kvm: pointer to kvm instance
* @log: slot id and address to which we copy the log
* @is_dirty: set to '1' if any dirty pages were found
* @memslot: set to the associated memslot, always valid on success
*/
int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log,
int *is_dirty, struct kvm_memory_slot **memslot)
{
struct kvm_memslots *slots;
int i, as_id, id;
unsigned long n;
unsigned long any = 0;
/* Dirty ring tracking is exclusive to dirty log tracking */
if (kvm->dirty_ring_size)
return -ENXIO;
*memslot = NULL;
*is_dirty = 0;
as_id = log->slot >> 16;
id = (u16)log->slot;
if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS)
return -EINVAL;
slots = __kvm_memslots(kvm, as_id);
*memslot = id_to_memslot(slots, id);
if (!(*memslot) || !(*memslot)->dirty_bitmap)
return -ENOENT;
kvm_arch_sync_dirty_log(kvm, *memslot);
n = kvm_dirty_bitmap_bytes(*memslot);
for (i = 0; !any && i < n/sizeof(long); ++i)
any = (*memslot)->dirty_bitmap[i];
if (copy_to_user(log->dirty_bitmap, (*memslot)->dirty_bitmap, n))
return -EFAULT;
if (any)
*is_dirty = 1;
return 0;
}
EXPORT_SYMBOL_GPL(kvm_get_dirty_log);
#else /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
/**
* kvm_get_dirty_log_protect - get a snapshot of dirty pages
* and reenable dirty page tracking for the corresponding pages.
* @kvm: pointer to kvm instance
* @log: slot id and address to which we copy the log
*
* We need to keep it in mind that VCPU threads can write to the bitmap
* concurrently. So, to avoid losing track of dirty pages we keep the
* following order:
*
* 1. Take a snapshot of the bit and clear it if needed.
* 2. Write protect the corresponding page.
* 3. Copy the snapshot to the userspace.
* 4. Upon return caller flushes TLB's if needed.
*
* Between 2 and 4, the guest may write to the page using the remaining TLB
* entry. This is not a problem because the page is reported dirty using
* the snapshot taken before and step 4 ensures that writes done after
* exiting to userspace will be logged for the next call.
*
*/
static int kvm_get_dirty_log_protect(struct kvm *kvm, struct kvm_dirty_log *log)
{
struct kvm_memslots *slots;
struct kvm_memory_slot *memslot;
int i, as_id, id;
unsigned long n;
unsigned long *dirty_bitmap;
unsigned long *dirty_bitmap_buffer;
bool flush;
/* Dirty ring tracking is exclusive to dirty log tracking */
if (kvm->dirty_ring_size)
return -ENXIO;
as_id = log->slot >> 16;
id = (u16)log->slot;
if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS)
return -EINVAL;
slots = __kvm_memslots(kvm, as_id);
memslot = id_to_memslot(slots, id);
if (!memslot || !memslot->dirty_bitmap)
return -ENOENT;
dirty_bitmap = memslot->dirty_bitmap;
kvm_arch_sync_dirty_log(kvm, memslot);
n = kvm_dirty_bitmap_bytes(memslot);
flush = false;
if (kvm->manual_dirty_log_protect) {
/*
* Unlike kvm_get_dirty_log, we always return false in *flush,
* because no flush is needed until KVM_CLEAR_DIRTY_LOG. There
* is some code duplication between this function and
* kvm_get_dirty_log, but hopefully all architecture
* transition to kvm_get_dirty_log_protect and kvm_get_dirty_log
* can be eliminated.
*/
dirty_bitmap_buffer = dirty_bitmap;
} else {
dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot);
memset(dirty_bitmap_buffer, 0, n);
KVM_MMU_LOCK(kvm);
for (i = 0; i < n / sizeof(long); i++) {
unsigned long mask;
gfn_t offset;
if (!dirty_bitmap[i])
continue;
flush = true;
mask = xchg(&dirty_bitmap[i], 0);
dirty_bitmap_buffer[i] = mask;
offset = i * BITS_PER_LONG;
kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot,
offset, mask);
}
KVM_MMU_UNLOCK(kvm);
}
if (flush)
kvm_arch_flush_remote_tlbs_memslot(kvm, memslot);
if (copy_to_user(log->dirty_bitmap, dirty_bitmap_buffer, n))
return -EFAULT;
return 0;
}
/**
* kvm_vm_ioctl_get_dirty_log - get and clear the log of dirty pages in a slot
* @kvm: kvm instance
* @log: slot id and address to which we copy the log
*
* Steps 1-4 below provide general overview of dirty page logging. See
* kvm_get_dirty_log_protect() function description for additional details.
*
* We call kvm_get_dirty_log_protect() to handle steps 1-3, upon return we
* always flush the TLB (step 4) even if previous step failed and the dirty
* bitmap may be corrupt. Regardless of previous outcome the KVM logging API
* does not preclude user space subsequent dirty log read. Flushing TLB ensures
* writes will be marked dirty for next log read.
*
* 1. Take a snapshot of the bit and clear it if needed.
* 2. Write protect the corresponding page.
* 3. Copy the snapshot to the userspace.
* 4. Flush TLB's if needed.
*/
static int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
struct kvm_dirty_log *log)
{
int r;
mutex_lock(&kvm->slots_lock);
r = kvm_get_dirty_log_protect(kvm, log);
mutex_unlock(&kvm->slots_lock);
return r;
}
/**
* kvm_clear_dirty_log_protect - clear dirty bits in the bitmap
* and reenable dirty page tracking for the corresponding pages.
* @kvm: pointer to kvm instance
* @log: slot id and address from which to fetch the bitmap of dirty pages
*/
static int kvm_clear_dirty_log_protect(struct kvm *kvm,
struct kvm_clear_dirty_log *log)
{
struct kvm_memslots *slots;
struct kvm_memory_slot *memslot;
int as_id, id;
gfn_t offset;
unsigned long i, n;
unsigned long *dirty_bitmap;
unsigned long *dirty_bitmap_buffer;
bool flush;
/* Dirty ring tracking is exclusive to dirty log tracking */
if (kvm->dirty_ring_size)
return -ENXIO;
as_id = log->slot >> 16;
id = (u16)log->slot;
if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS)
return -EINVAL;
if (log->first_page & 63)
return -EINVAL;
slots = __kvm_memslots(kvm, as_id);
memslot = id_to_memslot(slots, id);
if (!memslot || !memslot->dirty_bitmap)
return -ENOENT;
dirty_bitmap = memslot->dirty_bitmap;
n = ALIGN(log->num_pages, BITS_PER_LONG) / 8;
if (log->first_page > memslot->npages ||
log->num_pages > memslot->npages - log->first_page ||
(log->num_pages < memslot->npages - log->first_page && (log->num_pages & 63)))
return -EINVAL;
kvm_arch_sync_dirty_log(kvm, memslot);
flush = false;
dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot);
if (copy_from_user(dirty_bitmap_buffer, log->dirty_bitmap, n))
return -EFAULT;
KVM_MMU_LOCK(kvm);
for (offset = log->first_page, i = offset / BITS_PER_LONG,
n = DIV_ROUND_UP(log->num_pages, BITS_PER_LONG); n--;
i++, offset += BITS_PER_LONG) {
unsigned long mask = *dirty_bitmap_buffer++;
atomic_long_t *p = (atomic_long_t *) &dirty_bitmap[i];
if (!mask)
continue;
mask &= atomic_long_fetch_andnot(mask, p);
/*
* mask contains the bits that really have been cleared. This
* never includes any bits beyond the length of the memslot (if
* the length is not aligned to 64 pages), therefore it is not
* a problem if userspace sets them in log->dirty_bitmap.
*/
if (mask) {
flush = true;
kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot,
offset, mask);
}
}
KVM_MMU_UNLOCK(kvm);
if (flush)
kvm_arch_flush_remote_tlbs_memslot(kvm, memslot);
return 0;
}
static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
struct kvm_clear_dirty_log *log)
{
int r;
mutex_lock(&kvm->slots_lock);
r = kvm_clear_dirty_log_protect(kvm, log);
mutex_unlock(&kvm->slots_lock);
return r;
}
#endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
{
return __gfn_to_memslot(kvm_memslots(kvm), gfn);
}
EXPORT_SYMBOL_GPL(gfn_to_memslot);
struct kvm_memory_slot *kvm_vcpu_gfn_to_memslot(struct kvm_vcpu *vcpu, gfn_t gfn)
{
return __gfn_to_memslot(kvm_vcpu_memslots(vcpu), gfn);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_memslot);
bool kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
{
struct kvm_memory_slot *memslot = gfn_to_memslot(kvm, gfn);
return kvm_is_visible_memslot(memslot);
}
EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);
bool kvm_vcpu_is_visible_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
{
struct kvm_memory_slot *memslot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
return kvm_is_visible_memslot(memslot);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_is_visible_gfn);
unsigned long kvm_host_page_size(struct kvm_vcpu *vcpu, gfn_t gfn)
{
struct vm_area_struct *vma;
unsigned long addr, size;
size = PAGE_SIZE;
addr = kvm_vcpu_gfn_to_hva_prot(vcpu, gfn, NULL);
if (kvm_is_error_hva(addr))
return PAGE_SIZE;
mmap_read_lock(current->mm);
vma = find_vma(current->mm, addr);
if (!vma)
goto out;
size = vma_kernel_pagesize(vma);
out:
mmap_read_unlock(current->mm);
return size;
}
static bool memslot_is_readonly(struct kvm_memory_slot *slot)
{
return slot->flags & KVM_MEM_READONLY;
}
static unsigned long __gfn_to_hva_many(struct kvm_memory_slot *slot, gfn_t gfn,
gfn_t *nr_pages, bool write)
{
if (!slot || slot->flags & KVM_MEMSLOT_INVALID)
return KVM_HVA_ERR_BAD;
if (memslot_is_readonly(slot) && write)
return KVM_HVA_ERR_RO_BAD;
if (nr_pages)
*nr_pages = slot->npages - (gfn - slot->base_gfn);
return __gfn_to_hva_memslot(slot, gfn);
}
static unsigned long gfn_to_hva_many(struct kvm_memory_slot *slot, gfn_t gfn,
gfn_t *nr_pages)
{
return __gfn_to_hva_many(slot, gfn, nr_pages, true);
}
unsigned long gfn_to_hva_memslot(struct kvm_memory_slot *slot,
gfn_t gfn)
{
return gfn_to_hva_many(slot, gfn, NULL);
}
EXPORT_SYMBOL_GPL(gfn_to_hva_memslot);
unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
{
return gfn_to_hva_many(gfn_to_memslot(kvm, gfn), gfn, NULL);
}
EXPORT_SYMBOL_GPL(gfn_to_hva);
unsigned long kvm_vcpu_gfn_to_hva(struct kvm_vcpu *vcpu, gfn_t gfn)
{
return gfn_to_hva_many(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn, NULL);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_hva);
/*
* Return the hva of a @gfn and the R/W attribute if possible.
*
* @slot: the kvm_memory_slot which contains @gfn
* @gfn: the gfn to be translated
* @writable: used to return the read/write attribute of the @slot if the hva
* is valid and @writable is not NULL
*/
unsigned long gfn_to_hva_memslot_prot(struct kvm_memory_slot *slot,
gfn_t gfn, bool *writable)
{
unsigned long hva = __gfn_to_hva_many(slot, gfn, NULL, false);
if (!kvm_is_error_hva(hva) && writable)
*writable = !memslot_is_readonly(slot);
return hva;
}
unsigned long gfn_to_hva_prot(struct kvm *kvm, gfn_t gfn, bool *writable)
{
struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
return gfn_to_hva_memslot_prot(slot, gfn, writable);
}
unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *writable)
{
struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
return gfn_to_hva_memslot_prot(slot, gfn, writable);
}
static inline int check_user_page_hwpoison(unsigned long addr)
{
int rc, flags = FOLL_HWPOISON | FOLL_WRITE;
rc = get_user_pages(addr, 1, flags, NULL, NULL);
return rc == -EHWPOISON;
}
/*
* The fast path to get the writable pfn which will be stored in @pfn,
* true indicates success, otherwise false is returned. It's also the
* only part that runs if we can in atomic context.
*/
static bool hva_to_pfn_fast(unsigned long addr, bool write_fault,
bool *writable, kvm_pfn_t *pfn)
{
struct page *page[1];
/*
* Fast pin a writable pfn only if it is a write fault request
* or the caller allows to map a writable pfn for a read fault
* request.
*/
if (!(write_fault || writable))
return false;
if (get_user_page_fast_only(addr, FOLL_WRITE, page)) {
*pfn = page_to_pfn(page[0]);
if (writable)
*writable = true;
return true;
}
return false;
}
/*
* The slow path to get the pfn of the specified host virtual address,
* 1 indicates success, -errno is returned if error is detected.
*/
static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault,
bool *writable, kvm_pfn_t *pfn)
{
unsigned int flags = FOLL_HWPOISON;
struct page *page;
int npages = 0;
might_sleep();
if (writable)
*writable = write_fault;
if (write_fault)
flags |= FOLL_WRITE;
if (async)
flags |= FOLL_NOWAIT;
npages = get_user_pages_unlocked(addr, 1, &page, flags);
if (npages != 1)
return npages;
/* map read fault as writable if possible */
if (unlikely(!write_fault) && writable) {
struct page *wpage;
if (get_user_page_fast_only(addr, FOLL_WRITE, &wpage)) {
*writable = true;
put_page(page);
page = wpage;
}
}
*pfn = page_to_pfn(page);
return npages;
}
static bool vma_is_valid(struct vm_area_struct *vma, bool write_fault)
{
if (unlikely(!(vma->vm_flags & VM_READ)))
return false;
if (write_fault && (unlikely(!(vma->vm_flags & VM_WRITE))))
return false;
return true;
}
static int 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.
*/
kvm_get_pfn(pfn);
out:
pte_unmap_unlock(ptep, ptl);
*p_pfn = pfn;
return 0;
}
/*
* Pin guest page in memory and return its pfn.
* @addr: host virtual address which maps memory to the guest
* @atomic: whether this function can sleep
* @async: whether this function need to wait IO complete if the
* host page is not in the memory
* @write_fault: whether we should get a writable host page
* @writable: whether it allows to map a writable host page for !@write_fault
*
* The function will map a writable host page for these two cases:
* 1): @write_fault = true
* 2): @write_fault = false && @writable, @writable will tell the caller
* whether the mapping is writable.
*/
static kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
bool write_fault, bool *writable)
{
struct vm_area_struct *vma;
kvm_pfn_t pfn = 0;
int npages, r;
/* we can do it either atomically or asynchronously, not both */
BUG_ON(atomic && async);
if (hva_to_pfn_fast(addr, write_fault, writable, &pfn))
return pfn;
if (atomic)
return KVM_PFN_ERR_FAULT;
npages = hva_to_pfn_slow(addr, async, write_fault, writable, &pfn);
if (npages == 1)
return pfn;
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, hva_t *hva)
{
unsigned long addr = __gfn_to_hva_many(slot, gfn, NULL, write_fault);
if (hva)
*hva = addr;
if (addr == KVM_HVA_ERR_RO_BAD) {
if (writable)
*writable = false;
return KVM_PFN_ERR_RO_FAULT;
}
if (kvm_is_error_hva(addr)) {
if (writable)
*writable = false;
return KVM_PFN_NOSLOT;
}
/* Do not map writable pfn in the readonly memslot. */
if (writable && memslot_is_readonly(slot)) {
*writable = false;
writable = NULL;
}
return hva_to_pfn(addr, atomic, async, write_fault,
writable);
}
EXPORT_SYMBOL_GPL(__gfn_to_pfn_memslot);
kvm_pfn_t gfn_to_pfn_prot(struct kvm *kvm, gfn_t gfn, bool write_fault,
bool *writable)
{
return __gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn, false, NULL,
write_fault, writable, NULL);
}
EXPORT_SYMBOL_GPL(gfn_to_pfn_prot);
kvm_pfn_t gfn_to_pfn_memslot(struct kvm_memory_slot *slot, gfn_t gfn)
{
return __gfn_to_pfn_memslot(slot, gfn, false, NULL, true, NULL, NULL);
}
EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot);
kvm_pfn_t gfn_to_pfn_memslot_atomic(struct kvm_memory_slot *slot, gfn_t gfn)
{
return __gfn_to_pfn_memslot(slot, gfn, true, NULL, true, NULL, NULL);
}
EXPORT_SYMBOL_GPL(gfn_to_pfn_memslot_atomic);
kvm_pfn_t kvm_vcpu_gfn_to_pfn_atomic(struct kvm_vcpu *vcpu, gfn_t gfn)
{
return gfn_to_pfn_memslot_atomic(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_pfn_atomic);
kvm_pfn_t gfn_to_pfn(struct kvm *kvm, gfn_t gfn)
{
return gfn_to_pfn_memslot(gfn_to_memslot(kvm, gfn), gfn);
}
EXPORT_SYMBOL_GPL(gfn_to_pfn);
kvm_pfn_t kvm_vcpu_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn)
{
return gfn_to_pfn_memslot(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_pfn);
int gfn_to_page_many_atomic(struct kvm_memory_slot *slot, gfn_t gfn,
struct page **pages, int nr_pages)
{
unsigned long addr;
gfn_t entry = 0;
addr = gfn_to_hva_many(slot, gfn, &entry);
if (kvm_is_error_hva(addr))
return -1;
if (entry < nr_pages)
return 0;
return get_user_pages_fast_only(addr, nr_pages, FOLL_WRITE, pages);
}
EXPORT_SYMBOL_GPL(gfn_to_page_many_atomic);
static struct page *kvm_pfn_to_page(kvm_pfn_t pfn)
{
if (is_error_noslot_pfn(pfn))
return KVM_ERR_PTR_BAD_PAGE;
if (kvm_is_reserved_pfn(pfn)) {
WARN_ON(1);
return KVM_ERR_PTR_BAD_PAGE;
}
return pfn_to_page(pfn);
}
struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
{
kvm_pfn_t pfn;
pfn = gfn_to_pfn(kvm, gfn);
return kvm_pfn_to_page(pfn);
}
EXPORT_SYMBOL_GPL(gfn_to_page);
void kvm_release_pfn(kvm_pfn_t pfn, bool dirty, struct gfn_to_pfn_cache *cache)
{
if (pfn == 0)
return;
if (cache)
cache->pfn = cache->gfn = 0;
if (dirty)
kvm_release_pfn_dirty(pfn);
else
kvm_release_pfn_clean(pfn);
}
static void kvm_cache_gfn_to_pfn(struct kvm_memory_slot *slot, gfn_t gfn,
struct gfn_to_pfn_cache *cache, u64 gen)
{
kvm_release_pfn(cache->pfn, cache->dirty, cache);
cache->pfn = gfn_to_pfn_memslot(slot, gfn);
cache->gfn = gfn;
cache->dirty = false;
cache->generation = gen;
}
static int __kvm_map_gfn(struct kvm_memslots *slots, gfn_t gfn,
struct kvm_host_map *map,
struct gfn_to_pfn_cache *cache,
bool atomic)
{
kvm_pfn_t pfn;
void *hva = NULL;
struct page *page = KVM_UNMAPPED_PAGE;
struct kvm_memory_slot *slot = __gfn_to_memslot(slots, gfn);
u64 gen = slots->generation;
if (!map)
return -EINVAL;
if (cache) {
if (!cache->pfn || cache->gfn != gfn ||
cache->generation != gen) {
if (atomic)
return -EAGAIN;
kvm_cache_gfn_to_pfn(slot, gfn, cache, gen);
}
pfn = cache->pfn;
} else {
if (atomic)
return -EAGAIN;
pfn = gfn_to_pfn_memslot(slot, gfn);
}
if (is_error_noslot_pfn(pfn))
return -EINVAL;
if (pfn_valid(pfn)) {
page = pfn_to_page(pfn);
if (atomic)
hva = kmap_atomic(page);
else
hva = kmap(page);
#ifdef CONFIG_HAS_IOMEM
} else if (!atomic) {
hva = memremap(pfn_to_hpa(pfn), PAGE_SIZE, MEMREMAP_WB);
} else {
return -EINVAL;
#endif
}
if (!hva)
return -EFAULT;
map->page = page;
map->hva = hva;
map->pfn = pfn;
map->gfn = gfn;
return 0;
}
int kvm_map_gfn(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map,
struct gfn_to_pfn_cache *cache, bool atomic)
{
return __kvm_map_gfn(kvm_memslots(vcpu->kvm), gfn, map,
cache, atomic);
}
EXPORT_SYMBOL_GPL(kvm_map_gfn);
int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map)
{
return __kvm_map_gfn(kvm_vcpu_memslots(vcpu), gfn, map,
NULL, false);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_map);
static void __kvm_unmap_gfn(struct kvm *kvm,
struct kvm_memory_slot *memslot,
struct kvm_host_map *map,
struct gfn_to_pfn_cache *cache,
bool dirty, bool atomic)
{
if (!map)
return;
if (!map->hva)
return;
if (map->page != KVM_UNMAPPED_PAGE) {
if (atomic)
kunmap_atomic(map->hva);
else
kunmap(map->page);
}
#ifdef CONFIG_HAS_IOMEM
else if (!atomic)
memunmap(map->hva);
else
WARN_ONCE(1, "Unexpected unmapping in atomic context");
#endif
if (dirty)
mark_page_dirty_in_slot(kvm, memslot, map->gfn);
if (cache)
cache->dirty |= dirty;
else
kvm_release_pfn(map->pfn, dirty, NULL);
map->hva = NULL;
map->page = NULL;
}
int kvm_unmap_gfn(struct kvm_vcpu *vcpu, struct kvm_host_map *map,
struct gfn_to_pfn_cache *cache, bool dirty, bool atomic)
{
__kvm_unmap_gfn(vcpu->kvm, gfn_to_memslot(vcpu->kvm, map->gfn), map,
cache, dirty, atomic);
return 0;
}
EXPORT_SYMBOL_GPL(kvm_unmap_gfn);
void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map, bool dirty)
{
__kvm_unmap_gfn(vcpu->kvm, kvm_vcpu_gfn_to_memslot(vcpu, map->gfn),
map, NULL, dirty, false);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_unmap);
struct page *kvm_vcpu_gfn_to_page(struct kvm_vcpu *vcpu, gfn_t gfn)
{
kvm_pfn_t pfn;
pfn = kvm_vcpu_gfn_to_pfn(vcpu, gfn);
return kvm_pfn_to_page(pfn);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_page);
void kvm_release_page_clean(struct page *page)
{
WARN_ON(is_error_page(page));
kvm_release_pfn_clean(page_to_pfn(page));
}
EXPORT_SYMBOL_GPL(kvm_release_page_clean);
void kvm_release_pfn_clean(kvm_pfn_t pfn)
{
if (!is_error_noslot_pfn(pfn) && !kvm_is_reserved_pfn(pfn))
put_page(pfn_to_page(pfn));
}
EXPORT_SYMBOL_GPL(kvm_release_pfn_clean);
void kvm_release_page_dirty(struct page *page)
{
WARN_ON(is_error_page(page));
kvm_release_pfn_dirty(page_to_pfn(page));
}
EXPORT_SYMBOL_GPL(kvm_release_page_dirty);
void kvm_release_pfn_dirty(kvm_pfn_t pfn)
{
kvm_set_pfn_dirty(pfn);
kvm_release_pfn_clean(pfn);
}
EXPORT_SYMBOL_GPL(kvm_release_pfn_dirty);
void kvm_set_pfn_dirty(kvm_pfn_t pfn)
{
if (!kvm_is_reserved_pfn(pfn) && !kvm_is_zone_device_pfn(pfn))
SetPageDirty(pfn_to_page(pfn));
}
EXPORT_SYMBOL_GPL(kvm_set_pfn_dirty);
void kvm_set_pfn_accessed(kvm_pfn_t pfn)
{
if (!kvm_is_reserved_pfn(pfn) && !kvm_is_zone_device_pfn(pfn))
mark_page_accessed(pfn_to_page(pfn));
}
EXPORT_SYMBOL_GPL(kvm_set_pfn_accessed);
void kvm_get_pfn(kvm_pfn_t pfn)
{
if (!kvm_is_reserved_pfn(pfn))
get_page(pfn_to_page(pfn));
}
EXPORT_SYMBOL_GPL(kvm_get_pfn);
static int next_segment(unsigned long len, int offset)
{
if (len > PAGE_SIZE - offset)
return PAGE_SIZE - offset;
else
return len;
}
static int __kvm_read_guest_page(struct kvm_memory_slot *slot, gfn_t gfn,
void *data, int offset, int len)
{
int r;
unsigned long addr;
addr = gfn_to_hva_memslot_prot(slot, gfn, NULL);
if (kvm_is_error_hva(addr))
return -EFAULT;
r = __copy_from_user(data, (void __user *)addr + offset, len);
if (r)
return -EFAULT;
return 0;
}
int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
int len)
{
struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
return __kvm_read_guest_page(slot, gfn, data, offset, len);
}
EXPORT_SYMBOL_GPL(kvm_read_guest_page);
int kvm_vcpu_read_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn, void *data,
int offset, int len)
{
struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
return __kvm_read_guest_page(slot, gfn, data, offset, len);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_page);
int kvm_read_guest(struct kvm *kvm, gpa_t gpa, void *data, unsigned long len)
{
gfn_t gfn = gpa >> PAGE_SHIFT;
int seg;
int offset = offset_in_page(gpa);
int ret;
while ((seg = next_segment(len, offset)) != 0) {
ret = kvm_read_guest_page(kvm, gfn, data, offset, seg);
if (ret < 0)
return ret;
offset = 0;
len -= seg;
data += seg;
++gfn;
}
return 0;
}
EXPORT_SYMBOL_GPL(kvm_read_guest);
int kvm_vcpu_read_guest(struct kvm_vcpu *vcpu, gpa_t gpa, void *data, unsigned long len)
{
gfn_t gfn = gpa >> PAGE_SHIFT;
int seg;
int offset = offset_in_page(gpa);
int ret;
while ((seg = next_segment(len, offset)) != 0) {
ret = kvm_vcpu_read_guest_page(vcpu, gfn, data, offset, seg);
if (ret < 0)
return ret;
offset = 0;
len -= seg;
data += seg;
++gfn;
}
return 0;
}
EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest);
static int __kvm_read_guest_atomic(struct kvm_memory_slot *slot, gfn_t gfn,
void *data, int offset, unsigned long len)
{
int r;
unsigned long addr;
addr = gfn_to_hva_memslot_prot(slot, gfn, NULL);
if (kvm_is_error_hva(addr))
return -EFAULT;
pagefault_disable();
r = __copy_from_user_inatomic(data, (void __user *)addr + offset, len);
pagefault_enable();
if (r)
return -EFAULT;
return 0;
}
int kvm_vcpu_read_guest_atomic(struct kvm_vcpu *vcpu, gpa_t gpa,
void *data, unsigned long len)
{
gfn_t gfn = gpa >> PAGE_SHIFT;
struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
int offset = offset_in_page(gpa);
return __kvm_read_guest_atomic(slot, gfn, data, offset, len);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_read_guest_atomic);
static int __kvm_write_guest_page(struct kvm *kvm,
struct kvm_memory_slot *memslot, gfn_t gfn,
const void *data, int offset, int len)
{
int r;
unsigned long addr;
addr = gfn_to_hva_memslot(memslot, gfn);
if (kvm_is_error_hva(addr))
return -EFAULT;
r = __copy_to_user((void __user *)addr + offset, data, len);
if (r)
return -EFAULT;
mark_page_dirty_in_slot(kvm, memslot, gfn);
return 0;
}
int kvm_write_guest_page(struct kvm *kvm, gfn_t gfn,
const void *data, int offset, int len)
{
struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
return __kvm_write_guest_page(kvm, slot, gfn, data, offset, len);
}
EXPORT_SYMBOL_GPL(kvm_write_guest_page);
int kvm_vcpu_write_guest_page(struct kvm_vcpu *vcpu, gfn_t gfn,
const void *data, int offset, int len)
{
struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
return __kvm_write_guest_page(vcpu->kvm, slot, gfn, data, offset, len);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_write_guest_page);
int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data,
unsigned long len)
{
gfn_t gfn = gpa >> PAGE_SHIFT;
int seg;
int offset = offset_in_page(gpa);
int ret;
while ((seg = next_segment(len, offset)) != 0) {
ret = kvm_write_guest_page(kvm, gfn, data, offset, seg);
if (ret < 0)
return ret;
offset = 0;
len -= seg;
data += seg;
++gfn;
}
return 0;
}
EXPORT_SYMBOL_GPL(kvm_write_guest);
int kvm_vcpu_write_guest(struct kvm_vcpu *vcpu, gpa_t gpa, const void *data,
unsigned long len)
{
gfn_t gfn = gpa >> PAGE_SHIFT;
int seg;
int offset = offset_in_page(gpa);
int ret;
while ((seg = next_segment(len, offset)) != 0) {
ret = kvm_vcpu_write_guest_page(vcpu, gfn, data, offset, seg);
if (ret < 0)
return ret;
offset = 0;
len -= seg;
data += seg;
++gfn;
}
return 0;
}
EXPORT_SYMBOL_GPL(kvm_vcpu_write_guest);
static int __kvm_gfn_to_hva_cache_init(struct kvm_memslots *slots,
struct gfn_to_hva_cache *ghc,
gpa_t gpa, unsigned long len)
{
int offset = offset_in_page(gpa);
gfn_t start_gfn = gpa >> PAGE_SHIFT;
gfn_t end_gfn = (gpa + len - 1) >> PAGE_SHIFT;
gfn_t nr_pages_needed = end_gfn - start_gfn + 1;
gfn_t nr_pages_avail;
/* Update ghc->generation before performing any error checks. */
ghc->generation = slots->generation;
if (start_gfn > end_gfn) {
ghc->hva = KVM_HVA_ERR_BAD;
return -EINVAL;
}
/*
* If the requested region crosses two memslots, we still
* verify that the entire region is valid here.
*/
for ( ; start_gfn <= end_gfn; start_gfn += nr_pages_avail) {
ghc->memslot = __gfn_to_memslot(slots, start_gfn);
ghc->hva = gfn_to_hva_many(ghc->memslot, start_gfn,
&nr_pages_avail);
if (kvm_is_error_hva(ghc->hva))
return -EFAULT;
}
/* Use the slow path for cross page reads and writes. */
if (nr_pages_needed == 1)
ghc->hva += offset;
else
ghc->memslot = NULL;
ghc->gpa = gpa;
ghc->len = len;
return 0;
}
int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
gpa_t gpa, unsigned long len)
{
struct kvm_memslots *slots = kvm_memslots(kvm);
return __kvm_gfn_to_hva_cache_init(slots, ghc, gpa, len);
}
EXPORT_SYMBOL_GPL(kvm_gfn_to_hva_cache_init);
int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
void *data, unsigned int offset,
unsigned long len)
{
struct kvm_memslots *slots = kvm_memslots(kvm);
int r;
gpa_t gpa = ghc->gpa + offset;
BUG_ON(len + offset > ghc->len);
if (slots->generation != ghc->generation) {
if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len))
return -EFAULT;
}
if (kvm_is_error_hva(ghc->hva))
return -EFAULT;
if (unlikely(!ghc->memslot))
return kvm_write_guest(kvm, gpa, data, len);
r = __copy_to_user((void __user *)ghc->hva + offset, data, len);
if (r)
return -EFAULT;
mark_page_dirty_in_slot(kvm, ghc->memslot, gpa >> PAGE_SHIFT);
return 0;
}
EXPORT_SYMBOL_GPL(kvm_write_guest_offset_cached);
int kvm_write_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
void *data, unsigned long len)
{
return kvm_write_guest_offset_cached(kvm, ghc, data, 0, len);
}
EXPORT_SYMBOL_GPL(kvm_write_guest_cached);
int kvm_read_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
void *data, unsigned int offset,
unsigned long len)
{
struct kvm_memslots *slots = kvm_memslots(kvm);
int r;
gpa_t gpa = ghc->gpa + offset;
BUG_ON(len + offset > ghc->len);
if (slots->generation != ghc->generation) {
if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len))
return -EFAULT;
}
if (kvm_is_error_hva(ghc->hva))
return -EFAULT;
if (unlikely(!ghc->memslot))
return kvm_read_guest(kvm, gpa, data, len);
r = __copy_from_user(data, (void __user *)ghc->hva + offset, len);
if (r)
return -EFAULT;
return 0;
}
EXPORT_SYMBOL_GPL(kvm_read_guest_offset_cached);
int kvm_read_guest_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
void *data, unsigned long len)
{
return kvm_read_guest_offset_cached(kvm, ghc, data, 0, len);
}
EXPORT_SYMBOL_GPL(kvm_read_guest_cached);
int kvm_clear_guest(struct kvm *kvm, gpa_t gpa, unsigned long len)
{
const void *zero_page = (const void *) __va(page_to_phys(ZERO_PAGE(0)));
gfn_t gfn = gpa >> PAGE_SHIFT;
int seg;
int offset = offset_in_page(gpa);
int ret;
while ((seg = next_segment(len, offset)) != 0) {
ret = kvm_write_guest_page(kvm, gfn, zero_page, offset, len);
if (ret < 0)
return ret;
offset = 0;
len -= seg;
++gfn;
}
return 0;
}
EXPORT_SYMBOL_GPL(kvm_clear_guest);
void mark_page_dirty_in_slot(struct kvm *kvm,
struct kvm_memory_slot *memslot,
gfn_t gfn)
{
if (memslot && kvm_slot_dirty_track_enabled(memslot)) {
unsigned long rel_gfn = gfn - memslot->base_gfn;
u32 slot = (memslot->as_id << 16) | memslot->id;
if (kvm->dirty_ring_size)
kvm_dirty_ring_push(kvm_dirty_ring_get(kvm),
slot, rel_gfn);
else
set_bit_le(rel_gfn, memslot->dirty_bitmap);
}
}
EXPORT_SYMBOL_GPL(mark_page_dirty_in_slot);
void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
{
struct kvm_memory_slot *memslot;
memslot = gfn_to_memslot(kvm, gfn);
mark_page_dirty_in_slot(kvm, memslot, gfn);
}
EXPORT_SYMBOL_GPL(mark_page_dirty);
void kvm_vcpu_mark_page_dirty(struct kvm_vcpu *vcpu, gfn_t gfn)
{
struct kvm_memory_slot *memslot;
memslot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
mark_page_dirty_in_slot(vcpu->kvm, memslot, gfn);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_mark_page_dirty);
void kvm_sigset_activate(struct kvm_vcpu *vcpu)
{
if (!vcpu->sigset_active)
return;
/*
* This does a lockless modification of ->real_blocked, which is fine
* because, only current can change ->real_blocked and all readers of
* ->real_blocked don't care as long ->real_blocked is always a subset
* of ->blocked.
*/
sigprocmask(SIG_SETMASK, &vcpu->sigset, &current->real_blocked);
}
void kvm_sigset_deactivate(struct kvm_vcpu *vcpu)
{
if (!vcpu->sigset_active)
return;
sigprocmask(SIG_SETMASK, &current->real_blocked, NULL);
sigemptyset(&current->real_blocked);
}
static void grow_halt_poll_ns(struct kvm_vcpu *vcpu)
{
unsigned int old, val, grow, grow_start;
old = val = vcpu->halt_poll_ns;
grow_start = READ_ONCE(halt_poll_ns_grow_start);
grow = READ_ONCE(halt_poll_ns_grow);
if (!grow)
goto out;
val *= grow;
if (val < grow_start)
val = grow_start;
if (val > halt_poll_ns)
val = 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;
old = val = vcpu->halt_poll_ns;
shrink = READ_ONCE(halt_poll_ns_shrink);
if (shrink == 0)
val = 0;
else
val /= shrink;
vcpu->halt_poll_ns = val;
trace_kvm_halt_poll_ns_shrink(vcpu->vcpu_id, val, old);
}
static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu)
{
int ret = -EINTR;
int idx = srcu_read_lock(&vcpu->kvm->srcu);
if (kvm_arch_vcpu_runnable(vcpu)) {
kvm_make_request(KVM_REQ_UNHALT, vcpu);
goto out;
}
if (kvm_cpu_has_pending_timer(vcpu))
goto out;
if (signal_pending(current))
goto out;
ret = 0;
out:
srcu_read_unlock(&vcpu->kvm->srcu, idx);
return ret;
}
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)) {