blob: 70e05af5ebead64cc03218fa60f2f83d7d907941 [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 <linux/suspend.h>
#include <asm/processor.h>
#include <asm/ioctl.h>
#include <linux/uaccess.h>
#include "coalesced_mmio.h"
#include "async_pf.h"
#include "kvm_mm.h"
#include "vfio.h"
#define CREATE_TRACE_POINTS
#include <trace/events/kvm.h>
#include <linux/kvm_dirty_ring.h>
/* Worst case buffer size needed for holding an integer. */
#define ITOA_MAX_LEN 12
MODULE_AUTHOR("Qumranet");
MODULE_LICENSE("GPL");
/* Architectures should define their poll value according to the halt latency */
unsigned int halt_poll_ns = KVM_HALT_POLL_NS_DEFAULT;
module_param(halt_poll_ns, uint, 0644);
EXPORT_SYMBOL_GPL(halt_poll_ns);
/* Default doubles per-vcpu halt_poll_ns. */
unsigned int halt_poll_ns_grow = 2;
module_param(halt_poll_ns_grow, uint, 0644);
EXPORT_SYMBOL_GPL(halt_poll_ns_grow);
/* The start value to grow halt_poll_ns from */
unsigned int halt_poll_ns_grow_start = 10000; /* 10us */
module_param(halt_poll_ns_grow_start, uint, 0644);
EXPORT_SYMBOL_GPL(halt_poll_ns_grow_start);
/* Default resets per-vcpu halt_poll_ns . */
unsigned int halt_poll_ns_shrink;
module_param(halt_poll_ns_shrink, uint, 0644);
EXPORT_SYMBOL_GPL(halt_poll_ns_shrink);
/*
* Ordering of locks:
*
* kvm->lock --> kvm->slots_lock --> kvm->irq_lock
*/
DEFINE_MUTEX(kvm_lock);
static DEFINE_RAW_SPINLOCK(kvm_count_lock);
LIST_HEAD(vm_list);
static cpumask_var_t cpus_hardware_enabled;
static int kvm_usage_count;
static atomic_t hardware_enable_failed;
static struct kmem_cache *kvm_vcpu_cache;
static __read_mostly struct preempt_ops kvm_preempt_ops;
static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_running_vcpu);
struct dentry *kvm_debugfs_dir;
EXPORT_SYMBOL_GPL(kvm_debugfs_dir);
static const struct file_operations stat_fops_per_vm;
static 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)
{
}
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;
}
/*
* 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(struct cpumask *cpus, bool wait)
{
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_vcpu *vcpu, unsigned int req,
struct cpumask *tmp, int current_cpu)
{
int cpu;
if (likely(!(req & KVM_REQUEST_NO_ACTION)))
__kvm_make_request(req, vcpu);
if (!(req & KVM_REQUEST_NO_WAKEUP) && kvm_vcpu_wake_up(vcpu))
return;
/*
* Note, the vCPU could get migrated to a different pCPU at any point
* after kvm_request_needs_ipi(), which could result in sending an IPI
* to the previous pCPU. But, that's OK because the purpose of the IPI
* is to ensure the vCPU returns to OUTSIDE_GUEST_MODE, which is
* satisfied if the vCPU migrates. Entering READING_SHADOW_PAGE_TABLES
* after this point is also OK, as the requirement is only that KVM wait
* for vCPUs that were reading SPTEs _before_ any changes were
* finalized. See kvm_vcpu_kick() for more details on handling requests.
*/
if (kvm_request_needs_ipi(vcpu, req)) {
cpu = READ_ONCE(vcpu->cpu);
if (cpu != -1 && cpu != current_cpu)
__cpumask_set_cpu(cpu, tmp);
}
}
bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
unsigned long *vcpu_bitmap)
{
struct kvm_vcpu *vcpu;
struct cpumask *cpus;
int i, me;
bool called;
me = get_cpu();
cpus = this_cpu_cpumask_var_ptr(cpu_kick_mask);
cpumask_clear(cpus);
for_each_set_bit(i, vcpu_bitmap, KVM_MAX_VCPUS) {
vcpu = kvm_get_vcpu(kvm, i);
if (!vcpu)
continue;
kvm_make_vcpu_request(vcpu, req, cpus, me);
}
called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT));
put_cpu();
return called;
}
bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req,
struct kvm_vcpu *except)
{
struct kvm_vcpu *vcpu;
struct cpumask *cpus;
unsigned long i;
bool called;
int me;
me = get_cpu();
cpus = this_cpu_cpumask_var_ptr(cpu_kick_mask);
cpumask_clear(cpus);
kvm_for_each_vcpu(i, vcpu, kvm) {
if (vcpu == except)
continue;
kvm_make_vcpu_request(vcpu, req, cpus, me);
}
called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT));
put_cpu();
return called;
}
bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
{
return kvm_make_all_cpus_request_except(kvm, req, NULL);
}
EXPORT_SYMBOL_GPL(kvm_make_all_cpus_request);
#ifndef CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL
void kvm_flush_remote_tlbs(struct kvm *kvm)
{
++kvm->stat.generic.remote_tlb_flush_requests;
/*
* We want to publish modifications to the page tables before reading
* mode. Pairs with a memory barrier in arch-specific code.
* - x86: smp_mb__after_srcu_read_unlock in vcpu_enter_guest
* and smp_mb in walk_shadow_page_lockless_begin/end.
* - powerpc: smp_mb in kvmppc_prepare_to_enter.
*
* There is already an smp_mb__after_atomic() before
* kvm_make_all_cpus_request() reads vcpu->mode. We reuse that
* barrier here.
*/
if (!kvm_arch_flush_remote_tlb(kvm)
|| kvm_make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH))
++kvm->stat.generic.remote_tlb_flush;
}
EXPORT_SYMBOL_GPL(kvm_flush_remote_tlbs);
#endif
#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;
#ifndef __KVM_HAVE_ARCH_WQP
rcuwait_init(&vcpu->wait);
#endif
kvm_async_pf_vcpu_init(vcpu);
kvm_vcpu_set_in_spin_loop(vcpu, false);
kvm_vcpu_set_dy_eligible(vcpu, false);
vcpu->preempted = false;
vcpu->ready = false;
preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops);
vcpu->last_used_slot = NULL;
}
static 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);
}
void kvm_destroy_vcpus(struct kvm *kvm)
{
unsigned long i;
struct kvm_vcpu *vcpu;
kvm_for_each_vcpu(i, vcpu, kvm) {
kvm_vcpu_destroy(vcpu);
xa_erase(&kvm->vcpu_array, i);
}
atomic_set(&kvm->online_vcpus, 0);
}
EXPORT_SYMBOL_GPL(kvm_destroy_vcpus);
#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn)
{
return container_of(mn, struct kvm, mmu_notifier);
}
static void kvm_mmu_notifier_invalidate_range(struct mmu_notifier *mn,
struct mm_struct *mm,
unsigned long start, unsigned long end)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
int idx;
idx = srcu_read_lock(&kvm->srcu);
kvm_arch_mmu_notifier_invalidate_range(kvm, start, end);
srcu_read_unlock(&kvm->srcu, idx);
}
typedef bool (*hva_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range);
typedef void (*on_lock_fn_t)(struct kvm *kvm, unsigned long start,
unsigned long end);
struct kvm_hva_range {
unsigned long start;
unsigned long end;
pte_t pte;
hva_handler_t handler;
on_lock_fn_t on_lock;
bool flush_on_ret;
bool may_block;
};
/*
* Use a dedicated stub instead of NULL to indicate that there is no callback
* function/handler. The compiler technically can't guarantee that a real
* function will have a non-zero address, and so it will generate code to
* check for !NULL, whereas comparing against a stub will be elided at compile
* time (unless the compiler is getting long in the tooth, e.g. gcc 4.9).
*/
static void kvm_null_fn(void)
{
}
#define IS_KVM_NULL_FN(fn) ((fn) == (void *)kvm_null_fn)
/* Iterate over each memslot intersecting [start, last] (inclusive) range */
#define kvm_for_each_memslot_in_hva_range(node, slots, start, last) \
for (node = interval_tree_iter_first(&slots->hva_tree, start, last); \
node; \
node = interval_tree_iter_next(node, start, last)) \
static __always_inline int __kvm_handle_hva_range(struct kvm *kvm,
const struct kvm_hva_range *range)
{
bool ret = false, locked = false;
struct kvm_gfn_range gfn_range;
struct kvm_memory_slot *slot;
struct kvm_memslots *slots;
int i, idx;
if (WARN_ON_ONCE(range->end <= range->start))
return 0;
/* A null handler is allowed if and only if on_lock() is provided. */
if (WARN_ON_ONCE(IS_KVM_NULL_FN(range->on_lock) &&
IS_KVM_NULL_FN(range->handler)))
return 0;
idx = srcu_read_lock(&kvm->srcu);
for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
struct interval_tree_node *node;
slots = __kvm_memslots(kvm, i);
kvm_for_each_memslot_in_hva_range(node, slots,
range->start, range->end - 1) {
unsigned long hva_start, hva_end;
slot = container_of(node, struct kvm_memory_slot, hva_node[slots->node_idx]);
hva_start = max(range->start, slot->userspace_addr);
hva_end = min(range->end, slot->userspace_addr +
(slot->npages << PAGE_SHIFT));
/*
* To optimize for the likely case where the address
* range is covered by zero or one memslots, don't
* bother making these conditional (to avoid writes on
* the second or later invocation of the handler).
*/
gfn_range.pte = range->pte;
gfn_range.may_block = range->may_block;
/*
* {gfn(page) | page intersects with [hva_start, hva_end)} =
* {gfn_start, gfn_start+1, ..., gfn_end-1}.
*/
gfn_range.start = hva_to_gfn_memslot(hva_start, slot);
gfn_range.end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, slot);
gfn_range.slot = slot;
if (!locked) {
locked = true;
KVM_MMU_LOCK(kvm);
if (!IS_KVM_NULL_FN(range->on_lock))
range->on_lock(kvm, range->start, range->end);
if (IS_KVM_NULL_FN(range->handler))
break;
}
ret |= range->handler(kvm, &gfn_range);
}
}
if (range->flush_on_ret && ret)
kvm_flush_remote_tlbs(kvm);
if (locked)
KVM_MMU_UNLOCK(kvm);
srcu_read_unlock(&kvm->srcu, idx);
/* The notifiers are averse to booleans. :-( */
return (int)ret;
}
static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn,
unsigned long start,
unsigned long end,
pte_t pte,
hva_handler_t handler)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
const struct kvm_hva_range range = {
.start = start,
.end = end,
.pte = pte,
.handler = handler,
.on_lock = (void *)kvm_null_fn,
.flush_on_ret = true,
.may_block = false,
};
return __kvm_handle_hva_range(kvm, &range);
}
static __always_inline int kvm_handle_hva_range_no_flush(struct mmu_notifier *mn,
unsigned long start,
unsigned long end,
hva_handler_t handler)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
const struct kvm_hva_range range = {
.start = start,
.end = end,
.pte = __pte(0),
.handler = handler,
.on_lock = (void *)kvm_null_fn,
.flush_on_ret = false,
.may_block = false,
};
return __kvm_handle_hva_range(kvm, &range);
}
static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn,
struct mm_struct *mm,
unsigned long address,
pte_t pte)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
trace_kvm_set_spte_hva(address);
/*
* .change_pte() must be surrounded by .invalidate_range_{start,end}().
* If mmu_notifier_count is zero, then no in-progress invalidations,
* including this one, found a relevant memslot at start(); rechecking
* memslots here is unnecessary. Note, a false positive (count elevated
* by a different invalidation) is sub-optimal but functionally ok.
*/
WARN_ON_ONCE(!READ_ONCE(kvm->mn_active_invalidate_count));
if (!READ_ONCE(kvm->mmu_notifier_count))
return;
kvm_handle_hva_range(mn, address, address + 1, pte, kvm_set_spte_gfn);
}
void kvm_inc_notifier_count(struct kvm *kvm, unsigned long start,
unsigned long end)
{
/*
* The count increase must become visible at unlock time as no
* spte can be established without taking the mmu_lock and
* count is also read inside the mmu_lock critical section.
*/
kvm->mmu_notifier_count++;
if (likely(kvm->mmu_notifier_count == 1)) {
kvm->mmu_notifier_range_start = start;
kvm->mmu_notifier_range_end = end;
} else {
/*
* Fully tracking multiple concurrent ranges has dimishing
* returns. Keep things simple and just find the minimal range
* which includes the current and new ranges. As there won't be
* enough information to subtract a range after its invalidate
* completes, any ranges invalidated concurrently will
* accumulate and persist until all outstanding invalidates
* complete.
*/
kvm->mmu_notifier_range_start =
min(kvm->mmu_notifier_range_start, start);
kvm->mmu_notifier_range_end =
max(kvm->mmu_notifier_range_end, end);
}
}
static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
const struct mmu_notifier_range *range)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
const struct kvm_hva_range hva_range = {
.start = range->start,
.end = range->end,
.pte = __pte(0),
.handler = kvm_unmap_gfn_range,
.on_lock = kvm_inc_notifier_count,
.flush_on_ret = true,
.may_block = mmu_notifier_range_blockable(range),
};
trace_kvm_unmap_hva_range(range->start, range->end);
/*
* Prevent memslot modification between range_start() and range_end()
* so that conditionally locking provides the same result in both
* functions. Without that guarantee, the mmu_notifier_count
* adjustments will be imbalanced.
*
* Pairs with the decrement in range_end().
*/
spin_lock(&kvm->mn_invalidate_lock);
kvm->mn_active_invalidate_count++;
spin_unlock(&kvm->mn_invalidate_lock);
gfn_to_pfn_cache_invalidate_start(kvm, range->start, range->end,
hva_range.may_block);
__kvm_handle_hva_range(kvm, &hva_range);
return 0;
}
void kvm_dec_notifier_count(struct kvm *kvm, unsigned long start,
unsigned long end)
{
/*
* This sequence increase will notify the kvm page fault that
* the page that is going to be mapped in the spte could have
* been freed.
*/
kvm->mmu_notifier_seq++;
smp_wmb();
/*
* The above sequence increase must be visible before the
* below count decrease, which is ensured by the smp_wmb above
* in conjunction with the smp_rmb in mmu_notifier_retry().
*/
kvm->mmu_notifier_count--;
}
static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,
const struct mmu_notifier_range *range)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
const struct kvm_hva_range hva_range = {
.start = range->start,
.end = range->end,
.pte = __pte(0),
.handler = (void *)kvm_null_fn,
.on_lock = kvm_dec_notifier_count,
.flush_on_ret = false,
.may_block = mmu_notifier_range_blockable(range),
};
bool wake;
__kvm_handle_hva_range(kvm, &hva_range);
/* Pairs with the increment in range_start(). */
spin_lock(&kvm->mn_invalidate_lock);
wake = (--kvm->mn_active_invalidate_count == 0);
spin_unlock(&kvm->mn_invalidate_lock);
/*
* There can only be one waiter, since the wait happens under
* slots_lock.
*/
if (wake)
rcuwait_wake_up(&kvm->mn_memslots_update_rcuwait);
BUG_ON(kvm->mmu_notifier_count < 0);
}
static int kvm_mmu_notifier_clear_flush_young(struct mmu_notifier *mn,
struct mm_struct *mm,
unsigned long start,
unsigned long end)
{
trace_kvm_age_hva(start, end);
return kvm_handle_hva_range(mn, start, end, __pte(0), kvm_age_gfn);
}
static int kvm_mmu_notifier_clear_young(struct mmu_notifier *mn,
struct mm_struct *mm,
unsigned long start,
unsigned long end)
{
trace_kvm_age_hva(start, end);
/*
* Even though we do not flush TLB, this will still adversely
* affect performance on pre-Haswell Intel EPT, where there is
* no EPT Access Bit to clear so that we have to tear down EPT
* tables instead. If we find this unacceptable, we can always
* add a parameter to kvm_age_hva so that it effectively doesn't
* do anything on clear_young.
*
* Also note that currently we never issue secondary TLB flushes
* from clear_young, leaving this job up to the regular system
* cadence. If we find this inaccurate, we might come up with a
* more sophisticated heuristic later.
*/
return kvm_handle_hva_range_no_flush(mn, start, end, kvm_age_gfn);
}
static int kvm_mmu_notifier_test_young(struct mmu_notifier *mn,
struct mm_struct *mm,
unsigned long address)
{
trace_kvm_test_age_hva(address);
return kvm_handle_hva_range_no_flush(mn, address, address + 1,
kvm_test_age_gfn);
}
static void kvm_mmu_notifier_release(struct mmu_notifier *mn,
struct mm_struct *mm)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
int idx;
idx = srcu_read_lock(&kvm->srcu);
kvm_arch_flush_shadow_all(kvm);
srcu_read_unlock(&kvm->srcu, idx);
}
static const struct mmu_notifier_ops kvm_mmu_notifier_ops = {
.invalidate_range = kvm_mmu_notifier_invalidate_range,
.invalidate_range_start = kvm_mmu_notifier_invalidate_range_start,
.invalidate_range_end = kvm_mmu_notifier_invalidate_range_end,
.clear_flush_young = kvm_mmu_notifier_clear_flush_young,
.clear_young = kvm_mmu_notifier_clear_young,
.test_young = kvm_mmu_notifier_test_young,
.change_pte = kvm_mmu_notifier_change_pte,
.release = kvm_mmu_notifier_release,
};
static int kvm_init_mmu_notifier(struct kvm *kvm)
{
kvm->mmu_notifier.ops = &kvm_mmu_notifier_ops;
return mmu_notifier_register(&kvm->mmu_notifier, current->mm);
}
#else /* !(CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER) */
static int kvm_init_mmu_notifier(struct kvm *kvm)
{
return 0;
}
#endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */
#ifdef CONFIG_HAVE_KVM_PM_NOTIFIER
static int kvm_pm_notifier_call(struct notifier_block *bl,
unsigned long state,
void *unused)
{
struct kvm *kvm = container_of(bl, struct kvm, pm_notifier);
return kvm_arch_pm_notifier(kvm, state);
}
static void kvm_init_pm_notifier(struct kvm *kvm)
{
kvm->pm_notifier.notifier_call = kvm_pm_notifier_call;
/* Suspend KVM before we suspend ftrace, RCU, etc. */
kvm->pm_notifier.priority = INT_MAX;
register_pm_notifier(&kvm->pm_notifier);
}
static void kvm_destroy_pm_notifier(struct kvm *kvm)
{
unregister_pm_notifier(&kvm->pm_notifier);
}
#else /* !CONFIG_HAVE_KVM_PM_NOTIFIER */
static void kvm_init_pm_notifier(struct kvm *kvm)
{
}
static void kvm_destroy_pm_notifier(struct kvm *kvm)
{
}
#endif /* CONFIG_HAVE_KVM_PM_NOTIFIER */
static void kvm_destroy_dirty_bitmap(struct kvm_memory_slot *memslot)
{
if (!memslot->dirty_bitmap)
return;
kvfree(memslot->dirty_bitmap);
memslot->dirty_bitmap = NULL;
}
/* This does not remove the slot from struct kvm_memslots data structures */
static void kvm_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot)
{
kvm_destroy_dirty_bitmap(slot);
kvm_arch_free_memslot(kvm, slot);
kfree(slot);
}
static void kvm_free_memslots(struct kvm *kvm, struct kvm_memslots *slots)
{
struct hlist_node *idnode;
struct kvm_memory_slot *memslot;
int bkt;
/*
* The same memslot objects live in both active and inactive sets,
* arbitrarily free using index '1' so the second invocation of this
* function isn't operating over a structure with dangling pointers
* (even though this function isn't actually touching them).
*/
if (!slots->node_idx)
return;
hash_for_each_safe(slots->id_hash, bkt, idnode, memslot, id_node[1])
kvm_free_memslot(kvm, memslot);
}
static umode_t kvm_stats_debugfs_mode(const struct _kvm_stats_desc *pdesc)
{
switch (pdesc->desc.flags & KVM_STATS_TYPE_MASK) {
case KVM_STATS_TYPE_INSTANT:
return 0444;
case KVM_STATS_TYPE_CUMULATIVE:
case KVM_STATS_TYPE_PEAK:
default:
return 0644;
}
}
static void kvm_destroy_vm_debugfs(struct kvm *kvm)
{
int i;
int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc +
kvm_vcpu_stats_header.num_desc;
if (!kvm->debugfs_dentry)
return;
debugfs_remove_recursive(kvm->debugfs_dentry);
if (kvm->debugfs_stat_data) {
for (i = 0; i < kvm_debugfs_num_entries; i++)
kfree(kvm->debugfs_stat_data[i]);
kfree(kvm->debugfs_stat_data);
}
}
static int kvm_create_vm_debugfs(struct kvm *kvm, int fd)
{
static DEFINE_MUTEX(kvm_debugfs_lock);
struct dentry *dent;
char dir_name[ITOA_MAX_LEN * 2];
struct kvm_stat_data *stat_data;
const struct _kvm_stats_desc *pdesc;
int i, ret;
int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc +
kvm_vcpu_stats_header.num_desc;
if (!debugfs_initialized())
return 0;
snprintf(dir_name, sizeof(dir_name), "%d-%d", task_pid_nr(current), fd);
mutex_lock(&kvm_debugfs_lock);
dent = debugfs_lookup(dir_name, kvm_debugfs_dir);
if (dent) {
pr_warn_ratelimited("KVM: debugfs: duplicate directory %s\n", dir_name);
dput(dent);
mutex_unlock(&kvm_debugfs_lock);
return 0;
}
dent = debugfs_create_dir(dir_name, kvm_debugfs_dir);
mutex_unlock(&kvm_debugfs_lock);
if (IS_ERR(dent))
return 0;
kvm->debugfs_dentry = dent;
kvm->debugfs_stat_data = kcalloc(kvm_debugfs_num_entries,
sizeof(*kvm->debugfs_stat_data),
GFP_KERNEL_ACCOUNT);
if (!kvm->debugfs_stat_data)
return -ENOMEM;
for (i = 0; i < kvm_vm_stats_header.num_desc; ++i) {
pdesc = &kvm_vm_stats_desc[i];
stat_data = kzalloc(sizeof(*stat_data), GFP_KERNEL_ACCOUNT);
if (!stat_data)
return -ENOMEM;
stat_data->kvm = kvm;
stat_data->desc = pdesc;
stat_data->kind = KVM_STAT_VM;
kvm->debugfs_stat_data[i] = stat_data;
debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
kvm->debugfs_dentry, stat_data,
&stat_fops_per_vm);
}
for (i = 0; i < kvm_vcpu_stats_header.num_desc; ++i) {
pdesc = &kvm_vcpu_stats_desc[i];
stat_data = kzalloc(sizeof(*stat_data), GFP_KERNEL_ACCOUNT);
if (!stat_data)
return -ENOMEM;
stat_data->kvm = kvm;
stat_data->desc = pdesc;
stat_data->kind = KVM_STAT_VCPU;
kvm->debugfs_stat_data[i + kvm_vm_stats_header.num_desc] = stat_data;
debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
kvm->debugfs_dentry, stat_data,
&stat_fops_per_vm);
}
ret = kvm_arch_create_vm_debugfs(kvm);
if (ret) {
kvm_destroy_vm_debugfs(kvm);
return i;
}
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)
{
}
/*
* Called after per-vm debugfs created. When called kvm->debugfs_dentry should
* be setup already, so we can create arch-specific debugfs entries under it.
* Cleanup should be automatic done in kvm_destroy_vm_debugfs() recursively, so
* a per-arch destroy interface is not needed.
*/
int __weak kvm_arch_create_vm_debugfs(struct kvm *kvm)
{
return 0;
}
static struct kvm *kvm_create_vm(unsigned long type)
{
struct kvm *kvm = kvm_arch_alloc_vm();
struct kvm_memslots *slots;
int r = -ENOMEM;
int i, j;
if (!kvm)
return ERR_PTR(-ENOMEM);
KVM_MMU_LOCK_INIT(kvm);
mmgrab(current->mm);
kvm->mm = current->mm;
kvm_eventfd_init(kvm);
mutex_init(&kvm->lock);
mutex_init(&kvm->irq_lock);
mutex_init(&kvm->slots_lock);
mutex_init(&kvm->slots_arch_lock);
spin_lock_init(&kvm->mn_invalidate_lock);
rcuwait_init(&kvm->mn_memslots_update_rcuwait);
xa_init(&kvm->vcpu_array);
INIT_LIST_HEAD(&kvm->gpc_list);
spin_lock_init(&kvm->gpc_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++) {
for (j = 0; j < 2; j++) {
slots = &kvm->__memslots[i][j];
atomic_long_set(&slots->last_used_slot, (unsigned long)NULL);
slots->hva_tree = RB_ROOT_CACHED;
slots->gfn_tree = RB_ROOT;
hash_init(slots->id_hash);
slots->node_idx = j;
/* Generations must be different for each address space. */
slots->generation = i;
}
rcu_assign_pointer(kvm->memslots[i], &kvm->__memslots[i][0]);
}
for (i = 0; i < KVM_NR_BUSES; i++) {
rcu_assign_pointer(kvm->buses[i],
kzalloc(sizeof(struct kvm_io_bus), GFP_KERNEL_ACCOUNT));
if (!kvm->buses[i])
goto out_err_no_arch_destroy_vm;
}
kvm->max_halt_poll_ns = halt_poll_ns;
r = kvm_arch_init_vm(kvm, type);
if (r)
goto out_err_no_arch_destroy_vm;
r = hardware_enable_all();
if (r)
goto out_err_no_disable;
#ifdef CONFIG_HAVE_KVM_IRQFD
INIT_HLIST_HEAD(&kvm->irq_ack_notifier_list);
#endif
r = kvm_init_mmu_notifier(kvm);
if (r)
goto out_err_no_mmu_notifier;
r = kvm_arch_post_init_vm(kvm);
if (r)
goto out_err;
mutex_lock(&kvm_lock);
list_add(&kvm->vm_list, &vm_list);
mutex_unlock(&kvm_lock);
preempt_notifier_inc();
kvm_init_pm_notifier(kvm);
/*
* 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));
cleanup_srcu_struct(&kvm->irq_srcu);
out_err_no_irq_srcu:
cleanup_srcu_struct(&kvm->srcu);
out_err_no_srcu:
kvm_arch_free_vm(kvm);
mmdrop(current->mm);
return ERR_PTR(r);
}
static void kvm_destroy_devices(struct kvm *kvm)
{
struct kvm_device *dev, *tmp;
/*
* We do not need to take the kvm->lock here, because nobody else
* has a reference to the struct kvm at this point and therefore
* cannot access the devices list anyhow.
*/
list_for_each_entry_safe(dev, tmp, &kvm->devices, vm_node) {
list_del(&dev->vm_node);
dev->ops->destroy(dev);
}
}
static void kvm_destroy_vm(struct kvm *kvm)
{
int i;
struct mm_struct *mm = kvm->mm;
kvm_destroy_pm_notifier(kvm);
kvm_uevent_notify_change(KVM_EVENT_DESTROY_VM, kvm);
kvm_destroy_vm_debugfs(kvm);
kvm_arch_sync_events(kvm);
mutex_lock(&kvm_lock);
list_del(&kvm->vm_list);
mutex_unlock(&kvm_lock);
kvm_arch_pre_destroy_vm(kvm);
kvm_free_irq_routing(kvm);
for (i = 0; i < KVM_NR_BUSES; i++) {
struct kvm_io_bus *bus = kvm_get_bus(kvm, i);
if (bus)
kvm_io_bus_destroy(bus);
kvm->buses[i] = NULL;
}
kvm_coalesced_mmio_free(kvm);
#if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
mmu_notifier_unregister(&kvm->mmu_notifier, kvm->mm);
/*
* At this point, pending calls to invalidate_range_start()
* have completed but no more MMU notifiers will run, so
* mn_active_invalidate_count may remain unbalanced.
* No threads can be waiting in install_new_memslots as the
* last reference on KVM has been dropped, but freeing
* memslots would deadlock without this manual intervention.
*/
WARN_ON(rcuwait_active(&kvm->mn_memslots_update_rcuwait));
kvm->mn_active_invalidate_count = 0;
#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[i][0]);
kvm_free_memslots(kvm, &kvm->__memslots[i][1]);
}
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);
/*
* Make sure the vm is not during destruction, which is a safe version of
* kvm_get_kvm(). Return true if kvm referenced successfully, false otherwise.
*/
bool kvm_get_kvm_safe(struct kvm *kvm)
{
return refcount_inc_not_zero(&kvm->users_count);
}
EXPORT_SYMBOL_GPL(kvm_get_kvm_safe);
void kvm_put_kvm(struct kvm *kvm)
{
if (refcount_dec_and_test(&kvm->users_count))
kvm_destroy_vm(kvm);
}
EXPORT_SYMBOL_GPL(kvm_put_kvm);
/*
* Used to put a reference that was taken on behalf of an object associated
* with a user-visible file descriptor, e.g. a vcpu or device, if installation
* of the new file descriptor fails and the reference cannot be transferred to
* its final owner. In such cases, the caller is still actively using @kvm and
* will fail miserably if the refcount unexpectedly hits zero.
*/
void kvm_put_kvm_no_destroy(struct kvm *kvm)
{
WARN_ON(refcount_dec_and_test(&kvm->users_count));
}
EXPORT_SYMBOL_GPL(kvm_put_kvm_no_destroy);
static int kvm_vm_release(struct inode *inode, struct file *filp)
{
struct kvm *kvm = filp->private_data;
kvm_irqfd_release(kvm);
kvm_put_kvm(kvm);
return 0;
}
/*
* Allocation size is twice as large as the actual dirty bitmap size.
* See kvm_vm_ioctl_get_dirty_log() why this is needed.
*/
static int kvm_alloc_dirty_bitmap(struct kvm_memory_slot *memslot)
{
unsigned long dirty_bytes = kvm_dirty_bitmap_bytes(memslot);
memslot->dirty_bitmap = __vcalloc(2, dirty_bytes, GFP_KERNEL_ACCOUNT);
if (!memslot->dirty_bitmap)
return -ENOMEM;
return 0;
}
static struct kvm_memslots *kvm_get_inactive_memslots(struct kvm *kvm, int as_id)
{
struct kvm_memslots *active = __kvm_memslots(kvm, as_id);
int node_idx_inactive = active->node_idx ^ 1;
return &kvm->__memslots[as_id][node_idx_inactive];
}
/*
* Helper to get the address space ID when one of memslot pointers may be NULL.
* This also serves as a sanity that at least one of the pointers is non-NULL,
* and that their address space IDs don't diverge.
*/
static int kvm_memslots_get_as_id(struct kvm_memory_slot *a,
struct kvm_memory_slot *b)
{
if (WARN_ON_ONCE(!a && !b))
return 0;
if (!a)
return b->as_id;
if (!b)
return a->as_id;
WARN_ON_ONCE(a->as_id != b->as_id);
return a->as_id;
}
static void kvm_insert_gfn_node(struct kvm_memslots *slots,
struct kvm_memory_slot *slot)
{
struct rb_root *gfn_tree = &slots->gfn_tree;
struct rb_node **node, *parent;
int idx = slots->node_idx;
parent = NULL;
for (node = &gfn_tree->rb_node; *node; ) {
struct kvm_memory_slot *tmp;
tmp = container_of(*node, struct kvm_memory_slot, gfn_node[idx]);
parent = *node;
if (slot->base_gfn < tmp->base_gfn)
node = &(*node)->rb_left;
else if (slot->base_gfn > tmp->base_gfn)
node = &(*node)->rb_right;
else
BUG();
}
rb_link_node(&slot->gfn_node[idx], parent, node);
rb_insert_color(&slot->gfn_node[idx], gfn_tree);
}
static void kvm_erase_gfn_node(struct kvm_memslots *slots,
struct kvm_memory_slot *slot)
{
rb_erase(&slot->gfn_node[slots->node_idx], &slots->gfn_tree);
}
static void kvm_replace_gfn_node(struct kvm_memslots *slots,
struct kvm_memory_slot *old,
struct kvm_memory_slot *new)
{
int idx = slots->node_idx;
WARN_ON_ONCE(old->base_gfn != new->base_gfn);
rb_replace_node(&old->gfn_node[idx], &new->gfn_node[idx],
&slots->gfn_tree);
}
/*
* Replace @old with @new in the inactive memslots.
*
* With NULL @old this simply adds @new.
* With NULL @new this simply removes @old.
*
* If @new is non-NULL its hva_node[slots_idx] range has to be set
* appropriately.
*/
static void kvm_replace_memslot(struct kvm *kvm,
struct kvm_memory_slot *old,
struct kvm_memory_slot *new)
{
int as_id = kvm_memslots_get_as_id(old, new);
struct kvm_memslots *slots = kvm_get_inactive_memslots(kvm, as_id);
int idx = slots->node_idx;
if (old) {
hash_del(&old->id_node[idx]);
interval_tree_remove(&old->hva_node[idx], &slots->hva_tree);
if ((long)old == atomic_long_read(&slots->last_used_slot))
atomic_long_set(&slots->last_used_slot, (long)new);
if (!new) {
kvm_erase_gfn_node(slots, old);
return;
}
}
/*
* Initialize @new's hva range. Do this even when replacing an @old
* slot, kvm_copy_memslot() deliberately does not touch node data.
*/
new->hva_node[idx].start = new->userspace_addr;
new->hva_node[idx].last = new->userspace_addr +
(new->npages << PAGE_SHIFT) - 1;
/*
* (Re)Add the new memslot. There is no O(1) interval_tree_replace(),
* hva_node needs to be swapped with remove+insert even though hva can't
* change when replacing an existing slot.
*/
hash_add(slots->id_hash, &new->id_node[idx], new->id);
interval_tree_insert(&new->hva_node[idx], &slots->hva_tree);
/*
* If the memslot gfn is unchanged, rb_replace_node() can be used to
* switch the node in the gfn tree instead of removing the old and
* inserting the new as two separate operations. Replacement is a
* single O(1) operation versus two O(log(n)) operations for
* remove+insert.
*/
if (old && old->base_gfn == new->base_gfn) {
kvm_replace_gfn_node(slots, old, new);
} else {
if (old)
kvm_erase_gfn_node(slots, old);
kvm_insert_gfn_node(slots, new);
}
}
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 void kvm_swap_active_memslots(struct kvm *kvm, int as_id)
{
struct kvm_memslots *slots = kvm_get_inactive_memslots(kvm, as_id);
/* Grab the generation from the activate memslots. */
u64 gen = __kvm_memslots(kvm, as_id)->generation;
WARN_ON(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS);
slots->generation = gen | KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS;
/*
* Do not store the new memslots while there are invalidations in
* progress, otherwise the locking in invalidate_range_start and
* invalidate_range_end will be unbalanced.
*/
spin_lock(&kvm->mn_invalidate_lock);
prepare_to_rcuwait(&kvm->mn_memslots_update_rcuwait);
while (kvm->mn_active_invalidate_count) {
set_current_state(TASK_UNINTERRUPTIBLE);
spin_unlock(&kvm->mn_invalidate_lock);
schedule();
spin_lock(&kvm->mn_invalidate_lock);
}
finish_rcuwait(&kvm->mn_memslots_update_rcuwait);
rcu_assign_pointer(kvm->memslots[as_id], slots);
spin_unlock(&kvm->mn_invalidate_lock);
/*
* Acquired in kvm_set_memslot. Must be released before synchronize
* SRCU below in order to avoid deadlock with another thread
* acquiring the slots_arch_lock in an srcu critical section.
*/
mutex_unlock(&kvm->slots_arch_lock);
synchronize_srcu_expedited(&kvm->srcu);
/*
* Increment the new memslot generation a second time, dropping the
* update in-progress flag and incrementing the generation based on
* the number of address spaces. This provides a unique and easily
* identifiable generation number while the memslots are in flux.
*/
gen = slots->generation & ~KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS;
/*
* Generations must be unique even across address spaces. We do not need
* a global counter for that, instead the generation space is evenly split
* across address spaces. For example, with two address spaces, address
* space 0 will use generations 0, 2, 4, ... while address space 1 will
* use generations 1, 3, 5, ...
*/
gen += KVM_ADDRESS_SPACE_NUM;
kvm_arch_memslots_updated(kvm, gen);
slots->generation = gen;
}
static int kvm_prepare_memory_region(struct kvm *kvm,
const struct kvm_memory_slot *old,
struct kvm_memory_slot *new,
enum kvm_mr_change change)
{
int r;
/*
* If dirty logging is disabled, nullify the bitmap; the old bitmap
* will be freed on "commit". If logging is enabled in both old and
* new, reuse the existing bitmap. If logging is enabled only in the
* new and KVM isn't using a ring buffer, allocate and initialize a
* new bitmap.
*/
if (change != KVM_MR_DELETE) {
if (!(new->flags & KVM_MEM_LOG_DIRTY_PAGES))
new->dirty_bitmap = NULL;
else if (old && old->dirty_bitmap)
new->dirty_bitmap = old->dirty_bitmap;
else if (!kvm->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_arch_prepare_memory_region(kvm, old, new, change);
/* Free the bitmap on failure if it was allocated above. */
if (r && new && new->dirty_bitmap && old && !old->dirty_bitmap)
kvm_destroy_dirty_bitmap(new);
return r;
}
static void kvm_commit_memory_region(struct kvm *kvm,
struct kvm_memory_slot *old,
const struct kvm_memory_slot *new,
enum kvm_mr_change change)
{
/*
* Update the total number of memslot pages before calling the arch
* hook so that architectures can consume the result directly.
*/
if (change == KVM_MR_DELETE)
kvm->nr_memslot_pages -= old->npages;
else if (change == KVM_MR_CREATE)
kvm->nr_memslot_pages += new->npages;
kvm_arch_commit_memory_region(kvm, old, new, change);
switch (change) {
case KVM_MR_CREATE:
/* Nothing more to do. */
break;
case KVM_MR_DELETE:
/* Free the old memslot and all its metadata. */
kvm_free_memslot(kvm, old);
break;
case KVM_MR_MOVE:
case KVM_MR_FLAGS_ONLY:
/*
* Free the dirty bitmap as needed; the below check encompasses
* both the flags and whether a ring buffer is being used)
*/
if (old->dirty_bitmap && !new->dirty_bitmap)
kvm_destroy_dirty_bitmap(old);
/*
* The final quirk. Free the detached, old slot, but only its
* memory, not any metadata. Metadata, including arch specific
* data, may be reused by @new.
*/
kfree(old);
break;
default:
BUG();
}
}
/*
* Activate @new, which must be installed in the inactive slots by the caller,
* by swapping the active slots and then propagating @new to @old once @old is
* unreachable and can be safely modified.
*
* With NULL @old this simply adds @new to @active (while swapping the sets).
* With NULL @new this simply removes @old from @active and frees it
* (while also swapping the sets).
*/
static void kvm_activate_memslot(struct kvm *kvm,
struct kvm_memory_slot *old,
struct kvm_memory_slot *new)
{
int as_id = kvm_memslots_get_as_id(old, new);
kvm_swap_active_memslots(kvm, as_id);
/* Propagate the new memslot to the now inactive memslots. */
kvm_replace_memslot(kvm, old, new);
}
static void kvm_copy_memslot(struct kvm_memory_slot *dest,
const struct kvm_memory_slot *src)
{
dest->base_gfn = src->base_gfn;
dest->npages = src->npages;
dest->dirty_bitmap = src->dirty_bitmap;
dest->arch = src->arch;
dest->userspace_addr = src->userspace_addr;
dest->flags = src->flags;
dest->id = src->id;
dest->as_id = src->as_id;
}
static void kvm_invalidate_memslot(struct kvm *kvm,
struct kvm_memory_slot *old,
struct kvm_memory_slot *invalid_slot)
{
/*
* Mark the current slot INVALID. As with all memslot modifications,
* this must be done on an unreachable slot to avoid modifying the
* current slot in the active tree.
*/
kvm_copy_memslot(invalid_slot, old);
invalid_slot->flags |= KVM_MEMSLOT_INVALID;
kvm_replace_memslot(kvm, old, invalid_slot);
/*
* Activate the slot that is now marked INVALID, but don't propagate
* the slot to the now inactive slots. The slot is either going to be
* deleted or recreated as a new slot.
*/
kvm_swap_active_memslots(kvm, old->as_id);
/*
* From this point no new shadow pages pointing to a deleted, or moved,
* memslot will be created. Validation of sp->gfn happens in:
* - gfn_to_hva (kvm_read_guest, gfn_to_pfn)
* - kvm_is_visible_gfn (mmu_check_root)
*/
kvm_arch_flush_shadow_memslot(kvm, old);
/* Was released by kvm_swap_active_memslots, reacquire. */
mutex_lock(&kvm->slots_arch_lock);
/*
* Copy the arch-specific field of the newly-installed slot back to the
* old slot as the arch data could have changed between releasing
* slots_arch_lock in install_new_memslots() and re-acquiring the lock
* above. Writers are required to retrieve memslots *after* acquiring
* slots_arch_lock, thus the active slot's data is guaranteed to be fresh.
*/
old->arch = invalid_slot->arch;
}
static void kvm_create_memslot(struct kvm *kvm,
struct kvm_memory_slot *new)
{
/* Add the new memslot to the inactive set and activate. */
kvm_replace_memslot(kvm, NULL, new);
kvm_activate_memslot(kvm, NULL, new);
}
static void kvm_delete_memslot(struct kvm *kvm,
struct kvm_memory_slot *old,
struct kvm_memory_slot *invalid_slot)
{
/*
* Remove the old memslot (in the inactive memslots) by passing NULL as
* the "new" slot, and for the invalid version in the active slots.
*/
kvm_replace_memslot(kvm, old, NULL);
kvm_activate_memslot(kvm, invalid_slot, NULL);
}
static void kvm_move_memslot(struct kvm *kvm,
struct kvm_memory_slot *old,
struct kvm_memory_slot *new,
struct kvm_memory_slot *invalid_slot)
{
/*
* Replace the old memslot in the inactive slots, and then swap slots
* and replace the current INVALID with the new as well.
*/
kvm_replace_memslot(kvm, old, new);
kvm_activate_memslot(kvm, invalid_slot, new);
}
static void kvm_update_flags_memslot(struct kvm *kvm,
struct kvm_memory_slot *old,
struct kvm_memory_slot *new)
{
/*
* Similar to the MOVE case, but the slot doesn't need to be zapped as
* an intermediate step. Instead, the old memslot is simply replaced
* with a new, updated copy in both memslot sets.
*/
kvm_replace_memslot(kvm, old, new);
kvm_activate_memslot(kvm, old, new);
}
static int kvm_set_memslot(struct kvm *kvm,
struct kvm_memory_slot *old,
struct kvm_memory_slot *new,
enum kvm_mr_change change)
{
struct kvm_memory_slot *invalid_slot;
int r;
/*
* Released in kvm_swap_active_memslots.
*
* Must be held from before the current memslots are copied until
* after the new memslots are installed with rcu_assign_pointer,
* then released before the synchronize srcu in kvm_swap_active_memslots.
*
* When modifying memslots outside of the slots_lock, must be held
* before reading the pointer to the current memslots until after all
* changes to those memslots are complete.
*
* These rules ensure that installing new memslots does not lose
* changes made to the previous memslots.
*/
mutex_lock(&kvm->slots_arch_lock);
/*
* Invalidate the old slot if it's being deleted or moved. This is
* done prior to actually deleting/moving the memslot to allow vCPUs to
* continue running by ensuring there are no mappings or shadow pages
* for the memslot when it is deleted/moved. Without pre-invalidation
* (and without a lock), a window would exist between effecting the
* delete/move and committing the changes in arch code where KVM or a
* guest could access a non-existent memslot.
*
* Modifications are done on a temporary, unreachable slot. The old
* slot needs to be preserved in case a later step fails and the
* invalidation needs to be reverted.
*/
if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) {
invalid_slot = kzalloc(sizeof(*invalid_slot), GFP_KERNEL_ACCOUNT);
if (!invalid_slot) {
mutex_unlock(&kvm->slots_arch_lock);
return -ENOMEM;
}
kvm_invalidate_memslot(kvm, old, invalid_slot);
}
r = kvm_prepare_memory_region(kvm, old, new, change);
if (r) {
/*
* For DELETE/MOVE, revert the above INVALID change. No
* modifications required since the original slot was preserved
* in the inactive slots. Changing the active memslots also
* release slots_arch_lock.
*/
if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) {
kvm_activate_memslot(kvm, invalid_slot, old);
kfree(invalid_slot);
} else {
mutex_unlock(&kvm->slots_arch_lock);
}
return r;
}
/*
* For DELETE and MOVE, the working slot is now active as the INVALID
* version of the old slot. MOVE is particularly special as it reuses
* the old slot and returns a copy of the old slot (in working_slot).
* For CREATE, there is no old slot. For DELETE and FLAGS_ONLY, the
* old slot is detached but otherwise preserved.
*/
if (change == KVM_MR_CREATE)
kvm_create_memslot(kvm, new);
else if (change == KVM_MR_DELETE)
kvm_delete_memslot(kvm, old, invalid_slot);
else if (change == KVM_MR_MOVE)
kvm_move_memslot(kvm, old, new, invalid_slot);
else if (change == KVM_MR_FLAGS_ONLY)
kvm_update_flags_memslot(kvm, old, new);
else
BUG();
/* Free the temporary INVALID slot used for DELETE and MOVE. */
if (change == KVM_MR_DELETE || change == KVM_MR_MOVE)
kfree(invalid_slot);
/*
* No need to refresh new->arch, changes after dropping slots_arch_lock
* will directly hit the final, active memsot. Architectures are
* responsible for knowing that new->arch may be stale.
*/
kvm_commit_memory_region(kvm, old, new, change);
return 0;
}
static bool kvm_check_memslot_overlap(struct kvm_memslots *slots, int id,
gfn_t start, gfn_t end)
{
struct kvm_memslot_iter iter;
kvm_for_each_memslot_in_gfn_range(&iter, slots, start, end) {
if (iter.slot->id != id)
return true;
}
return false;
}
/*
* Allocate some memory and give it an address in the guest physical address
* space.
*
* Discontiguous memory is allowed, mostly for framebuffers.
*
* Must be called holding kvm->slots_lock for write.
*/
int __kvm_set_memory_region(struct kvm *kvm,
const struct kvm_userspace_memory_region *mem)
{
struct kvm_memory_slot *old, *new;
struct kvm_memslots *slots;
enum kvm_mr_change change;
unsigned long npages;
gfn_t base_gfn;
int as_id, id;
int r;
r = check_memory_region_flags(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;
if ((mem->memory_size >> PAGE_SHIFT) > KVM_MEM_MAX_NR_PAGES)
return -EINVAL;
slots = __kvm_memslots(kvm, as_id);
/*
* Note, the old memslot (and the pointer itself!) may be invalidated
* and/or destroyed by kvm_set_memslot().
*/
old = id_to_memslot(slots, id);
if (!mem->memory_size) {
if (!old || !old->npages)
return -EINVAL;
if (WARN_ON_ONCE(kvm->nr_memslot_pages < old->npages))
return -EIO;
return kvm_set_memslot(kvm, old, NULL, KVM_MR_DELETE);
}
base_gfn = (mem->guest_phys_addr >> PAGE_SHIFT);
npages = (mem->memory_size >> PAGE_SHIFT);
if (!old || !old->npages) {
change = KVM_MR_CREATE;
/*
* To simplify KVM internals, the total number of pages across
* all memslots must fit in an unsigned long.
*/
if ((kvm->nr_memslot_pages + npages) < kvm->nr_memslot_pages)
return -EINVAL;
} else { /* Modify an existing slot. */
if ((mem->userspace_addr != old->userspace_addr) ||
(npages != old->npages) ||
((mem->flags ^ old->flags) & KVM_MEM_READONLY))
return -EINVAL;
if (base_gfn != old->base_gfn)
change = KVM_MR_MOVE;
else if (mem->flags != old->flags)
change = KVM_MR_FLAGS_ONLY;
else /* Nothing to change. */
return 0;
}
if ((change == KVM_MR_CREATE || change == KVM_MR_MOVE) &&
kvm_check_memslot_overlap(slots, id, base_gfn, base_gfn + npages))
return -EEXIST;
/* Allocate a slot that will persist in the memslot. */
new = kzalloc(sizeof(*new), GFP_KERNEL_ACCOUNT);
if (!new)
return -ENOMEM;
new->as_id = as_id;
new->id = id;
new->base_gfn = base_gfn;
new->npages = npages;
new->flags = mem->flags;
new->userspace_addr = mem->userspace_addr;
r = kvm_set_memslot(kvm, old, new, change);
if (r)
kfree(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)
{
struct kvm_memslots *slots = kvm_vcpu_memslots(vcpu);
u64 gen = slots->generation;
struct kvm_memory_slot *slot;
/*
* This also protects against using a memslot from a different address space,
* since different address spaces have different generation numbers.
*/
if (unlikely(gen != vcpu->last_used_slot_gen)) {
vcpu->last_used_slot = NULL;
vcpu->last_used_slot_gen = gen;
}
slot = try_get_memslot(vcpu->last_used_slot, gfn);
if (slot)
return slot;
/*
* Fall back to searching all memslots. We purposely use
* search_memslots() instead of __gfn_to_memslot() to avoid
* thrashing the VM-wide last_used_slot in kvm_memslots.
*/
slot = search_memslots(slots, gfn, false);
if (slot) {
vcpu->last_used_slot = slot;
return slot;
}
return NULL;
}
bool kvm_is_visible_gfn(struct kvm *kvm, gfn_t gfn)
{
struct kvm_memory_slot *memslot = gfn_to_memslot(kvm, gfn);
return kvm_is_visible_memslot(memslot);
}
EXPORT_SYMBOL_GPL(kvm_is_visible_gfn);
bool kvm_vcpu_is_visible_gfn(struct kvm_vcpu *vcpu, gfn_t gfn)
{
struct kvm_memory_slot *memslot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
return kvm_is_visible_memslot(memslot);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_is_visible_gfn);
unsigned long kvm_host_page_size(struct kvm_vcpu *vcpu, gfn_t gfn)
{
struct vm_area_struct *vma;
unsigned long addr, size;
size = PAGE_SIZE;
addr = kvm_vcpu_gfn_to_hva_prot(vcpu, gfn, NULL);
if (kvm_is_error_hva(addr))
return PAGE_SIZE;
mmap_read_lock(current->mm);
vma = find_vma(current->mm, addr);
if (!vma)
goto out;
size = vma_kernel_pagesize(vma);
out:
mmap_read_unlock(current->mm);
return size;
}
static bool memslot_is_readonly(const struct kvm_memory_slot *slot)
{
return slot->flags & KVM_MEM_READONLY;
}
static unsigned long __gfn_to_hva_many(const struct kvm_memory_slot *slot, gfn_t gfn,
gfn_t *nr_pages, bool write)
{
if (!slot || slot->flags & KVM_MEMSLOT_INVALID)
return KVM_HVA_ERR_BAD;
if (memslot_is_readonly(slot) && write)
return KVM_HVA_ERR_RO_BAD;
if (nr_pages)
*nr_pages = slot->npages - (gfn - slot->base_gfn);
return __gfn_to_hva_memslot(slot, gfn);
}
static unsigned long gfn_to_hva_many(struct kvm_memory_slot *slot, gfn_t gfn,
gfn_t *nr_pages)
{
return __gfn_to_hva_many(slot, gfn, nr_pages, true);
}
unsigned long gfn_to_hva_memslot(struct kvm_memory_slot *slot,
gfn_t gfn)
{
return gfn_to_hva_many(slot, gfn, NULL);
}
EXPORT_SYMBOL_GPL(gfn_to_hva_memslot);
unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
{
return gfn_to_hva_many(gfn_to_memslot(kvm, gfn), gfn, NULL);
}
EXPORT_SYMBOL_GPL(gfn_to_hva);
unsigned long kvm_vcpu_gfn_to_hva(struct kvm_vcpu *vcpu, gfn_t gfn)
{
return gfn_to_hva_many(kvm_vcpu_gfn_to_memslot(vcpu, gfn), gfn, NULL);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_gfn_to_hva);
/*
* Return the hva of a @gfn and the R/W attribute if possible.
*
* @slot: the kvm_memory_slot which contains @gfn
* @gfn: the gfn to be translated
* @writable: used to return the read/write attribute of the @slot if the hva
* is valid and @writable is not NULL
*/
unsigned long gfn_to_hva_memslot_prot(struct kvm_memory_slot *slot,
gfn_t gfn, bool *writable)
{
unsigned long hva = __gfn_to_hva_many(slot, gfn, NULL, false);
if (!kvm_is_error_hva(hva) && writable)
*writable = !memslot_is_readonly(slot);
return hva;
}
unsigned long gfn_to_hva_prot(struct kvm *kvm, gfn_t gfn, bool *writable)
{
struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
return gfn_to_hva_memslot_prot(slot, gfn, writable);
}
unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *writable)
{
struct kvm_memory_slot *slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
return gfn_to_hva_memslot_prot(slot, gfn, writable);
}
static inline int check_user_page_hwpoison(unsigned long addr)
{
int rc, flags = FOLL_HWPOISON | FOLL_WRITE;
rc = get_user_pages(addr, 1, flags, NULL, 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 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_try_get_pfn/kvm_release_pfn_clean pair will
* simply do nothing for reserved pfns.
*
* Whoever called remap_pfn_range is also going to call e.g.
* unmap_mapping_range before the underlying pages are freed,
* causing a call to our MMU notifier.
*
* Certain IO or PFNMAP mappings can be backed with valid
* struct pages, but be allocated without refcounting e.g.,
* tail pages of non-compound higher order allocations, which
* would then underflow the refcount when the caller does the
* required put_page. Don't allow those pages here.
*/
if (!kvm_try_get_pfn(pfn))
r = -EFAULT;
out:
pte_unmap_unlock(ptep, ptl);
*p_pfn = pfn;
return r;
}
/*
* Pin guest page in memory and return its pfn.
* @addr: host virtual address which maps memory to the guest
* @atomic: whether this function can sleep
* @async: whether this function need to wait IO complete if the
* host page is not in the memory
* @write_fault: whether we should get a writable host page
* @writable: whether it allows to map a writable host page for !@write_fault
*
* The function will map a writable host page for these two cases:
* 1): @write_fault = true
* 2): @write_fault = false && @writable, @writable will tell the caller
* whether the mapping is writable.
*/
kvm_pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
bool write_fault, bool *writable)
{
struct vm_area_struct *vma;
kvm_pfn_t pfn = 0;
int npages, r;
/* we can do it either atomically or asynchronously, not both */
BUG_ON(atomic && async);
if (hva_to_pfn_fast(addr, write_fault, writable, &pfn))
return pfn;
if (atomic)
return KVM_PFN_ERR_FAULT;
npages = hva_to_pfn_slow(addr, async, write_fault, writable, &pfn);
if (npages == 1)
return pfn;
mmap_read_lock(current->mm);
if (npages == -EHWPOISON ||
(!async && check_user_page_hwpoison(addr))) {
pfn = KVM_PFN_ERR_HWPOISON;
goto exit;
}
retry:
vma = vma_lookup(current->mm, addr);
if (vma == NULL)
pfn = KVM_PFN_ERR_FAULT;
else if (vma->vm_flags & (VM_IO | VM_PFNMAP)) {
r = hva_to_pfn_remapped(vma, addr, write_fault, writable, &pfn);
if (r == -EAGAIN)
goto retry;
if (r < 0)
pfn = KVM_PFN_ERR_FAULT;
} else {
if (async && vma_is_valid(vma, write_fault))
*async = true;
pfn = KVM_PFN_ERR_FAULT;
}
exit:
mmap_read_unlock(current->mm);
return pfn;
}
kvm_pfn_t __gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn,
bool atomic, bool *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(const 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(const 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)
{
if (pfn == 0)
return;
if (dirty)
kvm_release_pfn_dirty(pfn);
else
kvm_release_pfn_clean(pfn);
}
int kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map)
{
kvm_pfn_t pfn;
void *hva = NULL;
struct page *page = KVM_UNMAPPED_PAGE;
if (!map)
return -EINVAL;
pfn = gfn_to_pfn(vcpu->kvm, gfn);
if (is_error_noslot_pfn(pfn))
return -EINVAL;
if (pfn_valid(pfn)) {
page = pfn_to_page(pfn);
hva = kmap(page);
#ifdef CONFIG_HAS_IOMEM
} else {
hva = memremap(pfn_to_hpa(pfn), PAGE_SIZE, MEMREMAP_WB);
#endif
}
if (!hva)
return -EFAULT;
map->page = page;
map->hva = hva;
map->pfn = pfn;
map->gfn = gfn;
return 0;
}
EXPORT_SYMBOL_GPL(kvm_vcpu_map);
void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map, bool dirty)
{
if (!map)
return;
if (!map->hva)
return;
if (map->page != KVM_UNMAPPED_PAGE)
kunmap(map->page);
#ifdef CONFIG_HAS_IOMEM
else
memunmap(map->hva);
#endif
if (dirty)
kvm_vcpu_mark_page_dirty(vcpu, map->gfn);
kvm_release_pfn(map->pfn, dirty);
map->hva = NULL;
map->page = NULL;
}
EXPORT_SYMBOL_GPL(kvm_vcpu_unmap);
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);
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