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kernel / pub / scm / linux / kernel / git / stable / linux-stable-rc / ae13bd23102805383bf04f26e0b043f3d02c9b15 / . / virt / kvm / kvm_main.c
blob: 226faeaa8e5692c5a889f5a9345f756c9846ba6c [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* Kernel-based Virtual Machine (KVM) Hypervisor
*
* Copyright (C) 2006 Qumranet, Inc.
* Copyright 2010 Red Hat, Inc. and/or its affiliates.
*
* Authors:
* Avi Kivity <avi@qumranet.com>
* Yaniv Kamay <yaniv@qumranet.com>
*/
#include <kvm/iodev.h>
#include <linux/kvm_host.h>
#include <linux/kvm.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/percpu.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/vmalloc.h>
#include <linux/reboot.h>
#include <linux/debugfs.h>
#include <linux/highmem.h>
#include <linux/file.h>
#include <linux/syscore_ops.h>
#include <linux/cpu.h>
#include <linux/sched/signal.h>
#include <linux/sched/mm.h>
#include <linux/sched/stat.h>
#include <linux/cpumask.h>
#include <linux/smp.h>
#include <linux/anon_inodes.h>
#include <linux/profile.h>
#include <linux/kvm_para.h>
#include <linux/pagemap.h>
#include <linux/mman.h>
#include <linux/swap.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/compat.h>
#include <linux/srcu.h>
#include <linux/hugetlb.h>
#include <linux/slab.h>
#include <linux/sort.h>
#include <linux/bsearch.h>
#include <linux/io.h>
#include <linux/lockdep.h>
#include <linux/kthread.h>
#include <linux/suspend.h>
#include <asm/processor.h>
#include <asm/ioctl.h>
#include <linux/uaccess.h>
#include "coalesced_mmio.h"
#include "async_pf.h"
#include "kvm_mm.h"
#include "vfio.h"
#include <trace/events/ipi.h>
#define CREATE_TRACE_POINTS
#include <trace/events/kvm.h>
#include <linux/kvm_dirty_ring.h>
/* Worst case buffer size needed for holding an integer. */
#define ITOA_MAX_LEN 12
MODULE_AUTHOR("Qumranet");
MODULE_DESCRIPTION("Kernel-based Virtual Machine (KVM) Hypervisor");
MODULE_LICENSE("GPL");
/* Architectures should define their poll value according to the halt latency */
unsigned int halt_poll_ns = KVM_HALT_POLL_NS_DEFAULT;
module_param(halt_poll_ns, uint, 0644);
EXPORT_SYMBOL_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(halt_poll_ns_grow_start);
/* Default halves per-vcpu halt_poll_ns. */
unsigned int halt_poll_ns_shrink = 2;
module_param(halt_poll_ns_shrink, uint, 0644);
EXPORT_SYMBOL_FOR_KVM_INTERNAL(halt_poll_ns_shrink);
/*
* Allow direct access (from KVM or the CPU) without MMU notifier protection
* to unpinned pages.
*/
static bool allow_unsafe_mappings;
module_param(allow_unsafe_mappings, bool, 0444);
/*
* Ordering of locks:
*
* kvm->lock --> kvm->slots_lock --> kvm->irq_lock
*/
DEFINE_MUTEX(kvm_lock);
LIST_HEAD(vm_list);
static struct kmem_cache *kvm_vcpu_cache;
static __read_mostly struct preempt_ops kvm_preempt_ops;
static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_running_vcpu);
static struct dentry *kvm_debugfs_dir;
static const struct file_operations stat_fops_per_vm;
static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
unsigned long arg);
#ifdef CONFIG_KVM_COMPAT
static long kvm_vcpu_compat_ioctl(struct file *file, unsigned int ioctl,
unsigned long arg);
#define KVM_COMPAT(c) .compat_ioctl = (c)
#else
/*
* For architectures that don't implement a compat infrastructure,
* adopt a double line of defense:
* - Prevent a compat task from opening /dev/kvm
* - If the open has been done by a 64bit task, and the KVM fd
* passed to a compat task, let the ioctls fail.
*/
static long kvm_no_compat_ioctl(struct file *file, unsigned int ioctl,
unsigned long arg) { return -EINVAL; }
static int kvm_no_compat_open(struct inode *inode, struct file *file)
{
return is_compat_task() ? -ENODEV : 0;
}
#define KVM_COMPAT(c) .compat_ioctl = kvm_no_compat_ioctl, \
.open = kvm_no_compat_open
#endif
static void kvm_io_bus_destroy(struct kvm_io_bus *bus);
#define KVM_EVENT_CREATE_VM 0
#define KVM_EVENT_DESTROY_VM 1
static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm);
static unsigned long long kvm_createvm_count;
static unsigned long long kvm_active_vms;
static DEFINE_PER_CPU(cpumask_var_t, cpu_kick_mask);
__weak void kvm_arch_guest_memory_reclaimed(struct kvm *kvm)
{
}
/*
* 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_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(vcpu_put);
/* TODO: merge with kvm_arch_vcpu_should_kick */
static bool kvm_request_needs_ipi(struct kvm_vcpu *vcpu, unsigned req)
{
int mode = kvm_vcpu_exiting_guest_mode(vcpu);
/*
* We need to wait for the VCPU to reenable interrupts and get out of
* READING_SHADOW_PAGE_TABLES mode.
*/
if (req & KVM_REQUEST_WAIT)
return mode != OUTSIDE_GUEST_MODE;
/*
* Need to kick a running VCPU, but otherwise there is nothing to do.
*/
return mode == IN_GUEST_MODE;
}
static void ack_kick(void *_completed)
{
}
static inline bool kvm_kick_many_cpus(struct cpumask *cpus, bool wait)
{
if (cpumask_empty(cpus))
return false;
smp_call_function_many(cpus, ack_kick, NULL, wait);
return true;
}
static void kvm_make_vcpu_request(struct kvm_vcpu *vcpu, unsigned int req,
struct cpumask *tmp, int current_cpu)
{
int cpu;
if (likely(!(req & KVM_REQUEST_NO_ACTION)))
__kvm_make_request(req, vcpu);
if (!(req & KVM_REQUEST_NO_WAKEUP) && kvm_vcpu_wake_up(vcpu))
return;
/*
* Note, the vCPU could get migrated to a different pCPU at any point
* after kvm_request_needs_ipi(), which could result in sending an IPI
* to the previous pCPU. But, that's OK because the purpose of the IPI
* is to ensure the vCPU returns to OUTSIDE_GUEST_MODE, which is
* satisfied if the vCPU migrates. Entering READING_SHADOW_PAGE_TABLES
* after this point is also OK, as the requirement is only that KVM wait
* for vCPUs that were reading SPTEs _before_ any changes were
* finalized. See kvm_vcpu_kick() for more details on handling requests.
*/
if (kvm_request_needs_ipi(vcpu, req)) {
cpu = READ_ONCE(vcpu->cpu);
if (cpu != -1 && cpu != current_cpu)
__cpumask_set_cpu(cpu, tmp);
}
}
bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
unsigned long *vcpu_bitmap)
{
struct kvm_vcpu *vcpu;
struct cpumask *cpus;
int i, me;
bool called;
me = get_cpu();
cpus = this_cpu_cpumask_var_ptr(cpu_kick_mask);
cpumask_clear(cpus);
for_each_set_bit(i, vcpu_bitmap, KVM_MAX_VCPUS) {
vcpu = kvm_get_vcpu(kvm, i);
if (!vcpu)
continue;
kvm_make_vcpu_request(vcpu, req, cpus, me);
}
called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT));
put_cpu();
return called;
}
bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
{
struct kvm_vcpu *vcpu;
struct cpumask *cpus;
unsigned long i;
bool called;
int me;
me = get_cpu();
cpus = this_cpu_cpumask_var_ptr(cpu_kick_mask);
cpumask_clear(cpus);
kvm_for_each_vcpu(i, vcpu, kvm)
kvm_make_vcpu_request(vcpu, req, cpus, me);
called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT));
put_cpu();
return called;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_make_all_cpus_request);
void kvm_flush_remote_tlbs(struct kvm *kvm)
{
++kvm->stat.generic.remote_tlb_flush_requests;
/*
* We want to publish modifications to the page tables before reading
* mode. Pairs with a memory barrier in arch-specific code.
* - x86: smp_mb__after_srcu_read_unlock in vcpu_enter_guest
* and smp_mb in walk_shadow_page_lockless_begin/end.
* - powerpc: smp_mb in kvmppc_prepare_to_enter.
*
* There is already an smp_mb__after_atomic() before
* kvm_make_all_cpus_request() reads vcpu->mode. We reuse that
* barrier here.
*/
if (!kvm_arch_flush_remote_tlbs(kvm)
|| kvm_make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH))
++kvm->stat.generic.remote_tlb_flush;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_flush_remote_tlbs);
void kvm_flush_remote_tlbs_range(struct kvm *kvm, gfn_t gfn, u64 nr_pages)
{
if (!kvm_arch_flush_remote_tlbs_range(kvm, gfn, nr_pages))
return;
/*
* Fall back to a flushing entire TLBs if the architecture range-based
* TLB invalidation is unsupported or can't be performed for whatever
* reason.
*/
kvm_flush_remote_tlbs(kvm);
}
void kvm_flush_remote_tlbs_memslot(struct kvm *kvm,
const struct kvm_memory_slot *memslot)
{
/*
* All current use cases for flushing the TLBs for a specific memslot
* are related to dirty logging, and many do the TLB flush out of
* mmu_lock. The interaction between the various operations on memslot
* must be serialized by slots_lock to ensure the TLB flush from one
* operation is observed by any other operation on the same memslot.
*/
lockdep_assert_held(&kvm->slots_lock);
kvm_flush_remote_tlbs_range(kvm, memslot->base_gfn, memslot->npages);
}
static void kvm_flush_shadow_all(struct kvm *kvm)
{
kvm_arch_flush_shadow_all(kvm);
kvm_arch_guest_memory_reclaimed(kvm);
}
#ifdef KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE
static inline void *mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache *mc,
gfp_t gfp_flags)
{
void *page;
gfp_flags |= mc->gfp_zero;
if (mc->kmem_cache)
return kmem_cache_alloc(mc->kmem_cache, gfp_flags);
page = (void *)__get_free_page(gfp_flags);
if (page && mc->init_value)
memset64(page, mc->init_value, PAGE_SIZE / sizeof(u64));
return page;
}
int __kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int capacity, int min)
{
gfp_t gfp = mc->gfp_custom ? mc->gfp_custom : GFP_KERNEL_ACCOUNT;
void *obj;
if (mc->nobjs >= min)
return 0;
if (unlikely(!mc->objects)) {
if (WARN_ON_ONCE(!capacity))
return -EIO;
/*
* Custom init values can be used only for page allocations,
* and obviously conflict with __GFP_ZERO.
*/
if (WARN_ON_ONCE(mc->init_value && (mc->kmem_cache || mc->gfp_zero)))
return -EIO;
mc->objects = kvmalloc_array(capacity, sizeof(void *), gfp);
if (!mc->objects)
return -ENOMEM;
mc->capacity = capacity;
}
/* It is illegal to request a different capacity across topups. */
if (WARN_ON_ONCE(mc->capacity != capacity))
return -EIO;
while (mc->nobjs < mc->capacity) {
obj = mmu_memory_cache_alloc_obj(mc, gfp);
if (!obj)
return mc->nobjs >= min ? 0 : -ENOMEM;
mc->objects[mc->nobjs++] = obj;
}
return 0;
}
int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min)
{
return __kvm_mmu_topup_memory_cache(mc, KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE, min);
}
int kvm_mmu_memory_cache_nr_free_objects(struct kvm_mmu_memory_cache *mc)
{
return mc->nobjs;
}
void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
{
while (mc->nobjs) {
if (mc->kmem_cache)
kmem_cache_free(mc->kmem_cache, mc->objects[--mc->nobjs]);
else
free_page((unsigned long)mc->objects[--mc->nobjs]);
}
kvfree(mc->objects);
mc->objects = NULL;
mc->capacity = 0;
}
void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
{
void *p;
if (WARN_ON(!mc->nobjs))
p = mmu_memory_cache_alloc_obj(mc, GFP_ATOMIC | __GFP_ACCOUNT);
else
p = mc->objects[--mc->nobjs];
BUG_ON(!p);
return p;
}
#endif
static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
{
mutex_init(&vcpu->mutex);
vcpu->cpu = -1;
vcpu->kvm = kvm;
vcpu->vcpu_id = id;
vcpu->pid = NULL;
rwlock_init(&vcpu->pid_lock);
#ifndef __KVM_HAVE_ARCH_WQP
rcuwait_init(&vcpu->wait);
#endif
kvm_async_pf_vcpu_init(vcpu);
kvm_vcpu_set_in_spin_loop(vcpu, false);
kvm_vcpu_set_dy_eligible(vcpu, false);
vcpu->preempted = false;
vcpu->ready = false;
preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops);
vcpu->last_used_slot = NULL;
/* Fill the stats id string for the vcpu */
snprintf(vcpu->stats_id, sizeof(vcpu->stats_id), "kvm-%d/vcpu-%d",
task_pid_nr(current), id);
}
static void kvm_vcpu_destroy(struct kvm_vcpu *vcpu)
{
kvm_arch_vcpu_destroy(vcpu);
kvm_dirty_ring_free(&vcpu->dirty_ring);
/*
* No need for rcu_read_lock as VCPU_RUN is the only place that changes
* the vcpu->pid pointer, and at destruction time all file descriptors
* are already gone.
*/
put_pid(vcpu->pid);
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);
/*
* Assert that the vCPU isn't visible in any way, to ensure KVM
* doesn't trigger a use-after-free if destroying vCPUs results
* in VM-wide request, e.g. to flush remote TLBs when tearing
* down MMUs, or to mark the VM dead if a KVM_BUG_ON() fires.
*/
WARN_ON_ONCE(xa_load(&kvm->vcpu_array, i) || kvm_get_vcpu(kvm, i));
}
atomic_set(&kvm->online_vcpus, 0);
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_destroy_vcpus);
#ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER
static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn)
{
return container_of(mn, struct kvm, mmu_notifier);
}
typedef bool (*gfn_handler_t)(struct kvm *kvm, struct kvm_gfn_range *range);
typedef void (*on_lock_fn_t)(struct kvm *kvm);
struct kvm_mmu_notifier_range {
/*
* 64-bit addresses, as KVM notifiers can operate on host virtual
* addresses (unsigned long) and guest physical addresses (64-bit).
*/
u64 start;
u64 end;
union kvm_mmu_notifier_arg arg;
gfn_handler_t handler;
on_lock_fn_t on_lock;
bool flush_on_ret;
bool may_block;
bool lockless;
};
/*
* The inner-most helper returns a tuple containing the return value from the
* arch- and action-specific handler, plus a flag indicating whether or not at
* least one memslot was found, i.e. if the handler found guest memory.
*
* Note, most notifiers are averse to booleans, so even though KVM tracks the
* return from arch code as a bool, outer helpers will cast it to an int. :-(
*/
typedef struct kvm_mmu_notifier_return {
bool ret;
bool found_memslot;
} kvm_mn_ret_t;
/*
* Use a dedicated stub instead of NULL to indicate that there is no callback
* function/handler. The compiler technically can't guarantee that a real
* function will have a non-zero address, and so it will generate code to
* check for !NULL, whereas comparing against a stub will be elided at compile
* time (unless the compiler is getting long in the tooth, e.g. gcc 4.9).
*/
static void kvm_null_fn(void)
{
}
#define IS_KVM_NULL_FN(fn) ((fn) == (void *)kvm_null_fn)
/* Iterate over each memslot intersecting [start, last] (inclusive) range */
#define kvm_for_each_memslot_in_hva_range(node, slots, start, last) \
for (node = interval_tree_iter_first(&slots->hva_tree, start, last); \
node; \
node = interval_tree_iter_next(node, start, last)) \
static __always_inline kvm_mn_ret_t kvm_handle_hva_range(struct kvm *kvm,
const struct kvm_mmu_notifier_range *range)
{
struct kvm_mmu_notifier_return r = {
.ret = false,
.found_memslot = false,
};
struct kvm_gfn_range gfn_range;
struct kvm_memory_slot *slot;
struct kvm_memslots *slots;
int i, idx;
if (WARN_ON_ONCE(range->end <= range->start))
return r;
/* A null handler is allowed if and only if on_lock() is provided. */
if (WARN_ON_ONCE(IS_KVM_NULL_FN(range->on_lock) &&
IS_KVM_NULL_FN(range->handler)))
return r;
/* on_lock will never be called for lockless walks */
if (WARN_ON_ONCE(range->lockless && !IS_KVM_NULL_FN(range->on_lock)))
return r;
idx = srcu_read_lock(&kvm->srcu);
for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
struct interval_tree_node *node;
slots = __kvm_memslots(kvm, i);
kvm_for_each_memslot_in_hva_range(node, slots,
range->start, range->end - 1) {
unsigned long hva_start, hva_end;
slot = container_of(node, struct kvm_memory_slot, hva_node[slots->node_idx]);
hva_start = max_t(unsigned long, range->start, slot->userspace_addr);
hva_end = min_t(unsigned long, range->end,
slot->userspace_addr + (slot->npages << PAGE_SHIFT));
/*
* To optimize for the likely case where the address
* range is covered by zero or one memslots, don't
* bother making these conditional (to avoid writes on
* the second or later invocation of the handler).
*/
gfn_range.arg = range->arg;
gfn_range.may_block = range->may_block;
/*
* HVA-based notifications aren't relevant to private
* mappings as they don't have a userspace mapping.
*/
gfn_range.attr_filter = KVM_FILTER_SHARED;
/*
* {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;
gfn_range.lockless = range->lockless;
if (!r.found_memslot) {
r.found_memslot = true;
if (!range->lockless) {
KVM_MMU_LOCK(kvm);
if (!IS_KVM_NULL_FN(range->on_lock))
range->on_lock(kvm);
if (IS_KVM_NULL_FN(range->handler))
goto mmu_unlock;
}
}
r.ret |= range->handler(kvm, &gfn_range);
}
}
if (range->flush_on_ret && r.ret)
kvm_flush_remote_tlbs(kvm);
mmu_unlock:
if (r.found_memslot && !range->lockless)
KVM_MMU_UNLOCK(kvm);
srcu_read_unlock(&kvm->srcu, idx);
return r;
}
static __always_inline int kvm_age_hva_range(struct mmu_notifier *mn,
unsigned long start,
unsigned long end,
gfn_handler_t handler,
bool flush_on_ret)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
const struct kvm_mmu_notifier_range range = {
.start = start,
.end = end,
.handler = handler,
.on_lock = (void *)kvm_null_fn,
.flush_on_ret = flush_on_ret,
.may_block = false,
.lockless = IS_ENABLED(CONFIG_KVM_MMU_LOCKLESS_AGING),
};
return kvm_handle_hva_range(kvm, &range).ret;
}
static __always_inline int kvm_age_hva_range_no_flush(struct mmu_notifier *mn,
unsigned long start,
unsigned long end,
gfn_handler_t handler)
{
return kvm_age_hva_range(mn, start, end, handler, false);
}
void kvm_mmu_invalidate_begin(struct kvm *kvm)
{
lockdep_assert_held_write(&kvm->mmu_lock);
/*
* The count increase must become visible at unlock time as no
* spte can be established without taking the mmu_lock and
* count is also read inside the mmu_lock critical section.
*/
kvm->mmu_invalidate_in_progress++;
if (likely(kvm->mmu_invalidate_in_progress == 1)) {
kvm->mmu_invalidate_range_start = INVALID_GPA;
kvm->mmu_invalidate_range_end = INVALID_GPA;
}
}
void kvm_mmu_invalidate_range_add(struct kvm *kvm, gfn_t start, gfn_t end)
{
lockdep_assert_held_write(&kvm->mmu_lock);
WARN_ON_ONCE(!kvm->mmu_invalidate_in_progress);
if (likely(kvm->mmu_invalidate_range_start == INVALID_GPA)) {
kvm->mmu_invalidate_range_start = start;
kvm->mmu_invalidate_range_end = end;
} else {
/*
* Fully tracking multiple concurrent ranges has diminishing
* returns. Keep things simple and just find the minimal range
* which includes the current and new ranges. As there won't be
* enough information to subtract a range after its invalidate
* completes, any ranges invalidated concurrently will
* accumulate and persist until all outstanding invalidates
* complete.
*/
kvm->mmu_invalidate_range_start =
min(kvm->mmu_invalidate_range_start, start);
kvm->mmu_invalidate_range_end =
max(kvm->mmu_invalidate_range_end, end);
}
}
bool kvm_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
{
kvm_mmu_invalidate_range_add(kvm, range->start, range->end);
return kvm_unmap_gfn_range(kvm, range);
}
static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
const struct mmu_notifier_range *range)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
const struct kvm_mmu_notifier_range hva_range = {
.start = range->start,
.end = range->end,
.handler = kvm_mmu_unmap_gfn_range,
.on_lock = kvm_mmu_invalidate_begin,
.flush_on_ret = true,
.may_block = mmu_notifier_range_blockable(range),
};
trace_kvm_unmap_hva_range(range->start, range->end);
/*
* Prevent memslot modification between range_start() and range_end()
* so that conditionally locking provides the same result in both
* functions. Without that guarantee, the mmu_invalidate_in_progress
* adjustments will be imbalanced.
*
* Pairs with the decrement in range_end().
*/
spin_lock(&kvm->mn_invalidate_lock);
kvm->mn_active_invalidate_count++;
spin_unlock(&kvm->mn_invalidate_lock);
/*
* Invalidate pfn caches _before_ invalidating the secondary MMUs, i.e.
* before acquiring mmu_lock, to avoid holding mmu_lock while acquiring
* each cache's lock. There are relatively few caches in existence at
* any given time, and the caches themselves can check for hva overlap,
* i.e. don't need to rely on memslot overlap checks for performance.
* Because this runs without holding mmu_lock, the pfn caches must use
* mn_active_invalidate_count (see above) instead of
* mmu_invalidate_in_progress.
*/
gfn_to_pfn_cache_invalidate_start(kvm, range->start, range->end);
/*
* If one or more memslots were found and thus zapped, notify arch code
* that guest memory has been reclaimed. This needs to be done *after*
* dropping mmu_lock, as x86's reclaim path is slooooow.
*/
if (kvm_handle_hva_range(kvm, &hva_range).found_memslot)
kvm_arch_guest_memory_reclaimed(kvm);
return 0;
}
void kvm_mmu_invalidate_end(struct kvm *kvm)
{
lockdep_assert_held_write(&kvm->mmu_lock);
/*
* This sequence increase will notify the kvm page fault that
* the page that is going to be mapped in the spte could have
* been freed.
*/
kvm->mmu_invalidate_seq++;
smp_wmb();
/*
* The above sequence increase must be visible before the
* below count decrease, which is ensured by the smp_wmb above
* in conjunction with the smp_rmb in mmu_invalidate_retry().
*/
kvm->mmu_invalidate_in_progress--;
KVM_BUG_ON(kvm->mmu_invalidate_in_progress < 0, kvm);
/*
* Assert that at least one range was added between start() and end().
* Not adding a range isn't fatal, but it is a KVM bug.
*/
WARN_ON_ONCE(kvm->mmu_invalidate_range_start == INVALID_GPA);
}
static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,
const struct mmu_notifier_range *range)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
const struct kvm_mmu_notifier_range hva_range = {
.start = range->start,
.end = range->end,
.handler = (void *)kvm_null_fn,
.on_lock = kvm_mmu_invalidate_end,
.flush_on_ret = false,
.may_block = mmu_notifier_range_blockable(range),
};
bool wake;
kvm_handle_hva_range(kvm, &hva_range);
/* Pairs with the increment in range_start(). */
spin_lock(&kvm->mn_invalidate_lock);
if (!WARN_ON_ONCE(!kvm->mn_active_invalidate_count))
--kvm->mn_active_invalidate_count;
wake = !kvm->mn_active_invalidate_count;
spin_unlock(&kvm->mn_invalidate_lock);
/*
* There can only be one waiter, since the wait happens under
* slots_lock.
*/
if (wake)
rcuwait_wake_up(&kvm->mn_memslots_update_rcuwait);
}
static int kvm_mmu_notifier_clear_flush_young(struct mmu_notifier *mn,
struct mm_struct *mm,
unsigned long start,
unsigned long end)
{
trace_kvm_age_hva(start, end);
return kvm_age_hva_range(mn, start, end, kvm_age_gfn,
!IS_ENABLED(CONFIG_KVM_ELIDE_TLB_FLUSH_IF_YOUNG));
}
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_age_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_age_hva_range_no_flush(mn, address, address + 1,
kvm_test_age_gfn);
}
static void kvm_mmu_notifier_release(struct mmu_notifier *mn,
struct mm_struct *mm)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
int idx;
idx = srcu_read_lock(&kvm->srcu);
kvm_flush_shadow_all(kvm);
srcu_read_unlock(&kvm->srcu, idx);
}
static const struct mmu_notifier_ops kvm_mmu_notifier_ops = {
.invalidate_range_start = kvm_mmu_notifier_invalidate_range_start,
.invalidate_range_end = kvm_mmu_notifier_invalidate_range_end,
.clear_flush_young = kvm_mmu_notifier_clear_flush_young,
.clear_young = kvm_mmu_notifier_clear_young,
.test_young = kvm_mmu_notifier_test_young,
.release = kvm_mmu_notifier_release,
};
static int kvm_init_mmu_notifier(struct kvm *kvm)
{
kvm->mmu_notifier.ops = &kvm_mmu_notifier_ops;
return mmu_notifier_register(&kvm->mmu_notifier, current->mm);
}
#else /* !CONFIG_KVM_GENERIC_MMU_NOTIFIER */
static int kvm_init_mmu_notifier(struct kvm *kvm)
{
return 0;
}
#endif /* CONFIG_KVM_GENERIC_MMU_NOTIFIER */
#ifdef CONFIG_HAVE_KVM_PM_NOTIFIER
static int kvm_pm_notifier_call(struct notifier_block *bl,
unsigned long state,
void *unused)
{
struct kvm *kvm = container_of(bl, struct kvm, pm_notifier);
return kvm_arch_pm_notifier(kvm, state);
}
static void kvm_init_pm_notifier(struct kvm *kvm)
{
kvm->pm_notifier.notifier_call = kvm_pm_notifier_call;
/* Suspend KVM before we suspend ftrace, RCU, etc. */
kvm->pm_notifier.priority = INT_MAX;
register_pm_notifier(&kvm->pm_notifier);
}
static void kvm_destroy_pm_notifier(struct kvm *kvm)
{
unregister_pm_notifier(&kvm->pm_notifier);
}
#else /* !CONFIG_HAVE_KVM_PM_NOTIFIER */
static void kvm_init_pm_notifier(struct kvm *kvm)
{
}
static void kvm_destroy_pm_notifier(struct kvm *kvm)
{
}
#endif /* CONFIG_HAVE_KVM_PM_NOTIFIER */
static void kvm_destroy_dirty_bitmap(struct kvm_memory_slot *memslot)
{
if (!memslot->dirty_bitmap)
return;
vfree(memslot->dirty_bitmap);
memslot->dirty_bitmap = NULL;
}
/* This does not remove the slot from struct kvm_memslots data structures */
static void kvm_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot)
{
if (slot->flags & KVM_MEM_GUEST_MEMFD)
kvm_gmem_unbind(slot);
kvm_destroy_dirty_bitmap(slot);
kvm_arch_free_memslot(kvm, slot);
kfree(slot);
}
static void kvm_free_memslots(struct kvm *kvm, struct kvm_memslots *slots)
{
struct hlist_node *idnode;
struct kvm_memory_slot *memslot;
int bkt;
/*
* The same memslot objects live in both active and inactive sets,
* arbitrarily free using index '1' so the second invocation of this
* function isn't operating over a structure with dangling pointers
* (even though this function isn't actually touching them).
*/
if (!slots->node_idx)
return;
hash_for_each_safe(slots->id_hash, bkt, idnode, memslot, id_node[1])
kvm_free_memslot(kvm, memslot);
}
static umode_t kvm_stats_debugfs_mode(const struct _kvm_stats_desc *pdesc)
{
switch (pdesc->desc.flags & KVM_STATS_TYPE_MASK) {
case KVM_STATS_TYPE_INSTANT:
return 0444;
case KVM_STATS_TYPE_CUMULATIVE:
case KVM_STATS_TYPE_PEAK:
default:
return 0644;
}
}
static void kvm_destroy_vm_debugfs(struct kvm *kvm)
{
int i;
int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc +
kvm_vcpu_stats_header.num_desc;
if (IS_ERR(kvm->debugfs_dentry))
return;
debugfs_remove_recursive(kvm->debugfs_dentry);
if (kvm->debugfs_stat_data) {
for (i = 0; i < kvm_debugfs_num_entries; i++)
kfree(kvm->debugfs_stat_data[i]);
kfree(kvm->debugfs_stat_data);
}
}
static int kvm_create_vm_debugfs(struct kvm *kvm, const char *fdname)
{
static DEFINE_MUTEX(kvm_debugfs_lock);
struct dentry *dent;
char dir_name[ITOA_MAX_LEN * 2];
struct kvm_stat_data *stat_data;
const struct _kvm_stats_desc *pdesc;
int i, ret = -ENOMEM;
int kvm_debugfs_num_entries = kvm_vm_stats_header.num_desc +
kvm_vcpu_stats_header.num_desc;
if (!debugfs_initialized())
return 0;
snprintf(dir_name, sizeof(dir_name), "%d-%s", task_pid_nr(current), fdname);
mutex_lock(&kvm_debugfs_lock);
dent = debugfs_lookup(dir_name, kvm_debugfs_dir);
if (dent) {
pr_warn_ratelimited("KVM: debugfs: duplicate directory %s\n", dir_name);
dput(dent);
mutex_unlock(&kvm_debugfs_lock);
return 0;
}
dent = debugfs_create_dir(dir_name, kvm_debugfs_dir);
mutex_unlock(&kvm_debugfs_lock);
if (IS_ERR(dent))
return 0;
kvm->debugfs_dentry = dent;
kvm->debugfs_stat_data = kcalloc(kvm_debugfs_num_entries,
sizeof(*kvm->debugfs_stat_data),
GFP_KERNEL_ACCOUNT);
if (!kvm->debugfs_stat_data)
goto out_err;
for (i = 0; i < kvm_vm_stats_header.num_desc; ++i) {
pdesc = &kvm_vm_stats_desc[i];
stat_data = kzalloc(sizeof(*stat_data), GFP_KERNEL_ACCOUNT);
if (!stat_data)
goto out_err;
stat_data->kvm = kvm;
stat_data->desc = pdesc;
stat_data->kind = KVM_STAT_VM;
kvm->debugfs_stat_data[i] = stat_data;
debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
kvm->debugfs_dentry, stat_data,
&stat_fops_per_vm);
}
for (i = 0; i < kvm_vcpu_stats_header.num_desc; ++i) {
pdesc = &kvm_vcpu_stats_desc[i];
stat_data = kzalloc(sizeof(*stat_data), GFP_KERNEL_ACCOUNT);
if (!stat_data)
goto out_err;
stat_data->kvm = kvm;
stat_data->desc = pdesc;
stat_data->kind = KVM_STAT_VCPU;
kvm->debugfs_stat_data[i + kvm_vm_stats_header.num_desc] = stat_data;
debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
kvm->debugfs_dentry, stat_data,
&stat_fops_per_vm);
}
kvm_arch_create_vm_debugfs(kvm);
return 0;
out_err:
kvm_destroy_vm_debugfs(kvm);
return ret;
}
/*
* Called just after removing the VM from the vm_list, but before doing any
* other destruction.
*/
void __weak kvm_arch_pre_destroy_vm(struct kvm *kvm)
{
}
/*
* Called after per-vm debugfs created. When called kvm->debugfs_dentry should
* be setup already, so we can create arch-specific debugfs entries under it.
* Cleanup should be automatic done in kvm_destroy_vm_debugfs() recursively, so
* a per-arch destroy interface is not needed.
*/
void __weak kvm_arch_create_vm_debugfs(struct kvm *kvm)
{
}
/* Called only on cleanup and destruction paths when there are no users. */
static inline struct kvm_io_bus *kvm_get_bus_for_destruction(struct kvm *kvm,
enum kvm_bus idx)
{
return rcu_dereference_protected(kvm->buses[idx],
!refcount_read(&kvm->users_count));
}
static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
{
struct kvm *kvm = kvm_arch_alloc_vm();
struct kvm_memslots *slots;
int r, i, j;
if (!kvm)
return ERR_PTR(-ENOMEM);
KVM_MMU_LOCK_INIT(kvm);
mmgrab(current->mm);
kvm->mm = current->mm;
kvm_eventfd_init(kvm);
mutex_init(&kvm->lock);
mutex_init(&kvm->irq_lock);
mutex_init(&kvm->slots_lock);
mutex_init(&kvm->slots_arch_lock);
spin_lock_init(&kvm->mn_invalidate_lock);
rcuwait_init(&kvm->mn_memslots_update_rcuwait);
xa_init(&kvm->vcpu_array);
#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
xa_init(&kvm->mem_attr_array);
#endif
INIT_LIST_HEAD(&kvm->gpc_list);
spin_lock_init(&kvm->gpc_lock);
INIT_LIST_HEAD(&kvm->devices);
kvm->max_vcpus = KVM_MAX_VCPUS;
BUILD_BUG_ON(KVM_MEM_SLOTS_NUM > SHRT_MAX);
/*
* Force subsequent debugfs file creations to fail if the VM directory
* is not created (by kvm_create_vm_debugfs()).
*/
kvm->debugfs_dentry = ERR_PTR(-ENOENT);
snprintf(kvm->stats_id, sizeof(kvm->stats_id), "kvm-%d",
task_pid_nr(current));
r = -ENOMEM;
if (init_srcu_struct(&kvm->srcu))
goto out_err_no_srcu;
if (init_srcu_struct(&kvm->irq_srcu))
goto out_err_no_irq_srcu;
r = kvm_init_irq_routing(kvm);
if (r)
goto out_err_no_irq_routing;
refcount_set(&kvm->users_count, 1);
for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
for (j = 0; j < 2; j++) {
slots = &kvm->__memslots[i][j];
atomic_long_set(&slots->last_used_slot, (unsigned long)NULL);
slots->hva_tree = RB_ROOT_CACHED;
slots->gfn_tree = RB_ROOT;
hash_init(slots->id_hash);
slots->node_idx = j;
/* Generations must be different for each address space. */
slots->generation = i;
}
rcu_assign_pointer(kvm->memslots[i], &kvm->__memslots[i][0]);
}
r = -ENOMEM;
for (i = 0; i < KVM_NR_BUSES; i++) {
rcu_assign_pointer(kvm->buses[i],
kzalloc(sizeof(struct kvm_io_bus), GFP_KERNEL_ACCOUNT));
if (!kvm->buses[i])
goto out_err_no_arch_destroy_vm;
}
r = kvm_arch_init_vm(kvm, type);
if (r)
goto out_err_no_arch_destroy_vm;
r = kvm_enable_virtualization();
if (r)
goto out_err_no_disable;
#ifdef CONFIG_HAVE_KVM_IRQCHIP
INIT_HLIST_HEAD(&kvm->irq_ack_notifier_list);
#endif
r = kvm_init_mmu_notifier(kvm);
if (r)
goto out_err_no_mmu_notifier;
r = kvm_coalesced_mmio_init(kvm);
if (r < 0)
goto out_no_coalesced_mmio;
r = kvm_create_vm_debugfs(kvm, fdname);
if (r)
goto out_err_no_debugfs;
mutex_lock(&kvm_lock);
list_add(&kvm->vm_list, &vm_list);
mutex_unlock(&kvm_lock);
preempt_notifier_inc();
kvm_init_pm_notifier(kvm);
return kvm;
out_err_no_debugfs:
kvm_coalesced_mmio_free(kvm);
out_no_coalesced_mmio:
#ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER
if (kvm->mmu_notifier.ops)
mmu_notifier_unregister(&kvm->mmu_notifier, current->mm);
#endif
out_err_no_mmu_notifier:
kvm_disable_virtualization();
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_for_destruction(kvm, i));
kvm_free_irq_routing(kvm);
out_err_no_irq_routing:
cleanup_srcu_struct(&kvm->irq_srcu);
out_err_no_irq_srcu:
cleanup_srcu_struct(&kvm->srcu);
out_err_no_srcu:
kvm_arch_free_vm(kvm);
mmdrop(current->mm);
return ERR_PTR(r);
}
static void kvm_destroy_devices(struct kvm *kvm)
{
struct kvm_device *dev, *tmp;
/*
* We do not need to take the kvm->lock here, because nobody else
* has a reference to the struct kvm at this point and therefore
* cannot access the devices list anyhow.
*
* The device list is generally managed as an rculist, but list_del()
* is used intentionally here. If a bug in KVM introduced a reader that
* was not backed by a reference on the kvm struct, the hope is that
* it'd consume the poisoned forward pointer instead of suffering a
* use-after-free, even though this cannot be guaranteed.
*/
list_for_each_entry_safe(dev, tmp, &kvm->devices, vm_node) {
list_del(&dev->vm_node);
dev->ops->destroy(dev);
}
}
static void kvm_destroy_vm(struct kvm *kvm)
{
int i;
struct mm_struct *mm = kvm->mm;
kvm_destroy_pm_notifier(kvm);
kvm_uevent_notify_change(KVM_EVENT_DESTROY_VM, kvm);
kvm_destroy_vm_debugfs(kvm);
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_for_destruction(kvm, i);
if (bus)
kvm_io_bus_destroy(bus);
kvm->buses[i] = NULL;
}
kvm_coalesced_mmio_free(kvm);
#ifdef CONFIG_KVM_GENERIC_MMU_NOTIFIER
mmu_notifier_unregister(&kvm->mmu_notifier, kvm->mm);
/*
* At this point, pending calls to invalidate_range_start()
* have completed but no more MMU notifiers will run, so
* mn_active_invalidate_count may remain unbalanced.
* No threads can be waiting in kvm_swap_active_memslots() as the
* last reference on KVM has been dropped, but freeing
* memslots would deadlock without this manual intervention.
*
* If the count isn't unbalanced, i.e. KVM did NOT unregister its MMU
* notifier between a start() and end(), then there shouldn't be any
* in-progress invalidations.
*/
WARN_ON(rcuwait_active(&kvm->mn_memslots_update_rcuwait));
if (kvm->mn_active_invalidate_count)
kvm->mn_active_invalidate_count = 0;
else
WARN_ON(kvm->mmu_invalidate_in_progress);
#else
kvm_flush_shadow_all(kvm);
#endif
kvm_arch_destroy_vm(kvm);
kvm_destroy_devices(kvm);
for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
kvm_free_memslots(kvm, &kvm->__memslots[i][0]);
kvm_free_memslots(kvm, &kvm->__memslots[i][1]);
}
cleanup_srcu_struct(&kvm->irq_srcu);
srcu_barrier(&kvm->srcu);
cleanup_srcu_struct(&kvm->srcu);
#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
xa_destroy(&kvm->mem_attr_array);
#endif
kvm_arch_free_vm(kvm);
preempt_notifier_dec();
kvm_disable_virtualization();
mmdrop(mm);
}
void kvm_get_kvm(struct kvm *kvm)
{
refcount_inc(&kvm->users_count);
}
EXPORT_SYMBOL_GPL(kvm_get_kvm);
/*
* Make sure the vm is not during destruction, which is a safe version of
* kvm_get_kvm(). Return true if kvm referenced successfully, false otherwise.
*/
bool kvm_get_kvm_safe(struct kvm *kvm)
{
return refcount_inc_not_zero(&kvm->users_count);
}
EXPORT_SYMBOL_GPL(kvm_get_kvm_safe);
void kvm_put_kvm(struct kvm *kvm)
{
if (refcount_dec_and_test(&kvm->users_count))
kvm_destroy_vm(kvm);
}
EXPORT_SYMBOL_GPL(kvm_put_kvm);
/*
* Used to put a reference that was taken on behalf of an object associated
* with a user-visible file descriptor, e.g. a vcpu or device, if installation
* of the new file descriptor fails and the reference cannot be transferred to
* its final owner. In such cases, the caller is still actively using @kvm and
* will fail miserably if the refcount unexpectedly hits zero.
*/
void kvm_put_kvm_no_destroy(struct kvm *kvm)
{
WARN_ON(refcount_dec_and_test(&kvm->users_count));
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(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;
}
int kvm_trylock_all_vcpus(struct kvm *kvm)
{
struct kvm_vcpu *vcpu;
unsigned long i, j;
lockdep_assert_held(&kvm->lock);
kvm_for_each_vcpu(i, vcpu, kvm)
if (!mutex_trylock_nest_lock(&vcpu->mutex, &kvm->lock))
goto out_unlock;
return 0;
out_unlock:
kvm_for_each_vcpu(j, vcpu, kvm) {
if (i == j)
break;
mutex_unlock(&vcpu->mutex);
}
return -EINTR;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_trylock_all_vcpus);
int kvm_lock_all_vcpus(struct kvm *kvm)
{
struct kvm_vcpu *vcpu;
unsigned long i, j;
int r;
lockdep_assert_held(&kvm->lock);
kvm_for_each_vcpu(i, vcpu, kvm) {
r = mutex_lock_killable_nest_lock(&vcpu->mutex, &kvm->lock);
if (r)
goto out_unlock;
}
return 0;
out_unlock:
kvm_for_each_vcpu(j, vcpu, kvm) {
if (i == j)
break;
mutex_unlock(&vcpu->mutex);
}
return r;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_lock_all_vcpus);
void kvm_unlock_all_vcpus(struct kvm *kvm)
{
struct kvm_vcpu *vcpu;
unsigned long i;
lockdep_assert_held(&kvm->lock);
kvm_for_each_vcpu(i, vcpu, kvm)
mutex_unlock(&vcpu->mutex);
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_unlock_all_vcpus);
/*
* Allocation size is twice as large as the actual dirty bitmap size.
* See kvm_vm_ioctl_get_dirty_log() why this is needed.
*/
static int kvm_alloc_dirty_bitmap(struct kvm_memory_slot *memslot)
{
unsigned long dirty_bytes = kvm_dirty_bitmap_bytes(memslot);
memslot->dirty_bitmap = __vcalloc(2, dirty_bytes, GFP_KERNEL_ACCOUNT);
if (!memslot->dirty_bitmap)
return -ENOMEM;
return 0;
}
static struct kvm_memslots *kvm_get_inactive_memslots(struct kvm *kvm, int as_id)
{
struct kvm_memslots *active = __kvm_memslots(kvm, as_id);
int node_idx_inactive = active->node_idx ^ 1;
return &kvm->__memslots[as_id][node_idx_inactive];
}
/*
* Helper to get the address space ID when one of memslot pointers may be NULL.
* This also serves as a sanity that at least one of the pointers is non-NULL,
* and that their address space IDs don't diverge.
*/
static int kvm_memslots_get_as_id(struct kvm_memory_slot *a,
struct kvm_memory_slot *b)
{
if (WARN_ON_ONCE(!a && !b))
return 0;
if (!a)
return b->as_id;
if (!b)
return a->as_id;
WARN_ON_ONCE(a->as_id != b->as_id);
return a->as_id;
}
static void kvm_insert_gfn_node(struct kvm_memslots *slots,
struct kvm_memory_slot *slot)
{
struct rb_root *gfn_tree = &slots->gfn_tree;
struct rb_node **node, *parent;
int idx = slots->node_idx;
parent = NULL;
for (node = &gfn_tree->rb_node; *node; ) {
struct kvm_memory_slot *tmp;
tmp = container_of(*node, struct kvm_memory_slot, gfn_node[idx]);
parent = *node;
if (slot->base_gfn < tmp->base_gfn)
node = &(*node)->rb_left;
else if (slot->base_gfn > tmp->base_gfn)
node = &(*node)->rb_right;
else
BUG();
}
rb_link_node(&slot->gfn_node[idx], parent, node);
rb_insert_color(&slot->gfn_node[idx], gfn_tree);
}
static void kvm_erase_gfn_node(struct kvm_memslots *slots,
struct kvm_memory_slot *slot)
{
rb_erase(&slot->gfn_node[slots->node_idx], &slots->gfn_tree);
}
static void kvm_replace_gfn_node(struct kvm_memslots *slots,
struct kvm_memory_slot *old,
struct kvm_memory_slot *new)
{
int idx = slots->node_idx;
WARN_ON_ONCE(old->base_gfn != new->base_gfn);
rb_replace_node(&old->gfn_node[idx], &new->gfn_node[idx],
&slots->gfn_tree);
}
/*
* Replace @old with @new in the inactive memslots.
*
* With NULL @old this simply adds @new.
* With NULL @new this simply removes @old.
*
* If @new is non-NULL its hva_node[slots_idx] range has to be set
* appropriately.
*/
static void kvm_replace_memslot(struct kvm *kvm,
struct kvm_memory_slot *old,
struct kvm_memory_slot *new)
{
int as_id = kvm_memslots_get_as_id(old, new);
struct kvm_memslots *slots = kvm_get_inactive_memslots(kvm, as_id);
int idx = slots->node_idx;
if (old) {
hash_del(&old->id_node[idx]);
interval_tree_remove(&old->hva_node[idx], &slots->hva_tree);
if ((long)old == atomic_long_read(&slots->last_used_slot))
atomic_long_set(&slots->last_used_slot, (long)new);
if (!new) {
kvm_erase_gfn_node(slots, old);
return;
}
}
/*
* Initialize @new's hva range. Do this even when replacing an @old
* slot, kvm_copy_memslot() deliberately does not touch node data.
*/
new->hva_node[idx].start = new->userspace_addr;
new->hva_node[idx].last = new->userspace_addr +
(new->npages << PAGE_SHIFT) - 1;
/*
* (Re)Add the new memslot. There is no O(1) interval_tree_replace(),
* hva_node needs to be swapped with remove+insert even though hva can't
* change when replacing an existing slot.
*/
hash_add(slots->id_hash, &new->id_node[idx], new->id);
interval_tree_insert(&new->hva_node[idx], &slots->hva_tree);
/*
* If the memslot gfn is unchanged, rb_replace_node() can be used to
* switch the node in the gfn tree instead of removing the old and
* inserting the new as two separate operations. Replacement is a
* single O(1) operation versus two O(log(n)) operations for
* remove+insert.
*/
if (old && old->base_gfn == new->base_gfn) {
kvm_replace_gfn_node(slots, old, new);
} else {
if (old)
kvm_erase_gfn_node(slots, old);
kvm_insert_gfn_node(slots, new);
}
}
/*
* Flags that do not access any of the extra space of struct
* kvm_userspace_memory_region2. KVM_SET_USER_MEMORY_REGION_V1_FLAGS
* only allows these.
*/
#define KVM_SET_USER_MEMORY_REGION_V1_FLAGS \
(KVM_MEM_LOG_DIRTY_PAGES | KVM_MEM_READONLY)
static int check_memory_region_flags(struct kvm *kvm,
const struct kvm_userspace_memory_region2 *mem)
{
u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES;
if (IS_ENABLED(CONFIG_KVM_GUEST_MEMFD))
valid_flags |= KVM_MEM_GUEST_MEMFD;
/* Dirty logging private memory is not currently supported. */
if (mem->flags & KVM_MEM_GUEST_MEMFD)
valid_flags &= ~KVM_MEM_LOG_DIRTY_PAGES;
/*
* GUEST_MEMFD is incompatible with read-only memslots, as writes to
* read-only memslots have emulated MMIO, not page fault, semantics,
* and KVM doesn't allow emulated MMIO for private memory.
*/
if (kvm_arch_has_readonly_mem(kvm) &&
!(mem->flags & KVM_MEM_GUEST_MEMFD))
valid_flags |= KVM_MEM_READONLY;
if (mem->flags & ~valid_flags)
return -EINVAL;
return 0;
}
static void kvm_swap_active_memslots(struct kvm *kvm, int as_id)
{
struct kvm_memslots *slots = kvm_get_inactive_memslots(kvm, as_id);
/* Grab the generation from the activate memslots. */
u64 gen = __kvm_memslots(kvm, as_id)->generation;
WARN_ON(gen & KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS);
slots->generation = gen | KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS;
/*
* Do not store the new memslots while there are invalidations in
* progress, otherwise the locking in invalidate_range_start and
* invalidate_range_end will be unbalanced.
*/
spin_lock(&kvm->mn_invalidate_lock);
prepare_to_rcuwait(&kvm->mn_memslots_update_rcuwait);
while (kvm->mn_active_invalidate_count) {
set_current_state(TASK_UNINTERRUPTIBLE);
spin_unlock(&kvm->mn_invalidate_lock);
schedule();
spin_lock(&kvm->mn_invalidate_lock);
}
finish_rcuwait(&kvm->mn_memslots_update_rcuwait);
rcu_assign_pointer(kvm->memslots[as_id], slots);
spin_unlock(&kvm->mn_invalidate_lock);
/*
* Acquired in kvm_set_memslot. Must be released before synchronize
* SRCU below in order to avoid deadlock with another thread
* acquiring the slots_arch_lock in an srcu critical section.
*/
mutex_unlock(&kvm->slots_arch_lock);
synchronize_srcu_expedited(&kvm->srcu);
/*
* Increment the new memslot generation a second time, dropping the
* update in-progress flag and incrementing the generation based on
* the number of address spaces. This provides a unique and easily
* identifiable generation number while the memslots are in flux.
*/
gen = slots->generation & ~KVM_MEMSLOT_GEN_UPDATE_IN_PROGRESS;
/*
* Generations must be unique even across address spaces. We do not need
* a global counter for that, instead the generation space is evenly split
* across address spaces. For example, with two address spaces, address
* space 0 will use generations 0, 2, 4, ... while address space 1 will
* use generations 1, 3, 5, ...
*/
gen += kvm_arch_nr_memslot_as_ids(kvm);
kvm_arch_memslots_updated(kvm, gen);
slots->generation = gen;
}
static int kvm_prepare_memory_region(struct kvm *kvm,
const struct kvm_memory_slot *old,
struct kvm_memory_slot *new,
enum kvm_mr_change change)
{
int r;
/*
* If dirty logging is disabled, nullify the bitmap; the old bitmap
* will be freed on "commit". If logging is enabled in both old and
* new, reuse the existing bitmap. If logging is enabled only in the
* new and KVM isn't using a ring buffer, allocate and initialize a
* new bitmap.
*/
if (change != KVM_MR_DELETE) {
if (!(new->flags & KVM_MEM_LOG_DIRTY_PAGES))
new->dirty_bitmap = NULL;
else if (old && old->dirty_bitmap)
new->dirty_bitmap = old->dirty_bitmap;
else if (kvm_use_dirty_bitmap(kvm)) {
r = kvm_alloc_dirty_bitmap(new);
if (r)
return r;
if (kvm_dirty_log_manual_protect_and_init_set(kvm))
bitmap_set(new->dirty_bitmap, 0, new->npages);
}
}
r = kvm_arch_prepare_memory_region(kvm, old, new, change);
/* Free the bitmap on failure if it was allocated above. */
if (r && new && new->dirty_bitmap && (!old || !old->dirty_bitmap))
kvm_destroy_dirty_bitmap(new);
return r;
}
static void kvm_commit_memory_region(struct kvm *kvm,
struct kvm_memory_slot *old,
const struct kvm_memory_slot *new,
enum kvm_mr_change change)
{
int old_flags = old ? old->flags : 0;
int new_flags = new ? new->flags : 0;
/*
* Update the total number of memslot pages before calling the arch
* hook so that architectures can consume the result directly.
*/
if (change == KVM_MR_DELETE)
kvm->nr_memslot_pages -= old->npages;
else if (change == KVM_MR_CREATE)
kvm->nr_memslot_pages += new->npages;
if ((old_flags ^ new_flags) & KVM_MEM_LOG_DIRTY_PAGES) {
int change = (new_flags & KVM_MEM_LOG_DIRTY_PAGES) ? 1 : -1;
atomic_set(&kvm->nr_memslots_dirty_logging,
atomic_read(&kvm->nr_memslots_dirty_logging) + change);
}
kvm_arch_commit_memory_region(kvm, old, new, change);
switch (change) {
case KVM_MR_CREATE:
/* Nothing more to do. */
break;
case KVM_MR_DELETE:
/* Free the old memslot and all its metadata. */
kvm_free_memslot(kvm, old);
break;
case KVM_MR_MOVE:
case KVM_MR_FLAGS_ONLY:
/*
* Free the dirty bitmap as needed; the below check encompasses
* both the flags and whether a ring buffer is being used)
*/
if (old->dirty_bitmap && !new->dirty_bitmap)
kvm_destroy_dirty_bitmap(old);
/*
* The final quirk. Free the detached, old slot, but only its
* memory, not any metadata. Metadata, including arch specific
* data, may be reused by @new.
*/
kfree(old);
break;
default:
BUG();
}
}
/*
* Activate @new, which must be installed in the inactive slots by the caller,
* by swapping the active slots and then propagating @new to @old once @old is
* unreachable and can be safely modified.
*
* With NULL @old this simply adds @new to @active (while swapping the sets).
* With NULL @new this simply removes @old from @active and frees it
* (while also swapping the sets).
*/
static void kvm_activate_memslot(struct kvm *kvm,
struct kvm_memory_slot *old,
struct kvm_memory_slot *new)
{
int as_id = kvm_memslots_get_as_id(old, new);
kvm_swap_active_memslots(kvm, as_id);
/* Propagate the new memslot to the now inactive memslots. */
kvm_replace_memslot(kvm, old, new);
}
static void kvm_copy_memslot(struct kvm_memory_slot *dest,
const struct kvm_memory_slot *src)
{
dest->base_gfn = src->base_gfn;
dest->npages = src->npages;
dest->dirty_bitmap = src->dirty_bitmap;
dest->arch = src->arch;
dest->userspace_addr = src->userspace_addr;
dest->flags = src->flags;
dest->id = src->id;
dest->as_id = src->as_id;
}
static void kvm_invalidate_memslot(struct kvm *kvm,
struct kvm_memory_slot *old,
struct kvm_memory_slot *invalid_slot)
{
/*
* Mark the current slot INVALID. As with all memslot modifications,
* this must be done on an unreachable slot to avoid modifying the
* current slot in the active tree.
*/
kvm_copy_memslot(invalid_slot, old);
invalid_slot->flags |= KVM_MEMSLOT_INVALID;
kvm_replace_memslot(kvm, old, invalid_slot);
/*
* Activate the slot that is now marked INVALID, but don't propagate
* the slot to the now inactive slots. The slot is either going to be
* deleted or recreated as a new slot.
*/
kvm_swap_active_memslots(kvm, old->as_id);
/*
* From this point no new shadow pages pointing to a deleted, or moved,
* memslot will be created. Validation of sp->gfn happens in:
* - gfn_to_hva (kvm_read_guest, gfn_to_pfn)
* - kvm_is_visible_gfn (mmu_check_root)
*/
kvm_arch_flush_shadow_memslot(kvm, old);
kvm_arch_guest_memory_reclaimed(kvm);
/* Was released by kvm_swap_active_memslots(), reacquire. */
mutex_lock(&kvm->slots_arch_lock);
/*
* Copy the arch-specific field of the newly-installed slot back to the
* old slot as the arch data could have changed between releasing
* slots_arch_lock in kvm_swap_active_memslots() and re-acquiring the lock
* above. Writers are required to retrieve memslots *after* acquiring
* slots_arch_lock, thus the active slot's data is guaranteed to be fresh.
*/
old->arch = invalid_slot->arch;
}
static void kvm_create_memslot(struct kvm *kvm,
struct kvm_memory_slot *new)
{
/* Add the new memslot to the inactive set and activate. */
kvm_replace_memslot(kvm, NULL, new);
kvm_activate_memslot(kvm, NULL, new);
}
static void kvm_delete_memslot(struct kvm *kvm,
struct kvm_memory_slot *old,
struct kvm_memory_slot *invalid_slot)
{
/*
* Remove the old memslot (in the inactive memslots) by passing NULL as
* the "new" slot, and for the invalid version in the active slots.
*/
kvm_replace_memslot(kvm, old, NULL);
kvm_activate_memslot(kvm, invalid_slot, NULL);
}
static void kvm_move_memslot(struct kvm *kvm,
struct kvm_memory_slot *old,
struct kvm_memory_slot *new,
struct kvm_memory_slot *invalid_slot)
{
/*
* Replace the old memslot in the inactive slots, and then swap slots
* and replace the current INVALID with the new as well.
*/
kvm_replace_memslot(kvm, old, new);
kvm_activate_memslot(kvm, invalid_slot, new);
}
static void kvm_update_flags_memslot(struct kvm *kvm,
struct kvm_memory_slot *old,
struct kvm_memory_slot *new)
{
/*
* Similar to the MOVE case, but the slot doesn't need to be zapped as
* an intermediate step. Instead, the old memslot is simply replaced
* with a new, updated copy in both memslot sets.
*/
kvm_replace_memslot(kvm, old, new);
kvm_activate_memslot(kvm, old, new);
}
static int kvm_set_memslot(struct kvm *kvm,
struct kvm_memory_slot *old,
struct kvm_memory_slot *new,
enum kvm_mr_change change)
{
struct kvm_memory_slot *invalid_slot;
int r;
/*
* Released in kvm_swap_active_memslots().
*
* Must be held from before the current memslots are copied until after
* the new memslots are installed with rcu_assign_pointer, then
* released before the synchronize srcu in kvm_swap_active_memslots().
*
* When modifying memslots outside of the slots_lock, must be held
* before reading the pointer to the current memslots until after all
* changes to those memslots are complete.
*
* These rules ensure that installing new memslots does not lose
* changes made to the previous memslots.
*/
mutex_lock(&kvm->slots_arch_lock);
/*
* Invalidate the old slot if it's being deleted or moved. This is
* done prior to actually deleting/moving the memslot to allow vCPUs to
* continue running by ensuring there are no mappings or shadow pages
* for the memslot when it is deleted/moved. Without pre-invalidation
* (and without a lock), a window would exist between effecting the
* delete/move and committing the changes in arch code where KVM or a
* guest could access a non-existent memslot.
*
* Modifications are done on a temporary, unreachable slot. The old
* slot needs to be preserved in case a later step fails and the
* invalidation needs to be reverted.
*/
if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) {
invalid_slot = kzalloc(sizeof(*invalid_slot), GFP_KERNEL_ACCOUNT);
if (!invalid_slot) {
mutex_unlock(&kvm->slots_arch_lock);
return -ENOMEM;
}
kvm_invalidate_memslot(kvm, old, invalid_slot);
}
r = kvm_prepare_memory_region(kvm, old, new, change);
if (r) {
/*
* For DELETE/MOVE, revert the above INVALID change. No
* modifications required since the original slot was preserved
* in the inactive slots. Changing the active memslots also
* release slots_arch_lock.
*/
if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) {
kvm_activate_memslot(kvm, invalid_slot, old);
kfree(invalid_slot);
} else {
mutex_unlock(&kvm->slots_arch_lock);
}
return r;
}
/*
* For DELETE and MOVE, the working slot is now active as the INVALID
* version of the old slot. MOVE is particularly special as it reuses
* the old slot and returns a copy of the old slot (in working_slot).
* For CREATE, there is no old slot. For DELETE and FLAGS_ONLY, the
* old slot is detached but otherwise preserved.
*/
if (change == KVM_MR_CREATE)
kvm_create_memslot(kvm, new);
else if (change == KVM_MR_DELETE)
kvm_delete_memslot(kvm, old, invalid_slot);
else if (change == KVM_MR_MOVE)
kvm_move_memslot(kvm, old, new, invalid_slot);
else if (change == KVM_MR_FLAGS_ONLY)
kvm_update_flags_memslot(kvm, old, new);
else
BUG();
/* Free the temporary INVALID slot used for DELETE and MOVE. */
if (change == KVM_MR_DELETE || change == KVM_MR_MOVE)
kfree(invalid_slot);
/*
* No need to refresh new->arch, changes after dropping slots_arch_lock
* will directly hit the final, active memslot. Architectures are
* responsible for knowing that new->arch may be stale.
*/
kvm_commit_memory_region(kvm, old, new, change);
return 0;
}
static bool kvm_check_memslot_overlap(struct kvm_memslots *slots, int id,
gfn_t start, gfn_t end)
{
struct kvm_memslot_iter iter;
kvm_for_each_memslot_in_gfn_range(&iter, slots, start, end) {
if (iter.slot->id != id)
return true;
}
return false;
}
static int kvm_set_memory_region(struct kvm *kvm,
const struct kvm_userspace_memory_region2 *mem)
{
struct kvm_memory_slot *old, *new;
struct kvm_memslots *slots;
enum kvm_mr_change change;
unsigned long npages;
gfn_t base_gfn;
int as_id, id;
int r;
lockdep_assert_held(&kvm->slots_lock);
r = check_memory_region_flags(kvm, mem);
if (r)
return r;
as_id = mem->slot >> 16;
id = (u16)mem->slot;
/* General sanity checks */
if ((mem->memory_size & (PAGE_SIZE - 1)) ||
(mem->memory_size != (unsigned long)mem->memory_size))
return -EINVAL;
if (mem->guest_phys_addr & (PAGE_SIZE - 1))
return -EINVAL;
/* We can read the guest memory with __xxx_user() later on. */
if ((mem->userspace_addr & (PAGE_SIZE - 1)) ||
(mem->userspace_addr != untagged_addr(mem->userspace_addr)) ||
!access_ok((void __user *)(unsigned long)mem->userspace_addr,
mem->memory_size))
return -EINVAL;
if (mem->flags & KVM_MEM_GUEST_MEMFD &&
(mem->guest_memfd_offset & (PAGE_SIZE - 1) ||
mem->guest_memfd_offset + mem->memory_size < mem->guest_memfd_offset))
return -EINVAL;
if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_MEM_SLOTS_NUM)
return -EINVAL;
if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr)
return -EINVAL;
/*
* The size of userspace-defined memory regions is restricted in order
* to play nice with dirty bitmap operations, which are indexed with an
* "unsigned int". KVM's internal memory regions don't support dirty
* logging, and so are exempt.
*/
if (id < KVM_USER_MEM_SLOTS &&
(mem->memory_size >> PAGE_SHIFT) > KVM_MEM_MAX_NR_PAGES)
return -EINVAL;
slots = __kvm_memslots(kvm, as_id);
/*
* Note, the old memslot (and the pointer itself!) may be invalidated
* and/or destroyed by kvm_set_memslot().
*/
old = id_to_memslot(slots, id);
if (!mem->memory_size) {
if (!old || !old->npages)
return -EINVAL;
if (WARN_ON_ONCE(kvm->nr_memslot_pages < old->npages))
return -EIO;
return kvm_set_memslot(kvm, old, NULL, KVM_MR_DELETE);
}
base_gfn = (mem->guest_phys_addr >> PAGE_SHIFT);
npages = (mem->memory_size >> PAGE_SHIFT);
if (!old || !old->npages) {
change = KVM_MR_CREATE;
/*
* To simplify KVM internals, the total number of pages across
* all memslots must fit in an unsigned long.
*/
if ((kvm->nr_memslot_pages + npages) < kvm->nr_memslot_pages)
return -EINVAL;
} else { /* Modify an existing slot. */
/* Private memslots are immutable, they can only be deleted. */
if (mem->flags & KVM_MEM_GUEST_MEMFD)
return -EINVAL;
if ((mem->userspace_addr != old->userspace_addr) ||
(npages != old->npages) ||
((mem->flags ^ old->flags) & KVM_MEM_READONLY))
return -EINVAL;
if (base_gfn != old->base_gfn)
change = KVM_MR_MOVE;
else if (mem->flags != old->flags)
change = KVM_MR_FLAGS_ONLY;
else /* Nothing to change. */
return 0;
}
if ((change == KVM_MR_CREATE || change == KVM_MR_MOVE) &&
kvm_check_memslot_overlap(slots, id, base_gfn, base_gfn + npages))
return -EEXIST;
/* Allocate a slot that will persist in the memslot. */
new = kzalloc(sizeof(*new), GFP_KERNEL_ACCOUNT);
if (!new)
return -ENOMEM;
new->as_id = as_id;
new->id = id;
new->base_gfn = base_gfn;
new->npages = npages;
new->flags = mem->flags;
new->userspace_addr = mem->userspace_addr;
if (mem->flags & KVM_MEM_GUEST_MEMFD) {
r = kvm_gmem_bind(kvm, new, mem->guest_memfd, mem->guest_memfd_offset);
if (r)
goto out;
}
r = kvm_set_memslot(kvm, old, new, change);
if (r)
goto out_unbind;
return 0;
out_unbind:
if (mem->flags & KVM_MEM_GUEST_MEMFD)
kvm_gmem_unbind(new);
out:
kfree(new);
return r;
}
int kvm_set_internal_memslot(struct kvm *kvm,
const struct kvm_userspace_memory_region2 *mem)
{
if (WARN_ON_ONCE(mem->slot < KVM_USER_MEM_SLOTS))
return -EINVAL;
if (WARN_ON_ONCE(mem->flags))
return -EINVAL;
return kvm_set_memory_region(kvm, mem);
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_set_internal_memslot);
static int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
struct kvm_userspace_memory_region2 *mem)
{
if ((u16)mem->slot >= KVM_USER_MEM_SLOTS)
return -EINVAL;
guard(mutex)(&kvm->slots_lock);
return kvm_set_memory_region(kvm, mem);
}
#ifndef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
/**
* kvm_get_dirty_log - get a snapshot of dirty pages
* @kvm: pointer to kvm instance
* @log: slot id and address to which we copy the log
* @is_dirty: set to '1' if any dirty pages were found
* @memslot: set to the associated memslot, always valid on success
*/
int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log,
int *is_dirty, struct kvm_memory_slot **memslot)
{
struct kvm_memslots *slots;
int i, as_id, id;
unsigned long n;
unsigned long any = 0;
/* Dirty ring tracking may be exclusive to dirty log tracking */
if (!kvm_use_dirty_bitmap(kvm))
return -ENXIO;
*memslot = NULL;
*is_dirty = 0;
as_id = log->slot >> 16;
id = (u16)log->slot;
if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_USER_MEM_SLOTS)
return -EINVAL;
slots = __kvm_memslots(kvm, as_id);
*memslot = id_to_memslot(slots, id);
if (!(*memslot) || !(*memslot)->dirty_bitmap)
return -ENOENT;
kvm_arch_sync_dirty_log(kvm, *memslot);
n = kvm_dirty_bitmap_bytes(*memslot);
for (i = 0; !any && i < n/sizeof(long); ++i)
any = (*memslot)->dirty_bitmap[i];
if (copy_to_user(log->dirty_bitmap, (*memslot)->dirty_bitmap, n))
return -EFAULT;
if (any)
*is_dirty = 1;
return 0;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_get_dirty_log);
#else /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
/**
* kvm_get_dirty_log_protect - get a snapshot of dirty pages
* and reenable dirty page tracking for the corresponding pages.
* @kvm: pointer to kvm instance
* @log: slot id and address to which we copy the log
*
* We need to keep it in mind that VCPU threads can write to the bitmap
* concurrently. So, to avoid losing track of dirty pages we keep the
* following order:
*
* 1. Take a snapshot of the bit and clear it if needed.
* 2. Write protect the corresponding page.
* 3. Copy the snapshot to the userspace.
* 4. Upon return caller flushes TLB's if needed.
*
* Between 2 and 4, the guest may write to the page using the remaining TLB
* entry. This is not a problem because the page is reported dirty using
* the snapshot taken before and step 4 ensures that writes done after
* exiting to userspace will be logged for the next call.
*
*/
static int kvm_get_dirty_log_protect(struct kvm *kvm, struct kvm_dirty_log *log)
{
struct kvm_memslots *slots;
struct kvm_memory_slot *memslot;
int i, as_id, id;
unsigned long n;
unsigned long *dirty_bitmap;
unsigned long *dirty_bitmap_buffer;
bool flush;
/* Dirty ring tracking may be exclusive to dirty log tracking */
if (!kvm_use_dirty_bitmap(kvm))
return -ENXIO;
as_id = log->slot >> 16;
id = (u16)log->slot;
if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_USER_MEM_SLOTS)
return -EINVAL;
slots = __kvm_memslots(kvm, as_id);
memslot = id_to_memslot(slots, id);
if (!memslot || !memslot->dirty_bitmap)
return -ENOENT;
dirty_bitmap = memslot->dirty_bitmap;
kvm_arch_sync_dirty_log(kvm, memslot);
n = kvm_dirty_bitmap_bytes(memslot);
flush = false;
if (kvm->manual_dirty_log_protect) {
/*
* Unlike kvm_get_dirty_log, we always return false in *flush,
* because no flush is needed until KVM_CLEAR_DIRTY_LOG. There
* is some code duplication between this function and
* kvm_get_dirty_log, but hopefully all architecture
* transition to kvm_get_dirty_log_protect and kvm_get_dirty_log
* can be eliminated.
*/
dirty_bitmap_buffer = dirty_bitmap;
} else {
dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot);
memset(dirty_bitmap_buffer, 0, n);
KVM_MMU_LOCK(kvm);
for (i = 0; i < n / sizeof(long); i++) {
unsigned long mask;
gfn_t offset;
if (!dirty_bitmap[i])
continue;
flush = true;
mask = xchg(&dirty_bitmap[i], 0);
dirty_bitmap_buffer[i] = mask;
offset = i * BITS_PER_LONG;
kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot,
offset, mask);
}
KVM_MMU_UNLOCK(kvm);
}
if (flush)
kvm_flush_remote_tlbs_memslot(kvm, memslot);
if (copy_to_user(log->dirty_bitmap, dirty_bitmap_buffer, n))
return -EFAULT;
return 0;
}
/**
* kvm_vm_ioctl_get_dirty_log - get and clear the log of dirty pages in a slot
* @kvm: kvm instance
* @log: slot id and address to which we copy the log
*
* Steps 1-4 below provide general overview of dirty page logging. See
* kvm_get_dirty_log_protect() function description for additional details.
*
* We call kvm_get_dirty_log_protect() to handle steps 1-3, upon return we
* always flush the TLB (step 4) even if previous step failed and the dirty
* bitmap may be corrupt. Regardless of previous outcome the KVM logging API
* does not preclude user space subsequent dirty log read. Flushing TLB ensures
* writes will be marked dirty for next log read.
*
* 1. Take a snapshot of the bit and clear it if needed.
* 2. Write protect the corresponding page.
* 3. Copy the snapshot to the userspace.
* 4. Flush TLB's if needed.
*/
static int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
struct kvm_dirty_log *log)
{
int r;
mutex_lock(&kvm->slots_lock);
r = kvm_get_dirty_log_protect(kvm, log);
mutex_unlock(&kvm->slots_lock);
return r;
}
/**
* kvm_clear_dirty_log_protect - clear dirty bits in the bitmap
* and reenable dirty page tracking for the corresponding pages.
* @kvm: pointer to kvm instance
* @log: slot id and address from which to fetch the bitmap of dirty pages
*/
static int kvm_clear_dirty_log_protect(struct kvm *kvm,
struct kvm_clear_dirty_log *log)
{
struct kvm_memslots *slots;
struct kvm_memory_slot *memslot;
int as_id, id;
gfn_t offset;
unsigned long i, n;
unsigned long *dirty_bitmap;
unsigned long *dirty_bitmap_buffer;
bool flush;
/* Dirty ring tracking may be exclusive to dirty log tracking */
if (!kvm_use_dirty_bitmap(kvm))
return -ENXIO;
as_id = log->slot >> 16;
id = (u16)log->slot;
if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_USER_MEM_SLOTS)
return -EINVAL;
if (log->first_page & 63)
return -EINVAL;
slots = __kvm_memslots(kvm, as_id);
memslot = id_to_memslot(slots, id);
if (!memslot || !memslot->dirty_bitmap)
return -ENOENT;
dirty_bitmap = memslot->dirty_bitmap;
n = ALIGN(log->num_pages, BITS_PER_LONG) / 8;
if (log->first_page > memslot->npages ||
log->num_pages > memslot->npages - log->first_page ||
(log->num_pages < memslot->npages - log->first_page && (log->num_pages & 63)))
return -EINVAL;
kvm_arch_sync_dirty_log(kvm, memslot);
flush = false;
dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot);
if (copy_from_user(dirty_bitmap_buffer, log->dirty_bitmap, n))
return -EFAULT;
KVM_MMU_LOCK(kvm);
for (offset = log->first_page, i = offset / BITS_PER_LONG,
n = DIV_ROUND_UP(log->num_pages, BITS_PER_LONG); n--;
i++, offset += BITS_PER_LONG) {
unsigned long mask = *dirty_bitmap_buffer++;
atomic_long_t *p = (atomic_long_t *) &dirty_bitmap[i];
if (!mask)
continue;
mask &= atomic_long_fetch_andnot(mask, p);
/*
* mask contains the bits that really have been cleared. This
* never includes any bits beyond the length of the memslot (if
* the length is not aligned to 64 pages), therefore it is not
* a problem if userspace sets them in log->dirty_bitmap.
*/
if (mask) {
flush = true;
kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot,
offset, mask);
}
}
KVM_MMU_UNLOCK(kvm);
if (flush)
kvm_flush_remote_tlbs_memslot(kvm, memslot);
return 0;
}
static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
struct kvm_clear_dirty_log *log)
{
int r;
mutex_lock(&kvm->slots_lock);
r = kvm_clear_dirty_log_protect(kvm, log);
mutex_unlock(&kvm->slots_lock);
return r;
}
#endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
static u64 kvm_supported_mem_attributes(struct kvm *kvm)
{
if (!kvm || kvm_arch_has_private_mem(kvm))
return KVM_MEMORY_ATTRIBUTE_PRIVATE;
return 0;
}
/*
* Returns true if _all_ gfns in the range [@start, @end) have attributes
* such that the bits in @mask match @attrs.
*/
bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
unsigned long mask, unsigned long attrs)
{
XA_STATE(xas, &kvm->mem_attr_array, start);
unsigned long index;
void *entry;
mask &= kvm_supported_mem_attributes(kvm);
if (attrs & ~mask)
return false;
if (end == start + 1)
return (kvm_get_memory_attributes(kvm, start) & mask) == attrs;
guard(rcu)();
if (!attrs)
return !xas_find(&xas, end - 1);
for (index = start; index < end; index++) {
do {
entry = xas_next(&xas);
} while (xas_retry(&xas, entry));
if (xas.xa_index != index ||
(xa_to_value(entry) & mask) != attrs)
return false;
}
return true;
}
static __always_inline void kvm_handle_gfn_range(struct kvm *kvm,
struct kvm_mmu_notifier_range *range)
{
struct kvm_gfn_range gfn_range;
struct kvm_memory_slot *slot;
struct kvm_memslots *slots;
struct kvm_memslot_iter iter;
bool found_memslot = false;
bool ret = false;
int i;
gfn_range.arg = range->arg;
gfn_range.may_block = range->may_block;
/*
* If/when KVM supports more attributes beyond private .vs shared, this
* _could_ set KVM_FILTER_{SHARED,PRIVATE} appropriately if the entire target
* range already has the desired private vs. shared state (it's unclear
* if that is a net win). For now, KVM reaches this point if and only
* if the private flag is being toggled, i.e. all mappings are in play.
*/
for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
slots = __kvm_memslots(kvm, i);
kvm_for_each_memslot_in_gfn_range(&iter, slots, range->start, range->end) {
slot = iter.slot;
gfn_range.slot = slot;
gfn_range.start = max(range->start, slot->base_gfn);
gfn_range.end = min(range->end, slot->base_gfn + slot->npages);
if (gfn_range.start >= gfn_range.end)
continue;
if (!found_memslot) {
found_memslot = true;
KVM_MMU_LOCK(kvm);
if (!IS_KVM_NULL_FN(range->on_lock))
range->on_lock(kvm);
}
ret |= range->handler(kvm, &gfn_range);
}
}
if (range->flush_on_ret && ret)
kvm_flush_remote_tlbs(kvm);
if (found_memslot)
KVM_MMU_UNLOCK(kvm);
}
static bool kvm_pre_set_memory_attributes(struct kvm *kvm,
struct kvm_gfn_range *range)
{
/*
* Unconditionally add the range to the invalidation set, regardless of
* whether or not the arch callback actually needs to zap SPTEs. E.g.
* if KVM supports RWX attributes in the future and the attributes are
* going from R=>RW, zapping isn't strictly necessary. Unconditionally
* adding the range allows KVM to require that MMU invalidations add at
* least one range between begin() and end(), e.g. allows KVM to detect
* bugs where the add() is missed. Relaxing the rule *might* be safe,
* but it's not obvious that allowing new mappings while the attributes
* are in flux is desirable or worth the complexity.
*/
kvm_mmu_invalidate_range_add(kvm, range->start, range->end);
return kvm_arch_pre_set_memory_attributes(kvm, range);
}
/* Set @attributes for the gfn range [@start, @end). */
static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
unsigned long attributes)
{
struct kvm_mmu_notifier_range pre_set_range = {
.start = start,
.end = end,
.arg.attributes = attributes,
.handler = kvm_pre_set_memory_attributes,
.on_lock = kvm_mmu_invalidate_begin,
.flush_on_ret = true,
.may_block = true,
};
struct kvm_mmu_notifier_range post_set_range = {
.start = start,
.end = end,
.arg.attributes = attributes,
.handler = kvm_arch_post_set_memory_attributes,
.on_lock = kvm_mmu_invalidate_end,
.may_block = true,
};
unsigned long i;
void *entry;
int r = 0;
entry = attributes ? xa_mk_value(attributes) : NULL;
trace_kvm_vm_set_mem_attributes(start, end, attributes);
mutex_lock(&kvm->slots_lock);
/* Nothing to do if the entire range has the desired attributes. */
if (kvm_range_has_memory_attributes(kvm, start, end, ~0, attributes))
goto out_unlock;
/*
* Reserve memory ahead of time to avoid having to deal with failures
* partway through setting the new attributes.
*/
for (i = start; i < end; i++) {
r = xa_reserve(&kvm->mem_attr_array, i, GFP_KERNEL_ACCOUNT);
if (r)
goto out_unlock;
cond_resched();
}
kvm_handle_gfn_range(kvm, &pre_set_range);
for (i = start; i < end; i++) {
r = xa_err(xa_store(&kvm->mem_attr_array, i, entry,
GFP_KERNEL_ACCOUNT));
KVM_BUG_ON(r, kvm);
cond_resched();
}
kvm_handle_gfn_range(kvm, &post_set_range);
out_unlock:
mutex_unlock(&kvm->slots_lock);
return r;
}
static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
struct kvm_memory_attributes *attrs)
{
gfn_t start, end;
/* flags is currently not used. */
if (attrs->flags)
return -EINVAL;
if (attrs->attributes & ~kvm_supported_mem_attributes(kvm))
return -EINVAL;
if (attrs->size == 0 || attrs->address + attrs->size < attrs->address)
return -EINVAL;
if (!PAGE_ALIGNED(attrs->address) || !PAGE_ALIGNED(attrs->size))
return -EINVAL;
start = attrs->address >> PAGE_SHIFT;
end = (attrs->address + attrs->size) >> PAGE_SHIFT;
/*
* xarray tracks data using "unsigned long", and as a result so does
* KVM. For simplicity, supports generic attributes only on 64-bit
* architectures.
*/
BUILD_BUG_ON(sizeof(attrs->attributes) != sizeof(unsigned long));
return kvm_vm_set_mem_attributes(kvm, start, end, attrs->attributes);
}
#endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */
struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
{
return __gfn_to_memslot(kvm_memslots(kvm), gfn);
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(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;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(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 bool kvm_is_ad_tracked_page(struct page *page)
{
/*
* Per page-flags.h, pages tagged PG_reserved "should in general not be
* touched (e.g. set dirty) except by its owner".
*/
return !PageReserved(page);
}
static void kvm_set_page_dirty(struct page *page)
{
if (kvm_is_ad_tracked_page(page))
SetPageDirty(page);
}
static void kvm_set_page_accessed(struct page *page)
{
if (kvm_is_ad_tracked_page(page))
mark_page_accessed(page);
}
void kvm_release_page_clean(struct page *page)
{
if (!page)
return;
kvm_set_page_accessed(page);
put_page(page);
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_release_page_clean);
void kvm_release_page_dirty(struct page *page)
{
if (!page)
return;
kvm_set_page_dirty(page);
kvm_release_page_clean(page);
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_release_page_dirty);
static kvm_pfn_t kvm_resolve_pfn(struct kvm_follow_pfn *kfp, struct page *page,
struct follow_pfnmap_args *map, bool writable)
{
kvm_pfn_t pfn;
WARN_ON_ONCE(!!page == !!map);
if (kfp->map_writable)
*kfp->map_writable = writable;
if (map)
pfn = map->pfn;
else
pfn = page_to_pfn(page);
*kfp->refcounted_page = page;
return pfn;
}
/*
* The fast path to get the writable pfn which will be stored in @pfn,
* true indicates success, otherwise false is returned.
*/
static bool hva_to_pfn_fast(struct kvm_follow_pfn *kfp, kvm_pfn_t *pfn)
{
struct page *page;
bool r;
/*
* Try the fast-only path when the caller wants to pin/get the page for
* writing. If the caller only wants to read the page, KVM must go
* down the full, slow path in order to avoid racing an operation that
* breaks Copy-on-Write (CoW), e.g. so that KVM doesn't end up pointing
* at the old, read-only page while mm/ points at a new, writable page.
*/
if (!((kfp->flags & FOLL_WRITE) || kfp->map_writable))
return false;
if (kfp->pin)
r = pin_user_pages_fast(kfp->hva, 1, FOLL_WRITE, &page) == 1;
else
r = get_user_page_fast_only(kfp->hva, FOLL_WRITE, &page);
if (r) {
*pfn = kvm_resolve_pfn(kfp, page, NULL, 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(struct kvm_follow_pfn *kfp, kvm_pfn_t *pfn)
{
/*
* When a VCPU accesses a page that is not mapped into the secondary
* MMU, we lookup the page using GUP to map it, so the guest VCPU can
* make progress. We always want to honor NUMA hinting faults in that
* case, because GUP usage corresponds to memory accesses from the VCPU.
* Otherwise, we'd not trigger NUMA hinting faults once a page is
* mapped into the secondary MMU and gets accessed by a VCPU.
*
* Note that get_user_page_fast_only() and FOLL_WRITE for now
* implicitly honor NUMA hinting faults and don't need this flag.
*/
unsigned int flags = FOLL_HWPOISON | FOLL_HONOR_NUMA_FAULT | kfp->flags;
struct page *page, *wpage;
int npages;
if (kfp->pin)
npages = pin_user_pages_unlocked(kfp->hva, 1, &page, flags);
else
npages = get_user_pages_unlocked(kfp->hva, 1, &page, flags);
if (npages != 1)
return npages;
/*
* Pinning is mutually exclusive with opportunistically mapping a read
* fault as writable, as KVM should never pin pages when mapping memory
* into the guest (pinning is only for direct accesses from KVM).
*/
if (WARN_ON_ONCE(kfp->map_writable && kfp->pin))
goto out;
/* map read fault as writable if possible */
if (!(flags & FOLL_WRITE) && kfp->map_writable &&
get_user_page_fast_only(kfp->hva, FOLL_WRITE, &wpage)) {
put_page(page);
page = wpage;
flags |= FOLL_WRITE;
}
out:
*pfn = kvm_resolve_pfn(kfp, page, NULL, flags & FOLL_WRITE);
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,
struct kvm_follow_pfn *kfp, kvm_pfn_t *p_pfn)
{
struct follow_pfnmap_args args = { .vma = vma, .address = kfp->hva };
bool write_fault = kfp->flags & FOLL_WRITE;
int r;
/*
* Remapped memory cannot be pinned in any meaningful sense. Bail if
* the caller wants to pin the page, i.e. access the page outside of
* MMU notifier protection, and unsafe umappings are disallowed.
*/
if (kfp->pin && !allow_unsafe_mappings)
return -EINVAL;
r = follow_pfnmap_start(&args);
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, kfp->hva,
(write_fault ? FAULT_FLAG_WRITE : 0),
&unlocked);
if (unlocked)
return -EAGAIN;
if (r)
return r;
r = follow_pfnmap_start(&args);
if (r)
return r;
}
if (write_fault && !args.writable) {
*p_pfn = KVM_PFN_ERR_RO_FAULT;
goto out;
}
*p_pfn = kvm_resolve_pfn(kfp, NULL, &args, args.writable);
out:
follow_pfnmap_end(&args);
return r;
}
kvm_pfn_t hva_to_pfn(struct kvm_follow_pfn *kfp)
{
struct vm_area_struct *vma;
kvm_pfn_t pfn;
int npages, r;
might_sleep();
if (WARN_ON_ONCE(!kfp->refcounted_page))
return KVM_PFN_ERR_FAULT;
if (hva_to_pfn_fast(kfp, &pfn))
return pfn;
npages = hva_to_pfn_slow(kfp, &pfn);
if (npages == 1)
return pfn;
if (npages == -EINTR || npages == -EAGAIN)
return KVM_PFN_ERR_SIGPENDING;
if (npages == -EHWPOISON)
return KVM_PFN_ERR_HWPOISON;
mmap_read_lock(current->mm);
retry:
vma = vma_lookup(current->mm, kfp->hva);
if (vma == NULL)
pfn = KVM_PFN_ERR_FAULT;
else if (vma->vm_flags & (VM_IO | VM_PFNMAP)) {
r = hva_to_pfn_remapped(vma, kfp, &pfn);
if (r == -EAGAIN)
goto retry;
if (r < 0)
pfn = KVM_PFN_ERR_FAULT;
} else {
if ((kfp->flags & FOLL_NOWAIT) &&
vma_is_valid(vma, kfp->flags & FOLL_WRITE))
pfn = KVM_PFN_ERR_NEEDS_IO;
else
pfn = KVM_PFN_ERR_FAULT;
}
mmap_read_unlock(current->mm);
return pfn;
}
static kvm_pfn_t kvm_follow_pfn(struct kvm_follow_pfn *kfp)
{
kfp->hva = __gfn_to_hva_many(kfp->slot, kfp->gfn, NULL,
kfp->flags & FOLL_WRITE);
if (kfp->hva == KVM_HVA_ERR_RO_BAD)
return KVM_PFN_ERR_RO_FAULT;
if (kvm_is_error_hva(kfp->hva))
return KVM_PFN_NOSLOT;
if (memslot_is_readonly(kfp->slot) && kfp->map_writable) {
*kfp->map_writable = false;
kfp->map_writable = NULL;
}
return hva_to_pfn(kfp);
}
kvm_pfn_t __kvm_faultin_pfn(const struct kvm_memory_slot *slot, gfn_t gfn,
unsigned int foll, bool *writable,
struct page **refcounted_page)
{
struct kvm_follow_pfn kfp = {
.slot = slot,
.gfn = gfn,
.flags = foll,
.map_writable = writable,
.refcounted_page = refcounted_page,
};
if (WARN_ON_ONCE(!writable || !refcounted_page))
return KVM_PFN_ERR_FAULT;
*writable = false;
*refcounted_page = NULL;
return kvm_follow_pfn(&kfp);
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(__kvm_faultin_pfn);
int kvm_prefetch_pages(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_FOR_KVM_INTERNAL(kvm_prefetch_pages);
/*
* Don't use this API unless you are absolutely, positively certain that KVM
* needs to get a struct page, e.g. to pin the page for firmware DMA.
*
* FIXME: Users of this API likely need to FOLL_PIN the page, not just elevate
* its refcount.
*/
struct page *__gfn_to_page(struct kvm *kvm, gfn_t gfn, bool write)
{
struct page *refcounted_page = NULL;
struct kvm_follow_pfn kfp = {
.slot = gfn_to_memslot(kvm, gfn),
.gfn = gfn,
.flags = write ? FOLL_WRITE : 0,
.refcounted_page = &refcounted_page,
};
(void)kvm_follow_pfn(&kfp);
return refcounted_page;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(__gfn_to_page);
int __kvm_vcpu_map(struct kvm_vcpu *vcpu, gfn_t gfn, struct kvm_host_map *map,
bool writable)
{
struct kvm_follow_pfn kfp = {
.slot = gfn_to_memslot(vcpu->kvm, gfn),
.gfn = gfn,
.flags = writable ? FOLL_WRITE : 0,
.refcounted_page = &map->pinned_page,
.pin = true,
};
map->pinned_page = NULL;
map->page = NULL;
map->hva = NULL;
map->gfn = gfn;
map->writable = writable;
map->pfn = kvm_follow_pfn(&kfp);
if (is_error_noslot_pfn(map->pfn))
return -EINVAL;
if (pfn_valid(map->pfn)) {
map->page = pfn_to_page(map->pfn);
map->hva = kmap(map->page);
#ifdef CONFIG_HAS_IOMEM
} else {
map->hva = memremap(pfn_to_hpa(map->pfn), PAGE_SIZE, MEMREMAP_WB);
#endif
}
return map->hva ? 0 : -EFAULT;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(__kvm_vcpu_map);
void kvm_vcpu_unmap(struct kvm_vcpu *vcpu, struct kvm_host_map *map)
{
if (!map->hva)
return;
if (map->page)
kunmap(map->page);
#ifdef CONFIG_HAS_IOMEM
else
memunmap(map->hva);
#endif
if (map->writable)
kvm_vcpu_mark_page_dirty(vcpu, map->gfn);
if (map->pinned_page) {
if (map->writable)
kvm_set_page_dirty(map->pinned_page);
kvm_set_page_accessed(map->pinned_page);
unpin_user_page(map->pinned_page);
}
map->hva = NULL;
map->page = NULL;
map->pinned_page = NULL;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_unmap);
static int next_segment(unsigned long len, int offset)
{
if (len > PAGE_SIZE - offset)
return PAGE_SIZE - offset;
else
return len;
}
/* Copy @len bytes from guest memory at '(@gfn * PAGE_SIZE) + @offset' to @data */
static int __kvm_read_guest_page(struct kvm_memory_slot *slot, gfn_t gfn,
void *data, int offset, int len)
{
int r;
unsigned long addr;
if (WARN_ON_ONCE(offset + len > PAGE_SIZE))
return -EFAULT;
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_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(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;
if (WARN_ON_ONCE(offset + len > PAGE_SIZE))
return -EFAULT;
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_FOR_KVM_INTERNAL(kvm_vcpu_read_guest_atomic);
/* Copy @len bytes from @data into guest memory at '(@gfn * PAGE_SIZE) + @offset' */
static int __kvm_write_guest_page(struct kvm *kvm,
struct kvm_memory_slot *memslot, gfn_t gfn,
const void *data, int offset, int len)
{
int r;
unsigned long addr;
if (WARN_ON_ONCE(offset + len > PAGE_SIZE))
return -EFAULT;
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_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(kvm_gfn_to_hva_cache_init);
int kvm_write_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
void *data, unsigned int offset,
unsigned long len)
{
struct kvm_memslots *slots = kvm_memslots(kvm);
int r;
gpa_t gpa = ghc->gpa + offset;
if (WARN_ON_ONCE(len + offset > ghc->len))
return -EINVAL;
if (slots->generation != ghc->generation) {
if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len))
return -EFAULT;
}
if (kvm_is_error_hva(ghc->hva))
return -EFAULT;
if (unlikely(!ghc->memslot))
return kvm_write_guest(kvm, gpa, data, len);
r = __copy_to_user((void __user *)ghc->hva + offset, data, len);
if (r)
return -EFAULT;
mark_page_dirty_in_slot(kvm, ghc->memslot, gpa >> PAGE_SHIFT);
return 0;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(kvm_write_guest_cached);
int kvm_read_guest_offset_cached(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
void *data, unsigned int offset,
unsigned long len)
{
struct kvm_memslots *slots = kvm_memslots(kvm);
int r;
gpa_t gpa = ghc->gpa + offset;
if (WARN_ON_ONCE(len + offset > ghc->len))
return -EINVAL;
if (slots->generation != ghc->generation) {
if (__kvm_gfn_to_hva_cache_init(slots, ghc, ghc->gpa, ghc->len))
return -EFAULT;
}
if (kvm_is_error_hva(ghc->hva))
return -EFAULT;
if (unlikely(!ghc->memslot))
return kvm_read_guest(kvm, gpa, data, len);
r = __copy_from_user(data, (void __user *)ghc->hva + offset, len);
if (r)
return -EFAULT;
return 0;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(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, seg);
if (ret < 0)
return ret;
offset = 0;
len -= seg;
++gfn;
}
return 0;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_clear_guest);
void mark_page_dirty_in_slot(struct kvm *kvm,
const struct kvm_memory_slot *memslot,
gfn_t gfn)
{
struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
#ifdef CONFIG_HAVE_KVM_DIRTY_RING
if (WARN_ON_ONCE(vcpu && vcpu->kvm != kvm))
return;
WARN_ON_ONCE(!vcpu && !kvm_arch_allow_write_without_running_vcpu(kvm));
#endif
if (memslot && kvm_slot_dirty_track_enabled(memslot)) {
unsigned long rel_gfn = gfn - memslot->base_gfn;
u32 slot = (memslot->as_id << 16) | memslot->id;
if (kvm->dirty_ring_size && vcpu)
kvm_dirty_ring_push(vcpu, slot, rel_gfn);
else if (memslot->dirty_bitmap)
set_bit_le(rel_gfn, memslot->dirty_bitmap);
}
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(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_FOR_KVM_INTERNAL(kvm_vcpu_mark_page_dirty);
void kvm_sigset_activate(struct kvm_vcpu *vcpu)
{
if (!vcpu->sigset_active)
return;
/*
* This does a lockless modification of ->real_blocked, which is fine
* because, only current can change ->real_blocked and all readers of
* ->real_blocked don't care as long ->real_blocked is always a subset
* of ->blocked.
*/
sigprocmask(SIG_SETMASK, &vcpu->sigset, &current->real_blocked);
}
void kvm_sigset_deactivate(struct kvm_vcpu *vcpu)
{
if (!vcpu->sigset_active)
return;
sigprocmask(SIG_SETMASK, &current->real_blocked, NULL);
sigemptyset(&current->real_blocked);
}
static void grow_halt_poll_ns(struct kvm_vcpu *vcpu)
{
unsigned int old, val, grow, grow_start;
old = val = vcpu->halt_poll_ns;
grow_start = READ_ONCE(halt_poll_ns_grow_start);
grow = READ_ONCE(halt_poll_ns_grow);
if (!grow)
goto out;
val *= grow;
if (val < grow_start)
val = grow_start;
vcpu->halt_poll_ns = val;
out:
trace_kvm_halt_poll_ns_grow(vcpu->vcpu_id, val, old);
}
static void shrink_halt_poll_ns(struct kvm_vcpu *vcpu)
{
unsigned int old, val, shrink, grow_start;
old = val = vcpu->halt_poll_ns;
shrink = READ_ONCE(halt_poll_ns_shrink);
grow_start = READ_ONCE(halt_poll_ns_grow_start);
if (shrink == 0)
val = 0;
else
val /= shrink;
if (val < grow_start)
val = 0;
vcpu->halt_poll_ns = val;
trace_kvm_halt_poll_ns_shrink(vcpu->vcpu_id, val, old);
}
static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu)
{
int ret = -EINTR;
int idx = srcu_read_lock(&vcpu->kvm->srcu);
if (kvm_arch_vcpu_runnable(vcpu))
goto out;
if (kvm_cpu_has_pending_timer(vcpu))
goto out;
if (signal_pending(current))
goto out;
if (kvm_check_request(KVM_REQ_UNBLOCK, vcpu))
goto out;
ret = 0;
out:
srcu_read_unlock(&vcpu->kvm->srcu, idx);
return ret;
}
/*
* Block the vCPU until the vCPU is runnable, an event arrives, or a signal is
* pending. This is mostly used when halting a vCPU, but may also be used
* directly for other vCPU non-runnable states, e.g. x86's Wait-For-SIPI.
*/
bool kvm_vcpu_block(struct kvm_vcpu *vcpu)
{
struct rcuwait *wait = kvm_arch_vcpu_get_wait(vcpu);
bool waited = false;
vcpu->stat.generic.blocking = 1;
preempt_disable();
kvm_arch_vcpu_blocking(vcpu);
prepare_to_rcuwait(wait);
preempt_enable();
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (kvm_vcpu_check_block(vcpu) < 0)
break;
waited = true;
schedule();
}
preempt_disable();
finish_rcuwait(wait);
kvm_arch_vcpu_unblocking(vcpu);
preempt_enable();
vcpu->stat.generic.blocking = 0;
return waited;
}
static inline void update_halt_poll_stats(struct kvm_vcpu *vcpu, ktime_t start,
ktime_t end, bool success)
{
struct kvm_vcpu_stat_generic *stats = &vcpu->stat.generic;
u64 poll_ns = ktime_to_ns(ktime_sub(end, start));
++vcpu->stat.generic.halt_attempted_poll;
if (success) {
++vcpu->stat.generic.halt_successful_poll;
if (!vcpu_valid_wakeup(vcpu))
++vcpu->stat.generic.halt_poll_invalid;
stats->halt_poll_success_ns += poll_ns;
KVM_STATS_LOG_HIST_UPDATE(stats->halt_poll_success_hist, poll_ns);
} else {
stats->halt_poll_fail_ns += poll_ns;
KVM_STATS_LOG_HIST_UPDATE(stats->halt_poll_fail_hist, poll_ns);
}
}
static unsigned int kvm_vcpu_max_halt_poll_ns(struct kvm_vcpu *vcpu)
{
struct kvm *kvm = vcpu->kvm;
if (kvm->override_halt_poll_ns) {
/*
* Ensure kvm->max_halt_poll_ns is not read before
* kvm->override_halt_poll_ns.
*
* Pairs with the smp_wmb() when enabling KVM_CAP_HALT_POLL.
*/
smp_rmb();
return READ_ONCE(kvm->max_halt_poll_ns);
}
return READ_ONCE(halt_poll_ns);
}
/*
* Emulate a vCPU halt condition, e.g. HLT on x86, WFI on arm, etc... If halt
* polling is enabled, busy wait for a short time before blocking to avoid the
* expensive block+unblock sequence if a wake event arrives soon after the vCPU
* is halted.
*/
void kvm_vcpu_halt(struct kvm_vcpu *vcpu)
{
unsigned int max_halt_poll_ns = kvm_vcpu_max_halt_poll_ns(vcpu);
bool halt_poll_allowed = !kvm_arch_no_poll(vcpu);
ktime_t start, cur, poll_end;
bool waited = false;
bool do_halt_poll;
u64 halt_ns;
if (vcpu->halt_poll_ns > max_halt_poll_ns)
vcpu->halt_poll_ns = max_halt_poll_ns;
do_halt_poll = halt_poll_allowed && vcpu->halt_poll_ns;
start = cur = poll_end = ktime_get();
if (do_halt_poll) {
ktime_t stop = ktime_add_ns(start, vcpu->halt_poll_ns);
do {
if (kvm_vcpu_check_block(vcpu) < 0)
goto out;
cpu_relax();
poll_end = cur = ktime_get();
} while (kvm_vcpu_can_poll(cur, stop));
}
waited = kvm_vcpu_block(vcpu);
cur = ktime_get();
if (waited) {
vcpu->stat.generic.halt_wait_ns +=
ktime_to_ns(cur) - ktime_to_ns(poll_end);
KVM_STATS_LOG_HIST_UPDATE(vcpu->stat.generic.halt_wait_hist,
ktime_to_ns(cur) - ktime_to_ns(poll_end));
}
out:
/* The total time the vCPU was "halted", including polling time. */
halt_ns = ktime_to_ns(cur) - ktime_to_ns(start);
/*
* Note, halt-polling is considered successful so long as the vCPU was
* never actually scheduled out, i.e. even if the wake event arrived
* after of the halt-polling loop itself, but before the full wait.
*/
if (do_halt_poll)
update_halt_poll_stats(vcpu, start, poll_end, !waited);
if (halt_poll_allowed) {
/* Recompute the max halt poll time in case it changed. */
max_halt_poll_ns = kvm_vcpu_max_halt_poll_ns(vcpu);
if (!vcpu_valid_wakeup(vcpu)) {
shrink_halt_poll_ns(vcpu);
} else if (max_halt_poll_ns) {
if (halt_ns <= vcpu->halt_poll_ns)
;
/* we had a long block, shrink polling */
else if (vcpu->halt_poll_ns &&
halt_ns > max_halt_poll_ns)
shrink_halt_poll_ns(vcpu);
/* we had a short halt and our poll time is too small */
else if (vcpu->halt_poll_ns < max_halt_poll_ns &&
halt_ns < max_halt_poll_ns)
grow_halt_poll_ns(vcpu);
} else {
vcpu->halt_poll_ns = 0;
}
}
trace_kvm_vcpu_wakeup(halt_ns, waited, vcpu_valid_wakeup(vcpu));
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_halt);
bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu)
{
if (__kvm_vcpu_wake_up(vcpu)) {
WRITE_ONCE(vcpu->ready, true);
++vcpu->stat.generic.halt_wakeup;
return true;
}
return false;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_wake_up);
#ifndef CONFIG_S390
/*
* Kick a sleeping VCPU, or a guest VCPU in guest mode, into host kernel mode.
*/
void __kvm_vcpu_kick(struct kvm_vcpu *vcpu, bool wait)
{
int me, cpu;
if (kvm_vcpu_wake_up(vcpu))
return;
me = get_cpu();
/*
* The only state change done outside the vcpu mutex is IN_GUEST_MODE
* to EXITING_GUEST_MODE. Therefore the moderately expensive "should
* kick" check does not need atomic operations if kvm_vcpu_kick is used
* within the vCPU thread itself.
*/
if (vcpu == __this_cpu_read(kvm_running_vcpu)) {
if (vcpu->mode == IN_GUEST_MODE)
WRITE_ONCE(vcpu->mode, EXITING_GUEST_MODE);
goto out;
}
/*
* Note, the vCPU could get migrated to a different pCPU at any point
* after kvm_arch_vcpu_should_kick(), which could result in sending an
* IPI to the previous pCPU. But, that's ok because the purpose of the
* IPI is to force the vCPU to leave IN_GUEST_MODE, and migrating the
* vCPU also requires it to leave IN_GUEST_MODE.
*/
if (kvm_arch_vcpu_should_kick(vcpu)) {
cpu = READ_ONCE(vcpu->cpu);
if (cpu != me && (unsigned int)cpu < nr_cpu_ids && cpu_online(cpu)) {
/*
* Use a reschedule IPI to kick the vCPU if the caller
* doesn't need to wait for a response, as KVM allows
* kicking vCPUs while IRQs are disabled, but using the
* SMP function call framework with IRQs disabled can
* deadlock due to taking cross-CPU locks.
*/
if (wait)
smp_call_function_single(cpu, ack_kick, NULL, wait);
else
smp_send_reschedule(cpu);
}
}
out:
put_cpu();
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(__kvm_vcpu_kick);
#endif /* !CONFIG_S390 */
int kvm_vcpu_yield_to(struct kvm_vcpu *target)
{
struct task_struct *task = NULL;
int ret;
if (!read_trylock(&target->pid_lock))
return 0;
if (target->pid)
task = get_pid_task(target->pid, PIDTYPE_PID);
read_unlock(&target->pid_lock);
if (!task)
return 0;
ret = yield_to(task, 1);
put_task_struct(task);
return ret;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_yield_to);
/*
* Helper that checks whether a VCPU is eligible for directed yield.
* Most eligible candidate to yield is decided by following heuristics:
*
* (a) VCPU which has not done pl-exit or cpu relax intercepted recently
* (preempted lock holder), indicated by @in_spin_loop.
* Set at the beginning and cleared at the end of interception/PLE handler.
*
* (b) VCPU which has done pl-exit/ cpu relax intercepted but did not get
* chance last time (mostly it has become eligible now since we have probably
* yielded to lockholder in last iteration. This is done by toggling
* @dy_eligible each time a VCPU checked for eligibility.)
*
* Yielding to a recently pl-exited/cpu relax intercepted VCPU before yielding
* to preempted lock-holder could result in wrong VCPU selection and CPU
* burning. Giving priority for a potential lock-holder increases lock
* progress.
*
* Since algorithm is based on heuristics, accessing another VCPU data without
* locking does not harm. It may result in trying to yield to same VCPU, fail
* and continue with next VCPU and so on.
*/
static bool kvm_vcpu_eligible_for_directed_yield(struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT
bool eligible;
eligible = !vcpu->spin_loop.in_spin_loop ||
vcpu->spin_loop.dy_eligible;
if (vcpu->spin_loop.in_spin_loop)
kvm_vcpu_set_dy_eligible(vcpu, !vcpu->spin_loop.dy_eligible);
return eligible;
#else
return true;
#endif
}
/*
* Unlike kvm_arch_vcpu_runnable, this function is called outside
* a vcpu_load/vcpu_put pair. However, for most architectures
* kvm_arch_vcpu_runnable does not require vcpu_load.
*/
bool __weak kvm_arch_dy_runnable(struct kvm_vcpu *vcpu)
{
return kvm_arch_vcpu_runnable(vcpu);
}
static bool vcpu_dy_runnable(struct kvm_vcpu *vcpu)
{
if (kvm_arch_dy_runnable(vcpu))
return true;
#ifdef CONFIG_KVM_ASYNC_PF
if (!list_empty_careful(&vcpu->async_pf.done))
return true;
#endif
return false;
}
/*
* By default, simply query the target vCPU's current mode when checking if a
* vCPU was preempted in kernel mode. All architectures except x86 (or more
* specifical, except VMX) allow querying whether or not a vCPU is in kernel
* mode even if the vCPU is NOT loaded, i.e. using kvm_arch_vcpu_in_kernel()
* directly for cross-vCPU checks is functionally correct and accurate.
*/
bool __weak kvm_arch_vcpu_preempted_in_kernel(struct kvm_vcpu *vcpu)
{
return kvm_arch_vcpu_in_kernel(vcpu);
}
bool __weak kvm_arch_dy_has_pending_interrupt(struct kvm_vcpu *vcpu)
{
return false;
}
void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode)
{
int nr_vcpus, start, i, idx, yielded;
struct kvm *kvm = me->kvm;
struct kvm_vcpu *vcpu;
int try = 3;
nr_vcpus = atomic_read(&kvm->online_vcpus);
if (nr_vcpus < 2)
return;
/* Pairs with the smp_wmb() in kvm_vm_ioctl_create_vcpu(). */
smp_rmb();
kvm_vcpu_set_in_spin_loop(me, true);
/*
* The current vCPU ("me") is spinning in kernel mode, i.e. is likely
* waiting for a resource to become available. Attempt to yield to a
* vCPU that is runnable, but not currently running, e.g. because the
* vCPU was preempted by a higher priority task. With luck, the vCPU
* that was preempted is holding a lock or some other resource that the
* current vCPU is waiting to acquire, and yielding to the other vCPU
* will allow it to make forward progress and release the lock (or kick
* the spinning vCPU, etc).
*
* Since KVM has no insight into what exactly the guest is doing,
* approximate a round-robin selection by iterating over all vCPUs,
* starting at the last boosted vCPU. I.e. if N=kvm->last_boosted_vcpu,
* iterate over vCPU[N+1]..vCPU[N-1], wrapping as needed.
*
* Note, this is inherently racy, e.g. if multiple vCPUs are spinning,
* they may all try to yield to the same vCPU(s). But as above, this
* is all best effort due to KVM's lack of visibility into the guest.
*/
start = READ_ONCE(kvm->last_boosted_vcpu) + 1;
for (i = 0; i < nr_vcpus; i++) {
idx = (start + i) % nr_vcpus;
if (idx == me->vcpu_idx)
continue;
vcpu = xa_load(&kvm->vcpu_array, idx);
if (!READ_ONCE(vcpu->ready))
continue;
if (kvm_vcpu_is_blocking(vcpu) && !vcpu_dy_runnable(vcpu))
continue;
/*
* Treat the target vCPU as being in-kernel if it has a pending
* interrupt, as the vCPU trying to yield may be spinning
* waiting on IPI delivery, i.e. the target vCPU is in-kernel
* for the purposes of directed yield.
*/
if (READ_ONCE(vcpu->preempted) && yield_to_kernel_mode &&
!kvm_arch_dy_has_pending_interrupt(vcpu) &&
!kvm_arch_vcpu_preempted_in_kernel(vcpu))
continue;
if (!kvm_vcpu_eligible_for_directed_yield(vcpu))
continue;
yielded = kvm_vcpu_yield_to(vcpu);
if (yielded > 0) {
WRITE_ONCE(kvm->last_boosted_vcpu, i);
break;
} else if (yielded < 0 && !--try) {
break;
}
}
kvm_vcpu_set_in_spin_loop(me, false);
/* Ensure vcpu is not eligible during next spinloop */
kvm_vcpu_set_dy_eligible(me, false);
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_vcpu_on_spin);
static bool kvm_page_in_dirty_ring(struct kvm *kvm, unsigned long pgoff)
{
#ifdef CONFIG_HAVE_KVM_DIRTY_RING
return (pgoff >= KVM_DIRTY_LOG_PAGE_OFFSET) &&
(pgoff < KVM_DIRTY_LOG_PAGE_OFFSET +
kvm->dirty_ring_size / PAGE_SIZE);
#else
return false;
#endif
}
static vm_fault_t kvm_vcpu_fault(struct vm_fault *vmf)
{
struct kvm_vcpu *vcpu = vmf->vma->vm_file->private_data;
struct page *page;
if (vmf->pgoff == 0)
page = virt_to_page(vcpu->run);
#ifdef CONFIG_X86
else if (vmf->pgoff == KVM_PIO_PAGE_OFFSET)
page = virt_to_page(vcpu->arch.pio_data);
#endif
#ifdef CONFIG_KVM_MMIO
else if (vmf->pgoff == KVM_COALESCED_MMIO_PAGE_OFFSET)
page = virt_to_page(vcpu->kvm->coalesced_mmio_ring);
#endif
else if (kvm_page_in_dirty_ring(vcpu->kvm, vmf->pgoff))
page = kvm_dirty_ring_get_page(
&vcpu->dirty_ring,
vmf->pgoff - KVM_DIRTY_LOG_PAGE_OFFSET);
else
return kvm_arch_vcpu_fault(vcpu, vmf);
get_page(page);
vmf->page = page;
return 0;
}
static const struct vm_operations_struct kvm_vcpu_vm_ops = {
.fault = kvm_vcpu_fault,
};
static int kvm_vcpu_mmap(struct file *file, struct vm_area_struct *vma)
{
struct kvm_vcpu *vcpu = file->private_data;
unsigned long pages = vma_pages(vma);
if ((kvm_page_in_dirty_ring(vcpu->kvm, vma->vm_pgoff) ||
kvm_page_in_dirty_ring(vcpu->kvm, vma->vm_pgoff + pages - 1)) &&
((vma->vm_flags & VM_EXEC) || !(vma->vm_flags & VM_SHARED)))
return -EINVAL;
vma->vm_ops = &kvm_vcpu_vm_ops;
return 0;
}
static int kvm_vcpu_release(struct inode *inode, struct file *filp)
{
struct kvm_vcpu *vcpu = filp->private_data;
kvm_put_kvm(vcpu->kvm);
return 0;
}
static struct file_operations kvm_vcpu_fops = {
.release = kvm_vcpu_release,
.unlocked_ioctl = kvm_vcpu_ioctl,
.mmap = kvm_vcpu_mmap,
.llseek = noop_llseek,
KVM_COMPAT(kvm_vcpu_compat_ioctl),
};
/*
* Allocates an inode for the vcpu.
*/
static int create_vcpu_fd(struct kvm_vcpu *vcpu)
{
char name[8 + 1 + ITOA_MAX_LEN + 1];
snprintf(name, sizeof(name), "kvm-vcpu:%d", vcpu->vcpu_id);
return anon_inode_getfd(name, &kvm_vcpu_fops, vcpu, O_RDWR | O_CLOEXEC);
}
#ifdef __KVM_HAVE_ARCH_VCPU_DEBUGFS
static int vcpu_get_pid(void *data, u64 *val)
{
struct kvm_vcpu *vcpu = data;
read_lock(&vcpu->pid_lock);
*val = pid_nr(vcpu->pid);
read_unlock(&vcpu->pid_lock);
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(vcpu_get_pid_fops, vcpu_get_pid, NULL, "%llu\n");
static void kvm_create_vcpu_debugfs(struct kvm_vcpu *vcpu)
{
struct dentry *debugfs_dentry;
char dir_name[ITOA_MAX_LEN * 2];
if (!debugfs_initialized())
return;
snprintf(dir_name, sizeof(dir_name), "vcpu%d", vcpu->vcpu_id);
debugfs_dentry = debugfs_create_dir(dir_name,
vcpu->kvm->debugfs_dentry);
debugfs_create_file("pid", 0444, debugfs_dentry, vcpu,
&vcpu_get_pid_fops);
kvm_arch_create_vcpu_debugfs(vcpu, debugfs_dentry);
}
#endif
/*
* Creates some virtual cpus. Good luck creating more than one.
*/
static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, unsigned long id)
{
int r;
struct kvm_vcpu *vcpu;
struct page *page;
/*
* KVM tracks vCPU IDs as 'int', be kind to userspace and reject
* too-large values instead of silently truncating.
*
* Ensure KVM_MAX_VCPU_IDS isn't pushed above INT_MAX without first
* changing the storage type (at the very least, IDs should be tracked
* as unsigned ints).
*/
BUILD_BUG_ON(KVM_MAX_VCPU_IDS > INT_MAX);
if (id >= KVM_MAX_VCPU_IDS)
return -EINVAL;
mutex_lock(&kvm->lock);
if (kvm->created_vcpus >= kvm->max_vcpus) {
mutex_unlock(&kvm->lock);
return -EINVAL;
}
r = kvm_arch_vcpu_precreate(kvm, id);
if (r) {
mutex_unlock(&kvm->lock);
return r;
}
kvm->created_vcpus++;
mutex_unlock(&kvm->lock);
vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL_ACCOUNT);
if (!vcpu) {
r = -ENOMEM;
goto vcpu_decrement;
}
BUILD_BUG_ON(sizeof(struct kvm_run) > PAGE_SIZE);
page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
if (!page) {
r = -ENOMEM;
goto vcpu_free;
}
vcpu->run = page_address(page);
kvm_vcpu_init(vcpu, kvm, id);
r = kvm_arch_vcpu_create(vcpu);
if (r)
goto vcpu_free_run_page;
if (kvm->dirty_ring_size) {
r = kvm_dirty_ring_alloc(kvm, &vcpu->dirty_ring,
id, kvm->dirty_ring_size);
if (r)
goto arch_vcpu_destroy;
}
mutex_lock(&kvm->lock);
if (kvm_get_vcpu_by_id(kvm, id)) {
r = -EEXIST;
goto unlock_vcpu_destroy;
}
vcpu->vcpu_idx = atomic_read(&kvm->online_vcpus);
r = xa_insert(&kvm->vcpu_array, vcpu->vcpu_idx, vcpu, GFP_KERNEL_ACCOUNT);
WARN_ON_ONCE(r == -EBUSY);
if (r)
goto unlock_vcpu_destroy;
/*
* Now it's all set up, let userspace reach it. Grab the vCPU's mutex
* so that userspace can't invoke vCPU ioctl()s until the vCPU is fully
* visible (per online_vcpus), e.g. so that KVM doesn't get tricked
* into a NULL-pointer dereference because KVM thinks the _current_
* vCPU doesn't exist. As a bonus, taking vcpu->mutex ensures lockdep
* knows it's taken *inside* kvm->lock.
*/
mutex_lock(&vcpu->mutex);
kvm_get_kvm(kvm);
r = create_vcpu_fd(vcpu);
if (r < 0)
goto kvm_put_xa_erase;
/*
* Pairs with smp_rmb() in kvm_get_vcpu. Store the vcpu
* pointer before kvm->online_vcpu's incremented value.
*/
smp_wmb();
atomic_inc(&kvm->online_vcpus);
mutex_unlock(&vcpu->mutex);
mutex_unlock(&kvm->lock);
kvm_arch_vcpu_postcreate(vcpu);
kvm_create_vcpu_debugfs(vcpu);
return r;
kvm_put_xa_erase:
mutex_unlock(&vcpu->mutex);
kvm_put_kvm_no_destroy(kvm);
xa_erase(&kvm->vcpu_array, vcpu->vcpu_idx);
unlock_vcpu_destroy:
mutex_unlock(&kvm->lock);
kvm_dirty_ring_free(&vcpu->dirty_ring);
arch_vcpu_destroy:
kvm_arch_vcpu_destroy(vcpu);
vcpu_free_run_page:
free_page((unsigned long)vcpu->run);
vcpu_free:
kmem_cache_free(kvm_vcpu_cache, vcpu);
vcpu_decrement:
mutex_lock(&kvm->lock);
kvm->created_vcpus--;
mutex_unlock(&kvm->lock);
return r;
}
static int kvm_vcpu_ioctl_set_sigmask(struct kvm_vcpu *vcpu, sigset_t *sigset)
{
if (sigset) {
sigdelsetmask(sigset, sigmask(SIGKILL)|sigmask(SIGSTOP));
vcpu->sigset_active = 1;
vcpu->sigset = *sigset;
} else
vcpu->sigset_active = 0;
return 0;
}
static ssize_t kvm_vcpu_stats_read(struct file *file, char __user *user_buffer,
size_t size, loff_t *offset)
{
struct kvm_vcpu *vcpu = file->private_data;
return kvm_stats_read(vcpu->stats_id, &kvm_vcpu_stats_header,
&kvm_vcpu_stats_desc[0], &vcpu->stat,
sizeof(vcpu->stat), user_buffer, size, offset);
}
static int kvm_vcpu_stats_release(struct inode *inode, struct file *file)
{
struct kvm_vcpu *vcpu = file->private_data;
kvm_put_kvm(vcpu->kvm);
return 0;
}
static const struct file_operations kvm_vcpu_stats_fops = {
.owner = THIS_MODULE,
.read = kvm_vcpu_stats_read,
.release = kvm_vcpu_stats_release,
.llseek = noop_llseek,
};
static int kvm_vcpu_ioctl_get_stats_fd(struct kvm_vcpu *vcpu)
{
int fd;
struct file *file;
char name[15 + ITOA_MAX_LEN + 1];
snprintf(name, sizeof(name), "kvm-vcpu-stats:%d", vcpu->vcpu_id);
fd = get_unused_fd_flags(O_CLOEXEC);
if (fd < 0)
return fd;
file = anon_inode_getfile_fmode(name, &kvm_vcpu_stats_fops, vcpu,
O_RDONLY, FMODE_PREAD);
if (IS_ERR(file)) {
put_unused_fd(fd);
return PTR_ERR(file);
}
kvm_get_kvm(vcpu->kvm);
fd_install(fd, file);
return fd;
}
#ifdef CONFIG_KVM_GENERIC_PRE_FAULT_MEMORY
static int kvm_vcpu_pre_fault_memory(struct kvm_vcpu *vcpu,
struct kvm_pre_fault_memory *range)
{
int idx;
long r;
u64 full_size;
if (range->flags)
return -EINVAL;
if (!PAGE_ALIGNED(range->gpa) ||
!PAGE_ALIGNED(range->size) ||
range->gpa + range->size <= range->gpa)
return -EINVAL;
vcpu_load(vcpu);
idx = srcu_read_lock(&vcpu->kvm->srcu);
full_size = range->size;
do {
if (signal_pending(current)) {
r = -EINTR;
break;
}
r = kvm_arch_vcpu_pre_fault_memory(vcpu, range);
if (WARN_ON_ONCE(r == 0 || r == -EIO))
break;
if (r < 0)
break;
range->size -= r;
range->gpa += r;
cond_resched();
} while (range->size);
srcu_read_unlock(&vcpu->kvm->srcu, idx);
vcpu_put(vcpu);
/* Return success if at least one page was mapped successfully. */
return full_size == range->size ? r : 0;
}
#endif
static int kvm_wait_for_vcpu_online(struct kvm_vcpu *vcpu)
{
struct kvm *kvm = vcpu->kvm;
/*
* In practice, this happy path will always be taken, as a well-behaved
* VMM will never invoke a vCPU ioctl() before KVM_CREATE_VCPU returns.
*/
if (likely(vcpu->vcpu_idx < atomic_read(&kvm->online_vcpus)))
return 0;
/*
* Acquire and release the vCPU's mutex to wait for vCPU creation to
* complete (kvm_vm_ioctl_create_vcpu() holds the mutex until the vCPU
* is fully online).
*/
if (mutex_lock_killable(&vcpu->mutex))
return -EINTR;
mutex_unlock(&vcpu->mutex);
if (WARN_ON_ONCE(!kvm_get_vcpu(kvm, vcpu->vcpu_idx)))
return -EIO;
return 0;
}
static long kvm_vcpu_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
struct kvm_vcpu *vcpu = filp->private_data;
void __user *argp = (void __user *)arg;
int r;
struct kvm_fpu *fpu = NULL;
struct kvm_sregs *kvm_sregs = NULL;
if (vcpu->kvm->mm != current->mm || vcpu->kvm->vm_dead)
return -EIO;
if (unlikely(_IOC_TYPE(ioctl) != KVMIO))
return -EINVAL;
/*
* Wait for the vCPU to be online before handling the ioctl(), as KVM
* assumes the vCPU is reachable via vcpu_array, i.e. may dereference
* a NULL pointer if userspace invokes an ioctl() before KVM is ready.
*/
r = kvm_wait_for_vcpu_online(vcpu);
if (r)
return r;
/*
* Some architectures have vcpu ioctls that are asynchronous to vcpu
* execution; mutex_lock() would break them.
*/
r = kvm_arch_vcpu_async_ioctl(filp, ioctl, arg);
if (r != -ENOIOCTLCMD)
return r;
if (mutex_lock_killable(&vcpu->mutex))
return -EINTR;
switch (ioctl) {
case KVM_RUN: {
struct pid *oldpid;
r = -EINVAL;
if (arg)
goto out;
/*
* Note, vcpu->pid is primarily protected by vcpu->mutex. The
* dedicated r/w lock allows other tasks, e.g. other vCPUs, to
* read vcpu->pid while this vCPU is in KVM_RUN, e.g. to yield
* directly to this vCPU
*/
oldpid = vcpu->pid;
if (unlikely(oldpid != task_pid(current))) {
/* The thread running this VCPU changed. */
struct pid *newpid;
r = kvm_arch_vcpu_run_pid_change(vcpu);
if (r)
break;
newpid = get_task_pid(current, PIDTYPE_PID);
write_lock(&vcpu->pid_lock);
vcpu->pid = newpid;
write_unlock(&vcpu->pid_lock);
put_pid(oldpid);
}
vcpu->wants_to_run = !READ_ONCE(vcpu->run->immediate_exit__unsafe);
r = kvm_arch_vcpu_ioctl_run(vcpu);
vcpu->wants_to_run = false;
trace_kvm_userspace_exit(vcpu->run->exit_reason, r);
break;
}
case KVM_GET_REGS: {
struct kvm_regs *kvm_regs;
r = -ENOMEM;
kvm_regs = kzalloc(sizeof(struct kvm_regs), GFP_KERNEL);
if (!kvm_regs)
goto out;
r = kvm_arch_vcpu_ioctl_get_regs(vcpu, kvm_regs);
if (r)
goto out_free1;
r = -EFAULT;
if (copy_to_user(argp, kvm_regs, sizeof(struct kvm_regs)))
goto out_free1;
r = 0;
out_free1:
kfree(kvm_regs);
break;
}
case KVM_SET_REGS: {
struct kvm_regs *kvm_regs;
kvm_regs = memdup_user(argp, sizeof(*kvm_regs));
if (IS_ERR(kvm_regs)) {
r = PTR_ERR(kvm_regs);
goto out;
}
r = kvm_arch_vcpu_ioctl_set_regs(vcpu, kvm_regs);
kfree(kvm_regs);
break;
}
case KVM_GET_SREGS: {
kvm_sregs = kzalloc(sizeof(struct kvm_sregs), GFP_KERNEL);
r = -ENOMEM;
if (!kvm_sregs)
goto out;
r = kvm_arch_vcpu_ioctl_get_sregs(vcpu, kvm_sregs);
if (r)
goto out;
r = -EFAULT;
if (copy_to_user(argp, kvm_sregs, sizeof(struct kvm_sregs)))
goto out;
r = 0;
break;
}
case KVM_SET_SREGS: {
kvm_sregs = memdup_user(argp, sizeof(*kvm_sregs));
if (IS_ERR(kvm_sregs)) {
r = PTR_ERR(kvm_sregs);
kvm_sregs = NULL;
goto out;
}
r = kvm_arch_vcpu_ioctl_set_sregs(vcpu, kvm_sregs);
break;
}
case KVM_GET_MP_STATE: {
struct kvm_mp_state mp_state;
r = kvm_arch_vcpu_ioctl_get_mpstate(vcpu, &mp_state);
if (r)
goto out;
r = -EFAULT;
if (copy_to_user(argp, &mp_state, sizeof(mp_state)))
goto out;
r = 0;
break;
}
case KVM_SET_MP_STATE: {
struct kvm_mp_state mp_state;
r = -EFAULT;
if (copy_from_user(&mp_state, argp, sizeof(mp_state)))
goto out;
r = kvm_arch_vcpu_ioctl_set_mpstate(vcpu, &mp_state);
break;
}
case KVM_TRANSLATE: {
struct kvm_translation tr;
r = -EFAULT;
if (copy_from_user(&tr, argp, sizeof(tr)))
goto out;
r = kvm_arch_vcpu_ioctl_translate(vcpu, &tr);
if (r)
goto out;
r = -EFAULT;
if (copy_to_user(argp, &tr, sizeof(tr)))
goto out;
r = 0;
break;
}
case KVM_SET_GUEST_DEBUG: {
struct kvm_guest_debug dbg;
r = -EFAULT;
if (copy_from_user(&dbg, argp, sizeof(dbg)))
goto out;
r = kvm_arch_vcpu_ioctl_set_guest_debug(vcpu, &dbg);
break;
}
case KVM_SET_SIGNAL_MASK: {
struct kvm_signal_mask __user *sigmask_arg = argp;
struct kvm_signal_mask kvm_sigmask;
sigset_t sigset, *p;
p = NULL;
if (argp) {
r = -EFAULT;
if (copy_from_user(&kvm_sigmask, argp,
sizeof(kvm_sigmask)))
goto out;
r = -EINVAL;
if (kvm_sigmask.len != sizeof(sigset))
goto out;
r = -EFAULT;
if (copy_from_user(&sigset, sigmask_arg->sigset,
sizeof(sigset)))
goto out;
p = &sigset;
}
r = kvm_vcpu_ioctl_set_sigmask(vcpu, p);
break;
}
case KVM_GET_FPU: {
fpu = kzalloc(sizeof(struct kvm_fpu), GFP_KERNEL);
r = -ENOMEM;
if (!fpu)
goto out;
r = kvm_arch_vcpu_ioctl_get_fpu(vcpu, fpu);
if (r)
goto out;
r = -EFAULT;
if (copy_to_user(argp, fpu, sizeof(struct kvm_fpu)))
goto out;
r = 0;
break;
}
case KVM_SET_FPU: {
fpu = memdup_user(argp, sizeof(*fpu));
if (IS_ERR(fpu)) {
r = PTR_ERR(fpu);
fpu = NULL;
goto out;
}
r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, fpu);
break;
}
case KVM_GET_STATS_FD: {
r = kvm_vcpu_ioctl_get_stats_fd(vcpu);
break;
}
#ifdef CONFIG_KVM_GENERIC_PRE_FAULT_MEMORY
case KVM_PRE_FAULT_MEMORY: {
struct kvm_pre_fault_memory range;
r = -EFAULT;
if (copy_from_user(&range, argp, sizeof(range)))
break;
r = kvm_vcpu_pre_fault_memory(vcpu, &range);
/* Pass back leftover range. */
if (copy_to_user(argp, &range, sizeof(range)))
r = -EFAULT;
break;
}
#endif
default:
r = kvm_arch_vcpu_ioctl(filp, ioctl, arg);
}
out:
mutex_unlock(&vcpu->mutex);
kfree(fpu);
kfree(kvm_sregs);
return r;
}
#ifdef CONFIG_KVM_COMPAT
static long kvm_vcpu_compat_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
struct kvm_vcpu *vcpu = filp->private_data;
void __user *argp = compat_ptr(arg);
int r;
if (vcpu->kvm->mm != current->mm || vcpu->kvm->vm_dead)
return -EIO;
switch (ioctl) {
case KVM_SET_SIGNAL_MASK: {
struct kvm_signal_mask __user *sigmask_arg = argp;
struct kvm_signal_mask kvm_sigmask;
sigset_t sigset;
if (argp) {
r = -EFAULT;
if (copy_from_user(&kvm_sigmask, argp,
sizeof(kvm_sigmask)))
goto out;
r = -EINVAL;
if (kvm_sigmask.len != sizeof(compat_sigset_t))
goto out;
r = -EFAULT;
if (get_compat_sigset(&sigset,
(compat_sigset_t __user *)sigmask_arg->sigset))
goto out;
r = kvm_vcpu_ioctl_set_sigmask(vcpu, &sigset);
} else
r = kvm_vcpu_ioctl_set_sigmask(vcpu, NULL);
break;
}
default:
r = kvm_vcpu_ioctl(filp, ioctl, arg);
}
out:
return r;
}
#endif
static int kvm_device_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct kvm_device *dev = filp->private_data;
if (dev->ops->mmap)
return dev->ops->mmap(dev, vma);
return -ENODEV;
}
static int kvm_device_ioctl_attr(struct kvm_device *dev,
int (*accessor)(struct kvm_device *dev,
struct kvm_device_attr *attr),
unsigned long arg)
{
struct kvm_device_attr attr;
if (!accessor)
return -EPERM;
if (copy_from_user(&attr, (void __user *)arg, sizeof(attr)))
return -EFAULT;
return accessor(dev, &attr);
}
static long kvm_device_ioctl(struct file *filp, unsigned int ioctl,
unsigned long arg)
{
struct kvm_device *dev = filp->private_data;
if (dev->kvm->mm != current->mm || dev->kvm->vm_dead)
return -EIO;
switch (ioctl) {
case KVM_SET_DEVICE_ATTR:
return kvm_device_ioctl_attr(dev, dev->ops->set_attr, arg);
case KVM_GET_DEVICE_ATTR:
return kvm_device_ioctl_attr(dev, dev->ops->get_attr, arg);
case KVM_HAS_DEVICE_ATTR:
return kvm_device_ioctl_attr(dev, dev->ops->has_attr, arg);
default:
if (dev->ops->ioctl)
return dev->ops->ioctl(dev, ioctl, arg);
return -ENOTTY;
}
}
static int kvm_device_release(struct inode *inode, struct file *filp)
{
struct kvm_device *dev = filp->private_data;
struct kvm *kvm = dev->kvm;
if (dev->ops->release) {
mutex_lock(&kvm->lock);
list_del_rcu(&dev->vm_node);
synchronize_rcu();
dev->ops->release(dev);
mutex_unlock(&kvm->lock);
}
kvm_put_kvm(kvm);
return 0;
}
static struct file_operations kvm_device_fops = {
.unlocked_ioctl = kvm_device_ioctl,
.release = kvm_device_release,
KVM_COMPAT(kvm_device_ioctl),
.mmap = kvm_device_mmap,
};
struct kvm_device *kvm_device_from_filp(struct file *filp)
{
if (filp->f_op != &kvm_device_fops)
return NULL;
return filp->private_data;
}
static const struct kvm_device_ops *kvm_device_ops_table[KVM_DEV_TYPE_MAX] = {
#ifdef CONFIG_KVM_MPIC
[KVM_DEV_TYPE_FSL_MPIC_20] = &kvm_mpic_ops,
[KVM_DEV_TYPE_FSL_MPIC_42] = &kvm_mpic_ops,
#endif
};
int kvm_register_device_ops(const struct kvm_device_ops *ops, u32 type)
{
if (type >= ARRAY_SIZE(kvm_device_ops_table))
return -ENOSPC;
if (kvm_device_ops_table[type] != NULL)
return -EEXIST;
kvm_device_ops_table[type] = ops;
return 0;
}
void kvm_unregister_device_ops(u32 type)
{
if (kvm_device_ops_table[type] != NULL)
kvm_device_ops_table[type] = NULL;
}
static int kvm_ioctl_create_device(struct kvm *kvm,
struct kvm_create_device *cd)
{
const struct kvm_device_ops *ops;
struct kvm_device *dev;
bool test = cd->flags & KVM_CREATE_DEVICE_TEST;
int type;
int ret;
if (cd->type >= ARRAY_SIZE(kvm_device_ops_table))
return -ENODEV;
type = array_index_nospec(cd->type, ARRAY_SIZE(kvm_device_ops_table));
ops = kvm_device_ops_table[type];
if (ops == NULL)
return -ENODEV;
if (test)
return 0;
dev = kzalloc(sizeof(*dev), GFP_KERNEL_ACCOUNT);
if (!dev)
return -ENOMEM;
dev->ops = ops;
dev->kvm = kvm;
mutex_lock(&kvm->lock);
ret = ops->create(dev, type);
if (ret < 0) {
mutex_unlock(&kvm->lock);
kfree(dev);
return ret;
}
list_add_rcu(&dev->vm_node, &kvm->devices);
mutex_unlock(&kvm->lock);
if (ops->init)
ops->init(dev);
kvm_get_kvm(kvm);
ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC);
if (ret < 0) {
kvm_put_kvm_no_destroy(kvm);
mutex_lock(&kvm->lock);
list_del_rcu(&dev->vm_node);
synchronize_rcu();
if (ops->release)
ops->release(dev);
mutex_unlock(&kvm->lock);
if (ops->destroy)
ops->destroy(dev);
return ret;
}
cd->fd = ret;
return 0;
}
static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
{
switch (arg) {
case KVM_CAP_USER_MEMORY:
case KVM_CAP_USER_MEMORY2:
case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
case KVM_CAP_JOIN_MEMORY_REGIONS_WORKS:
case KVM_CAP_INTERNAL_ERROR_DATA:
#ifdef CONFIG_HAVE_KVM_MSI
case KVM_CAP_SIGNAL_MSI:
#endif
#ifdef CONFIG_HAVE_KVM_IRQCHIP
case KVM_CAP_IRQFD:
#endif
case KVM_CAP_IOEVENTFD_ANY_LENGTH:
case KVM_CAP_CHECK_EXTENSION_VM:
case KVM_CAP_ENABLE_CAP_VM:
case KVM_CAP_HALT_POLL:
return 1;
#ifdef CONFIG_KVM_MMIO
case KVM_CAP_COALESCED_MMIO:
return KVM_COALESCED_MMIO_PAGE_OFFSET;
case KVM_CAP_COALESCED_PIO:
return 1;
#endif
#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
case KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2:
return KVM_DIRTY_LOG_MANUAL_CAPS;
#endif
#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
case KVM_CAP_IRQ_ROUTING:
return KVM_MAX_IRQ_ROUTES;
#endif
#if KVM_MAX_NR_ADDRESS_SPACES > 1
case KVM_CAP_MULTI_ADDRESS_SPACE:
if (kvm)
return kvm_arch_nr_memslot_as_ids(kvm);
return KVM_MAX_NR_ADDRESS_SPACES;
#endif
case KVM_CAP_NR_MEMSLOTS:
return KVM_USER_MEM_SLOTS;
case KVM_CAP_DIRTY_LOG_RING:
#ifdef CONFIG_HAVE_KVM_DIRTY_RING_TSO
return KVM_DIRTY_RING_MAX_ENTRIES * sizeof(struct kvm_dirty_gfn);
#else
return 0;
#endif
case KVM_CAP_DIRTY_LOG_RING_ACQ_REL:
#ifdef CONFIG_HAVE_KVM_DIRTY_RING_ACQ_REL
return KVM_DIRTY_RING_MAX_ENTRIES * sizeof(struct kvm_dirty_gfn);
#else
return 0;
#endif
#ifdef CONFIG_NEED_KVM_DIRTY_RING_WITH_BITMAP
case KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP:
#endif
case KVM_CAP_BINARY_STATS_FD:
case KVM_CAP_SYSTEM_EVENT_DATA:
case KVM_CAP_DEVICE_CTRL:
return 1;
#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
case KVM_CAP_MEMORY_ATTRIBUTES:
return kvm_supported_mem_attributes(kvm);
#endif
#ifdef CONFIG_KVM_GUEST_MEMFD
case KVM_CAP_GUEST_MEMFD:
return 1;
case KVM_CAP_GUEST_MEMFD_MMAP:
return !kvm || kvm_arch_supports_gmem_mmap(kvm);
#endif
default:
break;
}
return kvm_vm_ioctl_check_extension(kvm, arg);
}
static int kvm_vm_ioctl_enable_dirty_log_ring(struct kvm *kvm, u32 size)
{
int r;
if (!KVM_DIRTY_LOG_PAGE_OFFSET)
return -EINVAL;
/* the size should be power of 2 */
if (!size || (size & (size - 1)))
return -EINVAL;
/* Should be bigger to keep the reserved entries, or a page */
if (size < kvm_dirty_ring_get_rsvd_entries(kvm) *
sizeof(struct kvm_dirty_gfn) || size < PAGE_SIZE)
return -EINVAL;
if (size > KVM_DIRTY_RING_MAX_ENTRIES *
sizeof(struct kvm_dirty_gfn))
return -E2BIG;
/* We only allow it to set once */
if (kvm->dirty_ring_size)
return -EINVAL;
mutex_lock(&kvm->lock);
if (kvm->created_vcpus) {
/* We don't allow to change this value after vcpu created */
r = -EINVAL;
} else {
kvm->dirty_ring_size = size;
r = 0;
}
mutex_unlock(&kvm->lock);
return r;
}
static int kvm_vm_ioctl_reset_dirty_pages(struct kvm *kvm)
{
unsigned long i;
struct kvm_vcpu *vcpu;
int cleared = 0, r;
if (!kvm->dirty_ring_size)
return -EINVAL;
mutex_lock(&kvm->slots_lock);
kvm_for_each_vcpu(i, vcpu, kvm) {
r = kvm_dirty_ring_reset(vcpu->kvm, &vcpu->dirty_ring, &cleared);
if (r)
break;
}
mutex_unlock(&kvm->slots_lock);
if (cleared)
kvm_flush_remote_tlbs(kvm);
return cleared;
}
int __attribute__((weak)) kvm_vm_ioctl_enable_cap(struct kvm *kvm,
struct kvm_enable_cap *cap)
{
return -EINVAL;
}
bool kvm_are_all_memslots_empty(struct kvm *kvm)
{
int i;
lockdep_assert_held(&kvm->slots_lock);
for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
if (!kvm_memslots_empty(__kvm_memslots(kvm, i)))
return false;
}
return true;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_are_all_memslots_empty);
static int kvm_vm_ioctl_enable_cap_generic(struct kvm *kvm,
struct kvm_enable_cap *cap)
{
switch (cap->cap) {
#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
case KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2: {
u64 allowed_options = KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE;
if (cap->args[0] & KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE)
allowed_options = KVM_DIRTY_LOG_MANUAL_CAPS;
if (cap->flags || (cap->args[0] & ~allowed_options))
return -EINVAL;
kvm->manual_dirty_log_protect = cap->args[0];
return 0;
}
#endif
case KVM_CAP_HALT_POLL: {
if (cap->flags || cap->args[0] != (unsigned int)cap->args[0])
return -EINVAL;
kvm->max_halt_poll_ns = cap->args[0];
/*
* Ensure kvm->override_halt_poll_ns does not become visible
* before kvm->max_halt_poll_ns.
*
* Pairs with the smp_rmb() in kvm_vcpu_max_halt_poll_ns().
*/
smp_wmb();
kvm->override_halt_poll_ns = true;
return 0;
}
case KVM_CAP_DIRTY_LOG_RING:
case KVM_CAP_DIRTY_LOG_RING_ACQ_REL:
if (!kvm_vm_ioctl_check_extension_generic(kvm, cap->cap))
return -EINVAL;
return kvm_vm_ioctl_enable_dirty_log_ring(kvm, cap->args[0]);
case KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP: {
int r = -EINVAL;
if (!IS_ENABLED(CONFIG_NEED_KVM_DIRTY_RING_WITH_BITMAP) ||
!kvm->dirty_ring_size || cap->flags)
return r;
mutex_lock(&kvm->slots_lock);
/*
* For simplicity, allow enabling ring+bitmap if and only if
* there are no memslots, e.g. to ensure all memslots allocate
* a bitmap after the capability is enabled.
*/
if (kvm_are_all_memslots_empty(kvm)) {
kvm->dirty_ring_with_bitmap = true;
r = 0;
}
mutex_unlock(&kvm->slots_lock);
return r;
}
default:
return kvm_vm_ioctl_enable_cap(kvm, cap);
}
}
static ssize_t kvm_vm_stats_read(struct file *file, char __user *user_buffer,
size_t size, loff_t *offset)
{
struct kvm *kvm = file->private_data;
return kvm_stats_read(kvm->stats_id, &kvm_vm_stats_header,
&kvm_vm_stats_desc[0], &kvm->stat,
sizeof(kvm->stat), user_buffer, size, offset);
}
static int kvm_vm_stats_release(struct inode *inode, struct file *file)
{
struct kvm *kvm = file->private_data;
kvm_put_kvm(kvm);
return 0;
}
static const struct file_operations kvm_vm_stats_fops = {
.owner = THIS_MODULE,
.read = kvm_vm_stats_read,
.release = kvm_vm_stats_release,
.llseek = noop_llseek,
};
static int kvm_vm_ioctl_get_stats_fd(struct kvm *kvm)
{
int fd;
struct file *file;
fd = get_unused_fd_flags(O_CLOEXEC);
if (fd < 0)
return fd;
file = anon_inode_getfile_fmode("kvm-vm-stats",
&kvm_vm_stats_fops, kvm, O_RDONLY, FMODE_PREAD);
if (IS_ERR(file)) {
put_unused_fd(fd);
return PTR_ERR(file);
}
kvm_get_kvm(kvm);
fd_install(fd, file);
return fd;
}
#define SANITY_CHECK_MEM_REGION_FIELD(field) \
do { \
BUILD_BUG_ON(offsetof(struct kvm_userspace_memory_region, field) != \
offsetof(struct kvm_userspace_memory_region2, field)); \
BUILD_BUG_ON(sizeof_field(struct kvm_userspace_memory_region, field) != \
sizeof_field(struct kvm_userspace_memory_region2, field)); \
} while (0)
static long kvm_vm_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
struct kvm *kvm = filp->private_data;
void __user *argp = (void __user *)arg;
int r;
if (kvm->mm != current->mm || kvm->vm_dead)
return -EIO;
switch (ioctl) {
case KVM_CREATE_VCPU:
r = kvm_vm_ioctl_create_vcpu(kvm, arg);
break;
case KVM_ENABLE_CAP: {
struct kvm_enable_cap cap;
r = -EFAULT;
if (copy_from_user(&cap, argp, sizeof(cap)))
goto out;
r = kvm_vm_ioctl_enable_cap_generic(kvm, &cap);
break;
}
case KVM_SET_USER_MEMORY_REGION2:
case KVM_SET_USER_MEMORY_REGION: {
struct kvm_userspace_memory_region2 mem;
unsigned long size;
if (ioctl == KVM_SET_USER_MEMORY_REGION) {
/*
* Fields beyond struct kvm_userspace_memory_region shouldn't be
* accessed, but avoid leaking kernel memory in case of a bug.
*/
memset(&mem, 0, sizeof(mem));
size = sizeof(struct kvm_userspace_memory_region);
} else {
size = sizeof(struct kvm_userspace_memory_region2);
}
/* Ensure the common parts of the two structs are identical. */
SANITY_CHECK_MEM_REGION_FIELD(slot);
SANITY_CHECK_MEM_REGION_FIELD(flags);
SANITY_CHECK_MEM_REGION_FIELD(guest_phys_addr);
SANITY_CHECK_MEM_REGION_FIELD(memory_size);
SANITY_CHECK_MEM_REGION_FIELD(userspace_addr);
r = -EFAULT;
if (copy_from_user(&mem, argp, size))
goto out;
r = -EINVAL;
if (ioctl == KVM_SET_USER_MEMORY_REGION &&
(mem.flags & ~KVM_SET_USER_MEMORY_REGION_V1_FLAGS))
goto out;
r = kvm_vm_ioctl_set_memory_region(kvm, &mem);
break;
}
case KVM_GET_DIRTY_LOG: {
struct kvm_dirty_log log;
r = -EFAULT;
if (copy_from_user(&log, argp, sizeof(log)))
goto out;
r = kvm_vm_ioctl_get_dirty_log(kvm, &log);
break;
}
#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
case KVM_CLEAR_DIRTY_LOG: {
struct kvm_clear_dirty_log log;
r = -EFAULT;
if (copy_from_user(&log, argp, sizeof(log)))
goto out;
r = kvm_vm_ioctl_clear_dirty_log(kvm, &log);
break;
}
#endif
#ifdef CONFIG_KVM_MMIO
case KVM_REGISTER_COALESCED_MMIO: {
struct kvm_coalesced_mmio_zone zone;
r = -EFAULT;
if (copy_from_user(&zone, argp, sizeof(zone)))
goto out;
r = kvm_vm_ioctl_register_coalesced_mmio(kvm, &zone);
break;
}
case KVM_UNREGISTER_COALESCED_MMIO: {
struct kvm_coalesced_mmio_zone zone;
r = -EFAULT;
if (copy_from_user(&zone, argp, sizeof(zone)))
goto out;
r = kvm_vm_ioctl_unregister_coalesced_mmio(kvm, &zone);
break;
}
#endif
case KVM_IRQFD: {
struct kvm_irqfd data;
r = -EFAULT;
if (copy_from_user(&data, argp, sizeof(data)))
goto out;
r = kvm_irqfd(kvm, &data);
break;
}
case KVM_IOEVENTFD: {
struct kvm_ioeventfd data;
r = -EFAULT;
if (copy_from_user(&data, argp, sizeof(data)))
goto out;
r = kvm_ioeventfd(kvm, &data);
break;
}
#ifdef CONFIG_HAVE_KVM_MSI
case KVM_SIGNAL_MSI: {
struct kvm_msi msi;
r = -EFAULT;
if (copy_from_user(&msi, argp, sizeof(msi)))
goto out;
r = kvm_send_userspace_msi(kvm, &msi);
break;
}
#endif
#ifdef __KVM_HAVE_IRQ_LINE
case KVM_IRQ_LINE_STATUS:
case KVM_IRQ_LINE: {
struct kvm_irq_level irq_event;
r = -EFAULT;
if (copy_from_user(&irq_event, argp, sizeof(irq_event)))
goto out;
r = kvm_vm_ioctl_irq_line(kvm, &irq_event,
ioctl == KVM_IRQ_LINE_STATUS);
if (r)
goto out;
r = -EFAULT;
if (ioctl == KVM_IRQ_LINE_STATUS) {
if (copy_to_user(argp, &irq_event, sizeof(irq_event)))
goto out;
}
r = 0;
break;
}
#endif
#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
case KVM_SET_GSI_ROUTING: {
struct kvm_irq_routing routing;
struct kvm_irq_routing __user *urouting;
struct kvm_irq_routing_entry *entries = NULL;
r = -EFAULT;
if (copy_from_user(&routing, argp, sizeof(routing)))
goto out;
r = -EINVAL;
if (!kvm_arch_can_set_irq_routing(kvm))
goto out;
if (routing.nr > KVM_MAX_IRQ_ROUTES)
goto out;
if (routing.flags)
goto out;
if (routing.nr) {
urouting = argp;
entries = vmemdup_array_user(urouting->entries,
routing.nr, sizeof(*entries));
if (IS_ERR(entries)) {
r = PTR_ERR(entries);
goto out;
}
}
r = kvm_set_irq_routing(kvm, entries, routing.nr,
routing.flags);
kvfree(entries);
break;
}
#endif /* CONFIG_HAVE_KVM_IRQ_ROUTING */
#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
case KVM_SET_MEMORY_ATTRIBUTES: {
struct kvm_memory_attributes attrs;
r = -EFAULT;
if (copy_from_user(&attrs, argp, sizeof(attrs)))
goto out;
r = kvm_vm_ioctl_set_mem_attributes(kvm, &attrs);
break;
}
#endif /* CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES */
case KVM_CREATE_DEVICE: {
struct kvm_create_device cd;
r = -EFAULT;
if (copy_from_user(&cd, argp, sizeof(cd)))
goto out;
r = kvm_ioctl_create_device(kvm, &cd);
if (r)
goto out;
r = -EFAULT;
if (copy_to_user(argp, &cd, sizeof(cd)))
goto out;
r = 0;
break;
}
case KVM_CHECK_EXTENSION:
r = kvm_vm_ioctl_check_extension_generic(kvm, arg);
break;
case KVM_RESET_DIRTY_RINGS:
r = kvm_vm_ioctl_reset_dirty_pages(kvm);
break;
case KVM_GET_STATS_FD:
r = kvm_vm_ioctl_get_stats_fd(kvm);
break;
#ifdef CONFIG_KVM_GUEST_MEMFD
case KVM_CREATE_GUEST_MEMFD: {
struct kvm_create_guest_memfd guest_memfd;
r = -EFAULT;
if (copy_from_user(&guest_memfd, argp, sizeof(guest_memfd)))
goto out;
r = kvm_gmem_create(kvm, &guest_memfd);
break;
}
#endif
default:
r = kvm_arch_vm_ioctl(filp, ioctl, arg);
}
out:
return r;
}
#ifdef CONFIG_KVM_COMPAT
struct compat_kvm_dirty_log {
__u32 slot;
__u32 padding1;
union {
compat_uptr_t dirty_bitmap; /* one bit per page */
__u64 padding2;
};
};
struct compat_kvm_clear_dirty_log {
__u32 slot;
__u32 num_pages;
__u64 first_page;
union {
compat_uptr_t dirty_bitmap; /* one bit per page */
__u64 padding2;
};
};
long __weak kvm_arch_vm_compat_ioctl(struct file *filp, unsigned int ioctl,
unsigned long arg)
{
return -ENOTTY;
}
static long kvm_vm_compat_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
struct kvm *kvm = filp->private_data;
int r;
if (kvm->mm != current->mm || kvm->vm_dead)
return -EIO;
r = kvm_arch_vm_compat_ioctl(filp, ioctl, arg);
if (r != -ENOTTY)
return r;
switch (ioctl) {
#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
case KVM_CLEAR_DIRTY_LOG: {
struct compat_kvm_clear_dirty_log compat_log;
struct kvm_clear_dirty_log log;
if (copy_from_user(&compat_log, (void __user *)arg,
sizeof(compat_log)))
return -EFAULT;
log.slot = compat_log.slot;
log.num_pages = compat_log.num_pages;
log.first_page = compat_log.first_page;
log.padding2 = compat_log.padding2;
log.dirty_bitmap = compat_ptr(compat_log.dirty_bitmap);
r = kvm_vm_ioctl_clear_dirty_log(kvm, &log);
break;
}
#endif
case KVM_GET_DIRTY_LOG: {
struct compat_kvm_dirty_log compat_log;
struct kvm_dirty_log log;
if (copy_from_user(&compat_log, (void __user *)arg,
sizeof(compat_log)))
return -EFAULT;
log.slot = compat_log.slot;
log.padding1 = compat_log.padding1;
log.padding2 = compat_log.padding2;
log.dirty_bitmap = compat_ptr(compat_log.dirty_bitmap);
r = kvm_vm_ioctl_get_dirty_log(kvm, &log);
break;
}
default:
r = kvm_vm_ioctl(filp, ioctl, arg);
}
return r;
}
#endif
static struct file_operations kvm_vm_fops = {
.release = kvm_vm_release,
.unlocked_ioctl = kvm_vm_ioctl,
.llseek = noop_llseek,
KVM_COMPAT(kvm_vm_compat_ioctl),
};
bool file_is_kvm(struct file *file)
{
return file && file->f_op == &kvm_vm_fops;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(file_is_kvm);
static int kvm_dev_ioctl_create_vm(unsigned long type)
{
char fdname[ITOA_MAX_LEN + 1];
int r, fd;
struct kvm *kvm;
struct file *file;
fd = get_unused_fd_flags(O_CLOEXEC);
if (fd < 0)
return fd;
snprintf(fdname, sizeof(fdname), "%d", fd);
kvm = kvm_create_vm(type, fdname);
if (IS_ERR(kvm)) {
r = PTR_ERR(kvm);
goto put_fd;
}
file = anon_inode_getfile("kvm-vm", &kvm_vm_fops, kvm, O_RDWR);
if (IS_ERR(file)) {
r = PTR_ERR(file);
goto put_kvm;
}
/*
* Don't call kvm_put_kvm anymore at this point; file->f_op is
* already set, with ->release() being kvm_vm_release(). In error
* cases it will be called by the final fput(file) and will take
* care of doing kvm_put_kvm(kvm).
*/
kvm_uevent_notify_change(KVM_EVENT_CREATE_VM, kvm);
fd_install(fd, file);
return fd;
put_kvm:
kvm_put_kvm(kvm);
put_fd:
put_unused_fd(fd);
return r;
}
static long kvm_dev_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
int r = -EINVAL;
switch (ioctl) {
case KVM_GET_API_VERSION:
if (arg)
goto out;
r = KVM_API_VERSION;
break;
case KVM_CREATE_VM:
r = kvm_dev_ioctl_create_vm(arg);
break;
case KVM_CHECK_EXTENSION:
r = kvm_vm_ioctl_check_extension_generic(NULL, arg);
break;
case KVM_GET_VCPU_MMAP_SIZE:
if (arg)
goto out;
r = PAGE_SIZE; /* struct kvm_run */
#ifdef CONFIG_X86
r += PAGE_SIZE; /* pio data page */
#endif
#ifdef CONFIG_KVM_MMIO
r += PAGE_SIZE; /* coalesced mmio ring page */
#endif
break;
default:
return kvm_arch_dev_ioctl(filp, ioctl, arg);
}
out:
return r;
}
static struct file_operations kvm_chardev_ops = {
.unlocked_ioctl = kvm_dev_ioctl,
.llseek = noop_llseek,
KVM_COMPAT(kvm_dev_ioctl),
};
static struct miscdevice kvm_dev = {
KVM_MINOR,
"kvm",
&kvm_chardev_ops,
};
#ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING
bool enable_virt_at_load = true;
module_param(enable_virt_at_load, bool, 0444);
EXPORT_SYMBOL_FOR_KVM_INTERNAL(enable_virt_at_load);
__visible bool kvm_rebooting;
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_rebooting);
static DEFINE_PER_CPU(bool, virtualization_enabled);
static DEFINE_MUTEX(kvm_usage_lock);
static int kvm_usage_count;
__weak void kvm_arch_enable_virtualization(void)
{
}
__weak void kvm_arch_disable_virtualization(void)
{
}
static int kvm_enable_virtualization_cpu(void)
{
if (__this_cpu_read(virtualization_enabled))
return 0;
if (kvm_arch_enable_virtualization_cpu()) {
pr_info("kvm: enabling virtualization on CPU%d failed\n",
raw_smp_processor_id());
return -EIO;
}
__this_cpu_write(virtualization_enabled, true);
return 0;
}
static int kvm_online_cpu(unsigned int cpu)
{
/*
* Abort the CPU online process if hardware virtualization cannot
* be enabled. Otherwise running VMs would encounter unrecoverable
* errors when scheduled to this CPU.
*/
return kvm_enable_virtualization_cpu();
}
static void kvm_disable_virtualization_cpu(void *ign)
{
if (!__this_cpu_read(virtualization_enabled))
return;
kvm_arch_disable_virtualization_cpu();
__this_cpu_write(virtualization_enabled, false);
}
static int kvm_offline_cpu(unsigned int cpu)
{
kvm_disable_virtualization_cpu(NULL);
return 0;
}
static void kvm_shutdown(void)
{
/*
* Disable hardware virtualization and set kvm_rebooting to indicate
* that KVM has asynchronously disabled hardware virtualization, i.e.
* that relevant errors and exceptions aren't entirely unexpected.
* Some flavors of hardware virtualization need to be disabled before
* transferring control to firmware (to perform shutdown/reboot), e.g.
* on x86, virtualization can block INIT interrupts, which are used by
* firmware to pull APs back under firmware control. Note, this path
* is used for both shutdown and reboot scenarios, i.e. neither name is
* 100% comprehensive.
*/
pr_info("kvm: exiting hardware virtualization\n");
kvm_rebooting = true;
on_each_cpu(kvm_disable_virtualization_cpu, NULL, 1);
}
static int kvm_suspend(void)
{
/*
* Secondary CPUs and CPU hotplug are disabled across the suspend/resume
* callbacks, i.e. no need to acquire kvm_usage_lock to ensure the usage
* count is stable. Assert that kvm_usage_lock is not held to ensure
* the system isn't suspended while KVM is enabling hardware. Hardware
* enabling can be preempted, but the task cannot be frozen until it has
* dropped all locks (userspace tasks are frozen via a fake signal).
*/
lockdep_assert_not_held(&kvm_usage_lock);
lockdep_assert_irqs_disabled();
kvm_disable_virtualization_cpu(NULL);
return 0;
}
static void kvm_resume(void)
{
lockdep_assert_not_held(&kvm_usage_lock);
lockdep_assert_irqs_disabled();
WARN_ON_ONCE(kvm_enable_virtualization_cpu());
}
static struct syscore_ops kvm_syscore_ops = {
.suspend = kvm_suspend,
.resume = kvm_resume,
.shutdown = kvm_shutdown,
};
int kvm_enable_virtualization(void)
{
int r;
guard(mutex)(&kvm_usage_lock);
if (kvm_usage_count++)
return 0;
kvm_arch_enable_virtualization();
r = cpuhp_setup_state(CPUHP_AP_KVM_ONLINE, "kvm/cpu:online",
kvm_online_cpu, kvm_offline_cpu);
if (r)
goto err_cpuhp;
register_syscore_ops(&kvm_syscore_ops);
/*
* Undo virtualization enabling and bail if the system is going down.
* If userspace initiated a forced reboot, e.g. reboot -f, then it's
* possible for an in-flight operation to enable virtualization after
* syscore_shutdown() is called, i.e. without kvm_shutdown() being
* invoked. Note, this relies on system_state being set _before_
* kvm_shutdown(), e.g. to ensure either kvm_shutdown() is invoked
* or this CPU observes the impending shutdown. Which is why KVM uses
* a syscore ops hook instead of registering a dedicated reboot
* notifier (the latter runs before system_state is updated).
*/
if (system_state == SYSTEM_HALT || system_state == SYSTEM_POWER_OFF ||
system_state == SYSTEM_RESTART) {
r = -EBUSY;
goto err_rebooting;
}
return 0;
err_rebooting:
unregister_syscore_ops(&kvm_syscore_ops);
cpuhp_remove_state(CPUHP_AP_KVM_ONLINE);
err_cpuhp:
kvm_arch_disable_virtualization();
--kvm_usage_count;
return r;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_enable_virtualization);
void kvm_disable_virtualization(void)
{
guard(mutex)(&kvm_usage_lock);
if (--kvm_usage_count)
return;
unregister_syscore_ops(&kvm_syscore_ops);
cpuhp_remove_state(CPUHP_AP_KVM_ONLINE);
kvm_arch_disable_virtualization();
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_disable_virtualization);
static int kvm_init_virtualization(void)
{
if (enable_virt_at_load)
return kvm_enable_virtualization();
return 0;
}
static void kvm_uninit_virtualization(void)
{
if (enable_virt_at_load)
kvm_disable_virtualization();
}
#else /* CONFIG_KVM_GENERIC_HARDWARE_ENABLING */
static int kvm_init_virtualization(void)
{
return 0;
}
static void kvm_uninit_virtualization(void)
{
}
#endif /* CONFIG_KVM_GENERIC_HARDWARE_ENABLING */
static void kvm_iodevice_destructor(struct kvm_io_device *dev)
{
if (dev->ops->destructor)
dev->ops->destructor(dev);
}
static void kvm_io_bus_destroy(struct kvm_io_bus *bus)
{
int i;
for (i = 0; i < bus->dev_count; i++) {
struct kvm_io_device *pos = bus->range[i].dev;
kvm_iodevice_destructor(pos);
}
kfree(bus);
}
static inline int kvm_io_bus_cmp(const struct kvm_io_range *r1,
const struct kvm_io_range *r2)
{
gpa_t addr1 = r1->addr;
gpa_t addr2 = r2->addr;
if (addr1 < addr2)
return -1;
/* If r2->len == 0, match the exact address. If r2->len != 0,
* accept any overlapping write. Any order is acceptable for
* overlapping ranges, because kvm_io_bus_get_first_dev ensures
* we process all of them.
*/
if (r2->len) {
addr1 += r1->len;
addr2 += r2->len;
}
if (addr1 > addr2)
return 1;
return 0;
}
static int kvm_io_bus_sort_cmp(const void *p1, const void *p2)
{
return kvm_io_bus_cmp(p1, p2);
}
static int kvm_io_bus_get_first_dev(struct kvm_io_bus *bus,
gpa_t addr, int len)
{
struct kvm_io_range *range, key;
int off;
key = (struct kvm_io_range) {
.addr = addr,
.len = len,
};
range = bsearch(&key, bus->range, bus->dev_count,
sizeof(struct kvm_io_range), kvm_io_bus_sort_cmp);
if (range == NULL)
return -ENOENT;
off = range - bus->range;
while (off > 0 && kvm_io_bus_cmp(&key, &bus->range[off-1]) == 0)
off--;
return off;
}
static int __kvm_io_bus_write(struct kvm_vcpu *vcpu, struct kvm_io_bus *bus,
struct kvm_io_range *range, const void *val)
{
int idx;
idx = kvm_io_bus_get_first_dev(bus, range->addr, range->len);
if (idx < 0)
return -EOPNOTSUPP;
while (idx < bus->dev_count &&
kvm_io_bus_cmp(range, &bus->range[idx]) == 0) {
if (!kvm_iodevice_write(vcpu, bus->range[idx].dev, range->addr,
range->len, val))
return idx;
idx++;
}
return -EOPNOTSUPP;
}
static struct kvm_io_bus *kvm_get_bus_srcu(struct kvm *kvm, enum kvm_bus idx)
{
/*
* Ensure that any updates to kvm_buses[] observed by the previous vCPU
* machine instruction are also visible to the vCPU machine instruction
* that triggered this call.
*/
smp_mb__after_srcu_read_lock();
return srcu_dereference(kvm->buses[idx], &kvm->srcu);
}
int kvm_io_bus_write(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr,
int len, const void *val)
{
struct kvm_io_bus *bus;
struct kvm_io_range range;
int r;
range = (struct kvm_io_range) {
.addr = addr,
.len = len,
};
bus = kvm_get_bus_srcu(vcpu->kvm, bus_idx);
if (!bus)
return -ENOMEM;
r = __kvm_io_bus_write(vcpu, bus, &range, val);
return r < 0 ? r : 0;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_io_bus_write);
int kvm_io_bus_write_cookie(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx,
gpa_t addr, int len, const void *val, long cookie)
{
struct kvm_io_bus *bus;
struct kvm_io_range range;
range = (struct kvm_io_range) {
.addr = addr,
.len = len,
};
bus = kvm_get_bus_srcu(vcpu->kvm, bus_idx);
if (!bus)
return -ENOMEM;
/* First try the device referenced by cookie. */
if ((cookie >= 0) && (cookie < bus->dev_count) &&
(kvm_io_bus_cmp(&range, &bus->range[cookie]) == 0))
if (!kvm_iodevice_write(vcpu, bus->range[cookie].dev, addr, len,
val))
return cookie;
/*
* cookie contained garbage; fall back to search and return the
* correct cookie value.
*/
return __kvm_io_bus_write(vcpu, bus, &range, val);
}
static int __kvm_io_bus_read(struct kvm_vcpu *vcpu, struct kvm_io_bus *bus,
struct kvm_io_range *range, void *val)
{
int idx;
idx = kvm_io_bus_get_first_dev(bus, range->addr, range->len);
if (idx < 0)
return -EOPNOTSUPP;
while (idx < bus->dev_count &&
kvm_io_bus_cmp(range, &bus->range[idx]) == 0) {
if (!kvm_iodevice_read(vcpu, bus->range[idx].dev, range->addr,
range->len, val))
return idx;
idx++;
}
return -EOPNOTSUPP;
}
int kvm_io_bus_read(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr,
int len, void *val)
{
struct kvm_io_bus *bus;
struct kvm_io_range range;
int r;
range = (struct kvm_io_range) {
.addr = addr,
.len = len,
};
bus = kvm_get_bus_srcu(vcpu->kvm, bus_idx);
if (!bus)
return -ENOMEM;
r = __kvm_io_bus_read(vcpu, bus, &range, val);
return r < 0 ? r : 0;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_io_bus_read);
static void __free_bus(struct rcu_head *rcu)
{
struct kvm_io_bus *bus = container_of(rcu, struct kvm_io_bus, rcu);
kfree(bus);
}
int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
int len, struct kvm_io_device *dev)
{
int i;
struct kvm_io_bus *new_bus, *bus;
struct kvm_io_range range;
lockdep_assert_held(&kvm->slots_lock);
bus = kvm_get_bus(kvm, bus_idx);
if (!bus)
return -ENOMEM;
/* exclude ioeventfd which is limited by maximum fd */
if (bus->dev_count - bus->ioeventfd_count > NR_IOBUS_DEVS - 1)
return -ENOSPC;
new_bus = kmalloc(struct_size(bus, range, bus->dev_count + 1),
GFP_KERNEL_ACCOUNT);
if (!new_bus)
return -ENOMEM;
range = (struct kvm_io_range) {
.addr = addr,
.len = len,
.dev = dev,
};
for (i = 0; i < bus->dev_count; i++)
if (kvm_io_bus_cmp(&bus->range[i], &range) > 0)
break;
memcpy(new_bus, bus, sizeof(*bus) + i * sizeof(struct kvm_io_range));
new_bus->dev_count++;
new_bus->range[i] = range;
memcpy(new_bus->range + i + 1, bus->range + i,
(bus->dev_count - i) * sizeof(struct kvm_io_range));
rcu_assign_pointer(kvm->buses[bus_idx], new_bus);
call_srcu(&kvm->srcu, &bus->rcu, __free_bus);
return 0;
}
int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
struct kvm_io_device *dev)
{
int i;
struct kvm_io_bus *new_bus, *bus;
lockdep_assert_held(&kvm->slots_lock);
bus = kvm_get_bus(kvm, bus_idx);
if (!bus)
return 0;
for (i = 0; i < bus->dev_count; i++) {
if (bus->range[i].dev == dev) {
break;
}
}
if (i == bus->dev_count)
return 0;
new_bus = kmalloc(struct_size(bus, range, bus->dev_count - 1),
GFP_KERNEL_ACCOUNT);
if (new_bus) {
memcpy(new_bus, bus, struct_size(bus, range, i));
new_bus->dev_count--;
memcpy(new_bus->range + i, bus->range + i + 1,
flex_array_size(new_bus, range, new_bus->dev_count - i));
}
rcu_assign_pointer(kvm->buses[bus_idx], new_bus);
synchronize_srcu_expedited(&kvm->srcu);
/*
* If NULL bus is installed, destroy the old bus, including all the
* attached devices. Otherwise, destroy the caller's device only.
*/
if (!new_bus) {
pr_err("kvm: failed to shrink bus, removing it completely\n");
kvm_io_bus_destroy(bus);
return -ENOMEM;
}
kvm_iodevice_destructor(dev);
kfree(bus);
return 0;
}
struct kvm_io_device *kvm_io_bus_get_dev(struct kvm *kvm, enum kvm_bus bus_idx,
gpa_t addr)
{
struct kvm_io_bus *bus;
int dev_idx, srcu_idx;
struct kvm_io_device *iodev = NULL;
srcu_idx = srcu_read_lock(&kvm->srcu);
bus = kvm_get_bus_srcu(kvm, bus_idx);
if (!bus)
goto out_unlock;
dev_idx = kvm_io_bus_get_first_dev(bus, addr, 1);
if (dev_idx < 0)
goto out_unlock;
iodev = bus->range[dev_idx].dev;
out_unlock:
srcu_read_unlock(&kvm->srcu, srcu_idx);
return iodev;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_io_bus_get_dev);
static int kvm_debugfs_open(struct inode *inode, struct file *file,
int (*get)(void *, u64 *), int (*set)(void *, u64),
const char *fmt)
{
int ret;
struct kvm_stat_data *stat_data = inode->i_private;
/*
* The debugfs files are a reference to the kvm struct which
* is still valid when kvm_destroy_vm is called. kvm_get_kvm_safe
* avoids the race between open and the removal of the debugfs directory.
*/
if (!kvm_get_kvm_safe(stat_data->kvm))
return -ENOENT;
ret = simple_attr_open(inode, file, get,
kvm_stats_debugfs_mode(stat_data->desc) & 0222
? set : NULL, fmt);
if (ret)
kvm_put_kvm(stat_data->kvm);
return ret;
}
static int kvm_debugfs_release(struct inode *inode, struct file *file)
{
struct kvm_stat_data *stat_data = inode->i_private;
simple_attr_release(inode, file);
kvm_put_kvm(stat_data->kvm);
return 0;
}
static int kvm_get_stat_per_vm(struct kvm *kvm, size_t offset, u64 *val)
{
*val = *(u64 *)((void *)(&kvm->stat) + offset);
return 0;
}
static int kvm_clear_stat_per_vm(struct kvm *kvm, size_t offset)
{
*(u64 *)((void *)(&kvm->stat) + offset) = 0;
return 0;
}
static int kvm_get_stat_per_vcpu(struct kvm *kvm, size_t offset, u64 *val)
{
unsigned long i;
struct kvm_vcpu *vcpu;
*val = 0;
kvm_for_each_vcpu(i, vcpu, kvm)
*val += *(u64 *)((void *)(&vcpu->stat) + offset);
return 0;
}
static int kvm_clear_stat_per_vcpu(struct kvm *kvm, size_t offset)
{
unsigned long i;
struct kvm_vcpu *vcpu;
kvm_for_each_vcpu(i, vcpu, kvm)
*(u64 *)((void *)(&vcpu->stat) + offset) = 0;
return 0;
}
static int kvm_stat_data_get(void *data, u64 *val)
{
int r = -EFAULT;
struct kvm_stat_data *stat_data = data;
switch (stat_data->kind) {
case KVM_STAT_VM:
r = kvm_get_stat_per_vm(stat_data->kvm,
stat_data->desc->desc.offset, val);
break;
case KVM_STAT_VCPU:
r = kvm_get_stat_per_vcpu(stat_data->kvm,
stat_data->desc->desc.offset, val);
break;
}
return r;
}
static int kvm_stat_data_clear(void *data, u64 val)
{
int r = -EFAULT;
struct kvm_stat_data *stat_data = data;
if (val)
return -EINVAL;
switch (stat_data->kind) {
case KVM_STAT_VM:
r = kvm_clear_stat_per_vm(stat_data->kvm,
stat_data->desc->desc.offset);
break;
case KVM_STAT_VCPU:
r = kvm_clear_stat_per_vcpu(stat_data->kvm,
stat_data->desc->desc.offset);
break;
}
return r;
}
static int kvm_stat_data_open(struct inode *inode, struct file *file)
{
__simple_attr_check_format("%llu\n", 0ull);
return kvm_debugfs_open(inode, file, kvm_stat_data_get,
kvm_stat_data_clear, "%llu\n");
}
static const struct file_operations stat_fops_per_vm = {
.owner = THIS_MODULE,
.open = kvm_stat_data_open,
.release = kvm_debugfs_release,
.read = simple_attr_read,
.write = simple_attr_write,
};
static int vm_stat_get(void *_offset, u64 *val)
{
unsigned offset = (long)_offset;
struct kvm *kvm;
u64 tmp_val;
*val = 0;
mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
kvm_get_stat_per_vm(kvm, offset, &tmp_val);
*val += tmp_val;
}
mutex_unlock(&kvm_lock);
return 0;
}
static int vm_stat_clear(void *_offset, u64 val)
{
unsigned offset = (long)_offset;
struct kvm *kvm;
if (val)
return -EINVAL;
mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
kvm_clear_stat_per_vm(kvm, offset);
}
mutex_unlock(&kvm_lock);
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(vm_stat_fops, vm_stat_get, vm_stat_clear, "%llu\n");
DEFINE_SIMPLE_ATTRIBUTE(vm_stat_readonly_fops, vm_stat_get, NULL, "%llu\n");
static int vcpu_stat_get(void *_offset, u64 *val)
{
unsigned offset = (long)_offset;
struct kvm *kvm;
u64 tmp_val;
*val = 0;
mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
kvm_get_stat_per_vcpu(kvm, offset, &tmp_val);
*val += tmp_val;
}
mutex_unlock(&kvm_lock);
return 0;
}
static int vcpu_stat_clear(void *_offset, u64 val)
{
unsigned offset = (long)_offset;
struct kvm *kvm;
if (val)
return -EINVAL;
mutex_lock(&kvm_lock);
list_for_each_entry(kvm, &vm_list, vm_list) {
kvm_clear_stat_per_vcpu(kvm, offset);
}
mutex_unlock(&kvm_lock);
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(vcpu_stat_fops, vcpu_stat_get, vcpu_stat_clear,
"%llu\n");
DEFINE_SIMPLE_ATTRIBUTE(vcpu_stat_readonly_fops, vcpu_stat_get, NULL, "%llu\n");
static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm)
{
struct kobj_uevent_env *env;
unsigned long long created, active;
if (!kvm_dev.this_device || !kvm)
return;
mutex_lock(&kvm_lock);
if (type == KVM_EVENT_CREATE_VM) {
kvm_createvm_count++;
kvm_active_vms++;
} else if (type == KVM_EVENT_DESTROY_VM) {
kvm_active_vms--;
}
created = kvm_createvm_count;
active = kvm_active_vms;
mutex_unlock(&kvm_lock);
env = kzalloc(sizeof(*env), GFP_KERNEL);
if (!env)
return;
add_uevent_var(env, "CREATED=%llu", created);
add_uevent_var(env, "COUNT=%llu", active);
if (type == KVM_EVENT_CREATE_VM) {
add_uevent_var(env, "EVENT=create");
kvm->userspace_pid = task_pid_nr(current);
} else if (type == KVM_EVENT_DESTROY_VM) {
add_uevent_var(env, "EVENT=destroy");
}
add_uevent_var(env, "PID=%d", kvm->userspace_pid);
if (!IS_ERR(kvm->debugfs_dentry)) {
char *tmp, *p = kmalloc(PATH_MAX, GFP_KERNEL);
if (p) {
tmp = dentry_path_raw(kvm->debugfs_dentry, p, PATH_MAX);
if (!IS_ERR(tmp))
add_uevent_var(env, "STATS_PATH=%s", tmp);
kfree(p);
}
}
/* no need for checks, since we are adding at most only 5 keys */
env->envp[env->envp_idx++] = NULL;
kobject_uevent_env(&kvm_dev.this_device->kobj, KOBJ_CHANGE, env->envp);
kfree(env);
}
static void kvm_init_debug(void)
{
const struct file_operations *fops;
const struct _kvm_stats_desc *pdesc;
int i;
kvm_debugfs_dir = debugfs_create_dir("kvm", NULL);
for (i = 0; i < kvm_vm_stats_header.num_desc; ++i) {
pdesc = &kvm_vm_stats_desc[i];
if (kvm_stats_debugfs_mode(pdesc) & 0222)
fops = &vm_stat_fops;
else
fops = &vm_stat_readonly_fops;
debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
kvm_debugfs_dir,
(void *)(long)pdesc->desc.offset, fops);
}
for (i = 0; i < kvm_vcpu_stats_header.num_desc; ++i) {
pdesc = &kvm_vcpu_stats_desc[i];
if (kvm_stats_debugfs_mode(pdesc) & 0222)
fops = &vcpu_stat_fops;
else
fops = &vcpu_stat_readonly_fops;
debugfs_create_file(pdesc->name, kvm_stats_debugfs_mode(pdesc),
kvm_debugfs_dir,
(void *)(long)pdesc->desc.offset, fops);
}
}
static inline
struct kvm_vcpu *preempt_notifier_to_vcpu(struct preempt_notifier *pn)
{
return container_of(pn, struct kvm_vcpu, preempt_notifier);
}
static void kvm_sched_in(struct preempt_notifier *pn, int cpu)
{
struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);
WRITE_ONCE(vcpu->preempted, false);
WRITE_ONCE(vcpu->ready, false);
__this_cpu_write(kvm_running_vcpu, vcpu);
kvm_arch_vcpu_load(vcpu, cpu);
WRITE_ONCE(vcpu->scheduled_out, false);
}
static void kvm_sched_out(struct preempt_notifier *pn,
struct task_struct *next)
{
struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn);
WRITE_ONCE(vcpu->scheduled_out, true);
if (task_is_runnable(current) && vcpu->wants_to_run) {
WRITE_ONCE(vcpu->preempted, true);
WRITE_ONCE(vcpu->ready, true);
}
kvm_arch_vcpu_put(vcpu);
__this_cpu_write(kvm_running_vcpu, NULL);
}
/**
* kvm_get_running_vcpu - get the vcpu running on the current CPU.
*
* We can disable preemption locally around accessing the per-CPU variable,
* and use the resolved vcpu pointer after enabling preemption again,
* because even if the current thread is migrated to another CPU, reading
* the per-CPU value later will give us the same value as we update the
* per-CPU variable in the preempt notifier handlers.
*/
struct kvm_vcpu *kvm_get_running_vcpu(void)
{
struct kvm_vcpu *vcpu;
preempt_disable();
vcpu = __this_cpu_read(kvm_running_vcpu);
preempt_enable();
return vcpu;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_get_running_vcpu);
/**
* kvm_get_running_vcpus - get the per-CPU array of currently running vcpus.
*/
struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void)
{
return &kvm_running_vcpu;
}
#ifdef CONFIG_GUEST_PERF_EVENTS
static unsigned int kvm_guest_state(void)
{
struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
unsigned int state;
if (!kvm_arch_pmi_in_guest(vcpu))
return 0;
state = PERF_GUEST_ACTIVE;
if (!kvm_arch_vcpu_in_kernel(vcpu))
state |= PERF_GUEST_USER;
return state;
}
static unsigned long kvm_guest_get_ip(void)
{
struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
/* Retrieving the IP must be guarded by a call to kvm_guest_state(). */
if (WARN_ON_ONCE(!kvm_arch_pmi_in_guest(vcpu)))
return 0;
return kvm_arch_vcpu_get_ip(vcpu);
}
static struct perf_guest_info_callbacks kvm_guest_cbs = {
.state = kvm_guest_state,
.get_ip = kvm_guest_get_ip,
.handle_intel_pt_intr = NULL,
};
void kvm_register_perf_callbacks(unsigned int (*pt_intr_handler)(void))
{
kvm_guest_cbs.handle_intel_pt_intr = pt_intr_handler;
perf_register_guest_info_callbacks(&kvm_guest_cbs);
}
void kvm_unregister_perf_callbacks(void)
{
perf_unregister_guest_info_callbacks(&kvm_guest_cbs);
}
#endif
int kvm_init(unsigned vcpu_size, unsigned vcpu_align, struct module *module)
{
int r;
int cpu;
/* A kmem cache lets us meet the alignment requirements of fx_save. */
if (!vcpu_align)
vcpu_align = __alignof__(struct kvm_vcpu);
kvm_vcpu_cache =
kmem_cache_create_usercopy("kvm_vcpu", vcpu_size, vcpu_align,
SLAB_ACCOUNT,
offsetof(struct kvm_vcpu, arch),
offsetofend(struct kvm_vcpu, stats_id)
- offsetof(struct kvm_vcpu, arch),
NULL);
if (!kvm_vcpu_cache)
return -ENOMEM;
for_each_possible_cpu(cpu) {
if (!alloc_cpumask_var_node(&per_cpu(cpu_kick_mask, cpu),
GFP_KERNEL, cpu_to_node(cpu))) {
r = -ENOMEM;
goto err_cpu_kick_mask;
}
}
r = kvm_irqfd_init();
if (r)
goto err_irqfd;
r = kvm_async_pf_init();
if (r)
goto err_async_pf;
kvm_chardev_ops.owner = module;
kvm_vm_fops.owner = module;
kvm_vcpu_fops.owner = module;
kvm_device_fops.owner = module;
kvm_preempt_ops.sched_in = kvm_sched_in;
kvm_preempt_ops.sched_out = kvm_sched_out;
kvm_init_debug();
r = kvm_vfio_ops_init();
if (WARN_ON_ONCE(r))
goto err_vfio;
kvm_gmem_init(module);
r = kvm_init_virtualization();
if (r)
goto err_virt;
/*
* Registration _must_ be the very last thing done, as this exposes
* /dev/kvm to userspace, i.e. all infrastructure must be setup!
*/
r = misc_register(&kvm_dev);
if (r) {
pr_err("kvm: misc device register failed\n");
goto err_register;
}
return 0;
err_register:
kvm_uninit_virtualization();
err_virt:
kvm_vfio_ops_exit();
err_vfio:
kvm_async_pf_deinit();
err_async_pf:
kvm_irqfd_exit();
err_irqfd:
err_cpu_kick_mask:
for_each_possible_cpu(cpu)
free_cpumask_var(per_cpu(cpu_kick_mask, cpu));
kmem_cache_destroy(kvm_vcpu_cache);
return r;
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_init);
void kvm_exit(void)
{
int cpu;
/*
* Note, unregistering /dev/kvm doesn't strictly need to come first,
* fops_get(), a.k.a. try_module_get(), prevents acquiring references
* to KVM while the module is being stopped.
*/
misc_deregister(&kvm_dev);
kvm_uninit_virtualization();
debugfs_remove_recursive(kvm_debugfs_dir);
for_each_possible_cpu(cpu)
free_cpumask_var(per_cpu(cpu_kick_mask, cpu));
kmem_cache_destroy(kvm_vcpu_cache);
kvm_vfio_ops_exit();
kvm_async_pf_deinit();
kvm_irqfd_exit();
}
EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_exit);