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kernel / pub / scm / linux / kernel / git / gregkh / tty / 02e5f74ef08d3e6afec438d571487d0d0cec3c48 / . / drivers / vhost / vhost.c
blob: 8570fdf2e14ab57806599847b0feff2a2c1c4201 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (C) 2009 Red Hat, Inc.
* Copyright (C) 2006 Rusty Russell IBM Corporation
*
* Author: Michael S. Tsirkin <mst@redhat.com>
*
* Inspiration, some code, and most witty comments come from
* Documentation/virtual/lguest/lguest.c, by Rusty Russell
*
* Generic code for virtio server in host kernel.
*/
#include <linux/eventfd.h>
#include <linux/vhost.h>
#include <linux/uio.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/file.h>
#include <linux/highmem.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/kthread.h>
#include <linux/cgroup.h>
#include <linux/module.h>
#include <linux/sort.h>
#include <linux/sched/mm.h>
#include <linux/sched/signal.h>
#include <linux/sched/vhost_task.h>
#include <linux/interval_tree_generic.h>
#include <linux/nospec.h>
#include <linux/kcov.h>
#include "vhost.h"
static ushort max_mem_regions = 64;
module_param(max_mem_regions, ushort, 0444);
MODULE_PARM_DESC(max_mem_regions,
"Maximum number of memory regions in memory map. (default: 64)");
static int max_iotlb_entries = 2048;
module_param(max_iotlb_entries, int, 0444);
MODULE_PARM_DESC(max_iotlb_entries,
"Maximum number of iotlb entries. (default: 2048)");
static bool fork_from_owner_default = VHOST_FORK_OWNER_TASK;
#ifdef CONFIG_VHOST_ENABLE_FORK_OWNER_CONTROL
module_param(fork_from_owner_default, bool, 0444);
MODULE_PARM_DESC(fork_from_owner_default,
"Set task mode as the default(default: Y)");
#endif
enum {
VHOST_MEMORY_F_LOG = 0x1,
};
#define vhost_used_event(vq) ((__virtio16 __user *)&vq->avail->ring[vq->num])
#define vhost_avail_event(vq) ((__virtio16 __user *)&vq->used->ring[vq->num])
#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
{
vq->user_be = !virtio_legacy_is_little_endian();
}
static void vhost_enable_cross_endian_big(struct vhost_virtqueue *vq)
{
vq->user_be = true;
}
static void vhost_enable_cross_endian_little(struct vhost_virtqueue *vq)
{
vq->user_be = false;
}
static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
{
struct vhost_vring_state s;
if (vq->private_data)
return -EBUSY;
if (copy_from_user(&s, argp, sizeof(s)))
return -EFAULT;
if (s.num != VHOST_VRING_LITTLE_ENDIAN &&
s.num != VHOST_VRING_BIG_ENDIAN)
return -EINVAL;
if (s.num == VHOST_VRING_BIG_ENDIAN)
vhost_enable_cross_endian_big(vq);
else
vhost_enable_cross_endian_little(vq);
return 0;
}
static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
int __user *argp)
{
struct vhost_vring_state s = {
.index = idx,
.num = vq->user_be
};
if (copy_to_user(argp, &s, sizeof(s)))
return -EFAULT;
return 0;
}
static void vhost_init_is_le(struct vhost_virtqueue *vq)
{
/* Note for legacy virtio: user_be is initialized at reset time
* according to the host endianness. If userspace does not set an
* explicit endianness, the default behavior is native endian, as
* expected by legacy virtio.
*/
vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1) || !vq->user_be;
}
#else
static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
{
}
static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
{
return -ENOIOCTLCMD;
}
static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
int __user *argp)
{
return -ENOIOCTLCMD;
}
static void vhost_init_is_le(struct vhost_virtqueue *vq)
{
vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1)
|| virtio_legacy_is_little_endian();
}
#endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
static void vhost_reset_is_le(struct vhost_virtqueue *vq)
{
vhost_init_is_le(vq);
}
struct vhost_flush_struct {
struct vhost_work work;
struct completion wait_event;
};
static void vhost_flush_work(struct vhost_work *work)
{
struct vhost_flush_struct *s;
s = container_of(work, struct vhost_flush_struct, work);
complete(&s->wait_event);
}
static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
poll_table *pt)
{
struct vhost_poll *poll;
poll = container_of(pt, struct vhost_poll, table);
poll->wqh = wqh;
add_wait_queue(wqh, &poll->wait);
}
static int vhost_poll_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync,
void *key)
{
struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait);
struct vhost_work *work = &poll->work;
if (!(key_to_poll(key) & poll->mask))
return 0;
if (!poll->dev->use_worker)
work->fn(work);
else
vhost_poll_queue(poll);
return 0;
}
void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn)
{
clear_bit(VHOST_WORK_QUEUED, &work->flags);
work->fn = fn;
}
EXPORT_SYMBOL_GPL(vhost_work_init);
/* Init poll structure */
void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
__poll_t mask, struct vhost_dev *dev,
struct vhost_virtqueue *vq)
{
init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);
init_poll_funcptr(&poll->table, vhost_poll_func);
poll->mask = mask;
poll->dev = dev;
poll->wqh = NULL;
poll->vq = vq;
vhost_work_init(&poll->work, fn);
}
EXPORT_SYMBOL_GPL(vhost_poll_init);
/* Start polling a file. We add ourselves to file's wait queue. The caller must
* keep a reference to a file until after vhost_poll_stop is called. */
int vhost_poll_start(struct vhost_poll *poll, struct file *file)
{
__poll_t mask;
if (poll->wqh)
return 0;
mask = vfs_poll(file, &poll->table);
if (mask)
vhost_poll_wakeup(&poll->wait, 0, 0, poll_to_key(mask));
if (mask & EPOLLERR) {
vhost_poll_stop(poll);
return -EINVAL;
}
return 0;
}
EXPORT_SYMBOL_GPL(vhost_poll_start);
/* Stop polling a file. After this function returns, it becomes safe to drop the
* file reference. You must also flush afterwards. */
void vhost_poll_stop(struct vhost_poll *poll)
{
if (poll->wqh) {
remove_wait_queue(poll->wqh, &poll->wait);
poll->wqh = NULL;
}
}
EXPORT_SYMBOL_GPL(vhost_poll_stop);
static void vhost_worker_queue(struct vhost_worker *worker,
struct vhost_work *work)
{
if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) {
/* We can only add the work to the list after we're
* sure it was not in the list.
* test_and_set_bit() implies a memory barrier.
*/
llist_add(&work->node, &worker->work_list);
worker->ops->wakeup(worker);
}
}
bool vhost_vq_work_queue(struct vhost_virtqueue *vq, struct vhost_work *work)
{
struct vhost_worker *worker;
bool queued = false;
rcu_read_lock();
worker = rcu_dereference(vq->worker);
if (worker) {
queued = true;
vhost_worker_queue(worker, work);
}
rcu_read_unlock();
return queued;
}
EXPORT_SYMBOL_GPL(vhost_vq_work_queue);
/**
* __vhost_worker_flush - flush a worker
* @worker: worker to flush
*
* The worker's flush_mutex must be held.
*/
static void __vhost_worker_flush(struct vhost_worker *worker)
{
struct vhost_flush_struct flush;
if (!worker->attachment_cnt || worker->killed)
return;
init_completion(&flush.wait_event);
vhost_work_init(&flush.work, vhost_flush_work);
vhost_worker_queue(worker, &flush.work);
/*
* Drop mutex in case our worker is killed and it needs to take the
* mutex to force cleanup.
*/
mutex_unlock(&worker->mutex);
wait_for_completion(&flush.wait_event);
mutex_lock(&worker->mutex);
}
static void vhost_worker_flush(struct vhost_worker *worker)
{
mutex_lock(&worker->mutex);
__vhost_worker_flush(worker);
mutex_unlock(&worker->mutex);
}
void vhost_dev_flush(struct vhost_dev *dev)
{
struct vhost_worker *worker;
unsigned long i;
xa_for_each(&dev->worker_xa, i, worker)
vhost_worker_flush(worker);
}
EXPORT_SYMBOL_GPL(vhost_dev_flush);
/* A lockless hint for busy polling code to exit the loop */
bool vhost_vq_has_work(struct vhost_virtqueue *vq)
{
struct vhost_worker *worker;
bool has_work = false;
rcu_read_lock();
worker = rcu_dereference(vq->worker);
if (worker && !llist_empty(&worker->work_list))
has_work = true;
rcu_read_unlock();
return has_work;
}
EXPORT_SYMBOL_GPL(vhost_vq_has_work);
void vhost_poll_queue(struct vhost_poll *poll)
{
vhost_vq_work_queue(poll->vq, &poll->work);
}
EXPORT_SYMBOL_GPL(vhost_poll_queue);
static void __vhost_vq_meta_reset(struct vhost_virtqueue *vq)
{
int j;
for (j = 0; j < VHOST_NUM_ADDRS; j++)
vq->meta_iotlb[j] = NULL;
}
static void vhost_vq_meta_reset(struct vhost_dev *d)
{
int i;
for (i = 0; i < d->nvqs; ++i)
__vhost_vq_meta_reset(d->vqs[i]);
}
static void vhost_vring_call_reset(struct vhost_vring_call *call_ctx)
{
call_ctx->ctx = NULL;
memset(&call_ctx->producer, 0x0, sizeof(struct irq_bypass_producer));
}
bool vhost_vq_is_setup(struct vhost_virtqueue *vq)
{
return vq->avail && vq->desc && vq->used && vhost_vq_access_ok(vq);
}
EXPORT_SYMBOL_GPL(vhost_vq_is_setup);
static void vhost_vq_reset(struct vhost_dev *dev,
struct vhost_virtqueue *vq)
{
vq->num = 1;
vq->desc = NULL;
vq->avail = NULL;
vq->used = NULL;
vq->last_avail_idx = 0;
vq->next_avail_head = 0;
vq->avail_idx = 0;
vq->last_used_idx = 0;
vq->signalled_used = 0;
vq->signalled_used_valid = false;
vq->used_flags = 0;
vq->log_used = false;
vq->log_addr = -1ull;
vq->private_data = NULL;
virtio_features_zero(vq->acked_features_array);
vq->acked_backend_features = 0;
vq->log_base = NULL;
vq->error_ctx = NULL;
vq->kick = NULL;
vq->log_ctx = NULL;
vhost_disable_cross_endian(vq);
vhost_reset_is_le(vq);
vq->busyloop_timeout = 0;
vq->umem = NULL;
vq->iotlb = NULL;
rcu_assign_pointer(vq->worker, NULL);
vhost_vring_call_reset(&vq->call_ctx);
__vhost_vq_meta_reset(vq);
}
static int vhost_run_work_kthread_list(void *data)
{
struct vhost_worker *worker = data;
struct vhost_work *work, *work_next;
struct vhost_dev *dev = worker->dev;
struct llist_node *node;
kthread_use_mm(dev->mm);
for (;;) {
/* mb paired w/ kthread_stop */
set_current_state(TASK_INTERRUPTIBLE);
if (kthread_should_stop()) {
__set_current_state(TASK_RUNNING);
break;
}
node = llist_del_all(&worker->work_list);
if (!node)
schedule();
node = llist_reverse_order(node);
/* make sure flag is seen after deletion */
smp_wmb();
llist_for_each_entry_safe(work, work_next, node, node) {
clear_bit(VHOST_WORK_QUEUED, &work->flags);
__set_current_state(TASK_RUNNING);
kcov_remote_start_common(worker->kcov_handle);
work->fn(work);
kcov_remote_stop();
cond_resched();
}
}
kthread_unuse_mm(dev->mm);
return 0;
}
static bool vhost_run_work_list(void *data)
{
struct vhost_worker *worker = data;
struct vhost_work *work, *work_next;
struct llist_node *node;
node = llist_del_all(&worker->work_list);
if (node) {
__set_current_state(TASK_RUNNING);
node = llist_reverse_order(node);
/* make sure flag is seen after deletion */
smp_wmb();
llist_for_each_entry_safe(work, work_next, node, node) {
clear_bit(VHOST_WORK_QUEUED, &work->flags);
kcov_remote_start_common(worker->kcov_handle);
work->fn(work);
kcov_remote_stop();
cond_resched();
}
}
return !!node;
}
static void vhost_worker_killed(void *data)
{
struct vhost_worker *worker = data;
struct vhost_dev *dev = worker->dev;
struct vhost_virtqueue *vq;
int i, attach_cnt = 0;
mutex_lock(&worker->mutex);
worker->killed = true;
for (i = 0; i < dev->nvqs; i++) {
vq = dev->vqs[i];
mutex_lock(&vq->mutex);
if (worker ==
rcu_dereference_check(vq->worker,
lockdep_is_held(&vq->mutex))) {
rcu_assign_pointer(vq->worker, NULL);
attach_cnt++;
}
mutex_unlock(&vq->mutex);
}
worker->attachment_cnt -= attach_cnt;
if (attach_cnt)
synchronize_rcu();
/*
* Finish vhost_worker_flush calls and any other works that snuck in
* before the synchronize_rcu.
*/
vhost_run_work_list(worker);
mutex_unlock(&worker->mutex);
}
static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq)
{
kfree(vq->indirect);
vq->indirect = NULL;
kfree(vq->log);
vq->log = NULL;
kfree(vq->heads);
vq->heads = NULL;
kfree(vq->nheads);
vq->nheads = NULL;
}
/* Helper to allocate iovec buffers for all vqs. */
static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
{
struct vhost_virtqueue *vq;
int i;
for (i = 0; i < dev->nvqs; ++i) {
vq = dev->vqs[i];
vq->indirect = kmalloc_array(UIO_MAXIOV,
sizeof(*vq->indirect),
GFP_KERNEL);
vq->log = kmalloc_array(dev->iov_limit, sizeof(*vq->log),
GFP_KERNEL);
vq->heads = kmalloc_array(dev->iov_limit, sizeof(*vq->heads),
GFP_KERNEL);
vq->nheads = kmalloc_array(dev->iov_limit, sizeof(*vq->nheads),
GFP_KERNEL);
if (!vq->indirect || !vq->log || !vq->heads || !vq->nheads)
goto err_nomem;
}
return 0;
err_nomem:
for (; i >= 0; --i)
vhost_vq_free_iovecs(dev->vqs[i]);
return -ENOMEM;
}
static void vhost_dev_free_iovecs(struct vhost_dev *dev)
{
int i;
for (i = 0; i < dev->nvqs; ++i)
vhost_vq_free_iovecs(dev->vqs[i]);
}
bool vhost_exceeds_weight(struct vhost_virtqueue *vq,
int pkts, int total_len)
{
struct vhost_dev *dev = vq->dev;
if ((dev->byte_weight && total_len >= dev->byte_weight) ||
pkts >= dev->weight) {
vhost_poll_queue(&vq->poll);
return true;
}
return false;
}
EXPORT_SYMBOL_GPL(vhost_exceeds_weight);
static size_t vhost_get_avail_size(struct vhost_virtqueue *vq,
unsigned int num)
{
size_t event __maybe_unused =
vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
return size_add(struct_size(vq->avail, ring, num), event);
}
static size_t vhost_get_used_size(struct vhost_virtqueue *vq,
unsigned int num)
{
size_t event __maybe_unused =
vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
return size_add(struct_size(vq->used, ring, num), event);
}
static size_t vhost_get_desc_size(struct vhost_virtqueue *vq,
unsigned int num)
{
return sizeof(*vq->desc) * num;
}
void vhost_dev_init(struct vhost_dev *dev,
struct vhost_virtqueue **vqs, int nvqs,
int iov_limit, int weight, int byte_weight,
bool use_worker,
int (*msg_handler)(struct vhost_dev *dev, u32 asid,
struct vhost_iotlb_msg *msg))
{
struct vhost_virtqueue *vq;
int i;
dev->vqs = vqs;
dev->nvqs = nvqs;
mutex_init(&dev->mutex);
dev->log_ctx = NULL;
dev->umem = NULL;
dev->iotlb = NULL;
dev->mm = NULL;
dev->iov_limit = iov_limit;
dev->weight = weight;
dev->byte_weight = byte_weight;
dev->use_worker = use_worker;
dev->msg_handler = msg_handler;
dev->fork_owner = fork_from_owner_default;
init_waitqueue_head(&dev->wait);
INIT_LIST_HEAD(&dev->read_list);
INIT_LIST_HEAD(&dev->pending_list);
spin_lock_init(&dev->iotlb_lock);
xa_init_flags(&dev->worker_xa, XA_FLAGS_ALLOC);
for (i = 0; i < dev->nvqs; ++i) {
vq = dev->vqs[i];
vq->log = NULL;
vq->indirect = NULL;
vq->heads = NULL;
vq->nheads = NULL;
vq->dev = dev;
mutex_init(&vq->mutex);
vhost_vq_reset(dev, vq);
if (vq->handle_kick)
vhost_poll_init(&vq->poll, vq->handle_kick,
EPOLLIN, dev, vq);
}
}
EXPORT_SYMBOL_GPL(vhost_dev_init);
/* Caller should have device mutex */
long vhost_dev_check_owner(struct vhost_dev *dev)
{
/* Are you the owner? If not, I don't think you mean to do that */
return dev->mm == current->mm ? 0 : -EPERM;
}
EXPORT_SYMBOL_GPL(vhost_dev_check_owner);
struct vhost_attach_cgroups_struct {
struct vhost_work work;
struct task_struct *owner;
int ret;
};
static void vhost_attach_cgroups_work(struct vhost_work *work)
{
struct vhost_attach_cgroups_struct *s;
s = container_of(work, struct vhost_attach_cgroups_struct, work);
s->ret = cgroup_attach_task_all(s->owner, current);
}
static int vhost_attach_task_to_cgroups(struct vhost_worker *worker)
{
struct vhost_attach_cgroups_struct attach;
int saved_cnt;
attach.owner = current;
vhost_work_init(&attach.work, vhost_attach_cgroups_work);
vhost_worker_queue(worker, &attach.work);
mutex_lock(&worker->mutex);
/*
* Bypass attachment_cnt check in __vhost_worker_flush:
* Temporarily change it to INT_MAX to bypass the check
*/
saved_cnt = worker->attachment_cnt;
worker->attachment_cnt = INT_MAX;
__vhost_worker_flush(worker);
worker->attachment_cnt = saved_cnt;
mutex_unlock(&worker->mutex);
return attach.ret;
}
/* Caller should have device mutex */
bool vhost_dev_has_owner(struct vhost_dev *dev)
{
return dev->mm;
}
EXPORT_SYMBOL_GPL(vhost_dev_has_owner);
static void vhost_attach_mm(struct vhost_dev *dev)
{
/* No owner, become one */
if (dev->use_worker) {
dev->mm = get_task_mm(current);
} else {
/* vDPA device does not use worker thread, so there's
* no need to hold the address space for mm. This helps
* to avoid deadlock in the case of mmap() which may
* hold the refcnt of the file and depends on release
* method to remove vma.
*/
dev->mm = current->mm;
mmgrab(dev->mm);
}
}
static void vhost_detach_mm(struct vhost_dev *dev)
{
if (!dev->mm)
return;
if (dev->use_worker)
mmput(dev->mm);
else
mmdrop(dev->mm);
dev->mm = NULL;
}
static void vhost_worker_destroy(struct vhost_dev *dev,
struct vhost_worker *worker)
{
if (!worker)
return;
WARN_ON(!llist_empty(&worker->work_list));
xa_erase(&dev->worker_xa, worker->id);
worker->ops->stop(worker);
kfree(worker);
}
static void vhost_workers_free(struct vhost_dev *dev)
{
struct vhost_worker *worker;
unsigned long i;
if (!dev->use_worker)
return;
for (i = 0; i < dev->nvqs; i++)
rcu_assign_pointer(dev->vqs[i]->worker, NULL);
/*
* Free the default worker we created and cleanup workers userspace
* created but couldn't clean up (it forgot or crashed).
*/
xa_for_each(&dev->worker_xa, i, worker)
vhost_worker_destroy(dev, worker);
xa_destroy(&dev->worker_xa);
}
static void vhost_task_wakeup(struct vhost_worker *worker)
{
return vhost_task_wake(worker->vtsk);
}
static void vhost_kthread_wakeup(struct vhost_worker *worker)
{
wake_up_process(worker->kthread_task);
}
static void vhost_task_do_stop(struct vhost_worker *worker)
{
return vhost_task_stop(worker->vtsk);
}
static void vhost_kthread_do_stop(struct vhost_worker *worker)
{
kthread_stop(worker->kthread_task);
}
static int vhost_task_worker_create(struct vhost_worker *worker,
struct vhost_dev *dev, const char *name)
{
struct vhost_task *vtsk;
u32 id;
int ret;
vtsk = vhost_task_create(vhost_run_work_list, vhost_worker_killed,
worker, name);
if (IS_ERR(vtsk))
return PTR_ERR(vtsk);
worker->vtsk = vtsk;
vhost_task_start(vtsk);
ret = xa_alloc(&dev->worker_xa, &id, worker, xa_limit_32b, GFP_KERNEL);
if (ret < 0) {
vhost_task_do_stop(worker);
return ret;
}
worker->id = id;
return 0;
}
static int vhost_kthread_worker_create(struct vhost_worker *worker,
struct vhost_dev *dev, const char *name)
{
struct task_struct *task;
u32 id;
int ret;
task = kthread_create(vhost_run_work_kthread_list, worker, "%s", name);
if (IS_ERR(task))
return PTR_ERR(task);
worker->kthread_task = task;
wake_up_process(task);
ret = xa_alloc(&dev->worker_xa, &id, worker, xa_limit_32b, GFP_KERNEL);
if (ret < 0)
goto stop_worker;
ret = vhost_attach_task_to_cgroups(worker);
if (ret)
goto stop_worker;
worker->id = id;
return 0;
stop_worker:
vhost_kthread_do_stop(worker);
return ret;
}
static const struct vhost_worker_ops kthread_ops = {
.create = vhost_kthread_worker_create,
.stop = vhost_kthread_do_stop,
.wakeup = vhost_kthread_wakeup,
};
static const struct vhost_worker_ops vhost_task_ops = {
.create = vhost_task_worker_create,
.stop = vhost_task_do_stop,
.wakeup = vhost_task_wakeup,
};
static struct vhost_worker *vhost_worker_create(struct vhost_dev *dev)
{
struct vhost_worker *worker;
char name[TASK_COMM_LEN];
int ret;
const struct vhost_worker_ops *ops = dev->fork_owner ? &vhost_task_ops :
&kthread_ops;
worker = kzalloc(sizeof(*worker), GFP_KERNEL_ACCOUNT);
if (!worker)
return NULL;
worker->dev = dev;
worker->ops = ops;
snprintf(name, sizeof(name), "vhost-%d", current->pid);
mutex_init(&worker->mutex);
init_llist_head(&worker->work_list);
worker->kcov_handle = kcov_common_handle();
ret = ops->create(worker, dev, name);
if (ret < 0)
goto free_worker;
return worker;
free_worker:
kfree(worker);
return NULL;
}
/* Caller must have device mutex */
static void __vhost_vq_attach_worker(struct vhost_virtqueue *vq,
struct vhost_worker *worker)
{
struct vhost_worker *old_worker;
mutex_lock(&worker->mutex);
if (worker->killed) {
mutex_unlock(&worker->mutex);
return;
}
mutex_lock(&vq->mutex);
old_worker = rcu_dereference_check(vq->worker,
lockdep_is_held(&vq->mutex));
rcu_assign_pointer(vq->worker, worker);
worker->attachment_cnt++;
if (!old_worker) {
mutex_unlock(&vq->mutex);
mutex_unlock(&worker->mutex);
return;
}
mutex_unlock(&vq->mutex);
mutex_unlock(&worker->mutex);
/*
* Take the worker mutex to make sure we see the work queued from
* device wide flushes which doesn't use RCU for execution.
*/
mutex_lock(&old_worker->mutex);
if (old_worker->killed) {
mutex_unlock(&old_worker->mutex);
return;
}
/*
* We don't want to call synchronize_rcu for every vq during setup
* because it will slow down VM startup. If we haven't done
* VHOST_SET_VRING_KICK and not done the driver specific
* SET_ENDPOINT/RUNNING then we can skip the sync since there will
* not be any works queued for scsi and net.
*/
mutex_lock(&vq->mutex);
if (!vhost_vq_get_backend(vq) && !vq->kick) {
mutex_unlock(&vq->mutex);
old_worker->attachment_cnt--;
mutex_unlock(&old_worker->mutex);
/*
* vsock can queue anytime after VHOST_VSOCK_SET_GUEST_CID.
* Warn if it adds support for multiple workers but forgets to
* handle the early queueing case.
*/
WARN_ON(!old_worker->attachment_cnt &&
!llist_empty(&old_worker->work_list));
return;
}
mutex_unlock(&vq->mutex);
/* Make sure new vq queue/flush/poll calls see the new worker */
synchronize_rcu();
/* Make sure whatever was queued gets run */
__vhost_worker_flush(old_worker);
old_worker->attachment_cnt--;
mutex_unlock(&old_worker->mutex);
}
/* Caller must have device mutex */
static int vhost_vq_attach_worker(struct vhost_virtqueue *vq,
struct vhost_vring_worker *info)
{
unsigned long index = info->worker_id;
struct vhost_dev *dev = vq->dev;
struct vhost_worker *worker;
if (!dev->use_worker)
return -EINVAL;
worker = xa_find(&dev->worker_xa, &index, UINT_MAX, XA_PRESENT);
if (!worker || worker->id != info->worker_id)
return -ENODEV;
__vhost_vq_attach_worker(vq, worker);
return 0;
}
/* Caller must have device mutex */
static int vhost_new_worker(struct vhost_dev *dev,
struct vhost_worker_state *info)
{
struct vhost_worker *worker;
worker = vhost_worker_create(dev);
if (!worker)
return -ENOMEM;
info->worker_id = worker->id;
return 0;
}
/* Caller must have device mutex */
static int vhost_free_worker(struct vhost_dev *dev,
struct vhost_worker_state *info)
{
unsigned long index = info->worker_id;
struct vhost_worker *worker;
worker = xa_find(&dev->worker_xa, &index, UINT_MAX, XA_PRESENT);
if (!worker || worker->id != info->worker_id)
return -ENODEV;
mutex_lock(&worker->mutex);
if (worker->attachment_cnt || worker->killed) {
mutex_unlock(&worker->mutex);
return -EBUSY;
}
/*
* A flush might have raced and snuck in before attachment_cnt was set
* to zero. Make sure flushes are flushed from the queue before
* freeing.
*/
__vhost_worker_flush(worker);
mutex_unlock(&worker->mutex);
vhost_worker_destroy(dev, worker);
return 0;
}
static int vhost_get_vq_from_user(struct vhost_dev *dev, void __user *argp,
struct vhost_virtqueue **vq, u32 *id)
{
u32 __user *idxp = argp;
u32 idx;
long r;
r = get_user(idx, idxp);
if (r < 0)
return r;
if (idx >= dev->nvqs)
return -ENOBUFS;
idx = array_index_nospec(idx, dev->nvqs);
*vq = dev->vqs[idx];
*id = idx;
return 0;
}
/* Caller must have device mutex */
long vhost_worker_ioctl(struct vhost_dev *dev, unsigned int ioctl,
void __user *argp)
{
struct vhost_vring_worker ring_worker;
struct vhost_worker_state state;
struct vhost_worker *worker;
struct vhost_virtqueue *vq;
long ret;
u32 idx;
if (!dev->use_worker)
return -EINVAL;
if (!vhost_dev_has_owner(dev))
return -EINVAL;
ret = vhost_dev_check_owner(dev);
if (ret)
return ret;
switch (ioctl) {
/* dev worker ioctls */
case VHOST_NEW_WORKER:
/*
* vhost_tasks will account for worker threads under the parent's
* NPROC value but kthreads do not. To avoid userspace overflowing
* the system with worker threads fork_owner must be true.
*/
if (!dev->fork_owner)
return -EFAULT;
ret = vhost_new_worker(dev, &state);
if (!ret && copy_to_user(argp, &state, sizeof(state)))
ret = -EFAULT;
return ret;
case VHOST_FREE_WORKER:
if (copy_from_user(&state, argp, sizeof(state)))
return -EFAULT;
return vhost_free_worker(dev, &state);
/* vring worker ioctls */
case VHOST_ATTACH_VRING_WORKER:
case VHOST_GET_VRING_WORKER:
break;
default:
return -ENOIOCTLCMD;
}
ret = vhost_get_vq_from_user(dev, argp, &vq, &idx);
if (ret)
return ret;
switch (ioctl) {
case VHOST_ATTACH_VRING_WORKER:
if (copy_from_user(&ring_worker, argp, sizeof(ring_worker))) {
ret = -EFAULT;
break;
}
ret = vhost_vq_attach_worker(vq, &ring_worker);
break;
case VHOST_GET_VRING_WORKER:
worker = rcu_dereference_check(vq->worker,
lockdep_is_held(&dev->mutex));
if (!worker) {
ret = -EINVAL;
break;
}
ring_worker.index = idx;
ring_worker.worker_id = worker->id;
if (copy_to_user(argp, &ring_worker, sizeof(ring_worker)))
ret = -EFAULT;
break;
default:
ret = -ENOIOCTLCMD;
break;
}
return ret;
}
EXPORT_SYMBOL_GPL(vhost_worker_ioctl);
/* Caller should have device mutex */
long vhost_dev_set_owner(struct vhost_dev *dev)
{
struct vhost_worker *worker;
int err, i;
/* Is there an owner already? */
if (vhost_dev_has_owner(dev)) {
err = -EBUSY;
goto err_mm;
}
vhost_attach_mm(dev);
err = vhost_dev_alloc_iovecs(dev);
if (err)
goto err_iovecs;
if (dev->use_worker) {
/*
* This should be done last, because vsock can queue work
* before VHOST_SET_OWNER so it simplifies the failure path
* below since we don't have to worry about vsock queueing
* while we free the worker.
*/
worker = vhost_worker_create(dev);
if (!worker) {
err = -ENOMEM;
goto err_worker;
}
for (i = 0; i < dev->nvqs; i++)
__vhost_vq_attach_worker(dev->vqs[i], worker);
}
return 0;
err_worker:
vhost_dev_free_iovecs(dev);
err_iovecs:
vhost_detach_mm(dev);
err_mm:
return err;
}
EXPORT_SYMBOL_GPL(vhost_dev_set_owner);
static struct vhost_iotlb *iotlb_alloc(void)
{
return vhost_iotlb_alloc(max_iotlb_entries,
VHOST_IOTLB_FLAG_RETIRE);
}
struct vhost_iotlb *vhost_dev_reset_owner_prepare(void)
{
return iotlb_alloc();
}
EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare);
/* Caller should have device mutex */
void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *umem)
{
int i;
vhost_dev_cleanup(dev);
dev->fork_owner = fork_from_owner_default;
dev->umem = umem;
/* We don't need VQ locks below since vhost_dev_cleanup makes sure
* VQs aren't running.
*/
for (i = 0; i < dev->nvqs; ++i)
dev->vqs[i]->umem = umem;
}
EXPORT_SYMBOL_GPL(vhost_dev_reset_owner);
void vhost_dev_stop(struct vhost_dev *dev)
{
int i;
for (i = 0; i < dev->nvqs; ++i) {
if (dev->vqs[i]->kick && dev->vqs[i]->handle_kick)
vhost_poll_stop(&dev->vqs[i]->poll);
}
vhost_dev_flush(dev);
}
EXPORT_SYMBOL_GPL(vhost_dev_stop);
void vhost_clear_msg(struct vhost_dev *dev)
{
struct vhost_msg_node *node, *n;
spin_lock(&dev->iotlb_lock);
list_for_each_entry_safe(node, n, &dev->read_list, node) {
list_del(&node->node);
kfree(node);
}
list_for_each_entry_safe(node, n, &dev->pending_list, node) {
list_del(&node->node);
kfree(node);
}
spin_unlock(&dev->iotlb_lock);
}
EXPORT_SYMBOL_GPL(vhost_clear_msg);
void vhost_dev_cleanup(struct vhost_dev *dev)
{
int i;
for (i = 0; i < dev->nvqs; ++i) {
if (dev->vqs[i]->error_ctx)
eventfd_ctx_put(dev->vqs[i]->error_ctx);
if (dev->vqs[i]->kick)
fput(dev->vqs[i]->kick);
if (dev->vqs[i]->call_ctx.ctx)
eventfd_ctx_put(dev->vqs[i]->call_ctx.ctx);
vhost_vq_reset(dev, dev->vqs[i]);
}
vhost_dev_free_iovecs(dev);
if (dev->log_ctx)
eventfd_ctx_put(dev->log_ctx);
dev->log_ctx = NULL;
/* No one will access memory at this point */
vhost_iotlb_free(dev->umem);
dev->umem = NULL;
vhost_iotlb_free(dev->iotlb);
dev->iotlb = NULL;
vhost_clear_msg(dev);
wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
vhost_workers_free(dev);
vhost_detach_mm(dev);
}
EXPORT_SYMBOL_GPL(vhost_dev_cleanup);
static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
{
u64 a = addr / VHOST_PAGE_SIZE / 8;
/* Make sure 64 bit math will not overflow. */
if (a > ULONG_MAX - (unsigned long)log_base ||
a + (unsigned long)log_base > ULONG_MAX)
return false;
return access_ok(log_base + a,
(sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
}
/* Make sure 64 bit math will not overflow. */
static bool vhost_overflow(u64 uaddr, u64 size)
{
if (uaddr > ULONG_MAX || size > ULONG_MAX)
return true;
if (!size)
return false;
return uaddr > ULONG_MAX - size + 1;
}
/* Caller should have vq mutex and device mutex. */
static bool vq_memory_access_ok(void __user *log_base, struct vhost_iotlb *umem,
int log_all)
{
struct vhost_iotlb_map *map;
if (!umem)
return false;
list_for_each_entry(map, &umem->list, link) {
unsigned long a = map->addr;
if (vhost_overflow(map->addr, map->size))
return false;
if (!access_ok((void __user *)a, map->size))
return false;
else if (log_all && !log_access_ok(log_base,
map->start,
map->size))
return false;
}
return true;
}
static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq,
u64 addr, unsigned int size,
int type)
{
const struct vhost_iotlb_map *map = vq->meta_iotlb[type];
if (!map)
return NULL;
return (void __user *)(uintptr_t)(map->addr + addr - map->start);
}
/* Can we switch to this memory table? */
/* Caller should have device mutex but not vq mutex */
static bool memory_access_ok(struct vhost_dev *d, struct vhost_iotlb *umem,
int log_all)
{
int i;
for (i = 0; i < d->nvqs; ++i) {
bool ok;
bool log;
mutex_lock(&d->vqs[i]->mutex);
log = log_all || vhost_has_feature(d->vqs[i], VHOST_F_LOG_ALL);
/* If ring is inactive, will check when it's enabled. */
if (d->vqs[i]->private_data)
ok = vq_memory_access_ok(d->vqs[i]->log_base,
umem, log);
else
ok = true;
mutex_unlock(&d->vqs[i]->mutex);
if (!ok)
return false;
}
return true;
}
static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
struct iovec iov[], int iov_size, int access);
static int vhost_copy_to_user(struct vhost_virtqueue *vq, void __user *to,
const void *from, unsigned size)
{
int ret;
if (!vq->iotlb)
return __copy_to_user(to, from, size);
else {
/* This function should be called after iotlb
* prefetch, which means we're sure that all vq
* could be access through iotlb. So -EAGAIN should
* not happen in this case.
*/
struct iov_iter t;
void __user *uaddr = vhost_vq_meta_fetch(vq,
(u64)(uintptr_t)to, size,
VHOST_ADDR_USED);
if (uaddr)
return __copy_to_user(uaddr, from, size);
ret = translate_desc(vq, (u64)(uintptr_t)to, size, vq->iotlb_iov,
ARRAY_SIZE(vq->iotlb_iov),
VHOST_ACCESS_WO);
if (ret < 0)
goto out;
iov_iter_init(&t, ITER_DEST, vq->iotlb_iov, ret, size);
ret = copy_to_iter(from, size, &t);
if (ret == size)
ret = 0;
}
out:
return ret;
}
static int vhost_copy_from_user(struct vhost_virtqueue *vq, void *to,
void __user *from, unsigned size)
{
int ret;
if (!vq->iotlb)
return __copy_from_user(to, from, size);
else {
/* This function should be called after iotlb
* prefetch, which means we're sure that vq
* could be access through iotlb. So -EAGAIN should
* not happen in this case.
*/
void __user *uaddr = vhost_vq_meta_fetch(vq,
(u64)(uintptr_t)from, size,
VHOST_ADDR_DESC);
struct iov_iter f;
if (uaddr)
return __copy_from_user(to, uaddr, size);
ret = translate_desc(vq, (u64)(uintptr_t)from, size, vq->iotlb_iov,
ARRAY_SIZE(vq->iotlb_iov),
VHOST_ACCESS_RO);
if (ret < 0) {
vq_err(vq, "IOTLB translation failure: uaddr "
"%p size 0x%llx\n", from,
(unsigned long long) size);
goto out;
}
iov_iter_init(&f, ITER_SOURCE, vq->iotlb_iov, ret, size);
ret = copy_from_iter(to, size, &f);
if (ret == size)
ret = 0;
}
out:
return ret;
}
static void __user *__vhost_get_user_slow(struct vhost_virtqueue *vq,
void __user *addr, unsigned int size,
int type)
{
int ret;
ret = translate_desc(vq, (u64)(uintptr_t)addr, size, vq->iotlb_iov,
ARRAY_SIZE(vq->iotlb_iov),
VHOST_ACCESS_RO);
if (ret < 0) {
vq_err(vq, "IOTLB translation failure: uaddr "
"%p size 0x%llx\n", addr,
(unsigned long long) size);
return NULL;
}
if (ret != 1 || vq->iotlb_iov[0].iov_len != size) {
vq_err(vq, "Non atomic userspace memory access: uaddr "
"%p size 0x%llx\n", addr,
(unsigned long long) size);
return NULL;
}
return vq->iotlb_iov[0].iov_base;
}
/* This function should be called after iotlb
* prefetch, which means we're sure that vq
* could be access through iotlb. So -EAGAIN should
* not happen in this case.
*/
static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq,
void __user *addr, unsigned int size,
int type)
{
void __user *uaddr = vhost_vq_meta_fetch(vq,
(u64)(uintptr_t)addr, size, type);
if (uaddr)
return uaddr;
return __vhost_get_user_slow(vq, addr, size, type);
}
#define vhost_put_user(vq, x, ptr) \
({ \
int ret; \
if (!vq->iotlb) { \
ret = __put_user(x, ptr); \
} else { \
__typeof__(ptr) to = \
(__typeof__(ptr)) __vhost_get_user(vq, ptr, \
sizeof(*ptr), VHOST_ADDR_USED); \
if (to != NULL) \
ret = __put_user(x, to); \
else \
ret = -EFAULT; \
} \
ret; \
})
static inline int vhost_put_avail_event(struct vhost_virtqueue *vq)
{
return vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx),
vhost_avail_event(vq));
}
static inline int vhost_put_used(struct vhost_virtqueue *vq,
struct vring_used_elem *head, int idx,
int count)
{
return vhost_copy_to_user(vq, vq->used->ring + idx, head,
count * sizeof(*head));
}
static inline int vhost_put_used_flags(struct vhost_virtqueue *vq)
{
return vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags),
&vq->used->flags);
}
static inline int vhost_put_used_idx(struct vhost_virtqueue *vq)
{
return vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx),
&vq->used->idx);
}
#define vhost_get_user(vq, x, ptr, type) \
({ \
int ret; \
if (!vq->iotlb) { \
ret = __get_user(x, ptr); \
} else { \
__typeof__(ptr) from = \
(__typeof__(ptr)) __vhost_get_user(vq, ptr, \
sizeof(*ptr), \
type); \
if (from != NULL) \
ret = __get_user(x, from); \
else \
ret = -EFAULT; \
} \
ret; \
})
#define vhost_get_avail(vq, x, ptr) \
vhost_get_user(vq, x, ptr, VHOST_ADDR_AVAIL)
#define vhost_get_used(vq, x, ptr) \
vhost_get_user(vq, x, ptr, VHOST_ADDR_USED)
static void vhost_dev_lock_vqs(struct vhost_dev *d)
{
int i = 0;
for (i = 0; i < d->nvqs; ++i)
mutex_lock_nested(&d->vqs[i]->mutex, i);
}
static void vhost_dev_unlock_vqs(struct vhost_dev *d)
{
int i = 0;
for (i = 0; i < d->nvqs; ++i)
mutex_unlock(&d->vqs[i]->mutex);
}
static inline int vhost_get_avail_idx(struct vhost_virtqueue *vq)
{
__virtio16 idx;
int r;
r = vhost_get_avail(vq, idx, &vq->avail->idx);
if (unlikely(r < 0)) {
vq_err(vq, "Failed to access available index at %p (%d)\n",
&vq->avail->idx, r);
return r;
}
/* Check it isn't doing very strange thing with available indexes */
vq->avail_idx = vhost16_to_cpu(vq, idx);
if (unlikely((u16)(vq->avail_idx - vq->last_avail_idx) > vq->num)) {
vq_err(vq, "Invalid available index change from %u to %u",
vq->last_avail_idx, vq->avail_idx);
return -EINVAL;
}
/* We're done if there is nothing new */
if (vq->avail_idx == vq->last_avail_idx)
return 0;
/*
* We updated vq->avail_idx so we need a memory barrier between
* the index read above and the caller reading avail ring entries.
*/
smp_rmb();
return 1;
}
static inline int vhost_get_avail_head(struct vhost_virtqueue *vq,
__virtio16 *head, int idx)
{
return vhost_get_avail(vq, *head,
&vq->avail->ring[idx & (vq->num - 1)]);
}
static inline int vhost_get_avail_flags(struct vhost_virtqueue *vq,
__virtio16 *flags)
{
return vhost_get_avail(vq, *flags, &vq->avail->flags);
}
static inline int vhost_get_used_event(struct vhost_virtqueue *vq,
__virtio16 *event)
{
return vhost_get_avail(vq, *event, vhost_used_event(vq));
}
static inline int vhost_get_used_idx(struct vhost_virtqueue *vq,
__virtio16 *idx)
{
return vhost_get_used(vq, *idx, &vq->used->idx);
}
static inline int vhost_get_desc(struct vhost_virtqueue *vq,
struct vring_desc *desc, int idx)
{
return vhost_copy_from_user(vq, desc, vq->desc + idx, sizeof(*desc));
}
static void vhost_iotlb_notify_vq(struct vhost_dev *d,
struct vhost_iotlb_msg *msg)
{
struct vhost_msg_node *node, *n;
spin_lock(&d->iotlb_lock);
list_for_each_entry_safe(node, n, &d->pending_list, node) {
struct vhost_iotlb_msg *vq_msg = &node->msg.iotlb;
if (msg->iova <= vq_msg->iova &&
msg->iova + msg->size - 1 >= vq_msg->iova &&
vq_msg->type == VHOST_IOTLB_MISS) {
vhost_poll_queue(&node->vq->poll);
list_del(&node->node);
kfree(node);
}
}
spin_unlock(&d->iotlb_lock);
}
static bool umem_access_ok(u64 uaddr, u64 size, int access)
{
unsigned long a = uaddr;
/* Make sure 64 bit math will not overflow. */
if (vhost_overflow(uaddr, size))
return false;
if ((access & VHOST_ACCESS_RO) &&
!access_ok((void __user *)a, size))
return false;
if ((access & VHOST_ACCESS_WO) &&
!access_ok((void __user *)a, size))
return false;
return true;
}
static int vhost_process_iotlb_msg(struct vhost_dev *dev, u32 asid,
struct vhost_iotlb_msg *msg)
{
int ret = 0;
if (asid != 0)
return -EINVAL;
mutex_lock(&dev->mutex);
vhost_dev_lock_vqs(dev);
switch (msg->type) {
case VHOST_IOTLB_UPDATE:
if (!dev->iotlb) {
ret = -EFAULT;
break;
}
if (!umem_access_ok(msg->uaddr, msg->size, msg->perm)) {
ret = -EFAULT;
break;
}
vhost_vq_meta_reset(dev);
if (vhost_iotlb_add_range(dev->iotlb, msg->iova,
msg->iova + msg->size - 1,
msg->uaddr, msg->perm)) {
ret = -ENOMEM;
break;
}
vhost_iotlb_notify_vq(dev, msg);
break;
case VHOST_IOTLB_INVALIDATE:
if (!dev->iotlb) {
ret = -EFAULT;
break;
}
vhost_vq_meta_reset(dev);
vhost_iotlb_del_range(dev->iotlb, msg->iova,
msg->iova + msg->size - 1);
break;
default:
ret = -EINVAL;
break;
}
vhost_dev_unlock_vqs(dev);
mutex_unlock(&dev->mutex);
return ret;
}
ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
struct iov_iter *from)
{
struct vhost_iotlb_msg msg;
size_t offset;
int type, ret;
u32 asid = 0;
ret = copy_from_iter(&type, sizeof(type), from);
if (ret != sizeof(type)) {
ret = -EINVAL;
goto done;
}
switch (type) {
case VHOST_IOTLB_MSG:
/* There maybe a hole after type for V1 message type,
* so skip it here.
*/
offset = offsetof(struct vhost_msg, iotlb) - sizeof(int);
break;
case VHOST_IOTLB_MSG_V2:
if (vhost_backend_has_feature(dev->vqs[0],
VHOST_BACKEND_F_IOTLB_ASID)) {
ret = copy_from_iter(&asid, sizeof(asid), from);
if (ret != sizeof(asid)) {
ret = -EINVAL;
goto done;
}
offset = 0;
} else
offset = sizeof(__u32);
break;
default:
ret = -EINVAL;
goto done;
}
iov_iter_advance(from, offset);
ret = copy_from_iter(&msg, sizeof(msg), from);
if (ret != sizeof(msg)) {
ret = -EINVAL;
goto done;
}
if (msg.type == VHOST_IOTLB_UPDATE && msg.size == 0) {
ret = -EINVAL;
goto done;
}
if (dev->msg_handler)
ret = dev->msg_handler(dev, asid, &msg);
else
ret = vhost_process_iotlb_msg(dev, asid, &msg);
if (ret) {
ret = -EFAULT;
goto done;
}
ret = (type == VHOST_IOTLB_MSG) ? sizeof(struct vhost_msg) :
sizeof(struct vhost_msg_v2);
done:
return ret;
}
EXPORT_SYMBOL(vhost_chr_write_iter);
__poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
poll_table *wait)
{
__poll_t mask = 0;
poll_wait(file, &dev->wait, wait);
if (!list_empty(&dev->read_list))
mask |= EPOLLIN | EPOLLRDNORM;
return mask;
}
EXPORT_SYMBOL(vhost_chr_poll);
ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
int noblock)
{
DEFINE_WAIT(wait);
struct vhost_msg_node *node;
ssize_t ret = 0;
unsigned size = sizeof(struct vhost_msg);
if (iov_iter_count(to) < size)
return 0;
while (1) {
if (!noblock)
prepare_to_wait(&dev->wait, &wait,
TASK_INTERRUPTIBLE);
node = vhost_dequeue_msg(dev, &dev->read_list);
if (node)
break;
if (noblock) {
ret = -EAGAIN;
break;
}
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
if (!dev->iotlb) {
ret = -EBADFD;
break;
}
schedule();
}
if (!noblock)
finish_wait(&dev->wait, &wait);
if (node) {
struct vhost_iotlb_msg *msg;
void *start = &node->msg;
switch (node->msg.type) {
case VHOST_IOTLB_MSG:
size = sizeof(node->msg);
msg = &node->msg.iotlb;
break;
case VHOST_IOTLB_MSG_V2:
size = sizeof(node->msg_v2);
msg = &node->msg_v2.iotlb;
break;
default:
BUG();
break;
}
ret = copy_to_iter(start, size, to);
if (ret != size || msg->type != VHOST_IOTLB_MISS) {
kfree(node);
return ret;
}
vhost_enqueue_msg(dev, &dev->pending_list, node);
}
return ret;
}
EXPORT_SYMBOL_GPL(vhost_chr_read_iter);
static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access)
{
struct vhost_dev *dev = vq->dev;
struct vhost_msg_node *node;
struct vhost_iotlb_msg *msg;
bool v2 = vhost_backend_has_feature(vq, VHOST_BACKEND_F_IOTLB_MSG_V2);
node = vhost_new_msg(vq, v2 ? VHOST_IOTLB_MSG_V2 : VHOST_IOTLB_MSG);
if (!node)
return -ENOMEM;
if (v2) {
node->msg_v2.type = VHOST_IOTLB_MSG_V2;
msg = &node->msg_v2.iotlb;
} else {
msg = &node->msg.iotlb;
}
msg->type = VHOST_IOTLB_MISS;
msg->iova = iova;
msg->perm = access;
vhost_enqueue_msg(dev, &dev->read_list, node);
return 0;
}
static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
vring_desc_t __user *desc,
vring_avail_t __user *avail,
vring_used_t __user *used)
{
/* If an IOTLB device is present, the vring addresses are
* GIOVAs. Access validation occurs at prefetch time. */
if (vq->iotlb)
return true;
return access_ok(desc, vhost_get_desc_size(vq, num)) &&
access_ok(avail, vhost_get_avail_size(vq, num)) &&
access_ok(used, vhost_get_used_size(vq, num));
}
static void vhost_vq_meta_update(struct vhost_virtqueue *vq,
const struct vhost_iotlb_map *map,
int type)
{
int access = (type == VHOST_ADDR_USED) ?
VHOST_ACCESS_WO : VHOST_ACCESS_RO;
if (likely(map->perm & access))
vq->meta_iotlb[type] = map;
}
static bool iotlb_access_ok(struct vhost_virtqueue *vq,
int access, u64 addr, u64 len, int type)
{
const struct vhost_iotlb_map *map;
struct vhost_iotlb *umem = vq->iotlb;
u64 s = 0, size, orig_addr = addr, last = addr + len - 1;
if (vhost_vq_meta_fetch(vq, addr, len, type))
return true;
while (len > s) {
map = vhost_iotlb_itree_first(umem, addr, last);
if (map == NULL || map->start > addr) {
vhost_iotlb_miss(vq, addr, access);
return false;
} else if (!(map->perm & access)) {
/* Report the possible access violation by
* request another translation from userspace.
*/
return false;
}
size = map->size - addr + map->start;
if (orig_addr == addr && size >= len)
vhost_vq_meta_update(vq, map, type);
s += size;
addr += size;
}
return true;
}
int vq_meta_prefetch(struct vhost_virtqueue *vq)
{
unsigned int num = vq->num;
if (!vq->iotlb)
return 1;
return iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->desc,
vhost_get_desc_size(vq, num), VHOST_ADDR_DESC) &&
iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->avail,
vhost_get_avail_size(vq, num),
VHOST_ADDR_AVAIL) &&
iotlb_access_ok(vq, VHOST_MAP_WO, (u64)(uintptr_t)vq->used,
vhost_get_used_size(vq, num), VHOST_ADDR_USED);
}
EXPORT_SYMBOL_GPL(vq_meta_prefetch);
/* Can we log writes? */
/* Caller should have device mutex but not vq mutex */
bool vhost_log_access_ok(struct vhost_dev *dev)
{
return memory_access_ok(dev, dev->umem, 1);
}
EXPORT_SYMBOL_GPL(vhost_log_access_ok);
static bool vq_log_used_access_ok(struct vhost_virtqueue *vq,
void __user *log_base,
bool log_used,
u64 log_addr)
{
/* If an IOTLB device is present, log_addr is a GIOVA that
* will never be logged by log_used(). */
if (vq->iotlb)
return true;
return !log_used || log_access_ok(log_base, log_addr,
vhost_get_used_size(vq, vq->num));
}
/* Verify access for write logging. */
/* Caller should have vq mutex and device mutex */
static bool vq_log_access_ok(struct vhost_virtqueue *vq,
void __user *log_base)
{
return vq_memory_access_ok(log_base, vq->umem,
vhost_has_feature(vq, VHOST_F_LOG_ALL)) &&
vq_log_used_access_ok(vq, log_base, vq->log_used, vq->log_addr);
}
/* Can we start vq? */
/* Caller should have vq mutex and device mutex */
bool vhost_vq_access_ok(struct vhost_virtqueue *vq)
{
if (!vq_log_access_ok(vq, vq->log_base))
return false;
return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);
}
EXPORT_SYMBOL_GPL(vhost_vq_access_ok);
static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
{
struct vhost_memory mem, *newmem;
struct vhost_memory_region *region;
struct vhost_iotlb *newumem, *oldumem;
unsigned long size = offsetof(struct vhost_memory, regions);
int i;
if (copy_from_user(&mem, m, size))
return -EFAULT;
if (mem.padding)
return -EOPNOTSUPP;
if (mem.nregions > max_mem_regions)
return -E2BIG;
newmem = kvzalloc(struct_size(newmem, regions, mem.nregions),
GFP_KERNEL);
if (!newmem)
return -ENOMEM;
memcpy(newmem, &mem, size);
if (copy_from_user(newmem->regions, m->regions,
flex_array_size(newmem, regions, mem.nregions))) {
kvfree(newmem);
return -EFAULT;
}
newumem = iotlb_alloc();
if (!newumem) {
kvfree(newmem);
return -ENOMEM;
}
for (region = newmem->regions;
region < newmem->regions + mem.nregions;
region++) {
if (vhost_iotlb_add_range(newumem,
region->guest_phys_addr,
region->guest_phys_addr +
region->memory_size - 1,
region->userspace_addr,
VHOST_MAP_RW))
goto err;
}
if (!memory_access_ok(d, newumem, 0))
goto err;
oldumem = d->umem;
d->umem = newumem;
/* All memory accesses are done under some VQ mutex. */
for (i = 0; i < d->nvqs; ++i) {
mutex_lock(&d->vqs[i]->mutex);
d->vqs[i]->umem = newumem;
mutex_unlock(&d->vqs[i]->mutex);
}
kvfree(newmem);
vhost_iotlb_free(oldumem);
return 0;
err:
vhost_iotlb_free(newumem);
kvfree(newmem);
return -EFAULT;
}
static long vhost_vring_set_num(struct vhost_dev *d,
struct vhost_virtqueue *vq,
void __user *argp)
{
struct vhost_vring_state s;
/* Resizing ring with an active backend?
* You don't want to do that. */
if (vq->private_data)
return -EBUSY;
if (copy_from_user(&s, argp, sizeof s))
return -EFAULT;
if (!s.num || s.num > 0xffff || (s.num & (s.num - 1)))
return -EINVAL;
vq->num = s.num;
return 0;
}
static long vhost_vring_set_addr(struct vhost_dev *d,
struct vhost_virtqueue *vq,
void __user *argp)
{
struct vhost_vring_addr a;
if (copy_from_user(&a, argp, sizeof a))
return -EFAULT;
if (a.flags & ~(0x1 << VHOST_VRING_F_LOG))
return -EOPNOTSUPP;
/* For 32bit, verify that the top 32bits of the user
data are set to zero. */
if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
(u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
(u64)(unsigned long)a.avail_user_addr != a.avail_user_addr)
return -EFAULT;
/* Make sure it's safe to cast pointers to vring types. */
BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
(a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
(a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1)))
return -EINVAL;
/* We only verify access here if backend is configured.
* If it is not, we don't as size might not have been setup.
* We will verify when backend is configured. */
if (vq->private_data) {
if (!vq_access_ok(vq, vq->num,
(void __user *)(unsigned long)a.desc_user_addr,
(void __user *)(unsigned long)a.avail_user_addr,
(void __user *)(unsigned long)a.used_user_addr))
return -EINVAL;
/* Also validate log access for used ring if enabled. */
if (!vq_log_used_access_ok(vq, vq->log_base,
a.flags & (0x1 << VHOST_VRING_F_LOG),
a.log_guest_addr))
return -EINVAL;
}
vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
vq->log_addr = a.log_guest_addr;
vq->used = (void __user *)(unsigned long)a.used_user_addr;
return 0;
}
static long vhost_vring_set_num_addr(struct vhost_dev *d,
struct vhost_virtqueue *vq,
unsigned int ioctl,
void __user *argp)
{
long r;
mutex_lock(&vq->mutex);
switch (ioctl) {
case VHOST_SET_VRING_NUM:
r = vhost_vring_set_num(d, vq, argp);
break;
case VHOST_SET_VRING_ADDR:
r = vhost_vring_set_addr(d, vq, argp);
break;
default:
BUG();
}
mutex_unlock(&vq->mutex);
return r;
}
long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
{
struct file *eventfp, *filep = NULL;
bool pollstart = false, pollstop = false;
struct eventfd_ctx *ctx = NULL;
struct vhost_virtqueue *vq;
struct vhost_vring_state s;
struct vhost_vring_file f;
u32 idx;
long r;
r = vhost_get_vq_from_user(d, argp, &vq, &idx);
if (r < 0)
return r;
if (ioctl == VHOST_SET_VRING_NUM ||
ioctl == VHOST_SET_VRING_ADDR) {
return vhost_vring_set_num_addr(d, vq, ioctl, argp);
}
mutex_lock(&vq->mutex);
switch (ioctl) {
case VHOST_SET_VRING_BASE:
/* Moving base with an active backend?
* You don't want to do that. */
if (vq->private_data) {
r = -EBUSY;
break;
}
if (copy_from_user(&s, argp, sizeof s)) {
r = -EFAULT;
break;
}
if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) {
vq->next_avail_head = vq->last_avail_idx =
s.num & 0xffff;
vq->last_used_idx = (s.num >> 16) & 0xffff;
} else {
if (s.num > 0xffff) {
r = -EINVAL;
break;
}
vq->next_avail_head = vq->last_avail_idx = s.num;
}
/* Forget the cached index value. */
vq->avail_idx = vq->last_avail_idx;
break;
case VHOST_GET_VRING_BASE:
s.index = idx;
if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
s.num = (u32)vq->last_avail_idx | ((u32)vq->last_used_idx << 16);
else
s.num = vq->last_avail_idx;
if (copy_to_user(argp, &s, sizeof s))
r = -EFAULT;
break;
case VHOST_SET_VRING_KICK:
if (copy_from_user(&f, argp, sizeof f)) {
r = -EFAULT;
break;
}
eventfp = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_fget(f.fd);
if (IS_ERR(eventfp)) {
r = PTR_ERR(eventfp);
break;
}
if (eventfp != vq->kick) {
pollstop = (filep = vq->kick) != NULL;
pollstart = (vq->kick = eventfp) != NULL;
} else
filep = eventfp;
break;
case VHOST_SET_VRING_CALL:
if (copy_from_user(&f, argp, sizeof f)) {
r = -EFAULT;
break;
}
ctx = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(f.fd);
if (IS_ERR(ctx)) {
r = PTR_ERR(ctx);
break;
}
swap(ctx, vq->call_ctx.ctx);
break;
case VHOST_SET_VRING_ERR:
if (copy_from_user(&f, argp, sizeof f)) {
r = -EFAULT;
break;
}
ctx = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(f.fd);
if (IS_ERR(ctx)) {
r = PTR_ERR(ctx);
break;
}
swap(ctx, vq->error_ctx);
break;
case VHOST_SET_VRING_ENDIAN:
r = vhost_set_vring_endian(vq, argp);
break;
case VHOST_GET_VRING_ENDIAN:
r = vhost_get_vring_endian(vq, idx, argp);
break;
case VHOST_SET_VRING_BUSYLOOP_TIMEOUT:
if (copy_from_user(&s, argp, sizeof(s))) {
r = -EFAULT;
break;
}
vq->busyloop_timeout = s.num;
break;
case VHOST_GET_VRING_BUSYLOOP_TIMEOUT:
s.index = idx;
s.num = vq->busyloop_timeout;
if (copy_to_user(argp, &s, sizeof(s)))
r = -EFAULT;
break;
default:
r = -ENOIOCTLCMD;
}
if (pollstop && vq->handle_kick)
vhost_poll_stop(&vq->poll);
if (!IS_ERR_OR_NULL(ctx))
eventfd_ctx_put(ctx);
if (filep)
fput(filep);
if (pollstart && vq->handle_kick)
r = vhost_poll_start(&vq->poll, vq->kick);
mutex_unlock(&vq->mutex);
if (pollstop && vq->handle_kick)
vhost_dev_flush(vq->poll.dev);
return r;
}
EXPORT_SYMBOL_GPL(vhost_vring_ioctl);
int vhost_init_device_iotlb(struct vhost_dev *d)
{
struct vhost_iotlb *niotlb, *oiotlb;
int i;
niotlb = iotlb_alloc();
if (!niotlb)
return -ENOMEM;
oiotlb = d->iotlb;
d->iotlb = niotlb;
for (i = 0; i < d->nvqs; ++i) {
struct vhost_virtqueue *vq = d->vqs[i];
mutex_lock(&vq->mutex);
vq->iotlb = niotlb;
__vhost_vq_meta_reset(vq);
mutex_unlock(&vq->mutex);
}
vhost_iotlb_free(oiotlb);
return 0;
}
EXPORT_SYMBOL_GPL(vhost_init_device_iotlb);
/* Caller must have device mutex */
long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
{
struct eventfd_ctx *ctx;
u64 p;
long r;
int i, fd;
/* If you are not the owner, you can become one */
if (ioctl == VHOST_SET_OWNER) {
r = vhost_dev_set_owner(d);
goto done;
}
#ifdef CONFIG_VHOST_ENABLE_FORK_OWNER_CONTROL
if (ioctl == VHOST_SET_FORK_FROM_OWNER) {
/* Only allow modification before owner is set */
if (vhost_dev_has_owner(d)) {
r = -EBUSY;
goto done;
}
u8 fork_owner_val;
if (get_user(fork_owner_val, (u8 __user *)argp)) {
r = -EFAULT;
goto done;
}
if (fork_owner_val != VHOST_FORK_OWNER_TASK &&
fork_owner_val != VHOST_FORK_OWNER_KTHREAD) {
r = -EINVAL;
goto done;
}
d->fork_owner = !!fork_owner_val;
r = 0;
goto done;
}
if (ioctl == VHOST_GET_FORK_FROM_OWNER) {
u8 fork_owner_val = d->fork_owner;
if (fork_owner_val != VHOST_FORK_OWNER_TASK &&
fork_owner_val != VHOST_FORK_OWNER_KTHREAD) {
r = -EINVAL;
goto done;
}
if (put_user(fork_owner_val, (u8 __user *)argp)) {
r = -EFAULT;
goto done;
}
r = 0;
goto done;
}
#endif
/* You must be the owner to do anything else */
r = vhost_dev_check_owner(d);
if (r)
goto done;
switch (ioctl) {
case VHOST_SET_MEM_TABLE:
r = vhost_set_memory(d, argp);
break;
case VHOST_SET_LOG_BASE:
if (copy_from_user(&p, argp, sizeof p)) {
r = -EFAULT;
break;
}
if ((u64)(unsigned long)p != p) {
r = -EFAULT;
break;
}
for (i = 0; i < d->nvqs; ++i) {
struct vhost_virtqueue *vq;
void __user *base = (void __user *)(unsigned long)p;
vq = d->vqs[i];
mutex_lock(&vq->mutex);
/* If ring is inactive, will check when it's enabled. */
if (vq->private_data && !vq_log_access_ok(vq, base))
r = -EFAULT;
else
vq->log_base = base;
mutex_unlock(&vq->mutex);
}
break;
case VHOST_SET_LOG_FD:
r = get_user(fd, (int __user *)argp);
if (r < 0)
break;
ctx = fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(fd);
if (IS_ERR(ctx)) {
r = PTR_ERR(ctx);
break;
}
swap(ctx, d->log_ctx);
for (i = 0; i < d->nvqs; ++i) {
mutex_lock(&d->vqs[i]->mutex);
d->vqs[i]->log_ctx = d->log_ctx;
mutex_unlock(&d->vqs[i]->mutex);
}
if (ctx)
eventfd_ctx_put(ctx);
break;
default:
r = -ENOIOCTLCMD;
break;
}
done:
return r;
}
EXPORT_SYMBOL_GPL(vhost_dev_ioctl);
/* TODO: This is really inefficient. We need something like get_user()
* (instruction directly accesses the data, with an exception table entry
* returning -EFAULT). See Documentation/arch/x86/exception-tables.rst.
*/
static int set_bit_to_user(int nr, void __user *addr)
{
unsigned long log = (unsigned long)addr;
struct page *page;
void *base;
int bit = nr + (log % PAGE_SIZE) * 8;
int r;
r = pin_user_pages_fast(log, 1, FOLL_WRITE, &page);
if (r < 0)
return r;
BUG_ON(r != 1);
base = kmap_atomic(page);
set_bit(bit, base);
kunmap_atomic(base);
unpin_user_pages_dirty_lock(&page, 1, true);
return 0;
}
static int log_write(void __user *log_base,
u64 write_address, u64 write_length)
{
u64 write_page = write_address / VHOST_PAGE_SIZE;
int r;
if (!write_length)
return 0;
write_length += write_address % VHOST_PAGE_SIZE;
for (;;) {
u64 base = (u64)(unsigned long)log_base;
u64 log = base + write_page / 8;
int bit = write_page % 8;
if ((u64)(unsigned long)log != log)
return -EFAULT;
r = set_bit_to_user(bit, (void __user *)(unsigned long)log);
if (r < 0)
return r;
if (write_length <= VHOST_PAGE_SIZE)
break;
write_length -= VHOST_PAGE_SIZE;
write_page += 1;
}
return r;
}
static int log_write_hva(struct vhost_virtqueue *vq, u64 hva, u64 len)
{
struct vhost_iotlb *umem = vq->umem;
struct vhost_iotlb_map *u;
u64 start, end, l, min;
int r;
bool hit = false;
while (len) {
min = len;
/* More than one GPAs can be mapped into a single HVA. So
* iterate all possible umems here to be safe.
*/
list_for_each_entry(u, &umem->list, link) {
if (u->addr > hva - 1 + len ||
u->addr - 1 + u->size < hva)
continue;
start = max(u->addr, hva);
end = min(u->addr - 1 + u->size, hva - 1 + len);
l = end - start + 1;
r = log_write(vq->log_base,
u->start + start - u->addr,
l);
if (r < 0)
return r;
hit = true;
min = min(l, min);
}
if (!hit)
return -EFAULT;
len -= min;
hva += min;
}
return 0;
}
static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len)
{
struct iovec *iov = vq->log_iov;
int i, ret;
if (!vq->iotlb)
return log_write(vq->log_base, vq->log_addr + used_offset, len);
ret = translate_desc(vq, (uintptr_t)vq->used + used_offset,
len, iov, 64, VHOST_ACCESS_WO);
if (ret < 0)
return ret;
for (i = 0; i < ret; i++) {
ret = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
iov[i].iov_len);
if (ret)
return ret;
}
return 0;
}
/*
* vhost_log_write() - Log in dirty page bitmap
* @vq: vhost virtqueue.
* @log: Array of dirty memory in GPA.
* @log_num: Size of vhost_log arrary.
* @len: The total length of memory buffer to log in the dirty bitmap.
* Some drivers may only partially use pages shared via the last
* vring descriptor (i.e. vhost-net RX buffer).
* Use (len == U64_MAX) to indicate the driver would log all
* pages of vring descriptors.
* @iov: Array of dirty memory in HVA.
* @count: Size of iovec array.
*/
int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
unsigned int log_num, u64 len, struct iovec *iov, int count)
{
int i, r;
/* Make sure data written is seen before log. */
smp_wmb();
if (vq->iotlb) {
for (i = 0; i < count; i++) {
r = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
iov[i].iov_len);
if (r < 0)
return r;
}
return 0;
}
for (i = 0; i < log_num; ++i) {
u64 l = min(log[i].len, len);
r = log_write(vq->log_base, log[i].addr, l);
if (r < 0)
return r;
if (len != U64_MAX)
len -= l;
}
if (vq->log_ctx)
eventfd_signal(vq->log_ctx);
return 0;
}
EXPORT_SYMBOL_GPL(vhost_log_write);
static int vhost_update_used_flags(struct vhost_virtqueue *vq)
{
void __user *used;
if (vhost_put_used_flags(vq))
return -EFAULT;
if (unlikely(vq->log_used)) {
/* Make sure the flag is seen before log. */
smp_wmb();
/* Log used flag write. */
used = &vq->used->flags;
log_used(vq, (used - (void __user *)vq->used),
sizeof vq->used->flags);
if (vq->log_ctx)
eventfd_signal(vq->log_ctx);
}
return 0;
}
static int vhost_update_avail_event(struct vhost_virtqueue *vq)
{
if (vhost_put_avail_event(vq))
return -EFAULT;
if (unlikely(vq->log_used)) {
void __user *used;
/* Make sure the event is seen before log. */
smp_wmb();
/* Log avail event write */
used = vhost_avail_event(vq);
log_used(vq, (used - (void __user *)vq->used),
sizeof *vhost_avail_event(vq));
if (vq->log_ctx)
eventfd_signal(vq->log_ctx);
}
return 0;
}
int vhost_vq_init_access(struct vhost_virtqueue *vq)
{
__virtio16 last_used_idx;
int r;
bool is_le = vq->is_le;
if (!vq->private_data)
return 0;
vhost_init_is_le(vq);
r = vhost_update_used_flags(vq);
if (r)
goto err;
vq->signalled_used_valid = false;
if (!vq->iotlb &&
!access_ok(&vq->used->idx, sizeof vq->used->idx)) {
r = -EFAULT;
goto err;
}
r = vhost_get_used_idx(vq, &last_used_idx);
if (r) {
vq_err(vq, "Can't access used idx at %p\n",
&vq->used->idx);
goto err;
}
vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx);
return 0;
err:
vq->is_le = is_le;
return r;
}
EXPORT_SYMBOL_GPL(vhost_vq_init_access);
static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
struct iovec iov[], int iov_size, int access)
{
const struct vhost_iotlb_map *map;
struct vhost_dev *dev = vq->dev;
struct vhost_iotlb *umem = dev->iotlb ? dev->iotlb : dev->umem;
struct iovec *_iov;
u64 s = 0, last = addr + len - 1;
int ret = 0;
while ((u64)len > s) {
u64 size;
if (unlikely(ret >= iov_size)) {
ret = -ENOBUFS;
break;
}
map = vhost_iotlb_itree_first(umem, addr, last);
if (map == NULL || map->start > addr) {
if (umem != dev->iotlb) {
ret = -EFAULT;
break;
}
ret = -EAGAIN;
break;
} else if (!(map->perm & access)) {
ret = -EPERM;
break;
}
_iov = iov + ret;
size = map->size - addr + map->start;
_iov->iov_len = min((u64)len - s, size);
_iov->iov_base = (void __user *)(unsigned long)
(map->addr + addr - map->start);
s += size;
addr += size;
++ret;
}
if (ret == -EAGAIN)
vhost_iotlb_miss(vq, addr, access);
return ret;
}
/* Each buffer in the virtqueues is actually a chain of descriptors. This
* function returns the next descriptor in the chain,
* or -1U if we're at the end. */
static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc)
{
unsigned int next;
/* If this descriptor says it doesn't chain, we're done. */
if (!(desc->flags & cpu_to_vhost16(vq, VRING_DESC_F_NEXT)))
return -1U;
/* Check they're not leading us off end of descriptors. */
next = vhost16_to_cpu(vq, READ_ONCE(desc->next));
return next;
}
static int get_indirect(struct vhost_virtqueue *vq,
struct iovec iov[], unsigned int iov_size,
unsigned int *out_num, unsigned int *in_num,
struct vhost_log *log, unsigned int *log_num,
struct vring_desc *indirect)
{
struct vring_desc desc;
unsigned int i = 0, count, found = 0;
u32 len = vhost32_to_cpu(vq, indirect->len);
struct iov_iter from;
int ret, access;
/* Sanity check */
if (unlikely(len % sizeof desc)) {
vq_err(vq, "Invalid length in indirect descriptor: "
"len 0x%llx not multiple of 0x%zx\n",
(unsigned long long)len,
sizeof desc);
return -EINVAL;
}
ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect,
UIO_MAXIOV, VHOST_ACCESS_RO);
if (unlikely(ret < 0)) {
if (ret != -EAGAIN)
vq_err(vq, "Translation failure %d in indirect.\n", ret);
return ret;
}
iov_iter_init(&from, ITER_SOURCE, vq->indirect, ret, len);
count = len / sizeof desc;
/* Buffers are chained via a 16 bit next field, so
* we can have at most 2^16 of these. */
if (unlikely(count > USHRT_MAX + 1)) {
vq_err(vq, "Indirect buffer length too big: %d\n",
indirect->len);
return -E2BIG;
}
do {
unsigned iov_count = *in_num + *out_num;
if (unlikely(++found > count)) {
vq_err(vq, "Loop detected: last one at %u "
"indirect size %u\n",
i, count);
return -EINVAL;
}
if (unlikely(!copy_from_iter_full(&desc, sizeof(desc), &from))) {
vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
return -EINVAL;
}
if (unlikely(desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT))) {
vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n",
i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
return -EINVAL;
}
if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
access = VHOST_ACCESS_WO;
else
access = VHOST_ACCESS_RO;
ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
vhost32_to_cpu(vq, desc.len), iov + iov_count,
iov_size - iov_count, access);
if (unlikely(ret < 0)) {
if (ret != -EAGAIN)
vq_err(vq, "Translation failure %d indirect idx %d\n",
ret, i);
return ret;
}
/* If this is an input descriptor, increment that count. */
if (access == VHOST_ACCESS_WO) {
*in_num += ret;
if (unlikely(log && ret)) {
log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
log[*log_num].len = vhost32_to_cpu(vq, desc.len);
++*log_num;
}
} else {
/* If it's an output descriptor, they're all supposed
* to come before any input descriptors. */
if (unlikely(*in_num)) {
vq_err(vq, "Indirect descriptor "
"has out after in: idx %d\n", i);
return -EINVAL;
}
*out_num += ret;
}
} while ((i = next_desc(vq, &desc)) != -1);
return 0;
}
/* This looks in the virtqueue and for the first available buffer, and converts
* it to an iovec for convenient access. Since descriptors consist of some
* number of output then some number of input descriptors, it's actually two
* iovecs, but we pack them into one and note how many of each there were.
*
* This function returns the descriptor number found, or vq->num (which is
* never a valid descriptor number) if none was found. A negative code is
* returned on error. */
int vhost_get_vq_desc(struct vhost_virtqueue *vq,
struct iovec iov[], unsigned int iov_size,
unsigned int *out_num, unsigned int *in_num,
struct vhost_log *log, unsigned int *log_num)
{
bool in_order = vhost_has_feature(vq, VIRTIO_F_IN_ORDER);
struct vring_desc desc;
unsigned int i, head, found = 0;
u16 last_avail_idx = vq->last_avail_idx;
__virtio16 ring_head;
int ret, access, c = 0;
if (vq->avail_idx == vq->last_avail_idx) {
ret = vhost_get_avail_idx(vq);
if (unlikely(ret < 0))
return ret;
if (!ret)
return vq->num;
}
if (in_order)
head = vq->next_avail_head & (vq->num - 1);
else {
/* Grab the next descriptor number they're
* advertising, and increment the index we've seen. */
if (unlikely(vhost_get_avail_head(vq, &ring_head,
last_avail_idx))) {
vq_err(vq, "Failed to read head: idx %d address %p\n",
last_avail_idx,
&vq->avail->ring[last_avail_idx % vq->num]);
return -EFAULT;
}
head = vhost16_to_cpu(vq, ring_head);
}
/* If their number is silly, that's an error. */
if (unlikely(head >= vq->num)) {
vq_err(vq, "Guest says index %u > %u is available",
head, vq->num);
return -EINVAL;
}
/* When we start there are none of either input nor output. */
*out_num = *in_num = 0;
if (unlikely(log))
*log_num = 0;
i = head;
do {
unsigned iov_count = *in_num + *out_num;
if (unlikely(i >= vq->num)) {
vq_err(vq, "Desc index is %u > %u, head = %u",
i, vq->num, head);
return -EINVAL;
}
if (unlikely(++found > vq->num)) {
vq_err(vq, "Loop detected: last one at %u "
"vq size %u head %u\n",
i, vq->num, head);
return -EINVAL;
}
ret = vhost_get_desc(vq, &desc, i);
if (unlikely(ret)) {
vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
i, vq->desc + i);
return -EFAULT;
}
if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) {
ret = get_indirect(vq, iov, iov_size,
out_num, in_num,
log, log_num, &desc);
if (unlikely(ret < 0)) {
if (ret != -EAGAIN)
vq_err(vq, "Failure detected "
"in indirect descriptor at idx %d\n", i);
return ret;
}
++c;
continue;
}
if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
access = VHOST_ACCESS_WO;
else
access = VHOST_ACCESS_RO;
ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
vhost32_to_cpu(vq, desc.len), iov + iov_count,
iov_size - iov_count, access);
if (unlikely(ret < 0)) {
if (ret != -EAGAIN)
vq_err(vq, "Translation failure %d descriptor idx %d\n",
ret, i);
return ret;
}
if (access == VHOST_ACCESS_WO) {
/* If this is an input descriptor,
* increment that count. */
*in_num += ret;
if (unlikely(log && ret)) {
log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
log[*log_num].len = vhost32_to_cpu(vq, desc.len);
++*log_num;
}
} else {
/* If it's an output descriptor, they're all supposed
* to come before any input descriptors. */
if (unlikely(*in_num)) {
vq_err(vq, "Descriptor has out after in: "
"idx %d\n", i);
return -EINVAL;
}
*out_num += ret;
}
++c;
} while ((i = next_desc(vq, &desc)) != -1);
/* On success, increment avail index. */
vq->last_avail_idx++;
vq->next_avail_head += c;
/* Assume notifications from guest are disabled at this point,
* if they aren't we would need to update avail_event index. */
BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
return head;
}
EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
/* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
{
vq->last_avail_idx -= n;
}
EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
/* After we've used one of their buffers, we tell them about it. We'll then
* want to notify the guest, using eventfd. */
int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
{
struct vring_used_elem heads = {
cpu_to_vhost32(vq, head),
cpu_to_vhost32(vq, len)
};
u16 nheads = 1;
return vhost_add_used_n(vq, &heads, &nheads, 1);
}
EXPORT_SYMBOL_GPL(vhost_add_used);
static int __vhost_add_used_n(struct vhost_virtqueue *vq,
struct vring_used_elem *heads,
unsigned count)
{
vring_used_elem_t __user *used;
u16 old, new;
int start;
start = vq->last_used_idx & (vq->num - 1);
used = vq->used->ring + start;
if (vhost_put_used(vq, heads, start, count)) {
vq_err(vq, "Failed to write used");
return -EFAULT;
}
if (unlikely(vq->log_used)) {
/* Make sure data is seen before log. */
smp_wmb();
/* Log used ring entry write. */
log_used(vq, ((void __user *)used - (void __user *)vq->used),
count * sizeof *used);
}
old = vq->last_used_idx;
new = (vq->last_used_idx += count);
/* If the driver never bothers to signal in a very long while,
* used index might wrap around. If that happens, invalidate
* signalled_used index we stored. TODO: make sure driver
* signals at least once in 2^16 and remove this. */
if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old)))
vq->signalled_used_valid = false;
return 0;
}
static int vhost_add_used_n_ooo(struct vhost_virtqueue *vq,
struct vring_used_elem *heads,
unsigned count)
{
int start, n, r;
start = vq->last_used_idx & (vq->num - 1);
n = vq->num - start;
if (n < count) {
r = __vhost_add_used_n(vq, heads, n);
if (r < 0)
return r;
heads += n;
count -= n;
}
return __vhost_add_used_n(vq, heads, count);
}
static int vhost_add_used_n_in_order(struct vhost_virtqueue *vq,
struct vring_used_elem *heads,
const u16 *nheads,
unsigned count)
{
vring_used_elem_t __user *used;
u16 old, new = vq->last_used_idx;
int start, i;
if (!nheads)
return -EINVAL;
start = vq->last_used_idx & (vq->num - 1);
used = vq->used->ring + start;
for (i = 0; i < count; i++) {
if (vhost_put_used(vq, &heads[i], start, 1)) {
vq_err(vq, "Failed to write used");
return -EFAULT;
}
start += nheads[i];
new += nheads[i];
if (start >= vq->num)
start -= vq->num;
}
if (unlikely(vq->log_used)) {
/* Make sure data is seen before log. */
smp_wmb();
/* Log used ring entry write. */
log_used(vq, ((void __user *)used - (void __user *)vq->used),
(vq->num - start) * sizeof *used);
if (start + count > vq->num)
log_used(vq, 0,
(start + count - vq->num) * sizeof *used);
}
old = vq->last_used_idx;
vq->last_used_idx = new;
/* If the driver never bothers to signal in a very long while,
* used index might wrap around. If that happens, invalidate
* signalled_used index we stored. TODO: make sure driver
* signals at least once in 2^16 and remove this. */
if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old)))
vq->signalled_used_valid = false;
return 0;
}
/* After we've used one of their buffers, we tell them about it. We'll then
* want to notify the guest, using eventfd. */
int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
u16 *nheads, unsigned count)
{
bool in_order = vhost_has_feature(vq, VIRTIO_F_IN_ORDER);
int r;
if (!in_order || !nheads)
r = vhost_add_used_n_ooo(vq, heads, count);
else
r = vhost_add_used_n_in_order(vq, heads, nheads, count);
if (r < 0)
return r;
/* Make sure buffer is written before we update index. */
smp_wmb();
if (vhost_put_used_idx(vq)) {
vq_err(vq, "Failed to increment used idx");
return -EFAULT;
}
if (unlikely(vq->log_used)) {
/* Make sure used idx is seen before log. */
smp_wmb();
/* Log used index update. */
log_used(vq, offsetof(struct vring_used, idx),
sizeof vq->used->idx);
if (vq->log_ctx)
eventfd_signal(vq->log_ctx);
}
return r;
}
EXPORT_SYMBOL_GPL(vhost_add_used_n);
static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
{
__u16 old, new;
__virtio16 event;
bool v;
/* Flush out used index updates. This is paired
* with the barrier that the Guest executes when enabling
* interrupts. */
smp_mb();
if (vhost_has_feature(vq, VIRTIO_F_NOTIFY_ON_EMPTY) &&
unlikely(vq->avail_idx == vq->last_avail_idx))
return true;
if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
__virtio16 flags;
if (vhost_get_avail_flags(vq, &flags)) {
vq_err(vq, "Failed to get flags");
return true;
}
return !(flags & cpu_to_vhost16(vq, VRING_AVAIL_F_NO_INTERRUPT));
}
old = vq->signalled_used;
v = vq->signalled_used_valid;
new = vq->signalled_used = vq->last_used_idx;
vq->signalled_used_valid = true;
if (unlikely(!v))
return true;
if (vhost_get_used_event(vq, &event)) {
vq_err(vq, "Failed to get used event idx");
return true;
}
return vring_need_event(vhost16_to_cpu(vq, event), new, old);
}
/* This actually signals the guest, using eventfd. */
void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
{
/* Signal the Guest tell them we used something up. */
if (vq->call_ctx.ctx && vhost_notify(dev, vq))
eventfd_signal(vq->call_ctx.ctx);
}
EXPORT_SYMBOL_GPL(vhost_signal);
/* And here's the combo meal deal. Supersize me! */
void vhost_add_used_and_signal(struct vhost_dev *dev,
struct vhost_virtqueue *vq,
unsigned int head, int len)
{
vhost_add_used(vq, head, len);
vhost_signal(dev, vq);
}
EXPORT_SYMBOL_GPL(vhost_add_used_and_signal);
/* multi-buffer version of vhost_add_used_and_signal */
void vhost_add_used_and_signal_n(struct vhost_dev *dev,
struct vhost_virtqueue *vq,
struct vring_used_elem *heads,
u16 *nheads,
unsigned count)
{
vhost_add_used_n(vq, heads, nheads, count);
vhost_signal(dev, vq);
}
EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
/* return true if we're sure that available ring is empty */
bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
{
int r;
if (vq->avail_idx != vq->last_avail_idx)
return false;
r = vhost_get_avail_idx(vq);
/* Note: we treat error as non-empty here */
return r == 0;
}
EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
/* OK, now we need to know about added descriptors. */
bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
{
int r;
if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
return false;
vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
r = vhost_update_used_flags(vq);
if (r) {
vq_err(vq, "Failed to enable notification at %p: %d\n",
&vq->used->flags, r);
return false;
}
} else {
r = vhost_update_avail_event(vq);
if (r) {
vq_err(vq, "Failed to update avail event index at %p: %d\n",
vhost_avail_event(vq), r);
return false;
}
}
/* They could have slipped one in as we were doing that: make
* sure it's written, then check again. */
smp_mb();
r = vhost_get_avail_idx(vq);
/* Note: we treat error as empty here */
if (unlikely(r < 0))
return false;
return r;
}
EXPORT_SYMBOL_GPL(vhost_enable_notify);
/* We don't need to be notified again. */
void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
{
int r;
if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
return;
vq->used_flags |= VRING_USED_F_NO_NOTIFY;
if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
r = vhost_update_used_flags(vq);
if (r)
vq_err(vq, "Failed to disable notification at %p: %d\n",
&vq->used->flags, r);
}
}
EXPORT_SYMBOL_GPL(vhost_disable_notify);
/* Create a new message. */
struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
{
/* Make sure all padding within the structure is initialized. */
struct vhost_msg_node *node = kzalloc(sizeof(*node), GFP_KERNEL);
if (!node)
return NULL;
node->vq = vq;
node->msg.type = type;
return node;
}
EXPORT_SYMBOL_GPL(vhost_new_msg);
void vhost_enqueue_msg(struct vhost_dev *dev, struct list_head *head,
struct vhost_msg_node *node)
{
spin_lock(&dev->iotlb_lock);
list_add_tail(&node->node, head);
spin_unlock(&dev->iotlb_lock);
wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
}
EXPORT_SYMBOL_GPL(vhost_enqueue_msg);
struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
struct list_head *head)
{
struct vhost_msg_node *node = NULL;
spin_lock(&dev->iotlb_lock);
if (!list_empty(head)) {
node = list_first_entry(head, struct vhost_msg_node,
node);
list_del(&node->node);
}
spin_unlock(&dev->iotlb_lock);
return node;
}
EXPORT_SYMBOL_GPL(vhost_dequeue_msg);
void vhost_set_backend_features(struct vhost_dev *dev, u64 features)
{
struct vhost_virtqueue *vq;
int i;
mutex_lock(&dev->mutex);
for (i = 0; i < dev->nvqs; ++i) {
vq = dev->vqs[i];
mutex_lock(&vq->mutex);
vq->acked_backend_features = features;
mutex_unlock(&vq->mutex);
}
mutex_unlock(&dev->mutex);
}
EXPORT_SYMBOL_GPL(vhost_set_backend_features);
static int __init vhost_init(void)
{
return 0;
}
static void __exit vhost_exit(void)
{
}
module_init(vhost_init);
module_exit(vhost_exit);
MODULE_VERSION("0.0.1");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Michael S. Tsirkin");
MODULE_DESCRIPTION("Host kernel accelerator for virtio");