| /* 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 |
| * |
| * This work is licensed under the terms of the GNU GPL, version 2. |
| * |
| * 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/mmu_context.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/interval_tree_generic.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)"); |
| |
| 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]) |
| |
| INTERVAL_TREE_DEFINE(struct vhost_umem_node, |
| rb, __u64, __subtree_last, |
| START, LAST, static inline, vhost_umem_interval_tree); |
| |
| #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); |
| |
| if (!(key_to_poll(key) & poll->mask)) |
| return 0; |
| |
| 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) |
| { |
| 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; |
| |
| 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; |
| int ret = 0; |
| |
| if (poll->wqh) |
| return 0; |
| |
| mask = file->f_op->poll(file, &poll->table); |
| if (mask) |
| vhost_poll_wakeup(&poll->wait, 0, 0, poll_to_key(mask)); |
| if (mask & EPOLLERR) { |
| vhost_poll_stop(poll); |
| ret = -EINVAL; |
| } |
| |
| return ret; |
| } |
| 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); |
| |
| void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work) |
| { |
| struct vhost_flush_struct flush; |
| |
| if (dev->worker) { |
| init_completion(&flush.wait_event); |
| vhost_work_init(&flush.work, vhost_flush_work); |
| |
| vhost_work_queue(dev, &flush.work); |
| wait_for_completion(&flush.wait_event); |
| } |
| } |
| EXPORT_SYMBOL_GPL(vhost_work_flush); |
| |
| /* Flush any work that has been scheduled. When calling this, don't hold any |
| * locks that are also used by the callback. */ |
| void vhost_poll_flush(struct vhost_poll *poll) |
| { |
| vhost_work_flush(poll->dev, &poll->work); |
| } |
| EXPORT_SYMBOL_GPL(vhost_poll_flush); |
| |
| void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work) |
| { |
| if (!dev->worker) |
| return; |
| |
| 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, &dev->work_list); |
| wake_up_process(dev->worker); |
| } |
| } |
| EXPORT_SYMBOL_GPL(vhost_work_queue); |
| |
| /* A lockless hint for busy polling code to exit the loop */ |
| bool vhost_has_work(struct vhost_dev *dev) |
| { |
| return !llist_empty(&dev->work_list); |
| } |
| EXPORT_SYMBOL_GPL(vhost_has_work); |
| |
| void vhost_poll_queue(struct vhost_poll *poll) |
| { |
| vhost_work_queue(poll->dev, &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_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->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; |
| vq->acked_features = 0; |
| vq->log_base = NULL; |
| vq->error_ctx = NULL; |
| vq->kick = NULL; |
| vq->call_ctx = NULL; |
| vq->log_ctx = NULL; |
| vhost_reset_is_le(vq); |
| vhost_disable_cross_endian(vq); |
| vq->busyloop_timeout = 0; |
| vq->umem = NULL; |
| vq->iotlb = NULL; |
| __vhost_vq_meta_reset(vq); |
| } |
| |
| static int vhost_worker(void *data) |
| { |
| struct vhost_dev *dev = data; |
| struct vhost_work *work, *work_next; |
| struct llist_node *node; |
| mm_segment_t oldfs = get_fs(); |
| |
| set_fs(USER_DS); |
| 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(&dev->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); |
| work->fn(work); |
| if (need_resched()) |
| schedule(); |
| } |
| } |
| unuse_mm(dev->mm); |
| set_fs(oldfs); |
| return 0; |
| } |
| |
| 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; |
| } |
| |
| /* 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(sizeof *vq->indirect * UIO_MAXIOV, |
| GFP_KERNEL); |
| vq->log = kmalloc(sizeof *vq->log * UIO_MAXIOV, GFP_KERNEL); |
| vq->heads = kmalloc(sizeof *vq->heads * UIO_MAXIOV, GFP_KERNEL); |
| if (!vq->indirect || !vq->log || !vq->heads) |
| 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]); |
| } |
| |
| void vhost_dev_init(struct vhost_dev *dev, |
| struct vhost_virtqueue **vqs, int nvqs) |
| { |
| 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->worker = NULL; |
| init_llist_head(&dev->work_list); |
| init_waitqueue_head(&dev->wait); |
| INIT_LIST_HEAD(&dev->read_list); |
| INIT_LIST_HEAD(&dev->pending_list); |
| spin_lock_init(&dev->iotlb_lock); |
| |
| |
| for (i = 0; i < dev->nvqs; ++i) { |
| vq = dev->vqs[i]; |
| vq->log = NULL; |
| vq->indirect = NULL; |
| vq->heads = 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); |
| } |
| } |
| 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_cgroups(struct vhost_dev *dev) |
| { |
| struct vhost_attach_cgroups_struct attach; |
| |
| attach.owner = current; |
| vhost_work_init(&attach.work, vhost_attach_cgroups_work); |
| vhost_work_queue(dev, &attach.work); |
| vhost_work_flush(dev, &attach.work); |
| 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); |
| |
| /* Caller should have device mutex */ |
| long vhost_dev_set_owner(struct vhost_dev *dev) |
| { |
| struct task_struct *worker; |
| int err; |
| |
| /* Is there an owner already? */ |
| if (vhost_dev_has_owner(dev)) { |
| err = -EBUSY; |
| goto err_mm; |
| } |
| |
| /* No owner, become one */ |
| dev->mm = get_task_mm(current); |
| worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid); |
| if (IS_ERR(worker)) { |
| err = PTR_ERR(worker); |
| goto err_worker; |
| } |
| |
| dev->worker = worker; |
| wake_up_process(worker); /* avoid contributing to loadavg */ |
| |
| err = vhost_attach_cgroups(dev); |
| if (err) |
| goto err_cgroup; |
| |
| err = vhost_dev_alloc_iovecs(dev); |
| if (err) |
| goto err_cgroup; |
| |
| return 0; |
| err_cgroup: |
| kthread_stop(worker); |
| dev->worker = NULL; |
| err_worker: |
| if (dev->mm) |
| mmput(dev->mm); |
| dev->mm = NULL; |
| err_mm: |
| return err; |
| } |
| EXPORT_SYMBOL_GPL(vhost_dev_set_owner); |
| |
| struct vhost_umem *vhost_dev_reset_owner_prepare(void) |
| { |
| return kvzalloc(sizeof(struct vhost_umem), GFP_KERNEL); |
| } |
| EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare); |
| |
| /* Caller should have device mutex */ |
| void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_umem *umem) |
| { |
| int i; |
| |
| vhost_dev_cleanup(dev); |
| |
| /* Restore memory to default empty mapping. */ |
| INIT_LIST_HEAD(&umem->umem_list); |
| 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_poll_flush(&dev->vqs[i]->poll); |
| } |
| } |
| } |
| EXPORT_SYMBOL_GPL(vhost_dev_stop); |
| |
| static void vhost_umem_free(struct vhost_umem *umem, |
| struct vhost_umem_node *node) |
| { |
| vhost_umem_interval_tree_remove(node, &umem->umem_tree); |
| list_del(&node->link); |
| kfree(node); |
| umem->numem--; |
| } |
| |
| static void vhost_umem_clean(struct vhost_umem *umem) |
| { |
| struct vhost_umem_node *node, *tmp; |
| |
| if (!umem) |
| return; |
| |
| list_for_each_entry_safe(node, tmp, &umem->umem_list, link) |
| vhost_umem_free(umem, node); |
| |
| kvfree(umem); |
| } |
| |
| static 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); |
| } |
| |
| 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) |
| eventfd_ctx_put(dev->vqs[i]->call_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_umem_clean(dev->umem); |
| dev->umem = NULL; |
| vhost_umem_clean(dev->iotlb); |
| dev->iotlb = NULL; |
| vhost_clear_msg(dev); |
| wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM); |
| WARN_ON(!llist_empty(&dev->work_list)); |
| if (dev->worker) { |
| kthread_stop(dev->worker); |
| dev->worker = NULL; |
| } |
| if (dev->mm) |
| mmput(dev->mm); |
| dev->mm = NULL; |
| } |
| 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(VERIFY_WRITE, log_base + a, |
| (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8); |
| } |
| |
| static bool vhost_overflow(u64 uaddr, u64 size) |
| { |
| /* Make sure 64 bit math will not overflow. */ |
| return uaddr > ULONG_MAX || size > ULONG_MAX || uaddr > ULONG_MAX - size; |
| } |
| |
| /* Caller should have vq mutex and device mutex. */ |
| static bool vq_memory_access_ok(void __user *log_base, struct vhost_umem *umem, |
| int log_all) |
| { |
| struct vhost_umem_node *node; |
| |
| if (!umem) |
| return false; |
| |
| list_for_each_entry(node, &umem->umem_list, link) { |
| unsigned long a = node->userspace_addr; |
| |
| if (vhost_overflow(node->userspace_addr, node->size)) |
| return false; |
| |
| |
| if (!access_ok(VERIFY_WRITE, (void __user *)a, |
| node->size)) |
| return false; |
| else if (log_all && !log_access_ok(log_base, |
| node->start, |
| node->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_umem_node *node = vq->meta_iotlb[type]; |
| |
| if (!node) |
| return NULL; |
| |
| return (void *)(uintptr_t)(node->userspace_addr + addr - node->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_umem *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, WRITE, 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, READ, 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 *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 = -EFAULT; \ |
| 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; \ |
| }) |
| |
| #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 int vhost_new_umem_range(struct vhost_umem *umem, |
| u64 start, u64 size, u64 end, |
| u64 userspace_addr, int perm) |
| { |
| struct vhost_umem_node *tmp, *node = kmalloc(sizeof(*node), GFP_ATOMIC); |
| |
| if (!node) |
| return -ENOMEM; |
| |
| if (umem->numem == max_iotlb_entries) { |
| tmp = list_first_entry(&umem->umem_list, typeof(*tmp), link); |
| vhost_umem_free(umem, tmp); |
| } |
| |
| node->start = start; |
| node->size = size; |
| node->last = end; |
| node->userspace_addr = userspace_addr; |
| node->perm = perm; |
| INIT_LIST_HEAD(&node->link); |
| list_add_tail(&node->link, &umem->umem_list); |
| vhost_umem_interval_tree_insert(node, &umem->umem_tree); |
| umem->numem++; |
| |
| return 0; |
| } |
| |
| static void vhost_del_umem_range(struct vhost_umem *umem, |
| u64 start, u64 end) |
| { |
| struct vhost_umem_node *node; |
| |
| while ((node = vhost_umem_interval_tree_iter_first(&umem->umem_tree, |
| start, end))) |
| vhost_umem_free(umem, node); |
| } |
| |
| 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(VERIFY_READ, (void __user *)a, size)) |
| return false; |
| if ((access & VHOST_ACCESS_WO) && |
| !access_ok(VERIFY_WRITE, (void __user *)a, size)) |
| return false; |
| return true; |
| } |
| |
| static int vhost_process_iotlb_msg(struct vhost_dev *dev, |
| struct vhost_iotlb_msg *msg) |
| { |
| int ret = 0; |
| |
| 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_new_umem_range(dev->iotlb, msg->iova, msg->size, |
| 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_del_umem_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_msg_node node; |
| unsigned size = sizeof(struct vhost_msg); |
| size_t ret; |
| int err; |
| |
| if (iov_iter_count(from) < size) |
| return 0; |
| ret = copy_from_iter(&node.msg, size, from); |
| if (ret != size) |
| goto done; |
| |
| switch (node.msg.type) { |
| case VHOST_IOTLB_MSG: |
| err = vhost_process_iotlb_msg(dev, &node.msg.iotlb); |
| if (err) |
| ret = err; |
| break; |
| default: |
| ret = -EINVAL; |
| break; |
| } |
| |
| 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) { |
| ret = copy_to_iter(&node->msg, size, to); |
| |
| if (ret != size || node->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; |
| |
| node = vhost_new_msg(vq, VHOST_IOTLB_MISS); |
| if (!node) |
| return -ENOMEM; |
| |
| 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, |
| struct vring_desc __user *desc, |
| struct vring_avail __user *avail, |
| struct vring_used __user *used) |
| |
| { |
| size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; |
| |
| return access_ok(VERIFY_READ, desc, num * sizeof *desc) && |
| access_ok(VERIFY_READ, avail, |
| sizeof *avail + num * sizeof *avail->ring + s) && |
| access_ok(VERIFY_WRITE, used, |
| sizeof *used + num * sizeof *used->ring + s); |
| } |
| |
| static void vhost_vq_meta_update(struct vhost_virtqueue *vq, |
| const struct vhost_umem_node *node, |
| int type) |
| { |
| int access = (type == VHOST_ADDR_USED) ? |
| VHOST_ACCESS_WO : VHOST_ACCESS_RO; |
| |
| if (likely(node->perm & access)) |
| vq->meta_iotlb[type] = node; |
| } |
| |
| static bool iotlb_access_ok(struct vhost_virtqueue *vq, |
| int access, u64 addr, u64 len, int type) |
| { |
| const struct vhost_umem_node *node; |
| struct vhost_umem *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) { |
| node = vhost_umem_interval_tree_iter_first(&umem->umem_tree, |
| addr, |
| last); |
| if (node == NULL || node->start > addr) { |
| vhost_iotlb_miss(vq, addr, access); |
| return false; |
| } else if (!(node->perm & access)) { |
| /* Report the possible access violation by |
| * request another translation from userspace. |
| */ |
| return false; |
| } |
| |
| size = node->size - addr + node->start; |
| |
| if (orig_addr == addr && size >= len) |
| vhost_vq_meta_update(vq, node, type); |
| |
| s += size; |
| addr += size; |
| } |
| |
| return true; |
| } |
| |
| int vq_iotlb_prefetch(struct vhost_virtqueue *vq) |
| { |
| size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; |
| unsigned int num = vq->num; |
| |
| if (!vq->iotlb) |
| return 1; |
| |
| return iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->desc, |
| num * sizeof(*vq->desc), VHOST_ADDR_DESC) && |
| iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->avail, |
| sizeof *vq->avail + |
| num * sizeof(*vq->avail->ring) + s, |
| VHOST_ADDR_AVAIL) && |
| iotlb_access_ok(vq, VHOST_ACCESS_WO, (u64)(uintptr_t)vq->used, |
| sizeof *vq->used + |
| num * sizeof(*vq->used->ring) + s, |
| VHOST_ADDR_USED); |
| } |
| EXPORT_SYMBOL_GPL(vq_iotlb_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); |
| |
| /* 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) |
| { |
| size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; |
| |
| return vq_memory_access_ok(log_base, vq->umem, |
| vhost_has_feature(vq, VHOST_F_LOG_ALL)) && |
| (!vq->log_used || log_access_ok(log_base, vq->log_addr, |
| sizeof *vq->used + |
| vq->num * sizeof *vq->used->ring + s)); |
| } |
| |
| /* 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; |
| |
| /* Access validation occurs at prefetch time with IOTLB */ |
| if (vq->iotlb) |
| return true; |
| |
| return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used); |
| } |
| EXPORT_SYMBOL_GPL(vhost_vq_access_ok); |
| |
| static struct vhost_umem *vhost_umem_alloc(void) |
| { |
| struct vhost_umem *umem = kvzalloc(sizeof(*umem), GFP_KERNEL); |
| |
| if (!umem) |
| return NULL; |
| |
| umem->umem_tree = RB_ROOT_CACHED; |
| umem->numem = 0; |
| INIT_LIST_HEAD(&umem->umem_list); |
| |
| return umem; |
| } |
| |
| 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_umem *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(size + mem.nregions * sizeof(*m->regions), GFP_KERNEL); |
| if (!newmem) |
| return -ENOMEM; |
| |
| memcpy(newmem, &mem, size); |
| if (copy_from_user(newmem->regions, m->regions, |
| mem.nregions * sizeof *m->regions)) { |
| kvfree(newmem); |
| return -EFAULT; |
| } |
| |
| newumem = vhost_umem_alloc(); |
| if (!newumem) { |
| kvfree(newmem); |
| return -ENOMEM; |
| } |
| |
| for (region = newmem->regions; |
| region < newmem->regions + mem.nregions; |
| region++) { |
| if (vhost_new_umem_range(newumem, |
| region->guest_phys_addr, |
| region->memory_size, |
| region->guest_phys_addr + |
| region->memory_size - 1, |
| region->userspace_addr, |
| VHOST_ACCESS_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_umem_clean(oldumem); |
| return 0; |
| |
| err: |
| vhost_umem_clean(newumem); |
| kvfree(newmem); |
| return -EFAULT; |
| } |
| |
| 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; |
| u32 __user *idxp = argp; |
| struct vhost_virtqueue *vq; |
| struct vhost_vring_state s; |
| struct vhost_vring_file f; |
| struct vhost_vring_addr a; |
| u32 idx; |
| long r; |
| |
| r = get_user(idx, idxp); |
| if (r < 0) |
| return r; |
| if (idx >= d->nvqs) |
| return -ENOBUFS; |
| |
| vq = d->vqs[idx]; |
| |
| mutex_lock(&vq->mutex); |
| |
| switch (ioctl) { |
| case VHOST_SET_VRING_NUM: |
| /* Resizing ring 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 (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) { |
| r = -EINVAL; |
| break; |
| } |
| vq->num = s.num; |
| break; |
| 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 (s.num > 0xffff) { |
| r = -EINVAL; |
| break; |
| } |
| 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; |
| s.num = vq->last_avail_idx; |
| if (copy_to_user(argp, &s, sizeof s)) |
| r = -EFAULT; |
| break; |
| case VHOST_SET_VRING_ADDR: |
| if (copy_from_user(&a, argp, sizeof a)) { |
| r = -EFAULT; |
| break; |
| } |
| if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) { |
| r = -EOPNOTSUPP; |
| break; |
| } |
| /* 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) { |
| r = -EFAULT; |
| break; |
| } |
| |
| /* 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))) { |
| r = -EINVAL; |
| break; |
| } |
| |
| /* 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)) { |
| r = -EINVAL; |
| break; |
| } |
| |
| /* Also validate log access for used ring if enabled. */ |
| if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) && |
| !log_access_ok(vq->log_base, a.log_guest_addr, |
| sizeof *vq->used + |
| vq->num * sizeof *vq->used->ring)) { |
| r = -EINVAL; |
| break; |
| } |
| } |
| |
| 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; |
| break; |
| case VHOST_SET_VRING_KICK: |
| if (copy_from_user(&f, argp, sizeof f)) { |
| r = -EFAULT; |
| break; |
| } |
| eventfp = f.fd == -1 ? 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 == -1 ? NULL : eventfd_ctx_fdget(f.fd); |
| if (IS_ERR(ctx)) { |
| r = PTR_ERR(ctx); |
| break; |
| } |
| swap(ctx, vq->call_ctx); |
| break; |
| case VHOST_SET_VRING_ERR: |
| if (copy_from_user(&f, argp, sizeof f)) { |
| r = -EFAULT; |
| break; |
| } |
| ctx = f.fd == -1 ? 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_poll_flush(&vq->poll); |
| return r; |
| } |
| EXPORT_SYMBOL_GPL(vhost_vring_ioctl); |
| |
| int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled) |
| { |
| struct vhost_umem *niotlb, *oiotlb; |
| int i; |
| |
| niotlb = vhost_umem_alloc(); |
| if (!niotlb) |
| return -ENOMEM; |
| |
| oiotlb = d->iotlb; |
| d->iotlb = niotlb; |
| |
| for (i = 0; i < d->nvqs; ++i) { |
| mutex_lock(&d->vqs[i]->mutex); |
| d->vqs[i]->iotlb = niotlb; |
| mutex_unlock(&d->vqs[i]->mutex); |
| } |
| |
| vhost_umem_clean(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; |
| } |
| |
| /* 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 == -1 ? 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/x86/exception-tables.txt. |
| */ |
| 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 = get_user_pages_fast(log, 1, 1, &page); |
| if (r < 0) |
| return r; |
| BUG_ON(r != 1); |
| base = kmap_atomic(page); |
| set_bit(bit, base); |
| kunmap_atomic(base); |
| set_page_dirty_lock(page); |
| put_page(page); |
| 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; |
| } |
| |
| int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, |
| unsigned int log_num, u64 len) |
| { |
| int i, r; |
| |
| /* Make sure data written is seen before log. */ |
| smp_wmb(); |
| 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; |
| len -= l; |
| if (!len) { |
| if (vq->log_ctx) |
| eventfd_signal(vq->log_ctx, 1); |
| return 0; |
| } |
| } |
| /* Length written exceeds what we have stored. This is a bug. */ |
| BUG(); |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(vhost_log_write); |
| |
| static int vhost_update_used_flags(struct vhost_virtqueue *vq) |
| { |
| void __user *used; |
| if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags), |
| &vq->used->flags) < 0) |
| 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_write(vq->log_base, vq->log_addr + |
| (used - (void __user *)vq->used), |
| sizeof vq->used->flags); |
| if (vq->log_ctx) |
| eventfd_signal(vq->log_ctx, 1); |
| } |
| return 0; |
| } |
| |
| static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event) |
| { |
| if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx), |
| vhost_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_write(vq->log_base, vq->log_addr + |
| (used - (void __user *)vq->used), |
| sizeof *vhost_avail_event(vq)); |
| if (vq->log_ctx) |
| eventfd_signal(vq->log_ctx, 1); |
| } |
| 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(VERIFY_READ, &vq->used->idx, sizeof vq->used->idx)) { |
| r = -EFAULT; |
| goto err; |
| } |
| r = vhost_get_used(vq, last_used_idx, &vq->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_umem_node *node; |
| struct vhost_dev *dev = vq->dev; |
| struct vhost_umem *umem = dev->iotlb ? dev->iotlb : dev->umem; |
| struct iovec *_iov; |
| u64 s = 0; |
| int ret = 0; |
| |
| while ((u64)len > s) { |
| u64 size; |
| if (unlikely(ret >= iov_size)) { |
| ret = -ENOBUFS; |
| break; |
| } |
| |
| node = vhost_umem_interval_tree_iter_first(&umem->umem_tree, |
| addr, addr + len - 1); |
| if (node == NULL || node->start > addr) { |
| if (umem != dev->iotlb) { |
| ret = -EFAULT; |
| break; |
| } |
| ret = -EAGAIN; |
| break; |
| } else if (!(node->perm & access)) { |
| ret = -EPERM; |
| break; |
| } |
| |
| _iov = iov + ret; |
| size = node->size - addr + node->start; |
| _iov->iov_len = min((u64)len - s, size); |
| _iov->iov_base = (void __user *)(unsigned long) |
| (node->userspace_addr + addr - node->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, READ, vq->indirect, ret, len); |
| |
| /* We will use the result as an address to read from, so most |
| * architectures only need a compiler barrier here. */ |
| read_barrier_depends(); |
| |
| 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)) { |
| 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) |
| { |
| struct vring_desc desc; |
| unsigned int i, head, found = 0; |
| u16 last_avail_idx; |
| __virtio16 avail_idx; |
| __virtio16 ring_head; |
| int ret, access; |
| |
| /* Check it isn't doing very strange things with descriptor numbers. */ |
| last_avail_idx = vq->last_avail_idx; |
| |
| if (vq->avail_idx == vq->last_avail_idx) { |
| if (unlikely(vhost_get_avail(vq, avail_idx, &vq->avail->idx))) { |
| vq_err(vq, "Failed to access avail idx at %p\n", |
| &vq->avail->idx); |
| return -EFAULT; |
| } |
| vq->avail_idx = vhost16_to_cpu(vq, avail_idx); |
| |
| if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) { |
| vq_err(vq, "Guest moved used index from %u to %u", |
| last_avail_idx, vq->avail_idx); |
| return -EFAULT; |
| } |
| |
| /* If there's nothing new since last we looked, return |
| * invalid. |
| */ |
| if (vq->avail_idx == last_avail_idx) |
| return vq->num; |
| |
| /* Only get avail ring entries after they have been |
| * exposed by guest. |
| */ |
| smp_rmb(); |
| } |
| |
| /* Grab the next descriptor number they're advertising, and increment |
| * the index we've seen. */ |
| if (unlikely(vhost_get_avail(vq, ring_head, |
| &vq->avail->ring[last_avail_idx & (vq->num - 1)]))) { |
| 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_copy_from_user(vq, &desc, vq->desc + i, |
| sizeof desc); |
| 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; |
| } |
| 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)) { |
| 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; |
| } |
| } while ((i = next_desc(vq, &desc)) != -1); |
| |
| /* On success, increment avail index. */ |
| vq->last_avail_idx++; |
| |
| /* 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) |
| }; |
| |
| return vhost_add_used_n(vq, &heads, 1); |
| } |
| EXPORT_SYMBOL_GPL(vhost_add_used); |
| |
| static int __vhost_add_used_n(struct vhost_virtqueue *vq, |
| struct vring_used_elem *heads, |
| unsigned count) |
| { |
| struct vring_used_elem __user *used; |
| u16 old, new; |
| int start; |
| |
| start = vq->last_used_idx & (vq->num - 1); |
| used = vq->used->ring + start; |
| if (count == 1) { |
| if (vhost_put_user(vq, heads[0].id, &used->id)) { |
| vq_err(vq, "Failed to write used id"); |
| return -EFAULT; |
| } |
| if (vhost_put_user(vq, heads[0].len, &used->len)) { |
| vq_err(vq, "Failed to write used len"); |
| return -EFAULT; |
| } |
| } else if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) { |
| 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_write(vq->log_base, |
| vq->log_addr + |
| ((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; |
| } |
| |
| /* 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, |
| 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; |
| } |
| r = __vhost_add_used_n(vq, heads, count); |
| |
| /* Make sure buffer is written before we update index. */ |
| smp_wmb(); |
| if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx), |
| &vq->used->idx)) { |
| vq_err(vq, "Failed to increment used idx"); |
| return -EFAULT; |
| } |
| if (unlikely(vq->log_used)) { |
| /* Log used index update. */ |
| log_write(vq->log_base, |
| vq->log_addr + offsetof(struct vring_used, idx), |
| sizeof vq->used->idx); |
| if (vq->log_ctx) |
| eventfd_signal(vq->log_ctx, 1); |
| } |
| 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(vq, flags, &vq->avail->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_avail(vq, event, vhost_used_event(vq))) { |
| 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 && vhost_notify(dev, vq)) |
| eventfd_signal(vq->call_ctx, 1); |
| } |
| 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, unsigned count) |
| { |
| vhost_add_used_n(vq, heads, count); |
| vhost_signal(dev, vq); |
| } |
| EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n); |
| |
| /* return true if we're sure that avaiable ring is empty */ |
| bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq) |
| { |
| __virtio16 avail_idx; |
| int r; |
| |
| if (vq->avail_idx != vq->last_avail_idx) |
| return false; |
| |
| r = vhost_get_avail(vq, avail_idx, &vq->avail->idx); |
| if (unlikely(r)) |
| return false; |
| vq->avail_idx = vhost16_to_cpu(vq, avail_idx); |
| |
| return vq->avail_idx == vq->last_avail_idx; |
| } |
| 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) |
| { |
| __virtio16 avail_idx; |
| 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, vq->avail_idx); |
| 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(vq, avail_idx, &vq->avail->idx); |
| if (r) { |
| vq_err(vq, "Failed to check avail idx at %p: %d\n", |
| &vq->avail->idx, r); |
| return false; |
| } |
| |
| return vhost16_to_cpu(vq, avail_idx) != vq->avail_idx; |
| } |
| 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 enable 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) |
| { |
| struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL); |
| if (!node) |
| return NULL; |
| |
| /* Make sure all padding within the structure is initialized. */ |
| memset(&node->msg, 0, sizeof node->msg); |
| 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); |
| |
| |
| 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"); |