diff options
Diffstat (limited to 'ANDROID_3.4.5/drivers/vhost/vhost.c')
| -rw-r--r-- | ANDROID_3.4.5/drivers/vhost/vhost.c | 1609 |
1 files changed, 0 insertions, 1609 deletions
diff --git a/ANDROID_3.4.5/drivers/vhost/vhost.c b/ANDROID_3.4.5/drivers/vhost/vhost.c deleted file mode 100644 index 51e4c1ee..00000000 --- a/ANDROID_3.4.5/drivers/vhost/vhost.c +++ /dev/null @@ -1,1609 +0,0 @@ -/* 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/virtio_net.h> -#include <linux/mm.h> -#include <linux/mmu_context.h> -#include <linux/miscdevice.h> -#include <linux/mutex.h> -#include <linux/rcupdate.h> -#include <linux/poll.h> -#include <linux/file.h> -#include <linux/highmem.h> -#include <linux/slab.h> -#include <linux/kthread.h> -#include <linux/cgroup.h> - -#include <linux/net.h> -#include <linux/if_packet.h> -#include <linux/if_arp.h> - -#include "vhost.h" - -enum { - VHOST_MEMORY_MAX_NREGIONS = 64, - VHOST_MEMORY_F_LOG = 0x1, -}; - -static unsigned vhost_zcopy_mask __read_mostly; - -#define vhost_used_event(vq) ((u16 __user *)&vq->avail->ring[vq->num]) -#define vhost_avail_event(vq) ((u16 __user *)&vq->used->ring[vq->num]) - -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_t *wait, unsigned mode, int sync, - void *key) -{ - struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait); - - if (!((unsigned long)key & poll->mask)) - return 0; - - vhost_poll_queue(poll); - return 0; -} - -static void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn) -{ - INIT_LIST_HEAD(&work->node); - work->fn = fn; - init_waitqueue_head(&work->done); - work->flushing = 0; - work->queue_seq = work->done_seq = 0; -} - -/* Init poll structure */ -void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, - unsigned long 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; - - vhost_work_init(&poll->work, fn); -} - -/* 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. */ -void vhost_poll_start(struct vhost_poll *poll, struct file *file) -{ - unsigned long mask; - - mask = file->f_op->poll(file, &poll->table); - if (mask) - vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask); -} - -/* 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) -{ - remove_wait_queue(poll->wqh, &poll->wait); -} - -static bool vhost_work_seq_done(struct vhost_dev *dev, struct vhost_work *work, - unsigned seq) -{ - int left; - - spin_lock_irq(&dev->work_lock); - left = seq - work->done_seq; - spin_unlock_irq(&dev->work_lock); - return left <= 0; -} - -static void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work) -{ - unsigned seq; - int flushing; - - spin_lock_irq(&dev->work_lock); - seq = work->queue_seq; - work->flushing++; - spin_unlock_irq(&dev->work_lock); - wait_event(work->done, vhost_work_seq_done(dev, work, seq)); - spin_lock_irq(&dev->work_lock); - flushing = --work->flushing; - spin_unlock_irq(&dev->work_lock); - BUG_ON(flushing < 0); -} - -/* 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); -} - -static inline void vhost_work_queue(struct vhost_dev *dev, - struct vhost_work *work) -{ - unsigned long flags; - - spin_lock_irqsave(&dev->work_lock, flags); - if (list_empty(&work->node)) { - list_add_tail(&work->node, &dev->work_list); - work->queue_seq++; - wake_up_process(dev->worker); - } - spin_unlock_irqrestore(&dev->work_lock, flags); -} - -void vhost_poll_queue(struct vhost_poll *poll) -{ - vhost_work_queue(poll->dev, &poll->work); -} - -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->vhost_hlen = 0; - vq->sock_hlen = 0; - vq->private_data = NULL; - vq->log_base = NULL; - vq->error_ctx = NULL; - vq->error = NULL; - vq->kick = NULL; - vq->call_ctx = NULL; - vq->call = NULL; - vq->log_ctx = NULL; - vq->upend_idx = 0; - vq->done_idx = 0; - vq->ubufs = NULL; -} - -static int vhost_worker(void *data) -{ - struct vhost_dev *dev = data; - struct vhost_work *work = NULL; - unsigned uninitialized_var(seq); - - use_mm(dev->mm); - - for (;;) { - /* mb paired w/ kthread_stop */ - set_current_state(TASK_INTERRUPTIBLE); - - spin_lock_irq(&dev->work_lock); - if (work) { - work->done_seq = seq; - if (work->flushing) - wake_up_all(&work->done); - } - - if (kthread_should_stop()) { - spin_unlock_irq(&dev->work_lock); - __set_current_state(TASK_RUNNING); - break; - } - if (!list_empty(&dev->work_list)) { - work = list_first_entry(&dev->work_list, - struct vhost_work, node); - list_del_init(&work->node); - seq = work->queue_seq; - } else - work = NULL; - spin_unlock_irq(&dev->work_lock); - - if (work) { - __set_current_state(TASK_RUNNING); - work->fn(work); - if (need_resched()) - schedule(); - } else - schedule(); - - } - unuse_mm(dev->mm); - 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; - kfree(vq->ubuf_info); - vq->ubuf_info = NULL; -} - -void vhost_enable_zcopy(int vq) -{ - vhost_zcopy_mask |= 0x1 << vq; -} - -/* Helper to allocate iovec buffers for all vqs. */ -static long vhost_dev_alloc_iovecs(struct vhost_dev *dev) -{ - int i; - bool zcopy; - - for (i = 0; i < dev->nvqs; ++i) { - dev->vqs[i].indirect = kmalloc(sizeof *dev->vqs[i].indirect * - UIO_MAXIOV, GFP_KERNEL); - dev->vqs[i].log = kmalloc(sizeof *dev->vqs[i].log * UIO_MAXIOV, - GFP_KERNEL); - dev->vqs[i].heads = kmalloc(sizeof *dev->vqs[i].heads * - UIO_MAXIOV, GFP_KERNEL); - zcopy = vhost_zcopy_mask & (0x1 << i); - if (zcopy) - dev->vqs[i].ubuf_info = - kmalloc(sizeof *dev->vqs[i].ubuf_info * - UIO_MAXIOV, GFP_KERNEL); - if (!dev->vqs[i].indirect || !dev->vqs[i].log || - !dev->vqs[i].heads || - (zcopy && !dev->vqs[i].ubuf_info)) - 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]); -} - -long vhost_dev_init(struct vhost_dev *dev, - struct vhost_virtqueue *vqs, int nvqs) -{ - int i; - - dev->vqs = vqs; - dev->nvqs = nvqs; - mutex_init(&dev->mutex); - dev->log_ctx = NULL; - dev->log_file = NULL; - dev->memory = NULL; - dev->mm = NULL; - spin_lock_init(&dev->work_lock); - INIT_LIST_HEAD(&dev->work_list); - dev->worker = NULL; - - for (i = 0; i < dev->nvqs; ++i) { - dev->vqs[i].log = NULL; - dev->vqs[i].indirect = NULL; - dev->vqs[i].heads = NULL; - dev->vqs[i].ubuf_info = NULL; - dev->vqs[i].dev = dev; - mutex_init(&dev->vqs[i].mutex); - vhost_vq_reset(dev, dev->vqs + i); - if (dev->vqs[i].handle_kick) - vhost_poll_init(&dev->vqs[i].poll, - dev->vqs[i].handle_kick, POLLIN, dev); - } - - return 0; -} - -/* 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; -} - -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 */ -static long vhost_dev_set_owner(struct vhost_dev *dev) -{ - struct task_struct *worker; - int err; - - /* Is there an owner already? */ - if (dev->mm) { - 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; -} - -/* Caller should have device mutex */ -long vhost_dev_reset_owner(struct vhost_dev *dev) -{ - struct vhost_memory *memory; - - /* Restore memory to default empty mapping. */ - memory = kmalloc(offsetof(struct vhost_memory, regions), GFP_KERNEL); - if (!memory) - return -ENOMEM; - - vhost_dev_cleanup(dev, true); - - memory->nregions = 0; - RCU_INIT_POINTER(dev->memory, memory); - return 0; -} - -/* In case of DMA done not in order in lower device driver for some reason. - * upend_idx is used to track end of used idx, done_idx is used to track head - * of used idx. Once lower device DMA done contiguously, we will signal KVM - * guest used idx. - */ -int vhost_zerocopy_signal_used(struct vhost_virtqueue *vq) -{ - int i; - int j = 0; - - for (i = vq->done_idx; i != vq->upend_idx; i = (i + 1) % UIO_MAXIOV) { - if ((vq->heads[i].len == VHOST_DMA_DONE_LEN)) { - vq->heads[i].len = VHOST_DMA_CLEAR_LEN; - vhost_add_used_and_signal(vq->dev, vq, - vq->heads[i].id, 0); - ++j; - } else - break; - } - if (j) - vq->done_idx = i; - return j; -} - -/* Caller should have device mutex if and only if locked is set */ -void vhost_dev_cleanup(struct vhost_dev *dev, bool locked) -{ - 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); - } - /* Wait for all lower device DMAs done. */ - if (dev->vqs[i].ubufs) - vhost_ubuf_put_and_wait(dev->vqs[i].ubufs); - - /* Signal guest as appropriate. */ - vhost_zerocopy_signal_used(&dev->vqs[i]); - - if (dev->vqs[i].error_ctx) - eventfd_ctx_put(dev->vqs[i].error_ctx); - if (dev->vqs[i].error) - fput(dev->vqs[i].error); - if (dev->vqs[i].kick) - fput(dev->vqs[i].kick); - if (dev->vqs[i].call_ctx) - eventfd_ctx_put(dev->vqs[i].call_ctx); - if (dev->vqs[i].call) - fput(dev->vqs[i].call); - 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; - if (dev->log_file) - fput(dev->log_file); - dev->log_file = NULL; - /* No one will access memory at this point */ - kfree(rcu_dereference_protected(dev->memory, - locked == - lockdep_is_held(&dev->mutex))); - RCU_INIT_POINTER(dev->memory, NULL); - WARN_ON(!list_empty(&dev->work_list)); - if (dev->worker) { - kthread_stop(dev->worker); - dev->worker = NULL; - } - if (dev->mm) - mmput(dev->mm); - dev->mm = NULL; -} - -static int 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 0; - - return access_ok(VERIFY_WRITE, log_base + a, - (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8); -} - -/* Caller should have vq mutex and device mutex. */ -static int vq_memory_access_ok(void __user *log_base, struct vhost_memory *mem, - int log_all) -{ - int i; - - if (!mem) - return 0; - - for (i = 0; i < mem->nregions; ++i) { - struct vhost_memory_region *m = mem->regions + i; - unsigned long a = m->userspace_addr; - if (m->memory_size > ULONG_MAX) - return 0; - else if (!access_ok(VERIFY_WRITE, (void __user *)a, - m->memory_size)) - return 0; - else if (log_all && !log_access_ok(log_base, - m->guest_phys_addr, - m->memory_size)) - return 0; - } - return 1; -} - -/* Can we switch to this memory table? */ -/* Caller should have device mutex but not vq mutex */ -static int memory_access_ok(struct vhost_dev *d, struct vhost_memory *mem, - int log_all) -{ - int i; - - for (i = 0; i < d->nvqs; ++i) { - int ok; - mutex_lock(&d->vqs[i].mutex); - /* 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, mem, - log_all); - else - ok = 1; - mutex_unlock(&d->vqs[i].mutex); - if (!ok) - return 0; - } - return 1; -} - -static int vq_access_ok(struct vhost_dev *d, unsigned int num, - struct vring_desc __user *desc, - struct vring_avail __user *avail, - struct vring_used __user *used) -{ - size_t s = vhost_has_feature(d, 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); -} - -/* Can we log writes? */ -/* Caller should have device mutex but not vq mutex */ -int vhost_log_access_ok(struct vhost_dev *dev) -{ - struct vhost_memory *mp; - - mp = rcu_dereference_protected(dev->memory, - lockdep_is_held(&dev->mutex)); - return memory_access_ok(dev, mp, 1); -} - -/* Verify access for write logging. */ -/* Caller should have vq mutex and device mutex */ -static int vq_log_access_ok(struct vhost_dev *d, struct vhost_virtqueue *vq, - void __user *log_base) -{ - struct vhost_memory *mp; - size_t s = vhost_has_feature(d, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; - - mp = rcu_dereference_protected(vq->dev->memory, - lockdep_is_held(&vq->mutex)); - return vq_memory_access_ok(log_base, mp, - vhost_has_feature(vq->dev, 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 */ -int vhost_vq_access_ok(struct vhost_virtqueue *vq) -{ - return vq_access_ok(vq->dev, vq->num, vq->desc, vq->avail, vq->used) && - vq_log_access_ok(vq->dev, vq, vq->log_base); -} - -static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) -{ - struct vhost_memory mem, *newmem, *oldmem; - unsigned long size = offsetof(struct vhost_memory, regions); - - if (copy_from_user(&mem, m, size)) - return -EFAULT; - if (mem.padding) - return -EOPNOTSUPP; - if (mem.nregions > VHOST_MEMORY_MAX_NREGIONS) - return -E2BIG; - newmem = kmalloc(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)) { - kfree(newmem); - return -EFAULT; - } - - if (!memory_access_ok(d, newmem, - vhost_has_feature(d, VHOST_F_LOG_ALL))) { - kfree(newmem); - return -EFAULT; - } - oldmem = rcu_dereference_protected(d->memory, - lockdep_is_held(&d->mutex)); - rcu_assign_pointer(d->memory, newmem); - synchronize_rcu(); - kfree(oldmem); - return 0; -} - -static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp) -{ - struct file *eventfp, *filep = NULL, - *pollstart = NULL, *pollstop = NULL; - 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; - } - if ((a.avail_user_addr & (sizeof *vq->avail->ring - 1)) || - (a.used_user_addr & (sizeof *vq->used->ring - 1)) || - (a.log_guest_addr & (sizeof *vq->used->ring - 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(d, 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; - pollstart = vq->kick = eventfp; - } else - filep = eventfp; - break; - case VHOST_SET_VRING_CALL: - 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->call) { - filep = vq->call; - ctx = vq->call_ctx; - vq->call = eventfp; - vq->call_ctx = eventfp ? - eventfd_ctx_fileget(eventfp) : NULL; - } else - filep = eventfp; - break; - case VHOST_SET_VRING_ERR: - 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->error) { - filep = vq->error; - vq->error = eventfp; - ctx = vq->error_ctx; - vq->error_ctx = eventfp ? - eventfd_ctx_fileget(eventfp) : NULL; - } else - filep = eventfp; - break; - default: - r = -ENOIOCTLCMD; - } - - if (pollstop && vq->handle_kick) - vhost_poll_stop(&vq->poll); - - if (ctx) - eventfd_ctx_put(ctx); - if (filep) - fput(filep); - - if (pollstart && vq->handle_kick) - vhost_poll_start(&vq->poll, vq->kick); - - mutex_unlock(&vq->mutex); - - if (pollstop && vq->handle_kick) - vhost_poll_flush(&vq->poll); - return r; -} - -/* Caller must have device mutex */ -long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, unsigned long arg) -{ - void __user *argp = (void __user *)arg; - struct file *eventfp, *filep = NULL; - struct eventfd_ctx *ctx = NULL; - 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(d, 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; - eventfp = fd == -1 ? NULL : eventfd_fget(fd); - if (IS_ERR(eventfp)) { - r = PTR_ERR(eventfp); - break; - } - if (eventfp != d->log_file) { - filep = d->log_file; - ctx = d->log_ctx; - d->log_ctx = eventfp ? - eventfd_ctx_fileget(eventfp) : NULL; - } else - filep = eventfp; - 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); - if (filep) - fput(filep); - break; - default: - r = vhost_set_vring(d, ioctl, argp); - break; - } -done: - return r; -} - -static const struct vhost_memory_region *find_region(struct vhost_memory *mem, - __u64 addr, __u32 len) -{ - struct vhost_memory_region *reg; - int i; - - /* linear search is not brilliant, but we really have on the order of 6 - * regions in practice */ - for (i = 0; i < mem->nregions; ++i) { - reg = mem->regions + i; - if (reg->guest_phys_addr <= addr && - reg->guest_phys_addr + reg->memory_size - 1 >= addr) - return reg; - } - return NULL; -} - -/* 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; -} - -static int vhost_update_used_flags(struct vhost_virtqueue *vq) -{ - void __user *used; - if (__put_user(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 (__put_user(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_init_used(struct vhost_virtqueue *vq) -{ - int r; - if (!vq->private_data) - return 0; - - r = vhost_update_used_flags(vq); - if (r) - return r; - vq->signalled_used_valid = false; - return get_user(vq->last_used_idx, &vq->used->idx); -} - -static int translate_desc(struct vhost_dev *dev, u64 addr, u32 len, - struct iovec iov[], int iov_size) -{ - const struct vhost_memory_region *reg; - struct vhost_memory *mem; - struct iovec *_iov; - u64 s = 0; - int ret = 0; - - rcu_read_lock(); - - mem = rcu_dereference(dev->memory); - while ((u64)len > s) { - u64 size; - if (unlikely(ret >= iov_size)) { - ret = -ENOBUFS; - break; - } - reg = find_region(mem, addr, len); - if (unlikely(!reg)) { - ret = -EFAULT; - break; - } - _iov = iov + ret; - size = reg->memory_size - addr + reg->guest_phys_addr; - _iov->iov_len = min((u64)len, size); - _iov->iov_base = (void __user *)(unsigned long) - (reg->userspace_addr + addr - reg->guest_phys_addr); - s += size; - addr += size; - ++ret; - } - - rcu_read_unlock(); - 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 vring_desc *desc) -{ - unsigned int next; - - /* If this descriptor says it doesn't chain, we're done. */ - if (!(desc->flags & VRING_DESC_F_NEXT)) - return -1U; - - /* Check they're not leading us off end of descriptors. */ - next = desc->next; - /* Make sure compiler knows to grab that: we don't want it changing! */ - /* We will use the result as an index in an array, so most - * architectures only need a compiler barrier here. */ - read_barrier_depends(); - - return next; -} - -static int get_indirect(struct vhost_dev *dev, 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; - int ret; - - /* Sanity check */ - if (unlikely(indirect->len % sizeof desc)) { - vq_err(vq, "Invalid length in indirect descriptor: " - "len 0x%llx not multiple of 0x%zx\n", - (unsigned long long)indirect->len, - sizeof desc); - return -EINVAL; - } - - ret = translate_desc(dev, indirect->addr, indirect->len, vq->indirect, - UIO_MAXIOV); - if (unlikely(ret < 0)) { - vq_err(vq, "Translation failure %d in indirect.\n", ret); - return ret; - } - - /* We will use the result as an address to read from, so most - * architectures only need a compiler barrier here. */ - read_barrier_depends(); - - count = indirect->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(memcpy_fromiovec((unsigned char *)&desc, - vq->indirect, sizeof desc))) { - vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n", - i, (size_t)indirect->addr + i * sizeof desc); - return -EINVAL; - } - if (unlikely(desc.flags & VRING_DESC_F_INDIRECT)) { - vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n", - i, (size_t)indirect->addr + i * sizeof desc); - return -EINVAL; - } - - ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, - iov_size - iov_count); - if (unlikely(ret < 0)) { - vq_err(vq, "Translation failure %d indirect idx %d\n", - ret, i); - return ret; - } - /* If this is an input descriptor, increment that count. */ - if (desc.flags & VRING_DESC_F_WRITE) { - *in_num += ret; - if (unlikely(log)) { - log[*log_num].addr = desc.addr; - log[*log_num].len = 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(&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_dev *dev, 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; - int ret; - - /* Check it isn't doing very strange things with descriptor numbers. */ - last_avail_idx = vq->last_avail_idx; - if (unlikely(__get_user(vq->avail_idx, &vq->avail->idx))) { - vq_err(vq, "Failed to access avail idx at %p\n", - &vq->avail->idx); - return -EFAULT; - } - - 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(__get_user(head, - &vq->avail->ring[last_avail_idx % vq->num]))) { - 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; - } - - /* 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 = __copy_from_user(&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 & VRING_DESC_F_INDIRECT) { - ret = get_indirect(dev, vq, iov, iov_size, - out_num, in_num, - log, log_num, &desc); - if (unlikely(ret < 0)) { - vq_err(vq, "Failure detected " - "in indirect descriptor at idx %d\n", i); - return ret; - } - continue; - } - - ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count, - iov_size - iov_count); - if (unlikely(ret < 0)) { - vq_err(vq, "Translation failure %d descriptor idx %d\n", - ret, i); - return ret; - } - if (desc.flags & VRING_DESC_F_WRITE) { - /* If this is an input descriptor, - * increment that count. */ - *in_num += ret; - if (unlikely(log)) { - log[*log_num].addr = desc.addr; - log[*log_num].len = 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(&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; -} - -/* 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; -} - -/* 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 __user *used; - - /* The virtqueue contains a ring of used buffers. Get a pointer to the - * next entry in that used ring. */ - used = &vq->used->ring[vq->last_used_idx % vq->num]; - if (__put_user(head, &used->id)) { - vq_err(vq, "Failed to write used id"); - return -EFAULT; - } - if (__put_user(len, &used->len)) { - vq_err(vq, "Failed to write used len"); - return -EFAULT; - } - /* Make sure buffer is written before we update index. */ - smp_wmb(); - if (__put_user(vq->last_used_idx + 1, &vq->used->idx)) { - vq_err(vq, "Failed to increment used idx"); - 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), - sizeof *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); - } - vq->last_used_idx++; - /* 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(vq->last_used_idx == vq->signalled_used)) - vq->signalled_used_valid = false; - return 0; -} - -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; - used = vq->used->ring + start; - if (__copy_to_user(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; - 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 (put_user(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; -} - -static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) -{ - __u16 old, new, 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(dev, VIRTIO_F_NOTIFY_ON_EMPTY) && - unlikely(vq->avail_idx == vq->last_avail_idx)) - return true; - - if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) { - __u16 flags; - if (__get_user(flags, &vq->avail->flags)) { - vq_err(vq, "Failed to get flags"); - return true; - } - return !(flags & 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 (get_user(event, vhost_used_event(vq))) { - vq_err(vq, "Failed to get used event idx"); - return true; - } - return vring_need_event(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); -} - -/* 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); -} - -/* 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); -} - -/* OK, now we need to know about added descriptors. */ -bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) -{ - u16 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(dev, 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 = __get_user(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 avail_idx != vq->avail_idx; -} - -/* 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(dev, 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); - } -} - -static void vhost_zerocopy_done_signal(struct kref *kref) -{ - struct vhost_ubuf_ref *ubufs = container_of(kref, struct vhost_ubuf_ref, - kref); - wake_up(&ubufs->wait); -} - -struct vhost_ubuf_ref *vhost_ubuf_alloc(struct vhost_virtqueue *vq, - bool zcopy) -{ - struct vhost_ubuf_ref *ubufs; - /* No zero copy backend? Nothing to count. */ - if (!zcopy) - return NULL; - ubufs = kmalloc(sizeof *ubufs, GFP_KERNEL); - if (!ubufs) - return ERR_PTR(-ENOMEM); - kref_init(&ubufs->kref); - init_waitqueue_head(&ubufs->wait); - ubufs->vq = vq; - return ubufs; -} - -void vhost_ubuf_put(struct vhost_ubuf_ref *ubufs) -{ - kref_put(&ubufs->kref, vhost_zerocopy_done_signal); -} - -void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *ubufs) -{ - kref_put(&ubufs->kref, vhost_zerocopy_done_signal); - wait_event(ubufs->wait, !atomic_read(&ubufs->kref.refcount)); - kfree(ubufs); -} - -void vhost_zerocopy_callback(struct ubuf_info *ubuf) -{ - struct vhost_ubuf_ref *ubufs = ubuf->ctx; - struct vhost_virtqueue *vq = ubufs->vq; - - /* set len = 1 to mark this desc buffers done DMA */ - vq->heads[ubuf->desc].len = VHOST_DMA_DONE_LEN; - kref_put(&ubufs->kref, vhost_zerocopy_done_signal); -} |