From 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 Mon Sep 17 00:00:00 2001 From: Yunhong Jiang Date: Tue, 4 Aug 2015 12:17:53 -0700 Subject: Add the rt linux 4.1.3-rt3 as base Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang --- kernel/drivers/vhost/vhost.c | 1583 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1583 insertions(+) create mode 100644 kernel/drivers/vhost/vhost.c (limited to 'kernel/drivers/vhost/vhost.c') diff --git a/kernel/drivers/vhost/vhost.c b/kernel/drivers/vhost/vhost.c new file mode 100644 index 000000000..2ee28266f --- /dev/null +++ b/kernel/drivers/vhost/vhost.c @@ -0,0 +1,1583 @@ +/* Copyright (C) 2009 Red Hat, Inc. + * Copyright (C) 2006 Rusty Russell IBM Corporation + * + * Author: Michael S. Tsirkin + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "vhost.h" + +enum { + VHOST_MEMORY_MAX_NREGIONS = 64, + 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]) + +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; +} + +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; +} +EXPORT_SYMBOL_GPL(vhost_work_init); + +/* 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; + 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) +{ + unsigned long 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, (void *)mask); + if (mask & POLLERR) { + if (poll->wqh) + remove_wait_queue(poll->wqh, &poll->wait); + 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); + +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; +} + +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); +} +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) +{ + 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++; + spin_unlock_irqrestore(&dev->work_lock, flags); + wake_up_process(dev->worker); + } else { + spin_unlock_irqrestore(&dev->work_lock, flags); + } +} +EXPORT_SYMBOL_GPL(vhost_work_queue); + +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_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->error = NULL; + vq->kick = NULL; + vq->call_ctx = NULL; + vq->call = NULL; + vq->log_ctx = NULL; + vq->memory = NULL; +} + +static int vhost_worker(void *data) +{ + struct vhost_dev *dev = data; + struct vhost_work *work = NULL; + unsigned uninitialized_var(seq); + 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); + + 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); + 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->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) { + 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, + POLLIN, 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_memory *vhost_dev_reset_owner_prepare(void) +{ + return kmalloc(offsetof(struct vhost_memory, regions), 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_memory *memory) +{ + int i; + + vhost_dev_cleanup(dev, true); + + /* Restore memory to default empty mapping. */ + memory->nregions = 0; + dev->memory = memory; + /* 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]->memory = memory; +} +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); + +/* 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]->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(dev->memory); + 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; +} +EXPORT_SYMBOL_GPL(vhost_dev_cleanup); + +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; + 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, mem, log); + else + ok = 1; + mutex_unlock(&d->vqs[i]->mutex); + if (!ok) + return 0; + } + return 1; +} + +static int 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); +} + +/* Can we log writes? */ +/* Caller should have device mutex but not vq mutex */ +int vhost_log_access_ok(struct vhost_dev *dev) +{ + return memory_access_ok(dev, dev->memory, 1); +} +EXPORT_SYMBOL_GPL(vhost_log_access_ok); + +/* Verify access for write logging. */ +/* Caller should have vq mutex and device mutex */ +static int 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->memory, + 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 */ +int vhost_vq_access_ok(struct vhost_virtqueue *vq) +{ + return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used) && + vq_log_access_ok(vq, vq->log_base); +} +EXPORT_SYMBOL_GPL(vhost_vq_access_ok); + +static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) +{ + struct vhost_memory mem, *newmem, *oldmem; + 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 > 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, 0)) { + kfree(newmem); + return -EFAULT; + } + oldmem = d->memory; + d->memory = newmem; + + /* 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]->memory = newmem; + mutex_unlock(&d->vqs[i]->mutex); + } + kfree(oldmem); + return 0; +} + +long vhost_vring_ioctl(struct vhost_dev *d, 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 & (sizeof(u64) - 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; + } + 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) + 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); + +/* Caller must have device mutex */ +long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp) +{ + 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(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 = -ENOIOCTLCMD; + break; + } +done: + return r; +} +EXPORT_SYMBOL_GPL(vhost_dev_ioctl); + +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; +} +EXPORT_SYMBOL_GPL(vhost_log_write); + +static int vhost_update_used_flags(struct vhost_virtqueue *vq) +{ + void __user *used; + if (__put_user(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 (__put_user(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_init_used(struct vhost_virtqueue *vq) +{ + __virtio16 last_used_idx; + int r; + if (!vq->private_data) + return 0; + + r = vhost_update_used_flags(vq); + if (r) + return r; + vq->signalled_used_valid = false; + if (!access_ok(VERIFY_READ, &vq->used->idx, sizeof vq->used->idx)) + return -EFAULT; + r = __get_user(last_used_idx, &vq->used->idx); + if (r) + return r; + vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx); + return 0; +} +EXPORT_SYMBOL_GPL(vhost_init_used); + +static int translate_desc(struct vhost_virtqueue *vq, 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; + + mem = vq->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 - s, size); + _iov->iov_base = (void __user *)(unsigned long) + (reg->userspace_addr + addr - reg->guest_phys_addr); + s += size; + addr += size; + ++ret; + } + + 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, 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_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; + + /* 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); + if (unlikely(ret < 0)) { + 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(&desc, sizeof(desc), &from) != + sizeof(desc))) { + 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; + } + + ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr), + vhost32_to_cpu(vq, 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 & cpu_to_vhost16(vq, VRING_DESC_F_WRITE)) { + *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; + + /* Check it isn't doing very strange things with descriptor numbers. */ + last_avail_idx = vq->last_avail_idx; + if (unlikely(__get_user(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(__get_user(ring_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; + } + + 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 = __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 & 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)) { + vq_err(vq, "Failure detected " + "in indirect descriptor at idx %d\n", i); + return ret; + } + continue; + } + + ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr), + vhost32_to_cpu(vq, 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 & cpu_to_vhost16(vq, VRING_DESC_F_WRITE)) { + /* 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; + used = vq->used->ring + start; + if (count == 1) { + if (__put_user(heads[0].id, &used->id)) { + vq_err(vq, "Failed to write used id"); + return -EFAULT; + } + if (__put_user(heads[0].len, &used->len)) { + vq_err(vq, "Failed to write used len"); + return -EFAULT; + } + } else 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(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 (__get_user(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 (__get_user(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); + +/* 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 = __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 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); + +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"); -- cgit 1.2.3-korg