2723feaa8e
We need to log writes when updating used flags and avail event fields. Otherwise the guest may see a stale value after migration and miss notifying the host. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
1608 lines
41 KiB
C
1608 lines
41 KiB
C
/* Copyright (C) 2009 Red Hat, Inc.
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* Copyright (C) 2006 Rusty Russell IBM Corporation
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*
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* Author: Michael S. Tsirkin <mst@redhat.com>
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*
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* Inspiration, some code, and most witty comments come from
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* Documentation/virtual/lguest/lguest.c, by Rusty Russell
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*
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* This work is licensed under the terms of the GNU GPL, version 2.
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*
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* Generic code for virtio server in host kernel.
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*/
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#include <linux/eventfd.h>
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#include <linux/vhost.h>
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#include <linux/virtio_net.h>
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#include <linux/mm.h>
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#include <linux/mmu_context.h>
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#include <linux/miscdevice.h>
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#include <linux/mutex.h>
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#include <linux/rcupdate.h>
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#include <linux/poll.h>
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#include <linux/file.h>
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#include <linux/highmem.h>
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#include <linux/slab.h>
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#include <linux/kthread.h>
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#include <linux/cgroup.h>
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#include <linux/net.h>
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#include <linux/if_packet.h>
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#include <linux/if_arp.h>
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#include "vhost.h"
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enum {
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VHOST_MEMORY_MAX_NREGIONS = 64,
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VHOST_MEMORY_F_LOG = 0x1,
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};
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static unsigned vhost_zcopy_mask __read_mostly;
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#define vhost_used_event(vq) ((u16 __user *)&vq->avail->ring[vq->num])
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#define vhost_avail_event(vq) ((u16 __user *)&vq->used->ring[vq->num])
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static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
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poll_table *pt)
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{
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struct vhost_poll *poll;
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poll = container_of(pt, struct vhost_poll, table);
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poll->wqh = wqh;
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add_wait_queue(wqh, &poll->wait);
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}
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static int vhost_poll_wakeup(wait_queue_t *wait, unsigned mode, int sync,
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void *key)
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{
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struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait);
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if (!((unsigned long)key & poll->mask))
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return 0;
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vhost_poll_queue(poll);
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return 0;
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}
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static void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn)
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{
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INIT_LIST_HEAD(&work->node);
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work->fn = fn;
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init_waitqueue_head(&work->done);
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work->flushing = 0;
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work->queue_seq = work->done_seq = 0;
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}
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/* Init poll structure */
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void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
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unsigned long mask, struct vhost_dev *dev)
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{
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init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);
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init_poll_funcptr(&poll->table, vhost_poll_func);
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poll->mask = mask;
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poll->dev = dev;
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vhost_work_init(&poll->work, fn);
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}
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/* Start polling a file. We add ourselves to file's wait queue. The caller must
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* keep a reference to a file until after vhost_poll_stop is called. */
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void vhost_poll_start(struct vhost_poll *poll, struct file *file)
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{
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unsigned long mask;
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mask = file->f_op->poll(file, &poll->table);
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if (mask)
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vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask);
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}
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/* Stop polling a file. After this function returns, it becomes safe to drop the
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* file reference. You must also flush afterwards. */
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void vhost_poll_stop(struct vhost_poll *poll)
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{
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remove_wait_queue(poll->wqh, &poll->wait);
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}
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static bool vhost_work_seq_done(struct vhost_dev *dev, struct vhost_work *work,
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unsigned seq)
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{
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int left;
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spin_lock_irq(&dev->work_lock);
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left = seq - work->done_seq;
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spin_unlock_irq(&dev->work_lock);
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return left <= 0;
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}
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static void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work)
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{
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unsigned seq;
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int flushing;
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spin_lock_irq(&dev->work_lock);
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seq = work->queue_seq;
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work->flushing++;
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spin_unlock_irq(&dev->work_lock);
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wait_event(work->done, vhost_work_seq_done(dev, work, seq));
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spin_lock_irq(&dev->work_lock);
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flushing = --work->flushing;
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spin_unlock_irq(&dev->work_lock);
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BUG_ON(flushing < 0);
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}
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/* Flush any work that has been scheduled. When calling this, don't hold any
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* locks that are also used by the callback. */
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void vhost_poll_flush(struct vhost_poll *poll)
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{
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vhost_work_flush(poll->dev, &poll->work);
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}
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static inline void vhost_work_queue(struct vhost_dev *dev,
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struct vhost_work *work)
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{
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unsigned long flags;
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spin_lock_irqsave(&dev->work_lock, flags);
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if (list_empty(&work->node)) {
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list_add_tail(&work->node, &dev->work_list);
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work->queue_seq++;
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wake_up_process(dev->worker);
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}
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spin_unlock_irqrestore(&dev->work_lock, flags);
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}
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void vhost_poll_queue(struct vhost_poll *poll)
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{
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vhost_work_queue(poll->dev, &poll->work);
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}
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static void vhost_vq_reset(struct vhost_dev *dev,
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struct vhost_virtqueue *vq)
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{
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vq->num = 1;
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vq->desc = NULL;
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vq->avail = NULL;
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vq->used = NULL;
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vq->last_avail_idx = 0;
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vq->avail_idx = 0;
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vq->last_used_idx = 0;
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vq->signalled_used = 0;
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vq->signalled_used_valid = false;
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vq->used_flags = 0;
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vq->log_used = false;
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vq->log_addr = -1ull;
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vq->vhost_hlen = 0;
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vq->sock_hlen = 0;
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vq->private_data = NULL;
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vq->log_base = NULL;
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vq->error_ctx = NULL;
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vq->error = NULL;
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vq->kick = NULL;
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vq->call_ctx = NULL;
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vq->call = NULL;
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vq->log_ctx = NULL;
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vq->upend_idx = 0;
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vq->done_idx = 0;
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vq->ubufs = NULL;
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}
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static int vhost_worker(void *data)
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{
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struct vhost_dev *dev = data;
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struct vhost_work *work = NULL;
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unsigned uninitialized_var(seq);
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use_mm(dev->mm);
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for (;;) {
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/* mb paired w/ kthread_stop */
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set_current_state(TASK_INTERRUPTIBLE);
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spin_lock_irq(&dev->work_lock);
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if (work) {
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work->done_seq = seq;
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if (work->flushing)
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wake_up_all(&work->done);
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}
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if (kthread_should_stop()) {
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spin_unlock_irq(&dev->work_lock);
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__set_current_state(TASK_RUNNING);
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break;
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}
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if (!list_empty(&dev->work_list)) {
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work = list_first_entry(&dev->work_list,
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struct vhost_work, node);
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list_del_init(&work->node);
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seq = work->queue_seq;
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} else
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work = NULL;
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spin_unlock_irq(&dev->work_lock);
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if (work) {
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__set_current_state(TASK_RUNNING);
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work->fn(work);
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} else
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schedule();
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}
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unuse_mm(dev->mm);
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return 0;
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}
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static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq)
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{
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kfree(vq->indirect);
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vq->indirect = NULL;
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kfree(vq->log);
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vq->log = NULL;
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kfree(vq->heads);
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vq->heads = NULL;
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kfree(vq->ubuf_info);
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vq->ubuf_info = NULL;
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}
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void vhost_enable_zcopy(int vq)
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{
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vhost_zcopy_mask |= 0x1 << vq;
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}
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/* Helper to allocate iovec buffers for all vqs. */
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static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
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{
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int i;
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bool zcopy;
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for (i = 0; i < dev->nvqs; ++i) {
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dev->vqs[i].indirect = kmalloc(sizeof *dev->vqs[i].indirect *
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UIO_MAXIOV, GFP_KERNEL);
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dev->vqs[i].log = kmalloc(sizeof *dev->vqs[i].log * UIO_MAXIOV,
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GFP_KERNEL);
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dev->vqs[i].heads = kmalloc(sizeof *dev->vqs[i].heads *
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UIO_MAXIOV, GFP_KERNEL);
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zcopy = vhost_zcopy_mask & (0x1 << i);
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if (zcopy)
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dev->vqs[i].ubuf_info =
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kmalloc(sizeof *dev->vqs[i].ubuf_info *
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UIO_MAXIOV, GFP_KERNEL);
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if (!dev->vqs[i].indirect || !dev->vqs[i].log ||
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!dev->vqs[i].heads ||
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(zcopy && !dev->vqs[i].ubuf_info))
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goto err_nomem;
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}
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return 0;
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err_nomem:
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for (; i >= 0; --i)
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vhost_vq_free_iovecs(&dev->vqs[i]);
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return -ENOMEM;
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}
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static void vhost_dev_free_iovecs(struct vhost_dev *dev)
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{
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int i;
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for (i = 0; i < dev->nvqs; ++i)
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vhost_vq_free_iovecs(&dev->vqs[i]);
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}
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long vhost_dev_init(struct vhost_dev *dev,
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struct vhost_virtqueue *vqs, int nvqs)
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{
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int i;
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dev->vqs = vqs;
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dev->nvqs = nvqs;
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mutex_init(&dev->mutex);
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dev->log_ctx = NULL;
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dev->log_file = NULL;
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dev->memory = NULL;
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dev->mm = NULL;
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spin_lock_init(&dev->work_lock);
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INIT_LIST_HEAD(&dev->work_list);
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dev->worker = NULL;
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for (i = 0; i < dev->nvqs; ++i) {
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dev->vqs[i].log = NULL;
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dev->vqs[i].indirect = NULL;
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dev->vqs[i].heads = NULL;
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dev->vqs[i].ubuf_info = NULL;
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dev->vqs[i].dev = dev;
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mutex_init(&dev->vqs[i].mutex);
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vhost_vq_reset(dev, dev->vqs + i);
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if (dev->vqs[i].handle_kick)
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vhost_poll_init(&dev->vqs[i].poll,
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dev->vqs[i].handle_kick, POLLIN, dev);
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}
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return 0;
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}
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/* Caller should have device mutex */
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long vhost_dev_check_owner(struct vhost_dev *dev)
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{
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/* Are you the owner? If not, I don't think you mean to do that */
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return dev->mm == current->mm ? 0 : -EPERM;
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}
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struct vhost_attach_cgroups_struct {
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struct vhost_work work;
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struct task_struct *owner;
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int ret;
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};
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static void vhost_attach_cgroups_work(struct vhost_work *work)
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{
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struct vhost_attach_cgroups_struct *s;
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s = container_of(work, struct vhost_attach_cgroups_struct, work);
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s->ret = cgroup_attach_task_all(s->owner, current);
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}
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static int vhost_attach_cgroups(struct vhost_dev *dev)
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{
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struct vhost_attach_cgroups_struct attach;
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attach.owner = current;
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vhost_work_init(&attach.work, vhost_attach_cgroups_work);
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vhost_work_queue(dev, &attach.work);
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vhost_work_flush(dev, &attach.work);
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return attach.ret;
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}
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/* Caller should have device mutex */
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static long vhost_dev_set_owner(struct vhost_dev *dev)
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{
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struct task_struct *worker;
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int err;
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/* Is there an owner already? */
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if (dev->mm) {
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err = -EBUSY;
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goto err_mm;
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}
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/* No owner, become one */
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dev->mm = get_task_mm(current);
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worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
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if (IS_ERR(worker)) {
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err = PTR_ERR(worker);
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goto err_worker;
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}
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dev->worker = worker;
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wake_up_process(worker); /* avoid contributing to loadavg */
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err = vhost_attach_cgroups(dev);
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if (err)
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goto err_cgroup;
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err = vhost_dev_alloc_iovecs(dev);
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if (err)
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goto err_cgroup;
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return 0;
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err_cgroup:
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kthread_stop(worker);
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dev->worker = NULL;
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err_worker:
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if (dev->mm)
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mmput(dev->mm);
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dev->mm = NULL;
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err_mm:
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return err;
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}
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/* Caller should have device mutex */
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long vhost_dev_reset_owner(struct vhost_dev *dev)
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{
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struct vhost_memory *memory;
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/* Restore memory to default empty mapping. */
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memory = kmalloc(offsetof(struct vhost_memory, regions), GFP_KERNEL);
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if (!memory)
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return -ENOMEM;
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vhost_dev_cleanup(dev);
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memory->nregions = 0;
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RCU_INIT_POINTER(dev->memory, memory);
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return 0;
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}
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/* In case of DMA done not in order in lower device driver for some reason.
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* upend_idx is used to track end of used idx, done_idx is used to track head
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* of used idx. Once lower device DMA done contiguously, we will signal KVM
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* guest used idx.
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*/
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int vhost_zerocopy_signal_used(struct vhost_virtqueue *vq)
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{
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int i;
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int j = 0;
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for (i = vq->done_idx; i != vq->upend_idx; i = (i + 1) % UIO_MAXIOV) {
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if ((vq->heads[i].len == VHOST_DMA_DONE_LEN)) {
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vq->heads[i].len = VHOST_DMA_CLEAR_LEN;
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vhost_add_used_and_signal(vq->dev, vq,
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vq->heads[i].id, 0);
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++j;
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} else
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break;
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}
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if (j)
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vq->done_idx = i;
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return j;
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}
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/* Caller should have device mutex */
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void vhost_dev_cleanup(struct vhost_dev *dev)
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{
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int i;
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for (i = 0; i < dev->nvqs; ++i) {
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if (dev->vqs[i].kick && dev->vqs[i].handle_kick) {
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vhost_poll_stop(&dev->vqs[i].poll);
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vhost_poll_flush(&dev->vqs[i].poll);
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}
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/* Wait for all lower device DMAs done. */
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if (dev->vqs[i].ubufs)
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vhost_ubuf_put_and_wait(dev->vqs[i].ubufs);
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/* Signal guest as appropriate. */
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vhost_zerocopy_signal_used(&dev->vqs[i]);
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if (dev->vqs[i].error_ctx)
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eventfd_ctx_put(dev->vqs[i].error_ctx);
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if (dev->vqs[i].error)
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fput(dev->vqs[i].error);
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if (dev->vqs[i].kick)
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fput(dev->vqs[i].kick);
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if (dev->vqs[i].call_ctx)
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eventfd_ctx_put(dev->vqs[i].call_ctx);
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if (dev->vqs[i].call)
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fput(dev->vqs[i].call);
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vhost_vq_reset(dev, dev->vqs + i);
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}
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vhost_dev_free_iovecs(dev);
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if (dev->log_ctx)
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eventfd_ctx_put(dev->log_ctx);
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dev->log_ctx = NULL;
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if (dev->log_file)
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fput(dev->log_file);
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dev->log_file = NULL;
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/* No one will access memory at this point */
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kfree(rcu_dereference_protected(dev->memory,
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lockdep_is_held(&dev->mutex)));
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RCU_INIT_POINTER(dev->memory, NULL);
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WARN_ON(!list_empty(&dev->work_list));
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if (dev->worker) {
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kthread_stop(dev->worker);
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dev->worker = NULL;
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}
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if (dev->mm)
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mmput(dev->mm);
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dev->mm = NULL;
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}
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static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
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{
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u64 a = addr / VHOST_PAGE_SIZE / 8;
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/* Make sure 64 bit math will not overflow. */
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if (a > ULONG_MAX - (unsigned long)log_base ||
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a + (unsigned long)log_base > ULONG_MAX)
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return 0;
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return access_ok(VERIFY_WRITE, log_base + a,
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(sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
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}
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/* Caller should have vq mutex and device mutex. */
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static int vq_memory_access_ok(void __user *log_base, struct vhost_memory *mem,
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int log_all)
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{
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int i;
|
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|
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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, KM_USER0);
|
|
set_bit(bit, base);
|
|
kunmap_atomic(base, KM_USER0);
|
|
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);
|
|
kref_get(&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(void *arg)
|
|
{
|
|
struct ubuf_info *ubuf = arg;
|
|
struct vhost_ubuf_ref *ubufs = ubuf->arg;
|
|
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);
|
|
}
|