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/* Copyright (C) 2009 Red Hat, Inc.
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* Author: Michael S. Tsirkin <mst@redhat.com>
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* This work is licensed under the terms of the GNU GPL, version 2.
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* test virtio server in host kernel.
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#include <linux/compat.h>
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#include <linux/eventfd.h>
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#include <linux/vhost.h>
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#include <linux/miscdevice.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/workqueue.h>
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#include <linux/rcupdate.h>
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#include <linux/file.h>
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#include <linux/slab.h>
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/* Max number of bytes transferred before requeueing the job.
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* Using this limit prevents one virtqueue from starving others. */
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#define VHOST_TEST_WEIGHT 0x80000
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VHOST_TEST_VQ_MAX = 1,
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struct vhost_virtqueue vqs[VHOST_TEST_VQ_MAX];
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/* Expects to be always run from workqueue - which acts as
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* read-size critical section for our kind of RCU. */
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static void handle_vq(struct vhost_test *n)
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struct vhost_virtqueue *vq = &n->dev.vqs[VHOST_TEST_VQ];
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size_t len, total_len = 0;
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private = rcu_dereference_check(vq->private_data, 1);
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mutex_lock(&vq->mutex);
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vhost_disable_notify(&n->dev, vq);
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head = vhost_get_vq_desc(&n->dev, vq, vq->iov,
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/* On error, stop handling until the next kick. */
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if (unlikely(head < 0))
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/* Nothing new? Wait for eventfd to tell us they refilled. */
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if (head == vq->num) {
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if (unlikely(vhost_enable_notify(&n->dev, vq))) {
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vhost_disable_notify(&n->dev, vq);
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vq_err(vq, "Unexpected descriptor format for TX: "
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"out %d, int %d\n", out, in);
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len = iov_length(vq->iov, out);
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vq_err(vq, "Unexpected 0 len for TX\n");
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vhost_add_used_and_signal(&n->dev, vq, head, 0);
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if (unlikely(total_len >= VHOST_TEST_WEIGHT)) {
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vhost_poll_queue(&vq->poll);
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mutex_unlock(&vq->mutex);
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static void handle_vq_kick(struct vhost_work *work)
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struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
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struct vhost_test *n = container_of(vq->dev, struct vhost_test, dev);
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static int vhost_test_open(struct inode *inode, struct file *f)
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struct vhost_test *n = kmalloc(sizeof *n, GFP_KERNEL);
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struct vhost_dev *dev;
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n->vqs[VHOST_TEST_VQ].handle_kick = handle_vq_kick;
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r = vhost_dev_init(dev, n->vqs, VHOST_TEST_VQ_MAX);
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static void *vhost_test_stop_vq(struct vhost_test *n,
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struct vhost_virtqueue *vq)
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mutex_lock(&vq->mutex);
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private = rcu_dereference_protected(vq->private_data,
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lockdep_is_held(&vq->mutex));
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rcu_assign_pointer(vq->private_data, NULL);
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mutex_unlock(&vq->mutex);
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static void vhost_test_stop(struct vhost_test *n, void **privatep)
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*privatep = vhost_test_stop_vq(n, n->vqs + VHOST_TEST_VQ);
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static void vhost_test_flush_vq(struct vhost_test *n, int index)
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vhost_poll_flush(&n->dev.vqs[index].poll);
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static void vhost_test_flush(struct vhost_test *n)
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vhost_test_flush_vq(n, VHOST_TEST_VQ);
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static int vhost_test_release(struct inode *inode, struct file *f)
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struct vhost_test *n = f->private_data;
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vhost_test_stop(n, &private);
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vhost_dev_cleanup(&n->dev);
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/* We do an extra flush before freeing memory,
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* since jobs can re-queue themselves. */
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static long vhost_test_run(struct vhost_test *n, int test)
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void *priv, *oldpriv;
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struct vhost_virtqueue *vq;
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if (test < 0 || test > 1)
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mutex_lock(&n->dev.mutex);
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r = vhost_dev_check_owner(&n->dev);
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for (index = 0; index < n->dev.nvqs; ++index) {
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/* Verify that ring has been setup correctly. */
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if (!vhost_vq_access_ok(&n->vqs[index])) {
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for (index = 0; index < n->dev.nvqs; ++index) {
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mutex_lock(&vq->mutex);
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priv = test ? n : NULL;
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/* start polling new socket */
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oldpriv = rcu_dereference_protected(vq->private_data,
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lockdep_is_held(&vq->mutex));
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rcu_assign_pointer(vq->private_data, priv);
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r = vhost_init_used(&n->vqs[index]);
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mutex_unlock(&vq->mutex);
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vhost_test_flush_vq(n, index);
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mutex_unlock(&n->dev.mutex);
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mutex_unlock(&n->dev.mutex);
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static long vhost_test_reset_owner(struct vhost_test *n)
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mutex_lock(&n->dev.mutex);
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err = vhost_dev_check_owner(&n->dev);
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vhost_test_stop(n, &priv);
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err = vhost_dev_reset_owner(&n->dev);
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mutex_unlock(&n->dev.mutex);
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static int vhost_test_set_features(struct vhost_test *n, u64 features)
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mutex_lock(&n->dev.mutex);
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if ((features & (1 << VHOST_F_LOG_ALL)) &&
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!vhost_log_access_ok(&n->dev)) {
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mutex_unlock(&n->dev.mutex);
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n->dev.acked_features = features;
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mutex_unlock(&n->dev.mutex);
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static long vhost_test_ioctl(struct file *f, unsigned int ioctl,
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struct vhost_test *n = f->private_data;
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void __user *argp = (void __user *)arg;
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u64 __user *featurep = argp;
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if (copy_from_user(&test, argp, sizeof test))
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return vhost_test_run(n, test);
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case VHOST_GET_FEATURES:
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features = VHOST_FEATURES;
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if (copy_to_user(featurep, &features, sizeof features))
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case VHOST_SET_FEATURES:
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if (copy_from_user(&features, featurep, sizeof features))
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if (features & ~VHOST_FEATURES)
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return vhost_test_set_features(n, features);
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case VHOST_RESET_OWNER:
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return vhost_test_reset_owner(n);
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mutex_lock(&n->dev.mutex);
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r = vhost_dev_ioctl(&n->dev, ioctl, arg);
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mutex_unlock(&n->dev.mutex);
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static long vhost_test_compat_ioctl(struct file *f, unsigned int ioctl,
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return vhost_test_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
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static const struct file_operations vhost_test_fops = {
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.owner = THIS_MODULE,
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.release = vhost_test_release,
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.unlocked_ioctl = vhost_test_ioctl,
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.compat_ioctl = vhost_test_compat_ioctl,
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.open = vhost_test_open,
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.llseek = noop_llseek,
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static struct miscdevice vhost_test_misc = {
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static int vhost_test_init(void)
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return misc_register(&vhost_test_misc);
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module_init(vhost_test_init);
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static void vhost_test_exit(void)
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misc_deregister(&vhost_test_misc);
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module_exit(vhost_test_exit);
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MODULE_VERSION("0.0.1");
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MODULE_LICENSE("GPL v2");
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MODULE_AUTHOR("Michael S. Tsirkin");
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MODULE_DESCRIPTION("Host kernel side for virtio simulator");