drivers/vhost/test.c

   1 /* Copyright (C) 2009 Red Hat, Inc.
   2  * Author: Michael S. Tsirkin <mst@redhat.com>
   3  *
   4  * This work is licensed under the terms of the GNU GPL, version 2.
   5  *
   6  * test virtio server in host kernel.
   7  */
   8
   9 #include <linux/compat.h>
  10 #include <linux/eventfd.h>
  11 #include <linux/vhost.h>
  12 #include <linux/miscdevice.h>
  13 #include <linux/module.h>
  14 #include <linux/mutex.h>
  15 #include <linux/workqueue.h>
  16 #include <linux/rcupdate.h>
  17 #include <linux/file.h>
  18 #include <linux/slab.h>
  19
  20 #include "test.h"
  21 #include "vhost.c"
  22
  23 /* Max number of bytes transferred before requeueing the job.
  24  * Using this limit prevents one virtqueue from starving others. */
  25 #define VHOST_TEST_WEIGHT 0x80000
  26
  27 enum {
  28         VHOST_TEST_VQ = 0,
  29         VHOST_TEST_VQ_MAX = 1,
  30 };
  31
  32 struct vhost_test {
  33         struct vhost_dev dev;
  34         struct vhost_virtqueue vqs[VHOST_TEST_VQ_MAX];
  35 };
  36
  37 /* Expects to be always run from workqueue - which acts as
  38  * read-size critical section for our kind of RCU. */
  39 static void handle_vq(struct vhost_test *n)
  40 {
  41         struct vhost_virtqueue *vq = &n->dev.vqs[VHOST_TEST_VQ];
  42         unsigned out, in;
  43         int head;
  44         size_t len, total_len = 0;
  45         void *private;
  46
  47         private = rcu_dereference_check(vq->private_data, 1);
  48         if (!private)
  49                 return;
  50
  51         mutex_lock(&vq->mutex);
  52         vhost_disable_notify(&n->dev, vq);
  53
  54         for (;;) {
  55                 head = vhost_get_vq_desc(&n->dev, vq, vq->iov,
  56                                          ARRAY_SIZE(vq->iov),
  57                                          &out, &in,
  58                                          NULL, NULL);
  59                 /* On error, stop handling until the next kick. */
  60                 if (unlikely(head < 0))
  61                         break;
  62                 /* Nothing new?  Wait for eventfd to tell us they refilled. */
  63                 if (head == vq->num) {
  64                         if (unlikely(vhost_enable_notify(&n->dev, vq))) {
  65                                 vhost_disable_notify(&n->dev, vq);
  66                                 continue;
  67                         }
  68                         break;
  69                 }
  70                 if (in) {
  71                         vq_err(vq, "Unexpected descriptor format for TX: "
  72                                "out %d, int %d\n", out, in);
  73                         break;
  74                 }
  75                 len = iov_length(vq->iov, out);
  76                 /* Sanity check */
  77                 if (!len) {
  78                         vq_err(vq, "Unexpected 0 len for TX\n");
  79                         break;
  80                 }
  81                 vhost_add_used_and_signal(&n->dev, vq, head, 0);
  82                 total_len += len;
  83                 if (unlikely(total_len >= VHOST_TEST_WEIGHT)) {
  84                         vhost_poll_queue(&vq->poll);
  85                         break;
  86                 }
  87         }
  88
  89         mutex_unlock(&vq->mutex);
  90 }
  91
  92 static void handle_vq_kick(struct vhost_work *work)
  93 {
  94         struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
  95                                                   poll.work);
  96         struct vhost_test *n = container_of(vq->dev, struct vhost_test, dev);
  97
  98         handle_vq(n);
  99 }
 100
 101 static int vhost_test_open(struct inode *inode, struct file *f)
 102 {
 103         struct vhost_test *n = kmalloc(sizeof *n, GFP_KERNEL);
 104         struct vhost_dev *dev;
 105         int r;
 106
 107         if (!n)
 108                 return -ENOMEM;
 109
 110         dev = &n->dev;
 111         n->vqs[VHOST_TEST_VQ].handle_kick = handle_vq_kick;
 112         r = vhost_dev_init(dev, n->vqs, VHOST_TEST_VQ_MAX);
 113         if (r < 0) {
 114                 kfree(n);
 115                 return r;
 116         }
 117
 118         f->private_data = n;
 119
 120         return 0;
 121 }
 122
 123 static void *vhost_test_stop_vq(struct vhost_test *n,
 124                                 struct vhost_virtqueue *vq)
 125 {
 126         void *private;
 127
 128         mutex_lock(&vq->mutex);
 129         private = rcu_dereference_protected(vq->private_data,
 130                                          lockdep_is_held(&vq->mutex));
 131         rcu_assign_pointer(vq->private_data, NULL);
 132         mutex_unlock(&vq->mutex);
 133         return private;
 134 }
 135
 136 static void vhost_test_stop(struct vhost_test *n, void **privatep)
 137 {
 138         *privatep = vhost_test_stop_vq(n, n->vqs + VHOST_TEST_VQ);
 139 }
 140
 141 static void vhost_test_flush_vq(struct vhost_test *n, int index)
 142 {
 143         vhost_poll_flush(&n->dev.vqs[index].poll);
 144 }
 145
 146 static void vhost_test_flush(struct vhost_test *n)
 147 {
 148         vhost_test_flush_vq(n, VHOST_TEST_VQ);
 149 }
 150
 151 static int vhost_test_release(struct inode *inode, struct file *f)
 152 {
 153         struct vhost_test *n = f->private_data;
 154         void  *private;
 155
 156         vhost_test_stop(n, &private);
 157         vhost_test_flush(n);
 158         vhost_dev_cleanup(&n->dev);
 159         /* We do an extra flush before freeing memory,
 160          * since jobs can re-queue themselves. */
 161         vhost_test_flush(n);
 162         kfree(n);
 163         return 0;
 164 }
 165
 166 static long vhost_test_run(struct vhost_test *n, int test)
 167 {
 168         void *priv, *oldpriv;
 169         struct vhost_virtqueue *vq;
 170         int r, index;
 171
 172         if (test < 0 || test > 1)
 173                 return -EINVAL;
 174
 175         mutex_lock(&n->dev.mutex);
 176         r = vhost_dev_check_owner(&n->dev);
 177         if (r)
 178                 goto err;
 179
 180         for (index = 0; index < n->dev.nvqs; ++index) {
 181                 /* Verify that ring has been setup correctly. */
 182                 if (!vhost_vq_access_ok(&n->vqs[index])) {
 183                         r = -EFAULT;
 184                         goto err;
 185                 }
 186         }
 187
 188         for (index = 0; index < n->dev.nvqs; ++index) {
 189                 vq = n->vqs + index;
 190                 mutex_lock(&vq->mutex);
 191                 priv = test ? n : NULL;
 192
 193                 /* start polling new socket */
 194                 oldpriv = rcu_dereference_protected(vq->private_data,
 195                                                     lockdep_is_held(&vq->mutex));
 196                 rcu_assign_pointer(vq->private_data, priv);
 197
 198                 mutex_unlock(&vq->mutex);
 199
 200                 if (oldpriv) {
 201                         vhost_test_flush_vq(n, index);
 202                 }
 203         }
 204
 205         mutex_unlock(&n->dev.mutex);
 206         return 0;
 207
 208 err:
 209         mutex_unlock(&n->dev.mutex);
 210         return r;
 211 }
 212
 213 static long vhost_test_reset_owner(struct vhost_test *n)
 214 {
 215         void *priv = NULL;
 216         long err;
 217         mutex_lock(&n->dev.mutex);
 218         err = vhost_dev_check_owner(&n->dev);
 219         if (err)
 220                 goto done;
 221         vhost_test_stop(n, &priv);
 222         vhost_test_flush(n);
 223         err = vhost_dev_reset_owner(&n->dev);
 224 done:
 225         mutex_unlock(&n->dev.mutex);
 226         return err;
 227 }
 228
 229 static int vhost_test_set_features(struct vhost_test *n, u64 features)
 230 {
 231         mutex_lock(&n->dev.mutex);
 232         if ((features & (1 << VHOST_F_LOG_ALL)) &&
 233             !vhost_log_access_ok(&n->dev)) {
 234                 mutex_unlock(&n->dev.mutex);
 235                 return -EFAULT;
 236         }
 237         n->dev.acked_features = features;
 238         smp_wmb();
 239         vhost_test_flush(n);
 240         mutex_unlock(&n->dev.mutex);
 241         return 0;
 242 }
 243
 244 static long vhost_test_ioctl(struct file *f, unsigned int ioctl,
 245                              unsigned long arg)
 246 {
 247         struct vhost_test *n = f->private_data;
 248         void __user *argp = (void __user *)arg;
 249         u64 __user *featurep = argp;
 250         int test;
 251         u64 features;
 252         int r;
 253         switch (ioctl) {
 254         case VHOST_TEST_RUN:
 255                 if (copy_from_user(&test, argp, sizeof test))
 256                         return -EFAULT;
 257                 return vhost_test_run(n, test);
 258         case VHOST_GET_FEATURES:
 259                 features = VHOST_FEATURES;
 260                 if (copy_to_user(featurep, &features, sizeof features))
 261                         return -EFAULT;
 262                 return 0;
 263         case VHOST_SET_FEATURES:
 264                 if (copy_from_user(&features, featurep, sizeof features))
 265                         return -EFAULT;
 266                 if (features & ~VHOST_FEATURES)
 267                         return -EOPNOTSUPP;
 268                 return vhost_test_set_features(n, features);
 269         case VHOST_RESET_OWNER:
 270                 return vhost_test_reset_owner(n);
 271         default:
 272                 mutex_lock(&n->dev.mutex);
 273                 r = vhost_dev_ioctl(&n->dev, ioctl, arg);
 274                 vhost_test_flush(n);
 275                 mutex_unlock(&n->dev.mutex);
 276                 return r;
 277         }
 278 }
 279
 280 #ifdef CONFIG_COMPAT
 281 static long vhost_test_compat_ioctl(struct file *f, unsigned int ioctl,
 282                                    unsigned long arg)
 283 {
 284         return vhost_test_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
 285 }
 286 #endif
 287
 288 static const struct file_operations vhost_test_fops = {
 289         .owner          = THIS_MODULE,
 290         .release        = vhost_test_release,
 291         .unlocked_ioctl = vhost_test_ioctl,
 292 #ifdef CONFIG_COMPAT
 293         .compat_ioctl   = vhost_test_compat_ioctl,
 294 #endif
 295         .open           = vhost_test_open,
 296         .llseek         = noop_llseek,
 297 };
 298
 299 static struct miscdevice vhost_test_misc = {
 300         MISC_DYNAMIC_MINOR,
 301         "vhost-test",
 302         &vhost_test_fops,
 303 };
 304
 305 static int vhost_test_init(void)
 306 {
 307         return misc_register(&vhost_test_misc);
 308 }
 309 module_init(vhost_test_init);
 310
 311 static void vhost_test_exit(void)
 312 {
 313         misc_deregister(&vhost_test_misc);
 314 }
 315 module_exit(vhost_test_exit);
 316
 317 MODULE_VERSION("0.0.1");
 318 MODULE_LICENSE("GPL v2");
 319 MODULE_AUTHOR("Michael S. Tsirkin");
 320 MODULE_DESCRIPTION("Host kernel side for virtio simulator");