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/file.h>
  17 #include <linux/slab.h>
  18
  19 #include "test.h"
  20 #include "vhost.h"
  21
  22 /* Max number of bytes transferred before requeueing the job.
  23  * Using this limit prevents one virtqueue from starving others. */
  24 #define VHOST_TEST_WEIGHT 0x80000
  25
  26 enum {
  27         VHOST_TEST_VQ = 0,
  28         VHOST_TEST_VQ_MAX = 1,
  29 };
  30
  31 struct vhost_test {
  32         struct vhost_dev dev;
  33         struct vhost_virtqueue vqs[VHOST_TEST_VQ_MAX];
  34 };
  35
  36 /* Expects to be always run from workqueue - which acts as
  37  * read-size critical section for our kind of RCU. */
  38 static void handle_vq(struct vhost_test *n)
  39 {
  40         struct vhost_virtqueue *vq = &n->vqs[VHOST_TEST_VQ];
  41         unsigned out, in;
  42         int head;
  43         size_t len, total_len = 0;
  44         void *private;
  45
  46         mutex_lock(&vq->mutex);
  47         private = vq->private_data;
  48         if (!private) {
  49                 mutex_unlock(&vq->mutex);
  50                 return;
  51         }
  52
  53         vhost_disable_notify(&n->dev, vq);
  54
  55         for (;;) {
  56                 head = vhost_get_vq_desc(vq, vq->iov,
  57                                          ARRAY_SIZE(vq->iov),
  58                                          &out, &in,
  59                                          NULL, NULL);
  60                 /* On error, stop handling until the next kick. */
  61                 if (unlikely(head < 0))
  62                         break;
  63                 /* Nothing new?  Wait for eventfd to tell us they refilled. */
  64                 if (head == vq->num) {
  65                         if (unlikely(vhost_enable_notify(&n->dev, vq))) {
  66                                 vhost_disable_notify(&n->dev, vq);
  67                                 continue;
  68                         }
  69                         break;
  70                 }
  71                 if (in) {
  72                         vq_err(vq, "Unexpected descriptor format for TX: "
  73                                "out %d, int %d\n", out, in);
  74                         break;
  75                 }
  76                 len = iov_length(vq->iov, out);
  77                 /* Sanity check */
  78                 if (!len) {
  79                         vq_err(vq, "Unexpected 0 len for TX\n");
  80                         break;
  81                 }
  82                 vhost_add_used_and_signal(&n->dev, vq, head, 0);
  83                 total_len += len;
  84                 if (unlikely(total_len >= VHOST_TEST_WEIGHT)) {
  85                         vhost_poll_queue(&vq->poll);
  86                         break;
  87                 }
  88         }
  89
  90         mutex_unlock(&vq->mutex);
  91 }
  92
  93 static void handle_vq_kick(struct vhost_work *work)
  94 {
  95         struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
  96                                                   poll.work);
  97         struct vhost_test *n = container_of(vq->dev, struct vhost_test, dev);
  98
  99         handle_vq(n);
 100 }
 101
 102 static int vhost_test_open(struct inode *inode, struct file *f)
 103 {
 104         struct vhost_test *n = kmalloc(sizeof *n, GFP_KERNEL);
 105         struct vhost_dev *dev;
 106         struct vhost_virtqueue **vqs;
 107
 108         if (!n)
 109                 return -ENOMEM;
 110         vqs = kmalloc(VHOST_TEST_VQ_MAX * sizeof(*vqs), GFP_KERNEL);
 111         if (!vqs) {
 112                 kfree(n);
 113                 return -ENOMEM;
 114         }
 115
 116         dev = &n->dev;
 117         vqs[VHOST_TEST_VQ] = &n->vqs[VHOST_TEST_VQ];
 118         n->vqs[VHOST_TEST_VQ].handle_kick = handle_vq_kick;
 119         vhost_dev_init(dev, vqs, VHOST_TEST_VQ_MAX);
 120
 121         f->private_data = n;
 122
 123         return 0;
 124 }
 125
 126 static void *vhost_test_stop_vq(struct vhost_test *n,
 127                                 struct vhost_virtqueue *vq)
 128 {
 129         void *private;
 130
 131         mutex_lock(&vq->mutex);
 132         private = vq->private_data;
 133         vq->private_data = NULL;
 134         mutex_unlock(&vq->mutex);
 135         return private;
 136 }
 137
 138 static void vhost_test_stop(struct vhost_test *n, void **privatep)
 139 {
 140         *privatep = vhost_test_stop_vq(n, n->vqs + VHOST_TEST_VQ);
 141 }
 142
 143 static void vhost_test_flush_vq(struct vhost_test *n, int index)
 144 {
 145         vhost_poll_flush(&n->vqs[index].poll);
 146 }
 147
 148 static void vhost_test_flush(struct vhost_test *n)
 149 {
 150         vhost_test_flush_vq(n, VHOST_TEST_VQ);
 151 }
 152
 153 static int vhost_test_release(struct inode *inode, struct file *f)
 154 {
 155         struct vhost_test *n = f->private_data;
 156         void  *private;
 157
 158         vhost_test_stop(n, &private);
 159         vhost_test_flush(n);
 160         vhost_dev_cleanup(&n->dev, false);
 161         /* We do an extra flush before freeing memory,
 162          * since jobs can re-queue themselves. */
 163         vhost_test_flush(n);
 164         kfree(n);
 165         return 0;
 166 }
 167
 168 static long vhost_test_run(struct vhost_test *n, int test)
 169 {
 170         void *priv, *oldpriv;
 171         struct vhost_virtqueue *vq;
 172         int r, index;
 173
 174         if (test < 0 || test > 1)
 175                 return -EINVAL;
 176
 177         mutex_lock(&n->dev.mutex);
 178         r = vhost_dev_check_owner(&n->dev);
 179         if (r)
 180                 goto err;
 181
 182         for (index = 0; index < n->dev.nvqs; ++index) {
 183                 /* Verify that ring has been setup correctly. */
 184                 if (!vhost_vq_access_ok(&n->vqs[index])) {
 185                         r = -EFAULT;
 186                         goto err;
 187                 }
 188         }
 189
 190         for (index = 0; index < n->dev.nvqs; ++index) {
 191                 vq = n->vqs + index;
 192                 mutex_lock(&vq->mutex);
 193                 priv = test ? n : NULL;
 194
 195                 /* start polling new socket */
 196                 oldpriv = vq->private_data;
 197                 vq->private_data = priv;
 198
 199                 r = vhost_init_used(&n->vqs[index]);
 200
 201                 mutex_unlock(&vq->mutex);
 202
 203                 if (r)
 204                         goto err;
 205
 206                 if (oldpriv) {
 207                         vhost_test_flush_vq(n, index);
 208                 }
 209         }
 210
 211         mutex_unlock(&n->dev.mutex);
 212         return 0;
 213
 214 err:
 215         mutex_unlock(&n->dev.mutex);
 216         return r;
 217 }
 218
 219 static long vhost_test_reset_owner(struct vhost_test *n)
 220 {
 221         void *priv = NULL;
 222         long err;
 223         struct vhost_memory *memory;
 224
 225         mutex_lock(&n->dev.mutex);
 226         err = vhost_dev_check_owner(&n->dev);
 227         if (err)
 228                 goto done;
 229         memory = vhost_dev_reset_owner_prepare();
 230         if (!memory) {
 231                 err = -ENOMEM;
 232                 goto done;
 233         }
 234         vhost_test_stop(n, &priv);
 235         vhost_test_flush(n);
 236         vhost_dev_reset_owner(&n->dev, memory);
 237 done:
 238         mutex_unlock(&n->dev.mutex);
 239         return err;
 240 }
 241
 242 static int vhost_test_set_features(struct vhost_test *n, u64 features)
 243 {
 244         struct vhost_virtqueue *vq;
 245
 246         mutex_lock(&n->dev.mutex);
 247         if ((features & (1 << VHOST_F_LOG_ALL)) &&
 248             !vhost_log_access_ok(&n->dev)) {
 249                 mutex_unlock(&n->dev.mutex);
 250                 return -EFAULT;
 251         }
 252         vq = &n->vqs[VHOST_TEST_VQ];
 253         mutex_lock(&vq->mutex);
 254         vq->acked_features = features;
 255         mutex_unlock(&vq->mutex);
 256         mutex_unlock(&n->dev.mutex);
 257         return 0;
 258 }
 259
 260 static long vhost_test_ioctl(struct file *f, unsigned int ioctl,
 261                              unsigned long arg)
 262 {
 263         struct vhost_test *n = f->private_data;
 264         void __user *argp = (void __user *)arg;
 265         u64 __user *featurep = argp;
 266         int test;
 267         u64 features;
 268         int r;
 269         switch (ioctl) {
 270         case VHOST_TEST_RUN:
 271                 if (copy_from_user(&test, argp, sizeof test))
 272                         return -EFAULT;
 273                 return vhost_test_run(n, test);
 274         case VHOST_GET_FEATURES:
 275                 features = VHOST_FEATURES;
 276                 if (copy_to_user(featurep, &features, sizeof features))
 277                         return -EFAULT;
 278                 return 0;
 279         case VHOST_SET_FEATURES:
 280                 if (copy_from_user(&features, featurep, sizeof features))
 281                         return -EFAULT;
 282                 if (features & ~VHOST_FEATURES)
 283                         return -EOPNOTSUPP;
 284                 return vhost_test_set_features(n, features);
 285         case VHOST_RESET_OWNER:
 286                 return vhost_test_reset_owner(n);
 287         default:
 288                 mutex_lock(&n->dev.mutex);
 289                 r = vhost_dev_ioctl(&n->dev, ioctl, argp);
 290                 if (r == -ENOIOCTLCMD)
 291                         r = vhost_vring_ioctl(&n->dev, ioctl, argp);
 292                 vhost_test_flush(n);
 293                 mutex_unlock(&n->dev.mutex);
 294                 return r;
 295         }
 296 }
 297
 298 #ifdef CONFIG_COMPAT
 299 static long vhost_test_compat_ioctl(struct file *f, unsigned int ioctl,
 300                                    unsigned long arg)
 301 {
 302         return vhost_test_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
 303 }
 304 #endif
 305
 306 static const struct file_operations vhost_test_fops = {
 307         .owner          = THIS_MODULE,
 308         .release        = vhost_test_release,
 309         .unlocked_ioctl = vhost_test_ioctl,
 310 #ifdef CONFIG_COMPAT
 311         .compat_ioctl   = vhost_test_compat_ioctl,
 312 #endif
 313         .open           = vhost_test_open,
 314         .llseek         = noop_llseek,
 315 };
 316
 317 static struct miscdevice vhost_test_misc = {
 318         MISC_DYNAMIC_MINOR,
 319         "vhost-test",
 320         &vhost_test_fops,
 321 };
 322
 323 static int vhost_test_init(void)
 324 {
 325         return misc_register(&vhost_test_misc);
 326 }
 327 module_init(vhost_test_init);
 328
 329 static void vhost_test_exit(void)
 330 {
 331         misc_deregister(&vhost_test_misc);
 332 }
 333 module_exit(vhost_test_exit);
 334
 335 MODULE_VERSION("0.0.1");
 336 MODULE_LICENSE("GPL v2");
 337 MODULE_AUTHOR("Michael S. Tsirkin");
 338 MODULE_DESCRIPTION("Host kernel side for virtio simulator");