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.h"
  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->vqs[VHOST_TEST_VQ];
  42         unsigned out, in;
  43         int head;
  44         size_t len, total_len = 0;
  45         void *private;
  46
  47         mutex_lock(&vq->mutex);
  48         private = vq->private_data;
  49         if (!private) {
  50                 mutex_unlock(&vq->mutex);
  51                 return;
  52         }
  53
  54         vhost_disable_notify(&n->dev, vq);
  55
  56         for (;;) {
  57                 head = vhost_get_vq_desc(&n->dev, vq, vq->iov,
  58                                          ARRAY_SIZE(vq->iov),
  59                                          &out, &in,
  60                                          NULL, NULL);
  61                 /* On error, stop handling until the next kick. */
  62                 if (unlikely(head < 0))
  63                         break;
  64                 /* Nothing new?  Wait for eventfd to tell us they refilled. */
  65                 if (head == vq->num) {
  66                         if (unlikely(vhost_enable_notify(&n->dev, vq))) {
  67                                 vhost_disable_notify(&n->dev, vq);
  68                                 continue;
  69                         }
  70                         break;
  71                 }
  72                 if (in) {
  73                         vq_err(vq, "Unexpected descriptor format for TX: "
  74                                "out %d, int %d\n", out, in);
  75                         break;
  76                 }
  77                 len = iov_length(vq->iov, out);
  78                 /* Sanity check */
  79                 if (!len) {
  80                         vq_err(vq, "Unexpected 0 len for TX\n");
  81                         break;
  82                 }
  83                 vhost_add_used_and_signal(&n->dev, vq, head, 0);
  84                 total_len += len;
  85                 if (unlikely(total_len >= VHOST_TEST_WEIGHT)) {
  86                         vhost_poll_queue(&vq->poll);
  87                         break;
  88                 }
  89         }
  90
  91         mutex_unlock(&vq->mutex);
  92 }
  93
  94 static void handle_vq_kick(struct vhost_work *work)
  95 {
  96         struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
  97                                                   poll.work);
  98         struct vhost_test *n = container_of(vq->dev, struct vhost_test, dev);
  99
 100         handle_vq(n);
 101 }
 102
 103 static int vhost_test_open(struct inode *inode, struct file *f)
 104 {
 105         struct vhost_test *n = kmalloc(sizeof *n, GFP_KERNEL);
 106         struct vhost_dev *dev;
 107         struct vhost_virtqueue **vqs;
 108         int r;
 109
 110         if (!n)
 111                 return -ENOMEM;
 112         vqs = kmalloc(VHOST_TEST_VQ_MAX * sizeof(*vqs), GFP_KERNEL);
 113         if (!vqs) {
 114                 kfree(n);
 115                 return -ENOMEM;
 116         }
 117
 118         dev = &n->dev;
 119         vqs[VHOST_TEST_VQ] = &n->vqs[VHOST_TEST_VQ];
 120         n->vqs[VHOST_TEST_VQ].handle_kick = handle_vq_kick;
 121         r = vhost_dev_init(dev, vqs, VHOST_TEST_VQ_MAX);
 122         if (r < 0) {
 123                 kfree(vqs);
 124                 kfree(n);
 125                 return r;
 126         }
 127
 128         f->private_data = n;
 129
 130         return 0;
 131 }
 132
 133 static void *vhost_test_stop_vq(struct vhost_test *n,
 134                                 struct vhost_virtqueue *vq)
 135 {
 136         void *private;
 137
 138         mutex_lock(&vq->mutex);
 139         private = vq->private_data;
 140         vq->private_data = NULL;
 141         mutex_unlock(&vq->mutex);
 142         return private;
 143 }
 144
 145 static void vhost_test_stop(struct vhost_test *n, void **privatep)
 146 {
 147         *privatep = vhost_test_stop_vq(n, n->vqs + VHOST_TEST_VQ);
 148 }
 149
 150 static void vhost_test_flush_vq(struct vhost_test *n, int index)
 151 {
 152         vhost_poll_flush(&n->vqs[index].poll);
 153 }
 154
 155 static void vhost_test_flush(struct vhost_test *n)
 156 {
 157         vhost_test_flush_vq(n, VHOST_TEST_VQ);
 158 }
 159
 160 static int vhost_test_release(struct inode *inode, struct file *f)
 161 {
 162         struct vhost_test *n = f->private_data;
 163         void  *private;
 164
 165         vhost_test_stop(n, &private);
 166         vhost_test_flush(n);
 167         vhost_dev_cleanup(&n->dev, false);
 168         /* We do an extra flush before freeing memory,
 169          * since jobs can re-queue themselves. */
 170         vhost_test_flush(n);
 171         kfree(n);
 172         return 0;
 173 }
 174
 175 static long vhost_test_run(struct vhost_test *n, int test)
 176 {
 177         void *priv, *oldpriv;
 178         struct vhost_virtqueue *vq;
 179         int r, index;
 180
 181         if (test < 0 || test > 1)
 182                 return -EINVAL;
 183
 184         mutex_lock(&n->dev.mutex);
 185         r = vhost_dev_check_owner(&n->dev);
 186         if (r)
 187                 goto err;
 188
 189         for (index = 0; index < n->dev.nvqs; ++index) {
 190                 /* Verify that ring has been setup correctly. */
 191                 if (!vhost_vq_access_ok(&n->vqs[index])) {
 192                         r = -EFAULT;
 193                         goto err;
 194                 }
 195         }
 196
 197         for (index = 0; index < n->dev.nvqs; ++index) {
 198                 vq = n->vqs + index;
 199                 mutex_lock(&vq->mutex);
 200                 priv = test ? n : NULL;
 201
 202                 /* start polling new socket */
 203                 oldpriv = rcu_dereference_protected(vq->private_data,
 204                                                     lockdep_is_held(&vq->mutex));
 205                 rcu_assign_pointer(vq->private_data, priv);
 206
 207                 r = vhost_init_used(&n->vqs[index]);
 208
 209                 mutex_unlock(&vq->mutex);
 210
 211                 if (r)
 212                         goto err;
 213
 214                 if (oldpriv) {
 215                         vhost_test_flush_vq(n, index);
 216                 }
 217         }
 218
 219         mutex_unlock(&n->dev.mutex);
 220         return 0;
 221
 222 err:
 223         mutex_unlock(&n->dev.mutex);
 224         return r;
 225 }
 226
 227 static long vhost_test_reset_owner(struct vhost_test *n)
 228 {
 229         void *priv = NULL;
 230         long err;
 231         struct vhost_memory *memory;
 232
 233         mutex_lock(&n->dev.mutex);
 234         err = vhost_dev_check_owner(&n->dev);
 235         if (err)
 236                 goto done;
 237         memory = vhost_dev_reset_owner_prepare();
 238         if (!memory) {
 239                 err = -ENOMEM;
 240                 goto done;
 241         }
 242         vhost_test_stop(n, &priv);
 243         vhost_test_flush(n);
 244         vhost_dev_reset_owner(&n->dev, memory);
 245 done:
 246         mutex_unlock(&n->dev.mutex);
 247         return err;
 248 }
 249
 250 static int vhost_test_set_features(struct vhost_test *n, u64 features)
 251 {
 252         mutex_lock(&n->dev.mutex);
 253         if ((features & (1 << VHOST_F_LOG_ALL)) &&
 254             !vhost_log_access_ok(&n->dev)) {
 255                 mutex_unlock(&n->dev.mutex);
 256                 return -EFAULT;
 257         }
 258         n->dev.acked_features = features;
 259         smp_wmb();
 260         vhost_test_flush(n);
 261         mutex_unlock(&n->dev.mutex);
 262         return 0;
 263 }
 264
 265 static long vhost_test_ioctl(struct file *f, unsigned int ioctl,
 266                              unsigned long arg)
 267 {
 268         struct vhost_test *n = f->private_data;
 269         void __user *argp = (void __user *)arg;
 270         u64 __user *featurep = argp;
 271         int test;
 272         u64 features;
 273         int r;
 274         switch (ioctl) {
 275         case VHOST_TEST_RUN:
 276                 if (copy_from_user(&test, argp, sizeof test))
 277                         return -EFAULT;
 278                 return vhost_test_run(n, test);
 279         case VHOST_GET_FEATURES:
 280                 features = VHOST_FEATURES;
 281                 if (copy_to_user(featurep, &features, sizeof features))
 282                         return -EFAULT;
 283                 return 0;
 284         case VHOST_SET_FEATURES:
 285                 if (copy_from_user(&features, featurep, sizeof features))
 286                         return -EFAULT;
 287                 if (features & ~VHOST_FEATURES)
 288                         return -EOPNOTSUPP;
 289                 return vhost_test_set_features(n, features);
 290         case VHOST_RESET_OWNER:
 291                 return vhost_test_reset_owner(n);
 292         default:
 293                 mutex_lock(&n->dev.mutex);
 294                 r = vhost_dev_ioctl(&n->dev, ioctl, argp);
 295                 if (r == -ENOIOCTLCMD)
 296                         r = vhost_vring_ioctl(&n->dev, ioctl, argp);
 297                 vhost_test_flush(n);
 298                 mutex_unlock(&n->dev.mutex);
 299                 return r;
 300         }
 301 }
 302
 303 #ifdef CONFIG_COMPAT
 304 static long vhost_test_compat_ioctl(struct file *f, unsigned int ioctl,
 305                                    unsigned long arg)
 306 {
 307         return vhost_test_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
 308 }
 309 #endif
 310
 311 static const struct file_operations vhost_test_fops = {
 312         .owner          = THIS_MODULE,
 313         .release        = vhost_test_release,
 314         .unlocked_ioctl = vhost_test_ioctl,
 315 #ifdef CONFIG_COMPAT
 316         .compat_ioctl   = vhost_test_compat_ioctl,
 317 #endif
 318         .open           = vhost_test_open,
 319         .llseek         = noop_llseek,
 320 };
 321
 322 static struct miscdevice vhost_test_misc = {
 323         MISC_DYNAMIC_MINOR,
 324         "vhost-test",
 325         &vhost_test_fops,
 326 };
 327
 328 static int vhost_test_init(void)
 329 {
 330         return misc_register(&vhost_test_misc);
 331 }
 332 module_init(vhost_test_init);
 333
 334 static void vhost_test_exit(void)
 335 {
 336         misc_deregister(&vhost_test_misc);
 337 }
 338 module_exit(vhost_test_exit);
 339
 340 MODULE_VERSION("0.0.1");
 341 MODULE_LICENSE("GPL v2");
 342 MODULE_AUTHOR("Michael S. Tsirkin");
 343 MODULE_DESCRIPTION("Host kernel side for virtio simulator");