drivers/vhost/test.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright (C) 2009 Red Hat, Inc.
   3  * Author: Michael S. Tsirkin <mst@redhat.com>
   4  *
   5  * test virtio server in host kernel.
   6  */
   7
   8 #include <linux/compat.h>
   9 #include <linux/eventfd.h>
  10 #include <linux/vhost.h>
  11 #include <linux/miscdevice.h>
  12 #include <linux/module.h>
  13 #include <linux/mutex.h>
  14 #include <linux/workqueue.h>
  15 #include <linux/file.h>
  16 #include <linux/slab.h>
  17
  18 #include "test.h"
  19 #include "vhost.h"
  20
  21 /* Max number of bytes transferred before requeueing the job.
  22  * Using this limit prevents one virtqueue from starving others. */
  23 #define VHOST_TEST_WEIGHT 0x80000
  24
  25 /* Max number of packets transferred before requeueing the job.
  26  * Using this limit prevents one virtqueue from starving others with
  27  * pkts.
  28  */
  29 #define VHOST_TEST_PKT_WEIGHT 256
  30
  31 enum {
  32         VHOST_TEST_VQ = 0,
  33         VHOST_TEST_VQ_MAX = 1,
  34 };
  35
  36 struct vhost_test {
  37         struct vhost_dev dev;
  38         struct vhost_virtqueue vqs[VHOST_TEST_VQ_MAX];
  39 };
  40
  41 /* Expects to be always run from workqueue - which acts as
  42  * read-size critical section for our kind of RCU. */
  43 static void handle_vq(struct vhost_test *n)
  44 {
  45         struct vhost_virtqueue *vq = &n->vqs[VHOST_TEST_VQ];
  46         unsigned out, in;
  47         int head;
  48         size_t len, total_len = 0;
  49         void *private;
  50
  51         mutex_lock(&vq->mutex);
  52         private = vhost_vq_get_backend(vq);
  53         if (!private) {
  54                 mutex_unlock(&vq->mutex);
  55                 return;
  56         }
  57
  58         vhost_disable_notify(&n->dev, vq);
  59
  60         for (;;) {
  61                 head = vhost_get_vq_desc(vq, vq->iov,
  62                                          ARRAY_SIZE(vq->iov),
  63                                          &out, &in,
  64                                          NULL, NULL);
  65                 /* On error, stop handling until the next kick. */
  66                 if (unlikely(head < 0))
  67                         break;
  68                 /* Nothing new?  Wait for eventfd to tell us they refilled. */
  69                 if (head == vq->num) {
  70                         if (unlikely(vhost_enable_notify(&n->dev, vq))) {
  71                                 vhost_disable_notify(&n->dev, vq);
  72                                 continue;
  73                         }
  74                         break;
  75                 }
  76                 if (in) {
  77                         vq_err(vq, "Unexpected descriptor format for TX: "
  78                                "out %d, int %d\n", out, in);
  79                         break;
  80                 }
  81                 len = iov_length(vq->iov, out);
  82                 /* Sanity check */
  83                 if (!len) {
  84                         vq_err(vq, "Unexpected 0 len for TX\n");
  85                         break;
  86                 }
  87                 vhost_add_used_and_signal(&n->dev, vq, head, 0);
  88                 total_len += len;
  89                 if (unlikely(vhost_exceeds_weight(vq, 0, total_len)))
  90                         break;
  91         }
  92
  93         mutex_unlock(&vq->mutex);
  94 }
  95
  96 static void handle_vq_kick(struct vhost_work *work)
  97 {
  98         struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
  99                                                   poll.work);
 100         struct vhost_test *n = container_of(vq->dev, struct vhost_test, dev);
 101
 102         handle_vq(n);
 103 }
 104
 105 static int vhost_test_open(struct inode *inode, struct file *f)
 106 {
 107         struct vhost_test *n = kmalloc(sizeof *n, GFP_KERNEL);
 108         struct vhost_dev *dev;
 109         struct vhost_virtqueue **vqs;
 110
 111         if (!n)
 112                 return -ENOMEM;
 113         vqs = kmalloc_array(VHOST_TEST_VQ_MAX, sizeof(*vqs), GFP_KERNEL);
 114         if (!vqs) {
 115                 kfree(n);
 116                 return -ENOMEM;
 117         }
 118
 119         dev = &n->dev;
 120         vqs[VHOST_TEST_VQ] = &n->vqs[VHOST_TEST_VQ];
 121         n->vqs[VHOST_TEST_VQ].handle_kick = handle_vq_kick;
 122         vhost_dev_init(dev, vqs, VHOST_TEST_VQ_MAX, UIO_MAXIOV,
 123                        VHOST_TEST_PKT_WEIGHT, VHOST_TEST_WEIGHT, true, NULL);
 124
 125         f->private_data = n;
 126
 127         return 0;
 128 }
 129
 130 static void *vhost_test_stop_vq(struct vhost_test *n,
 131                                 struct vhost_virtqueue *vq)
 132 {
 133         void *private;
 134
 135         mutex_lock(&vq->mutex);
 136         private = vhost_vq_get_backend(vq);
 137         vhost_vq_set_backend(vq, NULL);
 138         mutex_unlock(&vq->mutex);
 139         return private;
 140 }
 141
 142 static void vhost_test_stop(struct vhost_test *n, void **privatep)
 143 {
 144         *privatep = vhost_test_stop_vq(n, n->vqs + VHOST_TEST_VQ);
 145 }
 146
 147 static void vhost_test_flush(struct vhost_test *n)
 148 {
 149         vhost_dev_flush(&n->dev);
 150 }
 151
 152 static int vhost_test_release(struct inode *inode, struct file *f)
 153 {
 154         struct vhost_test *n = f->private_data;
 155         void  *private;
 156
 157         vhost_test_stop(n, &private);
 158         vhost_test_flush(n);
 159         vhost_dev_stop(&n->dev);
 160         vhost_dev_cleanup(&n->dev);
 161         kfree(n->dev.vqs);
 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 = vhost_vq_get_backend(vq);
 195                 vhost_vq_set_backend(vq, priv);
 196
 197                 r = vhost_vq_init_access(&n->vqs[index]);
 198
 199                 mutex_unlock(&vq->mutex);
 200
 201                 if (r)
 202                         goto err;
 203
 204                 if (oldpriv) {
 205                         vhost_test_flush(n);
 206                 }
 207         }
 208
 209         mutex_unlock(&n->dev.mutex);
 210         return 0;
 211
 212 err:
 213         mutex_unlock(&n->dev.mutex);
 214         return r;
 215 }
 216
 217 static long vhost_test_reset_owner(struct vhost_test *n)
 218 {
 219         void *priv = NULL;
 220         long err;
 221         struct vhost_iotlb *umem;
 222
 223         mutex_lock(&n->dev.mutex);
 224         err = vhost_dev_check_owner(&n->dev);
 225         if (err)
 226                 goto done;
 227         umem = vhost_dev_reset_owner_prepare();
 228         if (!umem) {
 229                 err = -ENOMEM;
 230                 goto done;
 231         }
 232         vhost_test_stop(n, &priv);
 233         vhost_test_flush(n);
 234         vhost_dev_stop(&n->dev);
 235         vhost_dev_reset_owner(&n->dev, umem);
 236 done:
 237         mutex_unlock(&n->dev.mutex);
 238         return err;
 239 }
 240
 241 static int vhost_test_set_features(struct vhost_test *n, u64 features)
 242 {
 243         struct vhost_virtqueue *vq;
 244
 245         mutex_lock(&n->dev.mutex);
 246         if ((features & (1 << VHOST_F_LOG_ALL)) &&
 247             !vhost_log_access_ok(&n->dev)) {
 248                 mutex_unlock(&n->dev.mutex);
 249                 return -EFAULT;
 250         }
 251         vq = &n->vqs[VHOST_TEST_VQ];
 252         mutex_lock(&vq->mutex);
 253         vq->acked_features = features;
 254         mutex_unlock(&vq->mutex);
 255         mutex_unlock(&n->dev.mutex);
 256         return 0;
 257 }
 258
 259 static long vhost_test_set_backend(struct vhost_test *n, unsigned index, int fd)
 260 {
 261         static void *backend;
 262
 263         const bool enable = fd != -1;
 264         struct vhost_virtqueue *vq;
 265         int r;
 266
 267         mutex_lock(&n->dev.mutex);
 268         r = vhost_dev_check_owner(&n->dev);
 269         if (r)
 270                 goto err;
 271
 272         if (index >= VHOST_TEST_VQ_MAX) {
 273                 r = -ENOBUFS;
 274                 goto err;
 275         }
 276         vq = &n->vqs[index];
 277         mutex_lock(&vq->mutex);
 278
 279         /* Verify that ring has been setup correctly. */
 280         if (!vhost_vq_access_ok(vq)) {
 281                 r = -EFAULT;
 282                 goto err_vq;
 283         }
 284         if (!enable) {
 285                 vhost_poll_stop(&vq->poll);
 286                 backend = vhost_vq_get_backend(vq);
 287                 vhost_vq_set_backend(vq, NULL);
 288         } else {
 289                 vhost_vq_set_backend(vq, backend);
 290                 r = vhost_vq_init_access(vq);
 291                 if (r == 0)
 292                         r = vhost_poll_start(&vq->poll, vq->kick);
 293         }
 294
 295         mutex_unlock(&vq->mutex);
 296
 297         if (enable) {
 298                 vhost_test_flush(n);
 299         }
 300
 301         mutex_unlock(&n->dev.mutex);
 302         return 0;
 303
 304 err_vq:
 305         mutex_unlock(&vq->mutex);
 306 err:
 307         mutex_unlock(&n->dev.mutex);
 308         return r;
 309 }
 310
 311 static long vhost_test_ioctl(struct file *f, unsigned int ioctl,
 312                              unsigned long arg)
 313 {
 314         struct vhost_vring_file backend;
 315         struct vhost_test *n = f->private_data;
 316         void __user *argp = (void __user *)arg;
 317         u64 __user *featurep = argp;
 318         int test;
 319         u64 features;
 320         int r;
 321         switch (ioctl) {
 322         case VHOST_TEST_RUN:
 323                 if (copy_from_user(&test, argp, sizeof test))
 324                         return -EFAULT;
 325                 return vhost_test_run(n, test);
 326         case VHOST_TEST_SET_BACKEND:
 327                 if (copy_from_user(&backend, argp, sizeof backend))
 328                         return -EFAULT;
 329                 return vhost_test_set_backend(n, backend.index, backend.fd);
 330         case VHOST_GET_FEATURES:
 331                 features = VHOST_FEATURES;
 332                 if (copy_to_user(featurep, &features, sizeof features))
 333                         return -EFAULT;
 334                 return 0;
 335         case VHOST_SET_FEATURES:
 336                 if (copy_from_user(&features, featurep, sizeof features))
 337                         return -EFAULT;
 338                 if (features & ~VHOST_FEATURES)
 339                         return -EOPNOTSUPP;
 340                 return vhost_test_set_features(n, features);
 341         case VHOST_RESET_OWNER:
 342                 return vhost_test_reset_owner(n);
 343         default:
 344                 mutex_lock(&n->dev.mutex);
 345                 r = vhost_dev_ioctl(&n->dev, ioctl, argp);
 346                 if (r == -ENOIOCTLCMD)
 347                         r = vhost_vring_ioctl(&n->dev, ioctl, argp);
 348                 vhost_test_flush(n);
 349                 mutex_unlock(&n->dev.mutex);
 350                 return r;
 351         }
 352 }
 353
 354 static const struct file_operations vhost_test_fops = {
 355         .owner          = THIS_MODULE,
 356         .release        = vhost_test_release,
 357         .unlocked_ioctl = vhost_test_ioctl,
 358         .compat_ioctl   = compat_ptr_ioctl,
 359         .open           = vhost_test_open,
 360         .llseek         = noop_llseek,
 361 };
 362
 363 static struct miscdevice vhost_test_misc = {
 364         MISC_DYNAMIC_MINOR,
 365         "vhost-test",
 366         &vhost_test_fops,
 367 };
 368 module_misc_device(vhost_test_misc);
 369
 370 MODULE_VERSION("0.0.1");
 371 MODULE_LICENSE("GPL v2");
 372 MODULE_AUTHOR("Michael S. Tsirkin");
 373 MODULE_DESCRIPTION("Host kernel side for virtio simulator");