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 enum {
  26         VHOST_TEST_VQ = 0,
  27         VHOST_TEST_VQ_MAX = 1,
  28 };
  29
  30 struct vhost_test {
  31         struct vhost_dev dev;
  32         struct vhost_virtqueue vqs[VHOST_TEST_VQ_MAX];
  33 };
  34
  35 /* Expects to be always run from workqueue - which acts as
  36  * read-size critical section for our kind of RCU. */
  37 static void handle_vq(struct vhost_test *n)
  38 {
  39         struct vhost_virtqueue *vq = &n->vqs[VHOST_TEST_VQ];
  40         unsigned out, in;
  41         int head;
  42         size_t len, total_len = 0;
  43         void *private;
  44
  45         mutex_lock(&vq->mutex);
  46         private = vq->private_data;
  47         if (!private) {
  48                 mutex_unlock(&vq->mutex);
  49                 return;
  50         }
  51
  52         vhost_disable_notify(&n->dev, vq);
  53
  54         for (;;) {
  55                 head = vhost_get_vq_desc(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         struct vhost_virtqueue **vqs;
 106
 107         if (!n)
 108                 return -ENOMEM;
 109         vqs = kmalloc_array(VHOST_TEST_VQ_MAX, sizeof(*vqs), GFP_KERNEL);
 110         if (!vqs) {
 111                 kfree(n);
 112                 return -ENOMEM;
 113         }
 114
 115         dev = &n->dev;
 116         vqs[VHOST_TEST_VQ] = &n->vqs[VHOST_TEST_VQ];
 117         n->vqs[VHOST_TEST_VQ].handle_kick = handle_vq_kick;
 118         vhost_dev_init(dev, vqs, VHOST_TEST_VQ_MAX);
 119
 120         f->private_data = n;
 121
 122         return 0;
 123 }
 124
 125 static void *vhost_test_stop_vq(struct vhost_test *n,
 126                                 struct vhost_virtqueue *vq)
 127 {
 128         void *private;
 129
 130         mutex_lock(&vq->mutex);
 131         private = vq->private_data;
 132         vq->private_data = NULL;
 133         mutex_unlock(&vq->mutex);
 134         return private;
 135 }
 136
 137 static void vhost_test_stop(struct vhost_test *n, void **privatep)
 138 {
 139         *privatep = vhost_test_stop_vq(n, n->vqs + VHOST_TEST_VQ);
 140 }
 141
 142 static void vhost_test_flush_vq(struct vhost_test *n, int index)
 143 {
 144         vhost_poll_flush(&n->vqs[index].poll);
 145 }
 146
 147 static void vhost_test_flush(struct vhost_test *n)
 148 {
 149         vhost_test_flush_vq(n, VHOST_TEST_VQ);
 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_cleanup(&n->dev);
 160         /* We do an extra flush before freeing memory,
 161          * since jobs can re-queue themselves. */
 162         vhost_test_flush(n);
 163         kfree(n);
 164         return 0;
 165 }
 166
 167 static long vhost_test_run(struct vhost_test *n, int test)
 168 {
 169         void *priv, *oldpriv;
 170         struct vhost_virtqueue *vq;
 171         int r, index;
 172
 173         if (test < 0 || test > 1)
 174                 return -EINVAL;
 175
 176         mutex_lock(&n->dev.mutex);
 177         r = vhost_dev_check_owner(&n->dev);
 178         if (r)
 179                 goto err;
 180
 181         for (index = 0; index < n->dev.nvqs; ++index) {
 182                 /* Verify that ring has been setup correctly. */
 183                 if (!vhost_vq_access_ok(&n->vqs[index])) {
 184                         r = -EFAULT;
 185                         goto err;
 186                 }
 187         }
 188
 189         for (index = 0; index < n->dev.nvqs; ++index) {
 190                 vq = n->vqs + index;
 191                 mutex_lock(&vq->mutex);
 192                 priv = test ? n : NULL;
 193
 194                 /* start polling new socket */
 195                 oldpriv = vq->private_data;
 196                 vq->private_data = priv;
 197
 198                 r = vhost_vq_init_access(&n->vqs[index]);
 199
 200                 mutex_unlock(&vq->mutex);
 201
 202                 if (r)
 203                         goto err;
 204
 205                 if (oldpriv) {
 206                         vhost_test_flush_vq(n, index);
 207                 }
 208         }
 209
 210         mutex_unlock(&n->dev.mutex);
 211         return 0;
 212
 213 err:
 214         mutex_unlock(&n->dev.mutex);
 215         return r;
 216 }
 217
 218 static long vhost_test_reset_owner(struct vhost_test *n)
 219 {
 220         void *priv = NULL;
 221         long err;
 222         struct vhost_umem *umem;
 223
 224         mutex_lock(&n->dev.mutex);
 225         err = vhost_dev_check_owner(&n->dev);
 226         if (err)
 227                 goto done;
 228         umem = vhost_dev_reset_owner_prepare();
 229         if (!umem) {
 230                 err = -ENOMEM;
 231                 goto done;
 232         }
 233         vhost_test_stop(n, &priv);
 234         vhost_test_flush(n);
 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_ioctl(struct file *f, unsigned int ioctl,
 260                              unsigned long arg)
 261 {
 262         struct vhost_test *n = f->private_data;
 263         void __user *argp = (void __user *)arg;
 264         u64 __user *featurep = argp;
 265         int test;
 266         u64 features;
 267         int r;
 268         switch (ioctl) {
 269         case VHOST_TEST_RUN:
 270                 if (copy_from_user(&test, argp, sizeof test))
 271                         return -EFAULT;
 272                 return vhost_test_run(n, test);
 273         case VHOST_GET_FEATURES:
 274                 features = VHOST_FEATURES;
 275                 if (copy_to_user(featurep, &features, sizeof features))
 276                         return -EFAULT;
 277                 return 0;
 278         case VHOST_SET_FEATURES:
 279                 printk(KERN_ERR "1\n");
 280                 if (copy_from_user(&features, featurep, sizeof features))
 281                         return -EFAULT;
 282                 printk(KERN_ERR "2\n");
 283                 if (features & ~VHOST_FEATURES)
 284                         return -EOPNOTSUPP;
 285                 printk(KERN_ERR "3\n");
 286                 return vhost_test_set_features(n, features);
 287         case VHOST_RESET_OWNER:
 288                 return vhost_test_reset_owner(n);
 289         default:
 290                 mutex_lock(&n->dev.mutex);
 291                 r = vhost_dev_ioctl(&n->dev, ioctl, argp);
 292                 if (r == -ENOIOCTLCMD)
 293                         r = vhost_vring_ioctl(&n->dev, ioctl, argp);
 294                 vhost_test_flush(n);
 295                 mutex_unlock(&n->dev.mutex);
 296                 return r;
 297         }
 298 }
 299
 300 #ifdef CONFIG_COMPAT
 301 static long vhost_test_compat_ioctl(struct file *f, unsigned int ioctl,
 302                                    unsigned long arg)
 303 {
 304         return vhost_test_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
 305 }
 306 #endif
 307
 308 static const struct file_operations vhost_test_fops = {
 309         .owner          = THIS_MODULE,
 310         .release        = vhost_test_release,
 311         .unlocked_ioctl = vhost_test_ioctl,
 312 #ifdef CONFIG_COMPAT
 313         .compat_ioctl   = vhost_test_compat_ioctl,
 314 #endif
 315         .open           = vhost_test_open,
 316         .llseek         = noop_llseek,
 317 };
 318
 319 static struct miscdevice vhost_test_misc = {
 320         MISC_DYNAMIC_MINOR,
 321         "vhost-test",
 322         &vhost_test_fops,
 323 };
 324 module_misc_device(vhost_test_misc);
 325
 326 MODULE_VERSION("0.0.1");
 327 MODULE_LICENSE("GPL v2");
 328 MODULE_AUTHOR("Michael S. Tsirkin");
 329 MODULE_DESCRIPTION("Host kernel side for virtio simulator");