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. */
handle_vq(struct vhost_test * n)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
handle_vq_kick(struct vhost_work * work)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
vhost_test_open(struct inode * inode,struct file * f)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
vhost_test_stop_vq(struct vhost_test * n,struct vhost_virtqueue * vq)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
vhost_test_stop(struct vhost_test * n,void ** privatep)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
vhost_test_flush_vq(struct vhost_test * n,int index)147 static void vhost_test_flush_vq(struct vhost_test *n, int index)
148 {
149 vhost_poll_flush(&n->vqs[index].poll);
150 }
151
vhost_test_flush(struct vhost_test * n)152 static void vhost_test_flush(struct vhost_test *n)
153 {
154 vhost_test_flush_vq(n, VHOST_TEST_VQ);
155 }
156
vhost_test_release(struct inode * inode,struct file * f)157 static int vhost_test_release(struct inode *inode, struct file *f)
158 {
159 struct vhost_test *n = f->private_data;
160 void *private;
161
162 vhost_test_stop(n, &private);
163 vhost_test_flush(n);
164 vhost_dev_stop(&n->dev);
165 vhost_dev_cleanup(&n->dev);
166 /* We do an extra flush before freeing memory,
167 * since jobs can re-queue themselves. */
168 vhost_test_flush(n);
169 kfree(n);
170 return 0;
171 }
172
vhost_test_run(struct vhost_test * n,int test)173 static long vhost_test_run(struct vhost_test *n, int test)
174 {
175 void *priv, *oldpriv;
176 struct vhost_virtqueue *vq;
177 int r, index;
178
179 if (test < 0 || test > 1)
180 return -EINVAL;
181
182 mutex_lock(&n->dev.mutex);
183 r = vhost_dev_check_owner(&n->dev);
184 if (r)
185 goto err;
186
187 for (index = 0; index < n->dev.nvqs; ++index) {
188 /* Verify that ring has been setup correctly. */
189 if (!vhost_vq_access_ok(&n->vqs[index])) {
190 r = -EFAULT;
191 goto err;
192 }
193 }
194
195 for (index = 0; index < n->dev.nvqs; ++index) {
196 vq = n->vqs + index;
197 mutex_lock(&vq->mutex);
198 priv = test ? n : NULL;
199
200 /* start polling new socket */
201 oldpriv = vhost_vq_get_backend(vq);
202 vhost_vq_set_backend(vq, priv);
203
204 r = vhost_vq_init_access(&n->vqs[index]);
205
206 mutex_unlock(&vq->mutex);
207
208 if (r)
209 goto err;
210
211 if (oldpriv) {
212 vhost_test_flush_vq(n, index);
213 }
214 }
215
216 mutex_unlock(&n->dev.mutex);
217 return 0;
218
219 err:
220 mutex_unlock(&n->dev.mutex);
221 return r;
222 }
223
vhost_test_reset_owner(struct vhost_test * n)224 static long vhost_test_reset_owner(struct vhost_test *n)
225 {
226 void *priv = NULL;
227 long err;
228 struct vhost_iotlb *umem;
229
230 mutex_lock(&n->dev.mutex);
231 err = vhost_dev_check_owner(&n->dev);
232 if (err)
233 goto done;
234 umem = vhost_dev_reset_owner_prepare();
235 if (!umem) {
236 err = -ENOMEM;
237 goto done;
238 }
239 vhost_test_stop(n, &priv);
240 vhost_test_flush(n);
241 vhost_dev_stop(&n->dev);
242 vhost_dev_reset_owner(&n->dev, umem);
243 done:
244 mutex_unlock(&n->dev.mutex);
245 return err;
246 }
247
vhost_test_set_features(struct vhost_test * n,u64 features)248 static int vhost_test_set_features(struct vhost_test *n, u64 features)
249 {
250 struct vhost_virtqueue *vq;
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 vq = &n->vqs[VHOST_TEST_VQ];
259 mutex_lock(&vq->mutex);
260 vq->acked_features = features;
261 mutex_unlock(&vq->mutex);
262 mutex_unlock(&n->dev.mutex);
263 return 0;
264 }
265
vhost_test_set_backend(struct vhost_test * n,unsigned index,int fd)266 static long vhost_test_set_backend(struct vhost_test *n, unsigned index, int fd)
267 {
268 static void *backend;
269
270 const bool enable = fd != -1;
271 struct vhost_virtqueue *vq;
272 int r;
273
274 mutex_lock(&n->dev.mutex);
275 r = vhost_dev_check_owner(&n->dev);
276 if (r)
277 goto err;
278
279 if (index >= VHOST_TEST_VQ_MAX) {
280 r = -ENOBUFS;
281 goto err;
282 }
283 vq = &n->vqs[index];
284 mutex_lock(&vq->mutex);
285
286 /* Verify that ring has been setup correctly. */
287 if (!vhost_vq_access_ok(vq)) {
288 r = -EFAULT;
289 goto err_vq;
290 }
291 if (!enable) {
292 vhost_poll_stop(&vq->poll);
293 backend = vhost_vq_get_backend(vq);
294 vhost_vq_set_backend(vq, NULL);
295 } else {
296 vhost_vq_set_backend(vq, backend);
297 r = vhost_vq_init_access(vq);
298 if (r == 0)
299 r = vhost_poll_start(&vq->poll, vq->kick);
300 }
301
302 mutex_unlock(&vq->mutex);
303
304 if (enable) {
305 vhost_test_flush_vq(n, index);
306 }
307
308 mutex_unlock(&n->dev.mutex);
309 return 0;
310
311 err_vq:
312 mutex_unlock(&vq->mutex);
313 err:
314 mutex_unlock(&n->dev.mutex);
315 return r;
316 }
317
vhost_test_ioctl(struct file * f,unsigned int ioctl,unsigned long arg)318 static long vhost_test_ioctl(struct file *f, unsigned int ioctl,
319 unsigned long arg)
320 {
321 struct vhost_vring_file backend;
322 struct vhost_test *n = f->private_data;
323 void __user *argp = (void __user *)arg;
324 u64 __user *featurep = argp;
325 int test;
326 u64 features;
327 int r;
328 switch (ioctl) {
329 case VHOST_TEST_RUN:
330 if (copy_from_user(&test, argp, sizeof test))
331 return -EFAULT;
332 return vhost_test_run(n, test);
333 case VHOST_TEST_SET_BACKEND:
334 if (copy_from_user(&backend, argp, sizeof backend))
335 return -EFAULT;
336 return vhost_test_set_backend(n, backend.index, backend.fd);
337 case VHOST_GET_FEATURES:
338 features = VHOST_FEATURES;
339 if (copy_to_user(featurep, &features, sizeof features))
340 return -EFAULT;
341 return 0;
342 case VHOST_SET_FEATURES:
343 printk(KERN_ERR "1\n");
344 if (copy_from_user(&features, featurep, sizeof features))
345 return -EFAULT;
346 printk(KERN_ERR "2\n");
347 if (features & ~VHOST_FEATURES)
348 return -EOPNOTSUPP;
349 printk(KERN_ERR "3\n");
350 return vhost_test_set_features(n, features);
351 case VHOST_RESET_OWNER:
352 return vhost_test_reset_owner(n);
353 default:
354 mutex_lock(&n->dev.mutex);
355 r = vhost_dev_ioctl(&n->dev, ioctl, argp);
356 if (r == -ENOIOCTLCMD)
357 r = vhost_vring_ioctl(&n->dev, ioctl, argp);
358 vhost_test_flush(n);
359 mutex_unlock(&n->dev.mutex);
360 return r;
361 }
362 }
363
364 static const struct file_operations vhost_test_fops = {
365 .owner = THIS_MODULE,
366 .release = vhost_test_release,
367 .unlocked_ioctl = vhost_test_ioctl,
368 .compat_ioctl = compat_ptr_ioctl,
369 .open = vhost_test_open,
370 .llseek = noop_llseek,
371 };
372
373 static struct miscdevice vhost_test_misc = {
374 MISC_DYNAMIC_MINOR,
375 "vhost-test",
376 &vhost_test_fops,
377 };
378 module_misc_device(vhost_test_misc);
379
380 MODULE_VERSION("0.0.1");
381 MODULE_LICENSE("GPL v2");
382 MODULE_AUTHOR("Michael S. Tsirkin");
383 MODULE_DESCRIPTION("Host kernel side for virtio simulator");
384