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(struct vhost_test * n)147 static void vhost_test_flush(struct vhost_test *n)
148 {
149 vhost_dev_flush(&n->dev);
150 }
151
vhost_test_release(struct inode * inode,struct file * f)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
vhost_test_run(struct vhost_test * n,int test)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
vhost_test_reset_owner(struct vhost_test * n)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
vhost_test_set_features(struct vhost_test * n,u64 features)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
vhost_test_set_backend(struct vhost_test * n,unsigned index,int fd)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
vhost_test_ioctl(struct file * f,unsigned int ioctl,unsigned long arg)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");
374