blob: c235a95152671104cd7042a451b16ccd0d0d06ab [file] [log] [blame]
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -07001/*
2 * Kernel/userspace transport abstraction for Hyper-V util driver.
3 *
4 * Copyright (C) 2015, Vitaly Kuznetsov <vkuznets@redhat.com>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published
8 * by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
13 * NON INFRINGEMENT. See the GNU General Public License for more
14 * details.
15 *
16 */
17
18#include <linux/slab.h>
19#include <linux/fs.h>
20#include <linux/poll.h>
21
22#include "hyperv_vmbus.h"
23#include "hv_utils_transport.h"
24
25static DEFINE_SPINLOCK(hvt_list_lock);
26static struct list_head hvt_list = LIST_HEAD_INIT(hvt_list);
27
28static void hvt_reset(struct hvutil_transport *hvt)
29{
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -070030 kfree(hvt->outmsg);
31 hvt->outmsg = NULL;
32 hvt->outmsg_len = 0;
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -070033 if (hvt->on_reset)
34 hvt->on_reset();
35}
36
37static ssize_t hvt_op_read(struct file *file, char __user *buf,
38 size_t count, loff_t *ppos)
39{
40 struct hvutil_transport *hvt;
41 int ret;
42
43 hvt = container_of(file->f_op, struct hvutil_transport, fops);
44
Vitaly Kuznetsova1502562015-12-14 19:01:55 -080045 if (wait_event_interruptible(hvt->outmsg_q, hvt->outmsg_len > 0 ||
46 hvt->mode != HVUTIL_TRANSPORT_CHARDEV))
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -070047 return -EINTR;
48
Vitaly Kuznetsova72f3a42015-12-14 19:01:54 -080049 mutex_lock(&hvt->lock);
Vitaly Kuznetsova1502562015-12-14 19:01:55 -080050
51 if (hvt->mode == HVUTIL_TRANSPORT_DESTROY) {
52 ret = -EBADF;
53 goto out_unlock;
54 }
55
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -070056 if (!hvt->outmsg) {
57 ret = -EAGAIN;
58 goto out_unlock;
59 }
60
61 if (count < hvt->outmsg_len) {
62 ret = -EINVAL;
63 goto out_unlock;
64 }
65
66 if (!copy_to_user(buf, hvt->outmsg, hvt->outmsg_len))
67 ret = hvt->outmsg_len;
68 else
69 ret = -EFAULT;
70
71 kfree(hvt->outmsg);
72 hvt->outmsg = NULL;
73 hvt->outmsg_len = 0;
74
Vitaly Kuznetsove0fa3e52016-06-09 17:08:57 -070075 if (hvt->on_read)
76 hvt->on_read();
77 hvt->on_read = NULL;
78
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -070079out_unlock:
Vitaly Kuznetsova72f3a42015-12-14 19:01:54 -080080 mutex_unlock(&hvt->lock);
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -070081 return ret;
82}
83
84static ssize_t hvt_op_write(struct file *file, const char __user *buf,
85 size_t count, loff_t *ppos)
86{
87 struct hvutil_transport *hvt;
88 u8 *inmsg;
Vitaly Kuznetsov1f753382015-12-14 19:01:53 -080089 int ret;
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -070090
91 hvt = container_of(file->f_op, struct hvutil_transport, fops);
92
Olaf Heringb0035962015-12-14 16:01:37 -080093 inmsg = memdup_user(buf, count);
94 if (IS_ERR(inmsg))
95 return PTR_ERR(inmsg);
96
Vitaly Kuznetsova1502562015-12-14 19:01:55 -080097 if (hvt->mode == HVUTIL_TRANSPORT_DESTROY)
98 ret = -EBADF;
99 else
100 ret = hvt->on_msg(inmsg, count);
Vitaly Kuznetsov1f753382015-12-14 19:01:53 -0800101
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700102 kfree(inmsg);
103
Vitaly Kuznetsov1f753382015-12-14 19:01:53 -0800104 return ret ? ret : count;
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700105}
106
107static unsigned int hvt_op_poll(struct file *file, poll_table *wait)
108{
109 struct hvutil_transport *hvt;
110
111 hvt = container_of(file->f_op, struct hvutil_transport, fops);
112
113 poll_wait(file, &hvt->outmsg_q, wait);
Vitaly Kuznetsova1502562015-12-14 19:01:55 -0800114
115 if (hvt->mode == HVUTIL_TRANSPORT_DESTROY)
Vitaly Kuznetsov77b744a2015-12-15 16:27:26 -0800116 return POLLERR | POLLHUP;
Vitaly Kuznetsova1502562015-12-14 19:01:55 -0800117
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700118 if (hvt->outmsg_len > 0)
119 return POLLIN | POLLRDNORM;
120
121 return 0;
122}
123
124static int hvt_op_open(struct inode *inode, struct file *file)
125{
126 struct hvutil_transport *hvt;
Vitaly Kuznetsova1502562015-12-14 19:01:55 -0800127 int ret = 0;
128 bool issue_reset = false;
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700129
130 hvt = container_of(file->f_op, struct hvutil_transport, fops);
131
Vitaly Kuznetsova1502562015-12-14 19:01:55 -0800132 mutex_lock(&hvt->lock);
133
134 if (hvt->mode == HVUTIL_TRANSPORT_DESTROY) {
135 ret = -EBADF;
136 } else if (hvt->mode == HVUTIL_TRANSPORT_INIT) {
137 /*
138 * Switching to CHARDEV mode. We switch bach to INIT when
139 * device gets released.
140 */
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700141 hvt->mode = HVUTIL_TRANSPORT_CHARDEV;
Vitaly Kuznetsova1502562015-12-14 19:01:55 -0800142 }
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700143 else if (hvt->mode == HVUTIL_TRANSPORT_NETLINK) {
144 /*
145 * We're switching from netlink communication to using char
146 * device. Issue the reset first.
147 */
Vitaly Kuznetsova1502562015-12-14 19:01:55 -0800148 issue_reset = true;
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700149 hvt->mode = HVUTIL_TRANSPORT_CHARDEV;
Vitaly Kuznetsova1502562015-12-14 19:01:55 -0800150 } else {
151 ret = -EBUSY;
152 }
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700153
Vitaly Kuznetsova1502562015-12-14 19:01:55 -0800154 if (issue_reset)
155 hvt_reset(hvt);
156
157 mutex_unlock(&hvt->lock);
158
159 return ret;
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700160}
161
Vitaly Kuznetsov94200982015-12-14 19:01:56 -0800162static void hvt_transport_free(struct hvutil_transport *hvt)
163{
164 misc_deregister(&hvt->mdev);
165 kfree(hvt->outmsg);
166 kfree(hvt);
167}
168
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700169static int hvt_op_release(struct inode *inode, struct file *file)
170{
171 struct hvutil_transport *hvt;
Vitaly Kuznetsov94200982015-12-14 19:01:56 -0800172 int mode_old;
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700173
174 hvt = container_of(file->f_op, struct hvutil_transport, fops);
175
Vitaly Kuznetsova1502562015-12-14 19:01:55 -0800176 mutex_lock(&hvt->lock);
Vitaly Kuznetsov94200982015-12-14 19:01:56 -0800177 mode_old = hvt->mode;
Vitaly Kuznetsova1502562015-12-14 19:01:55 -0800178 if (hvt->mode != HVUTIL_TRANSPORT_DESTROY)
179 hvt->mode = HVUTIL_TRANSPORT_INIT;
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700180 /*
181 * Cleanup message buffers to avoid spurious messages when the daemon
182 * connects back.
183 */
184 hvt_reset(hvt);
Vitaly Kuznetsova1502562015-12-14 19:01:55 -0800185 mutex_unlock(&hvt->lock);
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700186
Vitaly Kuznetsov94200982015-12-14 19:01:56 -0800187 if (mode_old == HVUTIL_TRANSPORT_DESTROY)
188 hvt_transport_free(hvt);
189
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700190 return 0;
191}
192
193static void hvt_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
194{
195 struct hvutil_transport *hvt, *hvt_found = NULL;
196
197 spin_lock(&hvt_list_lock);
198 list_for_each_entry(hvt, &hvt_list, list) {
199 if (hvt->cn_id.idx == msg->id.idx &&
200 hvt->cn_id.val == msg->id.val) {
201 hvt_found = hvt;
202 break;
203 }
204 }
205 spin_unlock(&hvt_list_lock);
206 if (!hvt_found) {
207 pr_warn("hvt_cn_callback: spurious message received!\n");
208 return;
209 }
210
211 /*
212 * Switching to NETLINK mode. Switching to CHARDEV happens when someone
213 * opens the device.
214 */
Vitaly Kuznetsova1502562015-12-14 19:01:55 -0800215 mutex_lock(&hvt->lock);
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700216 if (hvt->mode == HVUTIL_TRANSPORT_INIT)
217 hvt->mode = HVUTIL_TRANSPORT_NETLINK;
218
219 if (hvt->mode == HVUTIL_TRANSPORT_NETLINK)
220 hvt_found->on_msg(msg->data, msg->len);
221 else
222 pr_warn("hvt_cn_callback: unexpected netlink message!\n");
Vitaly Kuznetsova1502562015-12-14 19:01:55 -0800223 mutex_unlock(&hvt->lock);
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700224}
225
Vitaly Kuznetsove0fa3e52016-06-09 17:08:57 -0700226int hvutil_transport_send(struct hvutil_transport *hvt, void *msg, int len,
227 void (*on_read_cb)(void))
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700228{
229 struct cn_msg *cn_msg;
230 int ret = 0;
231
Vitaly Kuznetsova1502562015-12-14 19:01:55 -0800232 if (hvt->mode == HVUTIL_TRANSPORT_INIT ||
233 hvt->mode == HVUTIL_TRANSPORT_DESTROY) {
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700234 return -EINVAL;
235 } else if (hvt->mode == HVUTIL_TRANSPORT_NETLINK) {
236 cn_msg = kzalloc(sizeof(*cn_msg) + len, GFP_ATOMIC);
Dan Carpenter9dd6a062015-08-01 16:08:17 -0700237 if (!cn_msg)
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700238 return -ENOMEM;
239 cn_msg->id.idx = hvt->cn_id.idx;
240 cn_msg->id.val = hvt->cn_id.val;
241 cn_msg->len = len;
242 memcpy(cn_msg->data, msg, len);
243 ret = cn_netlink_send(cn_msg, 0, 0, GFP_ATOMIC);
244 kfree(cn_msg);
Vitaly Kuznetsove0fa3e52016-06-09 17:08:57 -0700245 /*
246 * We don't know when netlink messages are delivered but unlike
247 * in CHARDEV mode we're not blocked and we can send next
248 * messages right away.
249 */
250 if (on_read_cb)
251 on_read_cb();
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700252 return ret;
253 }
254 /* HVUTIL_TRANSPORT_CHARDEV */
Vitaly Kuznetsova72f3a42015-12-14 19:01:54 -0800255 mutex_lock(&hvt->lock);
Vitaly Kuznetsova1502562015-12-14 19:01:55 -0800256 if (hvt->mode != HVUTIL_TRANSPORT_CHARDEV) {
257 ret = -EINVAL;
258 goto out_unlock;
259 }
260
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700261 if (hvt->outmsg) {
262 /* Previous message wasn't received */
263 ret = -EFAULT;
264 goto out_unlock;
265 }
266 hvt->outmsg = kzalloc(len, GFP_KERNEL);
Olaf Heringcdc0c0c2015-12-14 16:01:36 -0800267 if (hvt->outmsg) {
268 memcpy(hvt->outmsg, msg, len);
269 hvt->outmsg_len = len;
Vitaly Kuznetsove0fa3e52016-06-09 17:08:57 -0700270 hvt->on_read = on_read_cb;
Olaf Heringcdc0c0c2015-12-14 16:01:36 -0800271 wake_up_interruptible(&hvt->outmsg_q);
272 } else
273 ret = -ENOMEM;
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700274out_unlock:
Vitaly Kuznetsova72f3a42015-12-14 19:01:54 -0800275 mutex_unlock(&hvt->lock);
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700276 return ret;
277}
278
279struct hvutil_transport *hvutil_transport_init(const char *name,
280 u32 cn_idx, u32 cn_val,
281 int (*on_msg)(void *, int),
282 void (*on_reset)(void))
283{
284 struct hvutil_transport *hvt;
285
286 hvt = kzalloc(sizeof(*hvt), GFP_KERNEL);
287 if (!hvt)
288 return NULL;
289
290 hvt->cn_id.idx = cn_idx;
291 hvt->cn_id.val = cn_val;
292
293 hvt->mdev.minor = MISC_DYNAMIC_MINOR;
294 hvt->mdev.name = name;
295
296 hvt->fops.owner = THIS_MODULE;
297 hvt->fops.read = hvt_op_read;
298 hvt->fops.write = hvt_op_write;
299 hvt->fops.poll = hvt_op_poll;
300 hvt->fops.open = hvt_op_open;
301 hvt->fops.release = hvt_op_release;
302
303 hvt->mdev.fops = &hvt->fops;
304
305 init_waitqueue_head(&hvt->outmsg_q);
Vitaly Kuznetsova72f3a42015-12-14 19:01:54 -0800306 mutex_init(&hvt->lock);
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700307
308 spin_lock(&hvt_list_lock);
309 list_add(&hvt->list, &hvt_list);
310 spin_unlock(&hvt_list_lock);
311
312 hvt->on_msg = on_msg;
313 hvt->on_reset = on_reset;
314
315 if (misc_register(&hvt->mdev))
316 goto err_free_hvt;
317
318 /* Use cn_id.idx/cn_id.val to determine if we need to setup netlink */
319 if (hvt->cn_id.idx > 0 && hvt->cn_id.val > 0 &&
320 cn_add_callback(&hvt->cn_id, name, hvt_cn_callback))
321 goto err_free_hvt;
322
323 return hvt;
324
325err_free_hvt:
Alex Nge66853b2016-02-26 15:13:20 -0800326 spin_lock(&hvt_list_lock);
327 list_del(&hvt->list);
328 spin_unlock(&hvt_list_lock);
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700329 kfree(hvt);
330 return NULL;
331}
332
333void hvutil_transport_destroy(struct hvutil_transport *hvt)
334{
Vitaly Kuznetsov94200982015-12-14 19:01:56 -0800335 int mode_old;
336
Vitaly Kuznetsova1502562015-12-14 19:01:55 -0800337 mutex_lock(&hvt->lock);
Vitaly Kuznetsov94200982015-12-14 19:01:56 -0800338 mode_old = hvt->mode;
Vitaly Kuznetsova1502562015-12-14 19:01:55 -0800339 hvt->mode = HVUTIL_TRANSPORT_DESTROY;
340 wake_up_interruptible(&hvt->outmsg_q);
341 mutex_unlock(&hvt->lock);
342
Vitaly Kuznetsov94200982015-12-14 19:01:56 -0800343 /*
344 * In case we were in 'chardev' mode we still have an open fd so we
345 * have to defer freeing the device. Netlink interface can be freed
346 * now.
347 */
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700348 spin_lock(&hvt_list_lock);
349 list_del(&hvt->list);
350 spin_unlock(&hvt_list_lock);
351 if (hvt->cn_id.idx > 0 && hvt->cn_id.val > 0)
352 cn_del_callback(&hvt->cn_id);
Vitaly Kuznetsov94200982015-12-14 19:01:56 -0800353
354 if (mode_old != HVUTIL_TRANSPORT_CHARDEV)
355 hvt_transport_free(hvt);
Vitaly Kuznetsov14b50f82015-04-11 18:07:51 -0700356}