1 /*
2 *
3 * Copyright (c) 2009, Microsoft Corporation.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms and conditions of the GNU General Public License,
7 * version 2, as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
12 * more details.
13 *
14 * You should have received a copy of the GNU General Public License along with
15 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
16 * Place - Suite 330, Boston, MA 02111-1307 USA.
17 *
18 * Authors:
19 * Haiyang Zhang <haiyangz@microsoft.com>
20 * Hank Janssen <hjanssen@microsoft.com>
21 *
22 */
23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24
25 #include <linux/kernel.h>
26 #include <linux/sched.h>
27 #include <linux/wait.h>
28 #include <linux/delay.h>
29 #include <linux/mm.h>
30 #include <linux/slab.h>
31 #include <linux/vmalloc.h>
32 #include <linux/hyperv.h>
33 #include <asm/hyperv.h>
34 #include "hyperv_vmbus.h"
35
36
37 struct vmbus_connection vmbus_connection = {
38 .conn_state = DISCONNECTED,
39 .next_gpadl_handle = ATOMIC_INIT(0xE1E10),
40 };
41
42 /*
43 * vmbus_connect - Sends a connect request on the partition service connection
44 */
vmbus_connect(void)45 int vmbus_connect(void)
46 {
47 int ret = 0;
48 int t;
49 struct vmbus_channel_msginfo *msginfo = NULL;
50 struct vmbus_channel_initiate_contact *msg;
51 unsigned long flags;
52
53 /* Initialize the vmbus connection */
54 vmbus_connection.conn_state = CONNECTING;
55 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
56 if (!vmbus_connection.work_queue) {
57 ret = -ENOMEM;
58 goto cleanup;
59 }
60
61 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
62 spin_lock_init(&vmbus_connection.channelmsg_lock);
63
64 INIT_LIST_HEAD(&vmbus_connection.chn_list);
65 spin_lock_init(&vmbus_connection.channel_lock);
66
67 /*
68 * Setup the vmbus event connection for channel interrupt
69 * abstraction stuff
70 */
71 vmbus_connection.int_page =
72 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
73 if (vmbus_connection.int_page == NULL) {
74 ret = -ENOMEM;
75 goto cleanup;
76 }
77
78 vmbus_connection.recv_int_page = vmbus_connection.int_page;
79 vmbus_connection.send_int_page =
80 (void *)((unsigned long)vmbus_connection.int_page +
81 (PAGE_SIZE >> 1));
82
83 /*
84 * Setup the monitor notification facility. The 1st page for
85 * parent->child and the 2nd page for child->parent
86 */
87 vmbus_connection.monitor_pages =
88 (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 1);
89 if (vmbus_connection.monitor_pages == NULL) {
90 ret = -ENOMEM;
91 goto cleanup;
92 }
93
94 msginfo = kzalloc(sizeof(*msginfo) +
95 sizeof(struct vmbus_channel_initiate_contact),
96 GFP_KERNEL);
97 if (msginfo == NULL) {
98 ret = -ENOMEM;
99 goto cleanup;
100 }
101
102 init_completion(&msginfo->waitevent);
103
104 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
105
106 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
107 msg->vmbus_version_requested = VMBUS_REVISION_NUMBER;
108 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
109 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages);
110 msg->monitor_page2 = virt_to_phys(
111 (void *)((unsigned long)vmbus_connection.monitor_pages +
112 PAGE_SIZE));
113
114 /*
115 * Add to list before we send the request since we may
116 * receive the response before returning from this routine
117 */
118 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
119 list_add_tail(&msginfo->msglistentry,
120 &vmbus_connection.chn_msg_list);
121
122 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
123
124 ret = vmbus_post_msg(msg,
125 sizeof(struct vmbus_channel_initiate_contact));
126 if (ret != 0) {
127 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
128 list_del(&msginfo->msglistentry);
129 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
130 flags);
131 goto cleanup;
132 }
133
134 /* Wait for the connection response */
135 t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
136 if (t == 0) {
137 spin_lock_irqsave(&vmbus_connection.channelmsg_lock,
138 flags);
139 list_del(&msginfo->msglistentry);
140 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
141 flags);
142 ret = -ETIMEDOUT;
143 goto cleanup;
144 }
145
146 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
147 list_del(&msginfo->msglistentry);
148 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
149
150 /* Check if successful */
151 if (msginfo->response.version_response.version_supported) {
152 vmbus_connection.conn_state = CONNECTED;
153 } else {
154 pr_err("Unable to connect, "
155 "Version %d not supported by Hyper-V\n",
156 VMBUS_REVISION_NUMBER);
157 ret = -ECONNREFUSED;
158 goto cleanup;
159 }
160
161 kfree(msginfo);
162 return 0;
163
164 cleanup:
165 vmbus_connection.conn_state = DISCONNECTED;
166
167 if (vmbus_connection.work_queue)
168 destroy_workqueue(vmbus_connection.work_queue);
169
170 if (vmbus_connection.int_page) {
171 free_pages((unsigned long)vmbus_connection.int_page, 0);
172 vmbus_connection.int_page = NULL;
173 }
174
175 if (vmbus_connection.monitor_pages) {
176 free_pages((unsigned long)vmbus_connection.monitor_pages, 1);
177 vmbus_connection.monitor_pages = NULL;
178 }
179
180 kfree(msginfo);
181
182 return ret;
183 }
184
185
186 /*
187 * relid2channel - Get the channel object given its
188 * child relative id (ie channel id)
189 */
relid2channel(u32 relid)190 struct vmbus_channel *relid2channel(u32 relid)
191 {
192 struct vmbus_channel *channel;
193 struct vmbus_channel *found_channel = NULL;
194 unsigned long flags;
195
196 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
197 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
198 if (channel->offermsg.child_relid == relid) {
199 found_channel = channel;
200 break;
201 }
202 }
203 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
204
205 return found_channel;
206 }
207
208 /*
209 * process_chn_event - Process a channel event notification
210 */
process_chn_event(u32 relid)211 static void process_chn_event(u32 relid)
212 {
213 struct vmbus_channel *channel;
214 unsigned long flags;
215
216 /*
217 * Find the channel based on this relid and invokes the
218 * channel callback to process the event
219 */
220 channel = relid2channel(relid);
221
222 if (!channel) {
223 pr_err("channel not found for relid - %u\n", relid);
224 return;
225 }
226
227 /*
228 * A channel once created is persistent even when there
229 * is no driver handling the device. An unloading driver
230 * sets the onchannel_callback to NULL under the
231 * protection of the channel inbound_lock. Thus, checking
232 * and invoking the driver specific callback takes care of
233 * orderly unloading of the driver.
234 */
235
236 spin_lock_irqsave(&channel->inbound_lock, flags);
237 if (channel->onchannel_callback != NULL)
238 channel->onchannel_callback(channel->channel_callback_context);
239 else
240 pr_err("no channel callback for relid - %u\n", relid);
241
242 spin_unlock_irqrestore(&channel->inbound_lock, flags);
243 }
244
245 /*
246 * vmbus_on_event - Handler for events
247 */
vmbus_on_event(unsigned long data)248 void vmbus_on_event(unsigned long data)
249 {
250 u32 dword;
251 u32 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
252 int bit;
253 u32 relid;
254 u32 *recv_int_page = vmbus_connection.recv_int_page;
255
256 /* Check events */
257 if (!recv_int_page)
258 return;
259 for (dword = 0; dword < maxdword; dword++) {
260 if (!recv_int_page[dword])
261 continue;
262 for (bit = 0; bit < 32; bit++) {
263 if (sync_test_and_clear_bit(bit,
264 (unsigned long *)&recv_int_page[dword])) {
265 relid = (dword << 5) + bit;
266
267 if (relid == 0)
268 /*
269 * Special case - vmbus
270 * channel protocol msg
271 */
272 continue;
273
274 process_chn_event(relid);
275 }
276 }
277 }
278 }
279
280 /*
281 * vmbus_post_msg - Send a msg on the vmbus's message connection
282 */
vmbus_post_msg(void * buffer,size_t buflen)283 int vmbus_post_msg(void *buffer, size_t buflen)
284 {
285 union hv_connection_id conn_id;
286 int ret = 0;
287 int retries = 0;
288
289 conn_id.asu32 = 0;
290 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
291
292 /*
293 * hv_post_message() can have transient failures because of
294 * insufficient resources. Retry the operation a couple of
295 * times before giving up.
296 */
297 while (retries < 3) {
298 ret = hv_post_message(conn_id, 1, buffer, buflen);
299 if (ret != HV_STATUS_INSUFFICIENT_BUFFERS)
300 return ret;
301 retries++;
302 msleep(100);
303 }
304 return ret;
305 }
306
307 /*
308 * vmbus_set_event - Send an event notification to the parent
309 */
vmbus_set_event(u32 child_relid)310 int vmbus_set_event(u32 child_relid)
311 {
312 /* Each u32 represents 32 channels */
313 sync_set_bit(child_relid & 31,
314 (unsigned long *)vmbus_connection.send_int_page +
315 (child_relid >> 5));
316
317 return hv_signal_event();
318 }
319