connection.c revision 46a971913611a23478283931460a95be962ce329 
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
34#include "hyperv_vmbus.h"
35
36
37struct 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 */
45int 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
164cleanup:
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 */
190struct 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 */
211static 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 */
248void 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 */
283int 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 */
310int 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