summaryrefslogtreecommitdiff
path: root/drivers/hv/connection.c
blob: ac71653abb77875556fbd17dc72a8195f14447d7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
/*
 *
 * Copyright (c) 2009, Microsoft Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA 02111-1307 USA.
 *
 * Authors:
 *   Haiyang Zhang <haiyangz@microsoft.com>
 *   Hank Janssen  <hjanssen@microsoft.com>
 *
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/delay.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/hyperv.h>
#include <linux/export.h>
#include <asm/hyperv.h>
#include "hyperv_vmbus.h"


struct vmbus_connection vmbus_connection = {
	.conn_state		= DISCONNECTED,
	.next_gpadl_handle	= ATOMIC_INIT(0xE1E10),
};

/*
 * Negotiated protocol version with the host.
 */
__u32 vmbus_proto_version;
EXPORT_SYMBOL_GPL(vmbus_proto_version);

static __u32 vmbus_get_next_version(__u32 current_version)
{
	switch (current_version) {
	case (VERSION_WIN7):
		return VERSION_WS2008;

	case (VERSION_WIN8):
		return VERSION_WIN7;

	case (VERSION_WS2008):
	default:
		return VERSION_INVAL;
	}
}

static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
					__u32 version)
{
	int ret = 0;
	struct vmbus_channel_initiate_contact *msg;
	unsigned long flags;
	int t;

	init_completion(&msginfo->waitevent);

	msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;

	msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
	msg->vmbus_version_requested = version;
	msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
	msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages);
	msg->monitor_page2 = virt_to_phys(
			(void *)((unsigned long)vmbus_connection.monitor_pages +
				 PAGE_SIZE));

	/*
	 * Add to list before we send the request since we may
	 * receive the response before returning from this routine
	 */
	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
	list_add_tail(&msginfo->msglistentry,
		      &vmbus_connection.chn_msg_list);

	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);

	ret = vmbus_post_msg(msg,
			       sizeof(struct vmbus_channel_initiate_contact));
	if (ret != 0) {
		spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
		list_del(&msginfo->msglistentry);
		spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
					flags);
		return ret;
	}

	/* Wait for the connection response */
	t =  wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
	if (t == 0) {
		spin_lock_irqsave(&vmbus_connection.channelmsg_lock,
				flags);
		list_del(&msginfo->msglistentry);
		spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
					flags);
		return -ETIMEDOUT;
	}

	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
	list_del(&msginfo->msglistentry);
	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);

	/* Check if successful */
	if (msginfo->response.version_response.version_supported) {
		vmbus_connection.conn_state = CONNECTED;
	} else {
		pr_err("Unable to connect, "
			"Version %d not supported by Hyper-V\n",
			version);
		return -ECONNREFUSED;
	}

	return ret;
}

/*
 * vmbus_connect - Sends a connect request on the partition service connection
 */
int vmbus_connect(void)
{
	int ret = 0;
	struct vmbus_channel_msginfo *msginfo = NULL;
	__u32 version;

	/* Initialize the vmbus connection */
	vmbus_connection.conn_state = CONNECTING;
	vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
	if (!vmbus_connection.work_queue) {
		ret = -ENOMEM;
		goto cleanup;
	}

	INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
	spin_lock_init(&vmbus_connection.channelmsg_lock);

	INIT_LIST_HEAD(&vmbus_connection.chn_list);
	spin_lock_init(&vmbus_connection.channel_lock);

	/*
	 * Setup the vmbus event connection for channel interrupt
	 * abstraction stuff
	 */
	vmbus_connection.int_page =
	(void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
	if (vmbus_connection.int_page == NULL) {
		ret = -ENOMEM;
		goto cleanup;
	}

	vmbus_connection.recv_int_page = vmbus_connection.int_page;
	vmbus_connection.send_int_page =
		(void *)((unsigned long)vmbus_connection.int_page +
			(PAGE_SIZE >> 1));

	/*
	 * Setup the monitor notification facility. The 1st page for
	 * parent->child and the 2nd page for child->parent
	 */
	vmbus_connection.monitor_pages =
	(void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 1);
	if (vmbus_connection.monitor_pages == NULL) {
		ret = -ENOMEM;
		goto cleanup;
	}

	msginfo = kzalloc(sizeof(*msginfo) +
			  sizeof(struct vmbus_channel_initiate_contact),
			  GFP_KERNEL);
	if (msginfo == NULL) {
		ret = -ENOMEM;
		goto cleanup;
	}

	/*
	 * Negotiate a compatible VMBUS version number with the
	 * host. We start with the highest number we can support
	 * and work our way down until we negotiate a compatible
	 * version.
	 */

	version = VERSION_WS2008;

	do {
		ret = vmbus_negotiate_version(msginfo, version);
		if (ret == 0)
			break;

		version = vmbus_get_next_version(version);
	} while (version != VERSION_INVAL);

	if (version == VERSION_INVAL)
		goto cleanup;

	vmbus_proto_version = version;
	pr_info("Negotiated host information %d\n", version);
	kfree(msginfo);
	return 0;

cleanup:
	vmbus_connection.conn_state = DISCONNECTED;

	if (vmbus_connection.work_queue)
		destroy_workqueue(vmbus_connection.work_queue);

	if (vmbus_connection.int_page) {
		free_pages((unsigned long)vmbus_connection.int_page, 0);
		vmbus_connection.int_page = NULL;
	}

	if (vmbus_connection.monitor_pages) {
		free_pages((unsigned long)vmbus_connection.monitor_pages, 1);
		vmbus_connection.monitor_pages = NULL;
	}

	kfree(msginfo);

	return ret;
}


/*
 * relid2channel - Get the channel object given its
 * child relative id (ie channel id)
 */
struct vmbus_channel *relid2channel(u32 relid)
{
	struct vmbus_channel *channel;
	struct vmbus_channel *found_channel  = NULL;
	unsigned long flags;

	spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
	list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
		if (channel->offermsg.child_relid == relid) {
			found_channel = channel;
			break;
		}
	}
	spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);

	return found_channel;
}

/*
 * process_chn_event - Process a channel event notification
 */
static void process_chn_event(u32 relid)
{
	struct vmbus_channel *channel;
	unsigned long flags;
	void *arg;
	bool read_state;
	u32 bytes_to_read;

	/*
	 * Find the channel based on this relid and invokes the
	 * channel callback to process the event
	 */
	channel = relid2channel(relid);

	if (!channel) {
		pr_err("channel not found for relid - %u\n", relid);
		return;
	}

	/*
	 * A channel once created is persistent even when there
	 * is no driver handling the device. An unloading driver
	 * sets the onchannel_callback to NULL under the
	 * protection of the channel inbound_lock. Thus, checking
	 * and invoking the driver specific callback takes care of
	 * orderly unloading of the driver.
	 */

	spin_lock_irqsave(&channel->inbound_lock, flags);
	if (channel->onchannel_callback != NULL) {
		arg = channel->channel_callback_context;
		read_state = channel->batched_reading;
		/*
		 * This callback reads the messages sent by the host.
		 * We can optimize host to guest signaling by ensuring:
		 * 1. While reading the channel, we disable interrupts from
		 *    host.
		 * 2. Ensure that we process all posted messages from the host
		 *    before returning from this callback.
		 * 3. Once we return, enable signaling from the host. Once this
		 *    state is set we check to see if additional packets are
		 *    available to read. In this case we repeat the process.
		 */

		do {
			hv_begin_read(&channel->inbound);
			channel->onchannel_callback(arg);
			bytes_to_read = hv_end_read(&channel->inbound);
		} while (read_state && (bytes_to_read != 0));
	} else {
		pr_err("no channel callback for relid - %u\n", relid);
	}

	spin_unlock_irqrestore(&channel->inbound_lock, flags);
}

/*
 * vmbus_on_event - Handler for events
 */
void vmbus_on_event(unsigned long data)
{
	u32 dword;
	u32 maxdword;
	int bit;
	u32 relid;
	u32 *recv_int_page = NULL;
	void *page_addr;
	int cpu = smp_processor_id();
	union hv_synic_event_flags *event;

	if ((vmbus_proto_version == VERSION_WS2008) ||
		(vmbus_proto_version == VERSION_WIN7)) {
		maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
		recv_int_page = vmbus_connection.recv_int_page;
	} else {
		/*
		 * When the host is win8 and beyond, the event page
		 * can be directly checked to get the id of the channel
		 * that has the interrupt pending.
		 */
		maxdword = HV_EVENT_FLAGS_DWORD_COUNT;
		page_addr = hv_context.synic_event_page[cpu];
		event = (union hv_synic_event_flags *)page_addr +
						 VMBUS_MESSAGE_SINT;
		recv_int_page = event->flags32;
	}



	/* Check events */
	if (!recv_int_page)
		return;
	for (dword = 0; dword < maxdword; dword++) {
		if (!recv_int_page[dword])
			continue;
		for (bit = 0; bit < 32; bit++) {
			if (sync_test_and_clear_bit(bit,
				(unsigned long *)&recv_int_page[dword])) {
				relid = (dword << 5) + bit;

				if (relid == 0)
					/*
					 * Special case - vmbus
					 * channel protocol msg
					 */
					continue;

				process_chn_event(relid);
			}
		}
	}
}

/*
 * vmbus_post_msg - Send a msg on the vmbus's message connection
 */
int vmbus_post_msg(void *buffer, size_t buflen)
{
	union hv_connection_id conn_id;
	int ret = 0;
	int retries = 0;

	conn_id.asu32 = 0;
	conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;

	/*
	 * hv_post_message() can have transient failures because of
	 * insufficient resources. Retry the operation a couple of
	 * times before giving up.
	 */
	while (retries < 3) {
		ret =  hv_post_message(conn_id, 1, buffer, buflen);
		if (ret != HV_STATUS_INSUFFICIENT_BUFFERS)
			return ret;
		retries++;
		msleep(100);
	}
	return ret;
}

/*
 * vmbus_set_event - Send an event notification to the parent
 */
int vmbus_set_event(struct vmbus_channel *channel)
{
	u32 child_relid = channel->offermsg.child_relid;

	if (!channel->is_dedicated_interrupt) {
		/* Each u32 represents 32 channels */
		sync_set_bit(child_relid & 31,
			(unsigned long *)vmbus_connection.send_int_page +
			(child_relid >> 5));
	}

	return hv_signal_event(channel->sig_event);
}