Loading...
Note: File does not exist in v3.1.
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 <linux/export.h>
34#include <asm/mshyperv.h>
35
36#include "hyperv_vmbus.h"
37
38
39struct vmbus_connection vmbus_connection = {
40 .conn_state = DISCONNECTED,
41 .next_gpadl_handle = ATOMIC_INIT(0xE1E10),
42};
43EXPORT_SYMBOL_GPL(vmbus_connection);
44
45/*
46 * Negotiated protocol version with the host.
47 */
48__u32 vmbus_proto_version;
49EXPORT_SYMBOL_GPL(vmbus_proto_version);
50
51static __u32 vmbus_get_next_version(__u32 current_version)
52{
53 switch (current_version) {
54 case (VERSION_WIN7):
55 return VERSION_WS2008;
56
57 case (VERSION_WIN8):
58 return VERSION_WIN7;
59
60 case (VERSION_WIN8_1):
61 return VERSION_WIN8;
62
63 case (VERSION_WIN10):
64 return VERSION_WIN8_1;
65
66 case (VERSION_WS2008):
67 default:
68 return VERSION_INVAL;
69 }
70}
71
72static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
73 __u32 version)
74{
75 int ret = 0;
76 struct vmbus_channel_initiate_contact *msg;
77 unsigned long flags;
78
79 init_completion(&msginfo->waitevent);
80
81 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
82
83 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
84 msg->vmbus_version_requested = version;
85 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
86 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
87 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
88 /*
89 * We want all channel messages to be delivered on CPU 0.
90 * This has been the behavior pre-win8. This is not
91 * perf issue and having all channel messages delivered on CPU 0
92 * would be ok.
93 * For post win8 hosts, we support receiving channel messagges on
94 * all the CPUs. This is needed for kexec to work correctly where
95 * the CPU attempting to connect may not be CPU 0.
96 */
97 if (version >= VERSION_WIN8_1) {
98 msg->target_vcpu =
99 hv_cpu_number_to_vp_number(smp_processor_id());
100 vmbus_connection.connect_cpu = smp_processor_id();
101 } else {
102 msg->target_vcpu = 0;
103 vmbus_connection.connect_cpu = 0;
104 }
105
106 /*
107 * Add to list before we send the request since we may
108 * receive the response before returning from this routine
109 */
110 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
111 list_add_tail(&msginfo->msglistentry,
112 &vmbus_connection.chn_msg_list);
113
114 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
115
116 ret = vmbus_post_msg(msg,
117 sizeof(struct vmbus_channel_initiate_contact),
118 true);
119
120 trace_vmbus_negotiate_version(msg, ret);
121
122 if (ret != 0) {
123 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
124 list_del(&msginfo->msglistentry);
125 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
126 flags);
127 return ret;
128 }
129
130 /* Wait for the connection response */
131 wait_for_completion(&msginfo->waitevent);
132
133 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
134 list_del(&msginfo->msglistentry);
135 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
136
137 /* Check if successful */
138 if (msginfo->response.version_response.version_supported) {
139 vmbus_connection.conn_state = CONNECTED;
140 } else {
141 return -ECONNREFUSED;
142 }
143
144 return ret;
145}
146
147/*
148 * vmbus_connect - Sends a connect request on the partition service connection
149 */
150int vmbus_connect(void)
151{
152 int ret = 0;
153 struct vmbus_channel_msginfo *msginfo = NULL;
154 __u32 version;
155
156 /* Initialize the vmbus connection */
157 vmbus_connection.conn_state = CONNECTING;
158 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
159 if (!vmbus_connection.work_queue) {
160 ret = -ENOMEM;
161 goto cleanup;
162 }
163
164 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
165 spin_lock_init(&vmbus_connection.channelmsg_lock);
166
167 INIT_LIST_HEAD(&vmbus_connection.chn_list);
168 mutex_init(&vmbus_connection.channel_mutex);
169
170 /*
171 * Setup the vmbus event connection for channel interrupt
172 * abstraction stuff
173 */
174 vmbus_connection.int_page =
175 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
176 if (vmbus_connection.int_page == NULL) {
177 ret = -ENOMEM;
178 goto cleanup;
179 }
180
181 vmbus_connection.recv_int_page = vmbus_connection.int_page;
182 vmbus_connection.send_int_page =
183 (void *)((unsigned long)vmbus_connection.int_page +
184 (PAGE_SIZE >> 1));
185
186 /*
187 * Setup the monitor notification facility. The 1st page for
188 * parent->child and the 2nd page for child->parent
189 */
190 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
191 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
192 if ((vmbus_connection.monitor_pages[0] == NULL) ||
193 (vmbus_connection.monitor_pages[1] == NULL)) {
194 ret = -ENOMEM;
195 goto cleanup;
196 }
197
198 msginfo = kzalloc(sizeof(*msginfo) +
199 sizeof(struct vmbus_channel_initiate_contact),
200 GFP_KERNEL);
201 if (msginfo == NULL) {
202 ret = -ENOMEM;
203 goto cleanup;
204 }
205
206 /*
207 * Negotiate a compatible VMBUS version number with the
208 * host. We start with the highest number we can support
209 * and work our way down until we negotiate a compatible
210 * version.
211 */
212
213 version = VERSION_CURRENT;
214
215 do {
216 ret = vmbus_negotiate_version(msginfo, version);
217 if (ret == -ETIMEDOUT)
218 goto cleanup;
219
220 if (vmbus_connection.conn_state == CONNECTED)
221 break;
222
223 version = vmbus_get_next_version(version);
224 } while (version != VERSION_INVAL);
225
226 if (version == VERSION_INVAL)
227 goto cleanup;
228
229 vmbus_proto_version = version;
230 pr_info("Vmbus version:%d.%d\n",
231 version >> 16, version & 0xFFFF);
232
233 kfree(msginfo);
234 return 0;
235
236cleanup:
237 pr_err("Unable to connect to host\n");
238
239 vmbus_connection.conn_state = DISCONNECTED;
240 vmbus_disconnect();
241
242 kfree(msginfo);
243
244 return ret;
245}
246
247void vmbus_disconnect(void)
248{
249 /*
250 * First send the unload request to the host.
251 */
252 vmbus_initiate_unload(false);
253
254 if (vmbus_connection.work_queue) {
255 drain_workqueue(vmbus_connection.work_queue);
256 destroy_workqueue(vmbus_connection.work_queue);
257 }
258
259 if (vmbus_connection.int_page) {
260 free_pages((unsigned long)vmbus_connection.int_page, 0);
261 vmbus_connection.int_page = NULL;
262 }
263
264 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
265 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
266 vmbus_connection.monitor_pages[0] = NULL;
267 vmbus_connection.monitor_pages[1] = NULL;
268}
269
270/*
271 * relid2channel - Get the channel object given its
272 * child relative id (ie channel id)
273 */
274struct vmbus_channel *relid2channel(u32 relid)
275{
276 struct vmbus_channel *channel;
277 struct vmbus_channel *found_channel = NULL;
278 struct list_head *cur, *tmp;
279 struct vmbus_channel *cur_sc;
280
281 BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex));
282
283 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
284 if (channel->offermsg.child_relid == relid) {
285 found_channel = channel;
286 break;
287 } else if (!list_empty(&channel->sc_list)) {
288 /*
289 * Deal with sub-channels.
290 */
291 list_for_each_safe(cur, tmp, &channel->sc_list) {
292 cur_sc = list_entry(cur, struct vmbus_channel,
293 sc_list);
294 if (cur_sc->offermsg.child_relid == relid) {
295 found_channel = cur_sc;
296 break;
297 }
298 }
299 }
300 }
301
302 return found_channel;
303}
304
305/*
306 * vmbus_on_event - Process a channel event notification
307 *
308 * For batched channels (default) optimize host to guest signaling
309 * by ensuring:
310 * 1. While reading the channel, we disable interrupts from host.
311 * 2. Ensure that we process all posted messages from the host
312 * before returning from this callback.
313 * 3. Once we return, enable signaling from the host. Once this
314 * state is set we check to see if additional packets are
315 * available to read. In this case we repeat the process.
316 * If this tasklet has been running for a long time
317 * then reschedule ourselves.
318 */
319void vmbus_on_event(unsigned long data)
320{
321 struct vmbus_channel *channel = (void *) data;
322 unsigned long time_limit = jiffies + 2;
323
324 trace_vmbus_on_event(channel);
325
326 do {
327 void (*callback_fn)(void *);
328
329 /* A channel once created is persistent even when
330 * there is no driver handling the device. An
331 * unloading driver sets the onchannel_callback to NULL.
332 */
333 callback_fn = READ_ONCE(channel->onchannel_callback);
334 if (unlikely(callback_fn == NULL))
335 return;
336
337 (*callback_fn)(channel->channel_callback_context);
338
339 if (channel->callback_mode != HV_CALL_BATCHED)
340 return;
341
342 if (likely(hv_end_read(&channel->inbound) == 0))
343 return;
344
345 hv_begin_read(&channel->inbound);
346 } while (likely(time_before(jiffies, time_limit)));
347
348 /* The time limit (2 jiffies) has been reached */
349 tasklet_schedule(&channel->callback_event);
350}
351
352/*
353 * vmbus_post_msg - Send a msg on the vmbus's message connection
354 */
355int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
356{
357 union hv_connection_id conn_id;
358 int ret = 0;
359 int retries = 0;
360 u32 usec = 1;
361
362 conn_id.asu32 = 0;
363 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
364
365 /*
366 * hv_post_message() can have transient failures because of
367 * insufficient resources. Retry the operation a couple of
368 * times before giving up.
369 */
370 while (retries < 100) {
371 ret = hv_post_message(conn_id, 1, buffer, buflen);
372
373 switch (ret) {
374 case HV_STATUS_INVALID_CONNECTION_ID:
375 /*
376 * We could get this if we send messages too
377 * frequently.
378 */
379 ret = -EAGAIN;
380 break;
381 case HV_STATUS_INSUFFICIENT_MEMORY:
382 case HV_STATUS_INSUFFICIENT_BUFFERS:
383 ret = -ENOBUFS;
384 break;
385 case HV_STATUS_SUCCESS:
386 return ret;
387 default:
388 pr_err("hv_post_msg() failed; error code:%d\n", ret);
389 return -EINVAL;
390 }
391
392 retries++;
393 if (can_sleep && usec > 1000)
394 msleep(usec / 1000);
395 else if (usec < MAX_UDELAY_MS * 1000)
396 udelay(usec);
397 else
398 mdelay(usec / 1000);
399
400 if (retries < 22)
401 usec *= 2;
402 }
403 return ret;
404}
405
406/*
407 * vmbus_set_event - Send an event notification to the parent
408 */
409void vmbus_set_event(struct vmbus_channel *channel)
410{
411 u32 child_relid = channel->offermsg.child_relid;
412
413 if (!channel->is_dedicated_interrupt)
414 vmbus_send_interrupt(child_relid);
415
416 ++channel->sig_events;
417
418 hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
419}
420EXPORT_SYMBOL_GPL(vmbus_set_event);