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/hyperv.h>
35 #include <asm/mshyperv.h>
36
37 #include "hyperv_vmbus.h"
38
39
40 struct vmbus_connection vmbus_connection = {
41 .conn_state = DISCONNECTED,
42 .next_gpadl_handle = ATOMIC_INIT(0xE1E10),
43 };
44 EXPORT_SYMBOL_GPL(vmbus_connection);
45
46 /*
47 * Negotiated protocol version with the host.
48 */
49 __u32 vmbus_proto_version;
50 EXPORT_SYMBOL_GPL(vmbus_proto_version);
51
vmbus_get_next_version(__u32 current_version)52 static __u32 vmbus_get_next_version(__u32 current_version)
53 {
54 switch (current_version) {
55 case (VERSION_WIN7):
56 return VERSION_WS2008;
57
58 case (VERSION_WIN8):
59 return VERSION_WIN7;
60
61 case (VERSION_WIN8_1):
62 return VERSION_WIN8;
63
64 case (VERSION_WIN10):
65 return VERSION_WIN8_1;
66
67 case (VERSION_WS2008):
68 default:
69 return VERSION_INVAL;
70 }
71 }
72
vmbus_negotiate_version(struct vmbus_channel_msginfo * msginfo,__u32 version)73 static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
74 __u32 version)
75 {
76 int ret = 0;
77 unsigned int cur_cpu;
78 struct vmbus_channel_initiate_contact *msg;
79 unsigned long flags;
80
81 init_completion(&msginfo->waitevent);
82
83 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
84
85 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
86 msg->vmbus_version_requested = version;
87 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
88 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
89 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
90 /*
91 * We want all channel messages to be delivered on CPU 0.
92 * This has been the behavior pre-win8. This is not
93 * perf issue and having all channel messages delivered on CPU 0
94 * would be ok.
95 * For post win8 hosts, we support receiving channel messagges on
96 * all the CPUs. This is needed for kexec to work correctly where
97 * the CPU attempting to connect may not be CPU 0.
98 */
99 if (version >= VERSION_WIN8_1) {
100 cur_cpu = get_cpu();
101 msg->target_vcpu = hv_cpu_number_to_vp_number(cur_cpu);
102 vmbus_connection.connect_cpu = cur_cpu;
103 put_cpu();
104 } else {
105 msg->target_vcpu = 0;
106 vmbus_connection.connect_cpu = 0;
107 }
108
109 /*
110 * Add to list before we send the request since we may
111 * receive the response before returning from this routine
112 */
113 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
114 list_add_tail(&msginfo->msglistentry,
115 &vmbus_connection.chn_msg_list);
116
117 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
118
119 ret = vmbus_post_msg(msg,
120 sizeof(struct vmbus_channel_initiate_contact),
121 true);
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 */
vmbus_connect(void)150 int 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 vmbus_connection.handle_primary_chan_wq =
165 create_workqueue("hv_pri_chan");
166 if (!vmbus_connection.handle_primary_chan_wq) {
167 ret = -ENOMEM;
168 goto cleanup;
169 }
170
171 vmbus_connection.handle_sub_chan_wq =
172 create_workqueue("hv_sub_chan");
173 if (!vmbus_connection.handle_sub_chan_wq) {
174 ret = -ENOMEM;
175 goto cleanup;
176 }
177
178 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
179 spin_lock_init(&vmbus_connection.channelmsg_lock);
180
181 INIT_LIST_HEAD(&vmbus_connection.chn_list);
182 mutex_init(&vmbus_connection.channel_mutex);
183
184 /*
185 * Setup the vmbus event connection for channel interrupt
186 * abstraction stuff
187 */
188 vmbus_connection.int_page =
189 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
190 if (vmbus_connection.int_page == NULL) {
191 ret = -ENOMEM;
192 goto cleanup;
193 }
194
195 vmbus_connection.recv_int_page = vmbus_connection.int_page;
196 vmbus_connection.send_int_page =
197 (void *)((unsigned long)vmbus_connection.int_page +
198 (PAGE_SIZE >> 1));
199
200 /*
201 * Setup the monitor notification facility. The 1st page for
202 * parent->child and the 2nd page for child->parent
203 */
204 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
205 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
206 if ((vmbus_connection.monitor_pages[0] == NULL) ||
207 (vmbus_connection.monitor_pages[1] == NULL)) {
208 ret = -ENOMEM;
209 goto cleanup;
210 }
211
212 msginfo = kzalloc(sizeof(*msginfo) +
213 sizeof(struct vmbus_channel_initiate_contact),
214 GFP_KERNEL);
215 if (msginfo == NULL) {
216 ret = -ENOMEM;
217 goto cleanup;
218 }
219
220 /*
221 * Negotiate a compatible VMBUS version number with the
222 * host. We start with the highest number we can support
223 * and work our way down until we negotiate a compatible
224 * version.
225 */
226
227 version = VERSION_CURRENT;
228
229 do {
230 ret = vmbus_negotiate_version(msginfo, version);
231 if (ret == -ETIMEDOUT)
232 goto cleanup;
233
234 if (vmbus_connection.conn_state == CONNECTED)
235 break;
236
237 version = vmbus_get_next_version(version);
238 } while (version != VERSION_INVAL);
239
240 if (version == VERSION_INVAL)
241 goto cleanup;
242
243 vmbus_proto_version = version;
244 pr_info("Vmbus version:%d.%d\n",
245 version >> 16, version & 0xFFFF);
246
247 kfree(msginfo);
248 return 0;
249
250 cleanup:
251 pr_err("Unable to connect to host\n");
252
253 vmbus_connection.conn_state = DISCONNECTED;
254 vmbus_disconnect();
255
256 kfree(msginfo);
257
258 return ret;
259 }
260
vmbus_disconnect(void)261 void vmbus_disconnect(void)
262 {
263 /*
264 * First send the unload request to the host.
265 */
266 vmbus_initiate_unload(false);
267
268 if (vmbus_connection.handle_sub_chan_wq)
269 destroy_workqueue(vmbus_connection.handle_sub_chan_wq);
270
271 if (vmbus_connection.handle_primary_chan_wq)
272 destroy_workqueue(vmbus_connection.handle_primary_chan_wq);
273
274 if (vmbus_connection.work_queue)
275 destroy_workqueue(vmbus_connection.work_queue);
276
277 if (vmbus_connection.int_page) {
278 free_pages((unsigned long)vmbus_connection.int_page, 0);
279 vmbus_connection.int_page = NULL;
280 }
281
282 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
283 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
284 vmbus_connection.monitor_pages[0] = NULL;
285 vmbus_connection.monitor_pages[1] = NULL;
286 }
287
288 /*
289 * relid2channel - Get the channel object given its
290 * child relative id (ie channel id)
291 */
relid2channel(u32 relid)292 struct vmbus_channel *relid2channel(u32 relid)
293 {
294 struct vmbus_channel *channel;
295 struct vmbus_channel *found_channel = NULL;
296 struct list_head *cur, *tmp;
297 struct vmbus_channel *cur_sc;
298
299 BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex));
300
301 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
302 if (channel->offermsg.child_relid == relid) {
303 found_channel = channel;
304 break;
305 } else if (!list_empty(&channel->sc_list)) {
306 /*
307 * Deal with sub-channels.
308 */
309 list_for_each_safe(cur, tmp, &channel->sc_list) {
310 cur_sc = list_entry(cur, struct vmbus_channel,
311 sc_list);
312 if (cur_sc->offermsg.child_relid == relid) {
313 found_channel = cur_sc;
314 break;
315 }
316 }
317 }
318 }
319
320 return found_channel;
321 }
322
323 /*
324 * vmbus_on_event - Process a channel event notification
325 *
326 * For batched channels (default) optimize host to guest signaling
327 * by ensuring:
328 * 1. While reading the channel, we disable interrupts from host.
329 * 2. Ensure that we process all posted messages from the host
330 * before returning from this callback.
331 * 3. Once we return, enable signaling from the host. Once this
332 * state is set we check to see if additional packets are
333 * available to read. In this case we repeat the process.
334 * If this tasklet has been running for a long time
335 * then reschedule ourselves.
336 */
vmbus_on_event(unsigned long data)337 void vmbus_on_event(unsigned long data)
338 {
339 struct vmbus_channel *channel = (void *) data;
340 unsigned long time_limit = jiffies + 2;
341
342 do {
343 void (*callback_fn)(void *);
344
345 /* A channel once created is persistent even when
346 * there is no driver handling the device. An
347 * unloading driver sets the onchannel_callback to NULL.
348 */
349 callback_fn = READ_ONCE(channel->onchannel_callback);
350 if (unlikely(callback_fn == NULL))
351 return;
352
353 (*callback_fn)(channel->channel_callback_context);
354
355 if (channel->callback_mode != HV_CALL_BATCHED)
356 return;
357
358 if (likely(hv_end_read(&channel->inbound) == 0))
359 return;
360
361 hv_begin_read(&channel->inbound);
362 } while (likely(time_before(jiffies, time_limit)));
363
364 /* The time limit (2 jiffies) has been reached */
365 tasklet_schedule(&channel->callback_event);
366 }
367
368 /*
369 * vmbus_post_msg - Send a msg on the vmbus's message connection
370 */
vmbus_post_msg(void * buffer,size_t buflen,bool can_sleep)371 int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
372 {
373 union hv_connection_id conn_id;
374 int ret = 0;
375 int retries = 0;
376 u32 usec = 1;
377
378 conn_id.asu32 = 0;
379 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
380
381 /*
382 * hv_post_message() can have transient failures because of
383 * insufficient resources. Retry the operation a couple of
384 * times before giving up.
385 */
386 while (retries < 100) {
387 ret = hv_post_message(conn_id, 1, buffer, buflen);
388
389 switch (ret) {
390 case HV_STATUS_INVALID_CONNECTION_ID:
391 /*
392 * We could get this if we send messages too
393 * frequently.
394 */
395 ret = -EAGAIN;
396 break;
397 case HV_STATUS_INSUFFICIENT_MEMORY:
398 case HV_STATUS_INSUFFICIENT_BUFFERS:
399 ret = -ENOBUFS;
400 break;
401 case HV_STATUS_SUCCESS:
402 return ret;
403 default:
404 pr_err("hv_post_msg() failed; error code:%d\n", ret);
405 return -EINVAL;
406 }
407
408 retries++;
409 if (can_sleep && usec > 1000)
410 msleep(usec / 1000);
411 else if (usec < MAX_UDELAY_MS * 1000)
412 udelay(usec);
413 else
414 mdelay(usec / 1000);
415
416 if (retries < 22)
417 usec *= 2;
418 }
419 return ret;
420 }
421
422 /*
423 * vmbus_set_event - Send an event notification to the parent
424 */
vmbus_set_event(struct vmbus_channel * channel)425 void vmbus_set_event(struct vmbus_channel *channel)
426 {
427 u32 child_relid = channel->offermsg.child_relid;
428
429 if (!channel->is_dedicated_interrupt)
430 vmbus_send_interrupt(child_relid);
431
432 hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
433 }
434 EXPORT_SYMBOL_GPL(vmbus_set_event);
435