1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 *
4 * Copyright (c) 2009, Microsoft Corporation.
5 *
6 * Authors:
7 * Haiyang Zhang <haiyangz@microsoft.com>
8 * Hank Janssen <hjanssen@microsoft.com>
9 */
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12 #include <linux/kernel.h>
13 #include <linux/sched.h>
14 #include <linux/wait.h>
15 #include <linux/delay.h>
16 #include <linux/mm.h>
17 #include <linux/slab.h>
18 #include <linux/vmalloc.h>
19 #include <linux/hyperv.h>
20 #include <linux/export.h>
21 #include <asm/mshyperv.h>
22
23 #include "hyperv_vmbus.h"
24
25
26 struct vmbus_connection vmbus_connection = {
27 .conn_state = DISCONNECTED,
28 .next_gpadl_handle = ATOMIC_INIT(0xE1E10),
29
30 .ready_for_suspend_event= COMPLETION_INITIALIZER(
31 vmbus_connection.ready_for_suspend_event),
32 .ready_for_resume_event = COMPLETION_INITIALIZER(
33 vmbus_connection.ready_for_resume_event),
34 };
35 EXPORT_SYMBOL_GPL(vmbus_connection);
36
37 /*
38 * Negotiated protocol version with the host.
39 */
40 __u32 vmbus_proto_version;
41 EXPORT_SYMBOL_GPL(vmbus_proto_version);
42
vmbus_get_next_version(__u32 current_version)43 static __u32 vmbus_get_next_version(__u32 current_version)
44 {
45 switch (current_version) {
46 case (VERSION_WIN7):
47 return VERSION_WS2008;
48
49 case (VERSION_WIN8):
50 return VERSION_WIN7;
51
52 case (VERSION_WIN8_1):
53 return VERSION_WIN8;
54
55 case (VERSION_WIN10):
56 return VERSION_WIN8_1;
57
58 case (VERSION_WIN10_V5):
59 return VERSION_WIN10;
60
61 case (VERSION_WS2008):
62 default:
63 return VERSION_INVAL;
64 }
65 }
66
vmbus_negotiate_version(struct vmbus_channel_msginfo * msginfo,u32 version)67 int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
68 {
69 int ret = 0;
70 unsigned int cur_cpu;
71 struct vmbus_channel_initiate_contact *msg;
72 unsigned long flags;
73
74 init_completion(&msginfo->waitevent);
75
76 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
77
78 memset(msg, 0, sizeof(*msg));
79 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
80 msg->vmbus_version_requested = version;
81
82 /*
83 * VMBus protocol 5.0 (VERSION_WIN10_V5) requires that we must use
84 * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message,
85 * and for subsequent messages, we must use the Message Connection ID
86 * field in the host-returned Version Response Message. And, with
87 * VERSION_WIN10_V5, we don't use msg->interrupt_page, but we tell
88 * the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for
89 * compatibility.
90 *
91 * On old hosts, we should always use VMBUS_MESSAGE_CONNECTION_ID (1).
92 */
93 if (version >= VERSION_WIN10_V5) {
94 msg->msg_sint = VMBUS_MESSAGE_SINT;
95 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;
96 } else {
97 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
98 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID;
99 }
100
101 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
102 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
103 /*
104 * We want all channel messages to be delivered on CPU 0.
105 * This has been the behavior pre-win8. This is not
106 * perf issue and having all channel messages delivered on CPU 0
107 * would be ok.
108 * For post win8 hosts, we support receiving channel messagges on
109 * all the CPUs. This is needed for kexec to work correctly where
110 * the CPU attempting to connect may not be CPU 0.
111 */
112 if (version >= VERSION_WIN8_1) {
113 cur_cpu = get_cpu();
114 msg->target_vcpu = hv_cpu_number_to_vp_number(cur_cpu);
115 vmbus_connection.connect_cpu = cur_cpu;
116 put_cpu();
117 } else {
118 msg->target_vcpu = 0;
119 vmbus_connection.connect_cpu = 0;
120 }
121
122 /*
123 * Add to list before we send the request since we may
124 * receive the response before returning from this routine
125 */
126 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
127 list_add_tail(&msginfo->msglistentry,
128 &vmbus_connection.chn_msg_list);
129
130 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
131
132 ret = vmbus_post_msg(msg,
133 sizeof(struct vmbus_channel_initiate_contact),
134 true);
135
136 trace_vmbus_negotiate_version(msg, ret);
137
138 if (ret != 0) {
139 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
140 list_del(&msginfo->msglistentry);
141 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
142 flags);
143 return ret;
144 }
145
146 /* Wait for the connection response */
147 wait_for_completion(&msginfo->waitevent);
148
149 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
150 list_del(&msginfo->msglistentry);
151 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
152
153 /* Check if successful */
154 if (msginfo->response.version_response.version_supported) {
155 vmbus_connection.conn_state = CONNECTED;
156
157 if (version >= VERSION_WIN10_V5)
158 vmbus_connection.msg_conn_id =
159 msginfo->response.version_response.msg_conn_id;
160 } else {
161 return -ECONNREFUSED;
162 }
163
164 return ret;
165 }
166
167 /*
168 * vmbus_connect - Sends a connect request on the partition service connection
169 */
vmbus_connect(void)170 int vmbus_connect(void)
171 {
172 int ret = 0;
173 struct vmbus_channel_msginfo *msginfo = NULL;
174 __u32 version;
175
176 /* Initialize the vmbus connection */
177 vmbus_connection.conn_state = CONNECTING;
178 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
179 if (!vmbus_connection.work_queue) {
180 ret = -ENOMEM;
181 goto cleanup;
182 }
183
184 vmbus_connection.handle_primary_chan_wq =
185 create_workqueue("hv_pri_chan");
186 if (!vmbus_connection.handle_primary_chan_wq) {
187 ret = -ENOMEM;
188 goto cleanup;
189 }
190
191 vmbus_connection.handle_sub_chan_wq =
192 create_workqueue("hv_sub_chan");
193 if (!vmbus_connection.handle_sub_chan_wq) {
194 ret = -ENOMEM;
195 goto cleanup;
196 }
197
198 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
199 spin_lock_init(&vmbus_connection.channelmsg_lock);
200
201 INIT_LIST_HEAD(&vmbus_connection.chn_list);
202 mutex_init(&vmbus_connection.channel_mutex);
203
204 /*
205 * Setup the vmbus event connection for channel interrupt
206 * abstraction stuff
207 */
208 vmbus_connection.int_page =
209 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
210 if (vmbus_connection.int_page == NULL) {
211 ret = -ENOMEM;
212 goto cleanup;
213 }
214
215 vmbus_connection.recv_int_page = vmbus_connection.int_page;
216 vmbus_connection.send_int_page =
217 (void *)((unsigned long)vmbus_connection.int_page +
218 (PAGE_SIZE >> 1));
219
220 /*
221 * Setup the monitor notification facility. The 1st page for
222 * parent->child and the 2nd page for child->parent
223 */
224 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
225 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
226 if ((vmbus_connection.monitor_pages[0] == NULL) ||
227 (vmbus_connection.monitor_pages[1] == NULL)) {
228 ret = -ENOMEM;
229 goto cleanup;
230 }
231
232 msginfo = kzalloc(sizeof(*msginfo) +
233 sizeof(struct vmbus_channel_initiate_contact),
234 GFP_KERNEL);
235 if (msginfo == NULL) {
236 ret = -ENOMEM;
237 goto cleanup;
238 }
239
240 /*
241 * Negotiate a compatible VMBUS version number with the
242 * host. We start with the highest number we can support
243 * and work our way down until we negotiate a compatible
244 * version.
245 */
246
247 version = VERSION_CURRENT;
248
249 do {
250 ret = vmbus_negotiate_version(msginfo, version);
251 if (ret == -ETIMEDOUT)
252 goto cleanup;
253
254 if (vmbus_connection.conn_state == CONNECTED)
255 break;
256
257 version = vmbus_get_next_version(version);
258 } while (version != VERSION_INVAL);
259
260 if (version == VERSION_INVAL)
261 goto cleanup;
262
263 vmbus_proto_version = version;
264 pr_info("Vmbus version:%d.%d\n",
265 version >> 16, version & 0xFFFF);
266
267 kfree(msginfo);
268 return 0;
269
270 cleanup:
271 pr_err("Unable to connect to host\n");
272
273 vmbus_connection.conn_state = DISCONNECTED;
274 vmbus_disconnect();
275
276 kfree(msginfo);
277
278 return ret;
279 }
280
vmbus_disconnect(void)281 void vmbus_disconnect(void)
282 {
283 /*
284 * First send the unload request to the host.
285 */
286 vmbus_initiate_unload(false);
287
288 if (vmbus_connection.handle_sub_chan_wq)
289 destroy_workqueue(vmbus_connection.handle_sub_chan_wq);
290
291 if (vmbus_connection.handle_primary_chan_wq)
292 destroy_workqueue(vmbus_connection.handle_primary_chan_wq);
293
294 if (vmbus_connection.work_queue)
295 destroy_workqueue(vmbus_connection.work_queue);
296
297 if (vmbus_connection.int_page) {
298 free_pages((unsigned long)vmbus_connection.int_page, 0);
299 vmbus_connection.int_page = NULL;
300 }
301
302 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
303 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
304 vmbus_connection.monitor_pages[0] = NULL;
305 vmbus_connection.monitor_pages[1] = NULL;
306 }
307
308 /*
309 * relid2channel - Get the channel object given its
310 * child relative id (ie channel id)
311 */
relid2channel(u32 relid)312 struct vmbus_channel *relid2channel(u32 relid)
313 {
314 struct vmbus_channel *channel;
315 struct vmbus_channel *found_channel = NULL;
316 struct list_head *cur, *tmp;
317 struct vmbus_channel *cur_sc;
318
319 BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex));
320
321 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
322 if (channel->offermsg.child_relid == relid) {
323 found_channel = channel;
324 break;
325 } else if (!list_empty(&channel->sc_list)) {
326 /*
327 * Deal with sub-channels.
328 */
329 list_for_each_safe(cur, tmp, &channel->sc_list) {
330 cur_sc = list_entry(cur, struct vmbus_channel,
331 sc_list);
332 if (cur_sc->offermsg.child_relid == relid) {
333 found_channel = cur_sc;
334 break;
335 }
336 }
337 }
338 }
339
340 return found_channel;
341 }
342
343 /*
344 * vmbus_on_event - Process a channel event notification
345 *
346 * For batched channels (default) optimize host to guest signaling
347 * by ensuring:
348 * 1. While reading the channel, we disable interrupts from host.
349 * 2. Ensure that we process all posted messages from the host
350 * before returning from this callback.
351 * 3. Once we return, enable signaling from the host. Once this
352 * state is set we check to see if additional packets are
353 * available to read. In this case we repeat the process.
354 * If this tasklet has been running for a long time
355 * then reschedule ourselves.
356 */
vmbus_on_event(unsigned long data)357 void vmbus_on_event(unsigned long data)
358 {
359 struct vmbus_channel *channel = (void *) data;
360 unsigned long time_limit = jiffies + 2;
361
362 trace_vmbus_on_event(channel);
363
364 do {
365 void (*callback_fn)(void *);
366
367 /* A channel once created is persistent even when
368 * there is no driver handling the device. An
369 * unloading driver sets the onchannel_callback to NULL.
370 */
371 callback_fn = READ_ONCE(channel->onchannel_callback);
372 if (unlikely(callback_fn == NULL))
373 return;
374
375 (*callback_fn)(channel->channel_callback_context);
376
377 if (channel->callback_mode != HV_CALL_BATCHED)
378 return;
379
380 if (likely(hv_end_read(&channel->inbound) == 0))
381 return;
382
383 hv_begin_read(&channel->inbound);
384 } while (likely(time_before(jiffies, time_limit)));
385
386 /* The time limit (2 jiffies) has been reached */
387 tasklet_schedule(&channel->callback_event);
388 }
389
390 /*
391 * vmbus_post_msg - Send a msg on the vmbus's message connection
392 */
vmbus_post_msg(void * buffer,size_t buflen,bool can_sleep)393 int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
394 {
395 struct vmbus_channel_message_header *hdr;
396 union hv_connection_id conn_id;
397 int ret = 0;
398 int retries = 0;
399 u32 usec = 1;
400
401 conn_id.asu32 = 0;
402 conn_id.u.id = vmbus_connection.msg_conn_id;
403
404 /*
405 * hv_post_message() can have transient failures because of
406 * insufficient resources. Retry the operation a couple of
407 * times before giving up.
408 */
409 while (retries < 100) {
410 ret = hv_post_message(conn_id, 1, buffer, buflen);
411
412 switch (ret) {
413 case HV_STATUS_INVALID_CONNECTION_ID:
414 /*
415 * See vmbus_negotiate_version(): VMBus protocol 5.0
416 * requires that we must use
417 * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate
418 * Contact message, but on old hosts that only
419 * support VMBus protocol 4.0 or lower, here we get
420 * HV_STATUS_INVALID_CONNECTION_ID and we should
421 * return an error immediately without retrying.
422 */
423 hdr = buffer;
424 if (hdr->msgtype == CHANNELMSG_INITIATE_CONTACT)
425 return -EINVAL;
426 /*
427 * We could get this if we send messages too
428 * frequently.
429 */
430 ret = -EAGAIN;
431 break;
432 case HV_STATUS_INSUFFICIENT_MEMORY:
433 case HV_STATUS_INSUFFICIENT_BUFFERS:
434 ret = -ENOBUFS;
435 break;
436 case HV_STATUS_SUCCESS:
437 return ret;
438 default:
439 pr_err("hv_post_msg() failed; error code:%d\n", ret);
440 return -EINVAL;
441 }
442
443 retries++;
444 if (can_sleep && usec > 1000)
445 msleep(usec / 1000);
446 else if (usec < MAX_UDELAY_MS * 1000)
447 udelay(usec);
448 else
449 mdelay(usec / 1000);
450
451 if (retries < 22)
452 usec *= 2;
453 }
454 return ret;
455 }
456
457 /*
458 * vmbus_set_event - Send an event notification to the parent
459 */
vmbus_set_event(struct vmbus_channel * channel)460 void vmbus_set_event(struct vmbus_channel *channel)
461 {
462 u32 child_relid = channel->offermsg.child_relid;
463
464 if (!channel->is_dedicated_interrupt)
465 vmbus_send_interrupt(child_relid);
466
467 ++channel->sig_events;
468
469 hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
470 }
471 EXPORT_SYMBOL_GPL(vmbus_set_event);
472
