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/module.h>
18 #include <linux/slab.h>
19 #include <linux/vmalloc.h>
20 #include <linux/hyperv.h>
21 #include <linux/export.h>
22 #include <asm/mshyperv.h>
23
24 #include "hyperv_vmbus.h"
25
26
27 struct vmbus_connection vmbus_connection = {
28 .conn_state = DISCONNECTED,
29 .next_gpadl_handle = ATOMIC_INIT(0xE1E10),
30
31 .ready_for_suspend_event= COMPLETION_INITIALIZER(
32 vmbus_connection.ready_for_suspend_event),
33 .ready_for_resume_event = COMPLETION_INITIALIZER(
34 vmbus_connection.ready_for_resume_event),
35 };
36 EXPORT_SYMBOL_GPL(vmbus_connection);
37
38 /*
39 * Negotiated protocol version with the host.
40 */
41 __u32 vmbus_proto_version;
42 EXPORT_SYMBOL_GPL(vmbus_proto_version);
43
44 /*
45 * Table of VMBus versions listed from newest to oldest.
46 */
47 static __u32 vmbus_versions[] = {
48 VERSION_WIN10_V5_2,
49 VERSION_WIN10_V5_1,
50 VERSION_WIN10_V5,
51 VERSION_WIN10_V4_1,
52 VERSION_WIN10,
53 VERSION_WIN8_1,
54 VERSION_WIN8,
55 VERSION_WIN7,
56 VERSION_WS2008
57 };
58
59 /*
60 * Maximal VMBus protocol version guests can negotiate. Useful to cap the
61 * VMBus version for testing and debugging purpose.
62 */
63 static uint max_version = VERSION_WIN10_V5_2;
64
65 module_param(max_version, uint, S_IRUGO);
66 MODULE_PARM_DESC(max_version,
67 "Maximal VMBus protocol version which can be negotiated");
68
vmbus_negotiate_version(struct vmbus_channel_msginfo * msginfo,u32 version)69 int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
70 {
71 int ret = 0;
72 struct vmbus_channel_initiate_contact *msg;
73 unsigned long flags;
74
75 init_completion(&msginfo->waitevent);
76
77 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
78
79 memset(msg, 0, sizeof(*msg));
80 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
81 msg->vmbus_version_requested = version;
82
83 /*
84 * VMBus protocol 5.0 (VERSION_WIN10_V5) and higher require that we must
85 * use VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message,
86 * and for subsequent messages, we must use the Message Connection ID
87 * field in the host-returned Version Response Message. And, with
88 * VERSION_WIN10_V5 and higher, we don't use msg->interrupt_page, but we
89 * tell the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for
90 * compatibility.
91 *
92 * On old hosts, we should always use VMBUS_MESSAGE_CONNECTION_ID (1).
93 */
94 if (version >= VERSION_WIN10_V5) {
95 msg->msg_sint = VMBUS_MESSAGE_SINT;
96 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;
97 } else {
98 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
99 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID;
100 }
101
102 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
103 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
104 msg->target_vcpu = hv_cpu_number_to_vp_number(VMBUS_CONNECT_CPU);
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
141 if (version >= VERSION_WIN10_V5)
142 vmbus_connection.msg_conn_id =
143 msginfo->response.version_response.msg_conn_id;
144 } else {
145 return -ECONNREFUSED;
146 }
147
148 return ret;
149 }
150
151 /*
152 * vmbus_connect - Sends a connect request on the partition service connection
153 */
vmbus_connect(void)154 int vmbus_connect(void)
155 {
156 struct vmbus_channel_msginfo *msginfo = NULL;
157 int i, ret = 0;
158 __u32 version;
159
160 /* Initialize the vmbus connection */
161 vmbus_connection.conn_state = CONNECTING;
162 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
163 if (!vmbus_connection.work_queue) {
164 ret = -ENOMEM;
165 goto cleanup;
166 }
167
168 vmbus_connection.handle_primary_chan_wq =
169 create_workqueue("hv_pri_chan");
170 if (!vmbus_connection.handle_primary_chan_wq) {
171 ret = -ENOMEM;
172 goto cleanup;
173 }
174
175 vmbus_connection.handle_sub_chan_wq =
176 create_workqueue("hv_sub_chan");
177 if (!vmbus_connection.handle_sub_chan_wq) {
178 ret = -ENOMEM;
179 goto cleanup;
180 }
181
182 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
183 spin_lock_init(&vmbus_connection.channelmsg_lock);
184
185 INIT_LIST_HEAD(&vmbus_connection.chn_list);
186 mutex_init(&vmbus_connection.channel_mutex);
187
188 /*
189 * Setup the vmbus event connection for channel interrupt
190 * abstraction stuff
191 */
192 vmbus_connection.int_page =
193 (void *)hv_alloc_hyperv_zeroed_page();
194 if (vmbus_connection.int_page == NULL) {
195 ret = -ENOMEM;
196 goto cleanup;
197 }
198
199 vmbus_connection.recv_int_page = vmbus_connection.int_page;
200 vmbus_connection.send_int_page =
201 (void *)((unsigned long)vmbus_connection.int_page +
202 (HV_HYP_PAGE_SIZE >> 1));
203
204 /*
205 * Setup the monitor notification facility. The 1st page for
206 * parent->child and the 2nd page for child->parent
207 */
208 vmbus_connection.monitor_pages[0] = (void *)hv_alloc_hyperv_zeroed_page();
209 vmbus_connection.monitor_pages[1] = (void *)hv_alloc_hyperv_zeroed_page();
210 if ((vmbus_connection.monitor_pages[0] == NULL) ||
211 (vmbus_connection.monitor_pages[1] == NULL)) {
212 ret = -ENOMEM;
213 goto cleanup;
214 }
215
216 msginfo = kzalloc(sizeof(*msginfo) +
217 sizeof(struct vmbus_channel_initiate_contact),
218 GFP_KERNEL);
219 if (msginfo == NULL) {
220 ret = -ENOMEM;
221 goto cleanup;
222 }
223
224 /*
225 * Negotiate a compatible VMBUS version number with the
226 * host. We start with the highest number we can support
227 * and work our way down until we negotiate a compatible
228 * version.
229 */
230
231 for (i = 0; ; i++) {
232 if (i == ARRAY_SIZE(vmbus_versions)) {
233 ret = -EDOM;
234 goto cleanup;
235 }
236
237 version = vmbus_versions[i];
238 if (version > max_version)
239 continue;
240
241 ret = vmbus_negotiate_version(msginfo, version);
242 if (ret == -ETIMEDOUT)
243 goto cleanup;
244
245 if (vmbus_connection.conn_state == CONNECTED)
246 break;
247 }
248
249 vmbus_proto_version = version;
250 pr_info("Vmbus version:%d.%d\n",
251 version >> 16, version & 0xFFFF);
252
253 vmbus_connection.channels = kcalloc(MAX_CHANNEL_RELIDS,
254 sizeof(struct vmbus_channel *),
255 GFP_KERNEL);
256 if (vmbus_connection.channels == NULL) {
257 ret = -ENOMEM;
258 goto cleanup;
259 }
260
261 kfree(msginfo);
262 return 0;
263
264 cleanup:
265 pr_err("Unable to connect to host\n");
266
267 vmbus_connection.conn_state = DISCONNECTED;
268 vmbus_disconnect();
269
270 kfree(msginfo);
271
272 return ret;
273 }
274
vmbus_disconnect(void)275 void vmbus_disconnect(void)
276 {
277 /*
278 * First send the unload request to the host.
279 */
280 vmbus_initiate_unload(false);
281
282 if (vmbus_connection.handle_sub_chan_wq)
283 destroy_workqueue(vmbus_connection.handle_sub_chan_wq);
284
285 if (vmbus_connection.handle_primary_chan_wq)
286 destroy_workqueue(vmbus_connection.handle_primary_chan_wq);
287
288 if (vmbus_connection.work_queue)
289 destroy_workqueue(vmbus_connection.work_queue);
290
291 if (vmbus_connection.int_page) {
292 hv_free_hyperv_page((unsigned long)vmbus_connection.int_page);
293 vmbus_connection.int_page = NULL;
294 }
295
296 hv_free_hyperv_page((unsigned long)vmbus_connection.monitor_pages[0]);
297 hv_free_hyperv_page((unsigned long)vmbus_connection.monitor_pages[1]);
298 vmbus_connection.monitor_pages[0] = NULL;
299 vmbus_connection.monitor_pages[1] = NULL;
300 }
301
302 /*
303 * relid2channel - Get the channel object given its
304 * child relative id (ie channel id)
305 */
relid2channel(u32 relid)306 struct vmbus_channel *relid2channel(u32 relid)
307 {
308 if (vmbus_connection.channels == NULL) {
309 pr_warn_once("relid2channel: relid=%d: No channels mapped!\n", relid);
310 return NULL;
311 }
312 if (WARN_ON(relid >= MAX_CHANNEL_RELIDS))
313 return NULL;
314 return READ_ONCE(vmbus_connection.channels[relid]);
315 }
316
317 /*
318 * vmbus_on_event - Process a channel event notification
319 *
320 * For batched channels (default) optimize host to guest signaling
321 * by ensuring:
322 * 1. While reading the channel, we disable interrupts from host.
323 * 2. Ensure that we process all posted messages from the host
324 * before returning from this callback.
325 * 3. Once we return, enable signaling from the host. Once this
326 * state is set we check to see if additional packets are
327 * available to read. In this case we repeat the process.
328 * If this tasklet has been running for a long time
329 * then reschedule ourselves.
330 */
vmbus_on_event(unsigned long data)331 void vmbus_on_event(unsigned long data)
332 {
333 struct vmbus_channel *channel = (void *) data;
334 unsigned long time_limit = jiffies + 2;
335
336 trace_vmbus_on_event(channel);
337
338 hv_debug_delay_test(channel, INTERRUPT_DELAY);
339 do {
340 void (*callback_fn)(void *);
341
342 /* A channel once created is persistent even when
343 * there is no driver handling the device. An
344 * unloading driver sets the onchannel_callback to NULL.
345 */
346 callback_fn = READ_ONCE(channel->onchannel_callback);
347 if (unlikely(callback_fn == NULL))
348 return;
349
350 (*callback_fn)(channel->channel_callback_context);
351
352 if (channel->callback_mode != HV_CALL_BATCHED)
353 return;
354
355 if (likely(hv_end_read(&channel->inbound) == 0))
356 return;
357
358 hv_begin_read(&channel->inbound);
359 } while (likely(time_before(jiffies, time_limit)));
360
361 /* The time limit (2 jiffies) has been reached */
362 tasklet_schedule(&channel->callback_event);
363 }
364
365 /*
366 * vmbus_post_msg - Send a msg on the vmbus's message connection
367 */
vmbus_post_msg(void * buffer,size_t buflen,bool can_sleep)368 int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
369 {
370 struct vmbus_channel_message_header *hdr;
371 union hv_connection_id conn_id;
372 int ret = 0;
373 int retries = 0;
374 u32 usec = 1;
375
376 conn_id.asu32 = 0;
377 conn_id.u.id = vmbus_connection.msg_conn_id;
378
379 /*
380 * hv_post_message() can have transient failures because of
381 * insufficient resources. Retry the operation a couple of
382 * times before giving up.
383 */
384 while (retries < 100) {
385 ret = hv_post_message(conn_id, 1, buffer, buflen);
386
387 switch (ret) {
388 case HV_STATUS_INVALID_CONNECTION_ID:
389 /*
390 * See vmbus_negotiate_version(): VMBus protocol 5.0
391 * and higher require that we must use
392 * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate
393 * Contact message, but on old hosts that only
394 * support VMBus protocol 4.0 or lower, here we get
395 * HV_STATUS_INVALID_CONNECTION_ID and we should
396 * return an error immediately without retrying.
397 */
398 hdr = buffer;
399 if (hdr->msgtype == CHANNELMSG_INITIATE_CONTACT)
400 return -EINVAL;
401 /*
402 * We could get this if we send messages too
403 * frequently.
404 */
405 ret = -EAGAIN;
406 break;
407 case HV_STATUS_INSUFFICIENT_MEMORY:
408 case HV_STATUS_INSUFFICIENT_BUFFERS:
409 ret = -ENOBUFS;
410 break;
411 case HV_STATUS_SUCCESS:
412 return ret;
413 default:
414 pr_err("hv_post_msg() failed; error code:%d\n", ret);
415 return -EINVAL;
416 }
417
418 retries++;
419 if (can_sleep && usec > 1000)
420 msleep(usec / 1000);
421 else if (usec < MAX_UDELAY_MS * 1000)
422 udelay(usec);
423 else
424 mdelay(usec / 1000);
425
426 if (retries < 22)
427 usec *= 2;
428 }
429 return ret;
430 }
431
432 /*
433 * vmbus_set_event - Send an event notification to the parent
434 */
vmbus_set_event(struct vmbus_channel * channel)435 void vmbus_set_event(struct vmbus_channel *channel)
436 {
437 u32 child_relid = channel->offermsg.child_relid;
438
439 if (!channel->is_dedicated_interrupt)
440 vmbus_send_interrupt(child_relid);
441
442 ++channel->sig_events;
443
444 hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
445 }
446 EXPORT_SYMBOL_GPL(vmbus_set_event);
447