Loading...
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
26struct 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};
35EXPORT_SYMBOL_GPL(vmbus_connection);
36
37/*
38 * Negotiated protocol version with the host.
39 */
40__u32 vmbus_proto_version;
41EXPORT_SYMBOL_GPL(vmbus_proto_version);
42
43static __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
67int 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 */
170int 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
270cleanup:
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
281void 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 */
312struct 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 */
357void 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 */
393int 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 */
460void 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}
471EXPORT_SYMBOL_GPL(vmbus_set_event);
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
27struct 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};
36EXPORT_SYMBOL_GPL(vmbus_connection);
37
38/*
39 * Negotiated protocol version with the host.
40 */
41__u32 vmbus_proto_version;
42EXPORT_SYMBOL_GPL(vmbus_proto_version);
43
44/*
45 * Table of VMBus versions listed from newest to oldest.
46 */
47static __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 */
63static uint max_version = VERSION_WIN10_V5_2;
64
65module_param(max_version, uint, S_IRUGO);
66MODULE_PARM_DESC(max_version,
67 "Maximal VMBus protocol version which can be negotiated");
68
69int 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 */
154int 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 goto cleanup;
234
235 version = vmbus_versions[i];
236 if (version > max_version)
237 continue;
238
239 ret = vmbus_negotiate_version(msginfo, version);
240 if (ret == -ETIMEDOUT)
241 goto cleanup;
242
243 if (vmbus_connection.conn_state == CONNECTED)
244 break;
245 }
246
247 vmbus_proto_version = version;
248 pr_info("Vmbus version:%d.%d\n",
249 version >> 16, version & 0xFFFF);
250
251 vmbus_connection.channels = kcalloc(MAX_CHANNEL_RELIDS,
252 sizeof(struct vmbus_channel *),
253 GFP_KERNEL);
254 if (vmbus_connection.channels == NULL) {
255 ret = -ENOMEM;
256 goto cleanup;
257 }
258
259 kfree(msginfo);
260 return 0;
261
262cleanup:
263 pr_err("Unable to connect to host\n");
264
265 vmbus_connection.conn_state = DISCONNECTED;
266 vmbus_disconnect();
267
268 kfree(msginfo);
269
270 return ret;
271}
272
273void vmbus_disconnect(void)
274{
275 /*
276 * First send the unload request to the host.
277 */
278 vmbus_initiate_unload(false);
279
280 if (vmbus_connection.handle_sub_chan_wq)
281 destroy_workqueue(vmbus_connection.handle_sub_chan_wq);
282
283 if (vmbus_connection.handle_primary_chan_wq)
284 destroy_workqueue(vmbus_connection.handle_primary_chan_wq);
285
286 if (vmbus_connection.work_queue)
287 destroy_workqueue(vmbus_connection.work_queue);
288
289 if (vmbus_connection.int_page) {
290 hv_free_hyperv_page((unsigned long)vmbus_connection.int_page);
291 vmbus_connection.int_page = NULL;
292 }
293
294 hv_free_hyperv_page((unsigned long)vmbus_connection.monitor_pages[0]);
295 hv_free_hyperv_page((unsigned long)vmbus_connection.monitor_pages[1]);
296 vmbus_connection.monitor_pages[0] = NULL;
297 vmbus_connection.monitor_pages[1] = NULL;
298}
299
300/*
301 * relid2channel - Get the channel object given its
302 * child relative id (ie channel id)
303 */
304struct vmbus_channel *relid2channel(u32 relid)
305{
306 if (WARN_ON(relid >= MAX_CHANNEL_RELIDS))
307 return NULL;
308 return READ_ONCE(vmbus_connection.channels[relid]);
309}
310
311/*
312 * vmbus_on_event - Process a channel event notification
313 *
314 * For batched channels (default) optimize host to guest signaling
315 * by ensuring:
316 * 1. While reading the channel, we disable interrupts from host.
317 * 2. Ensure that we process all posted messages from the host
318 * before returning from this callback.
319 * 3. Once we return, enable signaling from the host. Once this
320 * state is set we check to see if additional packets are
321 * available to read. In this case we repeat the process.
322 * If this tasklet has been running for a long time
323 * then reschedule ourselves.
324 */
325void vmbus_on_event(unsigned long data)
326{
327 struct vmbus_channel *channel = (void *) data;
328 unsigned long time_limit = jiffies + 2;
329
330 trace_vmbus_on_event(channel);
331
332 hv_debug_delay_test(channel, INTERRUPT_DELAY);
333 do {
334 void (*callback_fn)(void *);
335
336 /* A channel once created is persistent even when
337 * there is no driver handling the device. An
338 * unloading driver sets the onchannel_callback to NULL.
339 */
340 callback_fn = READ_ONCE(channel->onchannel_callback);
341 if (unlikely(callback_fn == NULL))
342 return;
343
344 (*callback_fn)(channel->channel_callback_context);
345
346 if (channel->callback_mode != HV_CALL_BATCHED)
347 return;
348
349 if (likely(hv_end_read(&channel->inbound) == 0))
350 return;
351
352 hv_begin_read(&channel->inbound);
353 } while (likely(time_before(jiffies, time_limit)));
354
355 /* The time limit (2 jiffies) has been reached */
356 tasklet_schedule(&channel->callback_event);
357}
358
359/*
360 * vmbus_post_msg - Send a msg on the vmbus's message connection
361 */
362int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
363{
364 struct vmbus_channel_message_header *hdr;
365 union hv_connection_id conn_id;
366 int ret = 0;
367 int retries = 0;
368 u32 usec = 1;
369
370 conn_id.asu32 = 0;
371 conn_id.u.id = vmbus_connection.msg_conn_id;
372
373 /*
374 * hv_post_message() can have transient failures because of
375 * insufficient resources. Retry the operation a couple of
376 * times before giving up.
377 */
378 while (retries < 100) {
379 ret = hv_post_message(conn_id, 1, buffer, buflen);
380
381 switch (ret) {
382 case HV_STATUS_INVALID_CONNECTION_ID:
383 /*
384 * See vmbus_negotiate_version(): VMBus protocol 5.0
385 * and higher require that we must use
386 * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate
387 * Contact message, but on old hosts that only
388 * support VMBus protocol 4.0 or lower, here we get
389 * HV_STATUS_INVALID_CONNECTION_ID and we should
390 * return an error immediately without retrying.
391 */
392 hdr = buffer;
393 if (hdr->msgtype == CHANNELMSG_INITIATE_CONTACT)
394 return -EINVAL;
395 /*
396 * We could get this if we send messages too
397 * frequently.
398 */
399 ret = -EAGAIN;
400 break;
401 case HV_STATUS_INSUFFICIENT_MEMORY:
402 case HV_STATUS_INSUFFICIENT_BUFFERS:
403 ret = -ENOBUFS;
404 break;
405 case HV_STATUS_SUCCESS:
406 return ret;
407 default:
408 pr_err("hv_post_msg() failed; error code:%d\n", ret);
409 return -EINVAL;
410 }
411
412 retries++;
413 if (can_sleep && usec > 1000)
414 msleep(usec / 1000);
415 else if (usec < MAX_UDELAY_MS * 1000)
416 udelay(usec);
417 else
418 mdelay(usec / 1000);
419
420 if (retries < 22)
421 usec *= 2;
422 }
423 return ret;
424}
425
426/*
427 * vmbus_set_event - Send an event notification to the parent
428 */
429void vmbus_set_event(struct vmbus_channel *channel)
430{
431 u32 child_relid = channel->offermsg.child_relid;
432
433 if (!channel->is_dedicated_interrupt)
434 vmbus_send_interrupt(child_relid);
435
436 ++channel->sig_events;
437
438 hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
439}
440EXPORT_SYMBOL_GPL(vmbus_set_event);