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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 <linux/io.h>
23#include <linux/set_memory.h>
24#include <asm/mshyperv.h>
25
26#include "hyperv_vmbus.h"
27
28
29struct vmbus_connection vmbus_connection = {
30 .conn_state = DISCONNECTED,
31 .unload_event = COMPLETION_INITIALIZER(
32 vmbus_connection.unload_event),
33 .next_gpadl_handle = ATOMIC_INIT(0xE1E10),
34
35 .ready_for_suspend_event = COMPLETION_INITIALIZER(
36 vmbus_connection.ready_for_suspend_event),
37 .ready_for_resume_event = COMPLETION_INITIALIZER(
38 vmbus_connection.ready_for_resume_event),
39};
40EXPORT_SYMBOL_GPL(vmbus_connection);
41
42/*
43 * Negotiated protocol version with the host.
44 */
45__u32 vmbus_proto_version;
46EXPORT_SYMBOL_GPL(vmbus_proto_version);
47
48/*
49 * Table of VMBus versions listed from newest to oldest.
50 * VERSION_WIN7 and VERSION_WS2008 are no longer supported in
51 * Linux guests and are not listed.
52 */
53static __u32 vmbus_versions[] = {
54 VERSION_WIN10_V5_3,
55 VERSION_WIN10_V5_2,
56 VERSION_WIN10_V5_1,
57 VERSION_WIN10_V5,
58 VERSION_WIN10_V4_1,
59 VERSION_WIN10,
60 VERSION_WIN8_1,
61 VERSION_WIN8
62};
63
64/*
65 * Maximal VMBus protocol version guests can negotiate. Useful to cap the
66 * VMBus version for testing and debugging purpose.
67 */
68static uint max_version = VERSION_WIN10_V5_3;
69
70module_param(max_version, uint, S_IRUGO);
71MODULE_PARM_DESC(max_version,
72 "Maximal VMBus protocol version which can be negotiated");
73
74int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
75{
76 int ret = 0;
77 struct vmbus_channel_initiate_contact *msg;
78 unsigned long flags;
79
80 init_completion(&msginfo->waitevent);
81
82 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
83
84 memset(msg, 0, sizeof(*msg));
85 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
86 msg->vmbus_version_requested = version;
87
88 /*
89 * VMBus protocol 5.0 (VERSION_WIN10_V5) and higher require that we must
90 * use VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message,
91 * and for subsequent messages, we must use the Message Connection ID
92 * field in the host-returned Version Response Message. And, with
93 * VERSION_WIN10_V5 and higher, we don't use msg->interrupt_page, but we
94 * tell the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for
95 * compatibility.
96 *
97 * On old hosts, we should always use VMBUS_MESSAGE_CONNECTION_ID (1).
98 */
99 if (version >= VERSION_WIN10_V5) {
100 msg->msg_sint = VMBUS_MESSAGE_SINT;
101 msg->msg_vtl = ms_hyperv.vtl;
102 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4;
103 } else {
104 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
105 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID;
106 }
107
108 /*
109 * shared_gpa_boundary is zero in non-SNP VMs, so it's safe to always
110 * bitwise OR it
111 */
112 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]) |
113 ms_hyperv.shared_gpa_boundary;
114 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]) |
115 ms_hyperv.shared_gpa_boundary;
116
117 msg->target_vcpu = hv_cpu_number_to_vp_number(VMBUS_CONNECT_CPU);
118
119 /*
120 * Add to list before we send the request since we may
121 * receive the response before returning from this routine
122 */
123 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
124 list_add_tail(&msginfo->msglistentry,
125 &vmbus_connection.chn_msg_list);
126
127 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
128
129 ret = vmbus_post_msg(msg,
130 sizeof(struct vmbus_channel_initiate_contact),
131 true);
132
133 trace_vmbus_negotiate_version(msg, ret);
134
135 if (ret != 0) {
136 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
137 list_del(&msginfo->msglistentry);
138 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
139 flags);
140 return ret;
141 }
142
143 /* Wait for the connection response */
144 wait_for_completion(&msginfo->waitevent);
145
146 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
147 list_del(&msginfo->msglistentry);
148 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
149
150 /* Check if successful */
151 if (msginfo->response.version_response.version_supported) {
152 vmbus_connection.conn_state = CONNECTED;
153
154 if (version >= VERSION_WIN10_V5)
155 vmbus_connection.msg_conn_id =
156 msginfo->response.version_response.msg_conn_id;
157 } else {
158 return -ECONNREFUSED;
159 }
160
161 return ret;
162}
163
164/*
165 * vmbus_connect - Sends a connect request on the partition service connection
166 */
167int vmbus_connect(void)
168{
169 struct vmbus_channel_msginfo *msginfo = NULL;
170 int i, ret = 0;
171 __u32 version;
172
173 /* Initialize the vmbus connection */
174 vmbus_connection.conn_state = CONNECTING;
175 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
176 if (!vmbus_connection.work_queue) {
177 ret = -ENOMEM;
178 goto cleanup;
179 }
180
181 vmbus_connection.rescind_work_queue =
182 create_workqueue("hv_vmbus_rescind");
183 if (!vmbus_connection.rescind_work_queue) {
184 ret = -ENOMEM;
185 goto cleanup;
186 }
187 vmbus_connection.ignore_any_offer_msg = false;
188
189 vmbus_connection.handle_primary_chan_wq =
190 create_workqueue("hv_pri_chan");
191 if (!vmbus_connection.handle_primary_chan_wq) {
192 ret = -ENOMEM;
193 goto cleanup;
194 }
195
196 vmbus_connection.handle_sub_chan_wq =
197 create_workqueue("hv_sub_chan");
198 if (!vmbus_connection.handle_sub_chan_wq) {
199 ret = -ENOMEM;
200 goto cleanup;
201 }
202
203 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
204 spin_lock_init(&vmbus_connection.channelmsg_lock);
205
206 INIT_LIST_HEAD(&vmbus_connection.chn_list);
207 mutex_init(&vmbus_connection.channel_mutex);
208
209 /*
210 * Setup the vmbus event connection for channel interrupt
211 * abstraction stuff
212 */
213 vmbus_connection.int_page = hv_alloc_hyperv_zeroed_page();
214 if (vmbus_connection.int_page == NULL) {
215 ret = -ENOMEM;
216 goto cleanup;
217 }
218
219 vmbus_connection.recv_int_page = vmbus_connection.int_page;
220 vmbus_connection.send_int_page =
221 (void *)((unsigned long)vmbus_connection.int_page +
222 (HV_HYP_PAGE_SIZE >> 1));
223
224 /*
225 * Setup the monitor notification facility. The 1st page for
226 * parent->child and the 2nd page for child->parent
227 */
228 vmbus_connection.monitor_pages[0] = hv_alloc_hyperv_page();
229 vmbus_connection.monitor_pages[1] = hv_alloc_hyperv_page();
230 if ((vmbus_connection.monitor_pages[0] == NULL) ||
231 (vmbus_connection.monitor_pages[1] == NULL)) {
232 ret = -ENOMEM;
233 goto cleanup;
234 }
235
236 ret = set_memory_decrypted((unsigned long)
237 vmbus_connection.monitor_pages[0], 1);
238 ret |= set_memory_decrypted((unsigned long)
239 vmbus_connection.monitor_pages[1], 1);
240 if (ret)
241 goto cleanup;
242
243 /*
244 * Set_memory_decrypted() will change the memory contents if
245 * decryption occurs, so zero monitor pages here.
246 */
247 memset(vmbus_connection.monitor_pages[0], 0x00, HV_HYP_PAGE_SIZE);
248 memset(vmbus_connection.monitor_pages[1], 0x00, HV_HYP_PAGE_SIZE);
249
250 msginfo = kzalloc(sizeof(*msginfo) +
251 sizeof(struct vmbus_channel_initiate_contact),
252 GFP_KERNEL);
253 if (msginfo == NULL) {
254 ret = -ENOMEM;
255 goto cleanup;
256 }
257
258 /*
259 * Negotiate a compatible VMBUS version number with the
260 * host. We start with the highest number we can support
261 * and work our way down until we negotiate a compatible
262 * version.
263 */
264
265 for (i = 0; ; i++) {
266 if (i == ARRAY_SIZE(vmbus_versions)) {
267 ret = -EDOM;
268 goto cleanup;
269 }
270
271 version = vmbus_versions[i];
272 if (version > max_version)
273 continue;
274
275 ret = vmbus_negotiate_version(msginfo, version);
276 if (ret == -ETIMEDOUT)
277 goto cleanup;
278
279 if (vmbus_connection.conn_state == CONNECTED)
280 break;
281 }
282
283 if (hv_is_isolation_supported() && version < VERSION_WIN10_V5_2) {
284 pr_err("Invalid VMBus version %d.%d (expected >= %d.%d) from the host supporting isolation\n",
285 version >> 16, version & 0xFFFF, VERSION_WIN10_V5_2 >> 16, VERSION_WIN10_V5_2 & 0xFFFF);
286 ret = -EINVAL;
287 goto cleanup;
288 }
289
290 vmbus_proto_version = version;
291 pr_info("Vmbus version:%d.%d\n",
292 version >> 16, version & 0xFFFF);
293
294 vmbus_connection.channels = kcalloc(MAX_CHANNEL_RELIDS,
295 sizeof(struct vmbus_channel *),
296 GFP_KERNEL);
297 if (vmbus_connection.channels == NULL) {
298 ret = -ENOMEM;
299 goto cleanup;
300 }
301
302 kfree(msginfo);
303 return 0;
304
305cleanup:
306 pr_err("Unable to connect to host\n");
307
308 vmbus_connection.conn_state = DISCONNECTED;
309 vmbus_disconnect();
310
311 kfree(msginfo);
312
313 return ret;
314}
315
316void vmbus_disconnect(void)
317{
318 /*
319 * First send the unload request to the host.
320 */
321 vmbus_initiate_unload(false);
322
323 if (vmbus_connection.handle_sub_chan_wq)
324 destroy_workqueue(vmbus_connection.handle_sub_chan_wq);
325
326 if (vmbus_connection.handle_primary_chan_wq)
327 destroy_workqueue(vmbus_connection.handle_primary_chan_wq);
328
329 if (vmbus_connection.rescind_work_queue)
330 destroy_workqueue(vmbus_connection.rescind_work_queue);
331
332 if (vmbus_connection.work_queue)
333 destroy_workqueue(vmbus_connection.work_queue);
334
335 if (vmbus_connection.int_page) {
336 hv_free_hyperv_page(vmbus_connection.int_page);
337 vmbus_connection.int_page = NULL;
338 }
339
340 set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[0], 1);
341 set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[1], 1);
342
343 hv_free_hyperv_page(vmbus_connection.monitor_pages[0]);
344 hv_free_hyperv_page(vmbus_connection.monitor_pages[1]);
345 vmbus_connection.monitor_pages[0] = NULL;
346 vmbus_connection.monitor_pages[1] = NULL;
347}
348
349/*
350 * relid2channel - Get the channel object given its
351 * child relative id (ie channel id)
352 */
353struct vmbus_channel *relid2channel(u32 relid)
354{
355 if (vmbus_connection.channels == NULL) {
356 pr_warn_once("relid2channel: relid=%d: No channels mapped!\n", relid);
357 return NULL;
358 }
359 if (WARN_ON(relid >= MAX_CHANNEL_RELIDS))
360 return NULL;
361 return READ_ONCE(vmbus_connection.channels[relid]);
362}
363
364/*
365 * vmbus_on_event - Process a channel event notification
366 *
367 * For batched channels (default) optimize host to guest signaling
368 * by ensuring:
369 * 1. While reading the channel, we disable interrupts from host.
370 * 2. Ensure that we process all posted messages from the host
371 * before returning from this callback.
372 * 3. Once we return, enable signaling from the host. Once this
373 * state is set we check to see if additional packets are
374 * available to read. In this case we repeat the process.
375 * If this tasklet has been running for a long time
376 * then reschedule ourselves.
377 */
378void vmbus_on_event(unsigned long data)
379{
380 struct vmbus_channel *channel = (void *) data;
381 void (*callback_fn)(void *context);
382
383 trace_vmbus_on_event(channel);
384
385 hv_debug_delay_test(channel, INTERRUPT_DELAY);
386
387 /* A channel once created is persistent even when
388 * there is no driver handling the device. An
389 * unloading driver sets the onchannel_callback to NULL.
390 */
391 callback_fn = READ_ONCE(channel->onchannel_callback);
392 if (unlikely(!callback_fn))
393 return;
394
395 (*callback_fn)(channel->channel_callback_context);
396
397 if (channel->callback_mode != HV_CALL_BATCHED)
398 return;
399
400 if (likely(hv_end_read(&channel->inbound) == 0))
401 return;
402
403 hv_begin_read(&channel->inbound);
404 tasklet_schedule(&channel->callback_event);
405}
406
407/*
408 * vmbus_post_msg - Send a msg on the vmbus's message connection
409 */
410int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
411{
412 struct vmbus_channel_message_header *hdr;
413 union hv_connection_id conn_id;
414 int ret = 0;
415 int retries = 0;
416 u32 usec = 1;
417
418 conn_id.asu32 = 0;
419 conn_id.u.id = vmbus_connection.msg_conn_id;
420
421 /*
422 * hv_post_message() can have transient failures because of
423 * insufficient resources. Retry the operation a couple of
424 * times before giving up.
425 */
426 while (retries < 100) {
427 ret = hv_post_message(conn_id, 1, buffer, buflen);
428
429 switch (ret) {
430 case HV_STATUS_INVALID_CONNECTION_ID:
431 /*
432 * See vmbus_negotiate_version(): VMBus protocol 5.0
433 * and higher require that we must use
434 * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate
435 * Contact message, but on old hosts that only
436 * support VMBus protocol 4.0 or lower, here we get
437 * HV_STATUS_INVALID_CONNECTION_ID and we should
438 * return an error immediately without retrying.
439 */
440 hdr = buffer;
441 if (hdr->msgtype == CHANNELMSG_INITIATE_CONTACT)
442 return -EINVAL;
443 /*
444 * We could get this if we send messages too
445 * frequently.
446 */
447 ret = -EAGAIN;
448 break;
449 case HV_STATUS_INSUFFICIENT_MEMORY:
450 case HV_STATUS_INSUFFICIENT_BUFFERS:
451 ret = -ENOBUFS;
452 break;
453 case HV_STATUS_SUCCESS:
454 return ret;
455 default:
456 pr_err("hv_post_msg() failed; error code:%d\n", ret);
457 return -EINVAL;
458 }
459
460 retries++;
461 if (can_sleep && usec > 1000)
462 msleep(usec / 1000);
463 else if (usec < MAX_UDELAY_MS * 1000)
464 udelay(usec);
465 else
466 mdelay(usec / 1000);
467
468 if (retries < 22)
469 usec *= 2;
470 }
471 return ret;
472}
473
474/*
475 * vmbus_set_event - Send an event notification to the parent
476 */
477void vmbus_set_event(struct vmbus_channel *channel)
478{
479 u32 child_relid = channel->offermsg.child_relid;
480
481 if (!channel->is_dedicated_interrupt)
482 vmbus_send_interrupt(child_relid);
483
484 ++channel->sig_events;
485
486 if (ms_hyperv.paravisor_present) {
487 if (hv_isolation_type_snp())
488 hv_ghcb_hypercall(HVCALL_SIGNAL_EVENT, &channel->sig_event,
489 NULL, sizeof(channel->sig_event));
490 else if (hv_isolation_type_tdx())
491 hv_tdx_hypercall(HVCALL_SIGNAL_EVENT | HV_HYPERCALL_FAST_BIT,
492 channel->sig_event, 0);
493 else
494 WARN_ON_ONCE(1);
495 } else {
496 hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
497 }
498}
499EXPORT_SYMBOL_GPL(vmbus_set_event);
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 "hyperv_vmbus.h"
36
37
38struct vmbus_connection vmbus_connection = {
39 .conn_state = DISCONNECTED,
40 .next_gpadl_handle = ATOMIC_INIT(0xE1E10),
41};
42
43/*
44 * Negotiated protocol version with the host.
45 */
46__u32 vmbus_proto_version;
47EXPORT_SYMBOL_GPL(vmbus_proto_version);
48
49static __u32 vmbus_get_next_version(__u32 current_version)
50{
51 switch (current_version) {
52 case (VERSION_WIN7):
53 return VERSION_WS2008;
54
55 case (VERSION_WIN8):
56 return VERSION_WIN7;
57
58 case (VERSION_WIN8_1):
59 return VERSION_WIN8;
60
61 case (VERSION_WIN10):
62 return VERSION_WIN8_1;
63
64 case (VERSION_WS2008):
65 default:
66 return VERSION_INVAL;
67 }
68}
69
70static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
71 __u32 version)
72{
73 int ret = 0;
74 struct vmbus_channel_initiate_contact *msg;
75 unsigned long flags;
76
77 init_completion(&msginfo->waitevent);
78
79 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
80
81 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
82 msg->vmbus_version_requested = version;
83 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
84 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
85 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
86 /*
87 * We want all channel messages to be delivered on CPU 0.
88 * This has been the behavior pre-win8. This is not
89 * perf issue and having all channel messages delivered on CPU 0
90 * would be ok.
91 * For post win8 hosts, we support receiving channel messagges on
92 * all the CPUs. This is needed for kexec to work correctly where
93 * the CPU attempting to connect may not be CPU 0.
94 */
95 if (version >= VERSION_WIN8_1) {
96 msg->target_vcpu = hv_context.vp_index[get_cpu()];
97 put_cpu();
98 } else {
99 msg->target_vcpu = 0;
100 }
101
102 /*
103 * Add to list before we send the request since we may
104 * receive the response before returning from this routine
105 */
106 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
107 list_add_tail(&msginfo->msglistentry,
108 &vmbus_connection.chn_msg_list);
109
110 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
111
112 ret = vmbus_post_msg(msg,
113 sizeof(struct vmbus_channel_initiate_contact));
114 if (ret != 0) {
115 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
116 list_del(&msginfo->msglistentry);
117 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
118 flags);
119 return ret;
120 }
121
122 /* Wait for the connection response */
123 wait_for_completion(&msginfo->waitevent);
124
125 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
126 list_del(&msginfo->msglistentry);
127 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
128
129 /* Check if successful */
130 if (msginfo->response.version_response.version_supported) {
131 vmbus_connection.conn_state = CONNECTED;
132 } else {
133 return -ECONNREFUSED;
134 }
135
136 return ret;
137}
138
139/*
140 * vmbus_connect - Sends a connect request on the partition service connection
141 */
142int vmbus_connect(void)
143{
144 int ret = 0;
145 struct vmbus_channel_msginfo *msginfo = NULL;
146 __u32 version;
147
148 /* Initialize the vmbus connection */
149 vmbus_connection.conn_state = CONNECTING;
150 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con");
151 if (!vmbus_connection.work_queue) {
152 ret = -ENOMEM;
153 goto cleanup;
154 }
155
156 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
157 spin_lock_init(&vmbus_connection.channelmsg_lock);
158
159 INIT_LIST_HEAD(&vmbus_connection.chn_list);
160 mutex_init(&vmbus_connection.channel_mutex);
161
162 /*
163 * Setup the vmbus event connection for channel interrupt
164 * abstraction stuff
165 */
166 vmbus_connection.int_page =
167 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
168 if (vmbus_connection.int_page == NULL) {
169 ret = -ENOMEM;
170 goto cleanup;
171 }
172
173 vmbus_connection.recv_int_page = vmbus_connection.int_page;
174 vmbus_connection.send_int_page =
175 (void *)((unsigned long)vmbus_connection.int_page +
176 (PAGE_SIZE >> 1));
177
178 /*
179 * Setup the monitor notification facility. The 1st page for
180 * parent->child and the 2nd page for child->parent
181 */
182 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
183 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
184 if ((vmbus_connection.monitor_pages[0] == NULL) ||
185 (vmbus_connection.monitor_pages[1] == NULL)) {
186 ret = -ENOMEM;
187 goto cleanup;
188 }
189
190 msginfo = kzalloc(sizeof(*msginfo) +
191 sizeof(struct vmbus_channel_initiate_contact),
192 GFP_KERNEL);
193 if (msginfo == NULL) {
194 ret = -ENOMEM;
195 goto cleanup;
196 }
197
198 /*
199 * Negotiate a compatible VMBUS version number with the
200 * host. We start with the highest number we can support
201 * and work our way down until we negotiate a compatible
202 * version.
203 */
204
205 version = VERSION_CURRENT;
206
207 do {
208 ret = vmbus_negotiate_version(msginfo, version);
209 if (ret == -ETIMEDOUT)
210 goto cleanup;
211
212 if (vmbus_connection.conn_state == CONNECTED)
213 break;
214
215 version = vmbus_get_next_version(version);
216 } while (version != VERSION_INVAL);
217
218 if (version == VERSION_INVAL)
219 goto cleanup;
220
221 vmbus_proto_version = version;
222 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d; Vmbus version:%d.%d\n",
223 host_info_eax, host_info_ebx >> 16,
224 host_info_ebx & 0xFFFF, host_info_ecx,
225 host_info_edx >> 24, host_info_edx & 0xFFFFFF,
226 version >> 16, version & 0xFFFF);
227
228 kfree(msginfo);
229 return 0;
230
231cleanup:
232 pr_err("Unable to connect to host\n");
233
234 vmbus_connection.conn_state = DISCONNECTED;
235 vmbus_disconnect();
236
237 kfree(msginfo);
238
239 return ret;
240}
241
242void vmbus_disconnect(void)
243{
244 /*
245 * First send the unload request to the host.
246 */
247 vmbus_initiate_unload(false);
248
249 if (vmbus_connection.work_queue) {
250 drain_workqueue(vmbus_connection.work_queue);
251 destroy_workqueue(vmbus_connection.work_queue);
252 }
253
254 if (vmbus_connection.int_page) {
255 free_pages((unsigned long)vmbus_connection.int_page, 0);
256 vmbus_connection.int_page = NULL;
257 }
258
259 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
260 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
261 vmbus_connection.monitor_pages[0] = NULL;
262 vmbus_connection.monitor_pages[1] = NULL;
263}
264
265/*
266 * Map the given relid to the corresponding channel based on the
267 * per-cpu list of channels that have been affinitized to this CPU.
268 * This will be used in the channel callback path as we can do this
269 * mapping in a lock-free fashion.
270 */
271static struct vmbus_channel *pcpu_relid2channel(u32 relid)
272{
273 struct vmbus_channel *channel;
274 struct vmbus_channel *found_channel = NULL;
275 int cpu = smp_processor_id();
276 struct list_head *pcpu_head = &hv_context.percpu_list[cpu];
277
278 list_for_each_entry(channel, pcpu_head, percpu_list) {
279 if (channel->offermsg.child_relid == relid) {
280 found_channel = channel;
281 break;
282 }
283 }
284
285 return found_channel;
286}
287
288/*
289 * relid2channel - Get the channel object given its
290 * child relative id (ie channel id)
291 */
292struct 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 * process_chn_event - Process a channel event notification
325 */
326static void process_chn_event(u32 relid)
327{
328 struct vmbus_channel *channel;
329 void *arg;
330 bool read_state;
331 u32 bytes_to_read;
332
333 /*
334 * Find the channel based on this relid and invokes the
335 * channel callback to process the event
336 */
337 channel = pcpu_relid2channel(relid);
338
339 if (!channel)
340 return;
341
342 /*
343 * A channel once created is persistent even when there
344 * is no driver handling the device. An unloading driver
345 * sets the onchannel_callback to NULL on the same CPU
346 * as where this interrupt is handled (in an interrupt context).
347 * Thus, checking and invoking the driver specific callback takes
348 * care of orderly unloading of the driver.
349 */
350
351 if (channel->onchannel_callback != NULL) {
352 arg = channel->channel_callback_context;
353 read_state = channel->batched_reading;
354 /*
355 * This callback reads the messages sent by the host.
356 * We can optimize host to guest signaling by ensuring:
357 * 1. While reading the channel, we disable interrupts from
358 * host.
359 * 2. Ensure that we process all posted messages from the host
360 * before returning from this callback.
361 * 3. Once we return, enable signaling from the host. Once this
362 * state is set we check to see if additional packets are
363 * available to read. In this case we repeat the process.
364 */
365
366 do {
367 if (read_state)
368 hv_begin_read(&channel->inbound);
369 channel->onchannel_callback(arg);
370 if (read_state)
371 bytes_to_read = hv_end_read(&channel->inbound);
372 else
373 bytes_to_read = 0;
374 } while (read_state && (bytes_to_read != 0));
375 }
376}
377
378/*
379 * vmbus_on_event - Handler for events
380 */
381void vmbus_on_event(unsigned long data)
382{
383 u32 dword;
384 u32 maxdword;
385 int bit;
386 u32 relid;
387 u32 *recv_int_page = NULL;
388 void *page_addr;
389 int cpu = smp_processor_id();
390 union hv_synic_event_flags *event;
391
392 if (vmbus_proto_version < VERSION_WIN8) {
393 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5;
394 recv_int_page = vmbus_connection.recv_int_page;
395 } else {
396 /*
397 * When the host is win8 and beyond, the event page
398 * can be directly checked to get the id of the channel
399 * that has the interrupt pending.
400 */
401 maxdword = HV_EVENT_FLAGS_DWORD_COUNT;
402 page_addr = hv_context.synic_event_page[cpu];
403 event = (union hv_synic_event_flags *)page_addr +
404 VMBUS_MESSAGE_SINT;
405 recv_int_page = event->flags32;
406 }
407
408
409
410 /* Check events */
411 if (!recv_int_page)
412 return;
413 for (dword = 0; dword < maxdword; dword++) {
414 if (!recv_int_page[dword])
415 continue;
416 for (bit = 0; bit < 32; bit++) {
417 if (sync_test_and_clear_bit(bit,
418 (unsigned long *)&recv_int_page[dword])) {
419 relid = (dword << 5) + bit;
420
421 if (relid == 0)
422 /*
423 * Special case - vmbus
424 * channel protocol msg
425 */
426 continue;
427
428 process_chn_event(relid);
429 }
430 }
431 }
432}
433
434/*
435 * vmbus_post_msg - Send a msg on the vmbus's message connection
436 */
437int vmbus_post_msg(void *buffer, size_t buflen)
438{
439 union hv_connection_id conn_id;
440 int ret = 0;
441 int retries = 0;
442 u32 msec = 1;
443
444 conn_id.asu32 = 0;
445 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
446
447 /*
448 * hv_post_message() can have transient failures because of
449 * insufficient resources. Retry the operation a couple of
450 * times before giving up.
451 */
452 while (retries < 20) {
453 ret = hv_post_message(conn_id, 1, buffer, buflen);
454
455 switch (ret) {
456 case HV_STATUS_INVALID_CONNECTION_ID:
457 /*
458 * We could get this if we send messages too
459 * frequently.
460 */
461 ret = -EAGAIN;
462 break;
463 case HV_STATUS_INSUFFICIENT_MEMORY:
464 case HV_STATUS_INSUFFICIENT_BUFFERS:
465 ret = -ENOMEM;
466 break;
467 case HV_STATUS_SUCCESS:
468 return ret;
469 default:
470 pr_err("hv_post_msg() failed; error code:%d\n", ret);
471 return -EINVAL;
472 }
473
474 retries++;
475 msleep(msec);
476 if (msec < 2048)
477 msec *= 2;
478 }
479 return ret;
480}
481
482/*
483 * vmbus_set_event - Send an event notification to the parent
484 */
485void vmbus_set_event(struct vmbus_channel *channel)
486{
487 u32 child_relid = channel->offermsg.child_relid;
488
489 if (!channel->is_dedicated_interrupt) {
490 /* Each u32 represents 32 channels */
491 sync_set_bit(child_relid & 31,
492 (unsigned long *)vmbus_connection.send_int_page +
493 (child_relid >> 5));
494 }
495
496 hv_do_hypercall(HVCALL_SIGNAL_EVENT, channel->sig_event, NULL);
497}