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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/mshyperv.h>
35
36#include "hyperv_vmbus.h"
37
38
39struct vmbus_connection vmbus_connection = {
40 .conn_state = DISCONNECTED,
41 .next_gpadl_handle = ATOMIC_INIT(0xE1E10),
42};
43EXPORT_SYMBOL_GPL(vmbus_connection);
44
45/*
46 * Negotiated protocol version with the host.
47 */
48__u32 vmbus_proto_version;
49EXPORT_SYMBOL_GPL(vmbus_proto_version);
50
51static __u32 vmbus_get_next_version(__u32 current_version)
52{
53 switch (current_version) {
54 case (VERSION_WIN7):
55 return VERSION_WS2008;
56
57 case (VERSION_WIN8):
58 return VERSION_WIN7;
59
60 case (VERSION_WIN8_1):
61 return VERSION_WIN8;
62
63 case (VERSION_WIN10):
64 return VERSION_WIN8_1;
65
66 case (VERSION_WS2008):
67 default:
68 return VERSION_INVAL;
69 }
70}
71
72static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
73 __u32 version)
74{
75 int ret = 0;
76 struct vmbus_channel_initiate_contact *msg;
77 unsigned long flags;
78
79 init_completion(&msginfo->waitevent);
80
81 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg;
82
83 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT;
84 msg->vmbus_version_requested = version;
85 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page);
86 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]);
87 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]);
88 /*
89 * We want all channel messages to be delivered on CPU 0.
90 * This has been the behavior pre-win8. This is not
91 * perf issue and having all channel messages delivered on CPU 0
92 * would be ok.
93 * For post win8 hosts, we support receiving channel messagges on
94 * all the CPUs. This is needed for kexec to work correctly where
95 * the CPU attempting to connect may not be CPU 0.
96 */
97 if (version >= VERSION_WIN8_1) {
98 msg->target_vcpu =
99 hv_cpu_number_to_vp_number(smp_processor_id());
100 vmbus_connection.connect_cpu = smp_processor_id();
101 } else {
102 msg->target_vcpu = 0;
103 vmbus_connection.connect_cpu = 0;
104 }
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 } 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 */
150int 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 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list);
165 spin_lock_init(&vmbus_connection.channelmsg_lock);
166
167 INIT_LIST_HEAD(&vmbus_connection.chn_list);
168 mutex_init(&vmbus_connection.channel_mutex);
169
170 /*
171 * Setup the vmbus event connection for channel interrupt
172 * abstraction stuff
173 */
174 vmbus_connection.int_page =
175 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0);
176 if (vmbus_connection.int_page == NULL) {
177 ret = -ENOMEM;
178 goto cleanup;
179 }
180
181 vmbus_connection.recv_int_page = vmbus_connection.int_page;
182 vmbus_connection.send_int_page =
183 (void *)((unsigned long)vmbus_connection.int_page +
184 (PAGE_SIZE >> 1));
185
186 /*
187 * Setup the monitor notification facility. The 1st page for
188 * parent->child and the 2nd page for child->parent
189 */
190 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
191 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0);
192 if ((vmbus_connection.monitor_pages[0] == NULL) ||
193 (vmbus_connection.monitor_pages[1] == NULL)) {
194 ret = -ENOMEM;
195 goto cleanup;
196 }
197
198 msginfo = kzalloc(sizeof(*msginfo) +
199 sizeof(struct vmbus_channel_initiate_contact),
200 GFP_KERNEL);
201 if (msginfo == NULL) {
202 ret = -ENOMEM;
203 goto cleanup;
204 }
205
206 /*
207 * Negotiate a compatible VMBUS version number with the
208 * host. We start with the highest number we can support
209 * and work our way down until we negotiate a compatible
210 * version.
211 */
212
213 version = VERSION_CURRENT;
214
215 do {
216 ret = vmbus_negotiate_version(msginfo, version);
217 if (ret == -ETIMEDOUT)
218 goto cleanup;
219
220 if (vmbus_connection.conn_state == CONNECTED)
221 break;
222
223 version = vmbus_get_next_version(version);
224 } while (version != VERSION_INVAL);
225
226 if (version == VERSION_INVAL)
227 goto cleanup;
228
229 vmbus_proto_version = version;
230 pr_info("Vmbus version:%d.%d\n",
231 version >> 16, version & 0xFFFF);
232
233 kfree(msginfo);
234 return 0;
235
236cleanup:
237 pr_err("Unable to connect to host\n");
238
239 vmbus_connection.conn_state = DISCONNECTED;
240 vmbus_disconnect();
241
242 kfree(msginfo);
243
244 return ret;
245}
246
247void vmbus_disconnect(void)
248{
249 /*
250 * First send the unload request to the host.
251 */
252 vmbus_initiate_unload(false);
253
254 if (vmbus_connection.work_queue) {
255 drain_workqueue(vmbus_connection.work_queue);
256 destroy_workqueue(vmbus_connection.work_queue);
257 }
258
259 if (vmbus_connection.int_page) {
260 free_pages((unsigned long)vmbus_connection.int_page, 0);
261 vmbus_connection.int_page = NULL;
262 }
263
264 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0);
265 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0);
266 vmbus_connection.monitor_pages[0] = NULL;
267 vmbus_connection.monitor_pages[1] = NULL;
268}
269
270/*
271 * relid2channel - Get the channel object given its
272 * child relative id (ie channel id)
273 */
274struct vmbus_channel *relid2channel(u32 relid)
275{
276 struct vmbus_channel *channel;
277 struct vmbus_channel *found_channel = NULL;
278 struct list_head *cur, *tmp;
279 struct vmbus_channel *cur_sc;
280
281 BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex));
282
283 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
284 if (channel->offermsg.child_relid == relid) {
285 found_channel = channel;
286 break;
287 } else if (!list_empty(&channel->sc_list)) {
288 /*
289 * Deal with sub-channels.
290 */
291 list_for_each_safe(cur, tmp, &channel->sc_list) {
292 cur_sc = list_entry(cur, struct vmbus_channel,
293 sc_list);
294 if (cur_sc->offermsg.child_relid == relid) {
295 found_channel = cur_sc;
296 break;
297 }
298 }
299 }
300 }
301
302 return found_channel;
303}
304
305/*
306 * vmbus_on_event - Process a channel event notification
307 *
308 * For batched channels (default) optimize host to guest signaling
309 * by ensuring:
310 * 1. While reading the channel, we disable interrupts from host.
311 * 2. Ensure that we process all posted messages from the host
312 * before returning from this callback.
313 * 3. Once we return, enable signaling from the host. Once this
314 * state is set we check to see if additional packets are
315 * available to read. In this case we repeat the process.
316 * If this tasklet has been running for a long time
317 * then reschedule ourselves.
318 */
319void vmbus_on_event(unsigned long data)
320{
321 struct vmbus_channel *channel = (void *) data;
322 unsigned long time_limit = jiffies + 2;
323
324 trace_vmbus_on_event(channel);
325
326 do {
327 void (*callback_fn)(void *);
328
329 /* A channel once created is persistent even when
330 * there is no driver handling the device. An
331 * unloading driver sets the onchannel_callback to NULL.
332 */
333 callback_fn = READ_ONCE(channel->onchannel_callback);
334 if (unlikely(callback_fn == NULL))
335 return;
336
337 (*callback_fn)(channel->channel_callback_context);
338
339 if (channel->callback_mode != HV_CALL_BATCHED)
340 return;
341
342 if (likely(hv_end_read(&channel->inbound) == 0))
343 return;
344
345 hv_begin_read(&channel->inbound);
346 } while (likely(time_before(jiffies, time_limit)));
347
348 /* The time limit (2 jiffies) has been reached */
349 tasklet_schedule(&channel->callback_event);
350}
351
352/*
353 * vmbus_post_msg - Send a msg on the vmbus's message connection
354 */
355int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
356{
357 union hv_connection_id conn_id;
358 int ret = 0;
359 int retries = 0;
360 u32 usec = 1;
361
362 conn_id.asu32 = 0;
363 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID;
364
365 /*
366 * hv_post_message() can have transient failures because of
367 * insufficient resources. Retry the operation a couple of
368 * times before giving up.
369 */
370 while (retries < 100) {
371 ret = hv_post_message(conn_id, 1, buffer, buflen);
372
373 switch (ret) {
374 case HV_STATUS_INVALID_CONNECTION_ID:
375 /*
376 * We could get this if we send messages too
377 * frequently.
378 */
379 ret = -EAGAIN;
380 break;
381 case HV_STATUS_INSUFFICIENT_MEMORY:
382 case HV_STATUS_INSUFFICIENT_BUFFERS:
383 ret = -ENOBUFS;
384 break;
385 case HV_STATUS_SUCCESS:
386 return ret;
387 default:
388 pr_err("hv_post_msg() failed; error code:%d\n", ret);
389 return -EINVAL;
390 }
391
392 retries++;
393 if (can_sleep && usec > 1000)
394 msleep(usec / 1000);
395 else if (usec < MAX_UDELAY_MS * 1000)
396 udelay(usec);
397 else
398 mdelay(usec / 1000);
399
400 if (retries < 22)
401 usec *= 2;
402 }
403 return ret;
404}
405
406/*
407 * vmbus_set_event - Send an event notification to the parent
408 */
409void vmbus_set_event(struct vmbus_channel *channel)
410{
411 u32 child_relid = channel->offermsg.child_relid;
412
413 if (!channel->is_dedicated_interrupt)
414 vmbus_send_interrupt(child_relid);
415
416 ++channel->sig_events;
417
418 hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
419}
420EXPORT_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 <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 .all_offers_delivered_event = COMPLETION_INITIALIZER(
38 vmbus_connection.all_offers_delivered_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 /*
242 * If set_memory_decrypted() fails, the encryption state
243 * of the memory is unknown. So leak the memory instead
244 * of risking returning decrypted memory to the free list.
245 * For simplicity, always handle both pages the same.
246 */
247 vmbus_connection.monitor_pages[0] = NULL;
248 vmbus_connection.monitor_pages[1] = NULL;
249 goto cleanup;
250 }
251
252 /*
253 * Set_memory_decrypted() will change the memory contents if
254 * decryption occurs, so zero monitor pages here.
255 */
256 memset(vmbus_connection.monitor_pages[0], 0x00, HV_HYP_PAGE_SIZE);
257 memset(vmbus_connection.monitor_pages[1], 0x00, HV_HYP_PAGE_SIZE);
258
259 msginfo = kzalloc(sizeof(*msginfo) +
260 sizeof(struct vmbus_channel_initiate_contact),
261 GFP_KERNEL);
262 if (msginfo == NULL) {
263 ret = -ENOMEM;
264 goto cleanup;
265 }
266
267 /*
268 * Negotiate a compatible VMBUS version number with the
269 * host. We start with the highest number we can support
270 * and work our way down until we negotiate a compatible
271 * version.
272 */
273
274 for (i = 0; ; i++) {
275 if (i == ARRAY_SIZE(vmbus_versions)) {
276 ret = -EDOM;
277 goto cleanup;
278 }
279
280 version = vmbus_versions[i];
281 if (version > max_version)
282 continue;
283
284 ret = vmbus_negotiate_version(msginfo, version);
285 if (ret == -ETIMEDOUT)
286 goto cleanup;
287
288 if (vmbus_connection.conn_state == CONNECTED)
289 break;
290 }
291
292 if (hv_is_isolation_supported() && version < VERSION_WIN10_V5_2) {
293 pr_err("Invalid VMBus version %d.%d (expected >= %d.%d) from the host supporting isolation\n",
294 version >> 16, version & 0xFFFF, VERSION_WIN10_V5_2 >> 16, VERSION_WIN10_V5_2 & 0xFFFF);
295 ret = -EINVAL;
296 goto cleanup;
297 }
298
299 vmbus_proto_version = version;
300 pr_info("Vmbus version:%d.%d\n",
301 version >> 16, version & 0xFFFF);
302
303 vmbus_connection.channels = kcalloc(MAX_CHANNEL_RELIDS,
304 sizeof(struct vmbus_channel *),
305 GFP_KERNEL);
306 if (vmbus_connection.channels == NULL) {
307 ret = -ENOMEM;
308 goto cleanup;
309 }
310
311 kfree(msginfo);
312 return 0;
313
314cleanup:
315 pr_err("Unable to connect to host\n");
316
317 vmbus_connection.conn_state = DISCONNECTED;
318 vmbus_disconnect();
319
320 kfree(msginfo);
321
322 return ret;
323}
324
325void vmbus_disconnect(void)
326{
327 /*
328 * First send the unload request to the host.
329 */
330 vmbus_initiate_unload(false);
331
332 if (vmbus_connection.handle_sub_chan_wq)
333 destroy_workqueue(vmbus_connection.handle_sub_chan_wq);
334
335 if (vmbus_connection.handle_primary_chan_wq)
336 destroy_workqueue(vmbus_connection.handle_primary_chan_wq);
337
338 if (vmbus_connection.rescind_work_queue)
339 destroy_workqueue(vmbus_connection.rescind_work_queue);
340
341 if (vmbus_connection.work_queue)
342 destroy_workqueue(vmbus_connection.work_queue);
343
344 if (vmbus_connection.int_page) {
345 hv_free_hyperv_page(vmbus_connection.int_page);
346 vmbus_connection.int_page = NULL;
347 }
348
349 if (vmbus_connection.monitor_pages[0]) {
350 if (!set_memory_encrypted(
351 (unsigned long)vmbus_connection.monitor_pages[0], 1))
352 hv_free_hyperv_page(vmbus_connection.monitor_pages[0]);
353 vmbus_connection.monitor_pages[0] = NULL;
354 }
355
356 if (vmbus_connection.monitor_pages[1]) {
357 if (!set_memory_encrypted(
358 (unsigned long)vmbus_connection.monitor_pages[1], 1))
359 hv_free_hyperv_page(vmbus_connection.monitor_pages[1]);
360 vmbus_connection.monitor_pages[1] = NULL;
361 }
362}
363
364/*
365 * relid2channel - Get the channel object given its
366 * child relative id (ie channel id)
367 */
368struct vmbus_channel *relid2channel(u32 relid)
369{
370 if (vmbus_connection.channels == NULL) {
371 pr_warn_once("relid2channel: relid=%d: No channels mapped!\n", relid);
372 return NULL;
373 }
374 if (WARN_ON(relid >= MAX_CHANNEL_RELIDS))
375 return NULL;
376 return READ_ONCE(vmbus_connection.channels[relid]);
377}
378
379/*
380 * vmbus_on_event - Process a channel event notification
381 *
382 * For batched channels (default) optimize host to guest signaling
383 * by ensuring:
384 * 1. While reading the channel, we disable interrupts from host.
385 * 2. Ensure that we process all posted messages from the host
386 * before returning from this callback.
387 * 3. Once we return, enable signaling from the host. Once this
388 * state is set we check to see if additional packets are
389 * available to read. In this case we repeat the process.
390 * If this tasklet has been running for a long time
391 * then reschedule ourselves.
392 */
393void vmbus_on_event(unsigned long data)
394{
395 struct vmbus_channel *channel = (void *) data;
396 void (*callback_fn)(void *context);
397
398 trace_vmbus_on_event(channel);
399
400 hv_debug_delay_test(channel, INTERRUPT_DELAY);
401
402 /* A channel once created is persistent even when
403 * there is no driver handling the device. An
404 * unloading driver sets the onchannel_callback to NULL.
405 */
406 callback_fn = READ_ONCE(channel->onchannel_callback);
407 if (unlikely(!callback_fn))
408 return;
409
410 (*callback_fn)(channel->channel_callback_context);
411
412 if (channel->callback_mode != HV_CALL_BATCHED)
413 return;
414
415 if (likely(hv_end_read(&channel->inbound) == 0))
416 return;
417
418 hv_begin_read(&channel->inbound);
419 tasklet_schedule(&channel->callback_event);
420}
421
422/*
423 * vmbus_post_msg - Send a msg on the vmbus's message connection
424 */
425int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
426{
427 struct vmbus_channel_message_header *hdr;
428 union hv_connection_id conn_id;
429 int ret = 0;
430 int retries = 0;
431 u32 usec = 1;
432
433 conn_id.asu32 = 0;
434 conn_id.u.id = vmbus_connection.msg_conn_id;
435
436 /*
437 * hv_post_message() can have transient failures because of
438 * insufficient resources. Retry the operation a couple of
439 * times before giving up.
440 */
441 while (retries < 100) {
442 ret = hv_post_message(conn_id, 1, buffer, buflen);
443
444 switch (ret) {
445 case HV_STATUS_INVALID_CONNECTION_ID:
446 /*
447 * See vmbus_negotiate_version(): VMBus protocol 5.0
448 * and higher require that we must use
449 * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate
450 * Contact message, but on old hosts that only
451 * support VMBus protocol 4.0 or lower, here we get
452 * HV_STATUS_INVALID_CONNECTION_ID and we should
453 * return an error immediately without retrying.
454 */
455 hdr = buffer;
456 if (hdr->msgtype == CHANNELMSG_INITIATE_CONTACT)
457 return -EINVAL;
458 /*
459 * We could get this if we send messages too
460 * frequently.
461 */
462 ret = -EAGAIN;
463 break;
464 case HV_STATUS_INSUFFICIENT_MEMORY:
465 case HV_STATUS_INSUFFICIENT_BUFFERS:
466 ret = -ENOBUFS;
467 break;
468 case HV_STATUS_SUCCESS:
469 return ret;
470 default:
471 pr_err("hv_post_msg() failed; error code:%d\n", ret);
472 return -EINVAL;
473 }
474
475 retries++;
476 if (can_sleep && usec > 1000)
477 msleep(usec / 1000);
478 else if (usec < MAX_UDELAY_MS * 1000)
479 udelay(usec);
480 else
481 mdelay(usec / 1000);
482
483 if (retries < 22)
484 usec *= 2;
485 }
486 return ret;
487}
488
489/*
490 * vmbus_set_event - Send an event notification to the parent
491 */
492void vmbus_set_event(struct vmbus_channel *channel)
493{
494 u32 child_relid = channel->offermsg.child_relid;
495
496 if (!channel->is_dedicated_interrupt)
497 vmbus_send_interrupt(child_relid);
498
499 ++channel->sig_events;
500
501 if (ms_hyperv.paravisor_present) {
502 if (hv_isolation_type_snp())
503 hv_ghcb_hypercall(HVCALL_SIGNAL_EVENT, &channel->sig_event,
504 NULL, sizeof(channel->sig_event));
505 else if (hv_isolation_type_tdx())
506 hv_tdx_hypercall(HVCALL_SIGNAL_EVENT | HV_HYPERCALL_FAST_BIT,
507 channel->sig_event, 0);
508 else
509 WARN_ON_ONCE(1);
510 } else {
511 hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
512 }
513}
514EXPORT_SYMBOL_GPL(vmbus_set_event);