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 39 struct vmbus_connection vmbus_connection = { 40 .conn_state = DISCONNECTED, 41 .next_gpadl_handle = ATOMIC_INIT(0xE1E10), 42 }; 43 EXPORT_SYMBOL_GPL(vmbus_connection); 44 45 /* 46 * Negotiated protocol version with the host. 47 */ 48 __u32 vmbus_proto_version; 49 EXPORT_SYMBOL_GPL(vmbus_proto_version); 50 51 static __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_WIN10_V5): 67 return VERSION_WIN10; 68 69 case (VERSION_WS2008): 70 default: 71 return VERSION_INVAL; 72 } 73 } 74 75 static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, 76 __u32 version) 77 { 78 int ret = 0; 79 struct vmbus_channel_initiate_contact *msg; 80 unsigned long flags; 81 82 init_completion(&msginfo->waitevent); 83 84 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg; 85 86 memset(msg, 0, sizeof(*msg)); 87 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT; 88 msg->vmbus_version_requested = version; 89 90 /* 91 * VMBus protocol 5.0 (VERSION_WIN10_V5) requires that we must use 92 * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate Contact Message, 93 * and for subsequent messages, we must use the Message Connection ID 94 * field in the host-returned Version Response Message. And, with 95 * VERSION_WIN10_V5, we don't use msg->interrupt_page, but we tell 96 * the host explicitly that we still use VMBUS_MESSAGE_SINT(2) for 97 * compatibility. 98 * 99 * On old hosts, we should always use VMBUS_MESSAGE_CONNECTION_ID (1). 100 */ 101 if (version >= VERSION_WIN10_V5) { 102 msg->msg_sint = VMBUS_MESSAGE_SINT; 103 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID_4; 104 } else { 105 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page); 106 vmbus_connection.msg_conn_id = VMBUS_MESSAGE_CONNECTION_ID; 107 } 108 109 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]); 110 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]); 111 /* 112 * We want all channel messages to be delivered on CPU 0. 113 * This has been the behavior pre-win8. This is not 114 * perf issue and having all channel messages delivered on CPU 0 115 * would be ok. 116 * For post win8 hosts, we support receiving channel messagges on 117 * all the CPUs. This is needed for kexec to work correctly where 118 * the CPU attempting to connect may not be CPU 0. 119 */ 120 if (version >= VERSION_WIN8_1) { 121 msg->target_vcpu = 122 hv_cpu_number_to_vp_number(smp_processor_id()); 123 vmbus_connection.connect_cpu = smp_processor_id(); 124 } else { 125 msg->target_vcpu = 0; 126 vmbus_connection.connect_cpu = 0; 127 } 128 129 /* 130 * Add to list before we send the request since we may 131 * receive the response before returning from this routine 132 */ 133 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 134 list_add_tail(&msginfo->msglistentry, 135 &vmbus_connection.chn_msg_list); 136 137 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 138 139 ret = vmbus_post_msg(msg, 140 sizeof(struct vmbus_channel_initiate_contact), 141 true); 142 143 trace_vmbus_negotiate_version(msg, ret); 144 145 if (ret != 0) { 146 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 147 list_del(&msginfo->msglistentry); 148 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, 149 flags); 150 return ret; 151 } 152 153 /* Wait for the connection response */ 154 wait_for_completion(&msginfo->waitevent); 155 156 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 157 list_del(&msginfo->msglistentry); 158 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 159 160 /* Check if successful */ 161 if (msginfo->response.version_response.version_supported) { 162 vmbus_connection.conn_state = CONNECTED; 163 164 if (version >= VERSION_WIN10_V5) 165 vmbus_connection.msg_conn_id = 166 msginfo->response.version_response.msg_conn_id; 167 } else { 168 return -ECONNREFUSED; 169 } 170 171 return ret; 172 } 173 174 /* 175 * vmbus_connect - Sends a connect request on the partition service connection 176 */ 177 int vmbus_connect(void) 178 { 179 int ret = 0; 180 struct vmbus_channel_msginfo *msginfo = NULL; 181 __u32 version; 182 183 /* Initialize the vmbus connection */ 184 vmbus_connection.conn_state = CONNECTING; 185 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con"); 186 if (!vmbus_connection.work_queue) { 187 ret = -ENOMEM; 188 goto cleanup; 189 } 190 191 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list); 192 spin_lock_init(&vmbus_connection.channelmsg_lock); 193 194 INIT_LIST_HEAD(&vmbus_connection.chn_list); 195 mutex_init(&vmbus_connection.channel_mutex); 196 197 /* 198 * Setup the vmbus event connection for channel interrupt 199 * abstraction stuff 200 */ 201 vmbus_connection.int_page = 202 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0); 203 if (vmbus_connection.int_page == NULL) { 204 ret = -ENOMEM; 205 goto cleanup; 206 } 207 208 vmbus_connection.recv_int_page = vmbus_connection.int_page; 209 vmbus_connection.send_int_page = 210 (void *)((unsigned long)vmbus_connection.int_page + 211 (PAGE_SIZE >> 1)); 212 213 /* 214 * Setup the monitor notification facility. The 1st page for 215 * parent->child and the 2nd page for child->parent 216 */ 217 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 218 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 219 if ((vmbus_connection.monitor_pages[0] == NULL) || 220 (vmbus_connection.monitor_pages[1] == NULL)) { 221 ret = -ENOMEM; 222 goto cleanup; 223 } 224 225 msginfo = kzalloc(sizeof(*msginfo) + 226 sizeof(struct vmbus_channel_initiate_contact), 227 GFP_KERNEL); 228 if (msginfo == NULL) { 229 ret = -ENOMEM; 230 goto cleanup; 231 } 232 233 /* 234 * Negotiate a compatible VMBUS version number with the 235 * host. We start with the highest number we can support 236 * and work our way down until we negotiate a compatible 237 * version. 238 */ 239 240 version = VERSION_CURRENT; 241 242 do { 243 ret = vmbus_negotiate_version(msginfo, version); 244 if (ret == -ETIMEDOUT) 245 goto cleanup; 246 247 if (vmbus_connection.conn_state == CONNECTED) 248 break; 249 250 version = vmbus_get_next_version(version); 251 } while (version != VERSION_INVAL); 252 253 if (version == VERSION_INVAL) 254 goto cleanup; 255 256 vmbus_proto_version = version; 257 pr_info("Vmbus version:%d.%d\n", 258 version >> 16, version & 0xFFFF); 259 260 kfree(msginfo); 261 return 0; 262 263 cleanup: 264 pr_err("Unable to connect to host\n"); 265 266 vmbus_connection.conn_state = DISCONNECTED; 267 vmbus_disconnect(); 268 269 kfree(msginfo); 270 271 return ret; 272 } 273 274 void vmbus_disconnect(void) 275 { 276 /* 277 * First send the unload request to the host. 278 */ 279 vmbus_initiate_unload(false); 280 281 if (vmbus_connection.work_queue) { 282 drain_workqueue(vmbus_connection.work_queue); 283 destroy_workqueue(vmbus_connection.work_queue); 284 } 285 286 if (vmbus_connection.int_page) { 287 free_pages((unsigned long)vmbus_connection.int_page, 0); 288 vmbus_connection.int_page = NULL; 289 } 290 291 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0); 292 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0); 293 vmbus_connection.monitor_pages[0] = NULL; 294 vmbus_connection.monitor_pages[1] = NULL; 295 } 296 297 /* 298 * relid2channel - Get the channel object given its 299 * child relative id (ie channel id) 300 */ 301 struct vmbus_channel *relid2channel(u32 relid) 302 { 303 struct vmbus_channel *channel; 304 struct vmbus_channel *found_channel = NULL; 305 struct list_head *cur, *tmp; 306 struct vmbus_channel *cur_sc; 307 308 BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex)); 309 310 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { 311 if (channel->offermsg.child_relid == relid) { 312 found_channel = channel; 313 break; 314 } else if (!list_empty(&channel->sc_list)) { 315 /* 316 * Deal with sub-channels. 317 */ 318 list_for_each_safe(cur, tmp, &channel->sc_list) { 319 cur_sc = list_entry(cur, struct vmbus_channel, 320 sc_list); 321 if (cur_sc->offermsg.child_relid == relid) { 322 found_channel = cur_sc; 323 break; 324 } 325 } 326 } 327 } 328 329 return found_channel; 330 } 331 332 /* 333 * vmbus_on_event - Process a channel event notification 334 * 335 * For batched channels (default) optimize host to guest signaling 336 * by ensuring: 337 * 1. While reading the channel, we disable interrupts from host. 338 * 2. Ensure that we process all posted messages from the host 339 * before returning from this callback. 340 * 3. Once we return, enable signaling from the host. Once this 341 * state is set we check to see if additional packets are 342 * available to read. In this case we repeat the process. 343 * If this tasklet has been running for a long time 344 * then reschedule ourselves. 345 */ 346 void vmbus_on_event(unsigned long data) 347 { 348 struct vmbus_channel *channel = (void *) data; 349 unsigned long time_limit = jiffies + 2; 350 351 trace_vmbus_on_event(channel); 352 353 do { 354 void (*callback_fn)(void *); 355 356 /* A channel once created is persistent even when 357 * there is no driver handling the device. An 358 * unloading driver sets the onchannel_callback to NULL. 359 */ 360 callback_fn = READ_ONCE(channel->onchannel_callback); 361 if (unlikely(callback_fn == NULL)) 362 return; 363 364 (*callback_fn)(channel->channel_callback_context); 365 366 if (channel->callback_mode != HV_CALL_BATCHED) 367 return; 368 369 if (likely(hv_end_read(&channel->inbound) == 0)) 370 return; 371 372 hv_begin_read(&channel->inbound); 373 } while (likely(time_before(jiffies, time_limit))); 374 375 /* The time limit (2 jiffies) has been reached */ 376 tasklet_schedule(&channel->callback_event); 377 } 378 379 /* 380 * vmbus_post_msg - Send a msg on the vmbus's message connection 381 */ 382 int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep) 383 { 384 struct vmbus_channel_message_header *hdr; 385 union hv_connection_id conn_id; 386 int ret = 0; 387 int retries = 0; 388 u32 usec = 1; 389 390 conn_id.asu32 = 0; 391 conn_id.u.id = vmbus_connection.msg_conn_id; 392 393 /* 394 * hv_post_message() can have transient failures because of 395 * insufficient resources. Retry the operation a couple of 396 * times before giving up. 397 */ 398 while (retries < 100) { 399 ret = hv_post_message(conn_id, 1, buffer, buflen); 400 401 switch (ret) { 402 case HV_STATUS_INVALID_CONNECTION_ID: 403 /* 404 * See vmbus_negotiate_version(): VMBus protocol 5.0 405 * requires that we must use 406 * VMBUS_MESSAGE_CONNECTION_ID_4 for the Initiate 407 * Contact message, but on old hosts that only 408 * support VMBus protocol 4.0 or lower, here we get 409 * HV_STATUS_INVALID_CONNECTION_ID and we should 410 * return an error immediately without retrying. 411 */ 412 hdr = buffer; 413 if (hdr->msgtype == CHANNELMSG_INITIATE_CONTACT) 414 return -EINVAL; 415 /* 416 * We could get this if we send messages too 417 * frequently. 418 */ 419 ret = -EAGAIN; 420 break; 421 case HV_STATUS_INSUFFICIENT_MEMORY: 422 case HV_STATUS_INSUFFICIENT_BUFFERS: 423 ret = -ENOBUFS; 424 break; 425 case HV_STATUS_SUCCESS: 426 return ret; 427 default: 428 pr_err("hv_post_msg() failed; error code:%d\n", ret); 429 return -EINVAL; 430 } 431 432 retries++; 433 if (can_sleep && usec > 1000) 434 msleep(usec / 1000); 435 else if (usec < MAX_UDELAY_MS * 1000) 436 udelay(usec); 437 else 438 mdelay(usec / 1000); 439 440 if (retries < 22) 441 usec *= 2; 442 } 443 return ret; 444 } 445 446 /* 447 * vmbus_set_event - Send an event notification to the parent 448 */ 449 void vmbus_set_event(struct vmbus_channel *channel) 450 { 451 u32 child_relid = channel->offermsg.child_relid; 452 453 if (!channel->is_dedicated_interrupt) 454 vmbus_send_interrupt(child_relid); 455 456 ++channel->sig_events; 457 458 hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event); 459 } 460 EXPORT_SYMBOL_GPL(vmbus_set_event); 461