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 38 struct 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; 47 EXPORT_SYMBOL_GPL(vmbus_proto_version); 48 49 static __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 70 static 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 */ 92 msg->target_vcpu = 0; 93 94 /* 95 * Add to list before we send the request since we may 96 * receive the response before returning from this routine 97 */ 98 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 99 list_add_tail(&msginfo->msglistentry, 100 &vmbus_connection.chn_msg_list); 101 102 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 103 104 ret = vmbus_post_msg(msg, 105 sizeof(struct vmbus_channel_initiate_contact)); 106 if (ret != 0) { 107 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 108 list_del(&msginfo->msglistentry); 109 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, 110 flags); 111 return ret; 112 } 113 114 /* Wait for the connection response */ 115 wait_for_completion(&msginfo->waitevent); 116 117 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 118 list_del(&msginfo->msglistentry); 119 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 120 121 /* Check if successful */ 122 if (msginfo->response.version_response.version_supported) { 123 vmbus_connection.conn_state = CONNECTED; 124 } else { 125 return -ECONNREFUSED; 126 } 127 128 return ret; 129 } 130 131 /* 132 * vmbus_connect - Sends a connect request on the partition service connection 133 */ 134 int vmbus_connect(void) 135 { 136 int ret = 0; 137 struct vmbus_channel_msginfo *msginfo = NULL; 138 __u32 version; 139 140 /* Initialize the vmbus connection */ 141 vmbus_connection.conn_state = CONNECTING; 142 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con"); 143 if (!vmbus_connection.work_queue) { 144 ret = -ENOMEM; 145 goto cleanup; 146 } 147 148 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list); 149 spin_lock_init(&vmbus_connection.channelmsg_lock); 150 151 INIT_LIST_HEAD(&vmbus_connection.chn_list); 152 mutex_init(&vmbus_connection.channel_mutex); 153 154 /* 155 * Setup the vmbus event connection for channel interrupt 156 * abstraction stuff 157 */ 158 vmbus_connection.int_page = 159 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0); 160 if (vmbus_connection.int_page == NULL) { 161 ret = -ENOMEM; 162 goto cleanup; 163 } 164 165 vmbus_connection.recv_int_page = vmbus_connection.int_page; 166 vmbus_connection.send_int_page = 167 (void *)((unsigned long)vmbus_connection.int_page + 168 (PAGE_SIZE >> 1)); 169 170 /* 171 * Setup the monitor notification facility. The 1st page for 172 * parent->child and the 2nd page for child->parent 173 */ 174 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 175 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 176 if ((vmbus_connection.monitor_pages[0] == NULL) || 177 (vmbus_connection.monitor_pages[1] == NULL)) { 178 ret = -ENOMEM; 179 goto cleanup; 180 } 181 182 msginfo = kzalloc(sizeof(*msginfo) + 183 sizeof(struct vmbus_channel_initiate_contact), 184 GFP_KERNEL); 185 if (msginfo == NULL) { 186 ret = -ENOMEM; 187 goto cleanup; 188 } 189 190 /* 191 * Negotiate a compatible VMBUS version number with the 192 * host. We start with the highest number we can support 193 * and work our way down until we negotiate a compatible 194 * version. 195 */ 196 197 version = VERSION_CURRENT; 198 199 do { 200 ret = vmbus_negotiate_version(msginfo, version); 201 if (ret == -ETIMEDOUT) 202 goto cleanup; 203 204 if (vmbus_connection.conn_state == CONNECTED) 205 break; 206 207 version = vmbus_get_next_version(version); 208 } while (version != VERSION_INVAL); 209 210 if (version == VERSION_INVAL) 211 goto cleanup; 212 213 vmbus_proto_version = version; 214 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d; Vmbus version:%d.%d\n", 215 host_info_eax, host_info_ebx >> 16, 216 host_info_ebx & 0xFFFF, host_info_ecx, 217 host_info_edx >> 24, host_info_edx & 0xFFFFFF, 218 version >> 16, version & 0xFFFF); 219 220 kfree(msginfo); 221 return 0; 222 223 cleanup: 224 pr_err("Unable to connect to host\n"); 225 226 vmbus_connection.conn_state = DISCONNECTED; 227 vmbus_disconnect(); 228 229 kfree(msginfo); 230 231 return ret; 232 } 233 234 void vmbus_disconnect(void) 235 { 236 /* 237 * First send the unload request to the host. 238 */ 239 vmbus_initiate_unload(); 240 241 if (vmbus_connection.work_queue) { 242 drain_workqueue(vmbus_connection.work_queue); 243 destroy_workqueue(vmbus_connection.work_queue); 244 } 245 246 if (vmbus_connection.int_page) { 247 free_pages((unsigned long)vmbus_connection.int_page, 0); 248 vmbus_connection.int_page = NULL; 249 } 250 251 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0); 252 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0); 253 vmbus_connection.monitor_pages[0] = NULL; 254 vmbus_connection.monitor_pages[1] = NULL; 255 } 256 257 /* 258 * Map the given relid to the corresponding channel based on the 259 * per-cpu list of channels that have been affinitized to this CPU. 260 * This will be used in the channel callback path as we can do this 261 * mapping in a lock-free fashion. 262 */ 263 static struct vmbus_channel *pcpu_relid2channel(u32 relid) 264 { 265 struct vmbus_channel *channel; 266 struct vmbus_channel *found_channel = NULL; 267 int cpu = smp_processor_id(); 268 struct list_head *pcpu_head = &hv_context.percpu_list[cpu]; 269 270 list_for_each_entry(channel, pcpu_head, percpu_list) { 271 if (channel->offermsg.child_relid == relid) { 272 found_channel = channel; 273 break; 274 } 275 } 276 277 return found_channel; 278 } 279 280 /* 281 * relid2channel - Get the channel object given its 282 * child relative id (ie channel id) 283 */ 284 struct vmbus_channel *relid2channel(u32 relid) 285 { 286 struct vmbus_channel *channel; 287 struct vmbus_channel *found_channel = NULL; 288 struct list_head *cur, *tmp; 289 struct vmbus_channel *cur_sc; 290 291 mutex_lock(&vmbus_connection.channel_mutex); 292 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { 293 if (channel->offermsg.child_relid == relid) { 294 found_channel = channel; 295 break; 296 } else if (!list_empty(&channel->sc_list)) { 297 /* 298 * Deal with sub-channels. 299 */ 300 list_for_each_safe(cur, tmp, &channel->sc_list) { 301 cur_sc = list_entry(cur, struct vmbus_channel, 302 sc_list); 303 if (cur_sc->offermsg.child_relid == relid) { 304 found_channel = cur_sc; 305 break; 306 } 307 } 308 } 309 } 310 mutex_unlock(&vmbus_connection.channel_mutex); 311 312 return found_channel; 313 } 314 315 /* 316 * process_chn_event - Process a channel event notification 317 */ 318 static void process_chn_event(u32 relid) 319 { 320 struct vmbus_channel *channel; 321 void *arg; 322 bool read_state; 323 u32 bytes_to_read; 324 325 /* 326 * Find the channel based on this relid and invokes the 327 * channel callback to process the event 328 */ 329 channel = pcpu_relid2channel(relid); 330 331 if (!channel) 332 return; 333 334 /* 335 * A channel once created is persistent even when there 336 * is no driver handling the device. An unloading driver 337 * sets the onchannel_callback to NULL on the same CPU 338 * as where this interrupt is handled (in an interrupt context). 339 * Thus, checking and invoking the driver specific callback takes 340 * care of orderly unloading of the driver. 341 */ 342 343 if (channel->onchannel_callback != NULL) { 344 arg = channel->channel_callback_context; 345 read_state = channel->batched_reading; 346 /* 347 * This callback reads the messages sent by the host. 348 * We can optimize host to guest signaling by ensuring: 349 * 1. While reading the channel, we disable interrupts from 350 * host. 351 * 2. Ensure that we process all posted messages from the host 352 * before returning from this callback. 353 * 3. Once we return, enable signaling from the host. Once this 354 * state is set we check to see if additional packets are 355 * available to read. In this case we repeat the process. 356 */ 357 358 do { 359 if (read_state) 360 hv_begin_read(&channel->inbound); 361 channel->onchannel_callback(arg); 362 if (read_state) 363 bytes_to_read = hv_end_read(&channel->inbound); 364 else 365 bytes_to_read = 0; 366 } while (read_state && (bytes_to_read != 0)); 367 } 368 } 369 370 /* 371 * vmbus_on_event - Handler for events 372 */ 373 void vmbus_on_event(unsigned long data) 374 { 375 u32 dword; 376 u32 maxdword; 377 int bit; 378 u32 relid; 379 u32 *recv_int_page = NULL; 380 void *page_addr; 381 int cpu = smp_processor_id(); 382 union hv_synic_event_flags *event; 383 384 if (vmbus_proto_version < VERSION_WIN8) { 385 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5; 386 recv_int_page = vmbus_connection.recv_int_page; 387 } else { 388 /* 389 * When the host is win8 and beyond, the event page 390 * can be directly checked to get the id of the channel 391 * that has the interrupt pending. 392 */ 393 maxdword = HV_EVENT_FLAGS_DWORD_COUNT; 394 page_addr = hv_context.synic_event_page[cpu]; 395 event = (union hv_synic_event_flags *)page_addr + 396 VMBUS_MESSAGE_SINT; 397 recv_int_page = event->flags32; 398 } 399 400 401 402 /* Check events */ 403 if (!recv_int_page) 404 return; 405 for (dword = 0; dword < maxdword; dword++) { 406 if (!recv_int_page[dword]) 407 continue; 408 for (bit = 0; bit < 32; bit++) { 409 if (sync_test_and_clear_bit(bit, 410 (unsigned long *)&recv_int_page[dword])) { 411 relid = (dword << 5) + bit; 412 413 if (relid == 0) 414 /* 415 * Special case - vmbus 416 * channel protocol msg 417 */ 418 continue; 419 420 process_chn_event(relid); 421 } 422 } 423 } 424 } 425 426 /* 427 * vmbus_post_msg - Send a msg on the vmbus's message connection 428 */ 429 int vmbus_post_msg(void *buffer, size_t buflen) 430 { 431 union hv_connection_id conn_id; 432 int ret = 0; 433 int retries = 0; 434 u32 msec = 1; 435 436 conn_id.asu32 = 0; 437 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID; 438 439 /* 440 * hv_post_message() can have transient failures because of 441 * insufficient resources. Retry the operation a couple of 442 * times before giving up. 443 */ 444 while (retries < 20) { 445 ret = hv_post_message(conn_id, 1, buffer, buflen); 446 447 switch (ret) { 448 case HV_STATUS_INVALID_CONNECTION_ID: 449 /* 450 * We could get this if we send messages too 451 * frequently. 452 */ 453 ret = -EAGAIN; 454 break; 455 case HV_STATUS_INSUFFICIENT_MEMORY: 456 case HV_STATUS_INSUFFICIENT_BUFFERS: 457 ret = -ENOMEM; 458 break; 459 case HV_STATUS_SUCCESS: 460 return ret; 461 default: 462 pr_err("hv_post_msg() failed; error code:%d\n", ret); 463 return -EINVAL; 464 } 465 466 retries++; 467 msleep(msec); 468 if (msec < 2048) 469 msec *= 2; 470 } 471 return ret; 472 } 473 474 /* 475 * vmbus_set_event - Send an event notification to the parent 476 */ 477 int vmbus_set_event(struct vmbus_channel *channel) 478 { 479 u32 child_relid = channel->offermsg.child_relid; 480 481 if (!channel->is_dedicated_interrupt) { 482 /* Each u32 represents 32 channels */ 483 sync_set_bit(child_relid & 31, 484 (unsigned long *)vmbus_connection.send_int_page + 485 (child_relid >> 5)); 486 } 487 488 return hv_signal_event(channel->sig_event); 489 } 490