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 EXPORT_SYMBOL_GPL(vmbus_connection); 43 44 /* 45 * Negotiated protocol version with the host. 46 */ 47 __u32 vmbus_proto_version; 48 EXPORT_SYMBOL_GPL(vmbus_proto_version); 49 50 static __u32 vmbus_get_next_version(__u32 current_version) 51 { 52 switch (current_version) { 53 case (VERSION_WIN7): 54 return VERSION_WS2008; 55 56 case (VERSION_WIN8): 57 return VERSION_WIN7; 58 59 case (VERSION_WIN8_1): 60 return VERSION_WIN8; 61 62 case (VERSION_WIN10): 63 return VERSION_WIN8_1; 64 65 case (VERSION_WS2008): 66 default: 67 return VERSION_INVAL; 68 } 69 } 70 71 static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, 72 __u32 version) 73 { 74 int ret = 0; 75 struct vmbus_channel_initiate_contact *msg; 76 unsigned long flags; 77 78 init_completion(&msginfo->waitevent); 79 80 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg; 81 82 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT; 83 msg->vmbus_version_requested = version; 84 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page); 85 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]); 86 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]); 87 /* 88 * We want all channel messages to be delivered on CPU 0. 89 * This has been the behavior pre-win8. This is not 90 * perf issue and having all channel messages delivered on CPU 0 91 * would be ok. 92 * For post win8 hosts, we support receiving channel messagges on 93 * all the CPUs. This is needed for kexec to work correctly where 94 * the CPU attempting to connect may not be CPU 0. 95 */ 96 if (version >= VERSION_WIN8_1) { 97 msg->target_vcpu = hv_context.vp_index[get_cpu()]; 98 put_cpu(); 99 } else { 100 msg->target_vcpu = 0; 101 } 102 103 /* 104 * Add to list before we send the request since we may 105 * receive the response before returning from this routine 106 */ 107 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 108 list_add_tail(&msginfo->msglistentry, 109 &vmbus_connection.chn_msg_list); 110 111 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 112 113 ret = vmbus_post_msg(msg, 114 sizeof(struct vmbus_channel_initiate_contact), 115 true); 116 if (ret != 0) { 117 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 118 list_del(&msginfo->msglistentry); 119 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, 120 flags); 121 return ret; 122 } 123 124 /* Wait for the connection response */ 125 wait_for_completion(&msginfo->waitevent); 126 127 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 128 list_del(&msginfo->msglistentry); 129 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 130 131 /* Check if successful */ 132 if (msginfo->response.version_response.version_supported) { 133 vmbus_connection.conn_state = CONNECTED; 134 } else { 135 return -ECONNREFUSED; 136 } 137 138 return ret; 139 } 140 141 /* 142 * vmbus_connect - Sends a connect request on the partition service connection 143 */ 144 int vmbus_connect(void) 145 { 146 int ret = 0; 147 struct vmbus_channel_msginfo *msginfo = NULL; 148 __u32 version; 149 150 /* Initialize the vmbus connection */ 151 vmbus_connection.conn_state = CONNECTING; 152 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con"); 153 if (!vmbus_connection.work_queue) { 154 ret = -ENOMEM; 155 goto cleanup; 156 } 157 158 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list); 159 spin_lock_init(&vmbus_connection.channelmsg_lock); 160 161 INIT_LIST_HEAD(&vmbus_connection.chn_list); 162 mutex_init(&vmbus_connection.channel_mutex); 163 164 /* 165 * Setup the vmbus event connection for channel interrupt 166 * abstraction stuff 167 */ 168 vmbus_connection.int_page = 169 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0); 170 if (vmbus_connection.int_page == NULL) { 171 ret = -ENOMEM; 172 goto cleanup; 173 } 174 175 vmbus_connection.recv_int_page = vmbus_connection.int_page; 176 vmbus_connection.send_int_page = 177 (void *)((unsigned long)vmbus_connection.int_page + 178 (PAGE_SIZE >> 1)); 179 180 /* 181 * Setup the monitor notification facility. The 1st page for 182 * parent->child and the 2nd page for child->parent 183 */ 184 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 185 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 186 if ((vmbus_connection.monitor_pages[0] == NULL) || 187 (vmbus_connection.monitor_pages[1] == NULL)) { 188 ret = -ENOMEM; 189 goto cleanup; 190 } 191 192 msginfo = kzalloc(sizeof(*msginfo) + 193 sizeof(struct vmbus_channel_initiate_contact), 194 GFP_KERNEL); 195 if (msginfo == NULL) { 196 ret = -ENOMEM; 197 goto cleanup; 198 } 199 200 /* 201 * Negotiate a compatible VMBUS version number with the 202 * host. We start with the highest number we can support 203 * and work our way down until we negotiate a compatible 204 * version. 205 */ 206 207 version = VERSION_CURRENT; 208 209 do { 210 ret = vmbus_negotiate_version(msginfo, version); 211 if (ret == -ETIMEDOUT) 212 goto cleanup; 213 214 if (vmbus_connection.conn_state == CONNECTED) 215 break; 216 217 version = vmbus_get_next_version(version); 218 } while (version != VERSION_INVAL); 219 220 if (version == VERSION_INVAL) 221 goto cleanup; 222 223 vmbus_proto_version = version; 224 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d; Vmbus version:%d.%d\n", 225 host_info_eax, host_info_ebx >> 16, 226 host_info_ebx & 0xFFFF, host_info_ecx, 227 host_info_edx >> 24, host_info_edx & 0xFFFFFF, 228 version >> 16, version & 0xFFFF); 229 230 kfree(msginfo); 231 return 0; 232 233 cleanup: 234 pr_err("Unable to connect to host\n"); 235 236 vmbus_connection.conn_state = DISCONNECTED; 237 vmbus_disconnect(); 238 239 kfree(msginfo); 240 241 return ret; 242 } 243 244 void vmbus_disconnect(void) 245 { 246 /* 247 * First send the unload request to the host. 248 */ 249 vmbus_initiate_unload(false); 250 251 if (vmbus_connection.work_queue) { 252 drain_workqueue(vmbus_connection.work_queue); 253 destroy_workqueue(vmbus_connection.work_queue); 254 } 255 256 if (vmbus_connection.int_page) { 257 free_pages((unsigned long)vmbus_connection.int_page, 0); 258 vmbus_connection.int_page = NULL; 259 } 260 261 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0); 262 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0); 263 vmbus_connection.monitor_pages[0] = NULL; 264 vmbus_connection.monitor_pages[1] = NULL; 265 } 266 267 /* 268 * Map the given relid to the corresponding channel based on the 269 * per-cpu list of channels that have been affinitized to this CPU. 270 * This will be used in the channel callback path as we can do this 271 * mapping in a lock-free fashion. 272 */ 273 static struct vmbus_channel *pcpu_relid2channel(u32 relid) 274 { 275 struct vmbus_channel *channel; 276 struct vmbus_channel *found_channel = NULL; 277 int cpu = smp_processor_id(); 278 struct list_head *pcpu_head = &hv_context.percpu_list[cpu]; 279 280 list_for_each_entry(channel, pcpu_head, percpu_list) { 281 if (channel->offermsg.child_relid == relid) { 282 found_channel = channel; 283 break; 284 } 285 } 286 287 return found_channel; 288 } 289 290 /* 291 * relid2channel - Get the channel object given its 292 * child relative id (ie channel id) 293 */ 294 struct vmbus_channel *relid2channel(u32 relid) 295 { 296 struct vmbus_channel *channel; 297 struct vmbus_channel *found_channel = NULL; 298 struct list_head *cur, *tmp; 299 struct vmbus_channel *cur_sc; 300 301 BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex)); 302 303 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { 304 if (channel->offermsg.child_relid == relid) { 305 found_channel = channel; 306 break; 307 } else if (!list_empty(&channel->sc_list)) { 308 /* 309 * Deal with sub-channels. 310 */ 311 list_for_each_safe(cur, tmp, &channel->sc_list) { 312 cur_sc = list_entry(cur, struct vmbus_channel, 313 sc_list); 314 if (cur_sc->offermsg.child_relid == relid) { 315 found_channel = cur_sc; 316 break; 317 } 318 } 319 } 320 } 321 322 return found_channel; 323 } 324 325 /* 326 * process_chn_event - Process a channel event notification 327 */ 328 static void process_chn_event(u32 relid) 329 { 330 struct vmbus_channel *channel; 331 void *arg; 332 bool read_state; 333 u32 bytes_to_read; 334 335 /* 336 * Find the channel based on this relid and invokes the 337 * channel callback to process the event 338 */ 339 channel = pcpu_relid2channel(relid); 340 341 if (!channel) 342 return; 343 344 /* 345 * A channel once created is persistent even when there 346 * is no driver handling the device. An unloading driver 347 * sets the onchannel_callback to NULL on the same CPU 348 * as where this interrupt is handled (in an interrupt context). 349 * Thus, checking and invoking the driver specific callback takes 350 * care of orderly unloading of the driver. 351 */ 352 353 if (channel->onchannel_callback != NULL) { 354 arg = channel->channel_callback_context; 355 read_state = channel->batched_reading; 356 /* 357 * This callback reads the messages sent by the host. 358 * We can optimize host to guest signaling by ensuring: 359 * 1. While reading the channel, we disable interrupts from 360 * host. 361 * 2. Ensure that we process all posted messages from the host 362 * before returning from this callback. 363 * 3. Once we return, enable signaling from the host. Once this 364 * state is set we check to see if additional packets are 365 * available to read. In this case we repeat the process. 366 */ 367 368 do { 369 if (read_state) 370 hv_begin_read(&channel->inbound); 371 channel->onchannel_callback(arg); 372 if (read_state) 373 bytes_to_read = hv_end_read(&channel->inbound); 374 else 375 bytes_to_read = 0; 376 } while (read_state && (bytes_to_read != 0)); 377 } 378 } 379 380 /* 381 * vmbus_on_event - Handler for events 382 */ 383 void vmbus_on_event(unsigned long data) 384 { 385 u32 dword; 386 u32 maxdword; 387 int bit; 388 u32 relid; 389 u32 *recv_int_page = NULL; 390 void *page_addr; 391 int cpu = smp_processor_id(); 392 union hv_synic_event_flags *event; 393 394 if (vmbus_proto_version < VERSION_WIN8) { 395 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5; 396 recv_int_page = vmbus_connection.recv_int_page; 397 } else { 398 /* 399 * When the host is win8 and beyond, the event page 400 * can be directly checked to get the id of the channel 401 * that has the interrupt pending. 402 */ 403 maxdword = HV_EVENT_FLAGS_DWORD_COUNT; 404 page_addr = hv_context.synic_event_page[cpu]; 405 event = (union hv_synic_event_flags *)page_addr + 406 VMBUS_MESSAGE_SINT; 407 recv_int_page = event->flags32; 408 } 409 410 411 412 /* Check events */ 413 if (!recv_int_page) 414 return; 415 for (dword = 0; dword < maxdword; dword++) { 416 if (!recv_int_page[dword]) 417 continue; 418 for (bit = 0; bit < 32; bit++) { 419 if (sync_test_and_clear_bit(bit, 420 (unsigned long *)&recv_int_page[dword])) { 421 relid = (dword << 5) + bit; 422 423 if (relid == 0) 424 /* 425 * Special case - vmbus 426 * channel protocol msg 427 */ 428 continue; 429 430 process_chn_event(relid); 431 } 432 } 433 } 434 } 435 436 /* 437 * vmbus_post_msg - Send a msg on the vmbus's message connection 438 */ 439 int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep) 440 { 441 union hv_connection_id conn_id; 442 int ret = 0; 443 int retries = 0; 444 u32 usec = 1; 445 446 conn_id.asu32 = 0; 447 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID; 448 449 /* 450 * hv_post_message() can have transient failures because of 451 * insufficient resources. Retry the operation a couple of 452 * times before giving up. 453 */ 454 while (retries < 100) { 455 ret = hv_post_message(conn_id, 1, buffer, buflen); 456 457 switch (ret) { 458 case HV_STATUS_INVALID_CONNECTION_ID: 459 /* 460 * We could get this if we send messages too 461 * frequently. 462 */ 463 ret = -EAGAIN; 464 break; 465 case HV_STATUS_INSUFFICIENT_MEMORY: 466 case HV_STATUS_INSUFFICIENT_BUFFERS: 467 ret = -ENOMEM; 468 break; 469 case HV_STATUS_SUCCESS: 470 return ret; 471 default: 472 pr_err("hv_post_msg() failed; error code:%d\n", ret); 473 return -EINVAL; 474 } 475 476 retries++; 477 if (can_sleep && usec > 1000) 478 msleep(usec / 1000); 479 else if (usec < MAX_UDELAY_MS * 1000) 480 udelay(usec); 481 else 482 mdelay(usec / 1000); 483 484 if (usec < 256000) 485 usec *= 2; 486 } 487 return ret; 488 } 489 490 /* 491 * vmbus_set_event - Send an event notification to the parent 492 */ 493 void vmbus_set_event(struct vmbus_channel *channel) 494 { 495 u32 child_relid = channel->offermsg.child_relid; 496 497 if (!channel->is_dedicated_interrupt) { 498 /* Each u32 represents 32 channels */ 499 sync_set_bit(child_relid & 31, 500 (unsigned long *)vmbus_connection.send_int_page + 501 (child_relid >> 5)); 502 } 503 504 hv_do_hypercall(HVCALL_SIGNAL_EVENT, channel->sig_event, NULL); 505 } 506 EXPORT_SYMBOL_GPL(vmbus_set_event); 507