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 * 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 */ 142 int 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; 230 231 cleanup: 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 } 241 242 void 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 */ 271 static 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 */ 292 struct 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 */ 326 static 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 */ 381 void 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 */ 437 int 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 usec = 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 udelay(usec); 476 if (usec < 2048) 477 usec *= 2; 478 } 479 return ret; 480 } 481 482 /* 483 * vmbus_set_event - Send an event notification to the parent 484 */ 485 void 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 } 498 EXPORT_SYMBOL_GPL(vmbus_set_event); 499