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 if (version >= VERSION_WIN8_1) { 87 msg->target_vcpu = hv_context.vp_index[get_cpu()]; 88 put_cpu(); 89 } 90 91 /* 92 * Add to list before we send the request since we may 93 * receive the response before returning from this routine 94 */ 95 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 96 list_add_tail(&msginfo->msglistentry, 97 &vmbus_connection.chn_msg_list); 98 99 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 100 101 ret = vmbus_post_msg(msg, 102 sizeof(struct vmbus_channel_initiate_contact)); 103 if (ret != 0) { 104 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 105 list_del(&msginfo->msglistentry); 106 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, 107 flags); 108 return ret; 109 } 110 111 /* Wait for the connection response */ 112 wait_for_completion(&msginfo->waitevent); 113 114 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 115 list_del(&msginfo->msglistentry); 116 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 117 118 /* Check if successful */ 119 if (msginfo->response.version_response.version_supported) { 120 vmbus_connection.conn_state = CONNECTED; 121 } else { 122 return -ECONNREFUSED; 123 } 124 125 return ret; 126 } 127 128 /* 129 * vmbus_connect - Sends a connect request on the partition service connection 130 */ 131 int vmbus_connect(void) 132 { 133 int ret = 0; 134 struct vmbus_channel_msginfo *msginfo = NULL; 135 __u32 version; 136 137 /* Initialize the vmbus connection */ 138 vmbus_connection.conn_state = CONNECTING; 139 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con"); 140 if (!vmbus_connection.work_queue) { 141 ret = -ENOMEM; 142 goto cleanup; 143 } 144 145 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list); 146 spin_lock_init(&vmbus_connection.channelmsg_lock); 147 148 INIT_LIST_HEAD(&vmbus_connection.chn_list); 149 spin_lock_init(&vmbus_connection.channel_lock); 150 151 /* 152 * Setup the vmbus event connection for channel interrupt 153 * abstraction stuff 154 */ 155 vmbus_connection.int_page = 156 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0); 157 if (vmbus_connection.int_page == NULL) { 158 ret = -ENOMEM; 159 goto cleanup; 160 } 161 162 vmbus_connection.recv_int_page = vmbus_connection.int_page; 163 vmbus_connection.send_int_page = 164 (void *)((unsigned long)vmbus_connection.int_page + 165 (PAGE_SIZE >> 1)); 166 167 /* 168 * Setup the monitor notification facility. The 1st page for 169 * parent->child and the 2nd page for child->parent 170 */ 171 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 172 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 173 if ((vmbus_connection.monitor_pages[0] == NULL) || 174 (vmbus_connection.monitor_pages[1] == NULL)) { 175 ret = -ENOMEM; 176 goto cleanup; 177 } 178 179 msginfo = kzalloc(sizeof(*msginfo) + 180 sizeof(struct vmbus_channel_initiate_contact), 181 GFP_KERNEL); 182 if (msginfo == NULL) { 183 ret = -ENOMEM; 184 goto cleanup; 185 } 186 187 /* 188 * Negotiate a compatible VMBUS version number with the 189 * host. We start with the highest number we can support 190 * and work our way down until we negotiate a compatible 191 * version. 192 */ 193 194 version = VERSION_CURRENT; 195 196 do { 197 ret = vmbus_negotiate_version(msginfo, version); 198 if (ret == -ETIMEDOUT) 199 goto cleanup; 200 201 if (vmbus_connection.conn_state == CONNECTED) 202 break; 203 204 version = vmbus_get_next_version(version); 205 } while (version != VERSION_INVAL); 206 207 if (version == VERSION_INVAL) 208 goto cleanup; 209 210 vmbus_proto_version = version; 211 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d; Vmbus version:%d.%d\n", 212 host_info_eax, host_info_ebx >> 16, 213 host_info_ebx & 0xFFFF, host_info_ecx, 214 host_info_edx >> 24, host_info_edx & 0xFFFFFF, 215 version >> 16, version & 0xFFFF); 216 217 kfree(msginfo); 218 return 0; 219 220 cleanup: 221 pr_err("Unable to connect to host\n"); 222 223 vmbus_connection.conn_state = DISCONNECTED; 224 vmbus_disconnect(); 225 226 kfree(msginfo); 227 228 return ret; 229 } 230 231 void vmbus_disconnect(void) 232 { 233 /* 234 * First send the unload request to the host. 235 */ 236 vmbus_initiate_unload(); 237 238 if (vmbus_connection.work_queue) { 239 drain_workqueue(vmbus_connection.work_queue); 240 destroy_workqueue(vmbus_connection.work_queue); 241 } 242 243 if (vmbus_connection.int_page) { 244 free_pages((unsigned long)vmbus_connection.int_page, 0); 245 vmbus_connection.int_page = NULL; 246 } 247 248 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0); 249 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0); 250 vmbus_connection.monitor_pages[0] = NULL; 251 vmbus_connection.monitor_pages[1] = NULL; 252 } 253 254 /* 255 * Map the given relid to the corresponding channel based on the 256 * per-cpu list of channels that have been affinitized to this CPU. 257 * This will be used in the channel callback path as we can do this 258 * mapping in a lock-free fashion. 259 */ 260 static struct vmbus_channel *pcpu_relid2channel(u32 relid) 261 { 262 struct vmbus_channel *channel; 263 struct vmbus_channel *found_channel = NULL; 264 int cpu = smp_processor_id(); 265 struct list_head *pcpu_head = &hv_context.percpu_list[cpu]; 266 267 list_for_each_entry(channel, pcpu_head, percpu_list) { 268 if (channel->offermsg.child_relid == relid) { 269 found_channel = channel; 270 break; 271 } 272 } 273 274 return found_channel; 275 } 276 277 /* 278 * relid2channel - Get the channel object given its 279 * child relative id (ie channel id) 280 */ 281 struct vmbus_channel *relid2channel(u32 relid) 282 { 283 struct vmbus_channel *channel; 284 struct vmbus_channel *found_channel = NULL; 285 unsigned long flags; 286 struct list_head *cur, *tmp; 287 struct vmbus_channel *cur_sc; 288 289 spin_lock_irqsave(&vmbus_connection.channel_lock, flags); 290 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { 291 if (channel->offermsg.child_relid == relid) { 292 found_channel = channel; 293 break; 294 } else if (!list_empty(&channel->sc_list)) { 295 /* 296 * Deal with sub-channels. 297 */ 298 list_for_each_safe(cur, tmp, &channel->sc_list) { 299 cur_sc = list_entry(cur, struct vmbus_channel, 300 sc_list); 301 if (cur_sc->offermsg.child_relid == relid) { 302 found_channel = cur_sc; 303 break; 304 } 305 } 306 } 307 } 308 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags); 309 310 return found_channel; 311 } 312 313 /* 314 * process_chn_event - Process a channel event notification 315 */ 316 static void process_chn_event(u32 relid) 317 { 318 struct vmbus_channel *channel; 319 void *arg; 320 bool read_state; 321 u32 bytes_to_read; 322 323 /* 324 * Find the channel based on this relid and invokes the 325 * channel callback to process the event 326 */ 327 channel = pcpu_relid2channel(relid); 328 329 if (!channel) 330 return; 331 332 /* 333 * A channel once created is persistent even when there 334 * is no driver handling the device. An unloading driver 335 * sets the onchannel_callback to NULL on the same CPU 336 * as where this interrupt is handled (in an interrupt context). 337 * Thus, checking and invoking the driver specific callback takes 338 * care of orderly unloading of the driver. 339 */ 340 341 if (channel->onchannel_callback != NULL) { 342 arg = channel->channel_callback_context; 343 read_state = channel->batched_reading; 344 /* 345 * This callback reads the messages sent by the host. 346 * We can optimize host to guest signaling by ensuring: 347 * 1. While reading the channel, we disable interrupts from 348 * host. 349 * 2. Ensure that we process all posted messages from the host 350 * before returning from this callback. 351 * 3. Once we return, enable signaling from the host. Once this 352 * state is set we check to see if additional packets are 353 * available to read. In this case we repeat the process. 354 */ 355 356 do { 357 if (read_state) 358 hv_begin_read(&channel->inbound); 359 channel->onchannel_callback(arg); 360 if (read_state) 361 bytes_to_read = hv_end_read(&channel->inbound); 362 else 363 bytes_to_read = 0; 364 } while (read_state && (bytes_to_read != 0)); 365 } 366 } 367 368 /* 369 * vmbus_on_event - Handler for events 370 */ 371 void vmbus_on_event(unsigned long data) 372 { 373 u32 dword; 374 u32 maxdword; 375 int bit; 376 u32 relid; 377 u32 *recv_int_page = NULL; 378 void *page_addr; 379 int cpu = smp_processor_id(); 380 union hv_synic_event_flags *event; 381 382 if (vmbus_proto_version < VERSION_WIN8) { 383 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5; 384 recv_int_page = vmbus_connection.recv_int_page; 385 } else { 386 /* 387 * When the host is win8 and beyond, the event page 388 * can be directly checked to get the id of the channel 389 * that has the interrupt pending. 390 */ 391 maxdword = HV_EVENT_FLAGS_DWORD_COUNT; 392 page_addr = hv_context.synic_event_page[cpu]; 393 event = (union hv_synic_event_flags *)page_addr + 394 VMBUS_MESSAGE_SINT; 395 recv_int_page = event->flags32; 396 } 397 398 399 400 /* Check events */ 401 if (!recv_int_page) 402 return; 403 for (dword = 0; dword < maxdword; dword++) { 404 if (!recv_int_page[dword]) 405 continue; 406 for (bit = 0; bit < 32; bit++) { 407 if (sync_test_and_clear_bit(bit, 408 (unsigned long *)&recv_int_page[dword])) { 409 relid = (dword << 5) + bit; 410 411 if (relid == 0) 412 /* 413 * Special case - vmbus 414 * channel protocol msg 415 */ 416 continue; 417 418 process_chn_event(relid); 419 } 420 } 421 } 422 } 423 424 /* 425 * vmbus_post_msg - Send a msg on the vmbus's message connection 426 */ 427 int vmbus_post_msg(void *buffer, size_t buflen) 428 { 429 union hv_connection_id conn_id; 430 int ret = 0; 431 int retries = 0; 432 u32 msec = 1; 433 434 conn_id.asu32 = 0; 435 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID; 436 437 /* 438 * hv_post_message() can have transient failures because of 439 * insufficient resources. Retry the operation a couple of 440 * times before giving up. 441 */ 442 while (retries < 20) { 443 ret = hv_post_message(conn_id, 1, buffer, buflen); 444 445 switch (ret) { 446 case HV_STATUS_INVALID_CONNECTION_ID: 447 /* 448 * We could get this if we send messages too 449 * frequently. 450 */ 451 ret = -EAGAIN; 452 break; 453 case HV_STATUS_INSUFFICIENT_MEMORY: 454 case HV_STATUS_INSUFFICIENT_BUFFERS: 455 ret = -ENOMEM; 456 break; 457 case HV_STATUS_SUCCESS: 458 return ret; 459 default: 460 pr_err("hv_post_msg() failed; error code:%d\n", ret); 461 return -EINVAL; 462 } 463 464 retries++; 465 msleep(msec); 466 if (msec < 2048) 467 msec *= 2; 468 } 469 return ret; 470 } 471 472 /* 473 * vmbus_set_event - Send an event notification to the parent 474 */ 475 int vmbus_set_event(struct vmbus_channel *channel) 476 { 477 u32 child_relid = channel->offermsg.child_relid; 478 479 if (!channel->is_dedicated_interrupt) { 480 /* Each u32 represents 32 channels */ 481 sync_set_bit(child_relid & 31, 482 (unsigned long *)vmbus_connection.send_int_page + 483 (child_relid >> 5)); 484 } 485 486 return hv_signal_event(channel->sig_event); 487 } 488