connection.c revision fdeebcc62279119dbeafbc1a2e39e773839025fd
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 38struct 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; 47EXPORT_SYMBOL_GPL(vmbus_proto_version); 48 49static __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_WS2008): 62 default: 63 return VERSION_INVAL; 64 } 65} 66 67static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, 68 __u32 version) 69{ 70 int ret = 0; 71 struct vmbus_channel_initiate_contact *msg; 72 unsigned long flags; 73 74 init_completion(&msginfo->waitevent); 75 76 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg; 77 78 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT; 79 msg->vmbus_version_requested = version; 80 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page); 81 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]); 82 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]); 83 if (version == VERSION_WIN8_1) 84 msg->target_vcpu = hv_context.vp_index[smp_processor_id()]; 85 86 /* 87 * Add to list before we send the request since we may 88 * receive the response before returning from this routine 89 */ 90 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 91 list_add_tail(&msginfo->msglistentry, 92 &vmbus_connection.chn_msg_list); 93 94 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 95 96 ret = vmbus_post_msg(msg, 97 sizeof(struct vmbus_channel_initiate_contact)); 98 if (ret != 0) { 99 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 100 list_del(&msginfo->msglistentry); 101 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, 102 flags); 103 return ret; 104 } 105 106 /* Wait for the connection response */ 107 wait_for_completion(&msginfo->waitevent); 108 109 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 110 list_del(&msginfo->msglistentry); 111 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 112 113 /* Check if successful */ 114 if (msginfo->response.version_response.version_supported) { 115 vmbus_connection.conn_state = CONNECTED; 116 } else { 117 return -ECONNREFUSED; 118 } 119 120 return ret; 121} 122 123/* 124 * vmbus_connect - Sends a connect request on the partition service connection 125 */ 126int vmbus_connect(void) 127{ 128 int ret = 0; 129 struct vmbus_channel_msginfo *msginfo = NULL; 130 __u32 version; 131 132 /* Initialize the vmbus connection */ 133 vmbus_connection.conn_state = CONNECTING; 134 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con"); 135 if (!vmbus_connection.work_queue) { 136 ret = -ENOMEM; 137 goto cleanup; 138 } 139 140 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list); 141 spin_lock_init(&vmbus_connection.channelmsg_lock); 142 143 INIT_LIST_HEAD(&vmbus_connection.chn_list); 144 spin_lock_init(&vmbus_connection.channel_lock); 145 146 /* 147 * Setup the vmbus event connection for channel interrupt 148 * abstraction stuff 149 */ 150 vmbus_connection.int_page = 151 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0); 152 if (vmbus_connection.int_page == NULL) { 153 ret = -ENOMEM; 154 goto cleanup; 155 } 156 157 vmbus_connection.recv_int_page = vmbus_connection.int_page; 158 vmbus_connection.send_int_page = 159 (void *)((unsigned long)vmbus_connection.int_page + 160 (PAGE_SIZE >> 1)); 161 162 /* 163 * Setup the monitor notification facility. The 1st page for 164 * parent->child and the 2nd page for child->parent 165 */ 166 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 167 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 168 if ((vmbus_connection.monitor_pages[0] == NULL) || 169 (vmbus_connection.monitor_pages[1] == NULL)) { 170 ret = -ENOMEM; 171 goto cleanup; 172 } 173 174 msginfo = kzalloc(sizeof(*msginfo) + 175 sizeof(struct vmbus_channel_initiate_contact), 176 GFP_KERNEL); 177 if (msginfo == NULL) { 178 ret = -ENOMEM; 179 goto cleanup; 180 } 181 182 /* 183 * Negotiate a compatible VMBUS version number with the 184 * host. We start with the highest number we can support 185 * and work our way down until we negotiate a compatible 186 * version. 187 */ 188 189 version = VERSION_CURRENT; 190 191 do { 192 ret = vmbus_negotiate_version(msginfo, version); 193 if (ret == -ETIMEDOUT) 194 goto cleanup; 195 196 if (vmbus_connection.conn_state == CONNECTED) 197 break; 198 199 version = vmbus_get_next_version(version); 200 } while (version != VERSION_INVAL); 201 202 if (version == VERSION_INVAL) 203 goto cleanup; 204 205 vmbus_proto_version = version; 206 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d; Vmbus version:%d.%d\n", 207 host_info_eax, host_info_ebx >> 16, 208 host_info_ebx & 0xFFFF, host_info_ecx, 209 host_info_edx >> 24, host_info_edx & 0xFFFFFF, 210 version >> 16, version & 0xFFFF); 211 212 kfree(msginfo); 213 return 0; 214 215cleanup: 216 pr_err("Unable to connect to host\n"); 217 vmbus_connection.conn_state = DISCONNECTED; 218 219 if (vmbus_connection.work_queue) 220 destroy_workqueue(vmbus_connection.work_queue); 221 222 if (vmbus_connection.int_page) { 223 free_pages((unsigned long)vmbus_connection.int_page, 0); 224 vmbus_connection.int_page = NULL; 225 } 226 227 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0); 228 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0); 229 vmbus_connection.monitor_pages[0] = NULL; 230 vmbus_connection.monitor_pages[1] = NULL; 231 232 kfree(msginfo); 233 234 return ret; 235} 236 237/* 238 * Map the given relid to the corresponding channel based on the 239 * per-cpu list of channels that have been affinitized to this CPU. 240 * This will be used in the channel callback path as we can do this 241 * mapping in a lock-free fashion. 242 */ 243static struct vmbus_channel *pcpu_relid2channel(u32 relid) 244{ 245 struct vmbus_channel *channel; 246 struct vmbus_channel *found_channel = NULL; 247 int cpu = smp_processor_id(); 248 struct list_head *pcpu_head = &hv_context.percpu_list[cpu]; 249 250 list_for_each_entry(channel, pcpu_head, percpu_list) { 251 if (channel->offermsg.child_relid == relid) { 252 found_channel = channel; 253 break; 254 } 255 } 256 257 return found_channel; 258} 259 260/* 261 * relid2channel - Get the channel object given its 262 * child relative id (ie channel id) 263 */ 264struct vmbus_channel *relid2channel(u32 relid) 265{ 266 struct vmbus_channel *channel; 267 struct vmbus_channel *found_channel = NULL; 268 unsigned long flags; 269 struct list_head *cur, *tmp; 270 struct vmbus_channel *cur_sc; 271 272 spin_lock_irqsave(&vmbus_connection.channel_lock, flags); 273 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { 274 if (channel->offermsg.child_relid == relid) { 275 found_channel = channel; 276 break; 277 } else if (!list_empty(&channel->sc_list)) { 278 /* 279 * Deal with sub-channels. 280 */ 281 list_for_each_safe(cur, tmp, &channel->sc_list) { 282 cur_sc = list_entry(cur, struct vmbus_channel, 283 sc_list); 284 if (cur_sc->offermsg.child_relid == relid) { 285 found_channel = cur_sc; 286 break; 287 } 288 } 289 } 290 } 291 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags); 292 293 return found_channel; 294} 295 296/* 297 * process_chn_event - Process a channel event notification 298 */ 299static void process_chn_event(u32 relid) 300{ 301 struct vmbus_channel *channel; 302 void *arg; 303 bool read_state; 304 u32 bytes_to_read; 305 306 /* 307 * Find the channel based on this relid and invokes the 308 * channel callback to process the event 309 */ 310 channel = pcpu_relid2channel(relid); 311 312 if (!channel) { 313 pr_err("channel not found for relid - %u\n", relid); 314 return; 315 } 316 317 /* 318 * A channel once created is persistent even when there 319 * is no driver handling the device. An unloading driver 320 * sets the onchannel_callback to NULL on the same CPU 321 * as where this interrupt is handled (in an interrupt context). 322 * Thus, checking and invoking the driver specific callback takes 323 * care of orderly unloading of the driver. 324 */ 325 326 if (channel->onchannel_callback != NULL) { 327 arg = channel->channel_callback_context; 328 read_state = channel->batched_reading; 329 /* 330 * This callback reads the messages sent by the host. 331 * We can optimize host to guest signaling by ensuring: 332 * 1. While reading the channel, we disable interrupts from 333 * host. 334 * 2. Ensure that we process all posted messages from the host 335 * before returning from this callback. 336 * 3. Once we return, enable signaling from the host. Once this 337 * state is set we check to see if additional packets are 338 * available to read. In this case we repeat the process. 339 */ 340 341 do { 342 if (read_state) 343 hv_begin_read(&channel->inbound); 344 channel->onchannel_callback(arg); 345 if (read_state) 346 bytes_to_read = hv_end_read(&channel->inbound); 347 else 348 bytes_to_read = 0; 349 } while (read_state && (bytes_to_read != 0)); 350 } else { 351 pr_err("no channel callback for relid - %u\n", relid); 352 } 353 354} 355 356/* 357 * vmbus_on_event - Handler for events 358 */ 359void vmbus_on_event(unsigned long data) 360{ 361 u32 dword; 362 u32 maxdword; 363 int bit; 364 u32 relid; 365 u32 *recv_int_page = NULL; 366 void *page_addr; 367 int cpu = smp_processor_id(); 368 union hv_synic_event_flags *event; 369 370 if ((vmbus_proto_version == VERSION_WS2008) || 371 (vmbus_proto_version == VERSION_WIN7)) { 372 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5; 373 recv_int_page = vmbus_connection.recv_int_page; 374 } else { 375 /* 376 * When the host is win8 and beyond, the event page 377 * can be directly checked to get the id of the channel 378 * that has the interrupt pending. 379 */ 380 maxdword = HV_EVENT_FLAGS_DWORD_COUNT; 381 page_addr = hv_context.synic_event_page[cpu]; 382 event = (union hv_synic_event_flags *)page_addr + 383 VMBUS_MESSAGE_SINT; 384 recv_int_page = event->flags32; 385 } 386 387 388 389 /* Check events */ 390 if (!recv_int_page) 391 return; 392 for (dword = 0; dword < maxdword; dword++) { 393 if (!recv_int_page[dword]) 394 continue; 395 for (bit = 0; bit < 32; bit++) { 396 if (sync_test_and_clear_bit(bit, 397 (unsigned long *)&recv_int_page[dword])) { 398 relid = (dword << 5) + bit; 399 400 if (relid == 0) 401 /* 402 * Special case - vmbus 403 * channel protocol msg 404 */ 405 continue; 406 407 process_chn_event(relid); 408 } 409 } 410 } 411} 412 413/* 414 * vmbus_post_msg - Send a msg on the vmbus's message connection 415 */ 416int vmbus_post_msg(void *buffer, size_t buflen) 417{ 418 union hv_connection_id conn_id; 419 int ret = 0; 420 int retries = 0; 421 422 conn_id.asu32 = 0; 423 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID; 424 425 /* 426 * hv_post_message() can have transient failures because of 427 * insufficient resources. Retry the operation a couple of 428 * times before giving up. 429 */ 430 while (retries < 10) { 431 ret = hv_post_message(conn_id, 1, buffer, buflen); 432 433 switch (ret) { 434 case HV_STATUS_INSUFFICIENT_BUFFERS: 435 ret = -ENOMEM; 436 case -ENOMEM: 437 break; 438 case HV_STATUS_SUCCESS: 439 return ret; 440 default: 441 pr_err("hv_post_msg() failed; error code:%d\n", ret); 442 return -EINVAL; 443 } 444 445 retries++; 446 msleep(100); 447 } 448 return ret; 449} 450 451/* 452 * vmbus_set_event - Send an event notification to the parent 453 */ 454int vmbus_set_event(struct vmbus_channel *channel) 455{ 456 u32 child_relid = channel->offermsg.child_relid; 457 458 if (!channel->is_dedicated_interrupt) { 459 /* Each u32 represents 32 channels */ 460 sync_set_bit(child_relid & 31, 461 (unsigned long *)vmbus_connection.send_int_page + 462 (child_relid >> 5)); 463 } 464 465 return hv_signal_event(channel->sig_event); 466} 467