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_WS2008): 62 default: 63 return VERSION_INVAL; 64 } 65 } 66 67 static 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[get_cpu()]; 85 put_cpu(); 86 } 87 88 /* 89 * Add to list before we send the request since we may 90 * receive the response before returning from this routine 91 */ 92 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 93 list_add_tail(&msginfo->msglistentry, 94 &vmbus_connection.chn_msg_list); 95 96 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 97 98 ret = vmbus_post_msg(msg, 99 sizeof(struct vmbus_channel_initiate_contact)); 100 if (ret != 0) { 101 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 102 list_del(&msginfo->msglistentry); 103 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, 104 flags); 105 return ret; 106 } 107 108 /* Wait for the connection response */ 109 wait_for_completion(&msginfo->waitevent); 110 111 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 112 list_del(&msginfo->msglistentry); 113 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 114 115 /* Check if successful */ 116 if (msginfo->response.version_response.version_supported) { 117 vmbus_connection.conn_state = CONNECTED; 118 } else { 119 return -ECONNREFUSED; 120 } 121 122 return ret; 123 } 124 125 /* 126 * vmbus_connect - Sends a connect request on the partition service connection 127 */ 128 int vmbus_connect(void) 129 { 130 int ret = 0; 131 struct vmbus_channel_msginfo *msginfo = NULL; 132 __u32 version; 133 134 /* Initialize the vmbus connection */ 135 vmbus_connection.conn_state = CONNECTING; 136 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con"); 137 if (!vmbus_connection.work_queue) { 138 ret = -ENOMEM; 139 goto cleanup; 140 } 141 142 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list); 143 spin_lock_init(&vmbus_connection.channelmsg_lock); 144 145 INIT_LIST_HEAD(&vmbus_connection.chn_list); 146 spin_lock_init(&vmbus_connection.channel_lock); 147 148 /* 149 * Setup the vmbus event connection for channel interrupt 150 * abstraction stuff 151 */ 152 vmbus_connection.int_page = 153 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0); 154 if (vmbus_connection.int_page == NULL) { 155 ret = -ENOMEM; 156 goto cleanup; 157 } 158 159 vmbus_connection.recv_int_page = vmbus_connection.int_page; 160 vmbus_connection.send_int_page = 161 (void *)((unsigned long)vmbus_connection.int_page + 162 (PAGE_SIZE >> 1)); 163 164 /* 165 * Setup the monitor notification facility. The 1st page for 166 * parent->child and the 2nd page for child->parent 167 */ 168 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 169 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 170 if ((vmbus_connection.monitor_pages[0] == NULL) || 171 (vmbus_connection.monitor_pages[1] == NULL)) { 172 ret = -ENOMEM; 173 goto cleanup; 174 } 175 176 msginfo = kzalloc(sizeof(*msginfo) + 177 sizeof(struct vmbus_channel_initiate_contact), 178 GFP_KERNEL); 179 if (msginfo == NULL) { 180 ret = -ENOMEM; 181 goto cleanup; 182 } 183 184 /* 185 * Negotiate a compatible VMBUS version number with the 186 * host. We start with the highest number we can support 187 * and work our way down until we negotiate a compatible 188 * version. 189 */ 190 191 version = VERSION_CURRENT; 192 193 do { 194 ret = vmbus_negotiate_version(msginfo, version); 195 if (ret == -ETIMEDOUT) 196 goto cleanup; 197 198 if (vmbus_connection.conn_state == CONNECTED) 199 break; 200 201 version = vmbus_get_next_version(version); 202 } while (version != VERSION_INVAL); 203 204 if (version == VERSION_INVAL) 205 goto cleanup; 206 207 vmbus_proto_version = version; 208 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d; Vmbus version:%d.%d\n", 209 host_info_eax, host_info_ebx >> 16, 210 host_info_ebx & 0xFFFF, host_info_ecx, 211 host_info_edx >> 24, host_info_edx & 0xFFFFFF, 212 version >> 16, version & 0xFFFF); 213 214 kfree(msginfo); 215 return 0; 216 217 cleanup: 218 pr_err("Unable to connect to host\n"); 219 220 vmbus_connection.conn_state = DISCONNECTED; 221 vmbus_disconnect(); 222 223 kfree(msginfo); 224 225 return ret; 226 } 227 228 void vmbus_disconnect(void) 229 { 230 if (vmbus_connection.work_queue) { 231 drain_workqueue(vmbus_connection.work_queue); 232 destroy_workqueue(vmbus_connection.work_queue); 233 } 234 235 if (vmbus_connection.int_page) { 236 free_pages((unsigned long)vmbus_connection.int_page, 0); 237 vmbus_connection.int_page = NULL; 238 } 239 240 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0); 241 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0); 242 vmbus_connection.monitor_pages[0] = NULL; 243 vmbus_connection.monitor_pages[1] = NULL; 244 } 245 246 /* 247 * Map the given relid to the corresponding channel based on the 248 * per-cpu list of channels that have been affinitized to this CPU. 249 * This will be used in the channel callback path as we can do this 250 * mapping in a lock-free fashion. 251 */ 252 static struct vmbus_channel *pcpu_relid2channel(u32 relid) 253 { 254 struct vmbus_channel *channel; 255 struct vmbus_channel *found_channel = NULL; 256 int cpu = smp_processor_id(); 257 struct list_head *pcpu_head = &hv_context.percpu_list[cpu]; 258 259 list_for_each_entry(channel, pcpu_head, percpu_list) { 260 if (channel->offermsg.child_relid == relid) { 261 found_channel = channel; 262 break; 263 } 264 } 265 266 return found_channel; 267 } 268 269 /* 270 * relid2channel - Get the channel object given its 271 * child relative id (ie channel id) 272 */ 273 struct vmbus_channel *relid2channel(u32 relid) 274 { 275 struct vmbus_channel *channel; 276 struct vmbus_channel *found_channel = NULL; 277 unsigned long flags; 278 struct list_head *cur, *tmp; 279 struct vmbus_channel *cur_sc; 280 281 spin_lock_irqsave(&vmbus_connection.channel_lock, flags); 282 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { 283 if (channel->offermsg.child_relid == relid) { 284 found_channel = channel; 285 break; 286 } else if (!list_empty(&channel->sc_list)) { 287 /* 288 * Deal with sub-channels. 289 */ 290 list_for_each_safe(cur, tmp, &channel->sc_list) { 291 cur_sc = list_entry(cur, struct vmbus_channel, 292 sc_list); 293 if (cur_sc->offermsg.child_relid == relid) { 294 found_channel = cur_sc; 295 break; 296 } 297 } 298 } 299 } 300 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags); 301 302 return found_channel; 303 } 304 305 /* 306 * process_chn_event - Process a channel event notification 307 */ 308 static void process_chn_event(u32 relid) 309 { 310 struct vmbus_channel *channel; 311 void *arg; 312 bool read_state; 313 u32 bytes_to_read; 314 315 /* 316 * Find the channel based on this relid and invokes the 317 * channel callback to process the event 318 */ 319 channel = pcpu_relid2channel(relid); 320 321 if (!channel) 322 return; 323 324 /* 325 * A channel once created is persistent even when there 326 * is no driver handling the device. An unloading driver 327 * sets the onchannel_callback to NULL on the same CPU 328 * as where this interrupt is handled (in an interrupt context). 329 * Thus, checking and invoking the driver specific callback takes 330 * care of orderly unloading of the driver. 331 */ 332 333 if (channel->onchannel_callback != NULL) { 334 arg = channel->channel_callback_context; 335 read_state = channel->batched_reading; 336 /* 337 * This callback reads the messages sent by the host. 338 * We can optimize host to guest signaling by ensuring: 339 * 1. While reading the channel, we disable interrupts from 340 * host. 341 * 2. Ensure that we process all posted messages from the host 342 * before returning from this callback. 343 * 3. Once we return, enable signaling from the host. Once this 344 * state is set we check to see if additional packets are 345 * available to read. In this case we repeat the process. 346 */ 347 348 do { 349 if (read_state) 350 hv_begin_read(&channel->inbound); 351 channel->onchannel_callback(arg); 352 if (read_state) 353 bytes_to_read = hv_end_read(&channel->inbound); 354 else 355 bytes_to_read = 0; 356 } while (read_state && (bytes_to_read != 0)); 357 } 358 } 359 360 /* 361 * vmbus_on_event - Handler for events 362 */ 363 void vmbus_on_event(unsigned long data) 364 { 365 u32 dword; 366 u32 maxdword; 367 int bit; 368 u32 relid; 369 u32 *recv_int_page = NULL; 370 void *page_addr; 371 int cpu = smp_processor_id(); 372 union hv_synic_event_flags *event; 373 374 if ((vmbus_proto_version == VERSION_WS2008) || 375 (vmbus_proto_version == VERSION_WIN7)) { 376 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5; 377 recv_int_page = vmbus_connection.recv_int_page; 378 } else { 379 /* 380 * When the host is win8 and beyond, the event page 381 * can be directly checked to get the id of the channel 382 * that has the interrupt pending. 383 */ 384 maxdword = HV_EVENT_FLAGS_DWORD_COUNT; 385 page_addr = hv_context.synic_event_page[cpu]; 386 event = (union hv_synic_event_flags *)page_addr + 387 VMBUS_MESSAGE_SINT; 388 recv_int_page = event->flags32; 389 } 390 391 392 393 /* Check events */ 394 if (!recv_int_page) 395 return; 396 for (dword = 0; dword < maxdword; dword++) { 397 if (!recv_int_page[dword]) 398 continue; 399 for (bit = 0; bit < 32; bit++) { 400 if (sync_test_and_clear_bit(bit, 401 (unsigned long *)&recv_int_page[dword])) { 402 relid = (dword << 5) + bit; 403 404 if (relid == 0) 405 /* 406 * Special case - vmbus 407 * channel protocol msg 408 */ 409 continue; 410 411 process_chn_event(relid); 412 } 413 } 414 } 415 } 416 417 /* 418 * vmbus_post_msg - Send a msg on the vmbus's message connection 419 */ 420 int vmbus_post_msg(void *buffer, size_t buflen) 421 { 422 union hv_connection_id conn_id; 423 int ret = 0; 424 int retries = 0; 425 u32 msec = 1; 426 427 conn_id.asu32 = 0; 428 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID; 429 430 /* 431 * hv_post_message() can have transient failures because of 432 * insufficient resources. Retry the operation a couple of 433 * times before giving up. 434 */ 435 while (retries < 20) { 436 ret = hv_post_message(conn_id, 1, buffer, buflen); 437 438 switch (ret) { 439 case HV_STATUS_INVALID_CONNECTION_ID: 440 /* 441 * We could get this if we send messages too 442 * frequently. 443 */ 444 ret = -EAGAIN; 445 break; 446 case HV_STATUS_INSUFFICIENT_MEMORY: 447 case HV_STATUS_INSUFFICIENT_BUFFERS: 448 ret = -ENOMEM; 449 break; 450 case HV_STATUS_SUCCESS: 451 return ret; 452 default: 453 pr_err("hv_post_msg() failed; error code:%d\n", ret); 454 return -EINVAL; 455 } 456 457 retries++; 458 msleep(msec); 459 if (msec < 2048) 460 msec *= 2; 461 } 462 return ret; 463 } 464 465 /* 466 * vmbus_set_event - Send an event notification to the parent 467 */ 468 int vmbus_set_event(struct vmbus_channel *channel) 469 { 470 u32 child_relid = channel->offermsg.child_relid; 471 472 if (!channel->is_dedicated_interrupt) { 473 /* Each u32 represents 32 channels */ 474 sync_set_bit(child_relid & 31, 475 (unsigned long *)vmbus_connection.send_int_page + 476 (child_relid >> 5)); 477 } 478 479 return hv_signal_event(channel->sig_event); 480 } 481