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 vmbus_connection.conn_state = DISCONNECTED; 220 221 if (vmbus_connection.work_queue) 222 destroy_workqueue(vmbus_connection.work_queue); 223 224 if (vmbus_connection.int_page) { 225 free_pages((unsigned long)vmbus_connection.int_page, 0); 226 vmbus_connection.int_page = NULL; 227 } 228 229 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0); 230 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0); 231 vmbus_connection.monitor_pages[0] = NULL; 232 vmbus_connection.monitor_pages[1] = NULL; 233 234 kfree(msginfo); 235 236 return ret; 237 } 238 239 /* 240 * Map the given relid to the corresponding channel based on the 241 * per-cpu list of channels that have been affinitized to this CPU. 242 * This will be used in the channel callback path as we can do this 243 * mapping in a lock-free fashion. 244 */ 245 static struct vmbus_channel *pcpu_relid2channel(u32 relid) 246 { 247 struct vmbus_channel *channel; 248 struct vmbus_channel *found_channel = NULL; 249 int cpu = smp_processor_id(); 250 struct list_head *pcpu_head = &hv_context.percpu_list[cpu]; 251 252 list_for_each_entry(channel, pcpu_head, percpu_list) { 253 if (channel->offermsg.child_relid == relid) { 254 found_channel = channel; 255 break; 256 } 257 } 258 259 return found_channel; 260 } 261 262 /* 263 * relid2channel - Get the channel object given its 264 * child relative id (ie channel id) 265 */ 266 struct vmbus_channel *relid2channel(u32 relid) 267 { 268 struct vmbus_channel *channel; 269 struct vmbus_channel *found_channel = NULL; 270 unsigned long flags; 271 struct list_head *cur, *tmp; 272 struct vmbus_channel *cur_sc; 273 274 spin_lock_irqsave(&vmbus_connection.channel_lock, flags); 275 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { 276 if (channel->offermsg.child_relid == relid) { 277 found_channel = channel; 278 break; 279 } else if (!list_empty(&channel->sc_list)) { 280 /* 281 * Deal with sub-channels. 282 */ 283 list_for_each_safe(cur, tmp, &channel->sc_list) { 284 cur_sc = list_entry(cur, struct vmbus_channel, 285 sc_list); 286 if (cur_sc->offermsg.child_relid == relid) { 287 found_channel = cur_sc; 288 break; 289 } 290 } 291 } 292 } 293 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags); 294 295 return found_channel; 296 } 297 298 /* 299 * process_chn_event - Process a channel event notification 300 */ 301 static void process_chn_event(u32 relid) 302 { 303 struct vmbus_channel *channel; 304 void *arg; 305 bool read_state; 306 u32 bytes_to_read; 307 308 /* 309 * Find the channel based on this relid and invokes the 310 * channel callback to process the event 311 */ 312 channel = pcpu_relid2channel(relid); 313 314 if (!channel) { 315 pr_err("channel not found for relid - %u\n", relid); 316 return; 317 } 318 319 /* 320 * A channel once created is persistent even when there 321 * is no driver handling the device. An unloading driver 322 * sets the onchannel_callback to NULL on the same CPU 323 * as where this interrupt is handled (in an interrupt context). 324 * Thus, checking and invoking the driver specific callback takes 325 * care of orderly unloading of the driver. 326 */ 327 328 if (channel->onchannel_callback != NULL) { 329 arg = channel->channel_callback_context; 330 read_state = channel->batched_reading; 331 /* 332 * This callback reads the messages sent by the host. 333 * We can optimize host to guest signaling by ensuring: 334 * 1. While reading the channel, we disable interrupts from 335 * host. 336 * 2. Ensure that we process all posted messages from the host 337 * before returning from this callback. 338 * 3. Once we return, enable signaling from the host. Once this 339 * state is set we check to see if additional packets are 340 * available to read. In this case we repeat the process. 341 */ 342 343 do { 344 if (read_state) 345 hv_begin_read(&channel->inbound); 346 channel->onchannel_callback(arg); 347 if (read_state) 348 bytes_to_read = hv_end_read(&channel->inbound); 349 else 350 bytes_to_read = 0; 351 } while (read_state && (bytes_to_read != 0)); 352 } else { 353 pr_err("no channel callback for relid - %u\n", relid); 354 } 355 356 } 357 358 /* 359 * vmbus_on_event - Handler for events 360 */ 361 void vmbus_on_event(unsigned long data) 362 { 363 u32 dword; 364 u32 maxdword; 365 int bit; 366 u32 relid; 367 u32 *recv_int_page = NULL; 368 void *page_addr; 369 int cpu = smp_processor_id(); 370 union hv_synic_event_flags *event; 371 372 if ((vmbus_proto_version == VERSION_WS2008) || 373 (vmbus_proto_version == VERSION_WIN7)) { 374 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5; 375 recv_int_page = vmbus_connection.recv_int_page; 376 } else { 377 /* 378 * When the host is win8 and beyond, the event page 379 * can be directly checked to get the id of the channel 380 * that has the interrupt pending. 381 */ 382 maxdword = HV_EVENT_FLAGS_DWORD_COUNT; 383 page_addr = hv_context.synic_event_page[cpu]; 384 event = (union hv_synic_event_flags *)page_addr + 385 VMBUS_MESSAGE_SINT; 386 recv_int_page = event->flags32; 387 } 388 389 390 391 /* Check events */ 392 if (!recv_int_page) 393 return; 394 for (dword = 0; dword < maxdword; dword++) { 395 if (!recv_int_page[dword]) 396 continue; 397 for (bit = 0; bit < 32; bit++) { 398 if (sync_test_and_clear_bit(bit, 399 (unsigned long *)&recv_int_page[dword])) { 400 relid = (dword << 5) + bit; 401 402 if (relid == 0) 403 /* 404 * Special case - vmbus 405 * channel protocol msg 406 */ 407 continue; 408 409 process_chn_event(relid); 410 } 411 } 412 } 413 } 414 415 /* 416 * vmbus_post_msg - Send a msg on the vmbus's message connection 417 */ 418 int vmbus_post_msg(void *buffer, size_t buflen) 419 { 420 union hv_connection_id conn_id; 421 int ret = 0; 422 int retries = 0; 423 424 conn_id.asu32 = 0; 425 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID; 426 427 /* 428 * hv_post_message() can have transient failures because of 429 * insufficient resources. Retry the operation a couple of 430 * times before giving up. 431 */ 432 while (retries < 10) { 433 ret = hv_post_message(conn_id, 1, buffer, buflen); 434 435 switch (ret) { 436 case HV_STATUS_INSUFFICIENT_BUFFERS: 437 ret = -ENOMEM; 438 case -ENOMEM: 439 break; 440 case HV_STATUS_SUCCESS: 441 return ret; 442 default: 443 pr_err("hv_post_msg() failed; error code:%d\n", ret); 444 return -EINVAL; 445 } 446 447 retries++; 448 msleep(100); 449 } 450 return ret; 451 } 452 453 /* 454 * vmbus_set_event - Send an event notification to the parent 455 */ 456 int vmbus_set_event(struct vmbus_channel *channel) 457 { 458 u32 child_relid = channel->offermsg.child_relid; 459 460 if (!channel->is_dedicated_interrupt) { 461 /* Each u32 represents 32 channels */ 462 sync_set_bit(child_relid & 31, 463 (unsigned long *)vmbus_connection.send_int_page + 464 (child_relid >> 5)); 465 } 466 467 return hv_signal_event(channel->sig_event); 468 } 469