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_WS2008): 59 default: 60 return VERSION_INVAL; 61 } 62 } 63 64 static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, 65 __u32 version) 66 { 67 int ret = 0; 68 struct vmbus_channel_initiate_contact *msg; 69 unsigned long flags; 70 int t; 71 72 init_completion(&msginfo->waitevent); 73 74 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg; 75 76 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT; 77 msg->vmbus_version_requested = version; 78 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page); 79 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages); 80 msg->monitor_page2 = virt_to_phys( 81 (void *)((unsigned long)vmbus_connection.monitor_pages + 82 PAGE_SIZE)); 83 84 /* 85 * Add to list before we send the request since we may 86 * receive the response before returning from this routine 87 */ 88 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 89 list_add_tail(&msginfo->msglistentry, 90 &vmbus_connection.chn_msg_list); 91 92 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 93 94 ret = vmbus_post_msg(msg, 95 sizeof(struct vmbus_channel_initiate_contact)); 96 if (ret != 0) { 97 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 98 list_del(&msginfo->msglistentry); 99 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, 100 flags); 101 return ret; 102 } 103 104 /* Wait for the connection response */ 105 t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ); 106 if (t == 0) { 107 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, 108 flags); 109 list_del(&msginfo->msglistentry); 110 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, 111 flags); 112 return -ETIMEDOUT; 113 } 114 115 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 116 list_del(&msginfo->msglistentry); 117 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 118 119 /* Check if successful */ 120 if (msginfo->response.version_response.version_supported) { 121 vmbus_connection.conn_state = CONNECTED; 122 } else { 123 return -ECONNREFUSED; 124 } 125 126 return ret; 127 } 128 129 /* 130 * vmbus_connect - Sends a connect request on the partition service connection 131 */ 132 int vmbus_connect(void) 133 { 134 int ret = 0; 135 struct vmbus_channel_msginfo *msginfo = NULL; 136 __u32 version; 137 138 /* Initialize the vmbus connection */ 139 vmbus_connection.conn_state = CONNECTING; 140 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con"); 141 if (!vmbus_connection.work_queue) { 142 ret = -ENOMEM; 143 goto cleanup; 144 } 145 146 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list); 147 spin_lock_init(&vmbus_connection.channelmsg_lock); 148 149 INIT_LIST_HEAD(&vmbus_connection.chn_list); 150 spin_lock_init(&vmbus_connection.channel_lock); 151 152 /* 153 * Setup the vmbus event connection for channel interrupt 154 * abstraction stuff 155 */ 156 vmbus_connection.int_page = 157 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0); 158 if (vmbus_connection.int_page == NULL) { 159 ret = -ENOMEM; 160 goto cleanup; 161 } 162 163 vmbus_connection.recv_int_page = vmbus_connection.int_page; 164 vmbus_connection.send_int_page = 165 (void *)((unsigned long)vmbus_connection.int_page + 166 (PAGE_SIZE >> 1)); 167 168 /* 169 * Setup the monitor notification facility. The 1st page for 170 * parent->child and the 2nd page for child->parent 171 */ 172 vmbus_connection.monitor_pages = 173 (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 1); 174 if (vmbus_connection.monitor_pages == 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) 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 vmbus_connection.conn_state = DISCONNECTED; 223 224 if (vmbus_connection.work_queue) 225 destroy_workqueue(vmbus_connection.work_queue); 226 227 if (vmbus_connection.int_page) { 228 free_pages((unsigned long)vmbus_connection.int_page, 0); 229 vmbus_connection.int_page = NULL; 230 } 231 232 if (vmbus_connection.monitor_pages) { 233 free_pages((unsigned long)vmbus_connection.monitor_pages, 1); 234 vmbus_connection.monitor_pages = NULL; 235 } 236 237 kfree(msginfo); 238 239 return ret; 240 } 241 242 243 /* 244 * relid2channel - Get the channel object given its 245 * child relative id (ie channel id) 246 */ 247 struct vmbus_channel *relid2channel(u32 relid) 248 { 249 struct vmbus_channel *channel; 250 struct vmbus_channel *found_channel = NULL; 251 unsigned long flags; 252 struct list_head *cur, *tmp; 253 struct vmbus_channel *cur_sc; 254 255 spin_lock_irqsave(&vmbus_connection.channel_lock, flags); 256 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { 257 if (channel->offermsg.child_relid == relid) { 258 found_channel = channel; 259 break; 260 } else if (!list_empty(&channel->sc_list)) { 261 /* 262 * Deal with sub-channels. 263 */ 264 list_for_each_safe(cur, tmp, &channel->sc_list) { 265 cur_sc = list_entry(cur, struct vmbus_channel, 266 sc_list); 267 if (cur_sc->offermsg.child_relid == relid) { 268 found_channel = cur_sc; 269 break; 270 } 271 } 272 } 273 } 274 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags); 275 276 return found_channel; 277 } 278 279 /* 280 * process_chn_event - Process a channel event notification 281 */ 282 static void process_chn_event(u32 relid) 283 { 284 struct vmbus_channel *channel; 285 unsigned long flags; 286 void *arg; 287 bool read_state; 288 u32 bytes_to_read; 289 290 /* 291 * Find the channel based on this relid and invokes the 292 * channel callback to process the event 293 */ 294 channel = relid2channel(relid); 295 296 if (!channel) { 297 pr_err("channel not found for relid - %u\n", relid); 298 return; 299 } 300 301 /* 302 * A channel once created is persistent even when there 303 * is no driver handling the device. An unloading driver 304 * sets the onchannel_callback to NULL under the 305 * protection of the channel inbound_lock. Thus, checking 306 * and invoking the driver specific callback takes care of 307 * orderly unloading of the driver. 308 */ 309 310 spin_lock_irqsave(&channel->inbound_lock, flags); 311 if (channel->onchannel_callback != NULL) { 312 arg = channel->channel_callback_context; 313 read_state = channel->batched_reading; 314 /* 315 * This callback reads the messages sent by the host. 316 * We can optimize host to guest signaling by ensuring: 317 * 1. While reading the channel, we disable interrupts from 318 * host. 319 * 2. Ensure that we process all posted messages from the host 320 * before returning from this callback. 321 * 3. Once we return, enable signaling from the host. Once this 322 * state is set we check to see if additional packets are 323 * available to read. In this case we repeat the process. 324 */ 325 326 do { 327 hv_begin_read(&channel->inbound); 328 channel->onchannel_callback(arg); 329 bytes_to_read = hv_end_read(&channel->inbound); 330 } while (read_state && (bytes_to_read != 0)); 331 } else { 332 pr_err("no channel callback for relid - %u\n", relid); 333 } 334 335 spin_unlock_irqrestore(&channel->inbound_lock, flags); 336 } 337 338 /* 339 * vmbus_on_event - Handler for events 340 */ 341 void vmbus_on_event(unsigned long data) 342 { 343 u32 dword; 344 u32 maxdword; 345 int bit; 346 u32 relid; 347 u32 *recv_int_page = NULL; 348 void *page_addr; 349 int cpu = smp_processor_id(); 350 union hv_synic_event_flags *event; 351 352 if ((vmbus_proto_version == VERSION_WS2008) || 353 (vmbus_proto_version == VERSION_WIN7)) { 354 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5; 355 recv_int_page = vmbus_connection.recv_int_page; 356 } else { 357 /* 358 * When the host is win8 and beyond, the event page 359 * can be directly checked to get the id of the channel 360 * that has the interrupt pending. 361 */ 362 maxdword = HV_EVENT_FLAGS_DWORD_COUNT; 363 page_addr = hv_context.synic_event_page[cpu]; 364 event = (union hv_synic_event_flags *)page_addr + 365 VMBUS_MESSAGE_SINT; 366 recv_int_page = event->flags32; 367 } 368 369 370 371 /* Check events */ 372 if (!recv_int_page) 373 return; 374 for (dword = 0; dword < maxdword; dword++) { 375 if (!recv_int_page[dword]) 376 continue; 377 for (bit = 0; bit < 32; bit++) { 378 if (sync_test_and_clear_bit(bit, 379 (unsigned long *)&recv_int_page[dword])) { 380 relid = (dword << 5) + bit; 381 382 if (relid == 0) 383 /* 384 * Special case - vmbus 385 * channel protocol msg 386 */ 387 continue; 388 389 process_chn_event(relid); 390 } 391 } 392 } 393 } 394 395 /* 396 * vmbus_post_msg - Send a msg on the vmbus's message connection 397 */ 398 int vmbus_post_msg(void *buffer, size_t buflen) 399 { 400 union hv_connection_id conn_id; 401 int ret = 0; 402 int retries = 0; 403 404 conn_id.asu32 = 0; 405 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID; 406 407 /* 408 * hv_post_message() can have transient failures because of 409 * insufficient resources. Retry the operation a couple of 410 * times before giving up. 411 */ 412 while (retries < 3) { 413 ret = hv_post_message(conn_id, 1, buffer, buflen); 414 if (ret != HV_STATUS_INSUFFICIENT_BUFFERS) 415 return ret; 416 retries++; 417 msleep(100); 418 } 419 return ret; 420 } 421 422 /* 423 * vmbus_set_event - Send an event notification to the parent 424 */ 425 int vmbus_set_event(struct vmbus_channel *channel) 426 { 427 u32 child_relid = channel->offermsg.child_relid; 428 429 if (!channel->is_dedicated_interrupt) { 430 /* Each u32 represents 32 channels */ 431 sync_set_bit(child_relid & 31, 432 (unsigned long *)vmbus_connection.send_int_page + 433 (child_relid >> 5)); 434 } 435 436 return hv_signal_event(channel->sig_event); 437 } 438