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