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 == 0) 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 if (vmbus_connection.monitor_pages) { 230 free_pages((unsigned long)vmbus_connection.monitor_pages, 1); 231 vmbus_connection.monitor_pages = NULL; 232 } 233 234 kfree(msginfo); 235 236 return ret; 237 } 238 239 240 /* 241 * relid2channel - Get the channel object given its 242 * child relative id (ie channel id) 243 */ 244 struct vmbus_channel *relid2channel(u32 relid) 245 { 246 struct vmbus_channel *channel; 247 struct vmbus_channel *found_channel = NULL; 248 unsigned long flags; 249 250 spin_lock_irqsave(&vmbus_connection.channel_lock, flags); 251 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { 252 if (channel->offermsg.child_relid == relid) { 253 found_channel = channel; 254 break; 255 } 256 } 257 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags); 258 259 return found_channel; 260 } 261 262 /* 263 * process_chn_event - Process a channel event notification 264 */ 265 static void process_chn_event(u32 relid) 266 { 267 struct vmbus_channel *channel; 268 unsigned long flags; 269 void *arg; 270 bool read_state; 271 u32 bytes_to_read; 272 273 /* 274 * Find the channel based on this relid and invokes the 275 * channel callback to process the event 276 */ 277 channel = relid2channel(relid); 278 279 if (!channel) { 280 pr_err("channel not found for relid - %u\n", relid); 281 return; 282 } 283 284 /* 285 * A channel once created is persistent even when there 286 * is no driver handling the device. An unloading driver 287 * sets the onchannel_callback to NULL under the 288 * protection of the channel inbound_lock. Thus, checking 289 * and invoking the driver specific callback takes care of 290 * orderly unloading of the driver. 291 */ 292 293 spin_lock_irqsave(&channel->inbound_lock, flags); 294 if (channel->onchannel_callback != NULL) { 295 arg = channel->channel_callback_context; 296 read_state = channel->batched_reading; 297 /* 298 * This callback reads the messages sent by the host. 299 * We can optimize host to guest signaling by ensuring: 300 * 1. While reading the channel, we disable interrupts from 301 * host. 302 * 2. Ensure that we process all posted messages from the host 303 * before returning from this callback. 304 * 3. Once we return, enable signaling from the host. Once this 305 * state is set we check to see if additional packets are 306 * available to read. In this case we repeat the process. 307 */ 308 309 do { 310 hv_begin_read(&channel->inbound); 311 channel->onchannel_callback(arg); 312 bytes_to_read = hv_end_read(&channel->inbound); 313 } while (read_state && (bytes_to_read != 0)); 314 } else { 315 pr_err("no channel callback for relid - %u\n", relid); 316 } 317 318 spin_unlock_irqrestore(&channel->inbound_lock, flags); 319 } 320 321 /* 322 * vmbus_on_event - Handler for events 323 */ 324 void vmbus_on_event(unsigned long data) 325 { 326 u32 dword; 327 u32 maxdword; 328 int bit; 329 u32 relid; 330 u32 *recv_int_page = NULL; 331 void *page_addr; 332 int cpu = smp_processor_id(); 333 union hv_synic_event_flags *event; 334 335 if ((vmbus_proto_version == VERSION_WS2008) || 336 (vmbus_proto_version == VERSION_WIN7)) { 337 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5; 338 recv_int_page = vmbus_connection.recv_int_page; 339 } else { 340 /* 341 * When the host is win8 and beyond, the event page 342 * can be directly checked to get the id of the channel 343 * that has the interrupt pending. 344 */ 345 maxdword = HV_EVENT_FLAGS_DWORD_COUNT; 346 page_addr = hv_context.synic_event_page[cpu]; 347 event = (union hv_synic_event_flags *)page_addr + 348 VMBUS_MESSAGE_SINT; 349 recv_int_page = event->flags32; 350 } 351 352 353 354 /* Check events */ 355 if (!recv_int_page) 356 return; 357 for (dword = 0; dword < maxdword; dword++) { 358 if (!recv_int_page[dword]) 359 continue; 360 for (bit = 0; bit < 32; bit++) { 361 if (sync_test_and_clear_bit(bit, 362 (unsigned long *)&recv_int_page[dword])) { 363 relid = (dword << 5) + bit; 364 365 if (relid == 0) 366 /* 367 * Special case - vmbus 368 * channel protocol msg 369 */ 370 continue; 371 372 process_chn_event(relid); 373 } 374 } 375 } 376 } 377 378 /* 379 * vmbus_post_msg - Send a msg on the vmbus's message connection 380 */ 381 int vmbus_post_msg(void *buffer, size_t buflen) 382 { 383 union hv_connection_id conn_id; 384 int ret = 0; 385 int retries = 0; 386 387 conn_id.asu32 = 0; 388 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID; 389 390 /* 391 * hv_post_message() can have transient failures because of 392 * insufficient resources. Retry the operation a couple of 393 * times before giving up. 394 */ 395 while (retries < 3) { 396 ret = hv_post_message(conn_id, 1, buffer, buflen); 397 if (ret != HV_STATUS_INSUFFICIENT_BUFFERS) 398 return ret; 399 retries++; 400 msleep(100); 401 } 402 return ret; 403 } 404 405 /* 406 * vmbus_set_event - Send an event notification to the parent 407 */ 408 int vmbus_set_event(struct vmbus_channel *channel) 409 { 410 u32 child_relid = channel->offermsg.child_relid; 411 412 if (!channel->is_dedicated_interrupt) { 413 /* Each u32 represents 32 channels */ 414 sync_set_bit(child_relid & 31, 415 (unsigned long *)vmbus_connection.send_int_page + 416 (child_relid >> 5)); 417 } 418 419 return hv_signal_event(channel->sig_event); 420 } 421