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