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 71 init_completion(&msginfo->waitevent); 72 73 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg; 74 75 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT; 76 msg->vmbus_version_requested = version; 77 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page); 78 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]); 79 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]); 80 if (version == VERSION_WIN8) 81 msg->target_vcpu = hv_context.vp_index[smp_processor_id()]; 82 83 /* 84 * Add to list before we send the request since we may 85 * receive the response before returning from this routine 86 */ 87 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 88 list_add_tail(&msginfo->msglistentry, 89 &vmbus_connection.chn_msg_list); 90 91 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 92 93 ret = vmbus_post_msg(msg, 94 sizeof(struct vmbus_channel_initiate_contact)); 95 if (ret != 0) { 96 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 97 list_del(&msginfo->msglistentry); 98 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, 99 flags); 100 return ret; 101 } 102 103 /* Wait for the connection response */ 104 wait_for_completion(&msginfo->waitevent); 105 106 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 107 list_del(&msginfo->msglistentry); 108 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 109 110 /* Check if successful */ 111 if (msginfo->response.version_response.version_supported) { 112 vmbus_connection.conn_state = CONNECTED; 113 } else { 114 return -ECONNREFUSED; 115 } 116 117 return ret; 118 } 119 120 /* 121 * vmbus_connect - Sends a connect request on the partition service connection 122 */ 123 int vmbus_connect(void) 124 { 125 int ret = 0; 126 struct vmbus_channel_msginfo *msginfo = NULL; 127 __u32 version; 128 129 /* Initialize the vmbus connection */ 130 vmbus_connection.conn_state = CONNECTING; 131 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con"); 132 if (!vmbus_connection.work_queue) { 133 ret = -ENOMEM; 134 goto cleanup; 135 } 136 137 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list); 138 spin_lock_init(&vmbus_connection.channelmsg_lock); 139 140 INIT_LIST_HEAD(&vmbus_connection.chn_list); 141 spin_lock_init(&vmbus_connection.channel_lock); 142 143 /* 144 * Setup the vmbus event connection for channel interrupt 145 * abstraction stuff 146 */ 147 vmbus_connection.int_page = 148 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0); 149 if (vmbus_connection.int_page == NULL) { 150 ret = -ENOMEM; 151 goto cleanup; 152 } 153 154 vmbus_connection.recv_int_page = vmbus_connection.int_page; 155 vmbus_connection.send_int_page = 156 (void *)((unsigned long)vmbus_connection.int_page + 157 (PAGE_SIZE >> 1)); 158 159 /* 160 * Setup the monitor notification facility. The 1st page for 161 * parent->child and the 2nd page for child->parent 162 */ 163 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 164 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 165 if ((vmbus_connection.monitor_pages[0] == NULL) || 166 (vmbus_connection.monitor_pages[1] == NULL)) { 167 ret = -ENOMEM; 168 goto cleanup; 169 } 170 171 msginfo = kzalloc(sizeof(*msginfo) + 172 sizeof(struct vmbus_channel_initiate_contact), 173 GFP_KERNEL); 174 if (msginfo == NULL) { 175 ret = -ENOMEM; 176 goto cleanup; 177 } 178 179 /* 180 * Negotiate a compatible VMBUS version number with the 181 * host. We start with the highest number we can support 182 * and work our way down until we negotiate a compatible 183 * version. 184 */ 185 186 version = VERSION_CURRENT; 187 188 do { 189 ret = vmbus_negotiate_version(msginfo, version); 190 if (ret == -ETIMEDOUT) 191 goto cleanup; 192 193 if (vmbus_connection.conn_state == CONNECTED) 194 break; 195 196 version = vmbus_get_next_version(version); 197 } while (version != VERSION_INVAL); 198 199 if (version == VERSION_INVAL) 200 goto cleanup; 201 202 vmbus_proto_version = version; 203 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d; Vmbus version:%d.%d\n", 204 host_info_eax, host_info_ebx >> 16, 205 host_info_ebx & 0xFFFF, host_info_ecx, 206 host_info_edx >> 24, host_info_edx & 0xFFFFFF, 207 version >> 16, version & 0xFFFF); 208 209 kfree(msginfo); 210 return 0; 211 212 cleanup: 213 pr_err("Unable to connect to host\n"); 214 vmbus_connection.conn_state = DISCONNECTED; 215 216 if (vmbus_connection.work_queue) 217 destroy_workqueue(vmbus_connection.work_queue); 218 219 if (vmbus_connection.int_page) { 220 free_pages((unsigned long)vmbus_connection.int_page, 0); 221 vmbus_connection.int_page = NULL; 222 } 223 224 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 1); 225 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 1); 226 vmbus_connection.monitor_pages[0] = NULL; 227 vmbus_connection.monitor_pages[1] = NULL; 228 229 kfree(msginfo); 230 231 return ret; 232 } 233 234 235 /* 236 * relid2channel - Get the channel object given its 237 * child relative id (ie channel id) 238 */ 239 struct vmbus_channel *relid2channel(u32 relid) 240 { 241 struct vmbus_channel *channel; 242 struct vmbus_channel *found_channel = NULL; 243 unsigned long flags; 244 struct list_head *cur, *tmp; 245 struct vmbus_channel *cur_sc; 246 247 spin_lock_irqsave(&vmbus_connection.channel_lock, flags); 248 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { 249 if (channel->offermsg.child_relid == relid) { 250 found_channel = channel; 251 break; 252 } else if (!list_empty(&channel->sc_list)) { 253 /* 254 * Deal with sub-channels. 255 */ 256 list_for_each_safe(cur, tmp, &channel->sc_list) { 257 cur_sc = list_entry(cur, struct vmbus_channel, 258 sc_list); 259 if (cur_sc->offermsg.child_relid == relid) { 260 found_channel = cur_sc; 261 break; 262 } 263 } 264 } 265 } 266 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags); 267 268 return found_channel; 269 } 270 271 /* 272 * process_chn_event - Process a channel event notification 273 */ 274 static void process_chn_event(u32 relid) 275 { 276 struct vmbus_channel *channel; 277 unsigned long flags; 278 void *arg; 279 bool read_state; 280 u32 bytes_to_read; 281 282 /* 283 * Find the channel based on this relid and invokes the 284 * channel callback to process the event 285 */ 286 channel = relid2channel(relid); 287 288 if (!channel) { 289 pr_err("channel not found for relid - %u\n", relid); 290 return; 291 } 292 293 /* 294 * A channel once created is persistent even when there 295 * is no driver handling the device. An unloading driver 296 * sets the onchannel_callback to NULL under the 297 * protection of the channel inbound_lock. Thus, checking 298 * and invoking the driver specific callback takes care of 299 * orderly unloading of the driver. 300 */ 301 302 spin_lock_irqsave(&channel->inbound_lock, flags); 303 if (channel->onchannel_callback != NULL) { 304 arg = channel->channel_callback_context; 305 read_state = channel->batched_reading; 306 /* 307 * This callback reads the messages sent by the host. 308 * We can optimize host to guest signaling by ensuring: 309 * 1. While reading the channel, we disable interrupts from 310 * host. 311 * 2. Ensure that we process all posted messages from the host 312 * before returning from this callback. 313 * 3. Once we return, enable signaling from the host. Once this 314 * state is set we check to see if additional packets are 315 * available to read. In this case we repeat the process. 316 */ 317 318 do { 319 hv_begin_read(&channel->inbound); 320 channel->onchannel_callback(arg); 321 bytes_to_read = hv_end_read(&channel->inbound); 322 } while (read_state && (bytes_to_read != 0)); 323 } else { 324 pr_err("no channel callback for relid - %u\n", relid); 325 } 326 327 spin_unlock_irqrestore(&channel->inbound_lock, flags); 328 } 329 330 /* 331 * vmbus_on_event - Handler for events 332 */ 333 void vmbus_on_event(unsigned long data) 334 { 335 u32 dword; 336 u32 maxdword; 337 int bit; 338 u32 relid; 339 u32 *recv_int_page = NULL; 340 void *page_addr; 341 int cpu = smp_processor_id(); 342 union hv_synic_event_flags *event; 343 344 if ((vmbus_proto_version == VERSION_WS2008) || 345 (vmbus_proto_version == VERSION_WIN7)) { 346 maxdword = MAX_NUM_CHANNELS_SUPPORTED >> 5; 347 recv_int_page = vmbus_connection.recv_int_page; 348 } else { 349 /* 350 * When the host is win8 and beyond, the event page 351 * can be directly checked to get the id of the channel 352 * that has the interrupt pending. 353 */ 354 maxdword = HV_EVENT_FLAGS_DWORD_COUNT; 355 page_addr = hv_context.synic_event_page[cpu]; 356 event = (union hv_synic_event_flags *)page_addr + 357 VMBUS_MESSAGE_SINT; 358 recv_int_page = event->flags32; 359 } 360 361 362 363 /* Check events */ 364 if (!recv_int_page) 365 return; 366 for (dword = 0; dword < maxdword; dword++) { 367 if (!recv_int_page[dword]) 368 continue; 369 for (bit = 0; bit < 32; bit++) { 370 if (sync_test_and_clear_bit(bit, 371 (unsigned long *)&recv_int_page[dword])) { 372 relid = (dword << 5) + bit; 373 374 if (relid == 0) 375 /* 376 * Special case - vmbus 377 * channel protocol msg 378 */ 379 continue; 380 381 process_chn_event(relid); 382 } 383 } 384 } 385 } 386 387 /* 388 * vmbus_post_msg - Send a msg on the vmbus's message connection 389 */ 390 int vmbus_post_msg(void *buffer, size_t buflen) 391 { 392 union hv_connection_id conn_id; 393 int ret = 0; 394 int retries = 0; 395 396 conn_id.asu32 = 0; 397 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID; 398 399 /* 400 * hv_post_message() can have transient failures because of 401 * insufficient resources. Retry the operation a couple of 402 * times before giving up. 403 */ 404 while (retries < 3) { 405 ret = hv_post_message(conn_id, 1, buffer, buflen); 406 if (ret != HV_STATUS_INSUFFICIENT_BUFFERS) 407 return ret; 408 retries++; 409 msleep(100); 410 } 411 return ret; 412 } 413 414 /* 415 * vmbus_set_event - Send an event notification to the parent 416 */ 417 int vmbus_set_event(struct vmbus_channel *channel) 418 { 419 u32 child_relid = channel->offermsg.child_relid; 420 421 if (!channel->is_dedicated_interrupt) { 422 /* Each u32 represents 32 channels */ 423 sync_set_bit(child_relid & 31, 424 (unsigned long *)vmbus_connection.send_int_page + 425 (child_relid >> 5)); 426 } 427 428 return hv_signal_event(channel->sig_event); 429 } 430