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 EXPORT_SYMBOL_GPL(vmbus_connection); 43 44 /* 45 * Negotiated protocol version with the host. 46 */ 47 __u32 vmbus_proto_version; 48 EXPORT_SYMBOL_GPL(vmbus_proto_version); 49 50 static __u32 vmbus_get_next_version(__u32 current_version) 51 { 52 switch (current_version) { 53 case (VERSION_WIN7): 54 return VERSION_WS2008; 55 56 case (VERSION_WIN8): 57 return VERSION_WIN7; 58 59 case (VERSION_WIN8_1): 60 return VERSION_WIN8; 61 62 case (VERSION_WIN10): 63 return VERSION_WIN8_1; 64 65 case (VERSION_WS2008): 66 default: 67 return VERSION_INVAL; 68 } 69 } 70 71 static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, 72 __u32 version) 73 { 74 int ret = 0; 75 struct vmbus_channel_initiate_contact *msg; 76 unsigned long flags; 77 78 init_completion(&msginfo->waitevent); 79 80 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg; 81 82 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT; 83 msg->vmbus_version_requested = version; 84 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page); 85 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]); 86 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]); 87 /* 88 * We want all channel messages to be delivered on CPU 0. 89 * This has been the behavior pre-win8. This is not 90 * perf issue and having all channel messages delivered on CPU 0 91 * would be ok. 92 * For post win8 hosts, we support receiving channel messagges on 93 * all the CPUs. This is needed for kexec to work correctly where 94 * the CPU attempting to connect may not be CPU 0. 95 */ 96 if (version >= VERSION_WIN8_1) 97 msg->target_vcpu = hv_context.vp_index[smp_processor_id()]; 98 else 99 msg->target_vcpu = 0; 100 101 /* 102 * Add to list before we send the request since we may 103 * receive the response before returning from this routine 104 */ 105 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 106 list_add_tail(&msginfo->msglistentry, 107 &vmbus_connection.chn_msg_list); 108 109 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 110 111 ret = vmbus_post_msg(msg, 112 sizeof(struct vmbus_channel_initiate_contact), 113 true); 114 if (ret != 0) { 115 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 116 list_del(&msginfo->msglistentry); 117 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, 118 flags); 119 return ret; 120 } 121 122 /* Wait for the connection response */ 123 wait_for_completion(&msginfo->waitevent); 124 125 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 126 list_del(&msginfo->msglistentry); 127 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 128 129 /* Check if successful */ 130 if (msginfo->response.version_response.version_supported) { 131 vmbus_connection.conn_state = CONNECTED; 132 } else { 133 return -ECONNREFUSED; 134 } 135 136 return ret; 137 } 138 139 /* 140 * vmbus_connect - Sends a connect request on the partition service connection 141 */ 142 int vmbus_connect(void) 143 { 144 int ret = 0; 145 struct vmbus_channel_msginfo *msginfo = NULL; 146 __u32 version; 147 148 /* Initialize the vmbus connection */ 149 vmbus_connection.conn_state = CONNECTING; 150 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con"); 151 if (!vmbus_connection.work_queue) { 152 ret = -ENOMEM; 153 goto cleanup; 154 } 155 156 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list); 157 spin_lock_init(&vmbus_connection.channelmsg_lock); 158 159 INIT_LIST_HEAD(&vmbus_connection.chn_list); 160 mutex_init(&vmbus_connection.channel_mutex); 161 162 /* 163 * Setup the vmbus event connection for channel interrupt 164 * abstraction stuff 165 */ 166 vmbus_connection.int_page = 167 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0); 168 if (vmbus_connection.int_page == NULL) { 169 ret = -ENOMEM; 170 goto cleanup; 171 } 172 173 vmbus_connection.recv_int_page = vmbus_connection.int_page; 174 vmbus_connection.send_int_page = 175 (void *)((unsigned long)vmbus_connection.int_page + 176 (PAGE_SIZE >> 1)); 177 178 /* 179 * Setup the monitor notification facility. The 1st page for 180 * parent->child and the 2nd page for child->parent 181 */ 182 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 183 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 184 if ((vmbus_connection.monitor_pages[0] == NULL) || 185 (vmbus_connection.monitor_pages[1] == NULL)) { 186 ret = -ENOMEM; 187 goto cleanup; 188 } 189 190 msginfo = kzalloc(sizeof(*msginfo) + 191 sizeof(struct vmbus_channel_initiate_contact), 192 GFP_KERNEL); 193 if (msginfo == NULL) { 194 ret = -ENOMEM; 195 goto cleanup; 196 } 197 198 /* 199 * Negotiate a compatible VMBUS version number with the 200 * host. We start with the highest number we can support 201 * and work our way down until we negotiate a compatible 202 * version. 203 */ 204 205 version = VERSION_CURRENT; 206 207 do { 208 ret = vmbus_negotiate_version(msginfo, version); 209 if (ret == -ETIMEDOUT) 210 goto cleanup; 211 212 if (vmbus_connection.conn_state == CONNECTED) 213 break; 214 215 version = vmbus_get_next_version(version); 216 } while (version != VERSION_INVAL); 217 218 if (version == VERSION_INVAL) 219 goto cleanup; 220 221 vmbus_proto_version = version; 222 pr_info("Vmbus version:%d.%d\n", 223 version >> 16, version & 0xFFFF); 224 225 kfree(msginfo); 226 return 0; 227 228 cleanup: 229 pr_err("Unable to connect to host\n"); 230 231 vmbus_connection.conn_state = DISCONNECTED; 232 vmbus_disconnect(); 233 234 kfree(msginfo); 235 236 return ret; 237 } 238 239 void vmbus_disconnect(void) 240 { 241 /* 242 * First send the unload request to the host. 243 */ 244 vmbus_initiate_unload(false); 245 246 if (vmbus_connection.work_queue) { 247 drain_workqueue(vmbus_connection.work_queue); 248 destroy_workqueue(vmbus_connection.work_queue); 249 } 250 251 if (vmbus_connection.int_page) { 252 free_pages((unsigned long)vmbus_connection.int_page, 0); 253 vmbus_connection.int_page = NULL; 254 } 255 256 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0); 257 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0); 258 vmbus_connection.monitor_pages[0] = NULL; 259 vmbus_connection.monitor_pages[1] = NULL; 260 } 261 262 /* 263 * relid2channel - Get the channel object given its 264 * child relative id (ie channel id) 265 */ 266 struct vmbus_channel *relid2channel(u32 relid) 267 { 268 struct vmbus_channel *channel; 269 struct vmbus_channel *found_channel = NULL; 270 struct list_head *cur, *tmp; 271 struct vmbus_channel *cur_sc; 272 273 BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex)); 274 275 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { 276 if (channel->offermsg.child_relid == relid) { 277 found_channel = channel; 278 break; 279 } else if (!list_empty(&channel->sc_list)) { 280 /* 281 * Deal with sub-channels. 282 */ 283 list_for_each_safe(cur, tmp, &channel->sc_list) { 284 cur_sc = list_entry(cur, struct vmbus_channel, 285 sc_list); 286 if (cur_sc->offermsg.child_relid == relid) { 287 found_channel = cur_sc; 288 break; 289 } 290 } 291 } 292 } 293 294 return found_channel; 295 } 296 297 /* 298 * vmbus_on_event - Process a channel event notification 299 * 300 * For batched channels (default) optimize host to guest signaling 301 * by ensuring: 302 * 1. While reading the channel, we disable interrupts from host. 303 * 2. Ensure that we process all posted messages from the host 304 * before returning from this callback. 305 * 3. Once we return, enable signaling from the host. Once this 306 * state is set we check to see if additional packets are 307 * available to read. In this case we repeat the process. 308 * If this tasklet has been running for a long time 309 * then reschedule ourselves. 310 */ 311 void vmbus_on_event(unsigned long data) 312 { 313 struct vmbus_channel *channel = (void *) data; 314 unsigned long time_limit = jiffies + 2; 315 316 do { 317 void (*callback_fn)(void *); 318 319 /* A channel once created is persistent even when 320 * there is no driver handling the device. An 321 * unloading driver sets the onchannel_callback to NULL. 322 */ 323 callback_fn = READ_ONCE(channel->onchannel_callback); 324 if (unlikely(callback_fn == NULL)) 325 return; 326 327 (*callback_fn)(channel->channel_callback_context); 328 329 if (channel->callback_mode != HV_CALL_BATCHED) 330 return; 331 332 if (likely(hv_end_read(&channel->inbound) == 0)) 333 return; 334 335 hv_begin_read(&channel->inbound); 336 } while (likely(time_before(jiffies, time_limit))); 337 338 /* The time limit (2 jiffies) has been reached */ 339 tasklet_schedule(&channel->callback_event); 340 } 341 342 /* 343 * vmbus_post_msg - Send a msg on the vmbus's message connection 344 */ 345 int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep) 346 { 347 union hv_connection_id conn_id; 348 int ret = 0; 349 int retries = 0; 350 u32 usec = 1; 351 352 conn_id.asu32 = 0; 353 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID; 354 355 /* 356 * hv_post_message() can have transient failures because of 357 * insufficient resources. Retry the operation a couple of 358 * times before giving up. 359 */ 360 while (retries < 100) { 361 ret = hv_post_message(conn_id, 1, buffer, buflen); 362 363 switch (ret) { 364 case HV_STATUS_INVALID_CONNECTION_ID: 365 /* 366 * We could get this if we send messages too 367 * frequently. 368 */ 369 ret = -EAGAIN; 370 break; 371 case HV_STATUS_INSUFFICIENT_MEMORY: 372 case HV_STATUS_INSUFFICIENT_BUFFERS: 373 ret = -ENOMEM; 374 break; 375 case HV_STATUS_SUCCESS: 376 return ret; 377 default: 378 pr_err("hv_post_msg() failed; error code:%d\n", ret); 379 return -EINVAL; 380 } 381 382 retries++; 383 if (can_sleep && usec > 1000) 384 msleep(usec / 1000); 385 else if (usec < MAX_UDELAY_MS * 1000) 386 udelay(usec); 387 else 388 mdelay(usec / 1000); 389 390 if (usec < 256000) 391 usec *= 2; 392 } 393 return ret; 394 } 395 396 /* 397 * vmbus_set_event - Send an event notification to the parent 398 */ 399 void vmbus_set_event(struct vmbus_channel *channel) 400 { 401 u32 child_relid = channel->offermsg.child_relid; 402 403 if (!channel->is_dedicated_interrupt) 404 vmbus_send_interrupt(child_relid); 405 406 hv_do_hypercall(HVCALL_SIGNAL_EVENT, channel->sig_event, NULL); 407 } 408 EXPORT_SYMBOL_GPL(vmbus_set_event); 409