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 vmbus_connection.connect_cpu = smp_processor_id(); 99 } else { 100 msg->target_vcpu = 0; 101 vmbus_connection.connect_cpu = 0; 102 } 103 104 /* 105 * Add to list before we send the request since we may 106 * receive the response before returning from this routine 107 */ 108 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 109 list_add_tail(&msginfo->msglistentry, 110 &vmbus_connection.chn_msg_list); 111 112 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 113 114 ret = vmbus_post_msg(msg, 115 sizeof(struct vmbus_channel_initiate_contact), 116 true); 117 if (ret != 0) { 118 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 119 list_del(&msginfo->msglistentry); 120 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, 121 flags); 122 return ret; 123 } 124 125 /* Wait for the connection response */ 126 wait_for_completion(&msginfo->waitevent); 127 128 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 129 list_del(&msginfo->msglistentry); 130 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 131 132 /* Check if successful */ 133 if (msginfo->response.version_response.version_supported) { 134 vmbus_connection.conn_state = CONNECTED; 135 } else { 136 return -ECONNREFUSED; 137 } 138 139 return ret; 140 } 141 142 /* 143 * vmbus_connect - Sends a connect request on the partition service connection 144 */ 145 int vmbus_connect(void) 146 { 147 int ret = 0; 148 struct vmbus_channel_msginfo *msginfo = NULL; 149 __u32 version; 150 151 /* Initialize the vmbus connection */ 152 vmbus_connection.conn_state = CONNECTING; 153 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con"); 154 if (!vmbus_connection.work_queue) { 155 ret = -ENOMEM; 156 goto cleanup; 157 } 158 159 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list); 160 spin_lock_init(&vmbus_connection.channelmsg_lock); 161 162 INIT_LIST_HEAD(&vmbus_connection.chn_list); 163 mutex_init(&vmbus_connection.channel_mutex); 164 165 /* 166 * Setup the vmbus event connection for channel interrupt 167 * abstraction stuff 168 */ 169 vmbus_connection.int_page = 170 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0); 171 if (vmbus_connection.int_page == NULL) { 172 ret = -ENOMEM; 173 goto cleanup; 174 } 175 176 vmbus_connection.recv_int_page = vmbus_connection.int_page; 177 vmbus_connection.send_int_page = 178 (void *)((unsigned long)vmbus_connection.int_page + 179 (PAGE_SIZE >> 1)); 180 181 /* 182 * Setup the monitor notification facility. The 1st page for 183 * parent->child and the 2nd page for child->parent 184 */ 185 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 186 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 187 if ((vmbus_connection.monitor_pages[0] == NULL) || 188 (vmbus_connection.monitor_pages[1] == NULL)) { 189 ret = -ENOMEM; 190 goto cleanup; 191 } 192 193 msginfo = kzalloc(sizeof(*msginfo) + 194 sizeof(struct vmbus_channel_initiate_contact), 195 GFP_KERNEL); 196 if (msginfo == NULL) { 197 ret = -ENOMEM; 198 goto cleanup; 199 } 200 201 /* 202 * Negotiate a compatible VMBUS version number with the 203 * host. We start with the highest number we can support 204 * and work our way down until we negotiate a compatible 205 * version. 206 */ 207 208 version = VERSION_CURRENT; 209 210 do { 211 ret = vmbus_negotiate_version(msginfo, version); 212 if (ret == -ETIMEDOUT) 213 goto cleanup; 214 215 if (vmbus_connection.conn_state == CONNECTED) 216 break; 217 218 version = vmbus_get_next_version(version); 219 } while (version != VERSION_INVAL); 220 221 if (version == VERSION_INVAL) 222 goto cleanup; 223 224 vmbus_proto_version = version; 225 pr_info("Vmbus version:%d.%d\n", 226 version >> 16, version & 0xFFFF); 227 228 kfree(msginfo); 229 return 0; 230 231 cleanup: 232 pr_err("Unable to connect to host\n"); 233 234 vmbus_connection.conn_state = DISCONNECTED; 235 vmbus_disconnect(); 236 237 kfree(msginfo); 238 239 return ret; 240 } 241 242 void vmbus_disconnect(void) 243 { 244 /* 245 * First send the unload request to the host. 246 */ 247 vmbus_initiate_unload(false); 248 249 if (vmbus_connection.work_queue) { 250 drain_workqueue(vmbus_connection.work_queue); 251 destroy_workqueue(vmbus_connection.work_queue); 252 } 253 254 if (vmbus_connection.int_page) { 255 free_pages((unsigned long)vmbus_connection.int_page, 0); 256 vmbus_connection.int_page = NULL; 257 } 258 259 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0); 260 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0); 261 vmbus_connection.monitor_pages[0] = NULL; 262 vmbus_connection.monitor_pages[1] = NULL; 263 } 264 265 /* 266 * relid2channel - Get the channel object given its 267 * child relative id (ie channel id) 268 */ 269 struct vmbus_channel *relid2channel(u32 relid) 270 { 271 struct vmbus_channel *channel; 272 struct vmbus_channel *found_channel = NULL; 273 struct list_head *cur, *tmp; 274 struct vmbus_channel *cur_sc; 275 276 BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex)); 277 278 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { 279 if (channel->offermsg.child_relid == relid) { 280 found_channel = channel; 281 break; 282 } else if (!list_empty(&channel->sc_list)) { 283 /* 284 * Deal with sub-channels. 285 */ 286 list_for_each_safe(cur, tmp, &channel->sc_list) { 287 cur_sc = list_entry(cur, struct vmbus_channel, 288 sc_list); 289 if (cur_sc->offermsg.child_relid == relid) { 290 found_channel = cur_sc; 291 break; 292 } 293 } 294 } 295 } 296 297 return found_channel; 298 } 299 300 /* 301 * vmbus_on_event - Process a channel event notification 302 * 303 * For batched channels (default) optimize host to guest signaling 304 * by ensuring: 305 * 1. While reading the channel, we disable interrupts from host. 306 * 2. Ensure that we process all posted messages from the host 307 * before returning from this callback. 308 * 3. Once we return, enable signaling from the host. Once this 309 * state is set we check to see if additional packets are 310 * available to read. In this case we repeat the process. 311 * If this tasklet has been running for a long time 312 * then reschedule ourselves. 313 */ 314 void vmbus_on_event(unsigned long data) 315 { 316 struct vmbus_channel *channel = (void *) data; 317 unsigned long time_limit = jiffies + 2; 318 319 do { 320 void (*callback_fn)(void *); 321 322 /* A channel once created is persistent even when 323 * there is no driver handling the device. An 324 * unloading driver sets the onchannel_callback to NULL. 325 */ 326 callback_fn = READ_ONCE(channel->onchannel_callback); 327 if (unlikely(callback_fn == NULL)) 328 return; 329 330 (*callback_fn)(channel->channel_callback_context); 331 332 if (channel->callback_mode != HV_CALL_BATCHED) 333 return; 334 335 if (likely(hv_end_read(&channel->inbound) == 0)) 336 return; 337 338 hv_begin_read(&channel->inbound); 339 } while (likely(time_before(jiffies, time_limit))); 340 341 /* The time limit (2 jiffies) has been reached */ 342 tasklet_schedule(&channel->callback_event); 343 } 344 345 /* 346 * vmbus_post_msg - Send a msg on the vmbus's message connection 347 */ 348 int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep) 349 { 350 union hv_connection_id conn_id; 351 int ret = 0; 352 int retries = 0; 353 u32 usec = 1; 354 355 conn_id.asu32 = 0; 356 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID; 357 358 /* 359 * hv_post_message() can have transient failures because of 360 * insufficient resources. Retry the operation a couple of 361 * times before giving up. 362 */ 363 while (retries < 100) { 364 ret = hv_post_message(conn_id, 1, buffer, buflen); 365 366 switch (ret) { 367 case HV_STATUS_INVALID_CONNECTION_ID: 368 /* 369 * We could get this if we send messages too 370 * frequently. 371 */ 372 ret = -EAGAIN; 373 break; 374 case HV_STATUS_INSUFFICIENT_MEMORY: 375 case HV_STATUS_INSUFFICIENT_BUFFERS: 376 ret = -ENOBUFS; 377 break; 378 case HV_STATUS_SUCCESS: 379 return ret; 380 default: 381 pr_err("hv_post_msg() failed; error code:%d\n", ret); 382 return -EINVAL; 383 } 384 385 retries++; 386 if (can_sleep && usec > 1000) 387 msleep(usec / 1000); 388 else if (usec < MAX_UDELAY_MS * 1000) 389 udelay(usec); 390 else 391 mdelay(usec / 1000); 392 393 if (retries < 22) 394 usec *= 2; 395 } 396 return ret; 397 } 398 399 /* 400 * vmbus_set_event - Send an event notification to the parent 401 */ 402 void vmbus_set_event(struct vmbus_channel *channel) 403 { 404 u32 child_relid = channel->offermsg.child_relid; 405 406 if (!channel->is_dedicated_interrupt) 407 vmbus_send_interrupt(child_relid); 408 409 hv_do_hypercall(HVCALL_SIGNAL_EVENT, channel->sig_event, NULL); 410 } 411 EXPORT_SYMBOL_GPL(vmbus_set_event); 412