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 <asm/mshyperv.h> 36 37 #include "hyperv_vmbus.h" 38 39 40 struct vmbus_connection vmbus_connection = { 41 .conn_state = DISCONNECTED, 42 .next_gpadl_handle = ATOMIC_INIT(0xE1E10), 43 }; 44 EXPORT_SYMBOL_GPL(vmbus_connection); 45 46 /* 47 * Negotiated protocol version with the host. 48 */ 49 __u32 vmbus_proto_version; 50 EXPORT_SYMBOL_GPL(vmbus_proto_version); 51 52 static __u32 vmbus_get_next_version(__u32 current_version) 53 { 54 switch (current_version) { 55 case (VERSION_WIN7): 56 return VERSION_WS2008; 57 58 case (VERSION_WIN8): 59 return VERSION_WIN7; 60 61 case (VERSION_WIN8_1): 62 return VERSION_WIN8; 63 64 case (VERSION_WIN10): 65 return VERSION_WIN8_1; 66 67 case (VERSION_WS2008): 68 default: 69 return VERSION_INVAL; 70 } 71 } 72 73 static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, 74 __u32 version) 75 { 76 int ret = 0; 77 struct vmbus_channel_initiate_contact *msg; 78 unsigned long flags; 79 80 init_completion(&msginfo->waitevent); 81 82 msg = (struct vmbus_channel_initiate_contact *)msginfo->msg; 83 84 msg->header.msgtype = CHANNELMSG_INITIATE_CONTACT; 85 msg->vmbus_version_requested = version; 86 msg->interrupt_page = virt_to_phys(vmbus_connection.int_page); 87 msg->monitor_page1 = virt_to_phys(vmbus_connection.monitor_pages[0]); 88 msg->monitor_page2 = virt_to_phys(vmbus_connection.monitor_pages[1]); 89 /* 90 * We want all channel messages to be delivered on CPU 0. 91 * This has been the behavior pre-win8. This is not 92 * perf issue and having all channel messages delivered on CPU 0 93 * would be ok. 94 * For post win8 hosts, we support receiving channel messagges on 95 * all the CPUs. This is needed for kexec to work correctly where 96 * the CPU attempting to connect may not be CPU 0. 97 */ 98 if (version >= VERSION_WIN8_1) { 99 msg->target_vcpu = 100 hv_cpu_number_to_vp_number(smp_processor_id()); 101 vmbus_connection.connect_cpu = smp_processor_id(); 102 } else { 103 msg->target_vcpu = 0; 104 vmbus_connection.connect_cpu = 0; 105 } 106 107 /* 108 * Add to list before we send the request since we may 109 * receive the response before returning from this routine 110 */ 111 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 112 list_add_tail(&msginfo->msglistentry, 113 &vmbus_connection.chn_msg_list); 114 115 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 116 117 ret = vmbus_post_msg(msg, 118 sizeof(struct vmbus_channel_initiate_contact), 119 true); 120 if (ret != 0) { 121 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 122 list_del(&msginfo->msglistentry); 123 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, 124 flags); 125 return ret; 126 } 127 128 /* Wait for the connection response */ 129 wait_for_completion(&msginfo->waitevent); 130 131 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags); 132 list_del(&msginfo->msglistentry); 133 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); 134 135 /* Check if successful */ 136 if (msginfo->response.version_response.version_supported) { 137 vmbus_connection.conn_state = CONNECTED; 138 } else { 139 return -ECONNREFUSED; 140 } 141 142 return ret; 143 } 144 145 /* 146 * vmbus_connect - Sends a connect request on the partition service connection 147 */ 148 int vmbus_connect(void) 149 { 150 int ret = 0; 151 struct vmbus_channel_msginfo *msginfo = NULL; 152 __u32 version; 153 154 /* Initialize the vmbus connection */ 155 vmbus_connection.conn_state = CONNECTING; 156 vmbus_connection.work_queue = create_workqueue("hv_vmbus_con"); 157 if (!vmbus_connection.work_queue) { 158 ret = -ENOMEM; 159 goto cleanup; 160 } 161 162 INIT_LIST_HEAD(&vmbus_connection.chn_msg_list); 163 spin_lock_init(&vmbus_connection.channelmsg_lock); 164 165 INIT_LIST_HEAD(&vmbus_connection.chn_list); 166 mutex_init(&vmbus_connection.channel_mutex); 167 168 /* 169 * Setup the vmbus event connection for channel interrupt 170 * abstraction stuff 171 */ 172 vmbus_connection.int_page = 173 (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, 0); 174 if (vmbus_connection.int_page == NULL) { 175 ret = -ENOMEM; 176 goto cleanup; 177 } 178 179 vmbus_connection.recv_int_page = vmbus_connection.int_page; 180 vmbus_connection.send_int_page = 181 (void *)((unsigned long)vmbus_connection.int_page + 182 (PAGE_SIZE >> 1)); 183 184 /* 185 * Setup the monitor notification facility. The 1st page for 186 * parent->child and the 2nd page for child->parent 187 */ 188 vmbus_connection.monitor_pages[0] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 189 vmbus_connection.monitor_pages[1] = (void *)__get_free_pages((GFP_KERNEL|__GFP_ZERO), 0); 190 if ((vmbus_connection.monitor_pages[0] == NULL) || 191 (vmbus_connection.monitor_pages[1] == NULL)) { 192 ret = -ENOMEM; 193 goto cleanup; 194 } 195 196 msginfo = kzalloc(sizeof(*msginfo) + 197 sizeof(struct vmbus_channel_initiate_contact), 198 GFP_KERNEL); 199 if (msginfo == NULL) { 200 ret = -ENOMEM; 201 goto cleanup; 202 } 203 204 /* 205 * Negotiate a compatible VMBUS version number with the 206 * host. We start with the highest number we can support 207 * and work our way down until we negotiate a compatible 208 * version. 209 */ 210 211 version = VERSION_CURRENT; 212 213 do { 214 ret = vmbus_negotiate_version(msginfo, version); 215 if (ret == -ETIMEDOUT) 216 goto cleanup; 217 218 if (vmbus_connection.conn_state == CONNECTED) 219 break; 220 221 version = vmbus_get_next_version(version); 222 } while (version != VERSION_INVAL); 223 224 if (version == VERSION_INVAL) 225 goto cleanup; 226 227 vmbus_proto_version = version; 228 pr_info("Vmbus version:%d.%d\n", 229 version >> 16, version & 0xFFFF); 230 231 kfree(msginfo); 232 return 0; 233 234 cleanup: 235 pr_err("Unable to connect to host\n"); 236 237 vmbus_connection.conn_state = DISCONNECTED; 238 vmbus_disconnect(); 239 240 kfree(msginfo); 241 242 return ret; 243 } 244 245 void vmbus_disconnect(void) 246 { 247 /* 248 * First send the unload request to the host. 249 */ 250 vmbus_initiate_unload(false); 251 252 if (vmbus_connection.work_queue) { 253 drain_workqueue(vmbus_connection.work_queue); 254 destroy_workqueue(vmbus_connection.work_queue); 255 } 256 257 if (vmbus_connection.int_page) { 258 free_pages((unsigned long)vmbus_connection.int_page, 0); 259 vmbus_connection.int_page = NULL; 260 } 261 262 free_pages((unsigned long)vmbus_connection.monitor_pages[0], 0); 263 free_pages((unsigned long)vmbus_connection.monitor_pages[1], 0); 264 vmbus_connection.monitor_pages[0] = NULL; 265 vmbus_connection.monitor_pages[1] = NULL; 266 } 267 268 /* 269 * relid2channel - Get the channel object given its 270 * child relative id (ie channel id) 271 */ 272 struct vmbus_channel *relid2channel(u32 relid) 273 { 274 struct vmbus_channel *channel; 275 struct vmbus_channel *found_channel = NULL; 276 struct list_head *cur, *tmp; 277 struct vmbus_channel *cur_sc; 278 279 BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex)); 280 281 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { 282 if (channel->offermsg.child_relid == relid) { 283 found_channel = channel; 284 break; 285 } else if (!list_empty(&channel->sc_list)) { 286 /* 287 * Deal with sub-channels. 288 */ 289 list_for_each_safe(cur, tmp, &channel->sc_list) { 290 cur_sc = list_entry(cur, struct vmbus_channel, 291 sc_list); 292 if (cur_sc->offermsg.child_relid == relid) { 293 found_channel = cur_sc; 294 break; 295 } 296 } 297 } 298 } 299 300 return found_channel; 301 } 302 303 /* 304 * vmbus_on_event - Process a channel event notification 305 * 306 * For batched channels (default) optimize host to guest signaling 307 * by ensuring: 308 * 1. While reading the channel, we disable interrupts from host. 309 * 2. Ensure that we process all posted messages from the host 310 * before returning from this callback. 311 * 3. Once we return, enable signaling from the host. Once this 312 * state is set we check to see if additional packets are 313 * available to read. In this case we repeat the process. 314 * If this tasklet has been running for a long time 315 * then reschedule ourselves. 316 */ 317 void vmbus_on_event(unsigned long data) 318 { 319 struct vmbus_channel *channel = (void *) data; 320 unsigned long time_limit = jiffies + 2; 321 322 do { 323 void (*callback_fn)(void *); 324 325 /* A channel once created is persistent even when 326 * there is no driver handling the device. An 327 * unloading driver sets the onchannel_callback to NULL. 328 */ 329 callback_fn = READ_ONCE(channel->onchannel_callback); 330 if (unlikely(callback_fn == NULL)) 331 return; 332 333 (*callback_fn)(channel->channel_callback_context); 334 335 if (channel->callback_mode != HV_CALL_BATCHED) 336 return; 337 338 if (likely(hv_end_read(&channel->inbound) == 0)) 339 return; 340 341 hv_begin_read(&channel->inbound); 342 } while (likely(time_before(jiffies, time_limit))); 343 344 /* The time limit (2 jiffies) has been reached */ 345 tasklet_schedule(&channel->callback_event); 346 } 347 348 /* 349 * vmbus_post_msg - Send a msg on the vmbus's message connection 350 */ 351 int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep) 352 { 353 union hv_connection_id conn_id; 354 int ret = 0; 355 int retries = 0; 356 u32 usec = 1; 357 358 conn_id.asu32 = 0; 359 conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID; 360 361 /* 362 * hv_post_message() can have transient failures because of 363 * insufficient resources. Retry the operation a couple of 364 * times before giving up. 365 */ 366 while (retries < 100) { 367 ret = hv_post_message(conn_id, 1, buffer, buflen); 368 369 switch (ret) { 370 case HV_STATUS_INVALID_CONNECTION_ID: 371 /* 372 * We could get this if we send messages too 373 * frequently. 374 */ 375 ret = -EAGAIN; 376 break; 377 case HV_STATUS_INSUFFICIENT_MEMORY: 378 case HV_STATUS_INSUFFICIENT_BUFFERS: 379 ret = -ENOBUFS; 380 break; 381 case HV_STATUS_SUCCESS: 382 return ret; 383 default: 384 pr_err("hv_post_msg() failed; error code:%d\n", ret); 385 return -EINVAL; 386 } 387 388 retries++; 389 if (can_sleep && usec > 1000) 390 msleep(usec / 1000); 391 else if (usec < MAX_UDELAY_MS * 1000) 392 udelay(usec); 393 else 394 mdelay(usec / 1000); 395 396 if (retries < 22) 397 usec *= 2; 398 } 399 return ret; 400 } 401 402 /* 403 * vmbus_set_event - Send an event notification to the parent 404 */ 405 void vmbus_set_event(struct vmbus_channel *channel) 406 { 407 u32 child_relid = channel->offermsg.child_relid; 408 409 if (!channel->is_dedicated_interrupt) 410 vmbus_send_interrupt(child_relid); 411 412 hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event); 413 } 414 EXPORT_SYMBOL_GPL(vmbus_set_event); 415