1 /* 2 * Copyright (c) 2009, Microsoft Corporation. 3 * 4 * This program is free software; you can redistribute it and/or modify it 5 * under the terms and conditions of the GNU General Public License, 6 * version 2, as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 11 * more details. 12 * 13 * You should have received a copy of the GNU General Public License along with 14 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple 15 * Place - Suite 330, Boston, MA 02111-1307 USA. 16 * 17 * Authors: 18 * Haiyang Zhang <haiyangz@microsoft.com> 19 * Hank Janssen <hjanssen@microsoft.com> 20 * 21 */ 22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 23 24 #include <linux/kernel.h> 25 #include <linux/mm.h> 26 #include <linux/slab.h> 27 #include <linux/vmalloc.h> 28 #include <linux/hyperv.h> 29 #include <linux/version.h> 30 #include <linux/random.h> 31 #include <linux/clockchips.h> 32 #include <asm/mshyperv.h> 33 #include "hyperv_vmbus.h" 34 35 /* The one and only */ 36 struct hv_context hv_context = { 37 .synic_initialized = false, 38 }; 39 40 /* 41 * If false, we're using the old mechanism for stimer0 interrupts 42 * where it sends a VMbus message when it expires. The old 43 * mechanism is used when running on older versions of Hyper-V 44 * that don't support Direct Mode. While Hyper-V provides 45 * four stimer's per CPU, Linux uses only stimer0. 46 */ 47 static bool direct_mode_enabled; 48 static int stimer0_irq; 49 static int stimer0_vector; 50 51 #define HV_TIMER_FREQUENCY (10 * 1000 * 1000) /* 100ns period */ 52 #define HV_MAX_MAX_DELTA_TICKS 0xffffffff 53 #define HV_MIN_DELTA_TICKS 1 54 55 /* 56 * hv_init - Main initialization routine. 57 * 58 * This routine must be called before any other routines in here are called 59 */ 60 int hv_init(void) 61 { 62 hv_context.cpu_context = alloc_percpu(struct hv_per_cpu_context); 63 if (!hv_context.cpu_context) 64 return -ENOMEM; 65 66 direct_mode_enabled = ms_hyperv.misc_features & 67 HV_STIMER_DIRECT_MODE_AVAILABLE; 68 return 0; 69 } 70 71 /* 72 * hv_post_message - Post a message using the hypervisor message IPC. 73 * 74 * This involves a hypercall. 75 */ 76 int hv_post_message(union hv_connection_id connection_id, 77 enum hv_message_type message_type, 78 void *payload, size_t payload_size) 79 { 80 struct hv_input_post_message *aligned_msg; 81 struct hv_per_cpu_context *hv_cpu; 82 u64 status; 83 84 if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) 85 return -EMSGSIZE; 86 87 hv_cpu = get_cpu_ptr(hv_context.cpu_context); 88 aligned_msg = hv_cpu->post_msg_page; 89 aligned_msg->connectionid = connection_id; 90 aligned_msg->reserved = 0; 91 aligned_msg->message_type = message_type; 92 aligned_msg->payload_size = payload_size; 93 memcpy((void *)aligned_msg->payload, payload, payload_size); 94 95 status = hv_do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL); 96 97 /* Preemption must remain disabled until after the hypercall 98 * so some other thread can't get scheduled onto this cpu and 99 * corrupt the per-cpu post_msg_page 100 */ 101 put_cpu_ptr(hv_cpu); 102 103 return status & 0xFFFF; 104 } 105 106 /* 107 * ISR for when stimer0 is operating in Direct Mode. Direct Mode 108 * does not use VMbus or any VMbus messages, so process here and not 109 * in the VMbus driver code. 110 */ 111 112 static void hv_stimer0_isr(void) 113 { 114 struct hv_per_cpu_context *hv_cpu; 115 116 hv_cpu = this_cpu_ptr(hv_context.cpu_context); 117 hv_cpu->clk_evt->event_handler(hv_cpu->clk_evt); 118 add_interrupt_randomness(stimer0_vector, 0); 119 } 120 121 static int hv_ce_set_next_event(unsigned long delta, 122 struct clock_event_device *evt) 123 { 124 u64 current_tick; 125 126 WARN_ON(!clockevent_state_oneshot(evt)); 127 128 current_tick = hyperv_cs->read(NULL); 129 current_tick += delta; 130 hv_init_timer(0, current_tick); 131 return 0; 132 } 133 134 static int hv_ce_shutdown(struct clock_event_device *evt) 135 { 136 hv_init_timer(0, 0); 137 hv_init_timer_config(0, 0); 138 if (direct_mode_enabled) 139 hv_disable_stimer0_percpu_irq(stimer0_irq); 140 141 return 0; 142 } 143 144 static int hv_ce_set_oneshot(struct clock_event_device *evt) 145 { 146 union hv_timer_config timer_cfg; 147 148 timer_cfg.as_uint64 = 0; 149 timer_cfg.enable = 1; 150 timer_cfg.auto_enable = 1; 151 if (direct_mode_enabled) { 152 /* 153 * When it expires, the timer will directly interrupt 154 * on the specified hardware vector/IRQ. 155 */ 156 timer_cfg.direct_mode = 1; 157 timer_cfg.apic_vector = stimer0_vector; 158 hv_enable_stimer0_percpu_irq(stimer0_irq); 159 } else { 160 /* 161 * When it expires, the timer will generate a VMbus message, 162 * to be handled by the normal VMbus interrupt handler. 163 */ 164 timer_cfg.direct_mode = 0; 165 timer_cfg.sintx = VMBUS_MESSAGE_SINT; 166 } 167 hv_init_timer_config(0, timer_cfg.as_uint64); 168 return 0; 169 } 170 171 static void hv_init_clockevent_device(struct clock_event_device *dev, int cpu) 172 { 173 dev->name = "Hyper-V clockevent"; 174 dev->features = CLOCK_EVT_FEAT_ONESHOT; 175 dev->cpumask = cpumask_of(cpu); 176 dev->rating = 1000; 177 /* 178 * Avoid settint dev->owner = THIS_MODULE deliberately as doing so will 179 * result in clockevents_config_and_register() taking additional 180 * references to the hv_vmbus module making it impossible to unload. 181 */ 182 183 dev->set_state_shutdown = hv_ce_shutdown; 184 dev->set_state_oneshot = hv_ce_set_oneshot; 185 dev->set_next_event = hv_ce_set_next_event; 186 } 187 188 189 int hv_synic_alloc(void) 190 { 191 int cpu; 192 193 hv_context.hv_numa_map = kcalloc(nr_node_ids, sizeof(struct cpumask), 194 GFP_KERNEL); 195 if (hv_context.hv_numa_map == NULL) { 196 pr_err("Unable to allocate NUMA map\n"); 197 goto err; 198 } 199 200 for_each_present_cpu(cpu) { 201 struct hv_per_cpu_context *hv_cpu 202 = per_cpu_ptr(hv_context.cpu_context, cpu); 203 204 memset(hv_cpu, 0, sizeof(*hv_cpu)); 205 tasklet_init(&hv_cpu->msg_dpc, 206 vmbus_on_msg_dpc, (unsigned long) hv_cpu); 207 208 hv_cpu->clk_evt = kzalloc(sizeof(struct clock_event_device), 209 GFP_KERNEL); 210 if (hv_cpu->clk_evt == NULL) { 211 pr_err("Unable to allocate clock event device\n"); 212 goto err; 213 } 214 hv_init_clockevent_device(hv_cpu->clk_evt, cpu); 215 216 hv_cpu->synic_message_page = 217 (void *)get_zeroed_page(GFP_ATOMIC); 218 if (hv_cpu->synic_message_page == NULL) { 219 pr_err("Unable to allocate SYNIC message page\n"); 220 goto err; 221 } 222 223 hv_cpu->synic_event_page = (void *)get_zeroed_page(GFP_ATOMIC); 224 if (hv_cpu->synic_event_page == NULL) { 225 pr_err("Unable to allocate SYNIC event page\n"); 226 goto err; 227 } 228 229 hv_cpu->post_msg_page = (void *)get_zeroed_page(GFP_ATOMIC); 230 if (hv_cpu->post_msg_page == NULL) { 231 pr_err("Unable to allocate post msg page\n"); 232 goto err; 233 } 234 235 INIT_LIST_HEAD(&hv_cpu->chan_list); 236 } 237 238 if (direct_mode_enabled && 239 hv_setup_stimer0_irq(&stimer0_irq, &stimer0_vector, 240 hv_stimer0_isr)) 241 goto err; 242 243 return 0; 244 err: 245 /* 246 * Any memory allocations that succeeded will be freed when 247 * the caller cleans up by calling hv_synic_free() 248 */ 249 return -ENOMEM; 250 } 251 252 253 void hv_synic_free(void) 254 { 255 int cpu; 256 257 for_each_present_cpu(cpu) { 258 struct hv_per_cpu_context *hv_cpu 259 = per_cpu_ptr(hv_context.cpu_context, cpu); 260 261 kfree(hv_cpu->clk_evt); 262 free_page((unsigned long)hv_cpu->synic_event_page); 263 free_page((unsigned long)hv_cpu->synic_message_page); 264 free_page((unsigned long)hv_cpu->post_msg_page); 265 } 266 267 kfree(hv_context.hv_numa_map); 268 } 269 270 /* 271 * hv_synic_init - Initialize the Synthetic Interrupt Controller. 272 * 273 * If it is already initialized by another entity (ie x2v shim), we need to 274 * retrieve the initialized message and event pages. Otherwise, we create and 275 * initialize the message and event pages. 276 */ 277 int hv_synic_init(unsigned int cpu) 278 { 279 struct hv_per_cpu_context *hv_cpu 280 = per_cpu_ptr(hv_context.cpu_context, cpu); 281 union hv_synic_simp simp; 282 union hv_synic_siefp siefp; 283 union hv_synic_sint shared_sint; 284 union hv_synic_scontrol sctrl; 285 286 /* Setup the Synic's message page */ 287 hv_get_simp(simp.as_uint64); 288 simp.simp_enabled = 1; 289 simp.base_simp_gpa = virt_to_phys(hv_cpu->synic_message_page) 290 >> PAGE_SHIFT; 291 292 hv_set_simp(simp.as_uint64); 293 294 /* Setup the Synic's event page */ 295 hv_get_siefp(siefp.as_uint64); 296 siefp.siefp_enabled = 1; 297 siefp.base_siefp_gpa = virt_to_phys(hv_cpu->synic_event_page) 298 >> PAGE_SHIFT; 299 300 hv_set_siefp(siefp.as_uint64); 301 302 /* Setup the shared SINT. */ 303 hv_get_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64); 304 305 shared_sint.vector = HYPERVISOR_CALLBACK_VECTOR; 306 shared_sint.masked = false; 307 if (ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED) 308 shared_sint.auto_eoi = false; 309 else 310 shared_sint.auto_eoi = true; 311 312 hv_set_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64); 313 314 /* Enable the global synic bit */ 315 hv_get_synic_state(sctrl.as_uint64); 316 sctrl.enable = 1; 317 318 hv_set_synic_state(sctrl.as_uint64); 319 320 hv_context.synic_initialized = true; 321 322 /* 323 * Register the per-cpu clockevent source. 324 */ 325 if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE) 326 clockevents_config_and_register(hv_cpu->clk_evt, 327 HV_TIMER_FREQUENCY, 328 HV_MIN_DELTA_TICKS, 329 HV_MAX_MAX_DELTA_TICKS); 330 return 0; 331 } 332 333 /* 334 * hv_synic_clockevents_cleanup - Cleanup clockevent devices 335 */ 336 void hv_synic_clockevents_cleanup(void) 337 { 338 int cpu; 339 340 if (!(ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE)) 341 return; 342 343 if (direct_mode_enabled) 344 hv_remove_stimer0_irq(stimer0_irq); 345 346 for_each_present_cpu(cpu) { 347 struct hv_per_cpu_context *hv_cpu 348 = per_cpu_ptr(hv_context.cpu_context, cpu); 349 350 clockevents_unbind_device(hv_cpu->clk_evt, cpu); 351 } 352 } 353 354 /* 355 * hv_synic_cleanup - Cleanup routine for hv_synic_init(). 356 */ 357 int hv_synic_cleanup(unsigned int cpu) 358 { 359 union hv_synic_sint shared_sint; 360 union hv_synic_simp simp; 361 union hv_synic_siefp siefp; 362 union hv_synic_scontrol sctrl; 363 struct vmbus_channel *channel, *sc; 364 bool channel_found = false; 365 unsigned long flags; 366 367 if (!hv_context.synic_initialized) 368 return -EFAULT; 369 370 /* 371 * Search for channels which are bound to the CPU we're about to 372 * cleanup. In case we find one and vmbus is still connected we need to 373 * fail, this will effectively prevent CPU offlining. There is no way 374 * we can re-bind channels to different CPUs for now. 375 */ 376 mutex_lock(&vmbus_connection.channel_mutex); 377 list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { 378 if (channel->target_cpu == cpu) { 379 channel_found = true; 380 break; 381 } 382 spin_lock_irqsave(&channel->lock, flags); 383 list_for_each_entry(sc, &channel->sc_list, sc_list) { 384 if (sc->target_cpu == cpu) { 385 channel_found = true; 386 break; 387 } 388 } 389 spin_unlock_irqrestore(&channel->lock, flags); 390 if (channel_found) 391 break; 392 } 393 mutex_unlock(&vmbus_connection.channel_mutex); 394 395 if (channel_found && vmbus_connection.conn_state == CONNECTED) 396 return -EBUSY; 397 398 /* Turn off clockevent device */ 399 if (ms_hyperv.features & HV_MSR_SYNTIMER_AVAILABLE) { 400 struct hv_per_cpu_context *hv_cpu 401 = this_cpu_ptr(hv_context.cpu_context); 402 403 clockevents_unbind_device(hv_cpu->clk_evt, cpu); 404 hv_ce_shutdown(hv_cpu->clk_evt); 405 put_cpu_ptr(hv_cpu); 406 } 407 408 hv_get_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64); 409 410 shared_sint.masked = 1; 411 412 /* Need to correctly cleanup in the case of SMP!!! */ 413 /* Disable the interrupt */ 414 hv_set_synint_state(VMBUS_MESSAGE_SINT, shared_sint.as_uint64); 415 416 hv_get_simp(simp.as_uint64); 417 simp.simp_enabled = 0; 418 simp.base_simp_gpa = 0; 419 420 hv_set_simp(simp.as_uint64); 421 422 hv_get_siefp(siefp.as_uint64); 423 siefp.siefp_enabled = 0; 424 siefp.base_siefp_gpa = 0; 425 426 hv_set_siefp(siefp.as_uint64); 427 428 /* Disable the global synic bit */ 429 hv_get_synic_state(sctrl.as_uint64); 430 sctrl.enable = 0; 431 hv_set_synic_state(sctrl.as_uint64); 432 433 return 0; 434 } 435