drivers/hv/hv.c

   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/interrupt.h>
  31 #include <linux/clockchips.h>
  32 #include <asm/hyperv.h>
  33 #include <asm/mshyperv.h>
  34 #include <asm/nospec-branch.h>
  35 #include "hyperv_vmbus.h"
  36
  37 /* The one and only */
  38 struct hv_context hv_context = {
  39         .synic_initialized      = false,
  40         .hypercall_page         = NULL,
  41 };
  42
  43 #define HV_TIMER_FREQUENCY (10 * 1000 * 1000) /* 100ns period */
  44 #define HV_MAX_MAX_DELTA_TICKS 0xffffffff
  45 #define HV_MIN_DELTA_TICKS 1
  46
  47 /*
  48  * query_hypervisor_info - Get version info of the windows hypervisor
  49  */
  50 unsigned int host_info_eax;
  51 unsigned int host_info_ebx;
  52 unsigned int host_info_ecx;
  53 unsigned int host_info_edx;
  54
  55 static int query_hypervisor_info(void)
  56 {
  57         unsigned int eax;
  58         unsigned int ebx;
  59         unsigned int ecx;
  60         unsigned int edx;
  61         unsigned int max_leaf;
  62         unsigned int op;
  63
  64         /*
  65         * Its assumed that this is called after confirming that Viridian
  66         * is present. Query id and revision.
  67         */
  68         eax = 0;
  69         ebx = 0;
  70         ecx = 0;
  71         edx = 0;
  72         op = HVCPUID_VENDOR_MAXFUNCTION;
  73         cpuid(op, &eax, &ebx, &ecx, &edx);
  74
  75         max_leaf = eax;
  76
  77         if (max_leaf >= HVCPUID_VERSION) {
  78                 eax = 0;
  79                 ebx = 0;
  80                 ecx = 0;
  81                 edx = 0;
  82                 op = HVCPUID_VERSION;
  83                 cpuid(op, &eax, &ebx, &ecx, &edx);
  84                 host_info_eax = eax;
  85                 host_info_ebx = ebx;
  86                 host_info_ecx = ecx;
  87                 host_info_edx = edx;
  88         }
  89         return max_leaf;
  90 }
  91
  92 /*
  93  * hv_do_hypercall- Invoke the specified hypercall
  94  */
  95 u64 hv_do_hypercall(u64 control, void *input, void *output)
  96 {
  97         u64 input_address = (input) ? virt_to_phys(input) : 0;
  98         u64 output_address = (output) ? virt_to_phys(output) : 0;
  99         void *hypercall_page = hv_context.hypercall_page;
 100 #ifdef CONFIG_X86_64
 101         u64 hv_status = 0;
 102
 103         if (!hypercall_page)
 104                 return (u64)ULLONG_MAX;
 105
 106         __asm__ __volatile__("mov %0, %%r8" : : "r" (output_address) : "r8");
 107         __asm__ __volatile__(CALL_NOSPEC :
 108                              "=a" (hv_status) :
 109                              "c" (control), "d" (input_address),
 110                              THUNK_TARGET(hypercall_page));
 111
 112         return hv_status;
 113
 114 #else
 115
 116         u32 control_hi = control >> 32;
 117         u32 control_lo = control & 0xFFFFFFFF;
 118         u32 hv_status_hi = 1;
 119         u32 hv_status_lo = 1;
 120         u32 input_address_hi = input_address >> 32;
 121         u32 input_address_lo = input_address & 0xFFFFFFFF;
 122         u32 output_address_hi = output_address >> 32;
 123         u32 output_address_lo = output_address & 0xFFFFFFFF;
 124
 125         if (!hypercall_page)
 126                 return (u64)ULLONG_MAX;
 127
 128         __asm__ __volatile__ (CALL_NOSPEC : "=d"(hv_status_hi),
 129                               "=a"(hv_status_lo) : "d" (control_hi),
 130                               "a" (control_lo), "b" (input_address_hi),
 131                               "c" (input_address_lo), "D"(output_address_hi),
 132                               "S"(output_address_lo),
 133                               THUNK_TARGET(hypercall_page));
 134
 135         return hv_status_lo | ((u64)hv_status_hi << 32);
 136 #endif /* !x86_64 */
 137 }
 138 EXPORT_SYMBOL_GPL(hv_do_hypercall);
 139
 140 #ifdef CONFIG_X86_64
 141 static cycle_t read_hv_clock_tsc(struct clocksource *arg)
 142 {
 143         cycle_t current_tick;
 144         struct ms_hyperv_tsc_page *tsc_pg = hv_context.tsc_page;
 145
 146         if (tsc_pg->tsc_sequence != 0) {
 147                 /*
 148                  * Use the tsc page to compute the value.
 149                  */
 150
 151                 while (1) {
 152                         cycle_t tmp;
 153                         u32 sequence = tsc_pg->tsc_sequence;
 154                         u64 cur_tsc;
 155                         u64 scale = tsc_pg->tsc_scale;
 156                         s64 offset = tsc_pg->tsc_offset;
 157
 158                         rdtscll(cur_tsc);
 159                         /* current_tick = ((cur_tsc *scale) >> 64) + offset */
 160                         asm("mulq %3"
 161                                 : "=d" (current_tick), "=a" (tmp)
 162                                 : "a" (cur_tsc), "r" (scale));
 163
 164                         current_tick += offset;
 165                         if (tsc_pg->tsc_sequence == sequence)
 166                                 return current_tick;
 167
 168                         if (tsc_pg->tsc_sequence != 0)
 169                                 continue;
 170                         /*
 171                          * Fallback using MSR method.
 172                          */
 173                         break;
 174                 }
 175         }
 176         rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
 177         return current_tick;
 178 }
 179
 180 static struct clocksource hyperv_cs_tsc = {
 181                 .name           = "hyperv_clocksource_tsc_page",
 182                 .rating         = 425,
 183                 .read           = read_hv_clock_tsc,
 184                 .mask           = CLOCKSOURCE_MASK(64),
 185                 .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 186 };
 187 #endif
 188
 189
 190 /*
 191  * hv_init - Main initialization routine.
 192  *
 193  * This routine must be called before any other routines in here are called
 194  */
 195 int hv_init(void)
 196 {
 197         int max_leaf;
 198         union hv_x64_msr_hypercall_contents hypercall_msr;
 199         void *virtaddr = NULL;
 200
 201         memset(hv_context.synic_event_page, 0, sizeof(void *) * NR_CPUS);
 202         memset(hv_context.synic_message_page, 0,
 203                sizeof(void *) * NR_CPUS);
 204         memset(hv_context.post_msg_page, 0,
 205                sizeof(void *) * NR_CPUS);
 206         memset(hv_context.vp_index, 0,
 207                sizeof(int) * NR_CPUS);
 208         memset(hv_context.event_dpc, 0,
 209                sizeof(void *) * NR_CPUS);
 210         memset(hv_context.msg_dpc, 0,
 211                sizeof(void *) * NR_CPUS);
 212         memset(hv_context.clk_evt, 0,
 213                sizeof(void *) * NR_CPUS);
 214
 215         max_leaf = query_hypervisor_info();
 216
 217         /*
 218          * Write our OS ID.
 219          */
 220         hv_context.guestid = generate_guest_id(0, LINUX_VERSION_CODE, 0);
 221         wrmsrl(HV_X64_MSR_GUEST_OS_ID, hv_context.guestid);
 222
 223         /* See if the hypercall page is already set */
 224         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 225
 226         virtaddr = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX);
 227
 228         if (!virtaddr)
 229                 goto cleanup;
 230
 231         hypercall_msr.enable = 1;
 232
 233         hypercall_msr.guest_physical_address = vmalloc_to_pfn(virtaddr);
 234         wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 235
 236         /* Confirm that hypercall page did get setup. */
 237         hypercall_msr.as_uint64 = 0;
 238         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 239
 240         if (!hypercall_msr.enable)
 241                 goto cleanup;
 242
 243         hv_context.hypercall_page = virtaddr;
 244
 245 #ifdef CONFIG_X86_64
 246         if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) {
 247                 union hv_x64_msr_hypercall_contents tsc_msr;
 248                 void *va_tsc;
 249
 250                 va_tsc = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
 251                 if (!va_tsc)
 252                         goto cleanup;
 253                 hv_context.tsc_page = va_tsc;
 254
 255                 rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
 256
 257                 tsc_msr.enable = 1;
 258                 tsc_msr.guest_physical_address = vmalloc_to_pfn(va_tsc);
 259
 260                 wrmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
 261                 clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
 262         }
 263 #endif
 264         return 0;
 265
 266 cleanup:
 267         if (virtaddr) {
 268                 if (hypercall_msr.enable) {
 269                         hypercall_msr.as_uint64 = 0;
 270                         wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 271                 }
 272
 273                 vfree(virtaddr);
 274         }
 275
 276         return -ENOTSUPP;
 277 }
 278
 279 /*
 280  * hv_cleanup - Cleanup routine.
 281  *
 282  * This routine is called normally during driver unloading or exiting.
 283  */
 284 void hv_cleanup(bool crash)
 285 {
 286         union hv_x64_msr_hypercall_contents hypercall_msr;
 287
 288         /* Reset our OS id */
 289         wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
 290
 291         if (hv_context.hypercall_page) {
 292                 hypercall_msr.as_uint64 = 0;
 293                 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 294                 if (!crash)
 295                         vfree(hv_context.hypercall_page);
 296                 hv_context.hypercall_page = NULL;
 297         }
 298
 299 #ifdef CONFIG_X86_64
 300         /*
 301          * Cleanup the TSC page based CS.
 302          */
 303         if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) {
 304                 /*
 305                  * Crash can happen in an interrupt context and unregistering
 306                  * a clocksource is impossible and redundant in this case.
 307                  */
 308                 if (!oops_in_progress) {
 309                         clocksource_change_rating(&hyperv_cs_tsc, 10);
 310                         clocksource_unregister(&hyperv_cs_tsc);
 311                 }
 312
 313                 hypercall_msr.as_uint64 = 0;
 314                 wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64);
 315                 if (!crash) {
 316                         vfree(hv_context.tsc_page);
 317                         hv_context.tsc_page = NULL;
 318                 }
 319         }
 320 #endif
 321 }
 322
 323 /*
 324  * hv_post_message - Post a message using the hypervisor message IPC.
 325  *
 326  * This involves a hypercall.
 327  */
 328 int hv_post_message(union hv_connection_id connection_id,
 329                   enum hv_message_type message_type,
 330                   void *payload, size_t payload_size)
 331 {
 332
 333         struct hv_input_post_message *aligned_msg;
 334         u64 status;
 335
 336         if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
 337                 return -EMSGSIZE;
 338
 339         aligned_msg = (struct hv_input_post_message *)
 340                         hv_context.post_msg_page[get_cpu()];
 341
 342         aligned_msg->connectionid = connection_id;
 343         aligned_msg->reserved = 0;
 344         aligned_msg->message_type = message_type;
 345         aligned_msg->payload_size = payload_size;
 346         memcpy((void *)aligned_msg->payload, payload, payload_size);
 347
 348         status = hv_do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL);
 349
 350         put_cpu();
 351         return status & 0xFFFF;
 352 }
 353
 354 static int hv_ce_set_next_event(unsigned long delta,
 355                                 struct clock_event_device *evt)
 356 {
 357         cycle_t current_tick;
 358
 359         WARN_ON(!clockevent_state_oneshot(evt));
 360
 361         rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
 362         current_tick += delta;
 363         wrmsrl(HV_X64_MSR_STIMER0_COUNT, current_tick);
 364         return 0;
 365 }
 366
 367 static int hv_ce_shutdown(struct clock_event_device *evt)
 368 {
 369         wrmsrl(HV_X64_MSR_STIMER0_COUNT, 0);
 370         wrmsrl(HV_X64_MSR_STIMER0_CONFIG, 0);
 371
 372         return 0;
 373 }
 374
 375 static int hv_ce_set_oneshot(struct clock_event_device *evt)
 376 {
 377         union hv_timer_config timer_cfg;
 378
 379         timer_cfg.enable = 1;
 380         timer_cfg.auto_enable = 1;
 381         timer_cfg.sintx = VMBUS_MESSAGE_SINT;
 382         wrmsrl(HV_X64_MSR_STIMER0_CONFIG, timer_cfg.as_uint64);
 383
 384         return 0;
 385 }
 386
 387 static void hv_init_clockevent_device(struct clock_event_device *dev, int cpu)
 388 {
 389         dev->name = "Hyper-V clockevent";
 390         dev->features = CLOCK_EVT_FEAT_ONESHOT;
 391         dev->cpumask = cpumask_of(cpu);
 392         dev->rating = 1000;
 393         /*
 394          * Avoid settint dev->owner = THIS_MODULE deliberately as doing so will
 395          * result in clockevents_config_and_register() taking additional
 396          * references to the hv_vmbus module making it impossible to unload.
 397          */
 398
 399         dev->set_state_shutdown = hv_ce_shutdown;
 400         dev->set_state_oneshot = hv_ce_set_oneshot;
 401         dev->set_next_event = hv_ce_set_next_event;
 402 }
 403
 404
 405 int hv_synic_alloc(void)
 406 {
 407         size_t size = sizeof(struct tasklet_struct);
 408         size_t ced_size = sizeof(struct clock_event_device);
 409         int cpu;
 410
 411         hv_context.hv_numa_map = kzalloc(sizeof(struct cpumask) * nr_node_ids,
 412                                          GFP_ATOMIC);
 413         if (hv_context.hv_numa_map == NULL) {
 414                 pr_err("Unable to allocate NUMA map\n");
 415                 goto err;
 416         }
 417
 418         for_each_present_cpu(cpu) {
 419                 hv_context.event_dpc[cpu] = kmalloc(size, GFP_ATOMIC);
 420                 if (hv_context.event_dpc[cpu] == NULL) {
 421                         pr_err("Unable to allocate event dpc\n");
 422                         goto err;
 423                 }
 424                 tasklet_init(hv_context.event_dpc[cpu], vmbus_on_event, cpu);
 425
 426                 hv_context.msg_dpc[cpu] = kmalloc(size, GFP_ATOMIC);
 427                 if (hv_context.msg_dpc[cpu] == NULL) {
 428                         pr_err("Unable to allocate event dpc\n");
 429                         goto err;
 430                 }
 431                 tasklet_init(hv_context.msg_dpc[cpu], vmbus_on_msg_dpc, cpu);
 432
 433                 hv_context.clk_evt[cpu] = kzalloc(ced_size, GFP_ATOMIC);
 434                 if (hv_context.clk_evt[cpu] == NULL) {
 435                         pr_err("Unable to allocate clock event device\n");
 436                         goto err;
 437                 }
 438
 439                 hv_init_clockevent_device(hv_context.clk_evt[cpu], cpu);
 440
 441                 hv_context.synic_message_page[cpu] =
 442                         (void *)get_zeroed_page(GFP_ATOMIC);
 443
 444                 if (hv_context.synic_message_page[cpu] == NULL) {
 445                         pr_err("Unable to allocate SYNIC message page\n");
 446                         goto err;
 447                 }
 448
 449                 hv_context.synic_event_page[cpu] =
 450                         (void *)get_zeroed_page(GFP_ATOMIC);
 451
 452                 if (hv_context.synic_event_page[cpu] == NULL) {
 453                         pr_err("Unable to allocate SYNIC event page\n");
 454                         goto err;
 455                 }
 456
 457                 hv_context.post_msg_page[cpu] =
 458                         (void *)get_zeroed_page(GFP_ATOMIC);
 459
 460                 if (hv_context.post_msg_page[cpu] == NULL) {
 461                         pr_err("Unable to allocate post msg page\n");
 462                         goto err;
 463                 }
 464
 465                 INIT_LIST_HEAD(&hv_context.percpu_list[cpu]);
 466         }
 467
 468         return 0;
 469 err:
 470         return -ENOMEM;
 471 }
 472
 473 static void hv_synic_free_cpu(int cpu)
 474 {
 475         kfree(hv_context.event_dpc[cpu]);
 476         kfree(hv_context.msg_dpc[cpu]);
 477         kfree(hv_context.clk_evt[cpu]);
 478         if (hv_context.synic_event_page[cpu])
 479                 free_page((unsigned long)hv_context.synic_event_page[cpu]);
 480         if (hv_context.synic_message_page[cpu])
 481                 free_page((unsigned long)hv_context.synic_message_page[cpu]);
 482         if (hv_context.post_msg_page[cpu])
 483                 free_page((unsigned long)hv_context.post_msg_page[cpu]);
 484 }
 485
 486 void hv_synic_free(void)
 487 {
 488         int cpu;
 489
 490         kfree(hv_context.hv_numa_map);
 491         for_each_present_cpu(cpu)
 492                 hv_synic_free_cpu(cpu);
 493 }
 494
 495 /*
 496  * hv_synic_init - Initialize the Synthethic Interrupt Controller.
 497  *
 498  * If it is already initialized by another entity (ie x2v shim), we need to
 499  * retrieve the initialized message and event pages.  Otherwise, we create and
 500  * initialize the message and event pages.
 501  */
 502 void hv_synic_init(void *arg)
 503 {
 504         u64 version;
 505         union hv_synic_simp simp;
 506         union hv_synic_siefp siefp;
 507         union hv_synic_sint shared_sint;
 508         union hv_synic_scontrol sctrl;
 509         u64 vp_index;
 510
 511         int cpu = smp_processor_id();
 512
 513         if (!hv_context.hypercall_page)
 514                 return;
 515
 516         /* Check the version */
 517         rdmsrl(HV_X64_MSR_SVERSION, version);
 518
 519         /* Setup the Synic's message page */
 520         rdmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
 521         simp.simp_enabled = 1;
 522         simp.base_simp_gpa = virt_to_phys(hv_context.synic_message_page[cpu])
 523                 >> PAGE_SHIFT;
 524
 525         wrmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
 526
 527         /* Setup the Synic's event page */
 528         rdmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
 529         siefp.siefp_enabled = 1;
 530         siefp.base_siefp_gpa = virt_to_phys(hv_context.synic_event_page[cpu])
 531                 >> PAGE_SHIFT;
 532
 533         wrmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
 534
 535         /* Setup the shared SINT. */
 536         rdmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
 537
 538         shared_sint.as_uint64 = 0;
 539         shared_sint.vector = HYPERVISOR_CALLBACK_VECTOR;
 540         shared_sint.masked = false;
 541         shared_sint.auto_eoi = true;
 542
 543         wrmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
 544
 545         /* Enable the global synic bit */
 546         rdmsrl(HV_X64_MSR_SCONTROL, sctrl.as_uint64);
 547         sctrl.enable = 1;
 548
 549         wrmsrl(HV_X64_MSR_SCONTROL, sctrl.as_uint64);
 550
 551         hv_context.synic_initialized = true;
 552
 553         /*
 554          * Setup the mapping between Hyper-V's notion
 555          * of cpuid and Linux' notion of cpuid.
 556          * This array will be indexed using Linux cpuid.
 557          */
 558         rdmsrl(HV_X64_MSR_VP_INDEX, vp_index);
 559         hv_context.vp_index[cpu] = (u32)vp_index;
 560
 561         /*
 562          * Register the per-cpu clockevent source.
 563          */
 564         if (ms_hyperv.features & HV_X64_MSR_SYNTIMER_AVAILABLE)
 565                 clockevents_config_and_register(hv_context.clk_evt[cpu],
 566                                                 HV_TIMER_FREQUENCY,
 567                                                 HV_MIN_DELTA_TICKS,
 568                                                 HV_MAX_MAX_DELTA_TICKS);
 569         return;
 570 }
 571
 572 /*
 573  * hv_synic_clockevents_cleanup - Cleanup clockevent devices
 574  */
 575 void hv_synic_clockevents_cleanup(void)
 576 {
 577         int cpu;
 578
 579         if (!(ms_hyperv.features & HV_X64_MSR_SYNTIMER_AVAILABLE))
 580                 return;
 581
 582         for_each_online_cpu(cpu)
 583                 clockevents_unbind_device(hv_context.clk_evt[cpu], cpu);
 584 }
 585
 586 /*
 587  * hv_synic_cleanup - Cleanup routine for hv_synic_init().
 588  */
 589 void hv_synic_cleanup(void *arg)
 590 {
 591         union hv_synic_sint shared_sint;
 592         union hv_synic_simp simp;
 593         union hv_synic_siefp siefp;
 594         union hv_synic_scontrol sctrl;
 595         int cpu = smp_processor_id();
 596
 597         if (!hv_context.synic_initialized)
 598                 return;
 599
 600         /* Turn off clockevent device */
 601         if (ms_hyperv.features & HV_X64_MSR_SYNTIMER_AVAILABLE)
 602                 hv_ce_shutdown(hv_context.clk_evt[cpu]);
 603
 604         rdmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
 605
 606         shared_sint.masked = 1;
 607
 608         /* Need to correctly cleanup in the case of SMP!!! */
 609         /* Disable the interrupt */
 610         wrmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
 611
 612         rdmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
 613         simp.simp_enabled = 0;
 614         simp.base_simp_gpa = 0;
 615
 616         wrmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
 617
 618         rdmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
 619         siefp.siefp_enabled = 0;
 620         siefp.base_siefp_gpa = 0;
 621
 622         wrmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
 623
 624         /* Disable the global synic bit */
 625         rdmsrl(HV_X64_MSR_SCONTROL, sctrl.as_uint64);
 626         sctrl.enable = 0;
 627         wrmsrl(HV_X64_MSR_SCONTROL, sctrl.as_uint64);
 628 }