linux/arch/x86/hyperv/hv_init.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * X86 specific Hyper-V initialization code.
   4 *
   5 * Copyright (C) 2016, Microsoft, Inc.
   6 *
   7 * Author : K. Y. Srinivasan <kys@microsoft.com>
   8 */
   9
  10#include <linux/acpi.h>
  11#include <linux/efi.h>
  12#include <linux/types.h>
  13#include <linux/bitfield.h>
  14#include <asm/apic.h>
  15#include <asm/desc.h>
  16#include <asm/hypervisor.h>
  17#include <asm/hyperv-tlfs.h>
  18#include <asm/mshyperv.h>
  19#include <asm/idtentry.h>
  20#include <linux/kexec.h>
  21#include <linux/version.h>
  22#include <linux/vmalloc.h>
  23#include <linux/mm.h>
  24#include <linux/hyperv.h>
  25#include <linux/slab.h>
  26#include <linux/kernel.h>
  27#include <linux/cpuhotplug.h>
  28#include <linux/syscore_ops.h>
  29#include <clocksource/hyperv_timer.h>
  30#include <linux/highmem.h>
  31
  32int hyperv_init_cpuhp;
  33u64 hv_current_partition_id = ~0ull;
  34EXPORT_SYMBOL_GPL(hv_current_partition_id);
  35
  36void *hv_hypercall_pg;
  37EXPORT_SYMBOL_GPL(hv_hypercall_pg);
  38
  39/* Storage to save the hypercall page temporarily for hibernation */
  40static void *hv_hypercall_pg_saved;
  41
  42u32 *hv_vp_index;
  43EXPORT_SYMBOL_GPL(hv_vp_index);
  44
  45struct hv_vp_assist_page **hv_vp_assist_page;
  46EXPORT_SYMBOL_GPL(hv_vp_assist_page);
  47
  48void  __percpu **hyperv_pcpu_input_arg;
  49EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
  50
  51void  __percpu **hyperv_pcpu_output_arg;
  52EXPORT_SYMBOL_GPL(hyperv_pcpu_output_arg);
  53
  54u32 hv_max_vp_index;
  55EXPORT_SYMBOL_GPL(hv_max_vp_index);
  56
  57static int hv_cpu_init(unsigned int cpu)
  58{
  59        u64 msr_vp_index;
  60        struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()];
  61        void **input_arg;
  62        struct page *pg;
  63
  64        /* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
  65        pg = alloc_pages(irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL, hv_root_partition ? 1 : 0);
  66        if (unlikely(!pg))
  67                return -ENOMEM;
  68
  69        input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
  70        *input_arg = page_address(pg);
  71        if (hv_root_partition) {
  72                void **output_arg;
  73
  74                output_arg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
  75                *output_arg = page_address(pg + 1);
  76        }
  77
  78        msr_vp_index = hv_get_register(HV_REGISTER_VP_INDEX);
  79
  80        hv_vp_index[smp_processor_id()] = msr_vp_index;
  81
  82        if (msr_vp_index > hv_max_vp_index)
  83                hv_max_vp_index = msr_vp_index;
  84
  85        if (!hv_vp_assist_page)
  86                return 0;
  87
  88        /*
  89         * The VP ASSIST PAGE is an "overlay" page (see Hyper-V TLFS's Section
  90         * 5.2.1 "GPA Overlay Pages"). Here it must be zeroed out to make sure
  91         * we always write the EOI MSR in hv_apic_eoi_write() *after* the
  92         * EOI optimization is disabled in hv_cpu_die(), otherwise a CPU may
  93         * not be stopped in the case of CPU offlining and the VM will hang.
  94         */
  95        if (!*hvp) {
  96                *hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO);
  97        }
  98
  99        if (*hvp) {
 100                u64 val;
 101
 102                val = vmalloc_to_pfn(*hvp);
 103                val = (val << HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT) |
 104                        HV_X64_MSR_VP_ASSIST_PAGE_ENABLE;
 105
 106                wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, val);
 107        }
 108
 109        return 0;
 110}
 111
 112static void (*hv_reenlightenment_cb)(void);
 113
 114static void hv_reenlightenment_notify(struct work_struct *dummy)
 115{
 116        struct hv_tsc_emulation_status emu_status;
 117
 118        rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
 119
 120        /* Don't issue the callback if TSC accesses are not emulated */
 121        if (hv_reenlightenment_cb && emu_status.inprogress)
 122                hv_reenlightenment_cb();
 123}
 124static DECLARE_DELAYED_WORK(hv_reenlightenment_work, hv_reenlightenment_notify);
 125
 126void hyperv_stop_tsc_emulation(void)
 127{
 128        u64 freq;
 129        struct hv_tsc_emulation_status emu_status;
 130
 131        rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
 132        emu_status.inprogress = 0;
 133        wrmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
 134
 135        rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
 136        tsc_khz = div64_u64(freq, 1000);
 137}
 138EXPORT_SYMBOL_GPL(hyperv_stop_tsc_emulation);
 139
 140static inline bool hv_reenlightenment_available(void)
 141{
 142        /*
 143         * Check for required features and privileges to make TSC frequency
 144         * change notifications work.
 145         */
 146        return ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
 147                ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE &&
 148                ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT;
 149}
 150
 151DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_reenlightenment)
 152{
 153        ack_APIC_irq();
 154        inc_irq_stat(irq_hv_reenlightenment_count);
 155        schedule_delayed_work(&hv_reenlightenment_work, HZ/10);
 156}
 157
 158void set_hv_tscchange_cb(void (*cb)(void))
 159{
 160        struct hv_reenlightenment_control re_ctrl = {
 161                .vector = HYPERV_REENLIGHTENMENT_VECTOR,
 162                .enabled = 1,
 163                .target_vp = hv_vp_index[smp_processor_id()]
 164        };
 165        struct hv_tsc_emulation_control emu_ctrl = {.enabled = 1};
 166
 167        if (!hv_reenlightenment_available()) {
 168                pr_warn("Hyper-V: reenlightenment support is unavailable\n");
 169                return;
 170        }
 171
 172        hv_reenlightenment_cb = cb;
 173
 174        /* Make sure callback is registered before we write to MSRs */
 175        wmb();
 176
 177        wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
 178        wrmsrl(HV_X64_MSR_TSC_EMULATION_CONTROL, *((u64 *)&emu_ctrl));
 179}
 180EXPORT_SYMBOL_GPL(set_hv_tscchange_cb);
 181
 182void clear_hv_tscchange_cb(void)
 183{
 184        struct hv_reenlightenment_control re_ctrl;
 185
 186        if (!hv_reenlightenment_available())
 187                return;
 188
 189        rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
 190        re_ctrl.enabled = 0;
 191        wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
 192
 193        hv_reenlightenment_cb = NULL;
 194}
 195EXPORT_SYMBOL_GPL(clear_hv_tscchange_cb);
 196
 197static int hv_cpu_die(unsigned int cpu)
 198{
 199        struct hv_reenlightenment_control re_ctrl;
 200        unsigned int new_cpu;
 201        unsigned long flags;
 202        void **input_arg;
 203        void *pg;
 204
 205        local_irq_save(flags);
 206        input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
 207        pg = *input_arg;
 208        *input_arg = NULL;
 209
 210        if (hv_root_partition) {
 211                void **output_arg;
 212
 213                output_arg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
 214                *output_arg = NULL;
 215        }
 216
 217        local_irq_restore(flags);
 218
 219        free_pages((unsigned long)pg, hv_root_partition ? 1 : 0);
 220
 221        if (hv_vp_assist_page && hv_vp_assist_page[cpu])
 222                wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, 0);
 223
 224        if (hv_reenlightenment_cb == NULL)
 225                return 0;
 226
 227        rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
 228        if (re_ctrl.target_vp == hv_vp_index[cpu]) {
 229                /*
 230                 * Reassign reenlightenment notifications to some other online
 231                 * CPU or just disable the feature if there are no online CPUs
 232                 * left (happens on hibernation).
 233                 */
 234                new_cpu = cpumask_any_but(cpu_online_mask, cpu);
 235
 236                if (new_cpu < nr_cpu_ids)
 237                        re_ctrl.target_vp = hv_vp_index[new_cpu];
 238                else
 239                        re_ctrl.enabled = 0;
 240
 241                wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
 242        }
 243
 244        return 0;
 245}
 246
 247static int __init hv_pci_init(void)
 248{
 249        int gen2vm = efi_enabled(EFI_BOOT);
 250
 251        /*
 252         * For Generation-2 VM, we exit from pci_arch_init() by returning 0.
 253         * The purpose is to suppress the harmless warning:
 254         * "PCI: Fatal: No config space access function found"
 255         */
 256        if (gen2vm)
 257                return 0;
 258
 259        /* For Generation-1 VM, we'll proceed in pci_arch_init().  */
 260        return 1;
 261}
 262
 263static int hv_suspend(void)
 264{
 265        union hv_x64_msr_hypercall_contents hypercall_msr;
 266        int ret;
 267
 268        if (hv_root_partition)
 269                return -EPERM;
 270
 271        /*
 272         * Reset the hypercall page as it is going to be invalidated
 273         * across hibernation. Setting hv_hypercall_pg to NULL ensures
 274         * that any subsequent hypercall operation fails safely instead of
 275         * crashing due to an access of an invalid page. The hypercall page
 276         * pointer is restored on resume.
 277         */
 278        hv_hypercall_pg_saved = hv_hypercall_pg;
 279        hv_hypercall_pg = NULL;
 280
 281        /* Disable the hypercall page in the hypervisor */
 282        rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 283        hypercall_msr.enable = 0;
 284        wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 285
 286        ret = hv_cpu_die(0);
 287        return ret;
 288}
 289
 290static void hv_resume(void)
 291{
 292        union hv_x64_msr_hypercall_contents hypercall_msr;
 293        int ret;
 294
 295        ret = hv_cpu_init(0);
 296        WARN_ON(ret);
 297
 298        /* Re-enable the hypercall page */
 299        rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 300        hypercall_msr.enable = 1;
 301        hypercall_msr.guest_physical_address =
 302                vmalloc_to_pfn(hv_hypercall_pg_saved);
 303        wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 304
 305        hv_hypercall_pg = hv_hypercall_pg_saved;
 306        hv_hypercall_pg_saved = NULL;
 307
 308        /*
 309         * Reenlightenment notifications are disabled by hv_cpu_die(0),
 310         * reenable them here if hv_reenlightenment_cb was previously set.
 311         */
 312        if (hv_reenlightenment_cb)
 313                set_hv_tscchange_cb(hv_reenlightenment_cb);
 314}
 315
 316/* Note: when the ops are called, only CPU0 is online and IRQs are disabled. */
 317static struct syscore_ops hv_syscore_ops = {
 318        .suspend        = hv_suspend,
 319        .resume         = hv_resume,
 320};
 321
 322static void (* __initdata old_setup_percpu_clockev)(void);
 323
 324static void __init hv_stimer_setup_percpu_clockev(void)
 325{
 326        /*
 327         * Ignore any errors in setting up stimer clockevents
 328         * as we can run with the LAPIC timer as a fallback.
 329         */
 330        (void)hv_stimer_alloc(false);
 331
 332        /*
 333         * Still register the LAPIC timer, because the direct-mode STIMER is
 334         * not supported by old versions of Hyper-V. This also allows users
 335         * to switch to LAPIC timer via /sys, if they want to.
 336         */
 337        if (old_setup_percpu_clockev)
 338                old_setup_percpu_clockev();
 339}
 340
 341static void __init hv_get_partition_id(void)
 342{
 343        struct hv_get_partition_id *output_page;
 344        u64 status;
 345        unsigned long flags;
 346
 347        local_irq_save(flags);
 348        output_page = *this_cpu_ptr(hyperv_pcpu_output_arg);
 349        status = hv_do_hypercall(HVCALL_GET_PARTITION_ID, NULL, output_page);
 350        if (!hv_result_success(status)) {
 351                /* No point in proceeding if this failed */
 352                pr_err("Failed to get partition ID: %lld\n", status);
 353                BUG();
 354        }
 355        hv_current_partition_id = output_page->partition_id;
 356        local_irq_restore(flags);
 357}
 358
 359/*
 360 * This function is to be invoked early in the boot sequence after the
 361 * hypervisor has been detected.
 362 *
 363 * 1. Setup the hypercall page.
 364 * 2. Register Hyper-V specific clocksource.
 365 * 3. Setup Hyper-V specific APIC entry points.
 366 */
 367void __init hyperv_init(void)
 368{
 369        u64 guest_id, required_msrs;
 370        union hv_x64_msr_hypercall_contents hypercall_msr;
 371        int cpuhp, i;
 372
 373        if (x86_hyper_type != X86_HYPER_MS_HYPERV)
 374                return;
 375
 376        /* Absolutely required MSRs */
 377        required_msrs = HV_MSR_HYPERCALL_AVAILABLE |
 378                HV_MSR_VP_INDEX_AVAILABLE;
 379
 380        if ((ms_hyperv.features & required_msrs) != required_msrs)
 381                return;
 382
 383        /*
 384         * Allocate the per-CPU state for the hypercall input arg.
 385         * If this allocation fails, we will not be able to setup
 386         * (per-CPU) hypercall input page and thus this failure is
 387         * fatal on Hyper-V.
 388         */
 389        hyperv_pcpu_input_arg = alloc_percpu(void  *);
 390
 391        BUG_ON(hyperv_pcpu_input_arg == NULL);
 392
 393        /* Allocate the per-CPU state for output arg for root */
 394        if (hv_root_partition) {
 395                hyperv_pcpu_output_arg = alloc_percpu(void *);
 396                BUG_ON(hyperv_pcpu_output_arg == NULL);
 397        }
 398
 399        /* Allocate percpu VP index */
 400        hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index),
 401                                    GFP_KERNEL);
 402        if (!hv_vp_index)
 403                return;
 404
 405        for (i = 0; i < num_possible_cpus(); i++)
 406                hv_vp_index[i] = VP_INVAL;
 407
 408        hv_vp_assist_page = kcalloc(num_possible_cpus(),
 409                                    sizeof(*hv_vp_assist_page), GFP_KERNEL);
 410        if (!hv_vp_assist_page) {
 411                ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
 412                goto free_vp_index;
 413        }
 414
 415        cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
 416                                  hv_cpu_init, hv_cpu_die);
 417        if (cpuhp < 0)
 418                goto free_vp_assist_page;
 419
 420        /*
 421         * Setup the hypercall page and enable hypercalls.
 422         * 1. Register the guest ID
 423         * 2. Enable the hypercall and register the hypercall page
 424         */
 425        guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
 426        wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
 427
 428        hv_hypercall_pg = __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START,
 429                        VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_ROX,
 430                        VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
 431                        __builtin_return_address(0));
 432        if (hv_hypercall_pg == NULL) {
 433                wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
 434                goto remove_cpuhp_state;
 435        }
 436
 437        rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 438        hypercall_msr.enable = 1;
 439
 440        if (hv_root_partition) {
 441                struct page *pg;
 442                void *src, *dst;
 443
 444                /*
 445                 * For the root partition, the hypervisor will set up its
 446                 * hypercall page. The hypervisor guarantees it will not show
 447                 * up in the root's address space. The root can't change the
 448                 * location of the hypercall page.
 449                 *
 450                 * Order is important here. We must enable the hypercall page
 451                 * so it is populated with code, then copy the code to an
 452                 * executable page.
 453                 */
 454                wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 455
 456                pg = vmalloc_to_page(hv_hypercall_pg);
 457                dst = kmap(pg);
 458                src = memremap(hypercall_msr.guest_physical_address << PAGE_SHIFT, PAGE_SIZE,
 459                                MEMREMAP_WB);
 460                BUG_ON(!(src && dst));
 461                memcpy(dst, src, HV_HYP_PAGE_SIZE);
 462                memunmap(src);
 463                kunmap(pg);
 464        } else {
 465                hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
 466                wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 467        }
 468
 469        /*
 470         * hyperv_init() is called before LAPIC is initialized: see
 471         * apic_intr_mode_init() -> x86_platform.apic_post_init() and
 472         * apic_bsp_setup() -> setup_local_APIC(). The direct-mode STIMER
 473         * depends on LAPIC, so hv_stimer_alloc() should be called from
 474         * x86_init.timers.setup_percpu_clockev.
 475         */
 476        old_setup_percpu_clockev = x86_init.timers.setup_percpu_clockev;
 477        x86_init.timers.setup_percpu_clockev = hv_stimer_setup_percpu_clockev;
 478
 479        hv_apic_init();
 480
 481        x86_init.pci.arch_init = hv_pci_init;
 482
 483        register_syscore_ops(&hv_syscore_ops);
 484
 485        hyperv_init_cpuhp = cpuhp;
 486
 487        if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_ACCESS_PARTITION_ID)
 488                hv_get_partition_id();
 489
 490        BUG_ON(hv_root_partition && hv_current_partition_id == ~0ull);
 491
 492#ifdef CONFIG_PCI_MSI
 493        /*
 494         * If we're running as root, we want to create our own PCI MSI domain.
 495         * We can't set this in hv_pci_init because that would be too late.
 496         */
 497        if (hv_root_partition)
 498                x86_init.irqs.create_pci_msi_domain = hv_create_pci_msi_domain;
 499#endif
 500
 501        /* Query the VMs extended capability once, so that it can be cached. */
 502        hv_query_ext_cap(0);
 503        return;
 504
 505remove_cpuhp_state:
 506        cpuhp_remove_state(cpuhp);
 507free_vp_assist_page:
 508        kfree(hv_vp_assist_page);
 509        hv_vp_assist_page = NULL;
 510free_vp_index:
 511        kfree(hv_vp_index);
 512        hv_vp_index = NULL;
 513}
 514
 515/*
 516 * This routine is called before kexec/kdump, it does the required cleanup.
 517 */
 518void hyperv_cleanup(void)
 519{
 520        union hv_x64_msr_hypercall_contents hypercall_msr;
 521
 522        unregister_syscore_ops(&hv_syscore_ops);
 523
 524        /* Reset our OS id */
 525        wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
 526
 527        /*
 528         * Reset hypercall page reference before reset the page,
 529         * let hypercall operations fail safely rather than
 530         * panic the kernel for using invalid hypercall page
 531         */
 532        hv_hypercall_pg = NULL;
 533
 534        /* Reset the hypercall page */
 535        hypercall_msr.as_uint64 = 0;
 536        wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 537
 538        /* Reset the TSC page */
 539        hypercall_msr.as_uint64 = 0;
 540        wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64);
 541}
 542EXPORT_SYMBOL_GPL(hyperv_cleanup);
 543
 544void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die)
 545{
 546        static bool panic_reported;
 547        u64 guest_id;
 548
 549        if (in_die && !panic_on_oops)
 550                return;
 551
 552        /*
 553         * We prefer to report panic on 'die' chain as we have proper
 554         * registers to report, but if we miss it (e.g. on BUG()) we need
 555         * to report it on 'panic'.
 556         */
 557        if (panic_reported)
 558                return;
 559        panic_reported = true;
 560
 561        rdmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
 562
 563        wrmsrl(HV_X64_MSR_CRASH_P0, err);
 564        wrmsrl(HV_X64_MSR_CRASH_P1, guest_id);
 565        wrmsrl(HV_X64_MSR_CRASH_P2, regs->ip);
 566        wrmsrl(HV_X64_MSR_CRASH_P3, regs->ax);
 567        wrmsrl(HV_X64_MSR_CRASH_P4, regs->sp);
 568
 569        /*
 570         * Let Hyper-V know there is crash data available
 571         */
 572        wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
 573}
 574EXPORT_SYMBOL_GPL(hyperv_report_panic);
 575
 576bool hv_is_hyperv_initialized(void)
 577{
 578        union hv_x64_msr_hypercall_contents hypercall_msr;
 579
 580        /*
 581         * Ensure that we're really on Hyper-V, and not a KVM or Xen
 582         * emulation of Hyper-V
 583         */
 584        if (x86_hyper_type != X86_HYPER_MS_HYPERV)
 585                return false;
 586
 587        /*
 588         * Verify that earlier initialization succeeded by checking
 589         * that the hypercall page is setup
 590         */
 591        hypercall_msr.as_uint64 = 0;
 592        rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 593
 594        return hypercall_msr.enable;
 595}
 596EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);
 597
 598bool hv_is_hibernation_supported(void)
 599{
 600        return !hv_root_partition && acpi_sleep_state_supported(ACPI_STATE_S4);
 601}
 602EXPORT_SYMBOL_GPL(hv_is_hibernation_supported);
 603
 604enum hv_isolation_type hv_get_isolation_type(void)
 605{
 606        if (!(ms_hyperv.priv_high & HV_ISOLATION))
 607                return HV_ISOLATION_TYPE_NONE;
 608        return FIELD_GET(HV_ISOLATION_TYPE, ms_hyperv.isolation_config_b);
 609}
 610EXPORT_SYMBOL_GPL(hv_get_isolation_type);
 611
 612bool hv_is_isolation_supported(void)
 613{
 614        return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE;
 615}
 616EXPORT_SYMBOL_GPL(hv_is_isolation_supported);
 617