arch/x86/hyperv/hv_init.c

   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 #define pr_fmt(fmt)  "Hyper-V: " fmt
  11
  12 #include <linux/efi.h>
  13 #include <linux/types.h>
  14 #include <linux/bitfield.h>
  15 #include <linux/io.h>
  16 #include <asm/apic.h>
  17 #include <asm/desc.h>
  18 #include <asm/sev.h>
  19 #include <asm/ibt.h>
  20 #include <asm/hypervisor.h>
  21 #include <asm/hyperv-tlfs.h>
  22 #include <asm/mshyperv.h>
  23 #include <asm/idtentry.h>
  24 #include <asm/set_memory.h>
  25 #include <linux/kexec.h>
  26 #include <linux/version.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/mm.h>
  29 #include <linux/hyperv.h>
  30 #include <linux/slab.h>
  31 #include <linux/kernel.h>
  32 #include <linux/cpuhotplug.h>
  33 #include <linux/syscore_ops.h>
  34 #include <clocksource/hyperv_timer.h>
  35 #include <linux/highmem.h>
  36
  37 int hyperv_init_cpuhp;
  38 u64 hv_current_partition_id = ~0ull;
  39 EXPORT_SYMBOL_GPL(hv_current_partition_id);
  40
  41 void *hv_hypercall_pg;
  42 EXPORT_SYMBOL_GPL(hv_hypercall_pg);
  43
  44 union hv_ghcb * __percpu *hv_ghcb_pg;
  45
  46 /* Storage to save the hypercall page temporarily for hibernation */
  47 static void *hv_hypercall_pg_saved;
  48
  49 struct hv_vp_assist_page **hv_vp_assist_page;
  50 EXPORT_SYMBOL_GPL(hv_vp_assist_page);
  51
  52 static int hyperv_init_ghcb(void)
  53 {
  54         u64 ghcb_gpa;
  55         void *ghcb_va;
  56         void **ghcb_base;
  57
  58         if (!ms_hyperv.paravisor_present || !hv_isolation_type_snp())
  59                 return 0;
  60
  61         if (!hv_ghcb_pg)
  62                 return -EINVAL;
  63
  64         /*
  65          * GHCB page is allocated by paravisor. The address
  66          * returned by MSR_AMD64_SEV_ES_GHCB is above shared
  67          * memory boundary and map it here.
  68          */
  69         rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa);
  70
  71         /* Mask out vTOM bit. ioremap_cache() maps decrypted */
  72         ghcb_gpa &= ~ms_hyperv.shared_gpa_boundary;
  73         ghcb_va = (void *)ioremap_cache(ghcb_gpa, HV_HYP_PAGE_SIZE);
  74         if (!ghcb_va)
  75                 return -ENOMEM;
  76
  77         ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
  78         *ghcb_base = ghcb_va;
  79
  80         return 0;
  81 }
  82
  83 static int hv_cpu_init(unsigned int cpu)
  84 {
  85         union hv_vp_assist_msr_contents msr = { 0 };
  86         struct hv_vp_assist_page **hvp;
  87         int ret;
  88
  89         ret = hv_common_cpu_init(cpu);
  90         if (ret)
  91                 return ret;
  92
  93         if (!hv_vp_assist_page)
  94                 return 0;
  95
  96         hvp = &hv_vp_assist_page[cpu];
  97         if (hv_root_partition) {
  98                 /*
  99                  * For root partition we get the hypervisor provided VP assist
 100                  * page, instead of allocating a new page.
 101                  */
 102                 rdmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
 103                 *hvp = memremap(msr.pfn << HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT,
 104                                 PAGE_SIZE, MEMREMAP_WB);
 105         } else {
 106                 /*
 107                  * The VP assist page is an "overlay" page (see Hyper-V TLFS's
 108                  * Section 5.2.1 "GPA Overlay Pages"). Here it must be zeroed
 109                  * out to make sure we always write the EOI MSR in
 110                  * hv_apic_eoi_write() *after* the EOI optimization is disabled
 111                  * in hv_cpu_die(), otherwise a CPU may not be stopped in the
 112                  * case of CPU offlining and the VM will hang.
 113                  */
 114                 if (!*hvp) {
 115                         *hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO);
 116
 117                         /*
 118                          * Hyper-V should never specify a VM that is a Confidential
 119                          * VM and also running in the root partition. Root partition
 120                          * is blocked to run in Confidential VM. So only decrypt assist
 121                          * page in non-root partition here.
 122                          */
 123                         if (*hvp && !ms_hyperv.paravisor_present && hv_isolation_type_snp()) {
 124                                 WARN_ON_ONCE(set_memory_decrypted((unsigned long)(*hvp), 1));
 125                                 memset(*hvp, 0, PAGE_SIZE);
 126                         }
 127                 }
 128
 129                 if (*hvp)
 130                         msr.pfn = vmalloc_to_pfn(*hvp);
 131
 132         }
 133         if (!WARN_ON(!(*hvp))) {
 134                 msr.enable = 1;
 135                 wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
 136         }
 137
 138         return hyperv_init_ghcb();
 139 }
 140
 141 static void (*hv_reenlightenment_cb)(void);
 142
 143 static void hv_reenlightenment_notify(struct work_struct *dummy)
 144 {
 145         struct hv_tsc_emulation_status emu_status;
 146
 147         rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
 148
 149         /* Don't issue the callback if TSC accesses are not emulated */
 150         if (hv_reenlightenment_cb && emu_status.inprogress)
 151                 hv_reenlightenment_cb();
 152 }
 153 static DECLARE_DELAYED_WORK(hv_reenlightenment_work, hv_reenlightenment_notify);
 154
 155 void hyperv_stop_tsc_emulation(void)
 156 {
 157         u64 freq;
 158         struct hv_tsc_emulation_status emu_status;
 159
 160         rdmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
 161         emu_status.inprogress = 0;
 162         wrmsrl(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
 163
 164         rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
 165         tsc_khz = div64_u64(freq, 1000);
 166 }
 167 EXPORT_SYMBOL_GPL(hyperv_stop_tsc_emulation);
 168
 169 static inline bool hv_reenlightenment_available(void)
 170 {
 171         /*
 172          * Check for required features and privileges to make TSC frequency
 173          * change notifications work.
 174          */
 175         return ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
 176                 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE &&
 177                 ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT;
 178 }
 179
 180 DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_reenlightenment)
 181 {
 182         apic_eoi();
 183         inc_irq_stat(irq_hv_reenlightenment_count);
 184         schedule_delayed_work(&hv_reenlightenment_work, HZ/10);
 185 }
 186
 187 void set_hv_tscchange_cb(void (*cb)(void))
 188 {
 189         struct hv_reenlightenment_control re_ctrl = {
 190                 .vector = HYPERV_REENLIGHTENMENT_VECTOR,
 191                 .enabled = 1,
 192         };
 193         struct hv_tsc_emulation_control emu_ctrl = {.enabled = 1};
 194
 195         if (!hv_reenlightenment_available()) {
 196                 pr_warn("reenlightenment support is unavailable\n");
 197                 return;
 198         }
 199
 200         if (!hv_vp_index)
 201                 return;
 202
 203         hv_reenlightenment_cb = cb;
 204
 205         /* Make sure callback is registered before we write to MSRs */
 206         wmb();
 207
 208         re_ctrl.target_vp = hv_vp_index[get_cpu()];
 209
 210         wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
 211         wrmsrl(HV_X64_MSR_TSC_EMULATION_CONTROL, *((u64 *)&emu_ctrl));
 212
 213         put_cpu();
 214 }
 215 EXPORT_SYMBOL_GPL(set_hv_tscchange_cb);
 216
 217 void clear_hv_tscchange_cb(void)
 218 {
 219         struct hv_reenlightenment_control re_ctrl;
 220
 221         if (!hv_reenlightenment_available())
 222                 return;
 223
 224         rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
 225         re_ctrl.enabled = 0;
 226         wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
 227
 228         hv_reenlightenment_cb = NULL;
 229 }
 230 EXPORT_SYMBOL_GPL(clear_hv_tscchange_cb);
 231
 232 static int hv_cpu_die(unsigned int cpu)
 233 {
 234         struct hv_reenlightenment_control re_ctrl;
 235         unsigned int new_cpu;
 236         void **ghcb_va;
 237
 238         if (hv_ghcb_pg) {
 239                 ghcb_va = (void **)this_cpu_ptr(hv_ghcb_pg);
 240                 if (*ghcb_va)
 241                         iounmap(*ghcb_va);
 242                 *ghcb_va = NULL;
 243         }
 244
 245         hv_common_cpu_die(cpu);
 246
 247         if (hv_vp_assist_page && hv_vp_assist_page[cpu]) {
 248                 union hv_vp_assist_msr_contents msr = { 0 };
 249                 if (hv_root_partition) {
 250                         /*
 251                          * For root partition the VP assist page is mapped to
 252                          * hypervisor provided page, and thus we unmap the
 253                          * page here and nullify it, so that in future we have
 254                          * correct page address mapped in hv_cpu_init.
 255                          */
 256                         memunmap(hv_vp_assist_page[cpu]);
 257                         hv_vp_assist_page[cpu] = NULL;
 258                         rdmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
 259                         msr.enable = 0;
 260                 }
 261                 wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
 262         }
 263
 264         if (hv_reenlightenment_cb == NULL)
 265                 return 0;
 266
 267         rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
 268         if (re_ctrl.target_vp == hv_vp_index[cpu]) {
 269                 /*
 270                  * Reassign reenlightenment notifications to some other online
 271                  * CPU or just disable the feature if there are no online CPUs
 272                  * left (happens on hibernation).
 273                  */
 274                 new_cpu = cpumask_any_but(cpu_online_mask, cpu);
 275
 276                 if (new_cpu < nr_cpu_ids)
 277                         re_ctrl.target_vp = hv_vp_index[new_cpu];
 278                 else
 279                         re_ctrl.enabled = 0;
 280
 281                 wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
 282         }
 283
 284         return 0;
 285 }
 286
 287 static int __init hv_pci_init(void)
 288 {
 289         int gen2vm = efi_enabled(EFI_BOOT);
 290
 291         /*
 292          * For Generation-2 VM, we exit from pci_arch_init() by returning 0.
 293          * The purpose is to suppress the harmless warning:
 294          * "PCI: Fatal: No config space access function found"
 295          */
 296         if (gen2vm)
 297                 return 0;
 298
 299         /* For Generation-1 VM, we'll proceed in pci_arch_init().  */
 300         return 1;
 301 }
 302
 303 static int hv_suspend(void)
 304 {
 305         union hv_x64_msr_hypercall_contents hypercall_msr;
 306         int ret;
 307
 308         if (hv_root_partition)
 309                 return -EPERM;
 310
 311         /*
 312          * Reset the hypercall page as it is going to be invalidated
 313          * across hibernation. Setting hv_hypercall_pg to NULL ensures
 314          * that any subsequent hypercall operation fails safely instead of
 315          * crashing due to an access of an invalid page. The hypercall page
 316          * pointer is restored on resume.
 317          */
 318         hv_hypercall_pg_saved = hv_hypercall_pg;
 319         hv_hypercall_pg = NULL;
 320
 321         /* Disable the hypercall page in the hypervisor */
 322         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 323         hypercall_msr.enable = 0;
 324         wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 325
 326         ret = hv_cpu_die(0);
 327         return ret;
 328 }
 329
 330 static void hv_resume(void)
 331 {
 332         union hv_x64_msr_hypercall_contents hypercall_msr;
 333         int ret;
 334
 335         ret = hv_cpu_init(0);
 336         WARN_ON(ret);
 337
 338         /* Re-enable the hypercall page */
 339         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 340         hypercall_msr.enable = 1;
 341         hypercall_msr.guest_physical_address =
 342                 vmalloc_to_pfn(hv_hypercall_pg_saved);
 343         wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 344
 345         hv_hypercall_pg = hv_hypercall_pg_saved;
 346         hv_hypercall_pg_saved = NULL;
 347
 348         /*
 349          * Reenlightenment notifications are disabled by hv_cpu_die(0),
 350          * reenable them here if hv_reenlightenment_cb was previously set.
 351          */
 352         if (hv_reenlightenment_cb)
 353                 set_hv_tscchange_cb(hv_reenlightenment_cb);
 354 }
 355
 356 /* Note: when the ops are called, only CPU0 is online and IRQs are disabled. */
 357 static struct syscore_ops hv_syscore_ops = {
 358         .suspend        = hv_suspend,
 359         .resume         = hv_resume,
 360 };
 361
 362 static void (* __initdata old_setup_percpu_clockev)(void);
 363
 364 static void __init hv_stimer_setup_percpu_clockev(void)
 365 {
 366         /*
 367          * Ignore any errors in setting up stimer clockevents
 368          * as we can run with the LAPIC timer as a fallback.
 369          */
 370         (void)hv_stimer_alloc(false);
 371
 372         /*
 373          * Still register the LAPIC timer, because the direct-mode STIMER is
 374          * not supported by old versions of Hyper-V. This also allows users
 375          * to switch to LAPIC timer via /sys, if they want to.
 376          */
 377         if (old_setup_percpu_clockev)
 378                 old_setup_percpu_clockev();
 379 }
 380
 381 static void __init hv_get_partition_id(void)
 382 {
 383         struct hv_get_partition_id *output_page;
 384         u64 status;
 385         unsigned long flags;
 386
 387         local_irq_save(flags);
 388         output_page = *this_cpu_ptr(hyperv_pcpu_output_arg);
 389         status = hv_do_hypercall(HVCALL_GET_PARTITION_ID, NULL, output_page);
 390         if (!hv_result_success(status)) {
 391                 /* No point in proceeding if this failed */
 392                 pr_err("Failed to get partition ID: %lld\n", status);
 393                 BUG();
 394         }
 395         hv_current_partition_id = output_page->partition_id;
 396         local_irq_restore(flags);
 397 }
 398
 399 #if IS_ENABLED(CONFIG_HYPERV_VTL_MODE)
 400 static u8 __init get_vtl(void)
 401 {
 402         u64 control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_REGISTERS;
 403         struct hv_get_vp_registers_input *input;
 404         struct hv_get_vp_registers_output *output;
 405         unsigned long flags;
 406         u64 ret;
 407
 408         local_irq_save(flags);
 409         input = *this_cpu_ptr(hyperv_pcpu_input_arg);
 410         output = (struct hv_get_vp_registers_output *)input;
 411
 412         memset(input, 0, struct_size(input, element, 1));
 413         input->header.partitionid = HV_PARTITION_ID_SELF;
 414         input->header.vpindex = HV_VP_INDEX_SELF;
 415         input->header.inputvtl = 0;
 416         input->element[0].name0 = HV_X64_REGISTER_VSM_VP_STATUS;
 417
 418         ret = hv_do_hypercall(control, input, output);
 419         if (hv_result_success(ret)) {
 420                 ret = output->as64.low & HV_X64_VTL_MASK;
 421         } else {
 422                 pr_err("Failed to get VTL(error: %lld) exiting...\n", ret);
 423                 BUG();
 424         }
 425
 426         local_irq_restore(flags);
 427         return ret;
 428 }
 429 #else
 430 static inline u8 get_vtl(void) { return 0; }
 431 #endif
 432
 433 /*
 434  * This function is to be invoked early in the boot sequence after the
 435  * hypervisor has been detected.
 436  *
 437  * 1. Setup the hypercall page.
 438  * 2. Register Hyper-V specific clocksource.
 439  * 3. Setup Hyper-V specific APIC entry points.
 440  */
 441 void __init hyperv_init(void)
 442 {
 443         u64 guest_id;
 444         union hv_x64_msr_hypercall_contents hypercall_msr;
 445         int cpuhp;
 446
 447         if (x86_hyper_type != X86_HYPER_MS_HYPERV)
 448                 return;
 449
 450         if (hv_common_init())
 451                 return;
 452
 453         /*
 454          * The VP assist page is useless to a TDX guest: the only use we
 455          * would have for it is lazy EOI, which can not be used with TDX.
 456          */
 457         if (hv_isolation_type_tdx())
 458                 hv_vp_assist_page = NULL;
 459         else
 460                 hv_vp_assist_page = kcalloc(num_possible_cpus(),
 461                                             sizeof(*hv_vp_assist_page),
 462                                             GFP_KERNEL);
 463         if (!hv_vp_assist_page) {
 464                 ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
 465
 466                 if (!hv_isolation_type_tdx())
 467                         goto common_free;
 468         }
 469
 470         if (ms_hyperv.paravisor_present && hv_isolation_type_snp()) {
 471                 /* Negotiate GHCB Version. */
 472                 if (!hv_ghcb_negotiate_protocol())
 473                         hv_ghcb_terminate(SEV_TERM_SET_GEN,
 474                                           GHCB_SEV_ES_PROT_UNSUPPORTED);
 475
 476                 hv_ghcb_pg = alloc_percpu(union hv_ghcb *);
 477                 if (!hv_ghcb_pg)
 478                         goto free_vp_assist_page;
 479         }
 480
 481         cpuhp = cpuhp_setup_state(CPUHP_AP_HYPERV_ONLINE, "x86/hyperv_init:online",
 482                                   hv_cpu_init, hv_cpu_die);
 483         if (cpuhp < 0)
 484                 goto free_ghcb_page;
 485
 486         /*
 487          * Setup the hypercall page and enable hypercalls.
 488          * 1. Register the guest ID
 489          * 2. Enable the hypercall and register the hypercall page
 490          *
 491          * A TDX VM with no paravisor only uses TDX GHCI rather than hv_hypercall_pg:
 492          * when the hypercall input is a page, such a VM must pass a decrypted
 493          * page to Hyper-V, e.g. hv_post_message() uses the per-CPU page
 494          * hyperv_pcpu_input_arg, which is decrypted if no paravisor is present.
 495          *
 496          * A TDX VM with the paravisor uses hv_hypercall_pg for most hypercalls,
 497          * which are handled by the paravisor and the VM must use an encrypted
 498          * input page: in such a VM, the hyperv_pcpu_input_arg is encrypted and
 499          * used in the hypercalls, e.g. see hv_mark_gpa_visibility() and
 500          * hv_arch_irq_unmask(). Such a VM uses TDX GHCI for two hypercalls:
 501          * 1. HVCALL_SIGNAL_EVENT: see vmbus_set_event() and _hv_do_fast_hypercall8().
 502          * 2. HVCALL_POST_MESSAGE: the input page must be a decrypted page, i.e.
 503          * hv_post_message() in such a VM can't use the encrypted hyperv_pcpu_input_arg;
 504          * instead, hv_post_message() uses the post_msg_page, which is decrypted
 505          * in such a VM and is only used in such a VM.
 506          */
 507         guest_id = hv_generate_guest_id(LINUX_VERSION_CODE);
 508         wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
 509
 510         /* With the paravisor, the VM must also write the ID via GHCB/GHCI */
 511         hv_ivm_msr_write(HV_X64_MSR_GUEST_OS_ID, guest_id);
 512
 513         /* A TDX VM with no paravisor only uses TDX GHCI rather than hv_hypercall_pg */
 514         if (hv_isolation_type_tdx() && !ms_hyperv.paravisor_present)
 515                 goto skip_hypercall_pg_init;
 516
 517         hv_hypercall_pg = __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START,
 518                         VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_ROX,
 519                         VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
 520                         __builtin_return_address(0));
 521         if (hv_hypercall_pg == NULL)
 522                 goto clean_guest_os_id;
 523
 524         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 525         hypercall_msr.enable = 1;
 526
 527         if (hv_root_partition) {
 528                 struct page *pg;
 529                 void *src;
 530
 531                 /*
 532                  * For the root partition, the hypervisor will set up its
 533                  * hypercall page. The hypervisor guarantees it will not show
 534                  * up in the root's address space. The root can't change the
 535                  * location of the hypercall page.
 536                  *
 537                  * Order is important here. We must enable the hypercall page
 538                  * so it is populated with code, then copy the code to an
 539                  * executable page.
 540                  */
 541                 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 542
 543                 pg = vmalloc_to_page(hv_hypercall_pg);
 544                 src = memremap(hypercall_msr.guest_physical_address << PAGE_SHIFT, PAGE_SIZE,
 545                                 MEMREMAP_WB);
 546                 BUG_ON(!src);
 547                 memcpy_to_page(pg, 0, src, HV_HYP_PAGE_SIZE);
 548                 memunmap(src);
 549
 550                 hv_remap_tsc_clocksource();
 551         } else {
 552                 hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
 553                 wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 554         }
 555
 556 skip_hypercall_pg_init:
 557         /*
 558          * Some versions of Hyper-V that provide IBT in guest VMs have a bug
 559          * in that there's no ENDBR64 instruction at the entry to the
 560          * hypercall page. Because hypercalls are invoked via an indirect call
 561          * to the hypercall page, all hypercall attempts fail when IBT is
 562          * enabled, and Linux panics. For such buggy versions, disable IBT.
 563          *
 564          * Fixed versions of Hyper-V always provide ENDBR64 on the hypercall
 565          * page, so if future Linux kernel versions enable IBT for 32-bit
 566          * builds, additional hypercall page hackery will be required here
 567          * to provide an ENDBR32.
 568          */
 569 #ifdef CONFIG_X86_KERNEL_IBT
 570         if (cpu_feature_enabled(X86_FEATURE_IBT) &&
 571             *(u32 *)hv_hypercall_pg != gen_endbr()) {
 572                 setup_clear_cpu_cap(X86_FEATURE_IBT);
 573                 pr_warn("Disabling IBT because of Hyper-V bug\n");
 574         }
 575 #endif
 576
 577         /*
 578          * hyperv_init() is called before LAPIC is initialized: see
 579          * apic_intr_mode_init() -> x86_platform.apic_post_init() and
 580          * apic_bsp_setup() -> setup_local_APIC(). The direct-mode STIMER
 581          * depends on LAPIC, so hv_stimer_alloc() should be called from
 582          * x86_init.timers.setup_percpu_clockev.
 583          */
 584         old_setup_percpu_clockev = x86_init.timers.setup_percpu_clockev;
 585         x86_init.timers.setup_percpu_clockev = hv_stimer_setup_percpu_clockev;
 586
 587         hv_apic_init();
 588
 589         x86_init.pci.arch_init = hv_pci_init;
 590
 591         register_syscore_ops(&hv_syscore_ops);
 592
 593         hyperv_init_cpuhp = cpuhp;
 594
 595         if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_ACCESS_PARTITION_ID)
 596                 hv_get_partition_id();
 597
 598         BUG_ON(hv_root_partition && hv_current_partition_id == ~0ull);
 599
 600 #ifdef CONFIG_PCI_MSI
 601         /*
 602          * If we're running as root, we want to create our own PCI MSI domain.
 603          * We can't set this in hv_pci_init because that would be too late.
 604          */
 605         if (hv_root_partition)
 606                 x86_init.irqs.create_pci_msi_domain = hv_create_pci_msi_domain;
 607 #endif
 608
 609         /* Query the VMs extended capability once, so that it can be cached. */
 610         hv_query_ext_cap(0);
 611
 612         /* Find the VTL */
 613         ms_hyperv.vtl = get_vtl();
 614
 615         if (ms_hyperv.vtl > 0) /* non default VTL */
 616                 hv_vtl_early_init();
 617
 618         return;
 619
 620 clean_guest_os_id:
 621         wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
 622         hv_ivm_msr_write(HV_X64_MSR_GUEST_OS_ID, 0);
 623         cpuhp_remove_state(cpuhp);
 624 free_ghcb_page:
 625         free_percpu(hv_ghcb_pg);
 626 free_vp_assist_page:
 627         kfree(hv_vp_assist_page);
 628         hv_vp_assist_page = NULL;
 629 common_free:
 630         hv_common_free();
 631 }
 632
 633 /*
 634  * This routine is called before kexec/kdump, it does the required cleanup.
 635  */
 636 void hyperv_cleanup(void)
 637 {
 638         union hv_x64_msr_hypercall_contents hypercall_msr;
 639         union hv_reference_tsc_msr tsc_msr;
 640
 641         /* Reset our OS id */
 642         wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
 643         hv_ivm_msr_write(HV_X64_MSR_GUEST_OS_ID, 0);
 644
 645         /*
 646          * Reset hypercall page reference before reset the page,
 647          * let hypercall operations fail safely rather than
 648          * panic the kernel for using invalid hypercall page
 649          */
 650         hv_hypercall_pg = NULL;
 651
 652         /* Reset the hypercall page */
 653         hypercall_msr.as_uint64 = hv_get_register(HV_X64_MSR_HYPERCALL);
 654         hypercall_msr.enable = 0;
 655         hv_set_register(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 656
 657         /* Reset the TSC page */
 658         tsc_msr.as_uint64 = hv_get_register(HV_X64_MSR_REFERENCE_TSC);
 659         tsc_msr.enable = 0;
 660         hv_set_register(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
 661 }
 662
 663 void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die)
 664 {
 665         static bool panic_reported;
 666         u64 guest_id;
 667
 668         if (in_die && !panic_on_oops)
 669                 return;
 670
 671         /*
 672          * We prefer to report panic on 'die' chain as we have proper
 673          * registers to report, but if we miss it (e.g. on BUG()) we need
 674          * to report it on 'panic'.
 675          */
 676         if (panic_reported)
 677                 return;
 678         panic_reported = true;
 679
 680         rdmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
 681
 682         wrmsrl(HV_X64_MSR_CRASH_P0, err);
 683         wrmsrl(HV_X64_MSR_CRASH_P1, guest_id);
 684         wrmsrl(HV_X64_MSR_CRASH_P2, regs->ip);
 685         wrmsrl(HV_X64_MSR_CRASH_P3, regs->ax);
 686         wrmsrl(HV_X64_MSR_CRASH_P4, regs->sp);
 687
 688         /*
 689          * Let Hyper-V know there is crash data available
 690          */
 691         wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
 692 }
 693 EXPORT_SYMBOL_GPL(hyperv_report_panic);
 694
 695 bool hv_is_hyperv_initialized(void)
 696 {
 697         union hv_x64_msr_hypercall_contents hypercall_msr;
 698
 699         /*
 700          * Ensure that we're really on Hyper-V, and not a KVM or Xen
 701          * emulation of Hyper-V
 702          */
 703         if (x86_hyper_type != X86_HYPER_MS_HYPERV)
 704                 return false;
 705
 706         /* A TDX VM with no paravisor uses TDX GHCI call rather than hv_hypercall_pg */
 707         if (hv_isolation_type_tdx() && !ms_hyperv.paravisor_present)
 708                 return true;
 709         /*
 710          * Verify that earlier initialization succeeded by checking
 711          * that the hypercall page is setup
 712          */
 713         hypercall_msr.as_uint64 = 0;
 714         rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 715
 716         return hypercall_msr.enable;
 717 }
 718 EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);