arch/x86/kernel/kvm.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * KVM paravirt_ops implementation
   4  *
   5  * Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
   6  * Copyright IBM Corporation, 2007
   7  *   Authors: Anthony Liguori <aliguori@us.ibm.com>
   8  */
   9
  10 #define pr_fmt(fmt) "kvm-guest: " fmt
  11
  12 #include <linux/context_tracking.h>
  13 #include <linux/init.h>
  14 #include <linux/irq.h>
  15 #include <linux/kernel.h>
  16 #include <linux/kvm_para.h>
  17 #include <linux/cpu.h>
  18 #include <linux/mm.h>
  19 #include <linux/highmem.h>
  20 #include <linux/hardirq.h>
  21 #include <linux/notifier.h>
  22 #include <linux/reboot.h>
  23 #include <linux/hash.h>
  24 #include <linux/sched.h>
  25 #include <linux/slab.h>
  26 #include <linux/kprobes.h>
  27 #include <linux/nmi.h>
  28 #include <linux/swait.h>
  29 #include <linux/syscore_ops.h>
  30 #include <linux/cc_platform.h>
  31 #include <linux/efi.h>
  32 #include <asm/timer.h>
  33 #include <asm/cpu.h>
  34 #include <asm/traps.h>
  35 #include <asm/desc.h>
  36 #include <asm/tlbflush.h>
  37 #include <asm/apic.h>
  38 #include <asm/apicdef.h>
  39 #include <asm/hypervisor.h>
  40 #include <asm/tlb.h>
  41 #include <asm/cpuidle_haltpoll.h>
  42 #include <asm/ptrace.h>
  43 #include <asm/reboot.h>
  44 #include <asm/svm.h>
  45 #include <asm/e820/api.h>
  46
  47 DEFINE_STATIC_KEY_FALSE(kvm_async_pf_enabled);
  48
  49 static int kvmapf = 1;
  50
  51 static int __init parse_no_kvmapf(char *arg)
  52 {
  53         kvmapf = 0;
  54         return 0;
  55 }
  56
  57 early_param("no-kvmapf", parse_no_kvmapf);
  58
  59 static int steal_acc = 1;
  60 static int __init parse_no_stealacc(char *arg)
  61 {
  62         steal_acc = 0;
  63         return 0;
  64 }
  65
  66 early_param("no-steal-acc", parse_no_stealacc);
  67
  68 static DEFINE_PER_CPU_DECRYPTED(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);
  69 DEFINE_PER_CPU_DECRYPTED(struct kvm_steal_time, steal_time) __aligned(64) __visible;
  70 static int has_steal_clock = 0;
  71
  72 /*
  73  * No need for any "IO delay" on KVM
  74  */
  75 static void kvm_io_delay(void)
  76 {
  77 }
  78
  79 #define KVM_TASK_SLEEP_HASHBITS 8
  80 #define KVM_TASK_SLEEP_HASHSIZE (1<<KVM_TASK_SLEEP_HASHBITS)
  81
  82 struct kvm_task_sleep_node {
  83         struct hlist_node link;
  84         struct swait_queue_head wq;
  85         u32 token;
  86         int cpu;
  87 };
  88
  89 static struct kvm_task_sleep_head {
  90         raw_spinlock_t lock;
  91         struct hlist_head list;
  92 } async_pf_sleepers[KVM_TASK_SLEEP_HASHSIZE];
  93
  94 static struct kvm_task_sleep_node *_find_apf_task(struct kvm_task_sleep_head *b,
  95                                                   u32 token)
  96 {
  97         struct hlist_node *p;
  98
  99         hlist_for_each(p, &b->list) {
 100                 struct kvm_task_sleep_node *n =
 101                         hlist_entry(p, typeof(*n), link);
 102                 if (n->token == token)
 103                         return n;
 104         }
 105
 106         return NULL;
 107 }
 108
 109 static bool kvm_async_pf_queue_task(u32 token, struct kvm_task_sleep_node *n)
 110 {
 111         u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
 112         struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
 113         struct kvm_task_sleep_node *e;
 114
 115         raw_spin_lock(&b->lock);
 116         e = _find_apf_task(b, token);
 117         if (e) {
 118                 /* dummy entry exist -> wake up was delivered ahead of PF */
 119                 hlist_del(&e->link);
 120                 raw_spin_unlock(&b->lock);
 121                 kfree(e);
 122                 return false;
 123         }
 124
 125         n->token = token;
 126         n->cpu = smp_processor_id();
 127         init_swait_queue_head(&n->wq);
 128         hlist_add_head(&n->link, &b->list);
 129         raw_spin_unlock(&b->lock);
 130         return true;
 131 }
 132
 133 /*
 134  * kvm_async_pf_task_wait_schedule - Wait for pagefault to be handled
 135  * @token:      Token to identify the sleep node entry
 136  *
 137  * Invoked from the async pagefault handling code or from the VM exit page
 138  * fault handler. In both cases RCU is watching.
 139  */
 140 void kvm_async_pf_task_wait_schedule(u32 token)
 141 {
 142         struct kvm_task_sleep_node n;
 143         DECLARE_SWAITQUEUE(wait);
 144
 145         lockdep_assert_irqs_disabled();
 146
 147         if (!kvm_async_pf_queue_task(token, &n))
 148                 return;
 149
 150         for (;;) {
 151                 prepare_to_swait_exclusive(&n.wq, &wait, TASK_UNINTERRUPTIBLE);
 152                 if (hlist_unhashed(&n.link))
 153                         break;
 154
 155                 local_irq_enable();
 156                 schedule();
 157                 local_irq_disable();
 158         }
 159         finish_swait(&n.wq, &wait);
 160 }
 161 EXPORT_SYMBOL_GPL(kvm_async_pf_task_wait_schedule);
 162
 163 static void apf_task_wake_one(struct kvm_task_sleep_node *n)
 164 {
 165         hlist_del_init(&n->link);
 166         if (swq_has_sleeper(&n->wq))
 167                 swake_up_one(&n->wq);
 168 }
 169
 170 static void apf_task_wake_all(void)
 171 {
 172         int i;
 173
 174         for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) {
 175                 struct kvm_task_sleep_head *b = &async_pf_sleepers[i];
 176                 struct kvm_task_sleep_node *n;
 177                 struct hlist_node *p, *next;
 178
 179                 raw_spin_lock(&b->lock);
 180                 hlist_for_each_safe(p, next, &b->list) {
 181                         n = hlist_entry(p, typeof(*n), link);
 182                         if (n->cpu == smp_processor_id())
 183                                 apf_task_wake_one(n);
 184                 }
 185                 raw_spin_unlock(&b->lock);
 186         }
 187 }
 188
 189 void kvm_async_pf_task_wake(u32 token)
 190 {
 191         u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
 192         struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
 193         struct kvm_task_sleep_node *n;
 194
 195         if (token == ~0) {
 196                 apf_task_wake_all();
 197                 return;
 198         }
 199
 200 again:
 201         raw_spin_lock(&b->lock);
 202         n = _find_apf_task(b, token);
 203         if (!n) {
 204                 /*
 205                  * async PF was not yet handled.
 206                  * Add dummy entry for the token.
 207                  */
 208                 n = kzalloc(sizeof(*n), GFP_ATOMIC);
 209                 if (!n) {
 210                         /*
 211                          * Allocation failed! Busy wait while other cpu
 212                          * handles async PF.
 213                          */
 214                         raw_spin_unlock(&b->lock);
 215                         cpu_relax();
 216                         goto again;
 217                 }
 218                 n->token = token;
 219                 n->cpu = smp_processor_id();
 220                 init_swait_queue_head(&n->wq);
 221                 hlist_add_head(&n->link, &b->list);
 222         } else {
 223                 apf_task_wake_one(n);
 224         }
 225         raw_spin_unlock(&b->lock);
 226         return;
 227 }
 228 EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake);
 229
 230 noinstr u32 kvm_read_and_reset_apf_flags(void)
 231 {
 232         u32 flags = 0;
 233
 234         if (__this_cpu_read(apf_reason.enabled)) {
 235                 flags = __this_cpu_read(apf_reason.flags);
 236                 __this_cpu_write(apf_reason.flags, 0);
 237         }
 238
 239         return flags;
 240 }
 241 EXPORT_SYMBOL_GPL(kvm_read_and_reset_apf_flags);
 242
 243 noinstr bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token)
 244 {
 245         u32 flags = kvm_read_and_reset_apf_flags();
 246         irqentry_state_t state;
 247
 248         if (!flags)
 249                 return false;
 250
 251         state = irqentry_enter(regs);
 252         instrumentation_begin();
 253
 254         /*
 255          * If the host managed to inject an async #PF into an interrupt
 256          * disabled region, then die hard as this is not going to end well
 257          * and the host side is seriously broken.
 258          */
 259         if (unlikely(!(regs->flags & X86_EFLAGS_IF)))
 260                 panic("Host injected async #PF in interrupt disabled region\n");
 261
 262         if (flags & KVM_PV_REASON_PAGE_NOT_PRESENT) {
 263                 if (unlikely(!(user_mode(regs))))
 264                         panic("Host injected async #PF in kernel mode\n");
 265                 /* Page is swapped out by the host. */
 266                 kvm_async_pf_task_wait_schedule(token);
 267         } else {
 268                 WARN_ONCE(1, "Unexpected async PF flags: %x\n", flags);
 269         }
 270
 271         instrumentation_end();
 272         irqentry_exit(regs, state);
 273         return true;
 274 }
 275
 276 DEFINE_IDTENTRY_SYSVEC(sysvec_kvm_asyncpf_interrupt)
 277 {
 278         struct pt_regs *old_regs = set_irq_regs(regs);
 279         u32 token;
 280
 281         ack_APIC_irq();
 282
 283         inc_irq_stat(irq_hv_callback_count);
 284
 285         if (__this_cpu_read(apf_reason.enabled)) {
 286                 token = __this_cpu_read(apf_reason.token);
 287                 kvm_async_pf_task_wake(token);
 288                 __this_cpu_write(apf_reason.token, 0);
 289                 wrmsrl(MSR_KVM_ASYNC_PF_ACK, 1);
 290         }
 291
 292         set_irq_regs(old_regs);
 293 }
 294
 295 static void __init paravirt_ops_setup(void)
 296 {
 297         pv_info.name = "KVM";
 298
 299         if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
 300                 pv_ops.cpu.io_delay = kvm_io_delay;
 301
 302 #ifdef CONFIG_X86_IO_APIC
 303         no_timer_check = 1;
 304 #endif
 305 }
 306
 307 static void kvm_register_steal_time(void)
 308 {
 309         int cpu = smp_processor_id();
 310         struct kvm_steal_time *st = &per_cpu(steal_time, cpu);
 311
 312         if (!has_steal_clock)
 313                 return;
 314
 315         wrmsrl(MSR_KVM_STEAL_TIME, (slow_virt_to_phys(st) | KVM_MSR_ENABLED));
 316         pr_debug("stealtime: cpu %d, msr %llx\n", cpu,
 317                 (unsigned long long) slow_virt_to_phys(st));
 318 }
 319
 320 static DEFINE_PER_CPU_DECRYPTED(unsigned long, kvm_apic_eoi) = KVM_PV_EOI_DISABLED;
 321
 322 static notrace void kvm_guest_apic_eoi_write(u32 reg, u32 val)
 323 {
 324         /**
 325          * This relies on __test_and_clear_bit to modify the memory
 326          * in a way that is atomic with respect to the local CPU.
 327          * The hypervisor only accesses this memory from the local CPU so
 328          * there's no need for lock or memory barriers.
 329          * An optimization barrier is implied in apic write.
 330          */
 331         if (__test_and_clear_bit(KVM_PV_EOI_BIT, this_cpu_ptr(&kvm_apic_eoi)))
 332                 return;
 333         apic->native_eoi_write(APIC_EOI, APIC_EOI_ACK);
 334 }
 335
 336 static void kvm_guest_cpu_init(void)
 337 {
 338         if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_INT) && kvmapf) {
 339                 u64 pa = slow_virt_to_phys(this_cpu_ptr(&apf_reason));
 340
 341                 WARN_ON_ONCE(!static_branch_likely(&kvm_async_pf_enabled));
 342
 343                 pa = slow_virt_to_phys(this_cpu_ptr(&apf_reason));
 344                 pa |= KVM_ASYNC_PF_ENABLED | KVM_ASYNC_PF_DELIVERY_AS_INT;
 345
 346                 if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_VMEXIT))
 347                         pa |= KVM_ASYNC_PF_DELIVERY_AS_PF_VMEXIT;
 348
 349                 wrmsrl(MSR_KVM_ASYNC_PF_INT, HYPERVISOR_CALLBACK_VECTOR);
 350
 351                 wrmsrl(MSR_KVM_ASYNC_PF_EN, pa);
 352                 __this_cpu_write(apf_reason.enabled, 1);
 353                 pr_debug("setup async PF for cpu %d\n", smp_processor_id());
 354         }
 355
 356         if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) {
 357                 unsigned long pa;
 358
 359                 /* Size alignment is implied but just to make it explicit. */
 360                 BUILD_BUG_ON(__alignof__(kvm_apic_eoi) < 4);
 361                 __this_cpu_write(kvm_apic_eoi, 0);
 362                 pa = slow_virt_to_phys(this_cpu_ptr(&kvm_apic_eoi))
 363                         | KVM_MSR_ENABLED;
 364                 wrmsrl(MSR_KVM_PV_EOI_EN, pa);
 365         }
 366
 367         if (has_steal_clock)
 368                 kvm_register_steal_time();
 369 }
 370
 371 static void kvm_pv_disable_apf(void)
 372 {
 373         if (!__this_cpu_read(apf_reason.enabled))
 374                 return;
 375
 376         wrmsrl(MSR_KVM_ASYNC_PF_EN, 0);
 377         __this_cpu_write(apf_reason.enabled, 0);
 378
 379         pr_debug("disable async PF for cpu %d\n", smp_processor_id());
 380 }
 381
 382 static void kvm_disable_steal_time(void)
 383 {
 384         if (!has_steal_clock)
 385                 return;
 386
 387         wrmsr(MSR_KVM_STEAL_TIME, 0, 0);
 388 }
 389
 390 static u64 kvm_steal_clock(int cpu)
 391 {
 392         u64 steal;
 393         struct kvm_steal_time *src;
 394         int version;
 395
 396         src = &per_cpu(steal_time, cpu);
 397         do {
 398                 version = src->version;
 399                 virt_rmb();
 400                 steal = src->steal;
 401                 virt_rmb();
 402         } while ((version & 1) || (version != src->version));
 403
 404         return steal;
 405 }
 406
 407 static inline void __set_percpu_decrypted(void *ptr, unsigned long size)
 408 {
 409         early_set_memory_decrypted((unsigned long) ptr, size);
 410 }
 411
 412 /*
 413  * Iterate through all possible CPUs and map the memory region pointed
 414  * by apf_reason, steal_time and kvm_apic_eoi as decrypted at once.
 415  *
 416  * Note: we iterate through all possible CPUs to ensure that CPUs
 417  * hotplugged will have their per-cpu variable already mapped as
 418  * decrypted.
 419  */
 420 static void __init sev_map_percpu_data(void)
 421 {
 422         int cpu;
 423
 424         if (!cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
 425                 return;
 426
 427         for_each_possible_cpu(cpu) {
 428                 __set_percpu_decrypted(&per_cpu(apf_reason, cpu), sizeof(apf_reason));
 429                 __set_percpu_decrypted(&per_cpu(steal_time, cpu), sizeof(steal_time));
 430                 __set_percpu_decrypted(&per_cpu(kvm_apic_eoi, cpu), sizeof(kvm_apic_eoi));
 431         }
 432 }
 433
 434 static void kvm_guest_cpu_offline(bool shutdown)
 435 {
 436         kvm_disable_steal_time();
 437         if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
 438                 wrmsrl(MSR_KVM_PV_EOI_EN, 0);
 439         if (kvm_para_has_feature(KVM_FEATURE_MIGRATION_CONTROL))
 440                 wrmsrl(MSR_KVM_MIGRATION_CONTROL, 0);
 441         kvm_pv_disable_apf();
 442         if (!shutdown)
 443                 apf_task_wake_all();
 444         kvmclock_disable();
 445 }
 446
 447 static int kvm_cpu_online(unsigned int cpu)
 448 {
 449         unsigned long flags;
 450
 451         local_irq_save(flags);
 452         kvm_guest_cpu_init();
 453         local_irq_restore(flags);
 454         return 0;
 455 }
 456
 457 #ifdef CONFIG_SMP
 458
 459 static DEFINE_PER_CPU(cpumask_var_t, __pv_cpu_mask);
 460
 461 static bool pv_tlb_flush_supported(void)
 462 {
 463         return (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
 464                 !kvm_para_has_hint(KVM_HINTS_REALTIME) &&
 465                 kvm_para_has_feature(KVM_FEATURE_STEAL_TIME) &&
 466                 (num_possible_cpus() != 1));
 467 }
 468
 469 static bool pv_ipi_supported(void)
 470 {
 471         return (kvm_para_has_feature(KVM_FEATURE_PV_SEND_IPI) &&
 472                (num_possible_cpus() != 1));
 473 }
 474
 475 static bool pv_sched_yield_supported(void)
 476 {
 477         return (kvm_para_has_feature(KVM_FEATURE_PV_SCHED_YIELD) &&
 478                 !kvm_para_has_hint(KVM_HINTS_REALTIME) &&
 479             kvm_para_has_feature(KVM_FEATURE_STEAL_TIME) &&
 480             (num_possible_cpus() != 1));
 481 }
 482
 483 #define KVM_IPI_CLUSTER_SIZE    (2 * BITS_PER_LONG)
 484
 485 static void __send_ipi_mask(const struct cpumask *mask, int vector)
 486 {
 487         unsigned long flags;
 488         int cpu, apic_id, icr;
 489         int min = 0, max = 0;
 490 #ifdef CONFIG_X86_64
 491         __uint128_t ipi_bitmap = 0;
 492 #else
 493         u64 ipi_bitmap = 0;
 494 #endif
 495         long ret;
 496
 497         if (cpumask_empty(mask))
 498                 return;
 499
 500         local_irq_save(flags);
 501
 502         switch (vector) {
 503         default:
 504                 icr = APIC_DM_FIXED | vector;
 505                 break;
 506         case NMI_VECTOR:
 507                 icr = APIC_DM_NMI;
 508                 break;
 509         }
 510
 511         for_each_cpu(cpu, mask) {
 512                 apic_id = per_cpu(x86_cpu_to_apicid, cpu);
 513                 if (!ipi_bitmap) {
 514                         min = max = apic_id;
 515                 } else if (apic_id < min && max - apic_id < KVM_IPI_CLUSTER_SIZE) {
 516                         ipi_bitmap <<= min - apic_id;
 517                         min = apic_id;
 518                 } else if (apic_id < min + KVM_IPI_CLUSTER_SIZE) {
 519                         max = apic_id < max ? max : apic_id;
 520                 } else {
 521                         ret = kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
 522                                 (unsigned long)(ipi_bitmap >> BITS_PER_LONG), min, icr);
 523                         WARN_ONCE(ret < 0, "kvm-guest: failed to send PV IPI: %ld",
 524                                   ret);
 525                         min = max = apic_id;
 526                         ipi_bitmap = 0;
 527                 }
 528                 __set_bit(apic_id - min, (unsigned long *)&ipi_bitmap);
 529         }
 530
 531         if (ipi_bitmap) {
 532                 ret = kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
 533                         (unsigned long)(ipi_bitmap >> BITS_PER_LONG), min, icr);
 534                 WARN_ONCE(ret < 0, "kvm-guest: failed to send PV IPI: %ld",
 535                           ret);
 536         }
 537
 538         local_irq_restore(flags);
 539 }
 540
 541 static void kvm_send_ipi_mask(const struct cpumask *mask, int vector)
 542 {
 543         __send_ipi_mask(mask, vector);
 544 }
 545
 546 static void kvm_send_ipi_mask_allbutself(const struct cpumask *mask, int vector)
 547 {
 548         unsigned int this_cpu = smp_processor_id();
 549         struct cpumask *new_mask = this_cpu_cpumask_var_ptr(__pv_cpu_mask);
 550         const struct cpumask *local_mask;
 551
 552         cpumask_copy(new_mask, mask);
 553         cpumask_clear_cpu(this_cpu, new_mask);
 554         local_mask = new_mask;
 555         __send_ipi_mask(local_mask, vector);
 556 }
 557
 558 static int __init setup_efi_kvm_sev_migration(void)
 559 {
 560         efi_char16_t efi_sev_live_migration_enabled[] = L"SevLiveMigrationEnabled";
 561         efi_guid_t efi_variable_guid = AMD_SEV_MEM_ENCRYPT_GUID;
 562         efi_status_t status;
 563         unsigned long size;
 564         bool enabled;
 565
 566         if (!cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT) ||
 567             !kvm_para_has_feature(KVM_FEATURE_MIGRATION_CONTROL))
 568                 return 0;
 569
 570         if (!efi_enabled(EFI_BOOT))
 571                 return 0;
 572
 573         if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
 574                 pr_info("%s : EFI runtime services are not enabled\n", __func__);
 575                 return 0;
 576         }
 577
 578         size = sizeof(enabled);
 579
 580         /* Get variable contents into buffer */
 581         status = efi.get_variable(efi_sev_live_migration_enabled,
 582                                   &efi_variable_guid, NULL, &size, &enabled);
 583
 584         if (status == EFI_NOT_FOUND) {
 585                 pr_info("%s : EFI live migration variable not found\n", __func__);
 586                 return 0;
 587         }
 588
 589         if (status != EFI_SUCCESS) {
 590                 pr_info("%s : EFI variable retrieval failed\n", __func__);
 591                 return 0;
 592         }
 593
 594         if (enabled == 0) {
 595                 pr_info("%s: live migration disabled in EFI\n", __func__);
 596                 return 0;
 597         }
 598
 599         pr_info("%s : live migration enabled in EFI\n", __func__);
 600         wrmsrl(MSR_KVM_MIGRATION_CONTROL, KVM_MIGRATION_READY);
 601
 602         return 1;
 603 }
 604
 605 late_initcall(setup_efi_kvm_sev_migration);
 606
 607 /*
 608  * Set the IPI entry points
 609  */
 610 static void kvm_setup_pv_ipi(void)
 611 {
 612         apic->send_IPI_mask = kvm_send_ipi_mask;
 613         apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
 614         pr_info("setup PV IPIs\n");
 615 }
 616
 617 static void kvm_smp_send_call_func_ipi(const struct cpumask *mask)
 618 {
 619         int cpu;
 620
 621         native_send_call_func_ipi(mask);
 622
 623         /* Make sure other vCPUs get a chance to run if they need to. */
 624         for_each_cpu(cpu, mask) {
 625                 if (vcpu_is_preempted(cpu)) {
 626                         kvm_hypercall1(KVM_HC_SCHED_YIELD, per_cpu(x86_cpu_to_apicid, cpu));
 627                         break;
 628                 }
 629         }
 630 }
 631
 632 static void kvm_flush_tlb_multi(const struct cpumask *cpumask,
 633                         const struct flush_tlb_info *info)
 634 {
 635         u8 state;
 636         int cpu;
 637         struct kvm_steal_time *src;
 638         struct cpumask *flushmask = this_cpu_cpumask_var_ptr(__pv_cpu_mask);
 639
 640         cpumask_copy(flushmask, cpumask);
 641         /*
 642          * We have to call flush only on online vCPUs. And
 643          * queue flush_on_enter for pre-empted vCPUs
 644          */
 645         for_each_cpu(cpu, flushmask) {
 646                 /*
 647                  * The local vCPU is never preempted, so we do not explicitly
 648                  * skip check for local vCPU - it will never be cleared from
 649                  * flushmask.
 650                  */
 651                 src = &per_cpu(steal_time, cpu);
 652                 state = READ_ONCE(src->preempted);
 653                 if ((state & KVM_VCPU_PREEMPTED)) {
 654                         if (try_cmpxchg(&src->preempted, &state,
 655                                         state | KVM_VCPU_FLUSH_TLB))
 656                                 __cpumask_clear_cpu(cpu, flushmask);
 657                 }
 658         }
 659
 660         native_flush_tlb_multi(flushmask, info);
 661 }
 662
 663 static __init int kvm_alloc_cpumask(void)
 664 {
 665         int cpu;
 666
 667         if (!kvm_para_available() || nopv)
 668                 return 0;
 669
 670         if (pv_tlb_flush_supported() || pv_ipi_supported())
 671                 for_each_possible_cpu(cpu) {
 672                         zalloc_cpumask_var_node(per_cpu_ptr(&__pv_cpu_mask, cpu),
 673                                 GFP_KERNEL, cpu_to_node(cpu));
 674                 }
 675
 676         return 0;
 677 }
 678 arch_initcall(kvm_alloc_cpumask);
 679
 680 static void __init kvm_smp_prepare_boot_cpu(void)
 681 {
 682         /*
 683          * Map the per-cpu variables as decrypted before kvm_guest_cpu_init()
 684          * shares the guest physical address with the hypervisor.
 685          */
 686         sev_map_percpu_data();
 687
 688         kvm_guest_cpu_init();
 689         native_smp_prepare_boot_cpu();
 690         kvm_spinlock_init();
 691 }
 692
 693 static int kvm_cpu_down_prepare(unsigned int cpu)
 694 {
 695         unsigned long flags;
 696
 697         local_irq_save(flags);
 698         kvm_guest_cpu_offline(false);
 699         local_irq_restore(flags);
 700         return 0;
 701 }
 702
 703 #endif
 704
 705 static int kvm_suspend(void)
 706 {
 707         kvm_guest_cpu_offline(false);
 708
 709         return 0;
 710 }
 711
 712 static void kvm_resume(void)
 713 {
 714         kvm_cpu_online(raw_smp_processor_id());
 715 }
 716
 717 static struct syscore_ops kvm_syscore_ops = {
 718         .suspend        = kvm_suspend,
 719         .resume         = kvm_resume,
 720 };
 721
 722 static void kvm_pv_guest_cpu_reboot(void *unused)
 723 {
 724         kvm_guest_cpu_offline(true);
 725 }
 726
 727 static int kvm_pv_reboot_notify(struct notifier_block *nb,
 728                                 unsigned long code, void *unused)
 729 {
 730         if (code == SYS_RESTART)
 731                 on_each_cpu(kvm_pv_guest_cpu_reboot, NULL, 1);
 732         return NOTIFY_DONE;
 733 }
 734
 735 static struct notifier_block kvm_pv_reboot_nb = {
 736         .notifier_call = kvm_pv_reboot_notify,
 737 };
 738
 739 /*
 740  * After a PV feature is registered, the host will keep writing to the
 741  * registered memory location. If the guest happens to shutdown, this memory
 742  * won't be valid. In cases like kexec, in which you install a new kernel, this
 743  * means a random memory location will be kept being written.
 744  */
 745 #ifdef CONFIG_KEXEC_CORE
 746 static void kvm_crash_shutdown(struct pt_regs *regs)
 747 {
 748         kvm_guest_cpu_offline(true);
 749         native_machine_crash_shutdown(regs);
 750 }
 751 #endif
 752
 753 static void __init kvm_guest_init(void)
 754 {
 755         int i;
 756
 757         paravirt_ops_setup();
 758         register_reboot_notifier(&kvm_pv_reboot_nb);
 759         for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++)
 760                 raw_spin_lock_init(&async_pf_sleepers[i].lock);
 761
 762         if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
 763                 has_steal_clock = 1;
 764                 static_call_update(pv_steal_clock, kvm_steal_clock);
 765         }
 766
 767         if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
 768                 apic_set_eoi_write(kvm_guest_apic_eoi_write);
 769
 770         if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_INT) && kvmapf) {
 771                 static_branch_enable(&kvm_async_pf_enabled);
 772                 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_kvm_asyncpf_interrupt);
 773         }
 774
 775 #ifdef CONFIG_SMP
 776         if (pv_tlb_flush_supported()) {
 777                 pv_ops.mmu.flush_tlb_multi = kvm_flush_tlb_multi;
 778                 pv_ops.mmu.tlb_remove_table = tlb_remove_table;
 779                 pr_info("KVM setup pv remote TLB flush\n");
 780         }
 781
 782         smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
 783         if (pv_sched_yield_supported()) {
 784                 smp_ops.send_call_func_ipi = kvm_smp_send_call_func_ipi;
 785                 pr_info("setup PV sched yield\n");
 786         }
 787         if (cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/kvm:online",
 788                                       kvm_cpu_online, kvm_cpu_down_prepare) < 0)
 789                 pr_err("failed to install cpu hotplug callbacks\n");
 790 #else
 791         sev_map_percpu_data();
 792         kvm_guest_cpu_init();
 793 #endif
 794
 795 #ifdef CONFIG_KEXEC_CORE
 796         machine_ops.crash_shutdown = kvm_crash_shutdown;
 797 #endif
 798
 799         register_syscore_ops(&kvm_syscore_ops);
 800
 801         /*
 802          * Hard lockup detection is enabled by default. Disable it, as guests
 803          * can get false positives too easily, for example if the host is
 804          * overcommitted.
 805          */
 806         hardlockup_detector_disable();
 807 }
 808
 809 static noinline uint32_t __kvm_cpuid_base(void)
 810 {
 811         if (boot_cpu_data.cpuid_level < 0)
 812                 return 0;       /* So we don't blow up on old processors */
 813
 814         if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
 815                 return hypervisor_cpuid_base(KVM_SIGNATURE, 0);
 816
 817         return 0;
 818 }
 819
 820 static inline uint32_t kvm_cpuid_base(void)
 821 {
 822         static int kvm_cpuid_base = -1;
 823
 824         if (kvm_cpuid_base == -1)
 825                 kvm_cpuid_base = __kvm_cpuid_base();
 826
 827         return kvm_cpuid_base;
 828 }
 829
 830 bool kvm_para_available(void)
 831 {
 832         return kvm_cpuid_base() != 0;
 833 }
 834 EXPORT_SYMBOL_GPL(kvm_para_available);
 835
 836 unsigned int kvm_arch_para_features(void)
 837 {
 838         return cpuid_eax(kvm_cpuid_base() | KVM_CPUID_FEATURES);
 839 }
 840
 841 unsigned int kvm_arch_para_hints(void)
 842 {
 843         return cpuid_edx(kvm_cpuid_base() | KVM_CPUID_FEATURES);
 844 }
 845 EXPORT_SYMBOL_GPL(kvm_arch_para_hints);
 846
 847 static uint32_t __init kvm_detect(void)
 848 {
 849         return kvm_cpuid_base();
 850 }
 851
 852 static void __init kvm_apic_init(void)
 853 {
 854 #ifdef CONFIG_SMP
 855         if (pv_ipi_supported())
 856                 kvm_setup_pv_ipi();
 857 #endif
 858 }
 859
 860 static bool __init kvm_msi_ext_dest_id(void)
 861 {
 862         return kvm_para_has_feature(KVM_FEATURE_MSI_EXT_DEST_ID);
 863 }
 864
 865 static void kvm_sev_hc_page_enc_status(unsigned long pfn, int npages, bool enc)
 866 {
 867         kvm_sev_hypercall3(KVM_HC_MAP_GPA_RANGE, pfn << PAGE_SHIFT, npages,
 868                            KVM_MAP_GPA_RANGE_ENC_STAT(enc) | KVM_MAP_GPA_RANGE_PAGE_SZ_4K);
 869 }
 870
 871 static void __init kvm_init_platform(void)
 872 {
 873         if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT) &&
 874             kvm_para_has_feature(KVM_FEATURE_MIGRATION_CONTROL)) {
 875                 unsigned long nr_pages;
 876                 int i;
 877
 878                 pv_ops.mmu.notify_page_enc_status_changed =
 879                         kvm_sev_hc_page_enc_status;
 880
 881                 /*
 882                  * Reset the host's shared pages list related to kernel
 883                  * specific page encryption status settings before we load a
 884                  * new kernel by kexec. Reset the page encryption status
 885                  * during early boot intead of just before kexec to avoid SMP
 886                  * races during kvm_pv_guest_cpu_reboot().
 887                  * NOTE: We cannot reset the complete shared pages list
 888                  * here as we need to retain the UEFI/OVMF firmware
 889                  * specific settings.
 890                  */
 891
 892                 for (i = 0; i < e820_table->nr_entries; i++) {
 893                         struct e820_entry *entry = &e820_table->entries[i];
 894
 895                         if (entry->type != E820_TYPE_RAM)
 896                                 continue;
 897
 898                         nr_pages = DIV_ROUND_UP(entry->size, PAGE_SIZE);
 899
 900                         kvm_sev_hypercall3(KVM_HC_MAP_GPA_RANGE, entry->addr,
 901                                        nr_pages,
 902                                        KVM_MAP_GPA_RANGE_ENCRYPTED | KVM_MAP_GPA_RANGE_PAGE_SZ_4K);
 903                 }
 904
 905                 /*
 906                  * Ensure that _bss_decrypted section is marked as decrypted in the
 907                  * shared pages list.
 908                  */
 909                 nr_pages = DIV_ROUND_UP(__end_bss_decrypted - __start_bss_decrypted,
 910                                         PAGE_SIZE);
 911                 early_set_mem_enc_dec_hypercall((unsigned long)__start_bss_decrypted,
 912                                                 nr_pages, 0);
 913
 914                 /*
 915                  * If not booted using EFI, enable Live migration support.
 916                  */
 917                 if (!efi_enabled(EFI_BOOT))
 918                         wrmsrl(MSR_KVM_MIGRATION_CONTROL,
 919                                KVM_MIGRATION_READY);
 920         }
 921         kvmclock_init();
 922         x86_platform.apic_post_init = kvm_apic_init;
 923 }
 924
 925 #if defined(CONFIG_AMD_MEM_ENCRYPT)
 926 static void kvm_sev_es_hcall_prepare(struct ghcb *ghcb, struct pt_regs *regs)
 927 {
 928         /* RAX and CPL are already in the GHCB */
 929         ghcb_set_rbx(ghcb, regs->bx);
 930         ghcb_set_rcx(ghcb, regs->cx);
 931         ghcb_set_rdx(ghcb, regs->dx);
 932         ghcb_set_rsi(ghcb, regs->si);
 933 }
 934
 935 static bool kvm_sev_es_hcall_finish(struct ghcb *ghcb, struct pt_regs *regs)
 936 {
 937         /* No checking of the return state needed */
 938         return true;
 939 }
 940 #endif
 941
 942 const __initconst struct hypervisor_x86 x86_hyper_kvm = {
 943         .name                           = "KVM",
 944         .detect                         = kvm_detect,
 945         .type                           = X86_HYPER_KVM,
 946         .init.guest_late_init           = kvm_guest_init,
 947         .init.x2apic_available          = kvm_para_available,
 948         .init.msi_ext_dest_id           = kvm_msi_ext_dest_id,
 949         .init.init_platform             = kvm_init_platform,
 950 #if defined(CONFIG_AMD_MEM_ENCRYPT)
 951         .runtime.sev_es_hcall_prepare   = kvm_sev_es_hcall_prepare,
 952         .runtime.sev_es_hcall_finish    = kvm_sev_es_hcall_finish,
 953 #endif
 954 };
 955
 956 static __init int activate_jump_labels(void)
 957 {
 958         if (has_steal_clock) {
 959                 static_key_slow_inc(&paravirt_steal_enabled);
 960                 if (steal_acc)
 961                         static_key_slow_inc(&paravirt_steal_rq_enabled);
 962         }
 963
 964         return 0;
 965 }
 966 arch_initcall(activate_jump_labels);
 967
 968 #ifdef CONFIG_PARAVIRT_SPINLOCKS
 969
 970 /* Kick a cpu by its apicid. Used to wake up a halted vcpu */
 971 static void kvm_kick_cpu(int cpu)
 972 {
 973         int apicid;
 974         unsigned long flags = 0;
 975
 976         apicid = per_cpu(x86_cpu_to_apicid, cpu);
 977         kvm_hypercall2(KVM_HC_KICK_CPU, flags, apicid);
 978 }
 979
 980 #include <asm/qspinlock.h>
 981
 982 static void kvm_wait(u8 *ptr, u8 val)
 983 {
 984         if (in_nmi())
 985                 return;
 986
 987         /*
 988          * halt until it's our turn and kicked. Note that we do safe halt
 989          * for irq enabled case to avoid hang when lock info is overwritten
 990          * in irq spinlock slowpath and no spurious interrupt occur to save us.
 991          */
 992         if (irqs_disabled()) {
 993                 if (READ_ONCE(*ptr) == val)
 994                         halt();
 995         } else {
 996                 local_irq_disable();
 997
 998                 /* safe_halt() will enable IRQ */
 999                 if (READ_ONCE(*ptr) == val)
1000                         safe_halt();
1001                 else
1002                         local_irq_enable();
1003         }
1004 }
1005
1006 #ifdef CONFIG_X86_32
1007 __visible bool __kvm_vcpu_is_preempted(long cpu)
1008 {
1009         struct kvm_steal_time *src = &per_cpu(steal_time, cpu);
1010
1011         return !!(src->preempted & KVM_VCPU_PREEMPTED);
1012 }
1013 PV_CALLEE_SAVE_REGS_THUNK(__kvm_vcpu_is_preempted);
1014
1015 #else
1016
1017 #include <asm/asm-offsets.h>
1018
1019 extern bool __raw_callee_save___kvm_vcpu_is_preempted(long);
1020
1021 /*
1022  * Hand-optimize version for x86-64 to avoid 8 64-bit register saving and
1023  * restoring to/from the stack.
1024  */
1025 asm(
1026 ".pushsection .text;"
1027 ".global __raw_callee_save___kvm_vcpu_is_preempted;"
1028 ".type __raw_callee_save___kvm_vcpu_is_preempted, @function;"
1029 "__raw_callee_save___kvm_vcpu_is_preempted:"
1030 "movq   __per_cpu_offset(,%rdi,8), %rax;"
1031 "cmpb   $0, " __stringify(KVM_STEAL_TIME_preempted) "+steal_time(%rax);"
1032 "setne  %al;"
1033 "ret;"
1034 ".size __raw_callee_save___kvm_vcpu_is_preempted, .-__raw_callee_save___kvm_vcpu_is_preempted;"
1035 ".popsection");
1036
1037 #endif
1038
1039 /*
1040  * Setup pv_lock_ops to exploit KVM_FEATURE_PV_UNHALT if present.
1041  */
1042 void __init kvm_spinlock_init(void)
1043 {
1044         /*
1045          * In case host doesn't support KVM_FEATURE_PV_UNHALT there is still an
1046          * advantage of keeping virt_spin_lock_key enabled: virt_spin_lock() is
1047          * preferred over native qspinlock when vCPU is preempted.
1048          */
1049         if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT)) {
1050                 pr_info("PV spinlocks disabled, no host support\n");
1051                 return;
1052         }
1053
1054         /*
1055          * Disable PV spinlocks and use native qspinlock when dedicated pCPUs
1056          * are available.
1057          */
1058         if (kvm_para_has_hint(KVM_HINTS_REALTIME)) {
1059                 pr_info("PV spinlocks disabled with KVM_HINTS_REALTIME hints\n");
1060                 goto out;
1061         }
1062
1063         if (num_possible_cpus() == 1) {
1064                 pr_info("PV spinlocks disabled, single CPU\n");
1065                 goto out;
1066         }
1067
1068         if (nopvspin) {
1069                 pr_info("PV spinlocks disabled, forced by \"nopvspin\" parameter\n");
1070                 goto out;
1071         }
1072
1073         pr_info("PV spinlocks enabled\n");
1074
1075         __pv_init_lock_hash();
1076         pv_ops.lock.queued_spin_lock_slowpath = __pv_queued_spin_lock_slowpath;
1077         pv_ops.lock.queued_spin_unlock =
1078                 PV_CALLEE_SAVE(__pv_queued_spin_unlock);
1079         pv_ops.lock.wait = kvm_wait;
1080         pv_ops.lock.kick = kvm_kick_cpu;
1081
1082         if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
1083                 pv_ops.lock.vcpu_is_preempted =
1084                         PV_CALLEE_SAVE(__kvm_vcpu_is_preempted);
1085         }
1086         /*
1087          * When PV spinlock is enabled which is preferred over
1088          * virt_spin_lock(), virt_spin_lock_key's value is meaningless.
1089          * Just disable it anyway.
1090          */
1091 out:
1092         static_branch_disable(&virt_spin_lock_key);
1093 }
1094
1095 #endif  /* CONFIG_PARAVIRT_SPINLOCKS */
1096
1097 #ifdef CONFIG_ARCH_CPUIDLE_HALTPOLL
1098
1099 static void kvm_disable_host_haltpoll(void *i)
1100 {
1101         wrmsrl(MSR_KVM_POLL_CONTROL, 0);
1102 }
1103
1104 static void kvm_enable_host_haltpoll(void *i)
1105 {
1106         wrmsrl(MSR_KVM_POLL_CONTROL, 1);
1107 }
1108
1109 void arch_haltpoll_enable(unsigned int cpu)
1110 {
1111         if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL)) {
1112                 pr_err_once("host does not support poll control\n");
1113                 pr_err_once("host upgrade recommended\n");
1114                 return;
1115         }
1116
1117         /* Enable guest halt poll disables host halt poll */
1118         smp_call_function_single(cpu, kvm_disable_host_haltpoll, NULL, 1);
1119 }
1120 EXPORT_SYMBOL_GPL(arch_haltpoll_enable);
1121
1122 void arch_haltpoll_disable(unsigned int cpu)
1123 {
1124         if (!kvm_para_has_feature(KVM_FEATURE_POLL_CONTROL))
1125                 return;
1126
1127         /* Disable guest halt poll enables host halt poll */
1128         smp_call_function_single(cpu, kvm_enable_host_haltpoll, NULL, 1);
1129 }
1130 EXPORT_SYMBOL_GPL(arch_haltpoll_disable);
1131 #endif