arch/x86/kernel/cpu/vmware.c

   1 /*
   2  * VMware Detection code.
   3  *
   4  * Copyright (C) 2008, VMware, Inc.
   5  * Author : Alok N Kataria <[email protected]>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  15  * NON INFRINGEMENT.  See the GNU General Public License for more
  16  * details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  21  *
  22  */
  23
  24 #include <linux/dmi.h>
  25 #include <linux/init.h>
  26 #include <linux/export.h>
  27 #include <linux/clocksource.h>
  28 #include <linux/cpu.h>
  29 #include <linux/reboot.h>
  30 #include <linux/static_call.h>
  31 #include <asm/div64.h>
  32 #include <asm/x86_init.h>
  33 #include <asm/hypervisor.h>
  34 #include <asm/timer.h>
  35 #include <asm/apic.h>
  36 #include <asm/vmware.h>
  37 #include <asm/svm.h>
  38
  39 #undef pr_fmt
  40 #define pr_fmt(fmt)     "vmware: " fmt
  41
  42 #define CPUID_VMWARE_INFO_LEAF               0x40000000
  43 #define CPUID_VMWARE_FEATURES_LEAF           0x40000010
  44
  45 #define GETVCPU_INFO_LEGACY_X2APIC           BIT(3)
  46 #define GETVCPU_INFO_VCPU_RESERVED           BIT(31)
  47
  48 #define STEALCLOCK_NOT_AVAILABLE (-1)
  49 #define STEALCLOCK_DISABLED        0
  50 #define STEALCLOCK_ENABLED         1
  51
  52 struct vmware_steal_time {
  53         union {
  54                 u64 clock;      /* stolen time counter in units of vtsc */
  55                 struct {
  56                         /* only for little-endian */
  57                         u32 clock_low;
  58                         u32 clock_high;
  59                 };
  60         };
  61         u64 reserved[7];
  62 };
  63
  64 static unsigned long vmware_tsc_khz __ro_after_init;
  65 static u8 vmware_hypercall_mode     __ro_after_init;
  66
  67 unsigned long vmware_hypercall_slow(unsigned long cmd,
  68                                     unsigned long in1, unsigned long in3,
  69                                     unsigned long in4, unsigned long in5,
  70                                     u32 *out1, u32 *out2, u32 *out3,
  71                                     u32 *out4, u32 *out5)
  72 {
  73         unsigned long out0, rbx, rcx, rdx, rsi, rdi;
  74
  75         switch (vmware_hypercall_mode) {
  76         case CPUID_VMWARE_FEATURES_ECX_VMCALL:
  77                 asm_inline volatile ("vmcall"
  78                                 : "=a" (out0), "=b" (rbx), "=c" (rcx),
  79                                 "=d" (rdx), "=S" (rsi), "=D" (rdi)
  80                                 : "a" (VMWARE_HYPERVISOR_MAGIC),
  81                                 "b" (in1),
  82                                 "c" (cmd),
  83                                 "d" (in3),
  84                                 "S" (in4),
  85                                 "D" (in5)
  86                                 : "cc", "memory");
  87                 break;
  88         case CPUID_VMWARE_FEATURES_ECX_VMMCALL:
  89                 asm_inline volatile ("vmmcall"
  90                                 : "=a" (out0), "=b" (rbx), "=c" (rcx),
  91                                 "=d" (rdx), "=S" (rsi), "=D" (rdi)
  92                                 : "a" (VMWARE_HYPERVISOR_MAGIC),
  93                                 "b" (in1),
  94                                 "c" (cmd),
  95                                 "d" (in3),
  96                                 "S" (in4),
  97                                 "D" (in5)
  98                                 : "cc", "memory");
  99                 break;
 100         default:
 101                 asm_inline volatile ("movw %[port], %%dx; inl (%%dx), %%eax"
 102                                 : "=a" (out0), "=b" (rbx), "=c" (rcx),
 103                                 "=d" (rdx), "=S" (rsi), "=D" (rdi)
 104                                 : [port] "i" (VMWARE_HYPERVISOR_PORT),
 105                                 "a" (VMWARE_HYPERVISOR_MAGIC),
 106                                 "b" (in1),
 107                                 "c" (cmd),
 108                                 "d" (in3),
 109                                 "S" (in4),
 110                                 "D" (in5)
 111                                 : "cc", "memory");
 112                 break;
 113         }
 114
 115         if (out1)
 116                 *out1 = rbx;
 117         if (out2)
 118                 *out2 = rcx;
 119         if (out3)
 120                 *out3 = rdx;
 121         if (out4)
 122                 *out4 = rsi;
 123         if (out5)
 124                 *out5 = rdi;
 125
 126         return out0;
 127 }
 128
 129 static inline int __vmware_platform(void)
 130 {
 131         u32 eax, ebx, ecx;
 132
 133         eax = vmware_hypercall3(VMWARE_CMD_GETVERSION, 0, &ebx, &ecx);
 134         return eax != UINT_MAX && ebx == VMWARE_HYPERVISOR_MAGIC;
 135 }
 136
 137 static unsigned long vmware_get_tsc_khz(void)
 138 {
 139         return vmware_tsc_khz;
 140 }
 141
 142 #ifdef CONFIG_PARAVIRT
 143 static struct cyc2ns_data vmware_cyc2ns __ro_after_init;
 144 static bool vmw_sched_clock __initdata = true;
 145 static DEFINE_PER_CPU_DECRYPTED(struct vmware_steal_time, vmw_steal_time) __aligned(64);
 146 static bool has_steal_clock;
 147 static bool steal_acc __initdata = true; /* steal time accounting */
 148
 149 static __init int setup_vmw_sched_clock(char *s)
 150 {
 151         vmw_sched_clock = false;
 152         return 0;
 153 }
 154 early_param("no-vmw-sched-clock", setup_vmw_sched_clock);
 155
 156 static __init int parse_no_stealacc(char *arg)
 157 {
 158         steal_acc = false;
 159         return 0;
 160 }
 161 early_param("no-steal-acc", parse_no_stealacc);
 162
 163 static noinstr u64 vmware_sched_clock(void)
 164 {
 165         unsigned long long ns;
 166
 167         ns = mul_u64_u32_shr(rdtsc(), vmware_cyc2ns.cyc2ns_mul,
 168                              vmware_cyc2ns.cyc2ns_shift);
 169         ns -= vmware_cyc2ns.cyc2ns_offset;
 170         return ns;
 171 }
 172
 173 static void __init vmware_cyc2ns_setup(void)
 174 {
 175         struct cyc2ns_data *d = &vmware_cyc2ns;
 176         unsigned long long tsc_now = rdtsc();
 177
 178         clocks_calc_mult_shift(&d->cyc2ns_mul, &d->cyc2ns_shift,
 179                                vmware_tsc_khz, NSEC_PER_MSEC, 0);
 180         d->cyc2ns_offset = mul_u64_u32_shr(tsc_now, d->cyc2ns_mul,
 181                                            d->cyc2ns_shift);
 182
 183         pr_info("using clock offset of %llu ns\n", d->cyc2ns_offset);
 184 }
 185
 186 static int vmware_cmd_stealclock(u32 addr_hi, u32 addr_lo)
 187 {
 188         u32 info;
 189
 190         return vmware_hypercall5(VMWARE_CMD_STEALCLOCK, 0, 0, addr_hi, addr_lo,
 191                                  &info);
 192 }
 193
 194 static bool stealclock_enable(phys_addr_t pa)
 195 {
 196         return vmware_cmd_stealclock(upper_32_bits(pa),
 197                                      lower_32_bits(pa)) == STEALCLOCK_ENABLED;
 198 }
 199
 200 static int __stealclock_disable(void)
 201 {
 202         return vmware_cmd_stealclock(0, 1);
 203 }
 204
 205 static void stealclock_disable(void)
 206 {
 207         __stealclock_disable();
 208 }
 209
 210 static bool vmware_is_stealclock_available(void)
 211 {
 212         return __stealclock_disable() != STEALCLOCK_NOT_AVAILABLE;
 213 }
 214
 215 /**
 216  * vmware_steal_clock() - read the per-cpu steal clock
 217  * @cpu:            the cpu number whose steal clock we want to read
 218  *
 219  * The function reads the steal clock if we are on a 64-bit system, otherwise
 220  * reads it in parts, checking that the high part didn't change in the
 221  * meantime.
 222  *
 223  * Return:
 224  *      The steal clock reading in ns.
 225  */
 226 static u64 vmware_steal_clock(int cpu)
 227 {
 228         struct vmware_steal_time *steal = &per_cpu(vmw_steal_time, cpu);
 229         u64 clock;
 230
 231         if (IS_ENABLED(CONFIG_64BIT))
 232                 clock = READ_ONCE(steal->clock);
 233         else {
 234                 u32 initial_high, low, high;
 235
 236                 do {
 237                         initial_high = READ_ONCE(steal->clock_high);
 238                         /* Do not reorder initial_high and high readings */
 239                         virt_rmb();
 240                         low = READ_ONCE(steal->clock_low);
 241                         /* Keep low reading in between */
 242                         virt_rmb();
 243                         high = READ_ONCE(steal->clock_high);
 244                 } while (initial_high != high);
 245
 246                 clock = ((u64)high << 32) | low;
 247         }
 248
 249         return mul_u64_u32_shr(clock, vmware_cyc2ns.cyc2ns_mul,
 250                              vmware_cyc2ns.cyc2ns_shift);
 251 }
 252
 253 static void vmware_register_steal_time(void)
 254 {
 255         int cpu = smp_processor_id();
 256         struct vmware_steal_time *st = &per_cpu(vmw_steal_time, cpu);
 257
 258         if (!has_steal_clock)
 259                 return;
 260
 261         if (!stealclock_enable(slow_virt_to_phys(st))) {
 262                 has_steal_clock = false;
 263                 return;
 264         }
 265
 266         pr_info("vmware-stealtime: cpu %d, pa %llx\n",
 267                 cpu, (unsigned long long) slow_virt_to_phys(st));
 268 }
 269
 270 static void vmware_disable_steal_time(void)
 271 {
 272         if (!has_steal_clock)
 273                 return;
 274
 275         stealclock_disable();
 276 }
 277
 278 static void vmware_guest_cpu_init(void)
 279 {
 280         if (has_steal_clock)
 281                 vmware_register_steal_time();
 282 }
 283
 284 static void vmware_pv_guest_cpu_reboot(void *unused)
 285 {
 286         vmware_disable_steal_time();
 287 }
 288
 289 static int vmware_pv_reboot_notify(struct notifier_block *nb,
 290                                 unsigned long code, void *unused)
 291 {
 292         if (code == SYS_RESTART)
 293                 on_each_cpu(vmware_pv_guest_cpu_reboot, NULL, 1);
 294         return NOTIFY_DONE;
 295 }
 296
 297 static struct notifier_block vmware_pv_reboot_nb = {
 298         .notifier_call = vmware_pv_reboot_notify,
 299 };
 300
 301 #ifdef CONFIG_SMP
 302 static void __init vmware_smp_prepare_boot_cpu(void)
 303 {
 304         vmware_guest_cpu_init();
 305         native_smp_prepare_boot_cpu();
 306 }
 307
 308 static int vmware_cpu_online(unsigned int cpu)
 309 {
 310         local_irq_disable();
 311         vmware_guest_cpu_init();
 312         local_irq_enable();
 313         return 0;
 314 }
 315
 316 static int vmware_cpu_down_prepare(unsigned int cpu)
 317 {
 318         local_irq_disable();
 319         vmware_disable_steal_time();
 320         local_irq_enable();
 321         return 0;
 322 }
 323 #endif
 324
 325 static __init int activate_jump_labels(void)
 326 {
 327         if (has_steal_clock) {
 328                 static_key_slow_inc(&paravirt_steal_enabled);
 329                 if (steal_acc)
 330                         static_key_slow_inc(&paravirt_steal_rq_enabled);
 331         }
 332
 333         return 0;
 334 }
 335 arch_initcall(activate_jump_labels);
 336
 337 static void __init vmware_paravirt_ops_setup(void)
 338 {
 339         pv_info.name = "VMware hypervisor";
 340         pv_ops.cpu.io_delay = paravirt_nop;
 341
 342         if (vmware_tsc_khz == 0)
 343                 return;
 344
 345         vmware_cyc2ns_setup();
 346
 347         if (vmw_sched_clock)
 348                 paravirt_set_sched_clock(vmware_sched_clock);
 349
 350         if (vmware_is_stealclock_available()) {
 351                 has_steal_clock = true;
 352                 static_call_update(pv_steal_clock, vmware_steal_clock);
 353
 354                 /* We use reboot notifier only to disable steal clock */
 355                 register_reboot_notifier(&vmware_pv_reboot_nb);
 356
 357 #ifdef CONFIG_SMP
 358                 smp_ops.smp_prepare_boot_cpu =
 359                         vmware_smp_prepare_boot_cpu;
 360                 if (cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
 361                                               "x86/vmware:online",
 362                                               vmware_cpu_online,
 363                                               vmware_cpu_down_prepare) < 0)
 364                         pr_err("vmware_guest: Failed to install cpu hotplug callbacks\n");
 365 #else
 366                 vmware_guest_cpu_init();
 367 #endif
 368         }
 369 }
 370 #else
 371 #define vmware_paravirt_ops_setup() do {} while (0)
 372 #endif
 373
 374 /*
 375  * VMware hypervisor takes care of exporting a reliable TSC to the guest.
 376  * Still, due to timing difference when running on virtual cpus, the TSC can
 377  * be marked as unstable in some cases. For example, the TSC sync check at
 378  * bootup can fail due to a marginal offset between vcpus' TSCs (though the
 379  * TSCs do not drift from each other).  Also, the ACPI PM timer clocksource
 380  * is not suitable as a watchdog when running on a hypervisor because the
 381  * kernel may miss a wrap of the counter if the vcpu is descheduled for a
 382  * long time. To skip these checks at runtime we set these capability bits,
 383  * so that the kernel could just trust the hypervisor with providing a
 384  * reliable virtual TSC that is suitable for timekeeping.
 385  */
 386 static void __init vmware_set_capabilities(void)
 387 {
 388         setup_force_cpu_cap(X86_FEATURE_CONSTANT_TSC);
 389         setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
 390         if (vmware_tsc_khz)
 391                 setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
 392         if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMCALL)
 393                 setup_force_cpu_cap(X86_FEATURE_VMCALL);
 394         else if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMMCALL)
 395                 setup_force_cpu_cap(X86_FEATURE_VMW_VMMCALL);
 396 }
 397
 398 static void __init vmware_platform_setup(void)
 399 {
 400         u32 eax, ebx, ecx;
 401         u64 lpj, tsc_khz;
 402
 403         eax = vmware_hypercall3(VMWARE_CMD_GETHZ, UINT_MAX, &ebx, &ecx);
 404
 405         if (ebx != UINT_MAX) {
 406                 lpj = tsc_khz = eax | (((u64)ebx) << 32);
 407                 do_div(tsc_khz, 1000);
 408                 WARN_ON(tsc_khz >> 32);
 409                 pr_info("TSC freq read from hypervisor : %lu.%03lu MHz\n",
 410                         (unsigned long) tsc_khz / 1000,
 411                         (unsigned long) tsc_khz % 1000);
 412
 413                 if (!preset_lpj) {
 414                         do_div(lpj, HZ);
 415                         preset_lpj = lpj;
 416                 }
 417
 418                 vmware_tsc_khz = tsc_khz;
 419                 x86_platform.calibrate_tsc = vmware_get_tsc_khz;
 420                 x86_platform.calibrate_cpu = vmware_get_tsc_khz;
 421
 422 #ifdef CONFIG_X86_LOCAL_APIC
 423                 /* Skip lapic calibration since we know the bus frequency. */
 424                 lapic_timer_period = ecx / HZ;
 425                 pr_info("Host bus clock speed read from hypervisor : %u Hz\n",
 426                         ecx);
 427 #endif
 428         } else {
 429                 pr_warn("Failed to get TSC freq from the hypervisor\n");
 430         }
 431
 432         vmware_paravirt_ops_setup();
 433
 434 #ifdef CONFIG_X86_IO_APIC
 435         no_timer_check = 1;
 436 #endif
 437
 438         vmware_set_capabilities();
 439 }
 440
 441 static u8 __init vmware_select_hypercall(void)
 442 {
 443         int eax, ebx, ecx, edx;
 444
 445         cpuid(CPUID_VMWARE_FEATURES_LEAF, &eax, &ebx, &ecx, &edx);
 446         return (ecx & (CPUID_VMWARE_FEATURES_ECX_VMMCALL |
 447                        CPUID_VMWARE_FEATURES_ECX_VMCALL));
 448 }
 449
 450 /*
 451  * While checking the dmi string information, just checking the product
 452  * serial key should be enough, as this will always have a VMware
 453  * specific string when running under VMware hypervisor.
 454  * If !boot_cpu_has(X86_FEATURE_HYPERVISOR), vmware_hypercall_mode
 455  * intentionally defaults to 0.
 456  */
 457 static u32 __init vmware_platform(void)
 458 {
 459         if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
 460                 unsigned int eax;
 461                 unsigned int hyper_vendor_id[3];
 462
 463                 cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0],
 464                       &hyper_vendor_id[1], &hyper_vendor_id[2]);
 465                 if (!memcmp(hyper_vendor_id, "VMwareVMware", 12)) {
 466                         if (eax >= CPUID_VMWARE_FEATURES_LEAF)
 467                                 vmware_hypercall_mode =
 468                                         vmware_select_hypercall();
 469
 470                         pr_info("hypercall mode: 0x%02x\n",
 471                                 (unsigned int) vmware_hypercall_mode);
 472
 473                         return CPUID_VMWARE_INFO_LEAF;
 474                 }
 475         } else if (dmi_available && dmi_name_in_serial("VMware") &&
 476                    __vmware_platform())
 477                 return 1;
 478
 479         return 0;
 480 }
 481
 482 /* Checks if hypervisor supports x2apic without VT-D interrupt remapping. */
 483 static bool __init vmware_legacy_x2apic_available(void)
 484 {
 485         u32 eax;
 486
 487         eax = vmware_hypercall1(VMWARE_CMD_GETVCPU_INFO, 0);
 488         return !(eax & GETVCPU_INFO_VCPU_RESERVED) &&
 489                 (eax & GETVCPU_INFO_LEGACY_X2APIC);
 490 }
 491
 492 #ifdef CONFIG_INTEL_TDX_GUEST
 493 /*
 494  * TDCALL[TDG.VP.VMCALL] uses %rax (arg0) and %rcx (arg2). Therefore,
 495  * we remap those registers to %r12 and %r13, respectively.
 496  */
 497 unsigned long vmware_tdx_hypercall(unsigned long cmd,
 498                                    unsigned long in1, unsigned long in3,
 499                                    unsigned long in4, unsigned long in5,
 500                                    u32 *out1, u32 *out2, u32 *out3,
 501                                    u32 *out4, u32 *out5)
 502 {
 503         struct tdx_module_args args = {};
 504
 505         if (!hypervisor_is_type(X86_HYPER_VMWARE)) {
 506                 pr_warn_once("Incorrect usage\n");
 507                 return ULONG_MAX;
 508         }
 509
 510         if (cmd & ~VMWARE_CMD_MASK) {
 511                 pr_warn_once("Out of range command %lx\n", cmd);
 512                 return ULONG_MAX;
 513         }
 514
 515         args.rbx = in1;
 516         args.rdx = in3;
 517         args.rsi = in4;
 518         args.rdi = in5;
 519         args.r10 = VMWARE_TDX_VENDOR_LEAF;
 520         args.r11 = VMWARE_TDX_HCALL_FUNC;
 521         args.r12 = VMWARE_HYPERVISOR_MAGIC;
 522         args.r13 = cmd;
 523         /* CPL */
 524         args.r15 = 0;
 525
 526         __tdx_hypercall(&args);
 527
 528         if (out1)
 529                 *out1 = args.rbx;
 530         if (out2)
 531                 *out2 = args.r13;
 532         if (out3)
 533                 *out3 = args.rdx;
 534         if (out4)
 535                 *out4 = args.rsi;
 536         if (out5)
 537                 *out5 = args.rdi;
 538
 539         return args.r12;
 540 }
 541 EXPORT_SYMBOL_GPL(vmware_tdx_hypercall);
 542 #endif
 543
 544 #ifdef CONFIG_AMD_MEM_ENCRYPT
 545 static void vmware_sev_es_hcall_prepare(struct ghcb *ghcb,
 546                                         struct pt_regs *regs)
 547 {
 548         /* Copy VMWARE specific Hypercall parameters to the GHCB */
 549         ghcb_set_rip(ghcb, regs->ip);
 550         ghcb_set_rbx(ghcb, regs->bx);
 551         ghcb_set_rcx(ghcb, regs->cx);
 552         ghcb_set_rdx(ghcb, regs->dx);
 553         ghcb_set_rsi(ghcb, regs->si);
 554         ghcb_set_rdi(ghcb, regs->di);
 555         ghcb_set_rbp(ghcb, regs->bp);
 556 }
 557
 558 static bool vmware_sev_es_hcall_finish(struct ghcb *ghcb, struct pt_regs *regs)
 559 {
 560         if (!(ghcb_rbx_is_valid(ghcb) &&
 561               ghcb_rcx_is_valid(ghcb) &&
 562               ghcb_rdx_is_valid(ghcb) &&
 563               ghcb_rsi_is_valid(ghcb) &&
 564               ghcb_rdi_is_valid(ghcb) &&
 565               ghcb_rbp_is_valid(ghcb)))
 566                 return false;
 567
 568         regs->bx = ghcb_get_rbx(ghcb);
 569         regs->cx = ghcb_get_rcx(ghcb);
 570         regs->dx = ghcb_get_rdx(ghcb);
 571         regs->si = ghcb_get_rsi(ghcb);
 572         regs->di = ghcb_get_rdi(ghcb);
 573         regs->bp = ghcb_get_rbp(ghcb);
 574
 575         return true;
 576 }
 577 #endif
 578
 579 const __initconst struct hypervisor_x86 x86_hyper_vmware = {
 580         .name                           = "VMware",
 581         .detect                         = vmware_platform,
 582         .type                           = X86_HYPER_VMWARE,
 583         .init.init_platform             = vmware_platform_setup,
 584         .init.x2apic_available          = vmware_legacy_x2apic_available,
 585 #ifdef CONFIG_AMD_MEM_ENCRYPT
 586         .runtime.sev_es_hcall_prepare   = vmware_sev_es_hcall_prepare,
 587         .runtime.sev_es_hcall_finish    = vmware_sev_es_hcall_finish,
 588 #endif
 589 };