arch/x86/kernel/cpu/vmware.c

   1 /*
   2  * VMware Detection code.
   3  *
   4  * Copyright (C) 2008, VMware, Inc.
   5  * Author : Alok N Kataria <akataria@vmware.com>
   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 #define CPUID_VMWARE_FEATURES_ECX_VMMCALL    BIT(0)
  45 #define CPUID_VMWARE_FEATURES_ECX_VMCALL     BIT(1)
  46
  47 #define VMWARE_HYPERVISOR_MAGIC 0x564D5868
  48
  49 #define VMWARE_CMD_GETVERSION    10
  50 #define VMWARE_CMD_GETHZ         45
  51 #define VMWARE_CMD_GETVCPU_INFO  68
  52 #define VMWARE_CMD_LEGACY_X2APIC  3
  53 #define VMWARE_CMD_VCPU_RESERVED 31
  54 #define VMWARE_CMD_STEALCLOCK    91
  55
  56 #define STEALCLOCK_NOT_AVAILABLE (-1)
  57 #define STEALCLOCK_DISABLED        0
  58 #define STEALCLOCK_ENABLED         1
  59
  60 #define VMWARE_PORT(cmd, eax, ebx, ecx, edx)                            \
  61         __asm__("inl (%%dx), %%eax" :                                   \
  62                 "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) :            \
  63                 "a"(VMWARE_HYPERVISOR_MAGIC),                           \
  64                 "c"(VMWARE_CMD_##cmd),                                  \
  65                 "d"(VMWARE_HYPERVISOR_PORT), "b"(UINT_MAX) :            \
  66                 "memory")
  67
  68 #define VMWARE_VMCALL(cmd, eax, ebx, ecx, edx)                          \
  69         __asm__("vmcall" :                                              \
  70                 "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) :            \
  71                 "a"(VMWARE_HYPERVISOR_MAGIC),                           \
  72                 "c"(VMWARE_CMD_##cmd),                                  \
  73                 "d"(0), "b"(UINT_MAX) :                                 \
  74                 "memory")
  75
  76 #define VMWARE_VMMCALL(cmd, eax, ebx, ecx, edx)                         \
  77         __asm__("vmmcall" :                                             \
  78                 "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) :            \
  79                 "a"(VMWARE_HYPERVISOR_MAGIC),                           \
  80                 "c"(VMWARE_CMD_##cmd),                                  \
  81                 "d"(0), "b"(UINT_MAX) :                                 \
  82                 "memory")
  83
  84 #define VMWARE_CMD(cmd, eax, ebx, ecx, edx) do {                \
  85         switch (vmware_hypercall_mode) {                        \
  86         case CPUID_VMWARE_FEATURES_ECX_VMCALL:                  \
  87                 VMWARE_VMCALL(cmd, eax, ebx, ecx, edx);         \
  88                 break;                                          \
  89         case CPUID_VMWARE_FEATURES_ECX_VMMCALL:                 \
  90                 VMWARE_VMMCALL(cmd, eax, ebx, ecx, edx);        \
  91                 break;                                          \
  92         default:                                                \
  93                 VMWARE_PORT(cmd, eax, ebx, ecx, edx);           \
  94                 break;                                          \
  95         }                                                       \
  96         } while (0)
  97
  98 struct vmware_steal_time {
  99         union {
 100                 uint64_t clock; /* stolen time counter in units of vtsc */
 101                 struct {
 102                         /* only for little-endian */
 103                         uint32_t clock_low;
 104                         uint32_t clock_high;
 105                 };
 106         };
 107         uint64_t reserved[7];
 108 };
 109
 110 static unsigned long vmware_tsc_khz __ro_after_init;
 111 static u8 vmware_hypercall_mode     __ro_after_init;
 112
 113 static inline int __vmware_platform(void)
 114 {
 115         uint32_t eax, ebx, ecx, edx;
 116         VMWARE_CMD(GETVERSION, eax, ebx, ecx, edx);
 117         return eax != (uint32_t)-1 && ebx == VMWARE_HYPERVISOR_MAGIC;
 118 }
 119
 120 static unsigned long vmware_get_tsc_khz(void)
 121 {
 122         return vmware_tsc_khz;
 123 }
 124
 125 #ifdef CONFIG_PARAVIRT
 126 static struct cyc2ns_data vmware_cyc2ns __ro_after_init;
 127 static bool vmw_sched_clock __initdata = true;
 128 static DEFINE_PER_CPU_DECRYPTED(struct vmware_steal_time, vmw_steal_time) __aligned(64);
 129 static bool has_steal_clock;
 130 static bool steal_acc __initdata = true; /* steal time accounting */
 131
 132 static __init int setup_vmw_sched_clock(char *s)
 133 {
 134         vmw_sched_clock = false;
 135         return 0;
 136 }
 137 early_param("no-vmw-sched-clock", setup_vmw_sched_clock);
 138
 139 static __init int parse_no_stealacc(char *arg)
 140 {
 141         steal_acc = false;
 142         return 0;
 143 }
 144 early_param("no-steal-acc", parse_no_stealacc);
 145
 146 static unsigned long long notrace vmware_sched_clock(void)
 147 {
 148         unsigned long long ns;
 149
 150         ns = mul_u64_u32_shr(rdtsc(), vmware_cyc2ns.cyc2ns_mul,
 151                              vmware_cyc2ns.cyc2ns_shift);
 152         ns -= vmware_cyc2ns.cyc2ns_offset;
 153         return ns;
 154 }
 155
 156 static void __init vmware_cyc2ns_setup(void)
 157 {
 158         struct cyc2ns_data *d = &vmware_cyc2ns;
 159         unsigned long long tsc_now = rdtsc();
 160
 161         clocks_calc_mult_shift(&d->cyc2ns_mul, &d->cyc2ns_shift,
 162                                vmware_tsc_khz, NSEC_PER_MSEC, 0);
 163         d->cyc2ns_offset = mul_u64_u32_shr(tsc_now, d->cyc2ns_mul,
 164                                            d->cyc2ns_shift);
 165
 166         pr_info("using clock offset of %llu ns\n", d->cyc2ns_offset);
 167 }
 168
 169 static int vmware_cmd_stealclock(uint32_t arg1, uint32_t arg2)
 170 {
 171         uint32_t result, info;
 172
 173         asm volatile (VMWARE_HYPERCALL :
 174                 "=a"(result),
 175                 "=c"(info) :
 176                 "a"(VMWARE_HYPERVISOR_MAGIC),
 177                 "b"(0),
 178                 "c"(VMWARE_CMD_STEALCLOCK),
 179                 "d"(0),
 180                 "S"(arg1),
 181                 "D"(arg2) :
 182                 "memory");
 183         return result;
 184 }
 185
 186 static bool stealclock_enable(phys_addr_t pa)
 187 {
 188         return vmware_cmd_stealclock(upper_32_bits(pa),
 189                                      lower_32_bits(pa)) == STEALCLOCK_ENABLED;
 190 }
 191
 192 static int __stealclock_disable(void)
 193 {
 194         return vmware_cmd_stealclock(0, 1);
 195 }
 196
 197 static void stealclock_disable(void)
 198 {
 199         __stealclock_disable();
 200 }
 201
 202 static bool vmware_is_stealclock_available(void)
 203 {
 204         return __stealclock_disable() != STEALCLOCK_NOT_AVAILABLE;
 205 }
 206
 207 /**
 208  * vmware_steal_clock() - read the per-cpu steal clock
 209  * @cpu:            the cpu number whose steal clock we want to read
 210  *
 211  * The function reads the steal clock if we are on a 64-bit system, otherwise
 212  * reads it in parts, checking that the high part didn't change in the
 213  * meantime.
 214  *
 215  * Return:
 216  *      The steal clock reading in ns.
 217  */
 218 static uint64_t vmware_steal_clock(int cpu)
 219 {
 220         struct vmware_steal_time *steal = &per_cpu(vmw_steal_time, cpu);
 221         uint64_t clock;
 222
 223         if (IS_ENABLED(CONFIG_64BIT))
 224                 clock = READ_ONCE(steal->clock);
 225         else {
 226                 uint32_t initial_high, low, high;
 227
 228                 do {
 229                         initial_high = READ_ONCE(steal->clock_high);
 230                         /* Do not reorder initial_high and high readings */
 231                         virt_rmb();
 232                         low = READ_ONCE(steal->clock_low);
 233                         /* Keep low reading in between */
 234                         virt_rmb();
 235                         high = READ_ONCE(steal->clock_high);
 236                 } while (initial_high != high);
 237
 238                 clock = ((uint64_t)high << 32) | low;
 239         }
 240
 241         return mul_u64_u32_shr(clock, vmware_cyc2ns.cyc2ns_mul,
 242                              vmware_cyc2ns.cyc2ns_shift);
 243 }
 244
 245 static void vmware_register_steal_time(void)
 246 {
 247         int cpu = smp_processor_id();
 248         struct vmware_steal_time *st = &per_cpu(vmw_steal_time, cpu);
 249
 250         if (!has_steal_clock)
 251                 return;
 252
 253         if (!stealclock_enable(slow_virt_to_phys(st))) {
 254                 has_steal_clock = false;
 255                 return;
 256         }
 257
 258         pr_info("vmware-stealtime: cpu %d, pa %llx\n",
 259                 cpu, (unsigned long long) slow_virt_to_phys(st));
 260 }
 261
 262 static void vmware_disable_steal_time(void)
 263 {
 264         if (!has_steal_clock)
 265                 return;
 266
 267         stealclock_disable();
 268 }
 269
 270 static void vmware_guest_cpu_init(void)
 271 {
 272         if (has_steal_clock)
 273                 vmware_register_steal_time();
 274 }
 275
 276 static void vmware_pv_guest_cpu_reboot(void *unused)
 277 {
 278         vmware_disable_steal_time();
 279 }
 280
 281 static int vmware_pv_reboot_notify(struct notifier_block *nb,
 282                                 unsigned long code, void *unused)
 283 {
 284         if (code == SYS_RESTART)
 285                 on_each_cpu(vmware_pv_guest_cpu_reboot, NULL, 1);
 286         return NOTIFY_DONE;
 287 }
 288
 289 static struct notifier_block vmware_pv_reboot_nb = {
 290         .notifier_call = vmware_pv_reboot_notify,
 291 };
 292
 293 #ifdef CONFIG_SMP
 294 static void __init vmware_smp_prepare_boot_cpu(void)
 295 {
 296         vmware_guest_cpu_init();
 297         native_smp_prepare_boot_cpu();
 298 }
 299
 300 static int vmware_cpu_online(unsigned int cpu)
 301 {
 302         local_irq_disable();
 303         vmware_guest_cpu_init();
 304         local_irq_enable();
 305         return 0;
 306 }
 307
 308 static int vmware_cpu_down_prepare(unsigned int cpu)
 309 {
 310         local_irq_disable();
 311         vmware_disable_steal_time();
 312         local_irq_enable();
 313         return 0;
 314 }
 315 #endif
 316
 317 static __init int activate_jump_labels(void)
 318 {
 319         if (has_steal_clock) {
 320                 static_key_slow_inc(&paravirt_steal_enabled);
 321                 if (steal_acc)
 322                         static_key_slow_inc(&paravirt_steal_rq_enabled);
 323         }
 324
 325         return 0;
 326 }
 327 arch_initcall(activate_jump_labels);
 328
 329 static void __init vmware_paravirt_ops_setup(void)
 330 {
 331         pv_info.name = "VMware hypervisor";
 332         pv_ops.cpu.io_delay = paravirt_nop;
 333
 334         if (vmware_tsc_khz == 0)
 335                 return;
 336
 337         vmware_cyc2ns_setup();
 338
 339         if (vmw_sched_clock)
 340                 paravirt_set_sched_clock(vmware_sched_clock);
 341
 342         if (vmware_is_stealclock_available()) {
 343                 has_steal_clock = true;
 344                 static_call_update(pv_steal_clock, vmware_steal_clock);
 345
 346                 /* We use reboot notifier only to disable steal clock */
 347                 register_reboot_notifier(&vmware_pv_reboot_nb);
 348
 349 #ifdef CONFIG_SMP
 350                 smp_ops.smp_prepare_boot_cpu =
 351                         vmware_smp_prepare_boot_cpu;
 352                 if (cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
 353                                               "x86/vmware:online",
 354                                               vmware_cpu_online,
 355                                               vmware_cpu_down_prepare) < 0)
 356                         pr_err("vmware_guest: Failed to install cpu hotplug callbacks\n");
 357 #else
 358                 vmware_guest_cpu_init();
 359 #endif
 360         }
 361 }
 362 #else
 363 #define vmware_paravirt_ops_setup() do {} while (0)
 364 #endif
 365
 366 /*
 367  * VMware hypervisor takes care of exporting a reliable TSC to the guest.
 368  * Still, due to timing difference when running on virtual cpus, the TSC can
 369  * be marked as unstable in some cases. For example, the TSC sync check at
 370  * bootup can fail due to a marginal offset between vcpus' TSCs (though the
 371  * TSCs do not drift from each other).  Also, the ACPI PM timer clocksource
 372  * is not suitable as a watchdog when running on a hypervisor because the
 373  * kernel may miss a wrap of the counter if the vcpu is descheduled for a
 374  * long time. To skip these checks at runtime we set these capability bits,
 375  * so that the kernel could just trust the hypervisor with providing a
 376  * reliable virtual TSC that is suitable for timekeeping.
 377  */
 378 static void __init vmware_set_capabilities(void)
 379 {
 380         setup_force_cpu_cap(X86_FEATURE_CONSTANT_TSC);
 381         setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
 382         if (vmware_tsc_khz)
 383                 setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
 384         if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMCALL)
 385                 setup_force_cpu_cap(X86_FEATURE_VMCALL);
 386         else if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMMCALL)
 387                 setup_force_cpu_cap(X86_FEATURE_VMW_VMMCALL);
 388 }
 389
 390 static void __init vmware_platform_setup(void)
 391 {
 392         uint32_t eax, ebx, ecx, edx;
 393         uint64_t lpj, tsc_khz;
 394
 395         VMWARE_CMD(GETHZ, eax, ebx, ecx, edx);
 396
 397         if (ebx != UINT_MAX) {
 398                 lpj = tsc_khz = eax | (((uint64_t)ebx) << 32);
 399                 do_div(tsc_khz, 1000);
 400                 WARN_ON(tsc_khz >> 32);
 401                 pr_info("TSC freq read from hypervisor : %lu.%03lu MHz\n",
 402                         (unsigned long) tsc_khz / 1000,
 403                         (unsigned long) tsc_khz % 1000);
 404
 405                 if (!preset_lpj) {
 406                         do_div(lpj, HZ);
 407                         preset_lpj = lpj;
 408                 }
 409
 410                 vmware_tsc_khz = tsc_khz;
 411                 x86_platform.calibrate_tsc = vmware_get_tsc_khz;
 412                 x86_platform.calibrate_cpu = vmware_get_tsc_khz;
 413
 414 #ifdef CONFIG_X86_LOCAL_APIC
 415                 /* Skip lapic calibration since we know the bus frequency. */
 416                 lapic_timer_period = ecx / HZ;
 417                 pr_info("Host bus clock speed read from hypervisor : %u Hz\n",
 418                         ecx);
 419 #endif
 420         } else {
 421                 pr_warn("Failed to get TSC freq from the hypervisor\n");
 422         }
 423
 424         vmware_paravirt_ops_setup();
 425
 426 #ifdef CONFIG_X86_IO_APIC
 427         no_timer_check = 1;
 428 #endif
 429
 430         vmware_set_capabilities();
 431 }
 432
 433 static u8 __init vmware_select_hypercall(void)
 434 {
 435         int eax, ebx, ecx, edx;
 436
 437         cpuid(CPUID_VMWARE_FEATURES_LEAF, &eax, &ebx, &ecx, &edx);
 438         return (ecx & (CPUID_VMWARE_FEATURES_ECX_VMMCALL |
 439                        CPUID_VMWARE_FEATURES_ECX_VMCALL));
 440 }
 441
 442 /*
 443  * While checking the dmi string information, just checking the product
 444  * serial key should be enough, as this will always have a VMware
 445  * specific string when running under VMware hypervisor.
 446  * If !boot_cpu_has(X86_FEATURE_HYPERVISOR), vmware_hypercall_mode
 447  * intentionally defaults to 0.
 448  */
 449 static uint32_t __init vmware_platform(void)
 450 {
 451         if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
 452                 unsigned int eax;
 453                 unsigned int hyper_vendor_id[3];
 454
 455                 cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0],
 456                       &hyper_vendor_id[1], &hyper_vendor_id[2]);
 457                 if (!memcmp(hyper_vendor_id, "VMwareVMware", 12)) {
 458                         if (eax >= CPUID_VMWARE_FEATURES_LEAF)
 459                                 vmware_hypercall_mode =
 460                                         vmware_select_hypercall();
 461
 462                         pr_info("hypercall mode: 0x%02x\n",
 463                                 (unsigned int) vmware_hypercall_mode);
 464
 465                         return CPUID_VMWARE_INFO_LEAF;
 466                 }
 467         } else if (dmi_available && dmi_name_in_serial("VMware") &&
 468                    __vmware_platform())
 469                 return 1;
 470
 471         return 0;
 472 }
 473
 474 /* Checks if hypervisor supports x2apic without VT-D interrupt remapping. */
 475 static bool __init vmware_legacy_x2apic_available(void)
 476 {
 477         uint32_t eax, ebx, ecx, edx;
 478         VMWARE_CMD(GETVCPU_INFO, eax, ebx, ecx, edx);
 479         return (eax & (1 << VMWARE_CMD_VCPU_RESERVED)) == 0 &&
 480                (eax & (1 << VMWARE_CMD_LEGACY_X2APIC)) != 0;
 481 }
 482
 483 #ifdef CONFIG_AMD_MEM_ENCRYPT
 484 static void vmware_sev_es_hcall_prepare(struct ghcb *ghcb,
 485                                         struct pt_regs *regs)
 486 {
 487         /* Copy VMWARE specific Hypercall parameters to the GHCB */
 488         ghcb_set_rip(ghcb, regs->ip);
 489         ghcb_set_rbx(ghcb, regs->bx);
 490         ghcb_set_rcx(ghcb, regs->cx);
 491         ghcb_set_rdx(ghcb, regs->dx);
 492         ghcb_set_rsi(ghcb, regs->si);
 493         ghcb_set_rdi(ghcb, regs->di);
 494         ghcb_set_rbp(ghcb, regs->bp);
 495 }
 496
 497 static bool vmware_sev_es_hcall_finish(struct ghcb *ghcb, struct pt_regs *regs)
 498 {
 499         if (!(ghcb_rbx_is_valid(ghcb) &&
 500               ghcb_rcx_is_valid(ghcb) &&
 501               ghcb_rdx_is_valid(ghcb) &&
 502               ghcb_rsi_is_valid(ghcb) &&
 503               ghcb_rdi_is_valid(ghcb) &&
 504               ghcb_rbp_is_valid(ghcb)))
 505                 return false;
 506
 507         regs->bx = ghcb_get_rbx(ghcb);
 508         regs->cx = ghcb_get_rcx(ghcb);
 509         regs->dx = ghcb_get_rdx(ghcb);
 510         regs->si = ghcb_get_rsi(ghcb);
 511         regs->di = ghcb_get_rdi(ghcb);
 512         regs->bp = ghcb_get_rbp(ghcb);
 513
 514         return true;
 515 }
 516 #endif
 517
 518 const __initconst struct hypervisor_x86 x86_hyper_vmware = {
 519         .name                           = "VMware",
 520         .detect                         = vmware_platform,
 521         .type                           = X86_HYPER_VMWARE,
 522         .init.init_platform             = vmware_platform_setup,
 523         .init.x2apic_available          = vmware_legacy_x2apic_available,
 524 #ifdef CONFIG_AMD_MEM_ENCRYPT
 525         .runtime.sev_es_hcall_prepare   = vmware_sev_es_hcall_prepare,
 526         .runtime.sev_es_hcall_finish    = vmware_sev_es_hcall_finish,
 527 #endif
 528 };