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 <asm/div64.h>
  31 #include <asm/x86_init.h>
  32 #include <asm/hypervisor.h>
  33 #include <asm/timer.h>
  34 #include <asm/apic.h>
  35 #include <asm/vmware.h>
  36 #include <asm/svm.h>
  37
  38 #undef pr_fmt
  39 #define pr_fmt(fmt)     "vmware: " fmt
  40
  41 #define CPUID_VMWARE_INFO_LEAF               0x40000000
  42 #define CPUID_VMWARE_FEATURES_LEAF           0x40000010
  43 #define CPUID_VMWARE_FEATURES_ECX_VMMCALL    BIT(0)
  44 #define CPUID_VMWARE_FEATURES_ECX_VMCALL     BIT(1)
  45
  46 #define VMWARE_HYPERVISOR_MAGIC 0x564D5868
  47
  48 #define VMWARE_CMD_GETVERSION    10
  49 #define VMWARE_CMD_GETHZ         45
  50 #define VMWARE_CMD_GETVCPU_INFO  68
  51 #define VMWARE_CMD_LEGACY_X2APIC  3
  52 #define VMWARE_CMD_VCPU_RESERVED 31
  53 #define VMWARE_CMD_STEALCLOCK    91
  54
  55 #define STEALCLOCK_NOT_AVAILABLE (-1)
  56 #define STEALCLOCK_DISABLED        0
  57 #define STEALCLOCK_ENABLED         1
  58
  59 #define VMWARE_PORT(cmd, eax, ebx, ecx, edx)                            \
  60         __asm__("inl (%%dx), %%eax" :                                   \
  61                 "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) :            \
  62                 "a"(VMWARE_HYPERVISOR_MAGIC),                           \
  63                 "c"(VMWARE_CMD_##cmd),                                  \
  64                 "d"(VMWARE_HYPERVISOR_PORT), "b"(UINT_MAX) :            \
  65                 "memory")
  66
  67 #define VMWARE_VMCALL(cmd, eax, ebx, ecx, edx)                          \
  68         __asm__("vmcall" :                                              \
  69                 "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) :            \
  70                 "a"(VMWARE_HYPERVISOR_MAGIC),                           \
  71                 "c"(VMWARE_CMD_##cmd),                                  \
  72                 "d"(0), "b"(UINT_MAX) :                                 \
  73                 "memory")
  74
  75 #define VMWARE_VMMCALL(cmd, eax, ebx, ecx, edx)                         \
  76         __asm__("vmmcall" :                                             \
  77                 "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) :            \
  78                 "a"(VMWARE_HYPERVISOR_MAGIC),                           \
  79                 "c"(VMWARE_CMD_##cmd),                                  \
  80                 "d"(0), "b"(UINT_MAX) :                                 \
  81                 "memory")
  82
  83 #define VMWARE_CMD(cmd, eax, ebx, ecx, edx) do {                \
  84         switch (vmware_hypercall_mode) {                        \
  85         case CPUID_VMWARE_FEATURES_ECX_VMCALL:                  \
  86                 VMWARE_VMCALL(cmd, eax, ebx, ecx, edx);         \
  87                 break;                                          \
  88         case CPUID_VMWARE_FEATURES_ECX_VMMCALL:                 \
  89                 VMWARE_VMMCALL(cmd, eax, ebx, ecx, edx);        \
  90                 break;                                          \
  91         default:                                                \
  92                 VMWARE_PORT(cmd, eax, ebx, ecx, edx);           \
  93                 break;                                          \
  94         }                                                       \
  95         } while (0)
  96
  97 struct vmware_steal_time {
  98         union {
  99                 uint64_t clock; /* stolen time counter in units of vtsc */
 100                 struct {
 101                         /* only for little-endian */
 102                         uint32_t clock_low;
 103                         uint32_t clock_high;
 104                 };
 105         };
 106         uint64_t reserved[7];
 107 };
 108
 109 static unsigned long vmware_tsc_khz __ro_after_init;
 110 static u8 vmware_hypercall_mode     __ro_after_init;
 111
 112 static inline int __vmware_platform(void)
 113 {
 114         uint32_t eax, ebx, ecx, edx;
 115         VMWARE_CMD(GETVERSION, eax, ebx, ecx, edx);
 116         return eax != (uint32_t)-1 && ebx == VMWARE_HYPERVISOR_MAGIC;
 117 }
 118
 119 static unsigned long vmware_get_tsc_khz(void)
 120 {
 121         return vmware_tsc_khz;
 122 }
 123
 124 #ifdef CONFIG_PARAVIRT
 125 static struct cyc2ns_data vmware_cyc2ns __ro_after_init;
 126 static bool vmw_sched_clock __initdata = true;
 127 static DEFINE_PER_CPU_DECRYPTED(struct vmware_steal_time, vmw_steal_time) __aligned(64);
 128 static bool has_steal_clock;
 129 static bool steal_acc __initdata = true; /* steal time accounting */
 130
 131 static __init int setup_vmw_sched_clock(char *s)
 132 {
 133         vmw_sched_clock = false;
 134         return 0;
 135 }
 136 early_param("no-vmw-sched-clock", setup_vmw_sched_clock);
 137
 138 static __init int parse_no_stealacc(char *arg)
 139 {
 140         steal_acc = false;
 141         return 0;
 142 }
 143 early_param("no-steal-acc", parse_no_stealacc);
 144
 145 static unsigned long long notrace vmware_sched_clock(void)
 146 {
 147         unsigned long long ns;
 148
 149         ns = mul_u64_u32_shr(rdtsc(), vmware_cyc2ns.cyc2ns_mul,
 150                              vmware_cyc2ns.cyc2ns_shift);
 151         ns -= vmware_cyc2ns.cyc2ns_offset;
 152         return ns;
 153 }
 154
 155 static void __init vmware_cyc2ns_setup(void)
 156 {
 157         struct cyc2ns_data *d = &vmware_cyc2ns;
 158         unsigned long long tsc_now = rdtsc();
 159
 160         clocks_calc_mult_shift(&d->cyc2ns_mul, &d->cyc2ns_shift,
 161                                vmware_tsc_khz, NSEC_PER_MSEC, 0);
 162         d->cyc2ns_offset = mul_u64_u32_shr(tsc_now, d->cyc2ns_mul,
 163                                            d->cyc2ns_shift);
 164
 165         pr_info("using clock offset of %llu ns\n", d->cyc2ns_offset);
 166 }
 167
 168 static int vmware_cmd_stealclock(uint32_t arg1, uint32_t arg2)
 169 {
 170         uint32_t result, info;
 171
 172         asm volatile (VMWARE_HYPERCALL :
 173                 "=a"(result),
 174                 "=c"(info) :
 175                 "a"(VMWARE_HYPERVISOR_MAGIC),
 176                 "b"(0),
 177                 "c"(VMWARE_CMD_STEALCLOCK),
 178                 "d"(0),
 179                 "S"(arg1),
 180                 "D"(arg2) :
 181                 "memory");
 182         return result;
 183 }
 184
 185 static bool stealclock_enable(phys_addr_t pa)
 186 {
 187         return vmware_cmd_stealclock(upper_32_bits(pa),
 188                                      lower_32_bits(pa)) == STEALCLOCK_ENABLED;
 189 }
 190
 191 static int __stealclock_disable(void)
 192 {
 193         return vmware_cmd_stealclock(0, 1);
 194 }
 195
 196 static void stealclock_disable(void)
 197 {
 198         __stealclock_disable();
 199 }
 200
 201 static bool vmware_is_stealclock_available(void)
 202 {
 203         return __stealclock_disable() != STEALCLOCK_NOT_AVAILABLE;
 204 }
 205
 206 /**
 207  * vmware_steal_clock() - read the per-cpu steal clock
 208  * @cpu:            the cpu number whose steal clock we want to read
 209  *
 210  * The function reads the steal clock if we are on a 64-bit system, otherwise
 211  * reads it in parts, checking that the high part didn't change in the
 212  * meantime.
 213  *
 214  * Return:
 215  *      The steal clock reading in ns.
 216  */
 217 static uint64_t vmware_steal_clock(int cpu)
 218 {
 219         struct vmware_steal_time *steal = &per_cpu(vmw_steal_time, cpu);
 220         uint64_t clock;
 221
 222         if (IS_ENABLED(CONFIG_64BIT))
 223                 clock = READ_ONCE(steal->clock);
 224         else {
 225                 uint32_t initial_high, low, high;
 226
 227                 do {
 228                         initial_high = READ_ONCE(steal->clock_high);
 229                         /* Do not reorder initial_high and high readings */
 230                         virt_rmb();
 231                         low = READ_ONCE(steal->clock_low);
 232                         /* Keep low reading in between */
 233                         virt_rmb();
 234                         high = READ_ONCE(steal->clock_high);
 235                 } while (initial_high != high);
 236
 237                 clock = ((uint64_t)high << 32) | low;
 238         }
 239
 240         return mul_u64_u32_shr(clock, vmware_cyc2ns.cyc2ns_mul,
 241                              vmware_cyc2ns.cyc2ns_shift);
 242 }
 243
 244 static void vmware_register_steal_time(void)
 245 {
 246         int cpu = smp_processor_id();
 247         struct vmware_steal_time *st = &per_cpu(vmw_steal_time, cpu);
 248
 249         if (!has_steal_clock)
 250                 return;
 251
 252         if (!stealclock_enable(slow_virt_to_phys(st))) {
 253                 has_steal_clock = false;
 254                 return;
 255         }
 256
 257         pr_info("vmware-stealtime: cpu %d, pa %llx\n",
 258                 cpu, (unsigned long long) slow_virt_to_phys(st));
 259 }
 260
 261 static void vmware_disable_steal_time(void)
 262 {
 263         if (!has_steal_clock)
 264                 return;
 265
 266         stealclock_disable();
 267 }
 268
 269 static void vmware_guest_cpu_init(void)
 270 {
 271         if (has_steal_clock)
 272                 vmware_register_steal_time();
 273 }
 274
 275 static void vmware_pv_guest_cpu_reboot(void *unused)
 276 {
 277         vmware_disable_steal_time();
 278 }
 279
 280 static int vmware_pv_reboot_notify(struct notifier_block *nb,
 281                                 unsigned long code, void *unused)
 282 {
 283         if (code == SYS_RESTART)
 284                 on_each_cpu(vmware_pv_guest_cpu_reboot, NULL, 1);
 285         return NOTIFY_DONE;
 286 }
 287
 288 static struct notifier_block vmware_pv_reboot_nb = {
 289         .notifier_call = vmware_pv_reboot_notify,
 290 };
 291
 292 #ifdef CONFIG_SMP
 293 static void __init vmware_smp_prepare_boot_cpu(void)
 294 {
 295         vmware_guest_cpu_init();
 296         native_smp_prepare_boot_cpu();
 297 }
 298
 299 static int vmware_cpu_online(unsigned int cpu)
 300 {
 301         local_irq_disable();
 302         vmware_guest_cpu_init();
 303         local_irq_enable();
 304         return 0;
 305 }
 306
 307 static int vmware_cpu_down_prepare(unsigned int cpu)
 308 {
 309         local_irq_disable();
 310         vmware_disable_steal_time();
 311         local_irq_enable();
 312         return 0;
 313 }
 314 #endif
 315
 316 static __init int activate_jump_labels(void)
 317 {
 318         if (has_steal_clock) {
 319                 static_key_slow_inc(&paravirt_steal_enabled);
 320                 if (steal_acc)
 321                         static_key_slow_inc(&paravirt_steal_rq_enabled);
 322         }
 323
 324         return 0;
 325 }
 326 arch_initcall(activate_jump_labels);
 327
 328 static void __init vmware_paravirt_ops_setup(void)
 329 {
 330         pv_info.name = "VMware hypervisor";
 331         pv_ops.cpu.io_delay = paravirt_nop;
 332
 333         if (vmware_tsc_khz == 0)
 334                 return;
 335
 336         vmware_cyc2ns_setup();
 337
 338         if (vmw_sched_clock)
 339                 pv_ops.time.sched_clock = vmware_sched_clock;
 340
 341         if (vmware_is_stealclock_available()) {
 342                 has_steal_clock = true;
 343                 pv_ops.time.steal_clock = vmware_steal_clock;
 344
 345                 /* We use reboot notifier only to disable steal clock */
 346                 register_reboot_notifier(&vmware_pv_reboot_nb);
 347
 348 #ifdef CONFIG_SMP
 349                 smp_ops.smp_prepare_boot_cpu =
 350                         vmware_smp_prepare_boot_cpu;
 351                 if (cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
 352                                               "x86/vmware:online",
 353                                               vmware_cpu_online,
 354                                               vmware_cpu_down_prepare) < 0)
 355                         pr_err("vmware_guest: Failed to install cpu hotplug callbacks\n");
 356 #else
 357                 vmware_guest_cpu_init();
 358 #endif
 359         }
 360 }
 361 #else
 362 #define vmware_paravirt_ops_setup() do {} while (0)
 363 #endif
 364
 365 /*
 366  * VMware hypervisor takes care of exporting a reliable TSC to the guest.
 367  * Still, due to timing difference when running on virtual cpus, the TSC can
 368  * be marked as unstable in some cases. For example, the TSC sync check at
 369  * bootup can fail due to a marginal offset between vcpus' TSCs (though the
 370  * TSCs do not drift from each other).  Also, the ACPI PM timer clocksource
 371  * is not suitable as a watchdog when running on a hypervisor because the
 372  * kernel may miss a wrap of the counter if the vcpu is descheduled for a
 373  * long time. To skip these checks at runtime we set these capability bits,
 374  * so that the kernel could just trust the hypervisor with providing a
 375  * reliable virtual TSC that is suitable for timekeeping.
 376  */
 377 static void __init vmware_set_capabilities(void)
 378 {
 379         setup_force_cpu_cap(X86_FEATURE_CONSTANT_TSC);
 380         setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
 381         if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMCALL)
 382                 setup_force_cpu_cap(X86_FEATURE_VMCALL);
 383         else if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMMCALL)
 384                 setup_force_cpu_cap(X86_FEATURE_VMW_VMMCALL);
 385 }
 386
 387 static void __init vmware_platform_setup(void)
 388 {
 389         uint32_t eax, ebx, ecx, edx;
 390         uint64_t lpj, tsc_khz;
 391
 392         VMWARE_CMD(GETHZ, eax, ebx, ecx, edx);
 393
 394         if (ebx != UINT_MAX) {
 395                 lpj = tsc_khz = eax | (((uint64_t)ebx) << 32);
 396                 do_div(tsc_khz, 1000);
 397                 WARN_ON(tsc_khz >> 32);
 398                 pr_info("TSC freq read from hypervisor : %lu.%03lu MHz\n",
 399                         (unsigned long) tsc_khz / 1000,
 400                         (unsigned long) tsc_khz % 1000);
 401
 402                 if (!preset_lpj) {
 403                         do_div(lpj, HZ);
 404                         preset_lpj = lpj;
 405                 }
 406
 407                 vmware_tsc_khz = tsc_khz;
 408                 x86_platform.calibrate_tsc = vmware_get_tsc_khz;
 409                 x86_platform.calibrate_cpu = vmware_get_tsc_khz;
 410
 411 #ifdef CONFIG_X86_LOCAL_APIC
 412                 /* Skip lapic calibration since we know the bus frequency. */
 413                 lapic_timer_period = ecx / HZ;
 414                 pr_info("Host bus clock speed read from hypervisor : %u Hz\n",
 415                         ecx);
 416 #endif
 417         } else {
 418                 pr_warn("Failed to get TSC freq from the hypervisor\n");
 419         }
 420
 421         vmware_paravirt_ops_setup();
 422
 423 #ifdef CONFIG_X86_IO_APIC
 424         no_timer_check = 1;
 425 #endif
 426
 427         vmware_set_capabilities();
 428 }
 429
 430 static u8 __init vmware_select_hypercall(void)
 431 {
 432         int eax, ebx, ecx, edx;
 433
 434         cpuid(CPUID_VMWARE_FEATURES_LEAF, &eax, &ebx, &ecx, &edx);
 435         return (ecx & (CPUID_VMWARE_FEATURES_ECX_VMMCALL |
 436                        CPUID_VMWARE_FEATURES_ECX_VMCALL));
 437 }
 438
 439 /*
 440  * While checking the dmi string information, just checking the product
 441  * serial key should be enough, as this will always have a VMware
 442  * specific string when running under VMware hypervisor.
 443  * If !boot_cpu_has(X86_FEATURE_HYPERVISOR), vmware_hypercall_mode
 444  * intentionally defaults to 0.
 445  */
 446 static uint32_t __init vmware_platform(void)
 447 {
 448         if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
 449                 unsigned int eax;
 450                 unsigned int hyper_vendor_id[3];
 451
 452                 cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0],
 453                       &hyper_vendor_id[1], &hyper_vendor_id[2]);
 454                 if (!memcmp(hyper_vendor_id, "VMwareVMware", 12)) {
 455                         if (eax >= CPUID_VMWARE_FEATURES_LEAF)
 456                                 vmware_hypercall_mode =
 457                                         vmware_select_hypercall();
 458
 459                         pr_info("hypercall mode: 0x%02x\n",
 460                                 (unsigned int) vmware_hypercall_mode);
 461
 462                         return CPUID_VMWARE_INFO_LEAF;
 463                 }
 464         } else if (dmi_available && dmi_name_in_serial("VMware") &&
 465                    __vmware_platform())
 466                 return 1;
 467
 468         return 0;
 469 }
 470
 471 /* Checks if hypervisor supports x2apic without VT-D interrupt remapping. */
 472 static bool __init vmware_legacy_x2apic_available(void)
 473 {
 474         uint32_t eax, ebx, ecx, edx;
 475         VMWARE_CMD(GETVCPU_INFO, eax, ebx, ecx, edx);
 476         return (eax & (1 << VMWARE_CMD_VCPU_RESERVED)) == 0 &&
 477                (eax & (1 << VMWARE_CMD_LEGACY_X2APIC)) != 0;
 478 }
 479
 480 #ifdef CONFIG_AMD_MEM_ENCRYPT
 481 static void vmware_sev_es_hcall_prepare(struct ghcb *ghcb,
 482                                         struct pt_regs *regs)
 483 {
 484         /* Copy VMWARE specific Hypercall parameters to the GHCB */
 485         ghcb_set_rip(ghcb, regs->ip);
 486         ghcb_set_rbx(ghcb, regs->bx);
 487         ghcb_set_rcx(ghcb, regs->cx);
 488         ghcb_set_rdx(ghcb, regs->dx);
 489         ghcb_set_rsi(ghcb, regs->si);
 490         ghcb_set_rdi(ghcb, regs->di);
 491         ghcb_set_rbp(ghcb, regs->bp);
 492 }
 493
 494 static bool vmware_sev_es_hcall_finish(struct ghcb *ghcb, struct pt_regs *regs)
 495 {
 496         if (!(ghcb_rbx_is_valid(ghcb) &&
 497               ghcb_rcx_is_valid(ghcb) &&
 498               ghcb_rdx_is_valid(ghcb) &&
 499               ghcb_rsi_is_valid(ghcb) &&
 500               ghcb_rdi_is_valid(ghcb) &&
 501               ghcb_rbp_is_valid(ghcb)))
 502                 return false;
 503
 504         regs->bx = ghcb->save.rbx;
 505         regs->cx = ghcb->save.rcx;
 506         regs->dx = ghcb->save.rdx;
 507         regs->si = ghcb->save.rsi;
 508         regs->di = ghcb->save.rdi;
 509         regs->bp = ghcb->save.rbp;
 510
 511         return true;
 512 }
 513 #endif
 514
 515 const __initconst struct hypervisor_x86 x86_hyper_vmware = {
 516         .name                           = "VMware",
 517         .detect                         = vmware_platform,
 518         .type                           = X86_HYPER_VMWARE,
 519         .init.init_platform             = vmware_platform_setup,
 520         .init.x2apic_available          = vmware_legacy_x2apic_available,
 521 #ifdef CONFIG_AMD_MEM_ENCRYPT
 522         .runtime.sev_es_hcall_prepare   = vmware_sev_es_hcall_prepare,
 523         .runtime.sev_es_hcall_finish    = vmware_sev_es_hcall_finish,
 524 #endif
 525 };