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(¶virt_steal_enabled); 321 if (steal_acc) 322 static_key_slow_inc(¶virt_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 & BIT(VMWARE_CMD_VCPU_RESERVED)) && 480 (eax & BIT(VMWARE_CMD_LEGACY_X2APIC)); 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 }; 529