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
__vmware_platform(void)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
vmware_get_tsc_khz(void)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
setup_vmw_sched_clock(char * s)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
parse_no_stealacc(char * arg)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
vmware_sched_clock(void)146 static noinstr u64 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
vmware_cyc2ns_setup(void)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
vmware_cmd_stealclock(uint32_t arg1,uint32_t arg2)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
stealclock_enable(phys_addr_t pa)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
__stealclock_disable(void)192 static int __stealclock_disable(void)
193 {
194 return vmware_cmd_stealclock(0, 1);
195 }
196
stealclock_disable(void)197 static void stealclock_disable(void)
198 {
199 __stealclock_disable();
200 }
201
vmware_is_stealclock_available(void)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 */
vmware_steal_clock(int cpu)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
vmware_register_steal_time(void)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
vmware_disable_steal_time(void)262 static void vmware_disable_steal_time(void)
263 {
264 if (!has_steal_clock)
265 return;
266
267 stealclock_disable();
268 }
269
vmware_guest_cpu_init(void)270 static void vmware_guest_cpu_init(void)
271 {
272 if (has_steal_clock)
273 vmware_register_steal_time();
274 }
275
vmware_pv_guest_cpu_reboot(void * unused)276 static void vmware_pv_guest_cpu_reboot(void *unused)
277 {
278 vmware_disable_steal_time();
279 }
280
vmware_pv_reboot_notify(struct notifier_block * nb,unsigned long code,void * unused)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
vmware_smp_prepare_boot_cpu(void)294 static void __init vmware_smp_prepare_boot_cpu(void)
295 {
296 vmware_guest_cpu_init();
297 native_smp_prepare_boot_cpu();
298 }
299
vmware_cpu_online(unsigned int cpu)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
vmware_cpu_down_prepare(unsigned int cpu)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
activate_jump_labels(void)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
vmware_paravirt_ops_setup(void)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 */
vmware_set_capabilities(void)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
vmware_platform_setup(void)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
vmware_select_hypercall(void)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 */
vmware_platform(void)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. */
vmware_legacy_x2apic_available(void)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
vmware_sev_es_hcall_prepare(struct ghcb * ghcb,struct pt_regs * regs)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
vmware_sev_es_hcall_finish(struct ghcb * ghcb,struct pt_regs * regs)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
