summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/cpu/vmware.c
blob: c6ede3b3d302d3fb28222f0f398e5afb6a3ca336 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
/*
 * VMware Detection code.
 *
 * Copyright (C) 2008, VMware, Inc.
 * Author : Alok N Kataria <akataria@vmware.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */

#include <linux/dmi.h>
#include <linux/init.h>
#include <linux/export.h>
#include <linux/clocksource.h>
#include <linux/cpu.h>
#include <linux/reboot.h>
#include <asm/div64.h>
#include <asm/x86_init.h>
#include <asm/hypervisor.h>
#include <asm/timer.h>
#include <asm/apic.h>
#include <asm/vmware.h>
#include <asm/svm.h>

#undef pr_fmt
#define pr_fmt(fmt)	"vmware: " fmt

#define CPUID_VMWARE_INFO_LEAF               0x40000000
#define CPUID_VMWARE_FEATURES_LEAF           0x40000010
#define CPUID_VMWARE_FEATURES_ECX_VMMCALL    BIT(0)
#define CPUID_VMWARE_FEATURES_ECX_VMCALL     BIT(1)

#define VMWARE_HYPERVISOR_MAGIC	0x564D5868

#define VMWARE_CMD_GETVERSION    10
#define VMWARE_CMD_GETHZ         45
#define VMWARE_CMD_GETVCPU_INFO  68
#define VMWARE_CMD_LEGACY_X2APIC  3
#define VMWARE_CMD_VCPU_RESERVED 31
#define VMWARE_CMD_STEALCLOCK    91

#define STEALCLOCK_NOT_AVAILABLE (-1)
#define STEALCLOCK_DISABLED        0
#define STEALCLOCK_ENABLED         1

#define VMWARE_PORT(cmd, eax, ebx, ecx, edx)				\
	__asm__("inl (%%dx), %%eax" :					\
		"=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) :		\
		"a"(VMWARE_HYPERVISOR_MAGIC),				\
		"c"(VMWARE_CMD_##cmd),					\
		"d"(VMWARE_HYPERVISOR_PORT), "b"(UINT_MAX) :		\
		"memory")

#define VMWARE_VMCALL(cmd, eax, ebx, ecx, edx)				\
	__asm__("vmcall" :						\
		"=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) :		\
		"a"(VMWARE_HYPERVISOR_MAGIC),				\
		"c"(VMWARE_CMD_##cmd),					\
		"d"(0), "b"(UINT_MAX) :					\
		"memory")

#define VMWARE_VMMCALL(cmd, eax, ebx, ecx, edx)                         \
	__asm__("vmmcall" :						\
		"=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) :		\
		"a"(VMWARE_HYPERVISOR_MAGIC),				\
		"c"(VMWARE_CMD_##cmd),					\
		"d"(0), "b"(UINT_MAX) :					\
		"memory")

#define VMWARE_CMD(cmd, eax, ebx, ecx, edx) do {		\
	switch (vmware_hypercall_mode) {			\
	case CPUID_VMWARE_FEATURES_ECX_VMCALL:			\
		VMWARE_VMCALL(cmd, eax, ebx, ecx, edx);		\
		break;						\
	case CPUID_VMWARE_FEATURES_ECX_VMMCALL:			\
		VMWARE_VMMCALL(cmd, eax, ebx, ecx, edx);	\
		break;						\
	default:						\
		VMWARE_PORT(cmd, eax, ebx, ecx, edx);		\
		break;						\
	}							\
	} while (0)

struct vmware_steal_time {
	union {
		uint64_t clock;	/* stolen time counter in units of vtsc */
		struct {
			/* only for little-endian */
			uint32_t clock_low;
			uint32_t clock_high;
		};
	};
	uint64_t reserved[7];
};

static unsigned long vmware_tsc_khz __ro_after_init;
static u8 vmware_hypercall_mode     __ro_after_init;

static inline int __vmware_platform(void)
{
	uint32_t eax, ebx, ecx, edx;
	VMWARE_CMD(GETVERSION, eax, ebx, ecx, edx);
	return eax != (uint32_t)-1 && ebx == VMWARE_HYPERVISOR_MAGIC;
}

static unsigned long vmware_get_tsc_khz(void)
{
	return vmware_tsc_khz;
}

#ifdef CONFIG_PARAVIRT
static struct cyc2ns_data vmware_cyc2ns __ro_after_init;
static bool vmw_sched_clock __initdata = true;
static DEFINE_PER_CPU_DECRYPTED(struct vmware_steal_time, vmw_steal_time) __aligned(64);
static bool has_steal_clock;
static bool steal_acc __initdata = true; /* steal time accounting */

static __init int setup_vmw_sched_clock(char *s)
{
	vmw_sched_clock = false;
	return 0;
}
early_param("no-vmw-sched-clock", setup_vmw_sched_clock);

static __init int parse_no_stealacc(char *arg)
{
	steal_acc = false;
	return 0;
}
early_param("no-steal-acc", parse_no_stealacc);

static unsigned long long notrace vmware_sched_clock(void)
{
	unsigned long long ns;

	ns = mul_u64_u32_shr(rdtsc(), vmware_cyc2ns.cyc2ns_mul,
			     vmware_cyc2ns.cyc2ns_shift);
	ns -= vmware_cyc2ns.cyc2ns_offset;
	return ns;
}

static void __init vmware_cyc2ns_setup(void)
{
	struct cyc2ns_data *d = &vmware_cyc2ns;
	unsigned long long tsc_now = rdtsc();

	clocks_calc_mult_shift(&d->cyc2ns_mul, &d->cyc2ns_shift,
			       vmware_tsc_khz, NSEC_PER_MSEC, 0);
	d->cyc2ns_offset = mul_u64_u32_shr(tsc_now, d->cyc2ns_mul,
					   d->cyc2ns_shift);

	pr_info("using clock offset of %llu ns\n", d->cyc2ns_offset);
}

static int vmware_cmd_stealclock(uint32_t arg1, uint32_t arg2)
{
	uint32_t result, info;

	asm volatile (VMWARE_HYPERCALL :
		"=a"(result),
		"=c"(info) :
		"a"(VMWARE_HYPERVISOR_MAGIC),
		"b"(0),
		"c"(VMWARE_CMD_STEALCLOCK),
		"d"(0),
		"S"(arg1),
		"D"(arg2) :
		"memory");
	return result;
}

static bool stealclock_enable(phys_addr_t pa)
{
	return vmware_cmd_stealclock(upper_32_bits(pa),
				     lower_32_bits(pa)) == STEALCLOCK_ENABLED;
}

static int __stealclock_disable(void)
{
	return vmware_cmd_stealclock(0, 1);
}

static void stealclock_disable(void)
{
	__stealclock_disable();
}

static bool vmware_is_stealclock_available(void)
{
	return __stealclock_disable() != STEALCLOCK_NOT_AVAILABLE;
}

/**
 * vmware_steal_clock() - read the per-cpu steal clock
 * @cpu:            the cpu number whose steal clock we want to read
 *
 * The function reads the steal clock if we are on a 64-bit system, otherwise
 * reads it in parts, checking that the high part didn't change in the
 * meantime.
 *
 * Return:
 *      The steal clock reading in ns.
 */
static uint64_t vmware_steal_clock(int cpu)
{
	struct vmware_steal_time *steal = &per_cpu(vmw_steal_time, cpu);
	uint64_t clock;

	if (IS_ENABLED(CONFIG_64BIT))
		clock = READ_ONCE(steal->clock);
	else {
		uint32_t initial_high, low, high;

		do {
			initial_high = READ_ONCE(steal->clock_high);
			/* Do not reorder initial_high and high readings */
			virt_rmb();
			low = READ_ONCE(steal->clock_low);
			/* Keep low reading in between */
			virt_rmb();
			high = READ_ONCE(steal->clock_high);
		} while (initial_high != high);

		clock = ((uint64_t)high << 32) | low;
	}

	return mul_u64_u32_shr(clock, vmware_cyc2ns.cyc2ns_mul,
			     vmware_cyc2ns.cyc2ns_shift);
}

static void vmware_register_steal_time(void)
{
	int cpu = smp_processor_id();
	struct vmware_steal_time *st = &per_cpu(vmw_steal_time, cpu);

	if (!has_steal_clock)
		return;

	if (!stealclock_enable(slow_virt_to_phys(st))) {
		has_steal_clock = false;
		return;
	}

	pr_info("vmware-stealtime: cpu %d, pa %llx\n",
		cpu, (unsigned long long) slow_virt_to_phys(st));
}

static void vmware_disable_steal_time(void)
{
	if (!has_steal_clock)
		return;

	stealclock_disable();
}

static void vmware_guest_cpu_init(void)
{
	if (has_steal_clock)
		vmware_register_steal_time();
}

static void vmware_pv_guest_cpu_reboot(void *unused)
{
	vmware_disable_steal_time();
}

static int vmware_pv_reboot_notify(struct notifier_block *nb,
				unsigned long code, void *unused)
{
	if (code == SYS_RESTART)
		on_each_cpu(vmware_pv_guest_cpu_reboot, NULL, 1);
	return NOTIFY_DONE;
}

static struct notifier_block vmware_pv_reboot_nb = {
	.notifier_call = vmware_pv_reboot_notify,
};

#ifdef CONFIG_SMP
static void __init vmware_smp_prepare_boot_cpu(void)
{
	vmware_guest_cpu_init();
	native_smp_prepare_boot_cpu();
}

static int vmware_cpu_online(unsigned int cpu)
{
	local_irq_disable();
	vmware_guest_cpu_init();
	local_irq_enable();
	return 0;
}

static int vmware_cpu_down_prepare(unsigned int cpu)
{
	local_irq_disable();
	vmware_disable_steal_time();
	local_irq_enable();
	return 0;
}
#endif

static __init int activate_jump_labels(void)
{
	if (has_steal_clock) {
		static_key_slow_inc(&paravirt_steal_enabled);
		if (steal_acc)
			static_key_slow_inc(&paravirt_steal_rq_enabled);
	}

	return 0;
}
arch_initcall(activate_jump_labels);

static void __init vmware_paravirt_ops_setup(void)
{
	pv_info.name = "VMware hypervisor";
	pv_ops.cpu.io_delay = paravirt_nop;

	if (vmware_tsc_khz == 0)
		return;

	vmware_cyc2ns_setup();

	if (vmw_sched_clock)
		pv_ops.time.sched_clock = vmware_sched_clock;

	if (vmware_is_stealclock_available()) {
		has_steal_clock = true;
		pv_ops.time.steal_clock = vmware_steal_clock;

		/* We use reboot notifier only to disable steal clock */
		register_reboot_notifier(&vmware_pv_reboot_nb);

#ifdef CONFIG_SMP
		smp_ops.smp_prepare_boot_cpu =
			vmware_smp_prepare_boot_cpu;
		if (cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
					      "x86/vmware:online",
					      vmware_cpu_online,
					      vmware_cpu_down_prepare) < 0)
			pr_err("vmware_guest: Failed to install cpu hotplug callbacks\n");
#else
		vmware_guest_cpu_init();
#endif
	}
}
#else
#define vmware_paravirt_ops_setup() do {} while (0)
#endif

/*
 * VMware hypervisor takes care of exporting a reliable TSC to the guest.
 * Still, due to timing difference when running on virtual cpus, the TSC can
 * be marked as unstable in some cases. For example, the TSC sync check at
 * bootup can fail due to a marginal offset between vcpus' TSCs (though the
 * TSCs do not drift from each other).  Also, the ACPI PM timer clocksource
 * is not suitable as a watchdog when running on a hypervisor because the
 * kernel may miss a wrap of the counter if the vcpu is descheduled for a
 * long time. To skip these checks at runtime we set these capability bits,
 * so that the kernel could just trust the hypervisor with providing a
 * reliable virtual TSC that is suitable for timekeeping.
 */
static void __init vmware_set_capabilities(void)
{
	setup_force_cpu_cap(X86_FEATURE_CONSTANT_TSC);
	setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
	if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMCALL)
		setup_force_cpu_cap(X86_FEATURE_VMCALL);
	else if (vmware_hypercall_mode == CPUID_VMWARE_FEATURES_ECX_VMMCALL)
		setup_force_cpu_cap(X86_FEATURE_VMW_VMMCALL);
}

static void __init vmware_platform_setup(void)
{
	uint32_t eax, ebx, ecx, edx;
	uint64_t lpj, tsc_khz;

	VMWARE_CMD(GETHZ, eax, ebx, ecx, edx);

	if (ebx != UINT_MAX) {
		lpj = tsc_khz = eax | (((uint64_t)ebx) << 32);
		do_div(tsc_khz, 1000);
		WARN_ON(tsc_khz >> 32);
		pr_info("TSC freq read from hypervisor : %lu.%03lu MHz\n",
			(unsigned long) tsc_khz / 1000,
			(unsigned long) tsc_khz % 1000);

		if (!preset_lpj) {
			do_div(lpj, HZ);
			preset_lpj = lpj;
		}

		vmware_tsc_khz = tsc_khz;
		x86_platform.calibrate_tsc = vmware_get_tsc_khz;
		x86_platform.calibrate_cpu = vmware_get_tsc_khz;

#ifdef CONFIG_X86_LOCAL_APIC
		/* Skip lapic calibration since we know the bus frequency. */
		lapic_timer_period = ecx / HZ;
		pr_info("Host bus clock speed read from hypervisor : %u Hz\n",
			ecx);
#endif
	} else {
		pr_warn("Failed to get TSC freq from the hypervisor\n");
	}

	vmware_paravirt_ops_setup();

#ifdef CONFIG_X86_IO_APIC
	no_timer_check = 1;
#endif

	vmware_set_capabilities();
}

static u8 __init vmware_select_hypercall(void)
{
	int eax, ebx, ecx, edx;

	cpuid(CPUID_VMWARE_FEATURES_LEAF, &eax, &ebx, &ecx, &edx);
	return (ecx & (CPUID_VMWARE_FEATURES_ECX_VMMCALL |
		       CPUID_VMWARE_FEATURES_ECX_VMCALL));
}

/*
 * While checking the dmi string information, just checking the product
 * serial key should be enough, as this will always have a VMware
 * specific string when running under VMware hypervisor.
 * If !boot_cpu_has(X86_FEATURE_HYPERVISOR), vmware_hypercall_mode
 * intentionally defaults to 0.
 */
static uint32_t __init vmware_platform(void)
{
	if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
		unsigned int eax;
		unsigned int hyper_vendor_id[3];

		cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0],
		      &hyper_vendor_id[1], &hyper_vendor_id[2]);
		if (!memcmp(hyper_vendor_id, "VMwareVMware", 12)) {
			if (eax >= CPUID_VMWARE_FEATURES_LEAF)
				vmware_hypercall_mode =
					vmware_select_hypercall();

			pr_info("hypercall mode: 0x%02x\n",
				(unsigned int) vmware_hypercall_mode);

			return CPUID_VMWARE_INFO_LEAF;
		}
	} else if (dmi_available && dmi_name_in_serial("VMware") &&
		   __vmware_platform())
		return 1;

	return 0;
}

/* Checks if hypervisor supports x2apic without VT-D interrupt remapping. */
static bool __init vmware_legacy_x2apic_available(void)
{
	uint32_t eax, ebx, ecx, edx;
	VMWARE_CMD(GETVCPU_INFO, eax, ebx, ecx, edx);
	return (eax & (1 << VMWARE_CMD_VCPU_RESERVED)) == 0 &&
	       (eax & (1 << VMWARE_CMD_LEGACY_X2APIC)) != 0;
}

#ifdef CONFIG_AMD_MEM_ENCRYPT
static void vmware_sev_es_hcall_prepare(struct ghcb *ghcb,
					struct pt_regs *regs)
{
	/* Copy VMWARE specific Hypercall parameters to the GHCB */
	ghcb_set_rip(ghcb, regs->ip);
	ghcb_set_rbx(ghcb, regs->bx);
	ghcb_set_rcx(ghcb, regs->cx);
	ghcb_set_rdx(ghcb, regs->dx);
	ghcb_set_rsi(ghcb, regs->si);
	ghcb_set_rdi(ghcb, regs->di);
	ghcb_set_rbp(ghcb, regs->bp);
}

static bool vmware_sev_es_hcall_finish(struct ghcb *ghcb, struct pt_regs *regs)
{
	if (!(ghcb_rbx_is_valid(ghcb) &&
	      ghcb_rcx_is_valid(ghcb) &&
	      ghcb_rdx_is_valid(ghcb) &&
	      ghcb_rsi_is_valid(ghcb) &&
	      ghcb_rdi_is_valid(ghcb) &&
	      ghcb_rbp_is_valid(ghcb)))
		return false;

	regs->bx = ghcb_get_rbx(ghcb);
	regs->cx = ghcb_get_rcx(ghcb);
	regs->dx = ghcb_get_rdx(ghcb);
	regs->si = ghcb_get_rsi(ghcb);
	regs->di = ghcb_get_rdi(ghcb);
	regs->bp = ghcb_get_rbp(ghcb);

	return true;
}
#endif

const __initconst struct hypervisor_x86 x86_hyper_vmware = {
	.name				= "VMware",
	.detect				= vmware_platform,
	.type				= X86_HYPER_VMWARE,
	.init.init_platform		= vmware_platform_setup,
	.init.x2apic_available		= vmware_legacy_x2apic_available,
#ifdef CONFIG_AMD_MEM_ENCRYPT
	.runtime.sev_es_hcall_prepare	= vmware_sev_es_hcall_prepare,
	.runtime.sev_es_hcall_finish	= vmware_sev_es_hcall_finish,
#endif
};