summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/cpu/vmware.c
blob: 891f4dad7b2c49c81518e15ecee61bc8d4694ff2 (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
/*
 * 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 <asm/div64.h>
#include <asm/x86_init.h>
#include <asm/hypervisor.h>
#include <asm/timer.h>
#include <asm/apic.h>
#include <asm/timer.h>

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

#define CPUID_VMWARE_INFO_LEAF	0x40000000
#define VMWARE_HYPERVISOR_MAGIC	0x564D5868
#define VMWARE_HYPERVISOR_PORT	0x5658

#define VMWARE_PORT_CMD_GETVERSION	10
#define VMWARE_PORT_CMD_GETHZ		45
#define VMWARE_PORT_CMD_GETVCPU_INFO	68
#define VMWARE_PORT_CMD_LEGACY_X2APIC	3
#define VMWARE_PORT_CMD_VCPU_RESERVED	31

#define VMWARE_PORT(cmd, eax, ebx, ecx, edx)				\
	__asm__("inl (%%dx)" :						\
			"=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) :	\
			"0"(VMWARE_HYPERVISOR_MAGIC),			\
			"1"(VMWARE_PORT_CMD_##cmd),			\
			"2"(VMWARE_HYPERVISOR_PORT), "3"(UINT_MAX) :	\
			"memory");

static unsigned long vmware_tsc_khz __ro_after_init;

static inline int __vmware_platform(void)
{
	uint32_t eax, ebx, ecx, edx;
	VMWARE_PORT(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 int vmw_sched_clock __initdata = 1;

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

static unsigned long long 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_sched_clock_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);

	pv_time_ops.sched_clock = vmware_sched_clock;
	pr_info("using sched offset of %llu ns\n", d->cyc2ns_offset);
}

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

	if (vmware_tsc_khz && vmw_sched_clock)
		vmware_sched_clock_setup();
}
#else
#define vmware_paravirt_ops_setup() do {} while (0)
#endif

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

	VMWARE_PORT(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_frequency = 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
}

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

	return 0;
}

/*
 * 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 vmware_set_cpu_features(struct cpuinfo_x86 *c)
{
	set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
	set_cpu_cap(c, X86_FEATURE_TSC_RELIABLE);
}

/* 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_PORT(GETVCPU_INFO, eax, ebx, ecx, edx);
	return (eax & (1 << VMWARE_PORT_CMD_VCPU_RESERVED)) == 0 &&
	       (eax & (1 << VMWARE_PORT_CMD_LEGACY_X2APIC)) != 0;
}

const __refconst struct hypervisor_x86 x86_hyper_vmware = {
	.name			= "VMware",
	.detect			= vmware_platform,
	.set_cpu_features	= vmware_set_cpu_features,
	.init_platform		= vmware_platform_setup,
	.x2apic_available	= vmware_legacy_x2apic_available,
};
EXPORT_SYMBOL(x86_hyper_vmware);