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/module.h>
26#include <asm/div64.h>
27#include <asm/x86_init.h>
28#include <asm/hypervisor.h>
29
30#define CPUID_VMWARE_INFO_LEAF	0x40000000
31#define VMWARE_HYPERVISOR_MAGIC	0x564D5868
32#define VMWARE_HYPERVISOR_PORT	0x5658
33
34#define VMWARE_PORT_CMD_GETVERSION	10
35#define VMWARE_PORT_CMD_GETHZ		45
36#define VMWARE_PORT_CMD_GETVCPU_INFO	68
37#define VMWARE_PORT_CMD_LEGACY_X2APIC	3
38#define VMWARE_PORT_CMD_VCPU_RESERVED	31
39
40#define VMWARE_PORT(cmd, eax, ebx, ecx, edx)				\
41	__asm__("inl (%%dx)" :						\
42			"=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) :	\
43			"0"(VMWARE_HYPERVISOR_MAGIC),			\
44			"1"(VMWARE_PORT_CMD_##cmd),			\
45			"2"(VMWARE_HYPERVISOR_PORT), "3"(UINT_MAX) :	\
46			"memory");
47
48static inline int __vmware_platform(void)
49{
50	uint32_t eax, ebx, ecx, edx;
51	VMWARE_PORT(GETVERSION, eax, ebx, ecx, edx);
52	return eax != (uint32_t)-1 && ebx == VMWARE_HYPERVISOR_MAGIC;
53}
54
55static unsigned long vmware_get_tsc_khz(void)
56{
57	uint64_t tsc_hz, lpj;
58	uint32_t eax, ebx, ecx, edx;
59
60	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
61
62	tsc_hz = eax | (((uint64_t)ebx) << 32);
63	do_div(tsc_hz, 1000);
64	BUG_ON(tsc_hz >> 32);
65	printk(KERN_INFO "TSC freq read from hypervisor : %lu.%03lu MHz\n",
66			 (unsigned long) tsc_hz / 1000,
67			 (unsigned long) tsc_hz % 1000);
68
69	if (!preset_lpj) {
70		lpj = ((u64)tsc_hz * 1000);
71		do_div(lpj, HZ);
72		preset_lpj = lpj;
73	}
74
75	return tsc_hz;
76}
77
78static void __init vmware_platform_setup(void)
79{
80	uint32_t eax, ebx, ecx, edx;
81
82	VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
83
84	if (ebx != UINT_MAX)
85		x86_platform.calibrate_tsc = vmware_get_tsc_khz;
86	else
87		printk(KERN_WARNING
88		       "Failed to get TSC freq from the hypervisor\n");
89}
90
91/*
92 * While checking the dmi string information, just checking the product
93 * serial key should be enough, as this will always have a VMware
94 * specific string when running under VMware hypervisor.
95 */
96static uint32_t __init vmware_platform(void)
97{
98	if (cpu_has_hypervisor) {
99		unsigned int eax;
100		unsigned int hyper_vendor_id[3];
101
102		cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0],
103		      &hyper_vendor_id[1], &hyper_vendor_id[2]);
104		if (!memcmp(hyper_vendor_id, "VMwareVMware", 12))
105			return CPUID_VMWARE_INFO_LEAF;
106	} else if (dmi_available && dmi_name_in_serial("VMware") &&
107		   __vmware_platform())
108		return 1;
109
110	return 0;
111}
112
113/*
114 * VMware hypervisor takes care of exporting a reliable TSC to the guest.
115 * Still, due to timing difference when running on virtual cpus, the TSC can
116 * be marked as unstable in some cases. For example, the TSC sync check at
117 * bootup can fail due to a marginal offset between vcpus' TSCs (though the
118 * TSCs do not drift from each other).  Also, the ACPI PM timer clocksource
119 * is not suitable as a watchdog when running on a hypervisor because the
120 * kernel may miss a wrap of the counter if the vcpu is descheduled for a
121 * long time. To skip these checks at runtime we set these capability bits,
122 * so that the kernel could just trust the hypervisor with providing a
123 * reliable virtual TSC that is suitable for timekeeping.
124 */
125static void vmware_set_cpu_features(struct cpuinfo_x86 *c)
126{
127	set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
128	set_cpu_cap(c, X86_FEATURE_TSC_RELIABLE);
129}
130
131/* Checks if hypervisor supports x2apic without VT-D interrupt remapping. */
132static bool __init vmware_legacy_x2apic_available(void)
133{
134	uint32_t eax, ebx, ecx, edx;
135	VMWARE_PORT(GETVCPU_INFO, eax, ebx, ecx, edx);
136	return (eax & (1 << VMWARE_PORT_CMD_VCPU_RESERVED)) == 0 &&
137	       (eax & (1 << VMWARE_PORT_CMD_LEGACY_X2APIC)) != 0;
138}
139
140const __refconst struct hypervisor_x86 x86_hyper_vmware = {
141	.name			= "VMware",
142	.detect			= vmware_platform,
143	.set_cpu_features	= vmware_set_cpu_features,
144	.init_platform		= vmware_platform_setup,
145	.x2apic_available	= vmware_legacy_x2apic_available,
146};
147EXPORT_SYMBOL(x86_hyper_vmware);
148