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-rw-r--r--arch/x86/kernel/cpu/vmware.c112
1 files changed, 112 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
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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 <asm/div64.h>
26#include <asm/vmware.h>
27
28#define CPUID_VMWARE_INFO_LEAF 0x40000000
29#define VMWARE_HYPERVISOR_MAGIC 0x564D5868
30#define VMWARE_HYPERVISOR_PORT 0x5658
31
32#define VMWARE_PORT_CMD_GETVERSION 10
33#define VMWARE_PORT_CMD_GETHZ 45
34
35#define VMWARE_PORT(cmd, eax, ebx, ecx, edx) \
36 __asm__("inl (%%dx)" : \
37 "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \
38 "0"(VMWARE_HYPERVISOR_MAGIC), \
39 "1"(VMWARE_PORT_CMD_##cmd), \
40 "2"(VMWARE_HYPERVISOR_PORT), "3"(UINT_MAX) : \
41 "memory");
42
43static inline int __vmware_platform(void)
44{
45 uint32_t eax, ebx, ecx, edx;
46 VMWARE_PORT(GETVERSION, eax, ebx, ecx, edx);
47 return eax != (uint32_t)-1 && ebx == VMWARE_HYPERVISOR_MAGIC;
48}
49
50static unsigned long __vmware_get_tsc_khz(void)
51{
52 uint64_t tsc_hz;
53 uint32_t eax, ebx, ecx, edx;
54
55 VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
56
57 if (ebx == UINT_MAX)
58 return 0;
59 tsc_hz = eax | (((uint64_t)ebx) << 32);
60 do_div(tsc_hz, 1000);
61 BUG_ON(tsc_hz >> 32);
62 return tsc_hz;
63}
64
65/*
66 * While checking the dmi string infomation, just checking the product
67 * serial key should be enough, as this will always have a VMware
68 * specific string when running under VMware hypervisor.
69 */
70int vmware_platform(void)
71{
72 if (cpu_has_hypervisor) {
73 unsigned int eax, ebx, ecx, edx;
74 char hyper_vendor_id[13];
75
76 cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &ebx, &ecx, &edx);
77 memcpy(hyper_vendor_id + 0, &ebx, 4);
78 memcpy(hyper_vendor_id + 4, &ecx, 4);
79 memcpy(hyper_vendor_id + 8, &edx, 4);
80 hyper_vendor_id[12] = '\0';
81 if (!strcmp(hyper_vendor_id, "VMwareVMware"))
82 return 1;
83 } else if (dmi_available && dmi_name_in_serial("VMware") &&
84 __vmware_platform())
85 return 1;
86
87 return 0;
88}
89
90unsigned long vmware_get_tsc_khz(void)
91{
92 BUG_ON(!vmware_platform());
93 return __vmware_get_tsc_khz();
94}
95
96/*
97 * VMware hypervisor takes care of exporting a reliable TSC to the guest.
98 * Still, due to timing difference when running on virtual cpus, the TSC can
99 * be marked as unstable in some cases. For example, the TSC sync check at
100 * bootup can fail due to a marginal offset between vcpus' TSCs (though the
101 * TSCs do not drift from each other). Also, the ACPI PM timer clocksource
102 * is not suitable as a watchdog when running on a hypervisor because the
103 * kernel may miss a wrap of the counter if the vcpu is descheduled for a
104 * long time. To skip these checks at runtime we set these capability bits,
105 * so that the kernel could just trust the hypervisor with providing a
106 * reliable virtual TSC that is suitable for timekeeping.
107 */
108void __cpuinit vmware_set_feature_bits(struct cpuinfo_x86 *c)
109{
110 set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
111 set_cpu_cap(c, X86_FEATURE_TSC_RELIABLE);
112}