2 * VMware Detection code.
4 * Copyright (C) 2008, VMware, Inc.
5 * Author : Alok N Kataria <akataria@vmware.com>
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.
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
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.
24 #include <linux/dmi.h>
25 #include <linux/init.h>
26 #include <linux/export.h>
27 #include <asm/div64.h>
28 #include <asm/x86_init.h>
29 #include <asm/hypervisor.h>
32 #define CPUID_VMWARE_INFO_LEAF 0x40000000
33 #define VMWARE_HYPERVISOR_MAGIC 0x564D5868
34 #define VMWARE_HYPERVISOR_PORT 0x5658
36 #define VMWARE_PORT_CMD_GETVERSION 10
37 #define VMWARE_PORT_CMD_GETHZ 45
38 #define VMWARE_PORT_CMD_GETVCPU_INFO 68
39 #define VMWARE_PORT_CMD_LEGACY_X2APIC 3
40 #define VMWARE_PORT_CMD_VCPU_RESERVED 31
42 #define VMWARE_PORT(cmd, eax, ebx, ecx, edx) \
43 __asm__("inl (%%dx)" : \
44 "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \
45 "0"(VMWARE_HYPERVISOR_MAGIC), \
46 "1"(VMWARE_PORT_CMD_##cmd), \
47 "2"(VMWARE_HYPERVISOR_PORT), "3"(UINT_MAX) : \
50 static inline int __vmware_platform(void)
52 uint32_t eax, ebx, ecx, edx;
53 VMWARE_PORT(GETVERSION, eax, ebx, ecx, edx);
54 return eax != (uint32_t)-1 && ebx == VMWARE_HYPERVISOR_MAGIC;
57 static unsigned long vmware_get_tsc_khz(void)
60 uint32_t eax, ebx, ecx, edx;
62 VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
64 tsc_hz = eax | (((uint64_t)ebx) << 32);
67 pr_info("TSC freq read from hypervisor : %lu.%03lu MHz\n",
68 (unsigned long) tsc_hz / 1000,
69 (unsigned long) tsc_hz % 1000);
72 lpj = ((u64)tsc_hz * 1000);
80 static void __init vmware_platform_setup(void)
82 uint32_t eax, ebx, ecx, edx;
84 VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
86 if (ebx != UINT_MAX) {
87 x86_platform.calibrate_tsc = vmware_get_tsc_khz;
88 #ifdef CONFIG_X86_LOCAL_APIC
89 /* Skip lapic calibration since we know the bus frequency. */
90 lapic_timer_frequency = ecx / HZ;
91 pr_info("Host bus clock speed read from hypervisor : %u Hz\n",
95 pr_warn("Failed to get TSC freq from the hypervisor\n");
100 * While checking the dmi string information, just checking the product
101 * serial key should be enough, as this will always have a VMware
102 * specific string when running under VMware hypervisor.
104 static uint32_t __init vmware_platform(void)
106 if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
108 unsigned int hyper_vendor_id[3];
110 cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &hyper_vendor_id[0],
111 &hyper_vendor_id[1], &hyper_vendor_id[2]);
112 if (!memcmp(hyper_vendor_id, "VMwareVMware", 12))
113 return CPUID_VMWARE_INFO_LEAF;
114 } else if (dmi_available && dmi_name_in_serial("VMware") &&
122 * VMware hypervisor takes care of exporting a reliable TSC to the guest.
123 * Still, due to timing difference when running on virtual cpus, the TSC can
124 * be marked as unstable in some cases. For example, the TSC sync check at
125 * bootup can fail due to a marginal offset between vcpus' TSCs (though the
126 * TSCs do not drift from each other). Also, the ACPI PM timer clocksource
127 * is not suitable as a watchdog when running on a hypervisor because the
128 * kernel may miss a wrap of the counter if the vcpu is descheduled for a
129 * long time. To skip these checks at runtime we set these capability bits,
130 * so that the kernel could just trust the hypervisor with providing a
131 * reliable virtual TSC that is suitable for timekeeping.
133 static void vmware_set_cpu_features(struct cpuinfo_x86 *c)
135 set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
136 set_cpu_cap(c, X86_FEATURE_TSC_RELIABLE);
139 /* Checks if hypervisor supports x2apic without VT-D interrupt remapping. */
140 static bool __init vmware_legacy_x2apic_available(void)
142 uint32_t eax, ebx, ecx, edx;
143 VMWARE_PORT(GETVCPU_INFO, eax, ebx, ecx, edx);
144 return (eax & (1 << VMWARE_PORT_CMD_VCPU_RESERVED)) == 0 &&
145 (eax & (1 << VMWARE_PORT_CMD_LEGACY_X2APIC)) != 0;
148 const __refconst struct hypervisor_x86 x86_hyper_vmware = {
150 .detect = vmware_platform,
151 .set_cpu_features = vmware_set_cpu_features,
152 .init_platform = vmware_platform_setup,
153 .x2apic_available = vmware_legacy_x2apic_available,
155 EXPORT_SYMBOL(x86_hyper_vmware);