blob: 1cbed97b59cf841d8c41b4466ac040cf1c794b03 [file] [log] [blame]
* VMware Detection code.
* Copyright (C) 2008, VMware, Inc.
* Author : Alok N Kataria <>
* 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
* 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 <asm/div64.h>
#include <asm/vmware.h>
#include <asm/x86_init.h>
#define CPUID_VMWARE_INFO_LEAF 0x40000000
#define VMWARE_PORT(cmd, eax, ebx, ecx, edx) \
__asm__("inl (%%dx)" : \
"=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \
"1"(VMWARE_PORT_CMD_##cmd), \
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)
uint64_t tsc_hz;
uint32_t eax, ebx, ecx, edx;
VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
tsc_hz = eax | (((uint64_t)ebx) << 32);
do_div(tsc_hz, 1000);
BUG_ON(tsc_hz >> 32);
printk(KERN_INFO "TSC freq read from hypervisor : %lu.%03lu MHz\n",
(unsigned long) tsc_hz / 1000,
(unsigned long) tsc_hz % 1000);
return tsc_hz;
void __init vmware_platform_setup(void)
uint32_t eax, ebx, ecx, edx;
VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
if (ebx != UINT_MAX)
x86_platform.calibrate_tsc = vmware_get_tsc_khz;
"Failed to get TSC freq from the hypervisor\n");
* While checking the dmi string infomation, just checking the product
* serial key should be enough, as this will always have a VMware
* specific string when running under VMware hypervisor.
int vmware_platform(void)
if (cpu_has_hypervisor) {
unsigned int eax, ebx, ecx, edx;
char hyper_vendor_id[13];
cpuid(CPUID_VMWARE_INFO_LEAF, &eax, &ebx, &ecx, &edx);
memcpy(hyper_vendor_id + 0, &ebx, 4);
memcpy(hyper_vendor_id + 4, &ecx, 4);
memcpy(hyper_vendor_id + 8, &edx, 4);
hyper_vendor_id[12] = '\0';
if (!strcmp(hyper_vendor_id, "VMwareVMware"))
return 1;
} else if (dmi_available && dmi_name_in_serial("VMware") &&
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.
void __cpuinit vmware_set_feature_bits(struct cpuinfo_x86 *c)
set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
set_cpu_cap(c, X86_FEATURE_TSC_RELIABLE);