blob: 4d2b6f515d0734e9c8091af01f3ecae296c84b9f [file] [log] [blame]
/*
* This program is derived from systemd.
*
* Copyright 2011 Lennart Poettering
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 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. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#define streq(a, b) (!strcmp(a, b))
#define ELEMENTSOF(a) (sizeof(a) / sizeof((a)[0]))
enum {
VIRTUALIZATION_NONE,
VIRTUALIZATION_VM_OTHER,
VIRTUALIZATION_MICROSOFT,
};
static int detect_vm_cpuid(void) {
static const struct {
const char *cpuid;
int id;
} cpuid_vendor_table[] = {
/* http://msdn.microsoft.com/en-us/library/ff542428.aspx */
{ "Microsoft Hv", VIRTUALIZATION_MICROSOFT },
};
uint32_t eax, ecx;
bool hypervisor;
/* http://lwn.net/Articles/301888/ */
#if defined (__i386__)
#define REG_a "eax"
#define REG_b "ebx"
#elif defined (__amd64__)
#define REG_a "rax"
#define REG_b "rbx"
#endif
/* First detect whether there is a hypervisor */
eax = 1;
__asm__ __volatile__ (
/* ebx/rbx is being used for PIC! */
" push %%"REG_b" \n\t"
" cpuid \n\t"
" pop %%"REG_b" \n\t"
: "=a" (eax), "=c" (ecx)
: "0" (eax)
);
hypervisor = !!(ecx & 0x80000000U);
if (hypervisor) {
union {
uint32_t sig32[3];
char text[13];
} sig = {};
unsigned j;
/* There is a hypervisor, see what it is */
eax = 0x40000000U;
__asm__ __volatile__ (
/* ebx/rbx is being used for PIC! */
" push %%"REG_b" \n\t"
" cpuid \n\t"
" mov %%ebx, %1 \n\t"
" pop %%"REG_b" \n\t"
: "=a" (eax), "=r" (sig.sig32[0]), "=c" (sig.sig32[1]), "=d" (sig.sig32[2])
: "0" (eax)
);
for (j = 0; j < ELEMENTSOF(cpuid_vendor_table); j ++)
if (streq(sig.text, cpuid_vendor_table[j].cpuid))
return cpuid_vendor_table[j].id;
return VIRTUALIZATION_VM_OTHER;
}
return VIRTUALIZATION_NONE;
}
int main(void)
{
return detect_vm_cpuid() != VIRTUALIZATION_MICROSOFT;
}