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virtualization: check cpuid first, since it is cheaper than DMI

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This commit is contained in:
Lennart Poettering 2011-02-22 01:39:19 +01:00
parent 4e08da90d4
commit 721bca5763
1 changed files with 55 additions and 50 deletions
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105
src/util.c
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@ -3713,7 +3713,7 @@ int detect_vm(const char **id) {
/* Both CPUID and DMI are x86 specific interfaces... */
const char *const dmi_vendors[] = {
static const char *const dmi_vendors[] = {
"/sys/class/dmi/id/sys_vendor",
"/sys/class/dmi/id/board_vendor",
"/sys/class/dmi/id/bios_vendor"
@ -3727,6 +3727,7 @@ int detect_vm(const char **id) {
"Microsoft Corporation\0" "microsoft\0"
"innotek GmbH\0" "oracle\0"
"Xen\0" "xen\0"
"Bochs\0" "bochs\0"
"\0";
static const char cpuid_vendor_table[] =
@ -3743,9 +3744,59 @@ int detect_vm(const char **id) {
uint32_t sig32[3];
char text[13];
} sig;
unsigned i;
const char *j, *k;
bool hypervisor;
/* http://lwn.net/Articles/301888/ */
zero(sig);
#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 & ecx & 0x80000000U);
if (hypervisor) {
/* 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)
);
NULSTR_FOREACH_PAIR(j, k, cpuid_vendor_table)
if (streq(sig.text, j)) {
if (id)
*id = k;
return 1;
}
}
for (i = 0; i < ELEMENTSOF(dmi_vendors); i++) {
char *s;
@ -3772,60 +3823,14 @@ int detect_vm(const char **id) {
}
}
/* http://lwn.net/Articles/301888/ */
zero(sig);
#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)
);
if (ecx & 0x80000000U) {
/* 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)
);
NULSTR_FOREACH_PAIR(j, k, cpuid_vendor_table)
if (streq(sig.text, j)) {
if (id)
*id = k;
return 1;
}
if (hypervisor) {
if (id)
*id = "other";
return 1;
}
#endif
#endif
return 0;
}