104 lines
3.0 KiB
C
104 lines
3.0 KiB
C
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/*
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* This program is derived from systemd.
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*
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* Copyright 2011 Lennart Poettering
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2.1 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdbool.h>
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#include <stdint.h>
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#include <string.h>
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#define streq(a, b) (!strcmp(a, b))
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#define ELEMENTSOF(a) (sizeof(a) / sizeof((a)[0]))
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enum {
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VIRTUALIZATION_NONE,
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VIRTUALIZATION_VM_OTHER,
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VIRTUALIZATION_MICROSOFT,
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};
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static int detect_vm_cpuid(void) {
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static const struct {
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const char *cpuid;
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int id;
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} cpuid_vendor_table[] = {
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/* http://msdn.microsoft.com/en-us/library/ff542428.aspx */
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{ "Microsoft Hv", VIRTUALIZATION_MICROSOFT },
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};
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uint32_t eax, ecx;
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bool hypervisor;
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/* http://lwn.net/Articles/301888/ */
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#if defined (__i386__)
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#define REG_a "eax"
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#define REG_b "ebx"
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#elif defined (__amd64__)
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#define REG_a "rax"
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#define REG_b "rbx"
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#endif
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/* First detect whether there is a hypervisor */
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eax = 1;
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__asm__ __volatile__ (
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/* ebx/rbx is being used for PIC! */
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" push %%"REG_b" \n\t"
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" cpuid \n\t"
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" pop %%"REG_b" \n\t"
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: "=a" (eax), "=c" (ecx)
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: "0" (eax)
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);
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hypervisor = !!(ecx & 0x80000000U);
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if (hypervisor) {
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union {
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uint32_t sig32[3];
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char text[13];
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} sig = {};
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unsigned j;
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/* There is a hypervisor, see what it is */
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eax = 0x40000000U;
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__asm__ __volatile__ (
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/* ebx/rbx is being used for PIC! */
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" push %%"REG_b" \n\t"
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" cpuid \n\t"
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" mov %%ebx, %1 \n\t"
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" pop %%"REG_b" \n\t"
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: "=a" (eax), "=r" (sig.sig32[0]), "=c" (sig.sig32[1]), "=d" (sig.sig32[2])
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: "0" (eax)
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);
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for (j = 0; j < ELEMENTSOF(cpuid_vendor_table); j ++)
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if (streq(sig.text, cpuid_vendor_table[j].cpuid))
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return cpuid_vendor_table[j].id;
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return VIRTUALIZATION_VM_OTHER;
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}
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return VIRTUALIZATION_NONE;
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}
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int main(void)
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{
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return detect_vm_cpuid() != VIRTUALIZATION_MICROSOFT;
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}
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