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/* virt-what-cpuid-helper: Are we running inside KVM or Xen HVM?
* Copyright (C) 2008 Red Hat Inc.
*
* 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
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/* This program was suggested by Gleb Natapov and written by Paolo
* Bonzini, with a few modifications by Richard W.M. Jones.
*/
#include <stdio.h>
#include <string.h>
#if defined(__i386__) || defined(__x86_64__)
static unsigned int
cpuid (unsigned int eax, char *sig)
{
unsigned int *sig32 = (unsigned int *) sig;
asm volatile (
"xchgl %%ebx,%1; xor %%ebx,%%ebx; cpuid; xchgl %%ebx,%1"
: "=a" (eax), "+r" (sig32[0]), "=c" (sig32[1]), "=d" (sig32[2])
: "0" (eax));
sig[12] = 0;
return eax;
}
static void
cpu_sig (void)
{
char sig[13];
unsigned int base = 0x40000000, leaf = base;
unsigned int max_entries;
memset (sig, 0, sizeof sig);
max_entries = cpuid (leaf, sig);
puts (sig);
/* Most hypervisors only have information in leaf 0x40000000, but
* upstream Xen contains further leaf entries (in particular when
* used with Viridian [HyperV] extensions). CPUID is supposed to
* return the maximum leaf offset in %eax, so that's what we use,
* but only if it looks sensible.
*/
if (max_entries > 3 && max_entries < 0x10000) {
for (leaf = base + 0x100; leaf <= base + max_entries; leaf += 0x100) {
memset (sig, 0, sizeof sig);
cpuid (leaf, sig);
puts (sig);
}
}
}
#else /* !i386, !x86_64 */
static void
cpu_sig (void)
{
/* nothing for other architectures */
}
#endif
int
main()
{
cpu_sig ();
return 0;
}
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