Autoconfify, add CPUID helper program to detect HVM domains (Paolo Bonzini).

[virt-what.git] / virt-what-cpuid-helper.c

diff --git a/virt-what-cpuid-helper.c b/virt-what-cpuid-helper.c
new file mode 100644 (file)
index 0000000..76ce6a2
--- /dev/null
+++ b/virt-what-cpuid-helper.c
@@ -0,0 +1,62 @@
+/* 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__)
+void
+cpu_sig (char *sig)
+{
+  unsigned int eax = 0x40000000;
+  unsigned int *sig32 = (unsigned int *)sig;
+  asm volatile (
+        "xor %%ebx, %%ebx; cpuid"
+        : "=a" (eax), "=b" (sig32[0]), "=c" (sig32[1]), "=d" (sig32[2])
+        : "0" (eax));
+  sig[12] = 0;
+}
+#else
+void
+cpu_sig (char *sig)
+{
+  /* nothing for other architectures */
+}
+#endif
+
+int
+main()
+{
+  char sig[13];
+
+  memset (sig, 0, sizeof sig);
+
+  cpu_sig (sig);
+
+  puts (sig);
+  /* Possible values:
+   * KVMKVMKVM     KVM guest
+   * XenVMMXenVMM  Xen HVM guest
+   */
+
+  return 0;
+}