freebsd-src/stand/libsa/x86/hypervisor.c
Warner Losh 3e15b01d69 libsa: Remove redundant sys/cdefs.h
Sponsored by:		Netflix
2024-02-22 09:31:57 -07:00

50 lines
1.8 KiB
C

/*-
* Copyright (c) 2013-2019 Juniper Networks, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <stand.h>
#include <machine/cpufunc.h>
#include <machine/specialreg.h>
const char *
x86_hypervisor(void)
{
static union {
struct {
u_int high;
char name[13];
} hv;
u_int regs[4];
} u;
/* Return NULL when no hypervisor is present. */
do_cpuid(1, u.regs);
if ((u.regs[2] & CPUID2_HV) == 0)
return (NULL);
/* Return the hypervisor's identification. */
do_cpuid(0x40000000, u.regs);
return (u.hv.name);
}