linux_kernel/arch/x86/kernel/cpu/hypervisor.c

/*
 * Common hypervisor code
 *
 * Copyright (C) 2008, VMware, Inc.
 * Author : Alok N Kataria <akataria@vmware.com>
 *
 * 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, GOOD TITLE or
 * NON INFRINGEMENT.  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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */

#include <linux/init.h>
#include <linux/export.h>
#include <asm/processor.h>
#include <asm/hypervisor.h>

static const __initconst struct hypervisor_x86 * const hypervisors[] =
{
#ifdef CONFIG_XEN_PV
	&x86_hyper_xen_pv,
#endif
#ifdef CONFIG_XEN_PVHVM
	&x86_hyper_xen_hvm,
#endif
	&x86_hyper_vmware,
	&x86_hyper_ms_hyperv,
#ifdef CONFIG_KVM_GUEST
	&x86_hyper_kvm,
#endif
};

const struct hypervisor_x86 *x86_hyper;
EXPORT_SYMBOL(x86_hyper);

static inline void __init
detect_hypervisor_vendor(void)
{
	const struct hypervisor_x86 *h, * const *p;
	uint32_t pri, max_pri = 0;

	for (p = hypervisors; p < hypervisors + ARRAY_SIZE(hypervisors); p++) {
		h = *p;
		pri = h->detect();
		if (pri != 0 && pri > max_pri) {
			max_pri = pri;
			x86_hyper = h;
		}
	}

	if (max_pri)
		pr_info("Hypervisor detected: %s\n", x86_hyper->name);
}

void __init init_hypervisor_platform(void)
{

	detect_hypervisor_vendor();

	if (!x86_hyper)
		return;

	if (x86_hyper->init_platform)
		x86_hyper->init_platform();
}

bool __init hypervisor_x2apic_available(void)
{
	return x86_hyper                   &&
	       x86_hyper->x2apic_available &&
	       x86_hyper->x2apic_available();
}

void hypervisor_pin_vcpu(int cpu)
{
	if (!x86_hyper)
		return;

	if (x86_hyper->pin_vcpu)
		x86_hyper->pin_vcpu(cpu);
	else
		WARN_ONCE(1, "vcpu pinning requested but not supported!\n");
}