text: /*
   * This file is part of the coreboot project.
   *
   * Copyright (C) 2007-2009 coresystems GmbH
   * Copyright (C) 2011 The ChromiumOS Authors.  All rights reserved.
   *
   * 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; version 2 of
   * the License.
   *
   * 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.
   */
  
  #include <console/console.h>
  #include <cpu/x86/msr.h>
  #include "common.h"
  
  #define IA32_FEATURE_CONTROL	0x3a
  #define CPUID_VMX		(1 << 5)
  #define CPUID_SMX		(1 << 6)
  
  void set_vmx(void)
  {
  	struct cpuid_result regs;
  	msr_t msr;
  	int enable = IS_ENABLED(CONFIG_ENABLE_VMX);
  	int lock = IS_ENABLED(CONFIG_SET_VMX_LOCK_BIT);
  
  	regs = cpuid(1);
  	/* Check that the VMX is supported before reading or writing the MSR. */
  	if (!((regs.ecx & CPUID_VMX) || (regs.ecx & CPUID_SMX))) {
  		printk(BIOS_DEBUG, "CPU doesn't support VMX; exiting\n");
  		return;
  	}
  
  	msr = rdmsr(IA32_FEATURE_CONTROL);
  
  	if (msr.lo & (1 << 0)) {
  		printk(BIOS_ERR, "VMX is locked, so %s will do nothing\n",
  			__func__);
  		/* VMX locked. If we set it again we get an illegal
  		 * instruction
  		 */
  		return;
  	}
  
  	/* The IA32_FEATURE_CONTROL MSR may initialize with random values.
  	 * It must be cleared regardless of VMX config setting.
  	 */
  	msr.hi = msr.lo = 0;
  
  	if (enable) {
  		msr.lo |= (1 << 2);
  		if (regs.ecx & CPUID_SMX)
  			msr.lo |= (1 << 1);
  	}
  
  	wrmsr(IA32_FEATURE_CONTROL, msr);
  
  	if (lock) {
  		/* Set lock bit */
  		msr.lo |= (1 << 0);
  		wrmsr(IA32_FEATURE_CONTROL, msr);
  	}
  
  	printk(BIOS_DEBUG, "VMX status: %s, %s\n",
  		enable ? "enabled" : "disabled",
  		lock ? "locked" : "unlocked");
  }
  