#!/bin/sh
#
# kvm-ok - check whether the CPU we're running on supports KVM acceleration
# Copyright (C) 2008-2010 Canonical Ltd.
#
# Authors: Dustin Kirkland <kirkland@canonical.com>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 3,
# as published by the Free Software Foundation.
#
# 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, see <http://www.gnu.org/licenses/>.
set -e

verdict() {
	# Print verdict
	if [ "$1" = "0" ]; then
		echo "KVM acceleration can be used"
		exit 0
	else
		echo "KVM acceleration can NOT be used"
		exit 1
	fi
}

# First, check cpu flags
if egrep "^flags.*:.*(svm|vmx)" /proc/cpuinfo > /dev/null; then
	echo "INFO: Your CPU supports KVM extensions"
else
	echo "INFO: Your CPU does not support KVM extensions"
	verdict 1
fi

# Check for bios messages in dmesg
# BUG: Checking dmesg is the best we can do in userspace at this time.
#      Ideally, the kernel would improve it's reporting by setting a
#      flag such as svm_disabled|vmx_disabled in /proc/cpuinfo's flags.
if dmesg | grep -qs "kvm: disabled by bios"; then
	echo "INFO: KVM is disabled by your BIOS"
	echo "HINT: Enter your BIOS setup and enable Virtualization Technology (VT),"
	echo "      and then hard poweroff/poweron your system"
	verdict 1
fi

# Now, check that the device exists
if [ -e /dev/kvm ]; then
	echo "INFO: /dev/kvm exists"
else
	echo "INFO: /dev/kvm does not exist"
	grep -qs "^flags.*:.*vmx" /proc/cpuinfo && brand="intel" || brand="amd"
	echo "HINT: sudo modprobe kvm_$brand"
	verdict 1
fi

verdict 0