How to enable KVM for Poky qemu - Revision history

Khem: /* Change the kvm dev ownership for non-root user */

2017-06-08T18:20:38Z

Change the kvm dev ownership for non-root user

← Older revision		Revision as of 18:20, 8 June 2017
Line 41:		Line 41:
	qemu is started as non-root user in poky, but ''/dev/kvm'' from some distribution remains root:root that only allow root to use KVM. To work around this, we need create a new group named '''kvm''', and make both ''/dev/kvm'' and the non-root user belongs to it.		qemu is started as non-root user in poky, but ''/dev/kvm'' from some distribution remains root:root that only allow root to use KVM. To work around this, we need create a new group named '''kvm''', and make both ''/dev/kvm'' and the non-root user belongs to it.

	sudo ~~addgroup~~ --system kvm		sudo groupadd --system kvm
	sudo ~~adduser~~ $USER kvm		sudo gpasswd -a $USER kvm
	sudo chown root:kvm /dev/kvm		sudo chown root:kvm /dev/kvm
	sudo chmod 0660 /dev/kvm		sudo chmod 0660 /dev/kvm

Bill Randle: /* Change the kvm dev ownership for non-root user */

2016-08-19T19:24:13Z

Change the kvm dev ownership for non-root user

← Older revision		Revision as of 19:24, 19 August 2016
Line 51:		Line 51:
	On a system that runs udev, you will probably need to add the following line somewhere in your udev configuration so it will automatically give the right group to the newly created device (i-e for ubuntu add a line to /etc/udev/rules.d/40-permissions.rules).		On a system that runs udev, you will probably need to add the following line somewhere in your udev configuration so it will automatically give the right group to the newly created device (i-e for ubuntu add a line to /etc/udev/rules.d/40-permissions.rules).

	KERNEL=="kvm", GROUP="kvm"		KERNEL=="kvm", GROUP="kvm", MODE="0660"

SaulWold: /* running qemu with KVM enabled */

2015-11-23T22:24:11Z

running qemu with KVM enabled

← Older revision		Revision as of 22:24, 23 November 2015
Line 59:		Line 59:

	== running qemu with KVM enabled ==		== running qemu with KVM enabled ==
	just append "kvm" parameter to the ''~~poky-qemu~~'' like this		just append "kvm" parameter to the ''runqemu'' like this

	$ ~~poky-qemu~~ qemux86 kvm		$ runqemu qemux86 kvm

Khem: /* Change the kvm dev ownership for non-root user */

2013-03-29T08:13:04Z

Change the kvm dev ownership for non-root user

← Older revision		Revision as of 08:13, 29 March 2013
Line 41:		Line 41:
	qemu is started as non-root user in poky, but ''/dev/kvm'' from some distribution remains root:root that only allow root to use KVM. To work around this, we need create a new group named '''kvm''', and make both ''/dev/kvm'' and the non-root user belongs to it.		qemu is started as non-root user in poky, but ''/dev/kvm'' from some distribution remains root:root that only allow root to use KVM. To work around this, we need create a new group named '''kvm''', and make both ''/dev/kvm'' and the non-root user belongs to it.

	$ sudo addgroup --system kvm		sudo addgroup --system kvm
	$ sudo adduser $USER kvm		sudo adduser $USER kvm
	$ sudo chown root:kvm /dev/kvm		sudo chown root:kvm /dev/kvm
	$ sudo chmod 0660 /dev/kvm		sudo chmod 0660 /dev/kvm

	The output of "ls -l /dev/kvm" should be like this:		The output of "ls -l /dev/kvm" should be like this:

Gzhai: /* Change the kvm dev ownership for non-root user */

2010-12-22T06:04:01Z

Change the kvm dev ownership for non-root user

← Older revision		Revision as of 06:04, 22 December 2010
Line 48:		Line 48:
	The output of "ls -l /dev/kvm" should be like this:		The output of "ls -l /dev/kvm" should be like this:
	crw-rw----+ 1 root kvm 10, 232 2010-07-02 09:27 /dev/kvm		crw-rw----+ 1 root kvm 10, 232 2010-07-02 09:27 /dev/kvm

			On a system that runs udev, you will probably need to add the following line somewhere in your udev configuration so it will automatically give the right group to the newly created device (i-e for ubuntu add a line to /etc/udev/rules.d/40-permissions.rules).

			KERNEL=="kvm", GROUP="kvm"


	Note		Note

Gzhai: Created page with '= enable KVM for poky qemu = == KVM introduction == ''KVM'' (for Kernel-based Virtual Machine) is a full virtualization solution for Linux on x86 hardware containing virtualizat…'

2010-12-22T01:20:56Z

Created page with '= enable KVM for poky qemu = == KVM introduction == ''KVM'' (for Kernel-based Virtual Machine) is a full virtualization solution for Linux on x86 hardware containing virtualizat…'

New page

= enable KVM for poky qemu =
== KVM introduction ==

''KVM'' (for Kernel-based Virtual Machine) is a full virtualization solution for Linux on x86 hardware containing virtualization extensions (Intel VT or AMD-V). It consists of a loadable kernel module, '''kvm.ko''', that provides the core virtualization infrastructure and a processor specific module, '''kvm-intel.ko''' or kvm-amd.ko. KVM also requires a modified QEMU although work is underway to get the required changes upstream.

Compared with native qemu, a pure emulator, KVM has better performance based on virtualization as most of guest instruction can be executed directly on the host processor.

== detect VT support ==
You need make sure your x86 processor support VT before using KVM.

With a recent enough Linux kernel, run the command:

$ egrep '^flags.*(vmx|svm)' /proc/cpuinfo

If something shows up, you have VT. You can also check the processor model name (in `/proc/cpuinfo`) in the vendor's web site.

Note:

* You'll never see (vmx|svm) in /proc/cpuinfo if you're currently running in in a dom0 or domU. The Xen hypervisor suppresses these flags in order to prevent hijacking.

* Some manufacturers disable VT in the machine's BIOS, in such a way that it cannot be re-enabled.

* `/proc/cpuinfo` only shows virtualization capabilities starting with Linux 2.6.15 (Intel) and Linux 2.6.16 (AMD). Use the `uname -r` command to query your kernel version.

In case of doubt, contact your hardware vendor.

== get the KVM module ==

The quick & easy way for this is just using it from your distribution. As of now, all major community and enterprise distributions contain kvm kernel modules; these are either installed by default or require installing a kvm package. For someone looking for stability, these are the best choice. No effort is needed to build or install the modules, support is provided by the distribution, and the distribution/module combination is well tested.

In other cases, you need refer [http://www.linux-kvm.org/page/Getting_the_kvm_kernel_modules getting kvm modules].

After getting the modules, you can install them into kernel by

$ sudo modprobe kvm-intel

== make KVM aware QEMU ==
Upstream QEMU has already supported KVM, and I have already checked in one patch to enable it. So you get a KVM capable qemu after poky build.

== Change the kvm dev ownership for non-root user ==
qemu is started as non-root user in poky, but ''/dev/kvm'' from some distribution remains root:root that only allow root to use KVM. To work around this, we need create a new group named '''kvm''', and make both ''/dev/kvm'' and the non-root user belongs to it.

$ sudo addgroup --system kvm
$ sudo adduser $USER kvm
$ sudo chown root:kvm /dev/kvm
$ sudo chmod 0660 /dev/kvm

The output of "ls -l /dev/kvm" should be like this:
crw-rw----+ 1 root kvm 10, 232 2010-07-02 09:27 /dev/kvm

Note
* You need log out then log in the non-root user to take the effect
* Some distributions have already made this, so that we can skip this step

== running qemu with KVM enabled ==
just append "kvm" parameter to the ''poky-qemu'' like this

$ poky-qemu qemux86 kvm