View source for Running an x86 Yocto Linux image under QEMU KVM

!!!!Page under re-construction!!!

== Host OS preparation (VM manager host OS) ==

Steps:
 
1.[https://wiki.yoctoproject.org/wiki/How_to_enable_KVM_for_Poky_qemu Enable KVM] on the host machine
 
2. Enable on host OS vhost-net virtio networking accelerator to mitigate overhead on QEMU virtualization environment.
<br/>Load vhost-net module on KVM Host.
 [root@dlp ~]#modprobe vhost_net
 [root@dlp ~]#lsmod | grep vhost
The result of running the commands should be similar to the following:
 vhost_net 24241 0
 macvtap 7867 1 vhost_net
 tun16825 3 vhost_net

Note
* You need log out then log in the non-root user to take the effect
 
3. Start the VM using the line below:
 
 ubik@sentry:~/yoctoproject/build$ sudo kvm -kernel /home/ubik/yoctoproject/build/tmp/deploy/images/bzImage-qemux86.bin -net nic,model=virtio -net \
     tap,vlan=0,ifname=tap0,script=no,downscript=no,vhost=on -drive file=/home/ubik/yoctoproject/build/tmp/deploy/images/core-image-core-qemux86.ext3,if=virtio \
    -show-cursor -usb - usbdevice wacom-tablet -vga vmware -no-reboot -enable-kvm -cpu host -m 128 --append "vga=0 root=/dev/vda rw mem=128M \
    ip=192.168.7.2::192.168.7.1:255.255.255.0 oprofile.timer=1 " 
 
This is an example of running a virtualized Yocto image, with KVM active, cpu host features exported in the Yocto VM, paravirtualization enabled, and using virtio interfaces for disk access and networking.
On a machine equipped with a Core i7 2600 (3.4GHz, 4 cores, 8 threads)/8 GB RAM/Intel SSD G3 120GB qemux86 Yocto Linux boots in around 7 seconds for a core-image-x11. The same image boots in 20 seconds without virtualization optimizations and feels slower in usage.

== Guest OS preparation ==
 
The following kernel configs needs to be enabled for Yocto Linux guest OS:

 [...]
 CONFIG_PARAVIRT_GUEST=y
 CONFIG_KVM_CLOCK=y
 CONFIG_KVM_GUEST=y
 CONFIG_PARAVIRT=y
 CONFIG_PARAVIRT_CLOCK=y
 CONFIG_VIRTIO_MMIO=y
 [..]

Screenshots example:
[[File:Core-image-x11.png|thumb|upright=2|left|Yocto Linux guest running under QEMU KVM with paravirtualization and virtio tech.]]
[[File:YL-guest-QEMU-cpu-host.png|thumb|left|upright=2|CPU host features exported to Yocto Linux guest.]]